Cli
Fourth Edition
mica
Surgery; in
Genera '
Edited by
R.M. Kirk
WJ. Ribbans
Clinical
Surgery in
General
RCS Course Manua
Commissioning Editor: Laurence Hunter
Project Development Manager: Janice Urquhart
Project Manager: Frances Affleck
Designer: Erik Bigland
Illustration Manager: Bruce Hogarth
Illustrator: Ethan Danielson
Clinical
Surgery in
General
RCS Course Manua
Edited by
R. M. KirkMSFRcs
Honorary Consultant Surgeon, The Royal Free Hospital, London, UK
W. J. Ribbans frcs frcs Ed onh
Consultant Orthopaedic Surgeon, Northampton General Hospital,
Northampton, UK
FOURTH EDITION
s»
CHURCHILL
LIVINGSTONE
EDINBURGH LONDON NEW YORK OXFORD PHILADELPHIA ST LOUIS SYDNEY TORONTO
2004
CHURCHILL LIVINGSTONE
An imprint of Elsevier Science Limited
© Royal College of Surgeons 1993
© Royal College of Surgeons 1996
© Royal College of Surgeons 1999
© R. M. Kirk, W. J. Ribbans 2004 All rights reserved.
The right of R. M. Kirk and W. J. Ribbans to be identified as
authors of this work has been asserted by them in
accordance with the Copyright, Designs and Patents Act
1988
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contraindications. It is the responsibility of the practitioner,
relying on experience and knowledge of the patient, to
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ELSEVIER
SCIENCE
First edition 1993
Second edition 1996
Third edition 1999
Fourth edition 2004
ISBN 443 07262
British Library Cataloguing in Publication Data
A catalogue record for this book is available from the
British Library
Library of Congress Cataloging in Publication Data
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of Congress
Printed in China
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policy is to use
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from sustainable forests
Preface
What is the book about? Basic science texts deal with
anatomy, physiology and pathology. Clinical textbooks
deal in a systematic manner with guidance on managing
individual patients. We have attempted to create a bridge
between the basic sciences and their incorporation into
clinical practice. In the past general surgery dominated
teaching and postgraduate surgical examinations, but
many of the included subjects have successively been
separated into specialities. In order to offer the best
management to our patients, we may need to know about
specialities outside of surgery, such as imaging tech-
niques, radiotherapy, cancer chemotherapy, and terminal
care. We have tried to identify and demonstrate some of
those subjects.
The chapters fall into three types. Some are intended to
be revelatory; not intended to cover the subject in detail
but offering a simply presented, comprehensible account,
which can be expanded by further reading, for example,
Pathogenesis of cancer. Some are for reference, because
apart from the principles, the specific details cannot be
retained in full and need to be looked up, for example
Fluid, electrolyte and acid/base balance. The third type are
intended to emphasize that becoming a surgeon is
more than acquiring facts; even more important is the
acquisition of professional attitudes of common sense,
competence, commitment, and compassion. Books cannot
transmit attitude, they can merely set out for young
surgeons the high personal and professional standards
that are crucial, for example in Good surgical practice.
Experts often find it difficult to write 'down' for
trainees, and especially for those whose first language is
not English and those taught medicine in languages other
than English. Teachers often feel, quite reasonably, that
aspiring experts should learn the basic specialist terms,
but too often the trainees learn the words without fully
understanding their clear meaning. Consequently, the
contributors have been exhorted to use simple, direct
language, define complex terms and acronyms, and,
when in doubt, to prefer comprehensibility over compre-
hensiveness. Most have been very tolerant.
A minority of readers studied Latin or Greek at school
and even those who have done so, do not always recognize
the words when they encounter them in medical texts. One
of us, deprived of such an education, vividly remembers
encountering the word 'parotid' in a dictionary; it was a
revelation to discover that the parotid gland is simply the
'beside the ear gland' (G para = beside + otis = ear). In con-
sequence of this the contributors have been encouraged to
define interesting or difficult terms. Although it is often
frowned upon, the eponymous (G epi = upon + onyma = a
name; a distinguishing name) titles of diseases, instru-
ments, clinical features, incisions and manoeuvres honour
those who described or recognized them. They could be
inserted as footnotes, or in a glossary at the end of the
book. They do not get overlooked within the text and they
offer struggling readers moments of relaxation.
Surgery was traditionally taught within the master/
apprentice relationship. The master is often not con-
sciously aware of the tacit skills he or she has acquired and
passes on to the apprentice by example, rather than by
explicit teaching. The trainee is similarly unaware of assim-
ilating it. The transfer of this unrecognized wisdom is often
disparaged as mere skill but is described and extolled by
Michael Polanyi in his book Personal knowledge? Words
alone and this book alone, cannot contain the whole of
knowledge. In the present day obsession with objectivity,
information that defies statistical analysis is often ignored,
when in reality it is only our ignorance of it that prevents
us from utilizing it. The really important truths defy objec-
tive description. Bernard Levin 2 stated, 'Most things that
are fundamentally important are not susceptible to logical
analysis. I would go so far as to state that that is how we
know they are fundamentally important.' Because of the
need for trainees to rotate through the sub-specialities,
long-term master/ apprentice relationships are truncated.
As a trainee, assimilate as much as possible by reading but
Michael Polanyi. Personal knowledge, Routledge & Keegan
Paul, London, 1958
2 Times, London, 13 th February 1989
V
I
PREFACE
be receptive to the lessons you can acquire through your
contact with experienced senior colleagues. In the longer
term, when you become a senior/ be receptive to the fresh
lessons to be learned from your juniors.
Apology
There is no epicene (G epi - upon + koinos - common;
common to both genders) word for he and she/ him and
her, his and hers. Most of the older textbooks recognized
only male surgeons but this must no longer be so.
However/ there are times when specifying both sexes
several times in a sentence becomes tedious; repeated
cutting from singular to plural is clumsy. Some sexually
attributable words have acquired special meanings, such
as Master with the connotation of teacher or leader;
Mistress has a quite different connotation!
2003
R. M. K.
W.J.R
Acknowledgements
We are grateful for the expert and experienced advice of
Laurence Hunter r the pleasure of working once again
with Janice Urquhart and with a newly encountered and
expert copy editor, Rosaline Crum. The contributors have
generously agreed to forego any payment in order that
the royalties can be donated to the Royal College of
Surgeons of England towards funding the very successful
Research Fellowships.
Professor Marc Winslet, Head of the Academic De-
partment of Surgery at the Royal Free Hospital/ has not
only contributed to the book, but he has also generously
allowed the organization and editing of the book to be
centred within the Department.
VI
Contributors
Tushar Agarwal MB BS MRCS(Ed)
Specialist Registrar Academic Surgical Unit, St Mary's
Hospital, London, UK
Peter L. Amlot MB BS FRCP
Senior Lecturer, Department of Immunology, Royal Free
and University College Medical School, London, UK
J. L. Atkins MSc FRCS
Registrar in Plastic Surgery, Royal Free Hospital,
London, UK
Wynne Aveling MA MB BChir FRCA
Consultant Anaesthetist, University College London
Hospitals, London, UK
Daryll M. Baker PhD FRCS(Gen)
Consultant Vascular Surgeon, Royal Free Hospital,
London, UK
Tom Bates MB BS MRCS LRCP FRCS
Consultant Surgeon in General Surgery, The William
Harvey Hospital, Ashford, Kent, UK
T. J. Beale FRCS(Eng) FRCR
Consultant Radiologist, Central Middlesex Hospital,
London, UK
Satyajit Bhattacharya MS MPhil FRCS
Consultant Surgeon, Hepatic and Pancreatic Surgery
Unit, The Royal London Hospital, London, UK
Colin Bicknell BM MRCS
Research Fellow, Regional Vascular Unit, St Mary's
Hospital, London, UK
Laura J. Buist MD FRCS
Consultant Transplant Surgeon, Queen Elizabeth
Hospital, Birmingham, UK
Peter E. M. Butler FRCSI FRCS FRCS(Plast)
Consultant Plastic Surgeon, Royal Free Hospital,
London, UK
N. J. W. Cheshire MD FRCS FRCS(gen)
Consultant Vascular Surgeon, Regional Vascular Unit,
St Mary's Hospital, London, UK
John P. S. Cochrane MS FRCS
Consultant Surgeon, Whittington Hospital, London, UK
Richard E. C. Collins FRCS(Eng) FRCS(Ed)
Chairman Intercollegiate Board in General Surgery
1998-2001; Consultant General and Endocrine Surgeon,
Kent and Canterbury Hospital, Canterbury, UK
Carmel Coulter FRCR FRCP
Consultant Clinical Oncologist, St Mary's Hospital,
London, UK
K. Cox MB MS MA FRCS FRACS FACS
Emeritus Professor of Surgery, University of New South
Wales, New South Wales, Australia; Formerly Director
of the World Health Organization Regional Training
Centre for Health Development
M. K. H. Crumplin MB FRCS
Honorary Consultant Surgeon, Maelor Hospital, North
East Wales Trust, UK
Professor Sir Ara Darzi KBE
Professor of Surgery and Head of Department of
Surgical Oncology and Technology, Imperial College of
Science, Technology and Medicine, St Mary's Hospital,
London, UK
Andrew Davenport MA MD FRCP
Director, International Society of Hemodialysis;
Consultant Renal Physician and Honorary Senior
Lecturer, Royal Free Hospital, London, UK
VII
1
CONTRIBUTORS
Brian Davidson MB ChB MD FRCS
Professor of Surgery, Royal Free and University College
School of Medicine, London, UK
J. L> Dawson (deceased)
Ahmet Dogan MD PhD MRCPath
Senior Lecturer and Consultant, Department of
Histopathology, Royal Free and University College
Medical School, UCL Hospitals, London, UK
Glenn Douglas BA(Hons) IPFA MIHSM
Chief Executive, Ashford and St Peter's Hospitals NHS
Trust, Eastbourne, UK
Len Doyal BA MSc
Professor of Medical Ethics, Barts and the London
School of Medicine, Queen Mary, University of London,
London, UK
Peter A. Driscoll BSc MD FRCS FFAEM
Consultant in Emergency Medicine, Hope Hospital,
Salford, UK
Roshan Fernando MB ChB FRCA
Consultant Anaesthetist and Honorary Senior Lecturer,
Department of Anaesthesia, Royal Free Hospital,
London, UK
F. Kate Gould MB BS FRCPath
Consultant Microbiologist, Freeman Hospital,
Newcastle upon Tyne, UK
Stuart W. T. Gould FRCS
Senior Lecturer in Surgery, Imperial College of Science,
Technology and Medicine, London, UK
Clair S. Gricks BSc PhD
Post Doctoral Research Fellow, Dana Farber Cancer
Institute, Harvard Medical School, Boston, USA
Pierre J. Guillou BSc MD FRCS FRCPS(Glas) FMedSci
Professor of Surgery, St James's University Hospital,
School of Medicine, Leeds, UK
Amy Guppy MRCP BSc
Specialist Registrar, Mount Vernon Cancer Centre,
Northwood, Middlesex, UK
Chris G. Hargreaves BSc MRCP FRCA
Consultant in Intensive Care Medicine and Anaesthesia,
Whittington Hospital, London, UK
John A. Henry FRCP FFAEM
Honorary Consultant, Head of Academic Department of
Accident and Emergency Medicine, Imperial College
Faculty of Medicine, St Mary's Hospital, London, UK
Barrie HiggS MB BS MSc FRCA
Consultant and Honorary Senior Lecturer, Departments
of Anaesthesia and Physiology, Royal Free Hospital and
Royal Free and University College School of Medicine,
London, UK
Daniel Hochhauser MRCP DPhil
Kathleen Ferrier Reader in Medical Oncology, Royal
Free and University College Medical School, London,
UK
R. W. Hoile MS FRCS(Eng)
Consultant General Surgeon, Medway Maritime
Hospital, Gillingham, Kent, UK; Principal Surgical
Coordinator of National Confidential Enquiry into
Perioperative Deaths (NCEPOD)
Robert A. Huddart MA MB BS MRCP FRCR PhD
Senior Lecturer and Honorary Consultant, Institute of
Cancer Research and Royal Marsden Hospital, Surrey,
UK
Iain A. Hunter BMedSci BM BS FRCS(Eng)
Clinical Research Fellow, St James's University Hospital,
School of Medicine, Leeds, UK
Donald J. Jeffries BSc MB BS FRCP FRCPath
Professor of Virology and Head of Department of
Medical Microbiology, St Bartholomew's and the Royal
London School of Medicine and Dentistry, London, UK
Jennifer Jones BSc MB BS FRCP FRCA
Consultant Anaesthetist, St Mary's Hospital, London,
UK
R. M. Jones MD FRCA
Professor of Anaesthetics, St Mary's Hospital, London,
UK
Mark A. Hamilton BSc MB BS MRCP
Research Fellow, Centre for Anaesthesia, Middlesex
Hospital, London, UK
R. M. Kirk MS FRCS
Honorary Consultant Surgeon, The Royal Free Hospital,
London, UK
VIII
CONTRIBUTORS
Anna C. Kurowska BSc BA FRCP
Consultant in Palliative Medicine, Whittington Hospital
and Edenhall Marie Curie Centre, London, UK
Sunil R. Lakhani BSc MB BS MD FRCPath
Professor of Breast Cancer Pathology, The Breakthrough
Toby Robins Breast Cancer Research Centre, Institute of
Cancer Research and The Royal Marsden Hospital,
London, UK
David Leaper MD ChM FRCS FRCSEd FRCSGlas FACS
Professor of Surgery, University Hospital of North Tees,
Stockton-on-Tees, UK
Richard C. Leonard BA MRCP FRCA FANZCA FFICANZCA
Consultant Intensivist, St Mary's Hospital, London, UK
Liang Low FRCSI
Specialist Registrar in Surgery, University Hospital of
North Tees, Stockton-on-Tees, UK
Valentine M. Macaulay MD PhD MRCP
Cancer Research UK Senior Clinical Research Fellow and
Honorary Consultant in Medical Oncology, Molecular
Oncology Laboratories, Weatherall Institute of Molecular
Medicine and Oxford Radcliff Trust, Oxford, UK
John W. McClenahan MA MS DiplIndMgt PhD FOR
Fellow in Leadership Development, King's Fund,
London, UK
Paul McMaster MA MB ChM FRCS
Professor of Hepatobiliary Surgery and Transplantation,
Queen Elizabeth Hospital, University of Birmingham,
Birmingham, UK
Caroline A. Marshall MB BS MRCP FRCA
Consultant Anaesthetist, Southampton University
Hospitals Trust, Southampton, UK
Atul B. Mehta MA MB BChir MD FRCP FRCPath
Consultant Haematologist, Royal Free Hospital,
London, UK
Katherine E. Orr MB ChB FRCPath
Consultant Microbiologist and Honorary Senior
Lecturer, Freeman Hospital, Newcastle upon Tyne, UK
Jason Payne-James LLM FRCS (Ed & Eng) DFM
Honorary Senior Research Fellow, Central Middlesex
Hospital, London; Director, Forensic Healthcare
Services, London
Anthony L. G. Peel MA MChir FRCS
Consultant Surgeon, North Tees Hospital, Stockton-on-
Tees, UK
Michael W. Piatt MB BS FRCA
Consultant and Honorary Senior Lecturer in
Anaesthetics and Pain Management, St Mary's Hospital
NHS Trust, London, UK
William J. Ribbans FRCS FRCSEdOrth
Consultant Surgeon, Northampton General Hospital,
Northampton, UK
Jonathan Robin MRCP
Lecturer in Clinical Pharmacology and Intensive Care
Medicine, University College London, London, UK
Gordon J. S. Rustin MD MSc FRCP
Director of Medical Oncology, Mount Vernon Cancer
Centre, Northwood, Middlesex, UK
Michael Saleh MB ChB MSc Bioeng FRCSEd FRCSEng
Professor of Orthopaedic and Traumatic Surgery,
University of Sheffield; Honorary Consultant, Northern
General Hospital, Sheffield; Honorary Consultant,
Sheffield Children's Hospital, Sheffield, UK
Hank J. Schneider FRCS
Consultant General and Paediatric Surgeon, The James
Paget Hospital, Great Yarmouth, UK
J. A. R. Smith PhD FRCS(Ed) FRCS(Eng)
Consultant Surgeon, Northern General Hospital,
Sheffield, UK
Richard W. Morris BSc MSc PhD
Senior Lecturer in Medical Statistics, Department of
Primary Care and Population Sciences, Royal Free and
University College London, London, UK
Paul D. Nathan PhD MRCP
Specialist Registrar Medical Oncology, Department of
Oncology, Royal Free Hospital, London, UK
Martin Smith MB ChB FRCSEd (A&E) FFAEM
Specialist Registrar in Emergency Medicine, Hope
Hospital, Salford UK
Vinnie Sodhi MB BS BSc FRCA
Portex Research Fellow in Obstetric Anaesthesia,
Department of Anaesthesia, Royal Free Hospital,
London, UK
IX
1
CONTRIBUTORS
Jeremy J. T. Tate MS FRCS
Consultant Surgeon, Royal United Hospital, Bath, UK
Clare P. E Taylor MB BS PhD MRCP MRCPath
Consultant in Haematology and Transfusion Medicine,
Royal Free Hospital and National Blood Service,
London, UK
Adrian Tookman MB BS FRCP
Medical Director, Edenhall Marie Curie Centre, London;
Consultant in Palliative Medicine, Royal Free Hospital,
London, UK
Robin Touquet RD FRCS FFAEM
Consultant in Accident and Emergency Medicine,
St Mary's Hospital, London, UK
Ines Ushiro-Lumb MB BS MSc MRCPath
Consultant Virologist, Department of Virology, Barts
and The London NHS Trust, London, UK
Patricia A. Ward MB BS MRCP FRCSEd(A&E) FFAEM
Director of Resuscitation, Accident and Emergency
Department, St Mary's Hospital, London, UK
Denis Wilkins MB ChB MD FRCS ILT
Consultant General and Vascular Surgeon, Derriford
Hospital, Plymouth; Chairman, Court of Examiners,
Royal College of Surgeons of England; Chairman of the
Specialist Advisory Committee in Training in General
Surgery for Great Britain and Ireland
M. C. Winslet MS FRCS
Professor of Surgery and Head of Department,
University Department of Surgery, Royal Free Hospital,
London, UK
Gillian M. H. Wray MB BS FRCA
Consultant in Anaesthesia and Intensive Care Medicine,
St Bartholomew's Hospital, London, UK
Contents
SECTION 1
EMERGENCY
SECTION 2
PATIENT ASSESSMENT
1. Resuscitation 3
R. Touquet, P. A. Ward, M. W. Piatt J- A Henry
2. Trauma 18
M. Smith, P. A Driscoll
3. Clinical diagnosis 49
R. M. Kirk
4. Investigations 53
N. J. W. Cheshire, C Bicknell
5. Imaging techniques 59
S. W. T. Gould, T. Agarwal, T. J. Beafe
6. Influence of co-existing disease 64
R. M. Jones, C. A. Marshall
7. Immunity in surgery 82
P. L Amlot, C S. G ricks
8. Haematological assessment and blood
component therapy 90
C P. F. Taylor, A. B. Mehta
9. Fluid, electrolyte and acid-base balance 107
W. Ave ling, M. A. Hamilton
10. Nutritional support 125
J. Payne James
11. Clinical pharmacology 131
J. Robin
12. Evidence-based practice 138
J. W. McLenahan
13. Decision making 144
R. M. Kirk, K. Cox
CONTENTS
SECTION 3
PREPARATIONS FOR SURGERY
SECTION 4
OPERATION
14. Consent for surgical treatment 155
L Doyal
15. Preoperative preparation for surgery 165
S. Bhattacharya, G. M. H. Wray
16. Preoperative assessment and anaesthesia 172
M. W. Piatt
17. Operating theatres and special equipment 183
M. K. H. Crump! in
18. Adjuncts to surgery 199
A. L. G. Peel
19. Prevention of infection in surgical practice 206
K. E. Orr, F. K. Gould
20. The risks to surgeons of nosocomial virus
transmission 215
D. J. Jeffries, I. Ushiro-Lumb
21. Good surgical practice 225
R. M. Kirk, J. Dawson
22. Surgical access: incisions, and the management
of wounds 230
D. J. Lea per, L Low
23. Minimal access surgery 237
A. Darzi
24. Principles of skin cover 241
P. E. M. Butler, J. L. Atkins
25. Transplantation 249
P. McMaster, L. J. Buist
SECTION 5
MALIGNANT DISEASE
26. Pathogenesis of cancer 259
P. D. Nathan, D. Hochhauser
27. Principles of surgery for malignant disease 265
P. J. Guiflou, I. A. Hunter
28. Principles of radiotherapy 271
R. A. Huddart
29. Cancer chemotherapy 284
V. M. Macaulay, C Coulter
30. Tumour markers 302
G. J. S. Rust in, A. E. Guppy
XII
CONTENTS
.
SECTION 6
POSTOPERATIVE
SECTION 8
GENERAL CONSIDERATIONS
31. The body's response to surgery 313
J. P. S. Cochrane, C G. Hargreaves
32. Wound healing 322
S. R. La khan i, A. Dogan
33. Responses of connective tissue and bone 331
W. J. Ribbans, M. Safeh
34. Postoperative care 349
J. J, T. Tate
35. Management of postoperative pain 357
V, Sodhi, R. Fernando
SECTION 7
COMPLICATIONS
36. Complications: prevention and management
373
J. A. R. Smith
37. Intensive care 388
J. Jones, R. C Leonard
38. Dialysis 398
A. Davenport
39. Chronic illness, rehabilitation and terminal care
402
A. C Kurowska, A. Tookman
40. Genetic aspects of surgery 417
M. C Winslet
41. Screening for surgical disease 423
T. Bates
42. Audit 428
B. Davidson, H. J. Schneider
43. Clinical governance 437
B. Higgs
44. Economic aspects of surgery 442
R. W. Hoile, G. Douglas
45. Statistical concepts: a tool for evidence-based
practice 445
/?. W. Morris
46. Critical reading of the literature 454
R. M. Kirk
47. Communication skills 458
R. M. Kirk, V. M. Macaulay
48. The surgical logbook 463
D. M. Baker
49. The MRCS examination 466
D. Wilkins
50. The intercollegiate examinations in surgery
472
R. E. C Collins
Index 475
XHI
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Resuscitation
/?. Touquet, P A Ward, M. W. Piatt J- A. Henry
Objectives
• Recognize the variety of presentations to
an accident and emergency (A & E)
department; these are often
multidisciplinary, complex, and neither
solely medical nor solely surgical.
• Understand the rationale for prioritizing
resuscitation sequences and basing
decisions on the patient's responses to
interventions.
• Follow protocols to avoid errors of omission.
• Understand arterial blood gases, both in
terms of acid-base balance and gas
exchange.
• Understand the difference between
oxygen tension (Pao 2 , partial pressure) and
oxygen saturation (Sao 2 ).
• Recognize that the doctor in A & E may be
the last generalist to manage the patient
before admission under a specialist team.
'Scientia vincit timorem'
(Knowledge conquers fear)
INTRODUCTION
Collapse (Latin col = together + lapsare = to slip; extreme
prostration, depression and circulatory failure) or coma
(Greek koma = deep sleep; unrousable loss of conscious-
ness) are features of diverse life-threatening conditions
depressing or injuring the central nervous system. The cause
is often unknown when the patient arrives in the resuscita-
tion room. Furthermore, there may be more than one
cause, for example a hypoglycaemic patient may fall and
sustain a head injury.
When a patient with an altered level of consciousness
arrives in the accident and emergency department, apply
the resuscitation sequence described in the American
College of Surgeons' Advanced Trauma Life Support
Course, whether the cause appears medical or surgical.
The initial sequence is the primary survey (ABCDE, see
below), a systematic assessment that can be performed
while undertaking any resuscitative procedures. Institute
ongoing monitoring of vital signs while observing their
response to any procedure undertaken, such as immedi-
ately infusing 2 litres of crystalloid into an adult with
hypovolaemic shock.
When the patient is stable, with clinically acceptable
vital signs, carry out the secondary survey, a thorough
examination from head to toe to avoid missing any patho-
logical condition. You are often the last doctor to carry out
a complete examination. If the patient needs to be trans-
ferred immediately to the operating theatre, the second-
ary survey must be carried out later, on the ward, by
members of the admitting team.
PART 1: PRIMARY SURVEY WITH
INITIAL RESUSCITATION
Greet and talk reassuringly to a conscious patient. Do not
treat the patient as an inanimate object. Take notice of the
history from the ambulance crew. Involve them in the
initial resuscitation and have them immediately available
to give any further details of the history. Ensure that the
ambulance transfer form is signed by a member of the
accident and emergency department staff.
The standard sequence of the initial primary survey is:
Airway, with cervical spine control
Breathing
Circulation
Disability - a brief neurological assessment
Exposure - undress the patient completely, but briefly, to
avoid hypothermia.
■■■>
Key points
Apply an appropriately sized cervical collar to
steady the head. In-line cervical spine
EMERGENCY
immobilization prevents iatrogenic (Greek iatros
= physician + gennaein = produce) spinal cord
damage in those with unsuspected neck injury.
• Be particularly careful if you pass an
orotracheal tube.
Airway
Assess
Talk to the patient; look for signs of confusion or agitation
which may indicate cerebral hypoxia. Listen for stridor or
gurgling sounds from a compromised airway Detect
expired warm air with your hand in a patient who is
breathing. Check if chest movements are adequate and
equal.
If the patient has inhaled smoke, look for carbon
deposits in the mouth or nostrils, which raise the possi-
bility of upper airway burns and associated carbon
monoxide poisoning. If so, call an anaesthetist to pass an
endotracheal tube.
Manage
Keep the airway open and clear it. Remove any foreign
bodies, such as sweets; suck out vomit. Lift the chin for-
wards to bring the tongue off the back of the naso-
pharynx. If the gag reflex is diminished, insert an oral
(Guedel) airway; if this is not tolerated, but obstruction is
still present, consider gently inserting a well-lubricated
nasopharyngeal airway. Do not insert a nasopharyngeal
airway if basal skull fracture is a possibility. Once the
airway is secured, deliver 10-15 1 min -1 oxygen through a
face mask with a reservoir device, which provides about
85% inspired oxygen.
None of these basic airway manoeuvres protects the
lungs from aspiration of gastric contents or blood. If the
patient has an absent gag reflex, insert a cuffed tracheal
tube by the oral or nasal route to facilitate efficient venti-
lation and protect the lungs.
If you cannot provide an airway in any other way,
urgently carry out a needle cricothyroidotomy followed,
if necessary, by a surgical cricothyroidotomy.
Breathing
Assess
Assess any cyanosis. If the neck veins are engorged, con-
sider the possibility of a tension pneumothorax, cardiac
tamponade, air embolus, pulmonary embolus or myo-
cardial contusion. Check the position of the trachea; if it is
deviated to one side, has it been pushed over by a tension
pneumothorax on the opposite side? Count the respir-
atory rate (normally 12-20 per minute) and expose, inspect
and palpate the anterior chest wall. Assess breath sounds
or their absence by auscultation. A severe asthmatic may
present with collapse and have a silent chest because with
extreme airway narrowing no air can move in or out of
the lungs. If three or more consecutive ribs are fractured
in two or more places, with a segment of paradoxical
chest wall motion, this is a flail chest. The underlying pul-
monary contusion may cause acute respiratory failure. If
there is any doubt about the adequacy of the patient's
airway or breathing, urgently obtain expert help from
physicians and anaesthetists.
Manage
Prevent hypoventilation, hypercapnia (Greek kapnos -
smoke, vapour - carbon dioxide) and cerebral vasodi-
latation. They produce increased intracerebral pressure
which is extremely dangerous in traumatized patients,
especially if they have suffered a head injury. Both adults
and children have a normal tidal volume of 7 ml kg -1 . A
patient with rapid, shallow breathing and signs of fatigue
and distress is unable to sustain a normal tidal volume.
Hypercapnia is likely, with a resultant increase in cerebral
perfusion and oedema. Institute assisted respiration,
initially by bag-valve-mask positive pressure ventilation.
An arterial blood sample demonstrates a high arterial
carbon dioxide tension (PaC0 2 ) level if breathing is inad-
equate. If possible, ventilate and oxygenate the hypoxic or
apnoeic patient for at least 3 min before attempting intu-
bation. Do not prolong any attempt for more than 30 s
before returning to bag-valve-mask ventilation. An
apnoeic patient needs urgent ventilatory support.
With assisted ventilation, aim to keep the arterial blood
oxygen above 10 kPa (80 rnmHg) and the carbon dioxide
below 55 kPa (40 rnmHg), but above 4 kPa (30 mmHg) to
prevent brain ischaemia. In a patient with head injury and
decreased consciousness, a reduction of the Paco2 to just
above 4 kPa (30 rnmHg) reduces cerebral oedema and intra-
cerebral acidosis.
Key points
• Assume that a spontaneously breathing patient
who is agitated, aggressive or with a
depressed level of consciousness, is hypoxic.
• Remember, though, that restlessness is also
caused by, for example, a full bladder or a tight
plaster of Paris splint.
Urgently take arterial blood samples from all collapsed
patients who are not likely to recover immediately, for
measurement of oxygen, carbon dioxide and acid-base
RESUSCITATION
1
^^^^^^d^^u
balance. Aspirate arterial blood from the radial artery or,
failing this, from the femoral artery, into a heparinized
syringe (a 2 ml syringe whose dead space has been filled
with heparin 1000 units ml -1 ).
Maintain arterial oxygen tension (Fao 2 ) above 10 kPa
(80 mmHg), with added inspired oxygen, to preserve
tissue viability. The exception is the patient with chronic
obstructive airways disease (COAD), who depends on
hypoxic drive rather than Paco 2 to breathe and will tend
to hypoventilate when given added oxygen of more than
35%. Diagnose this from the arterial blood gas, which
shows a high Paco 2 with a normal pH. Give all collapsed
patients high-flow oxygen initially, as patients whose res-
piration is dependent on hypoxic drive are uncommonly
encountered in A & E.
You may need to administer oxygen to produce a
higher than normal Pao 2 . In, for example, carbon monox-
ide poisoning, elevated pulmonary vascular resistance,
sickle cell crisis and anaerobic infections the treatment is
to produce an elevated Pao 2 .
Circulation
Assess
Assess the patient for shock.
Early signs of shock
• Anxiety, tachycardia of 100-120 min -1 ,
tachypnoea of 20-30 min \ skin mottling,
capillary refill time of more than 2 s r and
postural hypotension.
Initially assume hypovolaemia from occult bleeding if
there is postural hypotension with a fall of systolic blood
pressure of 20 mmHg, a fall of diastolic blood pressure
of 10 mmHg and a rise of pulse of 20 beats per minute
(20:10:20 rule). Supine systolic blood pressure does not
drop until an adult has lost around 1500-2000 ml of
blood, or 30-40% of the blood volume of 70 ml kg -1 body-
weight; by this time the patient is ashen in colour because
of blood-drained extremities.
The level of consciousness is also decreased because of
inadequate cerebral circulation, particularly if blood loss
was rapid. As a guide, a palpable carotid pulse indicates
a svstemic blood pressure of at least 60 mmHg.
Key point
If the carotid pulse is absent, initiate
immediate basic cardiopulmonary resuscitation
(CPR, see below).
Manage
Control haemorrhage from any external bleeding
points by direct pressure, with limb elevation where
appropriate.
1 . Intravenous access. The Parisian scientist Jean Poiseuille
(1797-1869) calculated that the rate of flow of fluid
through a pipe is proportional to the fourth power of the
radius, and inversely proportional to the length. In a
severely traumatized or hypovolaemic patient, never fail
to insert two short, wide-bore cannulae of 14 gauge or
larger, sited in peripheral veins, whether introduced per-
cutaneously or by surgical cutdown.
2. Venous cutdown. Acquire skill in this safe, simple and
quick technique for intravenous access. Prefer the saphe-
nous vein anterior to the medial malleolus or the basilic
vein in the elbow crease. Make a transverse, 2 cm incision
anterior to the medial malleolus or to the medial epi-
condyle of the humerus. Delineate, by blunt dissection,
the long saphenous or basilic vein. Ligate the vein distally
with 2/0 black silk. Control the vein proximally with a
similar loose ligature. Make a transverse incision across
one-third of the circumference of the vein to enable the
insertion of a 14- to 12-gauge cannula. Secure the cannula
in place by tightening the proximal suture. This technique
is applicable for collapsed infants.
3. Intraosseous infusion is an even simpler technique for
children under 7 years. In order to avoid the potential risk
of osteomyelitis, thoroughly clean the area around the
site of insertion, two fingers 7 breadth distal to the tibial
tuberosity, on the anteromedial tibial surface. Insert a spe-
cially designed intraosseous trocar and cannula through
the cortex of the bone into the marrow cavity. You may
slowly infuse crystalloid and colloid solutions into the
marrow (20 ml kg -1 initially for the collapsed child),
together with drugs used in resuscitation, with the excep-
tion of sodium bicarbonate and bretylium. The circulation
time from here to the heart is only 20 s.
4. Central venous cannulation, even in experienced
hands, may be dangerous for the trauma patient, who is
often restless. Such patients may not survive an iatrogenic
pneumothorax or a cervical spinal cord injury caused by
turning in the presence of an unsuspected neck injury; as
the above routes of access avoid the possibility of these
complications, they are to be preferred. Central venous
pressure monitoring is useful in the stabilized patient, but
these lines are not for resuscitation other than in patients
with cardiac arrest, when drugs should be administered
centrally. Carry out central vein cannulation after clean-
ing the area with antiseptic surgical solution.
a. Unless the patient has a head injury, apply a 20°
head-down tilt to fill the vein and reduce the risk of air
embolus. The easiest route for an anaesthetist is via the
right internal jugular vein, which provides the most direct
EMERGENCY
access to the right atrium. Turn the patient's head towards
the opposite side and you can feel the vein as the softest
part of the neck, usually lateral to the carotid artery in a
line from the mastoid process to the suprasternal notch.
The easiest route for you, or an accident and emergency
clinician, is probably through the right subclavian vein.
Pull the right arm caudaUy, to place the vein in the most
convenient relation to the clavicle for cannulation. Unless
there is a possibility of spinal injury, to improve access
place a sandbag beneath the upper thoracic spine so that
the shoulders lie more posteriorly.
b. For jugular vein cannulation, introduce the needle
through the skin at approximately the midpoint of a line
running from the mastoid process to the suprasternal
notch, aiming laterally at 30° to the skin, towards the right
big toe or right nipple, or towards the previously pal-
pated jugular vein. For subclavian vein access, introduce
the needle through the skin 2 cm inferior to the junction
of the lateral and middle thirds of the clavicle. Advance
the needle, aspirating continuously and snugging the
inferior bony surface of the clavicle, aiming at the supe-
rior aspect of the right sternoclavicular joint for not more
than 6 cm.
c. Aspirate until blood freely appears; ensure the bevel
of the needle is now directed caudally; remove the
syringe and immediately insert the Seldinger wire, flexi-
ble end first, through the needle. Remove the needle; rail-
road the plastic cannula over the Seldinger wire, then
remove the wire. Check that the cannula is in the central
vein by briefly allowing retrograde blood flow into the
attached intravenous giving set.
d. Aftercare: secure the line with a suture through the
skin and dress the wound with a sterile dressing. Return
the patient to the horizontal position and obtain a chest
X-ray to check the position of the central venous cannula
and to exclude a pneumothorax.
5. Correct hypovolemia by rapid intravenous infusion
of warmed crystalloid or colloid solutions followed by
blood. Rapid loss of more than 40% of a patient's blood
volume produces pulseless electrical activity, leading to
circulatory standstill unless you carry out immediate
resuscitation. You cannot measure the blood volume or
blood loss in the resuscitation room. Therefore monitor
the vital signs (delineated in Part 2), especially in
response to treatment such as fluid replacement, adjust-
ing your treatment accordingly
6. If the carotid pulse is impalpable, the heart has
become an ineffective pump and irreversible brain
damage results unless you take immediate action to
correct the specific causes of electromechanical dissoci-
ation, such as massive blood loss, tension pneumothorax
or cardiac tamponade. If there is no improvement or if
these conditions are not present, commence cardiac
massage for cardiac arrest (Fig. 1.1). Check the heart's
electrical rhythm on the monitor. Place the leads in the
correct positions as quickly as possible. If no rhythm is
visible, turn up the gain knob on the monitor and check
for a rhythm in two different ECG leads. Alternatively,
monitor through the paddles of a defibrillator, one placed
just to the left of the expected position of the apex beat
and one inferior to the right clavicle.
7. External chest compression. If you cannot feel the
carotid pulse after you have controlled ventilation, place
one hand over the other on the sternum, the lower border
of the hands being two fingers breadth above the
xiphisternal-sternal junction. If the hands are lower you
risk damaging the liver. Keep your arms straight, with the
shoulders in a direct line over the hands so that you do
not tire. Depress the sternum smoothly for 4-5 cm, at a
rate of 100 per minute, with a ratio of two ventilations to
fifteen compressions.
Key point
• The absence of a pneumothorax on this film
does not exclude the possibility of one
developing subsequently, possibly under
tension.
If direct venous access is not obtained during CPR, for
immediate drug therapy to the heart muscle give
drugs via a peripheral venous line, infusing 5% dex-
trose solution after injecting each drug, to flush it into
the central circulation. You may give certain drugs,
such as adrenaline (epinephrine), atropine, lidocaine
(lignocaine) and naloxone via the tracheal tube route,
in double the intravenous dosage.
Key point
• Do not interrupt cardiac massage for
ventilations.
Keep the compression rate regular. In this way the pres-
sure is increased generally in the chest both during com-
pression and by ventilation. In addition, the expanding
lungs drive the diaphragm down, leading to compression
of the vena cava, further facilitating the driving of blood
up the carotid arteries; this is the thoracic pump effect.
Feel for the carotid or femoral pulse every 2 min.
8. Diagnose the correct cardiac rhythm quickly. The
rhythm is ventricular fibrillation in 70% of patients with
non-traumatic cardiac arrest and the chance of successful
RESUSCITATION
1
Cardiac Arrest
IZ
Precordial thump
if appropriate
v
BLS algorithm
if appropriate
2
Attach
defib-monitor
C
VF/VT
Defibrillate x 3
as necessary
<=>
]
1
During CPR
Correct reversible causes
If not already:
* Check electrodes, paddle
position and contact
4 Attempt' verify:
airway & O^
intravenous access
• Give epinephrine every 3 min
Consider;
amiodarone, atropine/ pacing
buffers
Non-VF/VT
)
CPR 1 min
* 1 min if immediately
after defibrillation
Potential reversible causes:
Hypoxia
Hypovolemia
Hypo/hyperkalaemia and metabolic disorders
Hypothermia
Tension pneumothorax
Tamponade
Toxic/therapeutic disorders
Thrombo-embolic and mechanical obstruction
^^N^^^^^^^^^^^^^^^^^M
Fig. 1.1 Adult advanced life support. The Resuscitation Council (UK). Reproduced with permission.
resuscitation is directly proportional to the speed of
applying a DC shock in the correct manner and sequence
(Fig. 1.1). There must be no delay following arrest, and
this is why ambulance crews are being trained to use, and
are issued with, defibrillators.
9. Internal cardiac massage. External chest compression
does not effectively resuscitate an empty heart that is in
cardiac arrest from hypovolaemic shock; however inter-
nal cardiac massage is indicated in the A & E department
for direct penetrating trauma only. It is not for blunt
1 1
EMERGENCY
trauma, when the patient, at the very least, just has a
palpable pulse on arrival. When there is no appropriate
response to prompt rapid transfusion, consider internal
cardiac massage for penetrating trauma. This is the only
indication for an emergency thoracotomy for internal
cardiac massage by trained personnel in the A & E depart-
ment. If you have had appropriate training, it is both
safe and haemodynamically superior to external cardiac
massage, although the latter can be initiated without
delay and performed by non-surgeons. Open-chest cardio-
pulmonary resuscitation (CPR) enables you to feel and
see the heart, and direct electric defibrillation.
1 0. Create a left-sided thoracotomy through the fourth or
fifth intercostal space once the patient is receiving intermit-
tent positive pressure ventilation through a tracheal tube.
Immediately compress the heart using your left hand,
without at first opening the pericardial sac, by placing your
thumb over the left ventricle posteriorly and fingers anteri-
orly in front of the heart. Compress the heart at the rate of
100 times per minute, adjusting the force and rate to the
filling of the heart. Open the pericardium, avoiding the
phrenic and vagus nerves. You may inject adrenaline
(epinephrine), atropine and lidocaine (lignocaine), but
not sodium bicarbonate, directly into the left ventricle,
avoiding the coronary arteries. For internal defibrillation use
internal 6 cm paddle electrodes with saline-soaked gauze
pads and insulated handles. Place one paddle posteriorly
over the left ventricle and one over the anterior surface of the
heart (10-20 J).
11. Drugs. In a patient with cardiac arrest, if possible
give drugs such as adrenaline (epinephrine) centrally, and
for this reason become proficient in at least one method
of central venous cannula tion. Use the approach with
which you are most familiar. The infraclavicular approach
is often the most convenient and practicable means of
access.
Disability
This term signifies a brief neurological assessment you
must carry out at this stage of the initial examination. The
mnemonic used in the Advanced Trauma Life Support
Course is useful:
A = Alert
V = responds to Verbal stimuli
P ~ responds to Painful stimuli
U = Unresponsive
Now assess the presence or absence of orientation in time
(does the patient know the day and month?), space
(knows where he or she is?) and person (knows who he
or she is?). These perceptions are usually lost in this
sequence with lessening of consciousness. Alternatively
use the Glasgow coma scale at the outset.
Record the pupil size and response to light (Table 1.1).
Bilateral small pupils denote opiate poisoning unless dis-
proved by failure of naloxone to reverse the constriction.
If necessary, give up to 2 mg of naloxone (i.e. five vials of
0.4 mg). If there is a response, you may need to give more,
because naloxone has a short half-life. You may give it via
an endotracheal tube if you do not have intravenous
access. The other common cause of bilateral small pupils
is a pontine haemorrhage, for which there is no specific
treatment.
Expose
In a severely traumatized patient always carry out a
complete examination of the entire skin surface. Remove
every article of clothing. Carefully protect the spine.
Complete examination demands log-rolling by a mini-
mum of four trained people so that you can examine the
back. Perform this early if there is a specific indication,
such as injury to the posterior chest wall, or at the latest
at the end of the secondary survey. Protect all patients,
particularly children, from hypothermia.
Consider inserting a nasogastric tube or, if you suspect
a cribriform plate fracture, an orogastric tube. Insert a
urinary catheter after inspecting the perineum for bruis-
ing and bleeding, and carrying out a rectal examination
in an injured patient (see Ch. 2).
PART 2: MONITORING
Key point
Throughout the initial assessment, resuscitate,
monitor and react to changing clinical and vital
measurements (see also Ch. 9).
Pulse. Remember that in an elderly or even a middle-
aged person a rate of more than 140 beats per minute
is very unlikely to be sinus tachycardia as this is too fast
for someone of that age. Atrial flutter runs at around
300 beats per minute, and therefore if there is 2-1 atrio-
ventricular block the ventricular rate is 150 beats per
minute. The rate of supraventricular tachycardia is
usually 160-220 beats per minute.
Respiratory rate is important. Do not forget it. The
normal range is 12-20 breaths per minute. It rises early
with blood loss or hypoxia, and, as well as being a very
useful indication of the patient's clinical state, it is one
of the physiological parameters that is mandatory for
the calculation of the revised trauma score.
Blood pressure drops in hypovolaemia when the blood
loss is greater than 30-40% of the total blood volume -
8
RESUSCITATION
1
— a «M ^w s ^gM*ii ^ i tt^ atfc « a a feaaa^ :i ^i
Table 1.1 Pupil size and response to light in comatose patients
Dilated
One pupil
Both pupils
Atropine in eye
3rd nerve lesion normal consensual light
reflex, e.g. posterior communicating
artery aneurysm
Enlarging mass lesion above the tentorium,
causing a pressure cone
Optk nerve lesion:
Old; pale disc and afferent pupil
New: afferent pupil with normal disc, loss of direct
light reflex, loss of consensual reflex in other
eye - both constrict with light in other eye
Cerebral anoxia
Very poor outlook if increasing supratentorial
pressure - if dilated pupils preceded by unilateral
dilatation or if due to diffuse cerebral damage
Overdose: e.g. amphetamines {including MDMA
"Ecstasy")
carbon monoxide
phenothiazines
cocaine
glutethimide
antidepressants
Hypothermia
Constricted
Pilocarpine in eye
Horner's, e.g. brachial plexus lesion
Acute stroke uncommonly (brainstem
occlusion or carotid artery ischaemia: small
pupil opposite side to weakness)
Pilocarpine in both eyes (glaucoma treatment)
Opiates, organophosphate insecticides and
trichloroethanol (chloral)
Pontine haemorrhage or ischaemia (brisk tendon
reflexes, and raised temperature; poor
prognostic sign)
Alcohol poisoning (dilatation shaking)
(Macewan's pupil))
If pupils normal in size, and reacting to light, consider metabolic, systemic non-cerebral causes
(N,B. Normal pupiis do not exclude a drug overdose)
about 2000 ml in an adult. Fit young adults, and
especially children, maintain their blood pressure
resiliency, but then it falls precipitously when com-
pensatory mechanisms are overwhelmed.
Pulse pressure is the difference between systolic and
diastolic pressures. Diastolic pressure rises initially fol-
lowing haemorrhage / because of vasoconstriction from
circulating catecholamines. Systolic pressure stays con-
stant, therefore the pulse pressure decreases. This is fol-
lowed by a greater decrease in the pulse pressure as the
systolic blood pressure falls once 30% of the patient's
blood volume has been lost.
Capillary refill time is the period it takes for blood to
return to a compressed nailbed on release of pressure.
It may be lengthened by hypothermia, peripheral
microvascular disease and collagen diseases, in addi-
tion to hypovolemia. The normal value is 2 s, but this
increases early in shock, following a 15% loss of blood
volume.
Temperature fall indicates the degree of blood loss in a
hypovolemic patient, quite apart from primary
hypothermia. Restore blood volume adequately
because simple warming of a hypovolaemic patient
produces vasodilatation with resulting further fall in
blood pressure. A patient with primary hypothermia is
usually also hypovolaemic, so rapid rewarming results
in a drop in blood pressure unless blood volume is
replaced. Ensure your resuscitation room has a
warming device, ideally as part of a rapid transfuser, so
that intravenous fluid at 37-38°C can be immediately
infused to the hypovolaemic or hypothermic patient.
• Urinary output. The minimum normal obligatory
output is 30 ml h _1 . In a child it is easily remembered as
1 ml kg" 1 h" 1 . Suspect renal pathology if you find more
than a trace of +protein on stick testing.
• Central venous pressure (CVP) is measured in centime-
tres of water by positioning the manometer on a stand
such that the zero point is level with the patient's right
atrium. The normal pressure is around 5 cmH 2 from
the angle of Louis, with the patient at 45° to the
horizontal.
The CVP is a measure of the filling pressure (preload) to
the right atrium. It reflects the volume of blood in the
EMERGENCY
**pUitUferilMHAillrtMUb
central veins relative to the venous tone. It is not a
measure of left heart function, until right ventricular func-
tion is compromised as a result of poor left heart function.
It may be low if the patient is hypovolaemic, and rises to
normal with correction. If it rises slowly with a fluid chal-
lenge, this usually indicates hypovolaemia. Particularly in
the young, peripheral vasoconstriction to conserve central
blood volume occurs in the presence of hypovolaemic
shock, maintaining central venous pressure to a limited
degree. It is raised if the circulating volume is too large,
as might happen with renal failure or with overtransfu-
sion. Overtransfusion not only precipitates heart failure,
due to dilatation of the heart, but in a patient with a head
injury the resultant rise in intracranial pressure may cause
irreversible damage to the already bruised brain.
Therefore assiduously monitor the CVP in these circum-
stances.
The CVP also rises with malfunctioning of the right
side of the heart. It cannot then be used as an indicator of
systemic circulatory filling, except as a measure of chang-
ing cardiac function. It may be raised for mechanical
reasons, such as tension pneumothorax or cardiac tam-
ponade. It is also raised in the presence of pulmonary
embolism, or when the heart is failing for lack of muscu-
lar power due to contusion or infarction.
Arterial blood gases
pH (normal range 7.35-7.45)
Does the patient have an acidosis, alkalosis or neither
(Table 1.2)? The lower the pH, the more acidic is the blood
sample, the opposite being the case for alkalosis. Acid (as
hydrogen ions) is produced continually from metaboliz-
ing cells, mostly as carbon dioxide. More is generated by
lactic acid production during conditions of hypoxia, for
example in shock, or in cardiac or respiratory arrest.
Inadequate tissue perfusion results in acid buildup. Most
acid-base abnormalities result from an imbalance
between production and removal of H + ions (Table 1.3).
Hydrogen is adsorbed by buffers, the largest being pro-
teins, both intra- and extracellularly. In the extracellular
fluid, the largest buffer is haemoglobin. However, bicar-
bonate is a highly dynamic buffer, enabling an exchange
to occur between hydrogen and carbon dioxide. This
enables hydrogen to be excreted rapidly via the lungs as
carbon dioxide:
H + + HCOi ±? H 2 C0 3 ±? C0 2 + H 2
Hydrogen ions are also excreted via the kidneys, but over
hours or days, leaving respiratory compensation to be the
most rapid method the body has for correction.
The complex proteins of the body are optimally con-
formed at ideal pH. When the pH of tissues changes, it
induces conformational changes in proteins, affecting
their function, especially enzymes and cell membrane
channels. This is why it is crucial to maintain normal pH.
Carbon dioxide is the largest generator of H + ions, ten
times more than the production of lactic or other
metabolic acids (Table 1.3).
Pco 2 (normal range 35-45 mmHg, 4.5-5.5 kPa)
• Pco 2 is high: suggests a respiratory acidosis (if pH is
low); or a compensated metabolic alkalosis (see below).
• Pco 2 is low: suggests a respiratory alkalosis (if pH is
high); or a compensated metabolic acidosis (see below).
The partial pressure of carbon dioxide is related to the
degree of lung ventilation. Hyperventilation reduces
Pco 2 and vice versa. If the patient is not breathing ade-
quately, carbon dioxide is not adequately excreted and
hydrogen ions build up, leading to acidosis caused by
inadequate ventilation, that is, a respiratory acidosis. pH
falls, indicating acidosis. Anxious patients and those in
early hypovolaemic shock have a tachypnoea, resulting in
overexcretion of carbon dioxide, with loss of hydrogen
and a resulting respiratory alkalosis.
When the patient is ventilated mechanically or manu-
ally, an end-tidal carbon dioxide measuring device gives
r"
Table 1.2 Reading of arterial blood gases for acid-base balance
Acidosis or alkalosis?
Respiratory component?
Metabolic component?
pH 7.35-7.45
If Pco 2 < 4.5 kPa, suggests respiratory alkalosis (pH > 7.45) r or attempted
compensation of a metabolic acidosis (pH < 7.35 and BE < -3)
If Pco ? > 5.5 kPa r suggests respiratory acidosis (pH < 7.35), or attempted
compensation of a metabolic alkalosis (pH > 7 45 and BE > + 3)
Base excess (BE) >s always affected by metabolic acid-base changes:
Metabolic acidosis causes BE < -3
Metabolic alkalosis causes BE > +3
10
RESUSCITATION
1
Table 1.3 Production a
rtd elimination of hydrogen ions
J
Clas:
Daily production
Source Excreted in Metabolic
Normal organ of
(mol)
breath removal
elimination
possible
1
CO 2
15
Tissue respiration +
Lungs
11
Organic acids and
urea synthesis
Lactic
1.2
Muscle, brain - +
erythrocytes, skin, etc.
Liver (50%),
kidneys, heart
Many tissues (not fiver)
Hydroxy butyric and
0.6*
Liver - +
aceto acetic
Fatty free acids
0.7
Adipose tissue - +
Most tissues
(FFA)
H + generated during
1.1 f
Liver — +
Most tissues (see te*t) r
urea synthesis
small fraction in urine
111
Fixed acids'
Sulphuric
Dietary sulphur-containing *i
►
0.1
amino acids
Urinary excretion
Phosphoric
Organic phosphate
h
(partly)
metabolism J
i
The
daily production rates for the organic acids are calculated from results obtained in a resting 70 kg man after an overnight
fast,
and are proportioned
up to 2A h values.
* Because of ingestion of food during daytime
and consequent suppression of FFA and ketone body production, the values for
these acids may be conside
rable overestimates
,
'On
100 g protein diet.
a good correlation of arterial carbon dioxide, unless there
is significant lung disease. End-tidal carbon dioxide
partial pressure reflects that in the pulmonary artery, and
indicates correct siting of the tracheal tube.
Base excess (or deficit) (normal range -3 to
+3)
• High negative value: (e.g. -10) always indicates a
metabolic acidosis. pH tends to normalize because of
hyperventilation to reduce PaC0 2/ producing a com-
pensatory 'respiratory alkalosis'.
• High positive value: (e.g. +10) always indicates a
metabolic alkalosis. Similarly, hypoventilation to increase
Paco 2 tends to compensate and normalizes the pH.
A metabolic acidosis indicates an inability of the kidneys
to shift an increased hydrogen load, as occurs in shock,
diabetes or renal failure.
Chronic respiratory acidosis with normal pH occurs in
chronic lung disease associated with chronic hypercar-
bia, causing the kidneys to retain bicarbonate ion. This
produces an increase in plasma bicarbonate concentra-
tion and a normalizing of blood pH, despite the hyper-
carbia (metabolic compensation). These changes take
several days to occur but will identify those patients
who normally run high PaC0 2 levels, not just those with
acute changes. Whenever there is an attempted com-
pensation, the pH never quite reaches completely
normal values, which is how you can tell if there has
been compensation.
Overenthusiastic treatment with sodium bicarbonate is
hazardous (Table 1.4). Do not give bicarbonate during the
first 15 min of a cardiac arrest in a previously healthy
patient. The principal method of controlling acid-base
status during a cardiorespiratory arrest is adequate ven-
tilation to ensure carbon dioxide excretion. If the pH is
below 7.1 at 15 min with a normal or low Pco 2 , give either
50 ml of 8.4% sodium bicarbonate intravenously (1 ml =
1 mmol) or calculate the amount of bicarbonate needed to
correct the metabolic acidosis from the blood gas result.
Multiply the base deficit by the estimated extracellular
volume (divide the product of the patient's weight in kilo-
grams and the base deficit by 3). Base deficit is defined as
the millimoles of alkali required to restore the pH of 1 litre
of the patient's blood to normal at Pco 2 = 5.33 kPa. In
practice, do not normally give more than 1 mmol kg^ 1
initially. Of paramount importance in the traumatized
11
1 1
EMERGENCY
Table 1-4 Hazards of bicarbonate therapy
1,
4,
Inactivates simultaneously administered catecholamines
Shifts the oxyhaemoglobin dissociation curve to the left, inhibiting the release of oxygen to the tissues
Exacerbates central venous acidoses and may, by production of carbon dioxide, produce a paradoxical acidosis
Induces Hypernatremia, hyperosmolarity and an extracellular alkalosis; the last causes an acute intracellular
shift of potassium and a decreased plasma ionized calcium
patient is restoration of blood volume and reperfusion of
the tissues.
A lowered pH is desirable, provided that it does not fall
below 7.1. Correct it if it falls below this; further acidosis
lowers the threshold of the heart to ventricular fibrillation
and inhibits normal cell metabolism.
Pao 2 and oxygen saturation
The partial pressure of oxygen in the arterial blood (also
called the oxygen tension) is that pressure which oxygen
gas produces if it is in a gaseous phase - if the blood is in
a glass vessel with a gaseous phase immediately above it.
Gases move down pressure gradients, and so oxygen in
the body always moves from an area of higher partial
pressure to an area of lower pressure, for example, from
lung alveoli to mixed venous blood in the pulmonary
artery. The Pao 2 indicates the amount of oxygen reaching
the arterial blood from the lungs, or shows if there is some
dilution with venous blood by shunting.
Oxygen saturation is the proportion of haemoglobin
bound to oxygen, expressed as a percentage. Oxygen car-
riage depends on haemoglobin, and haemoglobin-bound
oxygen is the main supplier of the tissues. The amount of
oxygen in solution in the blood is minute, becoming sig-
nificant only at ambient pressures which are multiples of
atmospheric pressure. This is demonstrated in the oxygen
flux equation, which gives the amount of oxygen flowing
to the tissues per minute:
2 flux = CO [(Sao 2 x Hb x 1 .34) + f]
where CO is the cardiac output, Sa0 2 is the arterial oxygen
saturation, 1.34 is Hoeffner's constant (the amount of
oxygen that is capable of combining with Hb) and F is
the small amount of oxygen dissolved in the blood. The
values are converted to give millilitres per minute:
normal oxygen flux is 1000 ml min -1 . The minimum flux
compatible with life is 400 ml min -1 .
Oxygen saturation is now routinely measured non-
invasively by shining several infrared wavelengths of
light across a finger, earlobe or other piece of skin. A
sensor detects those waves not absorbed by haemoglobin.
Oxy haemoglobin and deoxyhaemoglobin have different
infrared absorption spectra, so the machine can calculate
the mean oxygen saturation of blood reaching the part
with each pulse, compensating for tissue absorption by an
algorithm.
The relationship between Pao 2 and Sao 2 is shown in the
oxygen dissociation curve (Fig. 1.2). Note how the curve
becomes steep below 90% saturation - the situation for
many patients with lung disease.
This curve is calculated for HbA, with normal charac-
teristics. Other haemoglobins produce curves in different
positions. For example, sickle cell anaemia shows a
marked shift to the right, and fetal haemoglobin is shifted
to the left.
Acidosis increases ease of unloading oxygen from the
blood into tissues; this is the Bohr effect, described by the
Danish physiologist Christian Bohr (1855-1911), of pH on
the oxygen dissociation curve (Fig. 1.2). Increasing tem-
perature and increasing partial pressure of carbon dioxide
have the same effect, the latter not just because of an asso-
ciated acidosis but also because carbon dioxide combines
directly with haemoglobin to form carbamino com-
pounds. Anaemia, heat, raised carbon dioxide, acidosis
and increased 2,3-diphosphoglycerate (2,3-DPG) cause a
rightward shift to the oxygen dissociation curve, the
opposite effects producing a leftward shift.
40 60 80 100
Oxygen pressure mm Hg
Fig. 1.2 Effect of pH on the oxyhaemoglobin
dissociation curve of human blood at 38°C.
12
RESUSCITATION
1
Blood sugar (fasting blood glucose normal
range 3.6-5.8 mm I" 1 )
Key point
Order an immediate blood glucose estimation,
using a reagent strip, on every patient who has
an altered level of consciousness, otherwise
you will miss hypoglycaemia.
Follow this with a laboratory estimation. When giving
glucose in A & E, be aware of the possibility of precipi-
tating Wernicke's encephalopathy (confusion, ophthal-
moplegia, nystagmus, ataxia and peripheral neuritis -
described in 1881), and give B vitamins (Pabrinex) intra-
venously at the same time if there is any evidence of
alcohol misuse.
PART 3: THE SECONDARY SURVEY:
DETERMINING THE CAUSE OF THE
PATIENT'S COLLAPSE
After carrying out the initial assessment (primary survey)
and resuscitation of a collapsed patient presenting to the
A & E department with no history, a deceptively incom-
plete history or, worse, an incorrect history, now proceed
to make a full head-to-toe examination. This is the sec-
ondary survey, during which you aim to gain a clearer
picture of the cause of the patient's collapse. Ensure that
there is no occult injury. Examine all the skin, including
the mouth and throat, the external auditory meati and the
perineum. Always consider all the forensic possibilities,
noting needle marks, pressure blisters and the presence of
any visible soft tissue injuries. Remember that bruising
may appear at a distance from the site of injury.
1. Follow a routine to ensure you do not omit any
feature. Keep in mind the common causes of collapse
(Tables 1.5, 1.6), especially if communication is difficult,
because of language, because the patient is unconscious
or cannot communicate, or when obvious initial clinical
signs deflect you from finding the hidden life-threatening
pathology.
2. Strictly adhere to standard guidelines for protection
of medical and nursing staff from contamination with
body fluids: wear gloves, waterproof gowns and masks
with visors. Take special care to avoid needlestick
injuries. Ensure all staff are immunized against hepatitis
B virus.
3. Leave on the cervical collar in all trauma patients
while they are in the resuscitation room. This is manda-
tory for all patients who have evidence of trauma above
the level of the clavicle and have any decrease in level of
consciousness, whether it be from the trauma itself or
from drugs, especially alcohol.
4. Keep an open mind to all diagnostic possibilities
while both collecting the clinical evidence and monitoring
the response of the vital signs to treatment. Beware a
patient found by the police, and smelling of alcohol, who
develops an acute intracranial haematoma after a rela-
tively trivial head injury Involve your anaesthetist early
with preparation for the CT scan of brain and possibly
cervical spine. Patients with a head injury who misuse
alcohol may have a larger subdural space and prolonged
clotting times. Patients taking aspirin or warfarin are also
at risk.
5. If the conscious level is reduced and the gag reflex is
depressed, the patient cannot protect his or her own
airway. Call for anaesthetic assistance immediately.
Provided he or she is breathing spontaneously, place the
patient in the recovery position on the side (ensure first
there is no evidence whatever of a spinal injury).
Otherwise immediate preparations must be made to intu-
bate the trachea in order to protect the lungs. This also
applies if the patient is to receive gastric lavage and
cannot protect his or her own airway with complete cer-
tainty. If gastric contents are aspirated into the lungs they
must be promptly sucked out because they produce a
chemical pneumonitis followed by bacterial pneumonia.
The clinical picture may well develop into adult respir-
atory distress syndrome (ARDS).
6. Consider forensic possibilities (Latin forum = market
place, where courts of law were held; the application of
medical science to elucidating appropriate legal ques-
tions). Look for needle marks, soft tissue injuries and
bruising, which may appear at a distance from the site of
injury. Remember the possibility of non-accidental injury
in children and in the elderly.
7. Rhabdomyolysis and myoglobinuria may develop in
any comatose patient after prolonged tissue pressure and
muscle ischaemia, which is then relieved. Local swelling
of muscles may be evident and compartment syndromes
can develop because of positional obstruction of the cir-
culation. Muscle death starts after 4h of complete
ischaemia. Look for the early symptoms and signs of pain
and paraesthesiae in a pallid, cool, weak limb. Passively
extend the fingers or flex the foot to test for a developing
compartment syndrome (anterior tibial compartment
syndrome is the commonest). Losses of distal pulses,
numbness, paralysis and development of a flexion con-
tracture are all late signs. With myoglobinuria ensure that
the urinary output is maintained at over 100 ml h _1 in an
adult, or 2 ml kg -1 h" 1 in a child. Alkalinization of the
urine in an appropriate high dependency setting with
adequate monitoring increases the excretion of myo-
globin, and will help prevent renal failure.
13
EMERGENCY
Table 1 .5 Synopsis of causes of collapse to be considered during secondary survey
System
Cardiac
Vascular
Diagnosis
Respiratory Upper airway obstruction
Ventilatory failure
Failure of alveolar gas exchange
Tension pneumothorax
Ventricular fibrillation
Asystole
Pulseless electrical activity
Cardiogenic shock or failure
Hypovolemic shock
Anaphylactic shock
Dissecting thoracic aorta
Leaking abdominal aortic
aneurysm
Septic Shock
Neurogenic shock
Gastrointestinal Haemorrhage
Perforated peptic ulcer
Pancreatitis
Mesenteric embolism
Gynaecological Ruptured ectopic pregnancy
Obstetric
Supine hypotension
Edarnpsra
Pulmonary embolism
Amniotic fluid embolism
Notes
InhaJed foreign body (try Heimlich manoeuvre)
Infection such as epiglottitis (occurs in aduits, although
commoner in children)
Call help urgently
Trauma including respiratory burns
Asthma
Chest trauma such as sucking open wound
Paralysis such as in Guillain-Barre syndrome
Pneumonia
Pulmonary contusions
Cardiogenic pulmonary oedema
Adult respiratory distress syndrome
From trauma (including iatrogenic)
Ruptured emphysematous bulla
Follow Resuscitation Council (UK) guidelines for treatment
of cardiac arrest
Look for treatable cause; tension pneumothorax, cardiac
tamponade, hypoxia or hypovolemia, drug overdose
Acute myocardial infarct
Arrhythmia
Pulmonary embolism
Cardiac contusions after blunt chest trauma
Valve rupture
Revealed or concealed haemorrhage
Diarrhoea and vomiting
Fistulae
Heat exhaustion
From stings and bites, drugs or iodine-containing contrast
used for radiological investigation
Usually in previously hypertensive patients, pain radiates
to back
Always check femoral pulses so that you consider aortic
pathology (although pulses may not be lost)
Initially massive peripheral vasodilatation: 'warm shock'.
Temperature may be normal
From loss of sympathetic vascular tone in cervical or high
thoracic spinal cord injury
Always check: serum amylase
Abdominal signs may be absent initially
Usually at 4-6 weeks gestation. Always think of diagnosis
in collapsed young woman
The gravid uterus obstructs venous return from the vena
cava unless the pregnant woman is turned onto her left side
14
RESUSCITATION
1
Table 1.5 (cont'd)
System
Diagnosis
Neurological Head injury
Infection
Cerebrovascular
Epilepsy
Poisoning
Alcohol
Haematological Sickle cell crisis
Malaria
Coagulopathy
Metabolic
Hypoglycaemia
Hyperglycaemia
Hyponatremia
Hypocalcaemia
Hepatic failure
Renal failure
Endocrine
Hypothermia
Addisonian crisis
Myxoedema
Notes
Isolated head injuries do not cause shock in adults. Look for
sites of blood loss elsewhere
Meningitis in children (often meningococcal in UK), tetanus,
botulism, pofiornyelitis, rabies
intracranial embolism or haemorrhage
Subarachnoid haemorrhage may present solely as a severe
headache
Including the postictal (following a seizure) state
See Table 16
May lead to respiratory failure
Cerebral malaria causes coma
Thrombocytopenia may present with bleeding
Check blood glucose in every patient
Coma may be first presentation of diabetes mellitus
May be addisonian crisis
May present with fits
Precipitated by paracetamol overdose in previously fit
people, and by intestinal haemorrhage, drugs, or high-
protein diet in those with chronic liver disease
Prerenal from dehydration
Renal, e,g, from crush syndrome and myoglobinuria
Post-renal from ureteric obstruction (dangerous
hyperkalemia causes tall tented T waves and widening of
the QRS complexes)
Resuscitation may include passive or active core rewarming
Sepsis and hypovolemia often coexist
Give 200 mg hydrocortisone i.v. (hypotension, low serum
sodium, raised serum potassium)
Always consider in hypothermic patients
Ta b I e 1 . 6 Co m mon d r ugs
and poisons
Drug
Symptoms and signs
Treatment
Paracetamol
Liver and renal failure, hypoglycaemia
Charcoal
May be asymptomatic initially
Acetylcysteine
Salicylates
Tinnitus, abdominal pain
Lavage and charcoal
Vomiting, hypoglycaemia, hyperthermia,
Rehydration
sweating
Urinary alkalinization
Acid-base disturbances
Haemodia lysis
Tricyclic antidepressants
Arrhythmias and hypotension
Lavage and charcoal
Dilated pupils, convulsions
Cardiopulmonary support
Coma
Sodium bicarbonate
Benzodiazepines
Drowsiness or coma
Respiratory support
Respiratory depression
(Flumazenil)
Opioids (heroin)
Pinpoint pupils
Respiratory support
Loss of consciousness
Naloxone
Respiratory depression
Needle marks
15
EMERGENCY
Table 1.6 (cont'd)
Drug
Symptoms and signs
Treatment
Phenothiazines
Dyskinesia, torticollis
Procyclidine
Lidocaine (lignocaine)
Tingling tongue
Cardiopulmonary support
Perioral paraesthesiae
Diazepam for convulsions
Convulsions
Ventricular fibrillation
Carbon monoxide
Nausea and vomiting
Headache, drowsiness
Hallucinations, convulsions
100% or hyperbaric oxygen
Cyanide
Headache, vomiting, weakness
Amyl nitrite inhalation
Tachypnoea, convulsions
Dicobalt edetate i.v. if diagnosis certain
Coma
Iron
Hypotension, vasodilatation
Lavage
Gastric haemorrhage
Desferrioxamine
Organophosphates
Nausea, vomiting, diarrhoea
Lavage
(pesticides, nerve gases)
Salivation, pulmonary oedema
Atropine
Pinpoint pupils, convulsions, coma
Pyridostigmine
8. Keep clear, precise medical records of any resuscita-
tion sequence, remembering that, since 1 November 1991,
patients or their relatives have had the legal right to see
medical records. This record keeping is the responsibility
of the senior doctor present. Take appropriate care with
forensic evidence, especially from terrorist incidents —
anything removed from victims must be removed by a
named person and must also be handed to a named
person who personally seals the item in a labelled bag.
Key point
• If there is any clinical deterioration return to
the basic initial sequence of the primary survey
and recheck AIRWAY, BREATHING, CIRCULATION
yet again.
9. Ensure all patients with a diminished level of con-
sciousness are seen by an anaesthetist before they leave
the A & E department. Patients must be in the best poss-
ible clinically supported condition for transportation,
whether their journey is to the CT scanner, to a ward or
to another hospital. If necessary, ensure that the patient is
ventilated, depending on the length of journey and the
form of transport employed. Order an appropriate
trained attendant, such as an anaesthetist.
10. Do not allow the patient to leave the A & E depart-
ment without stable vital signs, appropriate intravenous
lines in place, and having been thoroughly examined,
unless there is an acceptable reason. A patient may all too
easily deteriorate clinically in the X-ray room or, even
more dangerously by reasons of reduced space, in the CT
scanner. There must at the very least be a doctor of regis-
trar grade in command of the resuscitation team.
11 . For an A & E department to receive patients who
need immediate resuscitation from a 'blue-light' ambu-
lance, the hospital must have a minimum of an anaes-
thetic registrar, a medical registrar and a surgical registrar
'living in' on site 24 hours a day Even if the patient does
not survive, you will be able to tell the relatives truthfully
that everything possible was done.
12. Both medical audit and medicolegal considerations
dictate the above minimal adequate standards of care. All
doctors who are expected to resuscitate the collapsed
patient as part of their work practice are expected to be
trained in the above. This is your responsibility, but more
especially that of the supervising consultant and above all
of the employing authority.
16
RESUSCITATION
1
Summary
• Do you understand the importance of
following routines and protocols when
examining and treating collapsed patients?
• Can you perform a competent initial
primary survey, and identify and perform
appropriate resuscitation procedures?
• Are you capable of setting up monitoring
procedures, interpreting the findings and
taking the correct actions?
• Do you have a grasp of the basic sciences
as regards normal and altered body
functions?
• Can you carry out a complete, thorough,
secondary survey and interpret the
features?
• Are you aware of the forensic aspects of
working in the accident and emergency
department?
Further reading
Advanced Life Support Course Sub-Committee 2000 Advanced
life support course provider manual 4th edn. Resuscitation
Council UK
Advanced Life Support Group 1997 Advanced paediatric life
support, 2nd edn. BMJ Publishing Group, London
Advanced Trauma Life Support Course Manual 1997 American
College of Surgeons, Chicago IL
Driscoll P, Gwinnutt C, Jimmerson CL, Good all O 1993 Trauma
resuscitation. Macmillan, London
Driscoll P, Brown T, Gwinnutt C, Wardle T 1997 A simple guide
to blood gas analysis. BMJ Publishing Group, London
Evans TR 1995 ABC of resuscitation. British Medical
Association, London
Henry J A 1997 Poisoning. In: Skinner D, Swain A, Peyton R,
Robertson C (eds) Cambridge textbook of accident and
emergency. Cambridge University Press, Cambridge
Jones RM 1989 Drug therapy in cardiopulmonary resuscitation.
In: Baskett PJF (ed.) Cardiopulmonary resuscitation. Elsevier,
Amsterdam, pp 99-101
Royal College of Physicians 1991 Some aspects of the medical
management of casualties of the Gulf War. RCP, London
Skinner D, Driscoll P, Earlam R 1996 ABC of major trauma.
British Medical Journal, London
Touquet R, Fothergill J, Henry JA, Harris NH (2000) Accident
and emergency medicine. In: Powers MJ, Harris NH (eds)
Medical negligence, 3rd edn. Butterworths, London
APPENDIX: CHEMICAL WEAPONS
Terrorist or military attacks with chemical weapons may
result in pathology and panic. Here we describe the
effects of nerve gas and mustard gas.
Nerve gases such as sarin, tabun
These are organophosphorus compounds that act by
inhibiting the enzyme acetylcholinesterase and therefore
preventing the breakdown of acetylcholine at motor end-
plates. The symptoms and signs of poisoning are the same
as for organophosphorus insecticide poisoning - over-
activity of the parasympathetic system and paralysis of
the muscles of respiration.
Initially treat by reversing the effects of acetylcholine at
muscarinic receptors, using atropine. Give 2 mg intra-
venously every 10-15 min in severe poisoning. Support
respiration, reactivate inhibited acetylcholinesterase with
oximes (pralidoxime mesilate) and suppress convulsions
with diazepam. Pretreatment with pyridostigmine
(reversible inhibitor of acetylcholinesterase) protects a
proportion of the total quantity of enzyme present against
a subsequent attack by nerve gas.
Mustard gas (sulphur mustard)
Exposure to the liquid or vapour produces blistering of
the skin and damage to the cornea and conjunctiva.
Classically there is an asymptomatic latent period of up
to 6 h before reddening of the skin develops, leading to
blistering. Burns are initially superficial, and blister fluid
does not contain free sulphur mustard. Early vigorous
scrubbing of the skin with soap and water reduces the
severity of the skin burns.
Treat eye exposure with saline irrigations, mydriatics,
Vaseline to prevent sticking of the eyelids, dark glasses
and antibiotic drops. The damage usually resolves over a
number of weeks.
Inhalation produces damage to the upper respiratory
tract, with sloughing of the epithelium of the airways and
nasal passages. The most severely affected patients need
assisted ventilation with oxygen. Absorption of sulphur
mustard leads to depression of the bone marrow and a fall
in the white count, with a maximum effect at about 2
weeks post-exposure.
In the First World War the death rate from mustard gas
was 2% of those exposed, resulting from burns, respir-
atory damage and bone marrow depression.
17
Trauma
M. Smith, P. A Driscoll
Objectives
Describe the biomechanics of injury
commonly seen in clinical practice.
Revise those aspects of human anatomy
important in trauma care.
Discuss the normal and pathophysiological
response to trauma.
Quantify trauma severity by using the
anatomical and physiological assessments.
Trauma is a major cause of death in the UK. It is sur-
passed only by ischaemic heart disease, respiratory
disease and carcinoma. Irrespective of gender it is the
leading cause of death in the first four decades. Trauma
accounts for 8.3% of all potential years lost under age 75.
In England and Wales, approximately 10 000 people die
each year: just under half of these deaths result from road
traffic accidents; a not dissimilar number occur in the
home.
There has been a gradual fall in the number of UK
deaths and serious injuries following trauma. This is due
to primary, secondary and tertiary injury prevention,
illustrated for road traffic accidents (RTA) in Table 2.1.
Between 1974 and 2000 the number of fatalities fell by
49% to 3409, and the number of seriously injured by 56%
to 41 564. In contrast, the number of minor injuries rose
by around 35% to 320 283.
It is estimated that for every trauma death 2-3 victims
are disabled, a proportion of whom require continuing
healthcare facilities for life. The cost to the NHS and social
service budgets could exceed £1.2 billion (Department of
Health 1998); the cost to the country's economy is con-
siderably greater.
Trimodal distribution of death following
trauma
Over a decade ago, Trunkey, an American pioneer in
the study of trauma, showed that trauma deaths in
San Francisco followed a trimodal distribution over time.
1. The first peak occurs at, or shortly after, the injury;
these patients die from major neurological or vascular
injury, most being unsalvageable with current technology.
Key point
• Up to 40% of irrecoverable trauma deaths may
be avoided by appropriate prevention
programmes.
2. The second peak occurs several hours after the
injury. Patients commonly die from airway, breathing or
circulatory problems and many are potentially treatable.
Table 2.1
Initiatives in reducing RTA trauma
initiative
Definition
Examples
Primary
Prevents the RTA occurring
Better roads, speed restrictions, better car brakes, drink
driving legislation
Secondary
Reduces the effect of the collision
Seat belts, air bags, pedestrian-friendly' cars
Tertiary
Improvements in medical care
Speedy and effective resuscitation,
integrated trauma care, early rehabilitation.
18
TRAUMA
2
This period is known as the 'golden hour', emphasizing
the time following injury when it is critical to resuscitate
and stabilize patients.
3. The final peak occurs days or weeks following injury.
These victims die from multisystem organ failure (MSOF)
or sepsis syndrome. Suboptimal resuscitation in the
immediate or early postinjury phase increases the inci-
dence of mortality and morbidity during this phase.
The relative sizes of these peaks are now known to vary
depending on the country. In Scotland, the first peak
accounts for 76% of all the trauma deaths, the second 7%
and the third 17%. This contrasts with San Francisco's
figures of 50%, 30% and 20%, respectively. Indeed, recent
work questions the existence of the trimodal distribution
of death in the UK, suggesting an early peak followed by
an exponential decline in mortality over time.
BIOMECHANICS OF INJURY
BLUNT TRAUMA
Over 90% of trauma in the UK is a result of a blunt mech-
anism. The force is dissipated over a wide area, minimiz-
ing the energy transfer at any one spot and so reducing
tissue damage. In low energy impacts, the clinical conse-
quences are dependent on the organs involved. In con-
trast, when high energies are involved, considerable
tissue disruption can be produced, irrespective of the
underlying organs. There are three types of force:
1. Shearing results from two forces acting in opposite
directions. Skin lacerations and abrasions produced by
shear tend to be irregular, have a higher risk of infection
and are associated with more damage to the surrounding
tissue and more excessive scarring than follows low energy
penetrating trauma. Shearing forces have a maximal effect
on abdominal viscera at the points where the organs are
tethered. Common examples include the peritoneal attach-
ments at the duodenojejunal flexure, spleen, ileocaecal
junction and the vascular attachments of the liver.
2. Tension occurs when a force acts on a tissue surface
at an angle of less than 90 s , causing avulsions and flap for-
mation. Both are associated with more tissue damage and
necrosis than are found after a shearing force.
3. Compression acts on a tissue surface at 90 s and can
produce significant damage and necrosis of the underly-
ing structures. The impact site usually shows contusion
(Latin tundere - to bruise), haematoma if a significant
number of blood vessels are damaged, and possibly a
breach of the surface tissue. Additionally, compression
forces may raise internal pressure sufficiently to rupture
the outer layer of closed gas or liquid-filled organs such
as the bowel.
A combination of these forces frequently contributes to
the pattern of injury seen in victims of blunt trauma.
Typically, multiple injuries occur, one system usually being
severely affected and one to two others damaged to a
lesser degree. Overall, the UK incidence of life-threatening
injuries in different systems is: head 50.2%, chest 21.8%,
abdomen 23.9% and spine 8.55%. More than 69% of trauma
victims also have orthopaedic injuries, but these are not
usually life threatening.
Determining how these various forces result in patient
injury is complicated. Seek help from the members of the
emergency services who have had the opportunity to
inspect the scene. For example, a frontal impact with a
'bull's-eye' pattern on the windscreen, a collapsed steer-
ing column and indentations on the dashboard indicate
that the driver of this vehicle may have sustained a
number of injuries (Table 2.2).
Following a frontal impact, the patient is at risk of sus-
taining a flexion-distraction type injury to the lumbar
vertebrae if only a lap seat belt has been worn. This can
produce a Chance fracture (vertebral fracture caused by
acute flexion, with horizontal splitting of the spinal pro-
cesses and neural arch), in addition to some or all of the
listed injuries. Motorcyclists, pedestrians and victims
ejected from a car have a significant risk of multiple
injuries, including head, spinal, wrist and lower limb
damage.
A completely different pattern oi injuries results from
rapid deceleration following a fall from a height on to a
solid surface, landing on the feet (Table 2.3).
Knowing the mechanism of injury allows you to predict
possible life-threatening secondary injuries that may not
be immediately apparent (see Ch. 1). It also gives you a
clue as to the degree of energy transfer and, consequently,
the level of tissue damage.
Table 2,2 Potential driver injuries from a frontal
car impact
Facial fractures
Obstructed airway
Cervkal injury
Cardiac contusion
Pneumothorax
Flail chest/fractured ribs
Liver and/or spienk injury
Posterior dislocation of the hip
Acetabular fracture
Fractured femur
Patella fracture
Carpometacarpal injuries
Tarsometatarsal injuries
J
19
2 .
EMERGENCY
Table 2.3 Potential injuries when landing on the
feet from a fall
L
Tarsometatarsal injuries
Calcaneal compression fractures
Ankle fracture
Tibial plateau fractures
Pelvic vertical shear fracture
Vertebral wedge fracture
Cervical injury
Rupture of the thoracic aorta
Tracheobronchial disruption
Liver avulsion
Key point
Anticipate high energy transfer following road
traffic accidents, falls from a height and crush
injuries.
PENETRATING TRAUMA
£-:^&^& ; -^^^^;^^
Around 7% of the annual trauma deaths in the UK are a
result of a penetrating mechanism. The clinical conse-
quences of penetrating trauma are dependent on both
energy transfer and anatomical factors.
Energy transfer
Energy transferred to tissues surrounding the track of a
weapon or missile depend upon:
• The kinetic energy of the weapon or missile (KE = mass /
2 x velocity 2 )
• The mean presenting area of the weapon or missile
• The tendency of the weapon or missile to deform and
fragment
• The density of the tissues
• The mechanical characteristics of the tissues.
It follows that if the missile has a high velocity such as a
rifle bullet, then it carries considerable kinetic energy,
even though its mass is small. Realize that the crucial
speed is the impact velocity, the speed of the missile
when it hits the patient, not its initial velocity as it leaves
the barrel of the gun. In contrast, a knife has a much
lower kinetic energy because it travels at a much slower
speed.
Neighbouring tissues may be injured as kinetic energy
is transferred to them. If the missile impacts in the tissues
and fails to exit, all the kinetic energy is transferred, pro-
ducing the maximum possible damage. This is more
likely if the missile tumbles or fragments within the
tissues. High energy pushes away surrounding tissues
from the missile track, creating a temporary cavity.
Although this lasts but a few milliseconds, it can extend
to 30-40 times the diameter of the missile, depending on
the amount of energy transferred to the tissues and their
elasticity. As the energy waves dissipate, the tissues
rapidly retract to a permanent cavity created by the
destruction of the tissues in the direct path of the missile.
This has three consequences:
1 . There is functional and mechanical disruption of the
neighbouring tissues / related to energy transfer and the
tissue characteristics. Solid organs, such as the liver and
spleen sustain severe damage. Lungs and other low
density organs such as muscle, skin and blood vessels
may escape significant disruption because of their greater
elastic properties.
2. A core of any covering clothing is carried deeply into
the wound by the missile. The higher the projectile vel-
ocity, the finer the shearing of material and the wider its
spread. Negative pressure at the exit wound sucks in
further material, increasing the chance of wound
contamination.
3. If a missile traverses a narrow part of the body the
exit wound is usually larger than the entry wound
because the temporary cavitation effect extends along the
wound track. The temporary cavitation effect finishes if
the missile gives up kinetic energy to become a low
energy missile before leaving the body. There are,
however, no certainties about the size of the entry and exit
wounds.
Anatomical factors
An incision with low energy penetrating trauma, such as
a stab wound, produces a wound with minimum oedema
and inflammation that heals quickly and with minimum
scarring (see Ch. 31). Nevertheless it can still be fatal, for
example from a stab wound to the heart.
BURNS
There are 16 000 NHS admissions with burns each year in
the UK.
Thermal burns are most common, caused by heat from
flames, flashes, scalds and contact with hot surfaces.
Children and the elderly are the most frequent victims,
but scalds are also the most prevalent type of industrial
burn.
Electrical burns cause damage depending on voltage,
duration, tissue resistance and the direction and path
taken by the current (see Ch. 24). Although the entrance
20
TRAUMA
r 2
and exit wounds are treated as thermal wounds, they do
not accurately indicate the extent of the burn. Electric
current travels along the path of least resistance; skin is
resistant and current travels preferentially along arteries,
veins, nerves, bones and tendons, making assessment
difficult.
By\STINJURIES_^
When a bomb is detonated there is a sudden release of
considerable energy. The instantaneous pressure rise in
the surrounding air is the shock front or blast wave,
which travels at supersonic speed through the surround-
ing air in all directions. The pressure falls progressively
as the wave front travels further from the epicentre.
Behind the shock front comes the blast wind, which is
movement of the air itself, rapidly spreading out from the
epicentre, carrying fragments from the bomb or sur-
rounding debris at high velocity, some of it producing
'high energy transfer' wounds.
Primary effect
This is a result of the shock front, mainly affecting air-
containing organs such as lung, bowel and ears. The band
of pressure strikes the surface of the body, causing dis-
tortion and damage depending on its magnitude and rate
of onset. These waves produce most of the damage, at the
air-tissue boundary, associated with 'blast' lung, gut and
tympanic membrane (Table 2.4). If the pulmonary
changes are extensive, a ventilation-perfusion (V/Q)
mismatch develops and hypoxia results. High blast pres-
sures may also lead to air emboli; if they obstruct the cere-
bral or coronary arteries, they may cause sudden death.
area for these fragments is much greater than that of the
shock front. Furthermore, at distances outside this area,
they can still produce considerable damage. The patient
usually presents with multiple, extensive wounds of
varying depth, which are grossly contaminated. As the
distance from the epicentre increases, the wounds become
more superficial.
Tertiary effects
These are the result of the dynamic force of the wind
itself, which can be so great as to carry all or part
of the patient along with it. This results in impact (decel-
eration) injuries and, in extreme cases, amputations.
Miscellaneous effects
These encompass all other causes of injury, including
falling masonry, fires, toxic chemicals, flash burns,
together with acute and chronic psychological disturb-
ances. In addition to the primary effects, blasts give rise
to penetrating, blunt and burn trauma.
MAIN ANATOMICAL SITES OF
TRAUMA
The damage sustained by the patient depends not only on
the biomechanics of the trauma but also on the anatomi-
cal site of injury.
These are discussed in the order in which they are
usually managed clinically.
AIRWAY
Secondary effects
These are the result of the direct impact of fragments
carried in the blast wind. In most explosions, the lethal
Table 2,4 Primary effects of Wast on lungs, gut
and ears
Haemorrhage into alveolar spaces
Damage to alveolar septae
Stripping of bronchial epithelium
Emphysematous blebs produced on the pleural
surface
Contusion of the gut wall
Leakage of blood into the gut lumen
Perforation
Rupture or congestion of the tympanic membrane
The important structures and surface landmarks of the
upper airway are shown in Figure 2.1.
THORAX
Chest wall
1. The upper two ribs are extensively protected by the
scapula and overlying muscle, requiring considerable
force to break them. Consequently if they do break there
is a high risk of concomitant damage to vital structures
such as the thoracic aorta, main bronchi, lungs and spinal
cord. Therefore, closely assess these vital structures if you
discover fractures of the first two ribs. Remember that the
neck is mobile and the pleural cavity and lung apex
project above the clavicle, so pneumothorax or lung
injury may result from penetrating injuries to the lower
21
2 .
EMERGENCY
Soft
palate
Palatine
tonsil
Epiglottis
Hyoid bone
Epiglottic cartilage
Thyroid cartilage
Cricoid cartilage
Pharyngeal recess
Pharyngeal
tonsil
Auditory
tube
Palato-
pharyngeal
fold
Pharyngeal
part of
dorsum of
tongue
Laryngeal
ventricle
i
Fig. 2.1 The upper airway.
neck. Similarly, the lower six ribs overlie the abdominal
cavity when the diaphragm is elevated during expiration,
so both the lung and the upper abdominal viscera may be
injured. Trauma to the 'midzone' of the trunk may be
associated with both abdominal and chest injuries.
Key point
Following stab wounds of the lower chest the
incidence of abdominal visceral involvement is
15%. Following penetrating injury to the lower
chest from gunshots it rises to 46%.
2. When two or more adjacent ribs are fractured in two
or more places they form a flail segment - a flail (proba-
bly from Latin flagellum), classically has a loose segment
hinged on to the handle. The adjacent doubly fractured
clavicle and first rib may also produce a flail segment. On
inspiration/ when the chest wall rises, the partially
detached segment is sucked in - this is paradoxical move-
ment. This may not be visible in the early stages when
spasm of the chest wall muscles splint the fractures but
becomes apparent when the muscles tire. Flail segment
can be life threatening in the presence of underlying
pulmonary contusion, which increases the tendency to
hypoxia as a result of the impaired ventilation.
3. The neurovascular bundle lying in the subcostal
groove may be torn when ribs are fractured. Multiple
fractures or significant disruption may cause massive
haemothorax. The internal mammary artery may be torn.
Large lung lacerations may not stop bleeding when the
lung has been re-expanded by insertion of a chest drain.
4. A one-way valve may develop on the lung surface,
allowing air to enter the pleural cavity during inspiration
but blocking its escape during expiration. This produces
a tension pneumothorax unless the intrapleural pressure
is relieved.
Mediastinum
The trachea, oesophagus and major blood vessels lie
close together, so penetrating injuries of the mediastinum
may damage one or more structures. The surface land-
marks of the mediastinum are medial to the nipple line
anteriorly, or medial to the medial edges of the scapulae
posteriorly.
CIRCUS
1. Tough, inelastic, fibrous pericardium encloses and
protects the heart. Even in a healthy person, a small
collection of blood within the pericardium creates tam-
ponade (French tampion = a plug) occupying space, com-
promising ventricular filling and hence cardiac output.
Intrapericardial haemorrhage usually follows penetrating
trauma of the heart
2. Blunt trauma can cause cardiac contusion, possibly
associated with an overlying sternal fracture. A combina-
tion of vascular spasm, intimal tearing and neighbouring
tissue oedema may lead to coronary artery occlusion.
Myocardial damage may cause dysrhythmias, infarction
and impaired cardiac performance (see below), with
electrocardiographic (ECG) abnormalities. Severe blunt
trauma with rupture of the chordae tendinae produces
mitral or tricuspid valve incompetence.
3. The distal arch of the aorta is anchored just inferior to
the left subclavian artery. During a deceleration injury
there is a risk that the mobile aortic arch will shear off the
fixed descending aorta, disrupting it. The injury may occur
in falls over 9 metres (30 feet) or vehicle crashes at over
50 k.p.h. (30 m.p.h.). In 10% of cases the escaping blood is
contained by the outer, adventitial layer of the aorta but
eventually this is also breached, rapidly exsanguinating
the patient in the absence of surgical intervention.
SKULL
1. The scalp consists of five layers: Skin, subcutaneous
layer, Aponeurosis, Loose areolar tissue, Periosteum
(SCALP). The vascular subcutaneous layer is divided by
22
TRAUMA
2
fibrous bands into loculi, while the areolar layer is loose,
and this is where scalp haematomas collect. If the apo-
neurosis is breached, the wound tends to evert.
2. The interior of the neurocranium is divided into two
levels by a fibrous structure called the tentorium (tent)
cerebelli. The midbrain passes through the opening in the
anterior aspect of this layer, partially covered on its
anterolateral aspects by the corticospinal tract. The ocu-
lomotor (Illrd) nerve leaves the anterior aspect of the mid-
brain to run forward, lying between the free and attached
edges of the tent. In the intact state, there is free com-
munication above and below the tentorium as well as
between the intracranial and spinal subarachnoid spaces.
3. Following head trauma, the development of a mass
lesion above the tent, as from haematoma or cerebral
oedema, may produce a pressure gradient. If this is unre-
lieved it can result in one or both medial surfaces of the
temporal lobes herniating through the opening in the tent.
In so doing, the brain tissue presses on, and damages,
structures in this region, namely the oculomotor nerve
and motor fibres in the corticospinal tract. This is tentorial
herniation, resulting in an ipsilateral (same side) fixed
dilated pupil and contralateral weakness in the limbs. If
the pressure increases further, the medulla and cerebel-
lum are forced downwards into the foramen magnum -
coning. This is a preterminal condition resulting in com-
pression of the vital centres and disturbance of cardio-
vascular and respiratory function.
4. The base of the neurocranium is irregular, with the
sphenoid wings and petrous processes projecting from its
surface. Acceleration and deceleration forces move the
brain over the base of the skull so that it collides with
these projections, which damage it.
5. The internal surface of the neurocranium is lined
with the thick, hard, fibrous dura mater (Latin = hard
mother, a translation from the Arabic) (Fig. 2.2). Its blood
vessels closely adhere to the bone surface, grooving it in
places, so they can be torn when forces are applied to the
overlying bone. A haematoma collects between the bone
and dura - an extradural haematoma; 90% of these are
associated with a fractured skull. The middle meningeal
artery is most at risk and the commonest site is the thin
temporoparietal area.
6. The arachnoid (Greek arachne = spider; like a
spider's web) mater is connected to the pia mater (Latin
translation of Arabic umm raqiqah = thin mother), across
the cerebrospinal fluid (CSF)-filled subarachnoid space,
by thin fibrous strands. Running between these strands
are bridging veins, carrying blood from the brain to the
venous sinuses. With age the brain atrophies, increasing
the subarachnoid and subdural spaces, stretching the
bridging veins and making them more likely to tear fol-
lowing a head injury The resulting blood collects in the
subdural and subarachnoid spaces.
Subarachnoid space
Arachnoid mater
Subdural space
Endocranium
and dura mater
Pia mater
Meningeal
vein and
artery
inner
table of $Z>\
skull
Cerebral vein Cerebral
artery
Grey
matter
White
matter
Fig. 2.2 The meninges and their blood supply.
MAXILLOFACIAL SKELETON
Key point
• The major acute problem associated with
significant facial fractures is the potential for
associated airway obstruction secondary to
swelling, haemorrhage and structural damage.
The maxillofacial skeleton consists of a complex series of
mainly aerated bones which provide a firm but light
foundation to the face (Fig. 2.3). The nasal, frontal and
zygoma tic-maxillary buttresses provide vertical support,
with lateral stability coming from the zygomatic-
temporal buttresses. Several of these bones, especially
those making up the bony orbits, are closely associated
with nerves and blood vessels, which may therefore be
damaged when these bones are broken. In addition, the
associated bleeding and deformity can lead to obstruction
of the patient's airway.
Nasoethmoidal-orbital fractures
These result from trauma to the bridge of the nose or
medial orbital wall. In view of their location, they are asso-
ciated with lacrimal duct (Latin lacrima, Greek dakre = tear)
injury, dural rupture and traumatic telecanthus (Greek
tele = far + kanthos - angle at junction of the eyelids);
the medial canthus is tethered to the displaced medial
orbital wall, drawing it down and widening the angle.
23
2 -"
EMERGENCY
Frontal bone
Nasal bone
Sphenoid bone
Ethmoid bone
Lacrimal bone
Zygomatic bone
Maxillary bone
Mandible
Fig. 2.3 The facial skeleton.
Blow-out fractures
These result from blunt injury to the eyeball, increasing
intraorbital pressure, depressing and fracturing the thin
floor of the orbit, often with associated fracture of the
medial orbital wall. The infraorbital nerve is usually
damaged, producing anaesthesia of the cheek, upper lip
and upper gum and also diplopia (Greek diploos = double
+ ops = eye; double vision), especially to upward gaze.
This results from a combination of muscle haematoma,
third nerve damage, entrapment of periorbital fat and,
in a minority of cases, true entrapment of extraocular
muscles. Subcutaneous emphysema (Greek em = in +
physaein = to blow; to inflate) occurs if the fracture extends
into a sinus or nasal antrum.
Zygomatic complex fractures
Two types can be caused by blunt trauma. Zygomatic arch
fractures are produced by a direct blow and can give rise to
limited mouth opening due to impingement of temporalis
muscle. The more serious 'tripod 7 type of fracture involves
the displacement of the whole zygoma. This bone can be
compared to a four-legged stool, with the 'legs' being the
floor and lateral wall of the orbit, the zygomatic arch and
the lateral wall of the antrum. The 'seat' of the stool cannot
be moved without displacement of at least two of the legs'.
This is associated with lateral subconjunctival haemorrhage
and infraorbital anaesthesia. In addition, the displacement
leads to a downward angulation of the lateral canthus and
either trismus or an open bite.
Fractures of the middle third of the facial
skeleton
It takes approximately 100 times the force of gravity to
break the middle third of the face. Consequently, patients
with this condition have significant multisystem trauma
in addition to the malocclusion, facial anaesthesia and
visual symptoms described above. Traditionally, the
fractures are classified using the system devised by the
French paediatric orthopaedic surgeon, Rene Le Fort in
1901 (Fig. 2.4). The grade of fracture is often asymmetri-
cal, that is, different on two sides. The Le Fort I fracture
runs in a transverse plane above the alveolar ridge to the
pterygoid region. Le Fort II extends from the nasal bones
into the medial orbital wall and crosses the infraorbital
rim. Le Fort III detaches the middle third of the facial
skeleton from the cranial base; it is therefore commonly
associated with fractures of the base of the skull and
bloody CSF rhinorrhoea and otorrhoea (Greek rhinos =
nose, otos = ear + rhoia = a flow). A characteristic 'dish
face' may be evident due to retropositioning (Greek
retros - backward) of the midface along the base of the
skull
Mandibular fractures
The mandible, like the pelvis, is a ring structure and
therefore rarely fractured in isolation. Usually there are
multiple fractures or an injury to the temporomandi-
bular joint. Common fracture sites are the condylar
process, through the posterior alveolar margin, and
Fig. 2.4 Common sites of fracture of the midface.
24
TRAUMA
2
Fig. 2.5 Common sites of fracture of the mandible.
through the alveolar margin anterior to the premolar
teeth. In the majority of the latter cases the fracture is
open as it extends between the teeth and communicates
with the oral cavity (Fig. 2.5). It is common to find
numbness of the lower lip on the affected side and
malocclusion.
ABDOMEN AND GENITOURINARY
SYSTEM
SSfH^SS^&^^i*W&*~
&*& ■>?-- ^-tV^if -F^^^^^^^i^r
Peritoneal cavity
This can be subdivided into intrathoracic and abdominal
regions. Remember, however, that on expiration, the
diaphragm rises anteriorly to the level of the fourth inter-
costal space. As a result, several of the intraperitoneal
organs, such as the liver, spleen and stomach, lie within
the bony thorax and are therefore at risk if the patient
suffers trauma to the lower chest.
1. Diaphragmatic injury is uncommon and rarely
occurs in isolation. It may result from both blunt and
penetrating injury. The former tends to occur with greater
force than the latter and commonly leads to larger tears
in the diaphragm, through which abdominal contents
may enter the thorax and compromise respiration.
Injuries to the diaphragm may be so slight that the patient
is asymptomatic and the damage may not be discovered
until weeks, months or even years later.
2. The liver and biliary tree are largely covered by the
rib cage, affording some protection from injury. Although
numerically less common than splenic injury, liver
injuries account for more deaths as a result of unsus-
pected intra-abdominal haemorrhage. Consider the
possibility of underlying liver damage when assessing
trauma victims.
Because of their location, the gallbladder and extra-
hepatic biliary tract are usually damaged in association
with other viscera. Liver trauma is the most common
coexisting pathology (50% of cases), but there is a signif-
icant chance of pancreatic damage (17% of cases).
Consequently, injury of the gallbladder and biliary tree
are usually masked by the features resulting from damage
to the surrounding viscera. This condition has an overall
mortality of 16% due to coexisting organ injuries. Blunt
trauma is the usual cause of gallbladder damage, and
rupture is more likely when the gallbladder is distended,
as between meals.
3. The spleen is the most commonly injured solid organ
in the abdomen following blunt trauma, and is therefore
a frequent cause of shock in patients with abdominal
injury. Any injury to the left lower chest or upper
abdomen may cause splenic damage, ranging from small
tears to complete shattering of the organ.
4. Stomach injury is infrequent following blunt trauma
but the stomach may be punctured by penetrating
wounds; this usually presents as peritonitis.
5. Small bowel damage may result from blunt or pen-
etrating wounds, as well as blast injury. Blunt trauma and
blast can cause bowel injury in one of three ways: (1) the
force may squeeze the viscus between the anterior
abdominal wall and vertebral column; (2) the bowel may
rupture as a result of a sudden increase in pressure within
the lumen, as when the abdomen is compressed (the
closed-loop phenomenon); (3) the bowel may be rendered
ischaemic by damage to the mesentery and its vessels.
Mesenteric tears often result if the abdomen is subjected
to deceleration or shearing forces; it is particularly
common at points where the bowel crosses the interface
between the intra- and retro peritoneum, including the
duodenojejunal flexure and ileocaecal junction. Blast
injuries can also lead to multiple intestinal perforations
and areas of infarction. Bowel penetration injury usually
produces small tears in the wall but may completely tran-
sect it. Unlike injuries to the liver and spleen, trauma to
the bowel is rarely immediately life threatening. As with
the stomach, the major problem is peritonitis, which
develops over several hours as a result of leakage of
bowel contents into the peritoneum.
Retroperitoneum
1 . Injuries to the retroperitoneal organs are more diffi-
cult to diagnose than are those in the peritoneal cavity
because they are less accessible to physical examination
and investigation.
2. Pancreas and duodenum may be injured as a result
of both blunt and penetrating trauma, the commonest
25
2
EMERGENCY
mechanism being that of the unrestrained car driver
impacting with the steering wheel.
3. Bowel. All of the caecum and ascending colon, as
well as between one- and two-thirds of the circumference
of the descending colon He within the retroperitoneal
space. The remainder of the colon is located within the
peritoneal cavity. Blunt or penetrating trauma can
damage any part of the colon, allowing leakage of the
bowel contents. However, in cases of retroperitoneal per-
foration, the symptoms are usually ill-defined and slow to
develop / leading to delayed diagnosis and increasing the
risk of abscess formation.
4. Vascular. The abdominal aorta is susceptible to
damage as a result of penetrating injury. Severe trauma
is almost invariably lethal, but lesser injuries manifest
as hypotension and /or symptoms of ischaemia. If the
haemorrhage is contained within the retroperitoneum,
the hypotension may be transient, responding to fluid
resuscitation. Later, a retroperitoneal haematoma may
become visible as bruising in the flank or back,
described by the Newcastle surgeon George Grey Turner
in 1920, or around the umbilicus, described in 1919
by Thomas Cullen, gynaecologist of Johns Hopkins
Hospital in Baltimore. The inferior vena cava is suscep-
tible to the same types of injury as the aorta, resulting in
significant blood loss, although usually less than from
an equivalent injury to the aorta. This is because the
intravenous pressure is low and the external tissue pres-
sure is relatively higher. However, if this pressure is lost,
as occurs in the presence of a large wound, external pres-
sure is diminished, so haemorrhage increases and may
be life threatening.
5. Renal system. The kidneys are well protected by soft
tissue in front and bone and muscle behind. As a result,
isolated injury to the kidneys is uncommon, barring
sporting incidents. Significant renal damage following
major penetrating or blunt trauma is usually associated
with multiple organ injuries. Ureteric injury of either type
is uncommon. Assiduously investigate macroscopic
haematuria, or microscopic haematuria in the presence of
shock.
Pelvis
1. Pelvic injuries mainly involve the bladder and
posterior urethra.
2. Urinary system. Although the bladder lies within the
pelvis, when full it may extend as high as the umbilicus
and be susceptible to injury to the lower abdomen.
Compression of the abdomen increases intravesical pres-
sure and may cause 'full-bladder blowout', although
more commonly the bladder is punctured by bone
fragments generated by fracture of the pelvis. Bladder
rupture into the peritoneal cavity produces peritonitis.
Extraperitoneal rupture is usually less dramatic but, if it
remains undiagnosed, tissue necrosis follows. The short,
female urethra is rarely injured. In males, posterior ure-
thral injury usually occurs above the urogenital
diaphragm (which contains the external sphincter ure-
thrae) as a result of pelvic fracture and is therefore often
associated with injuries to other body regions. Anterior
urethral injury is generally the result of blunt trauma to
the perineum, such as falling astride a beam, and is there-
fore usually an isolated injury. If urethral rupture is com-
plete, the patient is unable to pass urine. In contrast, a
lesser injury, such as a submucosal haematoma, makes
micturition slow, painful, but possible.
3. The pelvis contains the rectum and the female repro-
ductive organs. In addition to perforation from bony
pelvic fragments following trauma, injuries to the rectum
are similar to those described for the colon and bowel
above. Uterine injuries are uncommon but can result
from both blunt and penetrating trauma. The chance of
damage from either mechanism is increased during
pregnancy because of the greater uterine size.
Abdominal wall
1. In fit, athletic individuals this forms a firm muscular
layer, offering considerable protection from blunt trauma.
Protection is reduced in children and those with poorly
developed muscles. The anterior abdominal muscles can
rupture spontaneously, for example following vigorous
exercise or coughing. The most common cause of tears is
compression from a seat belt in a deceleration injury; if it
produces an imprint of the overlying clothes and seat belt
on the skin, there is a high probability of significant intra-
abdominal injury.
2. Although penetrating trauma can breach the ante-
rior abdominal wall, it may not necessarily cause intra-
abdominal injury. The degree of damage sustained
depends on the nature of the weapon used: the wound
may be either a stab wound or gunshot wound.
Perineum
Blunt or penetrating injury may injure the penis.
Fractured penis infrequently results from forceful
bending of the erect organ, rupturing one or both corpora
cavernosa, causing a large subcutaneous haematoma and
detumescence (Latin de = reversal + temure = to swell).
The testes can be damaged by blunt or, more rarely,
penetrating trauma. Rupture of the testis following the
former is uncommon because of the scrotal position,
cremasteric retraction and the frictionless surface of the
tunica vaginalis. All these features allow the testis to
evade the direct effects of blunt trauma.
26
TRAUMA
r 2
BONY PELVIS
The bony pelvis is usually injured as a result of road
traffic accidents (60-80%) or falls from a height (10%).
These mechanisms give rise to anteroposterior compres-
sion, lateral compression or vertical shear acting on the
pelvis either singularly or in combination. They are all
capable of producing pelvic instability and haemorrhage
from the vascular and bony damage. Because of the
nature of this high energy transfer, 98% of patients with
major pelvic trauma have other injuries (Table 2.5). The
mortality rate is therefore high, at 10%, but rises to 30%
with an open fracture, and in this case mortality
approaches 100% if the open fracture is missed.
The bones of the pelvis can be separated only if the liga-
ments uniting them are torn. When this occurs, structures
running close to the ligaments, such as vessels and
nerves, can be damaged. The resulting bleeding is usually
venous and extraperitoneal, so it can be life threatening.
However, a tamponading (plugging) effect can be
achieved if fractures occur while the ligaments remain
intact, in which case haemorrhage is less severe, and
mortality lower.
Table 2.5 Associations with pelvic
fractures
Major haemorrhage
over 70%
Musculoskeletal injury
over 80%
Intraabdominal injury
18-35%
Urologkal injury
12-20%
Lumbosacral plexus injury
8-30%
LIMBS
Bone
The size, shape and consistency of bone varies with age.
Old bones require less force to break them than young
ones because they are more brittle and often osteoporotic
(Greek poros - passage; porous or rarefaction). In chil-
dren, fractures may involve the physis (Greek = nature;
growth plate), resulting in deformity if reduction is not
accurate.
Bone is a living tissue with a generous blood supply
and can bleed profusely after injury. Furthermore, blood
loss from adjacent vessels and oedema into the sur-
rounding tissues can be severe enough to cause hypo-
volemic shock. The approximate blood loss with some
closed fractures is: pelvis 1.0-5.0 litres, femur 1.0-2.5
litres, tibia 0.5-1.5 litres and humerus 0.5-1.5 litres. These
volumes can be much higher if there is an open fracture
(see below).
Nerves
These tend to lie within neurovascular fascial bundles
close to the long bones in the limbs. This close proxim-
ity is particularly noticeable around joints, making
the nerves prone to damage following fractures and
dislocations.
Structure and function of a peripheral nerve
The neuronal processes making up a nerve trunk are
grouped into fascicles (Latin fascis - bundle). In the more
proximal segments there is considerable crossing over
and rearrangement between fascicles, but, more distally,
below the elbow for example, the fascicular arrangement
is constant, predictable and corresponds to the eventual
motor and cutaneous branches. Some nerves, such as the
ulnar, have small numbers of well-defined fascicles;
others, such as the median nerve, have large numbers of
smaller ones.
You need to know the connective tissue framework of
the nerve in order to understand nerve injuries. The out-
ermost layer is the epineurium (Greek epi = upon + neuron
= nerve), the chief characteristic of which is mechanical
strength. It is usually in a state of longitudinal tension,
which is why the ends of a cut nerve spring apart. Each
fascicle is surrounded by perineurium (Greek peri =
around); this functions as a blood-nerve barrier and
determines the biochemical environment of the nerve
tissue. The individual axons are invested in endoneurium
(Greek endo - within), which forms conduits guiding each
axon to the appropriate end organ.
The nerve is nourished by an internal longitudinal
plexus of vessels, fed at intervals by perforators from the
adventitia. This plexus becomes occluded if the nerve is
subjected to undue tension, otherwise it can support the
nerve trunk even when it has been lifted from its bed over
a distance. The cell body and axonal parts of the neuron
communicate with each other chemically by means of the
axoplasmic transport system. Under normal conditions
this carries transmitter substances centrifugally (Latin
centrum + fugare = to flee); during regeneration after
injury, structural proteins are also carried. Signalling
molecules from the end organs or from axons which are
damaged are conveyed to the centrally sited cell body,
thus transmitting peripheral influences proximally to the
nucleus, which controls the repair.
Vessels
Following trauma, the intimal layer may be the only part
of a limb artery damaged. This can be very difficult to
detect clinically, initially because distal pulses and capil-
lary refill are maintained. Subsequently, the intimal tear
27
EMERGENCY
can become a focus for the formation of an intravascular
thrombosis and can also give rise to distal embolization.
More overt acute signs are seen only if a significant area
of the lumen is occluded. When all the layers of the artery
are transected transversely, the vessel goes into spasm
from constriction of the muscle fibres in the media, limit-
ing the degree of blood loss. Conversely, if there is a
partial or longitudinal laceration, the muscle spasm tends
to keep the hole in the artery open, and blood loss
continues.
Veins have less muscle in their walls but the venous
pressure is lower than arterial pressure. However, many
veins have external attachments, especially in the pelvis
and intracranial sinuses, which hold them open. In addi-
tion, many venous tears produce side holes rather than
transections, prejudicing the sealing effects of annular
contraction. Consequently, blood continues to leak from
the lumen until direct pressure is applied.
Limb compartments
These are regions in the limbs where skeletal muscle is
enclosed by relatively non-compliant fascia. Running
through these areas are blood vessels and nerves, the
function of which can be affected if intracompartmental
pressure rises above capillary pressure. This is most com-
monly seen in the four compartments around the tibia
and fibula. Nevertheless, compartments also occur in the
shoulder, forearm, hand, buttocks and thigh, and these
can also give rise to the compartment syndrome (see
below).
SPINAL COLUMN
y^S^^W^^fe^.^^
AW^ i &ViW: r ^T%&flfcy?4*.?&teS
The stability of the vertebral column depends mainly on
the integrity of a series of ligaments but the vertebral
bodies and the intervertebral discs also contribute. These
can be considered as three vertical columns. The anterior
column comprises the anterior longitudinal ligament and
the anterior half of both the vertebral body and inter-
vertebral disc. The middle complex consists of the poste-
rior longitudinal ligament and the posterior half of both
the vertebral body and intervertebral disc. The posterior
column comprises the remaining posterior ligament
complex and the facet joints; it is structurally the most
important column. If any two of these columns are dis-
rupted, the vertebral column becomes unstable.
The spinal cord runs down the spinal canal to the level
of the second (adult) or third (baby) lumbar vertebra. The
size of the space around the cord in the canal varies,
depending on the relative diameters of the spinal cord
and spinal canal. In the region of the thorax it is very
small because the spinal cord is relatively wide. In
contrast, there is a large potential space at the level of C2.
Consequently, injuries in this area are not automatically
fatal because there is a potential space behind the odon-
toid process or dens (Latin - tooth).
Key point
• Steel's rule of three states that at the level of
the first cervical vertebra one-third of the
available space in the vertebral canal is
occupied by the odontoid process and
one-third by the spinal cord, leaving a free
space of one-third.
Free space in the spinal canal is an important safety factor
in adaptation to injury; it can be reduced by spinal steno-
sis or posterior osteophytes.
Incidents leading to spinal injury are:
• Road traffic accidents
48%
• Falls
21%
• Violent acts
14%
• Sport
14%
• Others
3%
1. Road traffic accidents can result from side, rear or
front collision. Ejection from a car increases the chance of
a spinal injury to approximately 1 in 14. Rear-end colli-
sions can produce hyperextension of the neck followed by
hyperflexion (the 'whiplash phenomenon'). Unprotected
victims, such as pedestrians hit by cars or motorcyclists,
have a higher chance of sustaining a spinal injury than
those within a vehicle.
2. Rugby football, especially following collapse of the
scrum, is infamous for producing spinal trauma, but
almost all sports have been implicated in spinal injury.
Diving into shallow water, particularly by young males
following alcohol imbibition, is a common cause of neck
injuries during the spring and summer months. The
victim usually misjudges the depth of the water or dives
from too steep an angle, hitting his head on the underly-
ing solid surface. Because of the mechanism of injury, 50%
of patients with spinal trauma have other injuries, 7-20%
have head injuries, 15-20% have chest injuries and
around 2.5% have abdominal injuries.
3. Injury may result from single or combined forces,
including flexion, extension, rotation, lateral flexion,
compression and distraction. In the adult, the vertebral
column is more likely to be injured at C5/C6/C7 and
T12/L1. The more mobile cervical and lumbar regions
meet the relatively immobile thoracic segments, focusing
stress and increasing the chance of fracture at these
points.
28
TRAUMA
2
SKIN
The principal soft tissue in the body is the skin. Ageing
decreases the amount of collagen in both the skin and
subcutaneous tissues, as well as weakening the elastic
fibres. This process can be accelerated by the administra-
tion of long-term steroids. These changes reduce the
tensile strength of skin, allowing extensive lacerations to
develop with minor trauma.
THE BODY'S RESPONSE TO TRAUMA
Injury initiates many well-developed physiological
responses. Consequently, when you treat trauma victims
you are presented with a complex combination of patho-
physiological changes, some of which are a direct result
of the injury and others the body's response to the initial
insult. The underlying mechanisms controlling response
are a mixture of cardiovascular, paracrine and endocrine
reactions. Individual examples of the more important
pathophysiological processes are listed in Table 2.6.
METABOLIC RESPONSE TO INJURY
Table 2.6 Pathophysiological effects contributing
to the body's response to trauma
Metabolic response to injury
Shock and cardiovascular pathophysiology
Systemic inflammatory response syndrome (SIRS)
Coagulopathy
Multiorgan failure {MQFJ
Neu ^pathophysiology
Spinal injuries
Fractures
Peripheral nerve injury
Compartment syndrome
Crush syndrome
Fat emboli
Wound healing
Burns
Three phases are recognized: the early, acute ebb phase, fol-
lowed by the flow phase if resuscitation and homeostasis
are successful, or by necrobiosis if treatment fails and death
ensues (Fig. 2.6). Following very severe injuries, the ebb
phase may be short and necrobiosis may already have
started by the time the patient reaches the accident and
emergency (A & E) department
Ebb phase
1. The body anticipates danger and prepares for fight
or flight (the defence reaction). Superimposed on this is
• Changes in homoeostatic
reflex activity (thermoregulato-
ry and cardiovascular)
■ Compensation of fluid loss
• Increase in plasma hormone
levels (e.g. catecholamines)
• Mobilization of energy reserves
• Changes in fuel utilization
• Initiation of acute phase
plasma protein response
■ Increase in metabolic rate
Insulin resistance
Increase in skeletal muscle breakdown
— loss of lean body mass
Increase in urinary nitrogen loss
r
APPRECIATION
OF DANGER
ACUTE (EBB) RESPONSE
(12/24 HR)
DELAYED (FLOW) RESPONSE
(WEEKS)
RECOVERY
INJURY
NECROBIOSIS — DEATH
Fluid loss
Tissue damage
* Failure of tissue O2 delivery
* Anaerobic metabolism
* Organ failure
Fig. 2.6 Defence reaction.
29
EMERGENCY
the body's response to haemorrhage, tissue injury, pain
and hypoxia 7 the response being related to the severity of
the injury. The ebb phase is characterized by mobilization
of energy reserves and changes in cardiovascular reflex
activity. The latter corresponds to the clinical state
commonly referred to as 'shock' (see below). Increased
sympathetic nervous activity links these changes and is
reflected by rises in plasma catecholamine (derived from
catechu an extract of Indian plants), such as adrenaline
(epinephrine) and noradrenaline (norepinephrine)/ with
concentrations proportionate to the severity of the injury.
Additionally there is a rapid secretion of hormones from
the posterior and anterior pituitary gland as well as the
adrenal medulla.
2. Increased sympathetic activity stimulates the break-
down of liver and muscle glycogen, leading to increased
levels of plasma glucose. This hyperglycaemia is potenti-
ated by reduced glucose utilization in skeletal muscle
because high adrenaline (epinephrine) levels inhibit
insulin secretion. A relative intracellular insulin resistance
develops, the mechanism of which is unclear, although
glucocorticoids maybe involved.
3. The changes in carbohydrate metabolism in the ebb
phase can be interpreted as defensive. In addition to pro-
viding fuel for fight or flight, hyperglycaemia may also
play a role in compensating for post-traumatic fluid loss,
both by mobilizing water associated with glycogen and
through its osmotic effects. The decrease in glucose clear-
ance associated with the development of insulin resist-
ance can be considered as a mechanism for preventing the
wasteful use of the mobilized carbohydrate, which is an
essential fuel for the brain and the wound, at a time when
the supply of nutrients may be limited.
4. Increased sympathetic activity also mobilizes fat
from adipose tissue. Plasma concentrations of non-
esterified fatty acids (NEFAs) and glycerol are raised fol-
lowing accidental injury in humans, although the rela-
tionship with injury severity is complex. Plasma NEFA is
lower after severe injuries than after moderate ones, poss-
ibly resulting from metabolic effects such as stimulation
of re-esterification within adipose tissue by raised plasma
lactate levels, or circulatory factors such as poor perfusion
of adipose tissue.
5. Increased plasma Cortisol, mediated by adrenocorti-
cotrophic hormone (ACTH), occurs rapidly following all
forms of injury, although the relationship with severity is
again complex. Unexpectedly low Cortisol concentrations
are found following severe injuries, which cannot be
related to a failure of the ACTH response but are possibly
caused by impaired adrenocortical blood flow in major
trauma.
6. In normal subjects the total consumption of oxygen
per minute (Vo 2 ) is constant throughout a wide range of
oxygen delivery (Do 2 X The normal Vo 2 for a resting male
is 100-160 ml min -1 m~ 2 and the normal value of Do 2 in
the same person is 500-720 ml min' 1 m" 2 ; therefore/ tissues
are taking up only 20-25% of the oxygen brought to them.
This is known as the oxygen extraction ratio (OER) and
demonstrates that normally there is great potential for
the tissues of the body to remove more oxygen from the
circulating blood.
7. Following trauma, both oxygen delivery and con-
sumption can be affected. In simple haemorrhage, Vo 2 is
maintained in the face of falling Do 2 by increasing the
oxygen extraction ratio. When tissue injury occurs on the
background of haemorrhage, despite the oxygen extraction
ratio rising, oxygen consumption falls with oxygen deliv-
ery. In other words, Vo 2 has become supply dependent.
8. Nociceptive (Latin nocere — to hurt + recepere = to
receive) stimulation also complicates the cardiovascular
response to fluid loss. The heart rate response to simple
haemorrhage is an initial tachycardia, mediated by the
baroreflex (Greek baros — weight, pressure)/ followed, as
the severity of haemorrhage increases, by a bradycardia
(Greek bradys = slow) mediated by the 'depressor reflex'.
The sensitivity of the baroreflex is reduced by injury,
contrary to the increase seen following haemorrhage.
Impairment of the baroreflex, which can persist for
several weeks following modest injuries, means that
vasopressors such as vasopressin (antidiuretic hormone,
ADH) released acutely after injury are more effective in
maintaining blood pressure than normally, when the
baroreflex buffers their pressor effects. The bradycardia
caused by the depressor reflex is also markedly
attenuated by additional tissue injury. This complex
interaction between the cardiovascular responses to
haemorrhage and injury may be harmful. Maintenance of
blood pressure following haemorrhage and injury can be
achieved at the expense of intense vasoconstriction in
peripheral vascular beds. Reduced gut blood flow is
thought to be pivotal in the production of inflammatory
cytokines such as interleukin 6 (IL-6) and tumour
necrosis factor a (TNFa). Raised levels of these inflam-
matory markers/ as well as abnormalities in IL-10, an
anti-inflammatory cytokine, may lead to further tissue
damage and increase the likelihood of developing
multiple organ failure.
9. There is clinical evidence for changes in the control
of thermoregulation: severely injured patients do not
shiver, despite having body temperatures below the
normal threshold for the onset of shivering. The selection
of the ambient temperature for thermal comfort is modi-
fied. This may be centrally mediated, but cytokines are
likely to be important.
10. If tissue damage and fluid loss from the circulation
are so severe that endogenous homoeostatic mechanisms
are overwhelmed and resuscitation is inadequate, the
necrobiotic phase begins. This is characterized by a
30
TRAUMA
2
progressive imbalance between oxygen demand and
supply in the tissues, leading to a downward spiral of
anaerobic metabolism, with irreversible tissue damage
and death.
Key point
• If the ebb phase is successfully managed and
oxygen delivery maintained, the flow phase
ensues.
Flow phase
1 . The main features are increased metabolic rate and
urinary nitrogen excretion associated with weight loss
and muscle wasting, reaching a maximum at 7-10 days
following uncomplicated injuries. This response pattern
may last many weeks if sepsis and /or multiple organ
failure supervene. The increased metabolic rate, which is
proportional to the severity of injury, results from neural,
hormonal and immunological factors. The wound acts
as the "afferent arc', priming the inflammatory response,
while systemically released stress hormones perpetuate
the metabolic changes (efferent arc). The complex inter-
action between the factors is still unclear.
2. The wound, whether a fracture site or a burned
surface, can be considered as an extra organ that is
metabolically active and has a circulation that is not under
neural control. It consumes large amounts of glucose,
which is converted to lactate, which in turn is carried to the
liver and reconverted to glucose. This is an energy-
consuming process, reflected by an increase in hepatic
oxygen consumption. Other factors possibly contributing to
the hypermetabolism are: increases in cardiac output
(needed to sustain a hyperdynamic circulation); the energy
cost of the latent heat of evaporation of water from, for
example, the surface of the burn; the energy costs of sub-
strate cycling (metabolic processes which involve the
expenditure of energy without any change in the amount of
either substrate or product); and increased protein turnover.
3. During the flow phase, the metabolic rate seldom
exceeds 3000-4000 kcal per day, twice the normal resting
metabolic expenditure, with the highest values following
major burns. Energy expenditure is often lower than
expected and may be close to, or even lower than, values
predicted from standard tables. This is because the hyper-
metabolic stimulus of injury or sepsis is superimposed on
a background of inadequate calorie intake, immobility
and loss of muscle mass, all of which tend to reduce
metabolic rate.
4. Hypermetabolism of the flow phase is fuelled by
increases in the rates of turnover of both fat and glucose.
Turnover of NEFAs is raised in relation to their plasma
concentration, and the normal suppression of fat oxida-
tion following the administration of exogenous glucose is
not seen in these hypermetabolic patients. Both changes
have been attributed to increased sympathetic activity,
although plasma catecholamine concentrations are not
always increased at this time. The rate of hepatic gluco-
neogenesis is increased from a number of precursors,
such as lactate and pyruvate from the wound and muscle,
amino acids from muscle protein breakdown, and glyc-
erol from fat mobilization. This increase in hepatic
glucose production is not suppressed by infusing large
quantities of glucose into burned or septic patients. The
apparent resistance to the effects of insulin is mirrored by
the failure of peripheral glucose utilization to rise to the
extent predicted from the raised plasma glucose and
insulin concentrations. This insulin resistance in, for
example, uninjured skeletal muscle, seems to be an intra-
cellular, postreceptor change.
5. The balance between whole body protein synthesis
and breakdown is obviously disturbed in the flow phase.
The observed changes probably represent the interaction
between the severity of injury and the nutritional state:
increasing severity of injury causes increasing rates of
both synthesis and breakdown, while undernutrition
depresses synthesis. Thus, increasing nutritional intake
should move a patient towards nitrogen balance but,
despite technical advances for administering nutrients
and modifications to the type and composition of feeding
regimens, no amount of nitrogen is sufficient to produce
a positive balance following severe injuries. Nevertheless,
the use of anabolic agents, such as growth hormone or
testosterone derivatives, and manipulations of ambient
temperature may be advantageous as the patient moves
from the catabolic flow phase into the anabolic convales-
cent phase.
6. A major site of net protein loss is skeletal muscle,
both in the injured area and at a distance. For example,
following moderate injury the patient can lose 2 kg of lean
body mass, sufficient to compromise mobility, especially
in the elderly whose reserves of muscle mass and strength
are already reduced. Although the changes in skeletal
muscle are very obvious, the liver is another tissue in
which changes in protein synthesis are of particular inter-
est after injury; it is the source of the acute-phase reactants
such as C-reactive protein, fibrinogen and a r antitrypsin,
the concentrations of which rise in response to infection,
inflammation and trauma.
7. These metabolic changes, not attributable to starva-
tion or immobility, can be mimicked to some extent by the
infusion of the counterregulatory hormones glucagon,
adrenaline (epinephrine) and Cortisol. However, the
plasma concentrations required to elicit relatively modest
increases in nitrogen excretion, metabolic rate and induce
31
2
EMERGENCY
peripheral insulin resistance are much higher than those
found in the flow phase, although they are similar to
those noted in the ebb phase.
SHOCK AND CARDIOVASCULAR
PATHOPHYSIOLOGY
Shock can be defined as inadequate organ perfusion and
tissue oxygenation. Tissue oxidation depends on ade-
quate pulmonary function with satisfactory gas exchange,
together with an adequate quantity of functioning
haemoglobin able to deliver and release oxygen to the
tissues.
When a sufficient cell mass has been damaged, shock
becomes irreversible and the patient inevitably dies.
Fortunately, the body has several compensatory mech-
anisms which sustain adequate organ perfusion and
lower the risk.
Circulatory control
Pressure receptors in the heart and baroreceptors in the
carotid sinus and aortic arch trigger a reflex sympathetic
response via control centres in the brainstem in response to
hypovolaemia. The sympathetic discharge stimulates many
tissues in the body, including the adrenal medulla, which
releases increased amounts of systemic catecholamines, so
enhancing the effects of direct sympathetic discharge, par-
ticularly on the heart. This prevents or limits the fall in
cardiac output by positive inotropic (Greek inos = muscle,
fibre + tvepeein - to turn, influence) and chronotropic (Greek
chronos = time + trepeein; influencing time or rate) effects on
the heart and by increasing venous return as a result of
venoconstriction. Furthermore, selective arteriolar and pre-
capillary sphincter constriction supplying non-essential
organs, such as skin and gut, maintains perfusion of vital
organs, such as brain and heart. Selective perfusion lowers
hydrostatic pressure in capillaries serving non-essential
organs, also reducing diffusion of fluid across the capillary
membrane into the interstitial space, thereby decreasing
further loss of intravascular volume. Reduction in renal
blood flow is detected by the juxtaglomerular apparatus in
the kidney, which releases renin. This leads to the formation
of angiotensin II and aldosterone; these, together with ADH
released by the pituitary gland, increase renal reabsorption
of sodium and water, reducing urine volume, and helping
to maintain the circulating volume. Renin, angiotensin II
and ADH can also produce generalized vasoconstriction,
promoting increase in venous return. In addition, the body
attempts to enhance the circulating volume by releasing
osmotically active substances from the liver, which increase
plasma osmotic pressure, drawing interstitial fluid into the
intravascular space.
Oxygen delivery
Although sympathetically induced tachypnoea (Greek
tachys = rapid + pnoia = breathing) occurs, it does not
increase oxygen uptake because the blood haemoglobin
traversing ventilated alveoli is already fully saturated.
Causes of shock
1. Reduced venous return following haemorrhage is
the commonest cause of shock in traumatized patients.
Bleeding may be occult, collecting in the large spaces of
the thorax, abdomen and pelvis. As well as the potential
spaces intrapleurally and within the retroperitoneum,
blood may be lost into muscles and tissues around long-
bone fractures; in addition, intravascular volume may be
reduced as a result of leakage of plasma into the intersti-
tial spaces. This can account for up to 25% of the volume
of tissue swelling following blunt trauma. The rate of
blood returning to the heart depends on the pressure
gradient created by the high hydrostatic pressure in the
peripheral veins and low hydrostatic pressure in the
cardiac right atrium. Any reduction in this gradient, as
from tension pneumothorax, cardiac tamponade or
increasing right atrial pressure, reduces venous return to
the heart. External compression on the thorax or abdomen
can have a similar action in obstructing the venous return.
2. Cardiogenic shock from ischaemic heart disease
and cardiac contusions have negative inotropic effects.
Nevertheless, it does not occur unless more than 40% of
the left ventricular myocardium is dead or severely
damaged. In cardiogenic shock the compensatory sym-
pathetic and catecholamine responses only serve to
increase the myocardial oxygen demand and further
increase ischaemia. Certain dysrhythmias alone, from
pre-existing cardiac ischaemia or following cardiac
contusion, significantly reduce cardiac performance. Be
aware that all antiarrhythmic agents may have negative
inotropic effects, impeding the patient's physiological
response to the injury. Cardiac tamponade not only preju-
dices venous return but also restricts ventricular filling.
3. Reduced arterial tone complicates spinal injury
above T6 by impairing sympathetic nervous system
outflow from the spinal cord below that level.
Consequently, both the reflex tachycardia and vasocon-
striction responses to hypovolaemia are restricted to a
degree proportional to the level of sympathetic block.
Generalized vasodilatation, bradycardia and loss of tem-
perature control can follow high level spinal injuries, pro-
ducing neurogenic shock; additional nervous damage may
result from the reduced blood supply to the spinal
column. Any associated haemorrhage from the injury
aggravates this situation, further reducing spinal blood
flow. In addition, these patients are very sensitive to any
32
TRAUMA
2
vagal stimulation. For example, pharyngeal suction can
aggravate the bradycardia, leading to cardiac arrest.
4, Septic shock results when circulating endotoxins,
commonly from Gram-negative organisms/ produce
vasodilatation and impair energy utilization at a cellular
level. Hypoxia can devlop even with normal or high
oxygen delivery rates, because the tissue oxygen demand
is extremely high and there is impaired oxygen uptake by
the cells. In addition, endotoxin makes the capillary walls
leaky at the site of infection; this becomes more general-
ized, allowing sodium and water to move from the inter-
stitial to the intracellular space. This eventually leads to
hypovolemia, making it indistinguishable from hypo-
volemic shock. Further cellular damage by endotoxins
causes the release of proteolytic enzymes, which paralyse
precapillary sphincters, enhance capillary leakage and
increase hypovolemia. The situation is aggravated by
the endotoxin acting as a negative inotrope on the
myocardium. It follows that in the late stage of sepsis
there are several causes of the shock state.
DISSEMINATED INTRAVASCULAR
Trauma, massive blood transfusion, infection, hypother-
mia, tissue injury and damage to the microvascular endo-
thelium are all common causes of DIC. Procoagulant tissue
factors such as IL-6 and TNFa are released, promoting
inappropriate intravascular activation of the coagulation,
fibrinolytic and complement systems. Both thrombin and
plasmin are activated but out of balance; as a result,
platelet-fibrin thrombi form in the microvasculature, while
fibrin degradation products are raised in the plasma.
Platelets are reduced in number and impaired in function;
coagulation and fibrinolytic factors are also reduced and
coagulation studies show prolongation of clotting time.
Coagulopathy resulting in vascular occlusion can
provoke end-organ ischaemia, infarction and failure. At
the same time it can lead to haemorrhage and uncon-
trolled bleeding at many sites, as in surgical wounds, the
skin, the pulmonary system, the gastrointestinal tract and
the cranium. Haemorrhagic complications usually domi-
nate in acute DIC following trauma.
MULTIPLE ORGAN FAILURE (MOF)
■y?-&s&x¥r?*W
■< '^£'i '■&:■&. i $z$&%tQz$x%z&&Q?g-&%?
;.f.5^.^:.lS^^. j^j;^; ^■'^^■^W^^i^^^i^B^S-^^-^ \
This is defined as the presence of altered function in two
or more organs in an acutely ill patient, such that inter-
vention is required to maintain homeostasis (Greek
homoios = like + stasis = standing; tendency to stable
state). It represents the final common pathway of many
disease processes, of which trauma is one. It is invariably
preceded by a condition known as the systemic inflam-
matory response syndrome (SIRS), characterized by two
or more of the following:
• Temperature >38° C or <36° C
• Tachycardia >90 beats per minute
• Respiratory rate >20 breaths per minute or PaC0 2
<4.3 kPa
• White blood count >12 x 10 9 l" 1 or < 4 x 10 9 l" 1 or >10%
immature (band) forms.
Key point
Multiple organ failure is a deadly condition
with a mortality rate of about 60%.
1 . The pathophysiology behind MOF has yet to be fully
elucidated. A 'one-hit model' accounts for early MOF as
a result of massive trauma. The initial insult triggers a
severe SIRS, leading to MOF. It was apparent that some
traumatized patients who had sustained non-massive
trauma developed delayed MOF. The 'two-hit model' was
developed to explain the occurrence of MOF in such
patients. In this model the initial injury primes the inflam-
matory machinery to a subclinical level. This gives rise to
the exaggerated response seen in MOF only if the patient
is subjected to a 'second hit', such as hypoxia, hypoten-
sion, infection, operation, anaesthesia or further trauma.
2. Irrespective of the actual cause, it is probable that a
stimulus such as injury or infection initiates the release of
a number of mediators by macrophages, monocytes and
endothelial cells. These include TNF, IL-1(3, IL-6 and IL-8.
Following 'relook' laparotomies (reoperations to identify
and correct any complications that have developed),
raised levels of IL-6 were found; this suggests that
cytokines may have a role in intensifying and perpetu-
ating the inflammatory state following such a 'second hit'.
These changes cause further white cell activation in addi-
tion to adhesion of leucocytes to endothelial cells lining
blood vessels. This occurs in virtually all organs of the
body, but particularly the lungs, liver and intestine. The
process leads to the migration of white cells into the inter-
stitial space, the release of proteases and oxygen radicals
and the activation of arachidonic acid. Such changes ex-
acerbate existing capillary damage, leading to widespread
leakage of fluid into the interstitial space. In addition,
arachidonic acid activation gives rise to prostacyclin,
thromboxane A 2 and leukotrienes.
3. Tissue damage is simultaneously resulting from
vasoconstriction and intravascular thrombosis in the
microvascular circulation. In the lungs, this can give rise
to right heart failure due to the increases in pulmonary
vascular resistance and pulmonary artery pressure.
33
2
EMERGENCY
4. In managing these patients, recognize that the
normal relationship between oxygen delivery to tissue
(Do 2 ) and oxygen consumption (Vo 2 ) is altered. In MOF,
partly because of the marked increase in Vo 2 , tissues
become flow dependent, that is reliant upon Do 2 (see
p. 30). Consequently, any hypovolemia, pulmonary
disease or myocardial dysfunction jeopardizes the deliv-
ery of oxygen even further, and so increases the degree of
tissue hypoxia and organ dysfunction.
Adult respiratory distress syndrome/acute
lung injury
Adult respiratory distress syndrome (ARDS) represents
the severe form of acute lung injury (ALI). Although only
approximately 2% of trauma patients develop ARDS, they
then have a mortality rate of approximately 40-50%.
ALI is a collective term for hypoxaemic respiratory
failure, characterized by the American-European con-
sensus as:
• Bilateral pulmonary infiltrates visible on chest X-ray
• Pulmonary capillary wedge pressure <18 mmHg
• Pao 2 /fio 2 <300.
In ARDS:
• Pao 2 /Ho 2 <200
Aetiology and pathogenesis
1. Acute lung injury can be caused by local or systemic
inflammation. In trauma patients it may result from direct
lung injury or, when the injured tissue is more distant, by
SIRS (see above).
2. Direct causes include pulmonary contusion, aspir-
ation of gastric contents, near drowning, inhalation of
toxic fumes, thermal injury to the respiratory tract,
bacterial or viral pneumonia, and radiation injury.
3. Indirect causes include sepsis, massive haemorrhage,
multiple transfusions, shock from any cause, DIC, massive
burns, major and multiple trauma, pre-eclampsia, amni-
otic fluid embolism, pancreatitis, head injuries and
cardiopulmonary bypass.
4. In addition, it has been suggested that any critical
illness that leads to inadequate cellular oxygenation can
precipitate the syndrome.
5. Regardless of the cause, pathogenesis follows a
common pathway (Fig. 2.7). Neutrophils adhere to the
vascular endothelium, then migrate into the interstitium
and alveolar airspaces. They release inflammatory medi-
ators that attract and activate other inflammatory cells,
stimulate the coagulation cascade and release oxygen free
radicals, producing widespread endothelial damage. As a
result of the increased capillary permeability, protein-rich
fluid occupies the interstitium and alveolar airspaces;
Direct lung
injury
Causative event
Indirect lung
injury
i
Neutrophils
Platelets
Macrophages
{all activated)
t
l
Widespread endothelial damage
t
Cell destruction and
death
i
ARDS and multiple organ failure
Fig. 2.7 A simplified flow chart illustrating the
development of ARDS.
this, coupled with the deactivation of surfactant, causes
stiff lungs with decreased compliance. The protein-rich
fluid, coupled with increased lung lymph flow, thickens
the alveolar capillary membrane, impairing oxygen dif-
fusion. In the later stages of the disease, fibrosis may
develop.
NEUROLOGICAL PATHOPHYSIOLOGY
"^S^-^W+S-^-'
Head injuries are common. In the UK head-injured
patients account for 7-10% of all emergency department
attendances, of whom 1 in 7 are admitted. Most serious
head injuries result from road accidents, falls and
assaults. Over 5000 people die from traumatic brain
injury in England and Wales every year. It is estimated
that a further 1500 patients survive to endure significant
lifelong morbidity. Remember that victims have a mean
34
TRAUMA
2
age of 30, so there is a major impact on society. The
combination of head injury and extracranial injury is
particularly dangerous, as the presence of hypoxia and
hypotension is associated with a 75% increase in mortal-
ity from severe head injury. This is partly the result of
impaired autoregulatory capacity of the injured brain,
resulting in the development of secondary brain injury.
Intracranial pressure
1. In the adult the neurocranium is a rigid box and its
volume is fixed. The intracranial pressure (ICP) generated
inside it depends on the volume of its contents. In the
normal state these consist of brain, CSF, blood and blood
vessels. Together, these produce an ICP of 5-13 mmHg
when the subject lies horizontally.
2. If the ICP is to be kept at normal levels, any increase
in the volume of one component must be accompanied by
a decrease in the other components. CSF can be displaced
into the spinal system and its absorption increased. The
volume of cerebral venous blood within the dural sinuses
can also decrease. Furthermore, the brain is a compliant
organ, so it can mould to accommodate changes. Once
the limit of these compensatory mechanisms is reached,
the ICP rises.
3. Head trauma results not only in mass lesions but
also in increased permeability of the intracerebral
microvasculature. This leads to interstitial oedema and
cerebral swelling, making the brain relatively 'stiff, so it
is less able to adapt to changes in the intracranial con-
tents. This situation deteriorates further if ventilation is
impaired, as hypoxia produces additional cerebral
swelling. Hypercarbia results in vasodilatation of the
blood vessels in the uninjured parts of the brain (see
below), thereby increasing intracranial pressure.
4. Alterations in the intracranial contents, including
haematoma, not only produce an elevated ICP but also
make the brain, CSF and blood less adaptable to any
further additions. Even a small rise in volume of the
intracranial contents now causes a steep rise in the ICP.
Eventually, the brain herniates downwards through the
defect between the edges of the tentorium, and this ten-
torial herniation causes ipsilateral (Greek ipsos = same)
pupillary dilatation (Illrd cranial nerve compression) and
contralateral (Latin contra = opposite) motor weakness
(corticospinal tract compression). As ICP rises further,
the brainstem is compressed within the foramen
magnum, causing coning, leading to ischaemia. This is
heralded by Cushing's reflex, described by the great
American neurosurgeon (1869-1939), which is usually
fatal:
a. Decreased respiratory rate
b. Decreased heart rate
c. Increased systolic blood pressure.
Cerebral perfusion
Adequate ventilation and cerebral perfusion are essential
to supply the brain with oxygenated blood. Perfusion
depends on a difference between mean arterial pressure
(MAP) and the resistance to blood flow due to the ICP:
cerebral perfusion pressure (CPP) = MAP - ICP.
In the multiply injured patient, not only is the ICP
rising because of the head injury, but the MAP may be
falling due to blood loss from an extracranial trauma. The
CPP is markedly reduced. If the CPP is 50 mmHg or less,
cerebral ischaemia develops; as described above, this
leads to additional brain swelling and further rises in ICP
as the cycle perpetuates itself. Make every effort to keep
CPP at greater than 70 mmHg, as this reduces mortality.
A CPP less than 30 mmHg is fatal.
Consciousness
Consciousness depends on an intact ascending reticular
activating system, contained within the midbrain and
brainstem, and an intact cerebral cortex. Interruption any-
where along this pathway, either structural or metabolic,
results in loss of consciousness. There are many possible
causes but the mnemonic (Greek mneme = memory)
'TIPPS on the vowels 7 recalls the important ones:
Trauma
Alcohol
Infection
Epilepsy
Poisons
Increase in ICP
Psychiatric
Opiates
Shock
Uraemia / metabolic
e
Key point
Eliminate hypoxia and hypovolaemia; each can
alone induce coma. If they are coupled with
head trauma, mortality increases.
An initial measure of consciousness is the patient's
response to stimulation. This is graded on the AVPU scale.
A
V
P
u
Alert
Responds to Voice
Responds to Pain
No response (Unconscious)
The Glasgow Coma Scale is a more complicated but vali-
dated assessment based on the patient's best eye, verbal
and motor responses to stimulation (Greek koma = deep
sleep). The scale (Table 2.7) is an objective measure of the
condition, used to monitor the patient's progress. The
three scores are added; the minimum score is 3 and any
score below 8 carries a poor prognosis.
35
EMERGENCY
Table 2.7
The
Glasgow Coma Scale
Eye opening
Score
Verbal response
Score
Motor response
Score
Spontaneous
4
Orientated
5
Obeys commands
6
To speech
3
Confused
4
Localizes to pain
5
To pain
2
Inappropriate words
3
Withdraws
4
None
1
Inappropriate sounds
2
Flexion to pain
3
None
1
Extension to pain
2
None
1
Fractures
Skull fractures usually result from direct trauma and are
classified as being linear, depressed or open. The term
'open' implies a direct communication between the
brain surface and either the scalp or mucous membrane
laceration.
Primary and secondary brain injury
1. Neurological cells may die as a result of energy
transferred to them by the injurious event - primary brain
injury. Possibly, progressive primary brain damage occurs
subsequently because of endogenous neurochemical
changes leading to further cellular injury. At present,
injury prevention is the only factor that reduces primary
brain damage.
2. Secondary brain injury is the neurological damage
produced by subsequent insults, such as hypoxia, hypo-
volaemia and elevation in ICP (remember CPP = MAP -
ICP), metabolic imbalance, seizures and later diffuse
brain swelling, and infection. Mortality can be reduced by
appropriate resuscitation to prevent secondary brain
injury.
3. A purely focal injury can follow a contact force.
However, there is usually sufficient associated diffuse
brain injury to produce an altered level of consciousness
from a temporary disruption of the reticular formation
(see above). Furthermore, a space-occupying lesion is
often accompanied by a swollen brain due to primary and
secondary brain damage. This accelerates the rise in
intracranial pressure and the development of additional
brain damage. Consequently, the trauma patient invari-
ably has diffuse and specific neurological injuries. The
clinical features of a focal injury depend on the site
injured, as different parts of the brain perform different
functions; diffuse brain injuries tend to be bilateral.
4. Selective herniation of the cerebellum through the
foramen magnum can be produced by an expanding pos-
terior fossa intracranial haematoma. This is the only cere-
bral haematoma to produce neurological damage without
a preceding deterioration in consciousness level. (See
above for tentorial and brainstem herniation.) Among the
features, the most common are pupillary dilatation,
respiratory abnormalities, bradycardia, head tilt and
cranial nerve palsies. Most alarming is sudden respiratory
arrest resulting from distal brainstem compression. It is a
rare condition but consider it early, especially in patients
with an occipital fracture.
Concussion
Concussion (Latin con = together + quatare - to shake)
occurs when the head is subjected to minor inertial forces.
The patient is always amnesic of the event and there may
also be retro- and antegrade amnesia. A transient loss of
consciousness may occur, usually less than 5 min. These
patients show no localizing signs but may have nausea,
vomiting and headache. It was at first thought that no
organic brain damage occurred but this is found not to be
the case: microscopic changes occur, and, while the net
effect of one episode is minor, the effect of further
episodes can be cumulative.
Diffuse axonal injury (DAI) and contra coup
injury
1. Diffuse axonal injury results from widespread,
mainly microscopic, disruption of the brain, consisting of
axonal damage, microscopic haemorrhages, tears in the
brain tissue and interstitial oedema. Consequently, it can
cause prolonged periods, for days or weeks, of coma and
has an overall mortality rate of 33-50%. Autonomic dys-
function is common, giving rise to high fever, hyperten-
sion and sweating.
2. The brain that lies beneath the impact point of a
contact force is subjected to a series of strains resulting
from the inward deformation of bone and the shock
waves spreading from the site of impact. The base of the
brain can be strained if it impinges on projections on the
base of the skull, producing gross neurological damage,
with haemorrhages, neuronal death and brain swelling.
Consciousness is invariably lost at the time of the incident
and neurological signs develop by the time it is regained.
Common signs are altered level of consciousness, hemi-
paresis, ataxia and seizures.
3. The brain is not fixed within the neurocranium but
floats in a bath of CSF, tethered by the arachnoid fibres
36
TRAUMA
r 2
and blood vessels. As the head moves because of an accel-
erating or decelerating force, the skull, and then the brain,
moves in the direction of the force. Consequently, strains
develop in the brain tissue and small blood vessels oppo-
site the impact point, producing the contusional changes
previously described. Additionally, the brain continues to
move until it impacts against the opposite side of the skull
or its base, thus injuring it in two places, most severely at
the site furthest from the impact; this is a contra coup injury
(French = counterblow).
Acute intracranial haematoma
1 . Most extradural haematomas (EDHs) develop in the
temporoparietal area following a tear in the middle
meningeal artery. Much less commonly, they result from
torn venous sinuses within the neurocranium. Compared
to a venous cause, an arterially produced extradural
haematoma develops quickly, producing a rapid rise in
intracranial pressure.
2. The 'classic' presentation (Fig. 2.8) occurs in only
one-fifth of patients. Some may be unconscious from the
time of the impact, others do not lose consciousness at the
time but later develop neurological features. Most com-
monly there is a deterioration of consciousness, pupil-size
changes or a focal weakness.
Acute intradural haematoma (IDH)
1. This incorporates both subdural (SDH) and intra-
cerebral (ICH) haematomas, which frequently coexist, and
are 3-4 times more common than extradural haematomas.
Subdural haematomas usually develop in the temporal
lobe and may be bilateral. Following application of an
inertiai force, some of the bridging veins tear and blood
collects in the subdural space. Occasionally, a subdural
haematoma develops without an accompanying intra-
cerebral haematoma. Solitary intracerebral haematomas
rarely develop in the frontal lobes.
2. Small intracerebral haematomas may result from
inertiai forces, and increase in volume over time.
Depending on their location, they may cause localizing
signs or a rise in the intracranial pressure, with deterio-
ration in the patient's clinical state.
3. The forces needed to produce an intracerebral
haematoma are greater than those needed to produce an
extradural haematoma, so an intracerebral haematoma is
usually associated with cerebral contusion and cortical
lacerations. Consequently, the patient commonly loses
consciousness immediately and may also exhibit focal
signs such as contralateral hemiparesis (Greek parienai =
to relax), unilateral pupil dilatation or focal fits. With a
solitary subdural haematoma, an initial lucid period may
be followed by deteriorating neurological state. This
develops more slowly than following an extradural
haematoma because the bleeding is venous rather than
arterial. Tears of only a few bridging veins, in the pres-
ence of brain atrophy with enlargement of the intracranial
space, may delay development of symptoms for several
days.
Subarachnoid haemorrhage (SAH)
This occasionally follows a head injury. The patient often
develops severe headaches and photophobia, but other
signs of meningism can occur. Do not test for neck
stiffness until cervical spine injury has been ruled out
clinically and radiologically (see Ch. 1).
SPINAL INJURIES
In the UK, 10-15 people per million of the population
suffer spinal injuries each year (Table 2.8). The common-
est site is the cervical spine (55%), mainly because most
people are injured following a road traffic accident
(48%).
Table 2.8 Sites of spinal injuries
Site
Blunt trauma
(%)
Penetrating trauma
Cervical
Thoracic
Lumbar
Multiple
55
35
10
10
24
56
20
• Transient loss of consciousness at the time of the injury from a momentary disruption of the
reticular formation.
• Patient then regains consciousness for several hours j the lucid period,
m Localizing signs develop with neurological deficits, headache and eventually
unconsciousness from the developing EDH, which causes the ICP to rise.
Fig. 2.8 Classic history of an extradural haematoma (EDH).
37
EMERGENCY
Primary neurological damage
1. This results directly from the initial insult, usually
from blunt trauma, producing abnormal movement in the
vertebral column. Severe trauma may lead to ligamental
rupture and vertebral fractures, reducing the space
around the spinal canal and allowing bone and soft tissue
to impinge directly on the cord. The potential space
around the spinal cord may already be small, increasing
the chance of neurological damage.
2. Less commonly, penetrating trauma, as by stabbing,
causes primary spinal damage. Much more extensive
areas of destruction and oedema result when the spinal
cord is subjected to a large force such as a gunshot.
Secondary neurological damage
1. The three common causes of damage following the
initial injury are mechanical disturbance of the back,
hypoxia and poor spinal perfusion. These effects are
additive.
2. Hypoxia can result from any of the causes men-
tioned above, but significant spinal injury alone can cause
it (Table 2.9). The underlying problem is usually a lack of
respiratory muscle power following a high spinal lesion.
Lesions above T12 denervate the intercostal muscles.
Injuries above the level of C5 also block the phrenic nerve,
paralysing the diaphragm.
3. Inadequate spinal perfusion results either from
general hypovolaemia or failure of the spinal cord to
regulate its own blood supply following injury. A fall in
mean arterial pressure therefore produces a reduced
spinal perfusion. Conversely, if the pressure is increased
too far it may produce a spinal haemorrhagic infarct.
Secondary damage leads to interstitial and intracellular
Table 2.9 Respiratory failure in spinal injury
Tetraplegic
Paraplegic
Intercostal paralysis
Phrenic nerve palsy
Inability to expectorate
V/Q mismatch
Intercostal paralysis
oedema, further aggravating the deficient spinal perfu-
sion. As this oedema spreads, compressing neurons, it
produces an ascending clinical deterioration. In cases of
high spinal injury this process can lead to secondary res-
piratory deterioration.
Partial spinal cord injury
Anterior spinal cord injury results from direct compres-
sion or obstruction of the anterior spinal artery. It affects
the spinothalamic and corticospinal tracts (Fig. 2.9), result-
ing in loss of coarse touch, pain and temperature sensa-
tion, and flaccid weakness. This type of injury is associated
with fractures or dislocations in the vertebral column.
Central spinal cord injury usually occurs in elderly
patients with cervical spondylosis. Following a vascular
event the corticospinal tracts are damaged, resulting in
flaccid weakness. Because of the anatomical arrangement
in the centre of the cord, the upper limbs are more affected
than the lower.
Sacral fibres in the spinothalamic tract are positioned
laterally to corresponding fibres from other regions of the
body (Fig. 2.9). It follows that anterior and central
injuries, which primarily affect the midline of the spinal
Dorsal columns (cutaneous sensation
and proprioception from ipsi lateral)
Lateraf corticospinal tract
(cross motor fibres)
Dorsal spinothalamic tract (pain
and temperature sensation from
opposite side of body)
Ventral spinothalamic tract (crude touch
and pressure from opposfte side of body)
S: sacral area
L: lumbar area
T: thoracic area
C; cervical area
Posterior spinocerebellar tract
Anterior spinocerebellar tract
Anterior corticospinal tract (uncrossed motor fibres)
Fig. 2.9 Cross-section of the spinal cord demonstrating the longitudinal tracts. (With permission from Driscoll P,
Gwinnutt C, Jimmerson C, Goodall O. In: Trauma resuscitation: the team approach, Macmillan Press Ltd).
38
TRAUMA
cord, may not affect the sacral fibres. This 'sacral sparing'
produces sensory loss below a certain level on the trunk,
with retention of pinprick appreciation over the sacral
and perineal area.
Lateral spinal cord injury (Brown-Sequard syndrome)
is the result of penetrating trauma. All sensory and motor
function is lost on the side of the wound at the level of the
lesion. Below this level there is contralateral loss of pain
and temperature sensation with ipsilateral loss of muscle
power and tone.
Posterior spinal cord injury is a rare condition, result-
ing in loss of vibration sensation and proprioception.
Spinal shock
1. This totally functionless condition occasionally
occurs following spinal injury. The features are general-
ized flaccid paralysis, diaphragmatic breathing, priap-
ism, gastric dilatation and autonomic dysfunction
associated with neurogenic shock. The English neurolo-
gist CE. Beevor (1854-1908) described movement of the
umbilicus when the abdomen is stroked, resulting from
paralysis of the lower rectus abdominis muscle.
2. This state can last for days or weeks, but areas of the
cord are still capable of a full recovery. Permanent
damage results in spasticity once the flaccid state
resolves. Upper motor neuron reflexes return below the
level of the lesion following complete transection of the
cord, producing exaggerated responses to stimuli;
however, sensation is lost.
3. During this stage there is risk of pressure sores, deep
venous thrombosis, pulmonary emboli and acute peptic
ulceration with either haematemesis or, occasionally,
perforation.
FRACTURES
1 . Fracture occurs in normal bone as a result of trauma.
The type of fracture depends on the direction of the viol-
ence. A twisting injury causes a spiral or oblique fracture,
a direct blow usually causes a transverse fracture, axial
compression frequently results in a comminuted (Latin
minuere = to make small) or burst fracture.
2. Stress fractures occur when the underlying bone is
normal. It is the repetitive application of an abnormal
load that causes the bone to fracture. The load alone is not
sufficient to cause the fracture but rather the cumulative
effect of repeated loading. It is most frequently seen in
individuals undertaking increased amounts of unaccus-
tomed exercise, such as the 'march' metatarsal fracture in
army recruits and dancers.
3. Pathological fractures occur when the underlying
bone is weak, perhaps from metastatic cancer or
metabolic bone disease; as a result it gives way under
minimal trauma.
Fracture repair
1. When a fracture occurs, not only is the bone broken
but the encircling tissues are also damaged. The bone
ends are surrounded by a haematoma including these
injured tissues. Within hours an aseptic inflammatory
response develops, comprising polymorphonuclear leu-
cocytes, lymphocytes, macrophages and blood vessels,
followed later by fibroblasts. Within this organized frac-
ture haematoma, bone develops either directly or follow-
ing the formation of cartilage with endochondral
ossification. At the same time osteoclasts resorb the
necrotic bone ends. The initial bone that is laid down
(callus) consists of immature woven bone, which is gradu-
ally converted to stable lamellar (Latin lamina - a thin
plate) bone with consolidation of the fracture. Resorption
occurs within the bone trabeculae as recanalizing
haversian systems (described by the English physician
C. Havers 1650-1702) bridge the bone ends.
2. There are two types of callus. Primary callus results
from proliferation of committed osteoprogenitor cells in
periosteum and bone marrow. They produce directly
membranous bone, a once-only phenomenon limited in
duration. The second callus is inductive or external callus,
derived from the surrounding tissues, formed by pluri-
potential cells. A variety of factors, including mechanical
and humoral factors, may induce these mesenchymal
cells to differentiate to cartilage or bone.
3. The mediators for callus formation are not fully
understood. Probably the fracture ends emit osteogenic
substances, such as bone morpho genetic protein, into the
surrounding haematoma. This is in addition to mediators
such as IL-1 and growth factors released from the fracture
haematoma. Angiogenic factors probably play an import-
ant role in the vascularization of the fracture haematoma.
4. Movement of the fragments increases the fracture
exudate. Rigid fixation minimizes the granulation tissue
and external callus and may retard the release of mor-
phogens and growth factors from the bone ends.
Reaming of the intramedullary canal may cause addi-
tional bone damage. Weight bearing stimulates growth
factors and prostaglandins, which act as biochemical
mediators.
PERIPHERAL NERVE|NJURY
1. Blunt trauma to a nerve may produce a temporary
block in the conduction of impulses, leaving the axonal
transport system intact. The axon distal to the injury
survives and complete functional recovery can be expected;
39
2
EMERGENCY
this is neuropraxia (Greek a = not + prassein = to act). More
severe trauma will interrupt axonal transport and cause
wallerian (Augustus Waller 1816-1870) degeneration: the
distal axon dies, the myelin sheath disintegrates and the
Schwann cells turn into scavenging macrophages which
remove the debris. The cell body then embarks on a pre-
programmed regenerative response which is usually
known as chromatolysis, as it involves the disappearance of
the Nissl's granules which are the rough endoplasmic reti-
culum of the normal cell. An entirely new set of ribosomes
appears, dedicated to the task of reconstruction. By their
efforts, axon sprouts emerge from the axon proximal to the
lesion and grow distally. Injury of this severity is known as
axonotmesis (Greek tmesis = a cutting apart). It eventually
produces a good functional result because the endoneurial
tubes are intact and the regenerating axons are therefore
guaranteed to reach the correct end organs.
2. Laceration or extreme traction producing neuro-
tmesis also leads to wallerian distal degeneration and
proximal chromatolysis - loosening of the chromatin of
cell nuclei, followed by either cell death or axonal regen-
eration. In this case, however, the final functional result is
bound to be much worse than in any injury that leaves the
endoneurial tubes intact. Not only do the axon sprouts
have to traverse a gap filled with organizing repair tissue,
but each one needs to grow down its original conduit at
a rate of approximately 1 mm per day Axons failing to
enter the distal stump may form a tender neuroma, often
producing troublesome symptoms. Progress can be mon-
itored clinically using the sign described by the French
neurologist Jules Tinel (1879-1952), These are electric feel-
ings in the territory of the nerve produced by light per-
cussion over regenerating axon tips, whether in the distal
portion of the nerve or in a neuroma.
3. Motor axons are capable of producing collateral
sprouts once they enter muscle, leading to abnormally
large motor units with relatively good return of strength.
Sensory axons often fail to reinnervate the specialized
receptors forming the basis for the sense of touch and this,
together with the mismatching of axons with conduits,
invariably results in poor sensory recovery except in the
very young. The functional result in the hand is poor.
Compartment syndrome
This specific type of neurovascular compromise can occur
as part of any extremity injury. Although commonly
caused by fractures and soft tissue injuries, the presence
of a fracture is not essential. It is a progressive condition
in which the elevated tissue pressure within a confined
myofascial compartment exceeds capillary pressure,
leading to vascular compromise of the muscles and
nerves. It can result from a variety of causes, categorized
as either expansive or compressive.
External compression of compartment
• Constricting dressing or cast
• Closing fascial defects
• Third degree, full thickness, burns.
Expansion of compartment contents
• Haemorrhage and oedema following fractures or soft
tissue injuries
• Haemorrhage following coagulopathy or vascular
laceration
• Postischaemic swelling.
The four compartments of the lower leg are the most com-
monly involved areas, but it can occur in the shoulder,
arm, forearm, hand, buttock, thigh or abdomen (follow-
ing trauma or surgery).
Key points
• Continuously monitor at-risk sites in order to
detect and correct impeding compartment
syndrome (Table 2.10).
• Increasing pain, exacerbated by passive flexion
and extension, is a reliable combination
signalling compartment syndrome.
1. Detect the condition in the early, potentially
reversible stage or muscle may infarct, giving rise to
rhabdomyolysis, hypovolemia, hyperkalaemia, hyper-
phosphataemia, high levels of uric acid, metabolic acido-
sis, renal failure and death. Locally fibrotic contractures
may develop.
2. Detection should be clinical but the intracompart-
mental pressure can be monitored when clinical assess-
ment is difficult or if you are in doubt about the clinical
Table 2.10 Features of impending or established
compartment syndrome
Early
Pain in the limb
Pain on passive movement of the distal joints
Paresthesia
Loss of distal sensation
Late
Tension or swelling of the compartment
Absent muscle power
Very /ate
Absent pulse pressure in the distal limb
40
TRAUMA
2
features. Examples of such cases are when the patient is
unresponsive because of neurological injury or sedation,
or has a nerve defect from other causes / or has a regional
nerve block. Use it as an adjunct to, not a replacement for,
clinical monitoring.
3. Absolute pressure values are unreliable because per-
fusion is dependent upon the difference between the arte-
rial blood pressure and the compartmental pressure. A
difference of less than 30 mmHg between diastolic blood
pressure and compartment pressure is recommended as
a threshold for releasing the tension by carrying out
fasciotomy. A fall in the distal pulse pressure is a very
late sign and indicates imminent tissue ischaemia. Pulse
oximetry is not a reliable help in diagnosing or monitor-
ing impaired perfusion secondary to raised compartment
pressure.
4. Myoglobinuria and raised plasma myoglobin result
not only from direct myocyte damage but also from
polymorphonuclear neutrophil-mediated cell lysis and
microvascular coagulation.
Acute renal failure complicates severe crush injury as
a result of hypovolaemia leading to prerenal failure,
while the released myoglobin from damaged muscle cells
precipitates and obstructs flow in the renal tubules.
Myoglobin and macrophage-generated cytokines experi-
mentally induce levels of potent vasoconstrictors such as
platelet activating factor and endothelins, causing renal
arteriole constriction, decreased glomerular filtration and
renal ischaemia. A high concentration of myoglobinuria
produces a red or smoky brown discoloration of the
urine. Look for this when you catheterize the patient and
check the urine regularly.
CRUSH SYNDROME
1. Crush injuries occur in a variety of ways: for
example, in patients becoming trapped under fallen
masonry or in a car following a road traffic accident. The
patient's own body weight may be sufficient to compress
the tissue if the consciousness level is depressed for a con-
siderable time. Severe beatings and epileptic seizures may
also be responsible.
2. They present both local and systemic problems. The
local injury may be complicated with compartment syn-
drome. Systemic concerns include intravascular volume
depletion, electrolyte imbalance and renal injury from
myoglobin. Until the limb is released there is little sys-
temic effect; once reperfusion starts, plasma and blood
leak into the previously crushed soft tissues as a result of
the increased capillary membrane permeability and
vessel damage. The effect depends upon the degree of
tissue damage and in severe cases may produce hypo-
volaemia. Devitalized tissue is at high risk of secondary
infection with a further systematic release of toxins.
3. Abnormal systemic blood markers of muscle infarc-
tion include rising blood urea nitrogen, raised potassium,
phosphate, uric acid and creatine kinase. Metabolic
acidosis develops with an increased anion gap.
Hypocalcaemia occurs although intracellular calcium is
raised. The packed cell volume is raised but there is
thrombocytopenia.
fr"*
Key point
• The sudden rise in serum potassium
concentration may produce cardiac arrhythmias
(and arrest) soon after the patient is released.
FAT EMBOLISM SYNDROME
1. Ninety per cent of cases result from blunt trauma
associated with long bone fractures. It has, however, also
been reported following burns, decompression sickness
and even liposuction!
2. The classical triad of respiratory failure, neurologi-
cal dysfunction and petechial rash is not present in all
cases; indeed the rash, though pathognomonic, is only
present in 50% of cases.
3. As several organs can be affected, there is a wide
range of possible clinical presentations, although dysp-
noea is the commonest. The onset of symptoms is usually
between 24 and 48 h postinjury. Pulmonary changes
include ventilation-perfusion (V/Q) mismatch, impaired
alveolar surfactant activity and segmental hypoper-
fusion. Shadowing on chest X-ray is not dissimilar to
ARDS. Neurological changes occur as a result of hypoxia
and /or the humoral and cellular factors released from
the bone. Effects on the heart may result in a fall in
mechanical performance and arrhythmias. Renal damage
can lead to lipiduria with tubular damage and ischaemic
glomerular-tubular dysfunction.
4. Lipid globules are formed mainly from circulating
plasma triglycerides, carried by very low density lipopro-
teins (VLDLs). In trauma, this is commonly a result of
the release into the circulation of lipid globules from
damaged bone marrow adipocytes; however, it can also
occur with increased peripheral mobilization of fatty
acids and increased hepatic synthesis of triglycerides or
reduced peripheral uptake of plasma VLDLs (Fig. 2.10). It
gives rise to thromboembolism of the microvasculature,
with lipid globules and fibrin-platelet thrombi. In addi-
tion, the local release of free fatty acids can cause a severe
inflammatory reaction that initiates the SIRS chemical
41
2
EMERGENCY
t
Clearance
t
Bone marrow
release
Plasma
triglycerides
{Erythrocytes {0 2 transport)
Platelets {aggregation}
White cells {cytokines)
Vascular endothelium
(coagulopathy)
Multi-organ
system
dysfunction
Fig. 2.10 The mechanism of interaction between raised plasma triglycerides and the pathogenesis of multiorgan
system dysfunction in fat embolism.
cascade, which is probably responsible for the high asso-
ciation of fat emboli syndrome with both progressive
anaemia and pyrexia (> 38.5° C).
Key point
Diagnosis of fat embolism rests on identifying
fat globules in body fluids, histological
recognition, or pulmonary involvement with at
least one other organ system dysfunction.
5. Search for fat globules in body fluids, such as
sputum and urine, or lipid emboli in retinal vessels on
fundoscopy; histological diagnosis requires demonstra-
tion of intracellular and intravascular aggregation of lipid
globules with Sudan black stain.
PATHOPHYSIOLOGY OF WOUND
HEALING
Soft tissue injuries heal by a complex series of cellular
events that lead to connective tissue formation and repair
by scar formation. Three fundamental things must
happen for wound healing to occur: (1) haemostasis must
be achieved; (2) an inflammatory response must be
mounted in order to defend against microbial infection as
well as attracting and stimulating the cells needed for
tissue repair; and (3) many different cells must proliferate
and synthesize the proteins necessary for restoring
integrity and strength to the damaged tissue. This is
covered in more detail in Chapter 33.
Wound healing therefore requires:
• Haemostais
• Inflammation
• Cell proliferation and repair.
Wound contracture
When wounds with tissue loss are left to heal by
secondary intention, contraction of granulation tissue
reduces the size of the tissue defect. The cell responsible
for this process is the myofibroblast, although the exact
role of this cell is unresolved. Even though reducing the
size of the tissue deficit is of benefit in wound healing, the
distortion and scar formation produced by the process
inhibit function in certain areas of the body (particularly
on the face and around joints).
PATHOPHYSIOLOGY^
Three risk factors for death after burn injury have been
identified: age more than 60 years; burn surface area of
more than 40%; and the presence of inhalational injury.
Increased fluid losses due to uncontrolled evaporation
are coupled with fluid shifts for the first 24-48 h after a
major burn. Leakage of intravascular water, salt and
protein occurs through the porous capillary bed into the
interstitial space. This, in turn, results in loss of circulat-
ing plasma volume, haemoconcentration and hypo-
volaemia, the severity of which increases with the
severity of the burn. In a burn over 15% of the total body
surface area (TBSA), the capillary leak may be systemic,
causing generalized oedema and a significant fall in blood
volume.
Shock associated with burn injuries
The effect on the circulation is directly related to the size
and severity of the burn wound. The body compensates
for this loss of plasma with an increase in peripheral
vascular resistance, and the patient will appear cool,
pale and clammy; however, this compensation will only
be effective in maintaining circulation for a period of
time, depending on the severity of the burn and the
42
TRAUMA
r 2
presence of other injuries. Ultimately, the patient will
demonstrate signs of hypovolemic shock as the cardiac
output falls. During this time it is rarely possible to keep
the circulating volume within normal limits. The end of
the shock phase in the adequately resuscitated burn
patient is usually marked by a diuresis. This occurs
approximately 48 h after the burn and is usually associ-
ated with a fluid balance that is more like that of an
uninjured individual.
A burn of greater than 15% TBSA almost always
requires intravenous fluid administration to expand the
depleted vascular volume. However, shock can occur
with a burn involving as little as 10% TBSA, as a result of
complicating factors such as age, pre-existing disease and
other major injuries. In these circumstances, a burn of
25^0% becomes a potentially lethal injury Numerous
fluid regimens have been calculated to assist in burn
resuscitation: it is sensible to use the regimen favoured by
your local burns department.
Depth of burn and cause of burn
The diagnosis of the depth of burn is not always easy. If
doubtful, it should be reassessed at 24 h, using non-
adherent dressings between examinations.
Superficial burns
Superficial burns are characterized by erythema, pain and
the absence of blisters. Typical examples of superficial
burns would be sunburn or simple flashburns. The
epithelium remains intact so infection is not usually a
problem and they generally do not require fluid replace-
ment. Healing takes place over a few days and, with the
exception of some pigmentation changes, no scarring
occurs.
Partial thickness burns
Superficial partial thickness and deep partial thickness
burns have been described. In the superficial variety the
epidermis and the superficial dermis are burnt. They
appear pink, moist and have fluid-filled, thin-walled
blisters. They are associated with more swelling and are
painfully sensitive, even to air current. Healing is by
epithelialization from the pilosebaceous and sweat
glands, as well as the wound edges. Therefore healing is
often prolonged to 3^ weeks.
In deep partial thickness burns the reticular dermis is
involved. The appearance is a mixture of red and white,
with blistering also a feature. The capillary refill is often
prolonged and two-point discrimination may well be
diminished. Healing is from the few remaining epithelial
appendages and can take up to 6 weeks. It results in poor
quality skin and marked pigmentation change (either
hyper- or hypopigmentation). Hypertrophic scar forma-
tion may be a problem, as can wound contraction.
Infection may complicate the recovery of any partial
thickness burn because the epithelium has been breached.
This may take the form of locally delayed wound healing
or sytemically-induced multiorgan failure (MOF). Deep
dermal burns can result from scalds, contact burns,
chemical burns and flame burns.
Full thickness burns
Full thickness burns involve the destruction of both the
epidermis and dermis. They appear white, leathery and
have no sensation to pinprick. The diagnosis between
deep dermal and full thickness burns can be difficult, as
they commonly lie adjacent to each other within the same
wound. They can only heal naturally by epithelialization
from the wound edge, leaving a contracted, poor quality
scar. In the acute situation, circumferential full thickness
burns around limbs and the chest can act as tourniquets,
impeding the distal circulation and respiration, respect-
ively. Urgent escharotomy may be required in these
situations so discuss the possibility early with the local
burns centre (see Ch. 24).
Simplistically, the depth of a burn is a product of the
injurious temperature and the contact time. Thus the arm
of an alert individual exposed to a hot flame, and quickly
removed, will cause damage similar to that in a comatose
patient lying against a warm radiator. The young and
elderly are similarly immobile and prone to deep burns
from relatively innocuous hazards (e.g. hot bathwater).
Patients with peripheral neuropathies (e.g. diabetics) may
also present with unexpectedly severe contact burns.
Chemical injury, such as that due to hydrofluoric acid
or strong bases, can give rise to full thickness burns
requiring specialist treatment. A high index of suspicion
is appropriate when dealing with electrical burns because
current flows preferentially through the deep structures,
and extensive tissue damage may not be evident on early
superficial inspection.
Patients with full thickness burns may require blood
transfusion, as red cell haemolysis occurs with direct
thermal injury; indeed there is generalized fragility of the
entire red cell population leading to reduced cell lifespan.
Toxic shock syndrome
Toxin-producing strains of staphylococcal or streptococ-
cal bacteria can colonize wounds. A marked cytokine
43
2
EMERGENCY
response is stimulated, leading to a severe systemic illness
typified by:
• Pyrexia (usually >39° C)
• Vomiting and /or diarrhoea
• Rash (erythematous, maculopapular)
• Malaise, dizziness, peripheral shutdown or frank
shock.
It can occur even with relatively small, superficial burns
and is more common in children. Treatment is with
oxygen, intravenous fluids and antibiotics.
Response of the respiratory system to
inhalational injury
The upper airway may receive thermal burns, and tissue
swelling can develop very rapidly in these vascular
tissues. Injury to the mouth and oropharynx in particular
can cause acute respiratory obstruction. Oedema from
these injuries may also involve the vocal cords. Dramatic
changes in the patient's ability to maintain the airway
have been observed over a short period of time following
this type of injury. The lungs themselves are rarely injured
from 'burning'. Usually laryngeal spasm occurs from the
heat of the inspired gases, thereby protecting the lower
airway and lungs from exposure; however, steam, with a
heat capacity approximately 4000 times that of dry air, can
carry heat to the lower airways, resulting in significant
distal thermal injury.
Smoke inhalational injury secondary to confinement in
a house fire may be associated with a wide variety of
concomitant chemical injuries; for example, plastic fur-
niture and textiles will release hydrogen chloride. Not
only does this cause irritation to the eyes and throat but
it also causes severe pulmonary oedema. Phosgene,
produced from the burning of polyvinyl chloride, is
also associated with the development of significant
pulmonary oedema. Burning mattresses can produce
nitrogen dioxide.
As fires can produce such a wide variety of chemicals,
the resultant pulmonary damage may be multifactorial.
This may result in necrosis of respiratory epithelium,
inactivation of the respiratory cilia, and destruction of
type II pneumocytes and alveolar macrophages. This
leads to a decrease in lung compliance, which is seen as
an increase in the work of breathing and an impairment
of diffusion through the alveolar membrane.
In view of the very large surface area of the lung, fluid
requirements for resuscitation may increase by as much
as 50% of the calculated values if a severe inhalation
injury has been sustained. The severity of the injury
will not be related to the TBSA burn size, but rather to
the length of time and intensity of exposure to the
inhalation. Accurate information from the prehospital
care providers relative to these conditions is vital in
planning the patient's care and anticipating respiratory
complications.
Carbon monoxide poisoning
Systemic absorption of inhaled toxins may also occur.
Carbon monoxide (CO) is reported to be the leading toxi-
cological cause of death. Burning any carbon-containing
material can release CO, a byproduct of incomplete com-
bustion. The mechanisms of CO toxicity are multiple. CO
competes with oxygen for binding with haemoglobin,
myoglobin and cellular cytochrome oxidase. In addition,
off-loading of oxygen to the tissues is impaired by the
leftward shift of the oxygen-dissociation curve induced
by carboxyhaemoglobinaemia. The result is profound
hypoxia both in the intra- and extracellular environ-
ments. The areas most affected are those with a high
metabolic rate: heart and brain. Fetal tissue is also at
significant risk.
Measured carboxyhaemoglobin levels do not neces-
sarily correspond to clinical symptoms. The duration of
the patient's exposure to CO is significant, as short expos-
ures to a high concentration may give high carboxy-
haemoglobin levels but not cause significant metabolic
effects (usually acidosis with bicarbonate deficit).
Carboxyhaemoglobin levels greater than 10% are signi-
ficant and levels greater than 50% are generally lethal.
Early treatment with high concentration oxygen is
essential.
Carbon monoxide intoxication is the biggest cause of
death in people caught in house fires or other types of
closed-space fires.
Cyanide poisoning
When the polyurethane foam in modern furniture burns,
a thick black smoke is produced. This not only contains
CO and the corrosive substances mentioned above
but also cyanide gas. The latter is another metabolic
poison which binds to mitochondrial cytochrome oxidase.
This leads to inhibition of adenosine triphosphate (ATP)
production, with rapid onset of profound cellular anoxia
and death. Cyanide gas is difficult to measure but should
be assumed to be present if the carbon monoxide level is
greater than 10%. Severe metabolic acidosis and raised
44
TRAUMA
2
lactate levels found on arterial blood gas analysis provide
further clues towards the diagnosis.
TRAUMA SEVERITY SCORING
Essentially two separate types of trauma score have been
developed. One type is based on the anatomical injuries
sustained by the patient, while the other makes use of
physiological data taken from the patient at first contact.
They have developed in an attempt to achieve two sep-
arate objectives: firstly, to predict the probability of sur-
vival of an individual patient; and, secondly, to compare
outcomes between different hospitals, or the same hospi-
tal over time.
The Injury Severity Score (ISS) is an anatomical scoring
system that gives an overall score for patients with mul-
tiple injuries. The body is divided into six regions. Within
each region every injury is given an Abreviated Injury
Scale (A IS) score. This is a predetermined score from
1 (minor) to 6 (unsurvivable). The three highest grading
scores, which are found in separate regions, are squared
and then added together to make the final score. An
obvious deficiency in this model is that it does not take
account of multiple injuries within one body region. More
recent scores such as the New Injury Severity Score (NISS)
have been developed in an attempt to take account of
such inaccuracies.
The Revised Trauma Score (RTS) is a physiological
scoring system which attempts to predict outcome based
on the first set of data obtained on the patient. The timing
of first data recording and the effect of any treatment pre-
viously instigated will have a variable effect. None the
less, it has been shown to correlate well with the proba-
bility of survival. It is calculated by combining three
separately weighted scores based on the observed GCS,
respiratory rate and systolic blood pressure,
TRISS determines the probability of survival of a
patient by combining the ISS and RTS along with weight-
ings to take account of the patient's age and the mechan-
ism of injury (i.e. blunt or penetrating). The weightings
have been calculated from a large database of trauma
victims and allow comparative audit to be carried out.
ACKNOWLEDGEMENTS
Thanks are due to Geraldine M c Mahon, Richard Cowie,
Charles Galasko, Roop Kishen, Roderick Little, David
Marsh, Mohamed Rady, Stewart Watson and David Whitby.
Summary
• Trauma is an important clinical and
economic problem because it is a major
cause of mortality and morbidity in all
countries of the world.
• In order to be effective in trauma care, the
clinician needs a good understanding of
the biomechanics of injury and how they
relate to specific anatomical regions of the
body.
• The clinician also needs to be aware of
both the physiological and
pathophysiological response to trauma, as
this has direct implications for optimum
patient resuscitation.
• These anatomical and physiological
assessments can be used to quantify the
severity of the trauma so that comparisons
between treatment methods can be made.
References
Department of Health 1998 Our healthier nation - a contract for
health. DoH, London
Further reading
Beal AL, Cerra FB 1994 Multiple organ failure syndrome in the
1990s. JAMA 271 :226-233
Burgess AR, Eastridge BJ, Young JW et al 1990 Pelvic ring
disruptions: effective classification system and treatment
protocols. Journal of Trauma 30: 848-856
Colucciello S 1995 The treacherous and complex spectrum of
maxillofacial trauma: etiologies / evaluation and emergency
stabilisation. Emergency Medicine Reports 16: 59-70
Committee on Trauma 1997 Head trauma. In: Advanced trauma
life support manual. American College of Surgeons, Chicago,
pp 181-206
Committee on Trauma 1997 Biomechanics of injury. In:
Advanced trauma life support manual. American College of
Surgeons, Chicago, pp 345-366
Demling RH, Seigne P 2000 Metabolic management of patients
with severe burns. World Journal of Surgery 24: 673-680
Foex BA 1999 Systemic responses to trauma. British Medical
Bulletin 55: 726-743
Greenberg C, Sane D 1990 Coagulation problems in critical care
medicine. Critical Care: State of the Art 11: 187-194
45
2 .
EMERGENCY
Grundy D, Swain A 1997 ABC of spinal cord injury, 3rd edn.
British Medical Journal, London
Irving M, Stoner H 1987 Metabolism and nutrition in trauma.
In: Carter D, Polk H (eds) Butterworths international medical
reviews: trauma surgery 1. Butterworths, Oxford, pp 302-314
Lee CC, Marill KA, Carter WA, Crupi RS 2001 A current
concept of trauma-induced multi-organ failure. Annals of
Emergency Medicine 38: 170-176
Little R, Kirkman E, Driscoll P, Hanson J, Mackway-Jones K
1995 Preventable deaths after injury: why are traditional
Vital' signs poor indicators of blood loss? Journal of Accident
and Emergency Medicine 12: 1-14
Mellor A, Soni N 2001 Fat embolism. Anaesthesia 56: 145-154
Moore J, Moore E, Thompson J 1980 Abdominal injuries
associated with penetrating trauma in the lower chest.
American Journal of Surgery 140: 724-730
Nathan AT, Singer M 1999 The oxygen trail: tissue oxygenation.
British Medical Bulletin 55: 96-108
Nicholl JP 1999 Optimal use of resources for the treatment and
prevention of injuries. British Medical Bulletin 55: 713-725
Proctor J, Wright S 1995 Abdominal trauma: keys to rapid
treatment. In: Bosker G (ed). Catastrophic emergencies.
Diagnosis and management. American Health Consultants,
Atlanta, GA, pp 65-74
Skinner D, Driscoll P, Earlam R 1996 ABC of major trauma.
British Medical Journal, London
Slater MS, Mullins RJ 1998 Rhabdomyolysis and myoglobinuric
renal failure in trauma and surgical patients: a review.
Journal of the American College of Surgeons 186: 693-716
Tiwari A, Haq AI, Myint F, Hamilton G 2002 Acute
compartment syndromes. British Journal of Surgery
89: 397-412
Ware LB, Matthay MA 2000 The acute respiratory distress
syndrome. New England Journal of Medicine 342: 1334-1349
Wyatt J, Beard D, Gray A, Busuttil A, Robertson C 1995 The
time of death after trauma. BMJ 310: 1502
Useful links
www.doh.gov.uk/HPSSS Department of Health 2002
Indicators of the nation's health
46
SECTION 2
47
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3 Clin
ical diagnosis
/?. M. Kirk
Objectives
Clinical diagnostic skills are the basic
requirements for successful surgical
practice.
For success you need to know the range of
normality against which to measure
abnormalities.
Try to be positive in your opinions. Do not
hide behind vagueness.
repeatedly think, T wonder if this is condition X?' - a
hypothesis, followed by the intention to ask a further
question or carry out a specific test to see if the idea
survives it or is refuted - the deductive process.
Why do we not employ computers, into which
patients may enter information directly, for diagnosis?
Computers are often used to harvest preliminary infor-
mation as they can hold much more information than we
usually have easily accessible. But they are valuable only
when critically assessed information is entered. They are
mere repositories, hence the pithy American acronym
'GIGO' (garbage in, garbage out).
Should you read this chapter? Are you already too expe-
rienced to need further instruction? If you think so, you
are lacking in self-knowledge. None of us is completely
competent in the complex, and still not yet fully under-
stood, process by which we seek out a diagnosis of our
patients' clinical problems.
INTRODUCTION
^^^^v- 1 .^*;:.;^^
■^I^^^Mi^^^^^^^^m:^
Much has been spoken and written about clinical diag-
nosis. Although Sir Peter Medawar, the Nobel Prize-
winning immunologist, was not a clinician, he described
the process of making a diagnosis as similar to the process
of scientific research - hypothetico-deductive (Medawar
1969). A hypothesis (Greek hypo = under + thesis - a
placing) is a supposition or idea; deduction (Latin de =
from + ducere = to lead) is the application of critical testing
to the idea. The great scientific philosopher, Sir Karl
Popper, uses the parallel terms, 'conjectures (Latin con =
with + jacere - to throw) and refutations' (Latin refutare -
to drive back), suggesting that we should rigorously
attempt to destroy our hypotheses. If they withstand the
critical testing, we may accept them for practical pur-
poses. If we refute them, we are free to develop further,
perhaps more successful ideas (Popper 1959).
It has been said that an experienced clinician makes a
provisional diagnosis within a few seconds of seeing most
patients. Analyse your thought processes as you take a
history and examine patients. You will recognize that you
Key point
All facts are not of equal importance. Identify,
register and rely on the significant ones.
Computers lack intuition - the power of perceiving truth
without reasoning or analysis. As we communicate with
our patients, we take in, partly consciously and partly
unconsciously, details that weigh in the balance alongside
the words. A quiet response to the question, 'How severe
is the pain?' of, 'Chronic/ by a grey-faced London dock-
worker may signal greater suffering to you than the vehe-
ment retort of, 'Excruciating/ by someone with a more
volatile personality. Yet the first person may enter a score
of 6 out of 10 and the second 10 out of 10 in response to a
computer questionnaire in which 10 signals the highest
pain level. You have interpreted the Cockney slang word
'chronic/ (Greek chronos = time, hence longstanding), to
mean its opposite, 'acute'. Someone in excruciating pain
(Latin crucifigere crux = cross + figere = to fix, hence to
crucify; agonizing, anguished), often finds it difficult
forcefully to express their suffering.
HISTORY
J£C^&^'^^^i^& ^^O&^'-'&^^&^'^S
1 . We have traditionally prided ourselves as surgeons on
our ability to elicit physical signs and make accurate 'spot'
49
PATIENT ASSESSMENT
diagnoses. We have not always sufficiently developed our
communication and history- taking skills. An effective
history directs your attention to the cause of the surgical
problem. You can apply the famous statement of Louis
Pasteur about scientific discovery to the diagnosis of surgi-
cal disease / which may be translated as, 'Chance favours
the prepared mind/ The history directs you towards the
correct area of examination and investigation.
2. There are two, usually separate, parts of the history.
Initially you should concentrate on the presenting com-
plaint. Having clarified this, you need to investigate the
general physical and mental health of your patient and
identify coexisting or alternative disease.
3. Taking a history requires great tact. You must control
the direction it takes, otherwise you may be led away
from the line of pursuit of the diagnosis. When you ask a
question and hear the response, the timing and phrasing
of your next question is important. Too soon, too sharp, a
sudden change of topic, and you may prevent the patient
from adding a vital clue. Too late and the patient may
have led you on a false track.
4. As you take a history you are establishing a rela-
tionship with the patient. For this reason prefer to speak
together in a quiet, relaxed atmosphere. You cannot take
an accurate history unless you and the patient can com-
municate verbally. Make sure you understand the
meaning of the patient's statements - and the patient
understands yours. If you do not have a common lan-
guage, try to recruit an interpreter.
5. Ask 'open' questions whenever possible, for example,
'Where is your pain?' rather than Ts your pain here?'
6. Avoid appearing judgemental; patients often with-
hold information if you seem to disapprove. Equally, they
may give an incorrect answer, thinking that it may elicit
your approval.
Presenting complaint
1 . As you encounter each patient take in every detail of
gender, age, expression, speech, gait, dress and attitude.
This prejudices your interpretation of everything you
are told and subsequently find. Do not misinterpret
'prejudice'; it means prejudging; although it is usually
used disparagingly, it is reprehensible only if it is rigidly
maintained against the evidence. Treat your interpret-
ations as working hypotheses, to be tested and abandoned
if the evidence refutes it. By sensibly incorporating your
impressions of the patient with the history you are more
likely to reach a balanced judgement (Fig. 3.1).
2. Do you think that the complaint made by the patient
is the one that is the cause of anxiety? Sometimes patients
find a reason to see a doctor, worried about a condition,
yet are unable to express it, from diffidence, embarrass-
ment or fear of the consequences.
3. The next time you sit before a patient, try to follow
the sequence of your questions. What is your motivation
for asking each one? Each one should elicit a clue to the
diagnosis, clarify the answer to the previous question or
elicit fresh information.
4. If you can identify the exact site of the symptoms,
you may be able to identify the likely system. If so, ask
about the effect of system function on the symptoms and
the effect of symptoms on the system function. In this way
you can sometimes recognize a pattern of features that
form a syndrome (Greek syn = together + dromos = a
course; hence, a concurrence of features).
5. If you think you have identified the cause of the pre-
senting features, do not relax. While you are questioning
the patient the answers you receive should trigger other
possible diagnoses and you need to ask questions that
will substantiate or exclude them. Thus, you are running
several lines of thought in parallel.
6. Your targeted history is incomplete until you have
sought out evidence of the severity of the cause of symp-
toms, its extent and rate of progression.
General assessment
1. There are well-established questions to check the
function and health of the main body systems. Employ
them to identify or exclude coexisting problems. For
example, the answer to, 'Can you climb stairs?' may
reveal preliminary information about the function of the
• Young child
■ Young woman
• Young man
■ Middle-aged woman
• Middle-aged man
• Elderly woman
• Elderly man
Appendicitis
Gynaecological
Hernia, appendicitis
Gynaecological, dlvertitulosis coli
Diverticulosis coli or colon cancer
Gynaecological; cancer or diverticular disease of the colon
Colon cancer
Fig. 3.1 Your intuitive diagnosis for lower abdominal pain depends upon the patient before you. These are some
preliminary diagnoses - but do not consider them to be a final judgement.
50
CLINICAL DIAGNOSIS
3
Anatomical structures at site of lesion?
Skin, subcutaneous tissue, fascia, blood
vessels, lymphatics, nerves, tendons,
muscles, bones, joints, mesothelia, viscera, etc.
versus
Congenital
Traumatic
Inflammatory
Degenerative
Metabolic
Neoplastic
Fig. 3.2 Mentally test each of the likely tissues in the detected lesion against the pathological grid. You hope to
identify the combination that fits the information that you have acquired.
cardiorespiratory, haematological, musculoskeletal and
neuromuscular systems.
2. While taking the history, carefully assess the person-
ality and attitude of your patient. Try to identify any
anxieties or misapprehensions that need to be discussed.
EXAMINATION
^ J M&$%'M'&$.'i?&'?-
1. You cannot carry out a thorough examination in an
atmosphere of hysteria, noisy distraction or pressure of
time. Relax and reassure the patient, and also make an
effort to relax yourself.
2. When you took the history, you should have identi-
fied the important clinical signs you need to seek, but
seek to identify further ones as you proceed through the
examination.
3. Do not rush. Take each examination in turn and do
not proceed until you have decided confidently, Is the
sign present, or not?"
Key points
• You can confidently reassure your patient that
all is well only if you know the range of
normality.
* You learn the range of normality only by
assiduously building up your experience every
time you have the opportunity.
4. If you find a suspicious lesion, identify exactly
where it lies both 'geographically 7 and in depth, including
its attachments. You may then apply the anatomico-
pathological grid (Fig. 3.2).
5. If you find an enlarged lymph node, examine the
whole of its potential drainage area - and remember that
when lymphatics are blocked, the flow may become retro-
grade (Latin retro = backward + gressus = to go).
6. If you find an abnormality in one part of a system,
examine the whole system, such as the reticuloendothelial,
vascular, neurological, joint, bone, muscles, skin systems.
7. If you need to curtail the full examination in an
emergency, or in order to start treatment, determine to
complete it as soon as possible.
8. Even though you may be certain of the clinical signs,
be prepared to repeat the examination before you take
action. Especially in emergency circumstances, such as an
acute abdomen, physical signs often change rapidly.
9. Record your findings in full. If you do not record
negative findings it may be assumed you did not seek
them. Write legibly and do not use abbreviations or
jargon. Write the time and date, and then sign the record.
10. Your hope is that you will reach a likely clinical
diagnosis, excluding other possibilities so that you may
plan the investigations (Fig. 3.3).
Key points
The commonest condition is the most likely.
Remember, though, the 'pay-off' diagnosis - the
one that may be less common but has
important consequences if you miss it. (Warning
expressed by Hugh Dudley, formerly Professor of
Surgery, St Mary's Hospital, London.)
History
Examination
Investigations
Presenting
Feature
Condition A
Condition B
Condition C
Excluded
Confirmed
Possible
Excluded
Confirmed
Possible
Assess
Exclude
Fig. 3.3 As you proceed, you often accumulate further possible diagnoses. You run with all of them in parallel,
hoping to exclude some. Some you confirm but need to assess the extent of disease. Others you keep in mind, hoping
to confirm or exclude them by means of carefully chosen investigations (see Ch. 4).
51
PATIENT ASSESSMENT
11. Write a brief summary of the present situation:
what will be done, why, and with what intention. Anyone
reading the notes can now rapidly grasp the problem and
the intended management of the patient.
DIAGNOSIS
■&^%$V&9&^^
^&S$^W$^&sl$Z$i&$5g&
^&&^l&:s$Wi?&;gf&?&Q!t^£&& ; W!(;#
1- As you discover symptoms and signs, decide if they
are significant and reliable. Sometimes you find features
that are contradictory and must decide which ones, if any,
to trust.
2. Pattern recognition contributes powerfully to diag-
nosis. The almost subconscious recognition of a type of
patient, a particular symptom and the discovery of a sig-
nificant feature produce a pattern. Try asking yourself to
describe someone close to you; remarkably, you may not
be able to articulate many observations, yet you instantly
recognize the person in a crowd. Overreliance on pattern
recognition is dangerous. As you become experienced,
having become acquainted with a large number of syn-
dromes, you risk accepting them without further corro-
boration. Remember Karl Popper's admonition to test
your hypothetical diagnosis. The extra effort often dis-
closes a feature that throws doubt on the initially recog-
nized likely diagnosis.
3. Perhaps the most daunting declaration to your
patient is to state that there is no disease. This demands
confidence in your findings and your diagnosis. It is also
one of the most satisfying acts - at least comparable with
pulling off a dramatic life-saving action. If you can look the
patient in the eye and say, 'It is all right/ imagine the relief
and joy your declaration brings. In many cases you can
send the patient away, feeling relieved and happy, or order
carefully selected investigations to confirm your diagnosis.
4. Not every patient's clinical features correspond to
textbook descriptions. Be alert to the exceptions. Sometimes
an apparently capricious finding warns you that you are
misinterpreting the evidence; sometimes you are able to
discover a previously undiscovered feature.
Key point
If investigation results do not match your
clinical diagnosis, trust your clinical findings;
investigations are clinical aids.
Diagnosis not made
1. Do not rush to order more complex investigations.
One of the most productive methods is to put aside the
previous notes and start afresh. This is particularly so if
someone else previously saw the patient. A fresh person
taking a history asks questions in a different manner and
different order. The new history is often surprisingly
different from the original one.
2. Repeat the clinical examination. Do not automatic-
ally accept the findings of someone else, however senior
or distinguished.
Key points
• Did you ignore or dismiss information that
clashed with your preconceptions?
• Never fail to respond to changed circumstances
or 'uncomfortable' new information.
3. Did you order the correct investigations? Remember
that many investigations are operator dependent. If the
investigation does not confirm your clinical judgement,
consider repeating it after discussion with the person
carrying out the procedure, rather than ordering another
one that is perhaps more complex, expensive and po-
tentially dangerous.
4. It is not always necessary to make a diagnosis before
taking action. In an emergency you may need to act
without knowing the exact cause of cardiorespiratory
failure, calamitous bleeding or acute abdominal symptoms.
Summary
• Do you appreciate the immense and
crucial value of history taking?
• Do you recognize that to diagnose a lesion,
or confidently reassure your patients that
all is normal, you must be thoroughly
familiar with the range of normality?
• Will you remember that clinical diagnosis
is not an end in itself? It offers a valuable
opportunity to assess the character of the
patient and establish a relationship.
• Will you assiduously record what you asked,
what you were told, what you examined,
what you found, what it means and what
actions you have taken or will take?
References
Medawar PB 1969 Induction and intuition in scientific thought.
Methuen, London, pp 42-45
Popper K 1959 The logic of scientific discovery. Rou Hedge,
London
52
Investigations
A/. J. W. Cheshire, C. Bicknell
Objectives
Define the aims of investigation used in
surgical practice.
Understand the principles underlying
selection of appropriate investigations.
Determine the limitations of commonly
used investigations.
Consider appropriate sequences and
timing of multiple investigations.
Highlight important principles of
investigations most commonly used in
clinical practice.
INTRODUCTION
ment. The most common reasons for ordering investiga-
tions in surgical practice are outlined below.
Confirm the diagnosis
Use investigations to confirm a suspected clinical diag-
nosis, if clinical features are equivocal. Do not assume that
tests are essential to diagnose, however, as there remain
conditions for which clinical diagnostic acumen matches
or exceeds the accuracy of any investigative tool (acute
appendicitis), as well as conditions whose treatment
uncontroversially confirms the diagnosis (ischiorectal
abscess). Nonetheless, even in these instances confirma-
tion of the clinical diagnosis is useful, usually histologi-
cally, to avoid missing an underlying condition, such as
carcinoid as a cause of appendicitis or Crohn's disease
leading to ischiorectal abscess formation.
The use of investigations in surgical practice is no substi-
tute for clinical skill. An investigation is only worthwhile
when it is requested in order to answer a specific ques-
tion, or to confirm a clinical impression prior to interven-
tion. There is an ever-expanding range of investigative
modalities available and unwary surgeons who are clini-
cally uncertain can easily find themselves overwhelmed
with information if too many poorly considered investi-
gations are requested. Furthermore, many modern tests
are expensive and the costs of any investigation must
always be considered in today's financially conscious
health service. Other important issues that govern the
effective use of special investigations include their selec-
tion, timing and interpretation. This chapter outlines
some of the principles that should be applied before
investigations are requested in surgical practice, high-
lights the limitations and discusses the practical use of
common investigations.
AIMS
WS^V&Wt&^&riS^-'&'i/:
Investigations are performed for different reasons but all
should share the common feature of directing manage-
Key point
Remember that investigations are only
worthwhile when they direct management.
Exclude alternative diagnoses
Perform specific investigations in order to exclude an
important alternative or additional diagnosis (frequently
malignancy). Many examples of this practice exist. An older
patient with new per-rectal bleeding presenting to the colo-
rectal clinic may well have piles easily visible on examin-
ation, but must undergo further examination to exclude
colonic cancer. Remember resource and financial implica-
tions when planning investigations in this manner; in-
appropriate investigations need to be avoided in all the
surgical specialities, especially when pursuing ill-defined
abdominal pain (in general surgery), vague back pain (in
orthopaedic surgery), 'cystitis' in young women (in gynae-
cology and urology), chronic rhinitis (in ear, nose and throat
(ENT) surgery), ill-defined and longstanding headaches (in
neurosurgery). Never ignore these symptoms, but take a
53
PATIENT ASSESSMENT
full history and examination to form a clinical impression
of the likely cause and think carefully of the diagnoses that
cannot be missed or may occur concurrently. A combina-
tion of clinical and risk assessment for each individual
patient should guide the investigations performed.
B
Key point
Treat all patients on an individual basis when
considering tests to exclude alternative
diagnoses.
criminately investigating in the domain of another special-
ity. Consult the anaesthetist ahead of planned surgery to
reduce avoidable cancellations on the day of surgery.
Key point
• You cannot undertake a full and informed
discussion of the diagnosis, treatment options
and likely outcomes with the patient and
family prior to surgery until these necessary
investigations have been performed.
Confirm the need to intervene in the
absence of a diagnosis
In an emergency you may need to act after investigations
confirm a need for emergency treatment without
knowing the specific cause.
Determine the extent of disease and staging
It is considered best practice to map out the extent of the
disease before surgery especially in the elective setting. In
fact when treating patients with neoplasia, staging is
essential. Although the diagnosis of oesophageal cancer
has been made, it is necessary to map out the extent of the
disease, as the presence of an advanced rumour stage
negates the need for operation and the physician may
concentrate on palliative or chemotherapy treatment. You
should also determine the extent of disease to optimize
the use of operating theatre time and equipment, plan the
operation carefully, avoiding having to make hasty deci-
sions in the operating theatre, and minimize the chances
of the surgical team being presented with any unpleasant
surprises during the operation.
Evaluate comorbidity
Assess fitness for anaesthesia using a well thought out plan
of investigations. A patient with an asymptomatic aortic
aneurysm typically presents with a history of smoking and
widespread cardiovascular disease; he or she requires par-
ticularly careful evaluation of cardiac, pulmonary and renal
function if the risks of surgery are to be balanced against
the risk of conservative treatment, and informed advice
about mortality and outcome are to be given to the patient
when consenting for operation. While in many cases a com-
bination of the use of cardiac, renal and lung function tests
can appropriately assess fitness for anaesthesia, expensive
and time-consuming tests cannot be undertaken on all
patients. If the clinical history is not straightforward, seek
a cardiological or respiratory opinion instead of indis-
Risk to others
Consider all patients to be at high risk for blood-borne
infectious disease so that the risk of needlestick injury is
minimized. However, in some circumstances hepatitis B,
C and human immunodeficiency virus (HIV) serology
(with consent) may be appropriate in patients being pre-
pared for surgery in order to determine risk to others. In
all patients the methicillin-resistant Staphylococcus aureus
(MRSA) status should be determined and appropriate
isolation procedures activated where necessary. This is
particularly true of patients who have been transferred
from another hospital and those with leg ulcers, who may
have colonization of the wound site with MRSA.
Medicolegal considerations
Although you may be certain in your own mind about the
diagnosis and appropriate management, you may need to
protect yourself against future claims of incompetence
against you, or the patient may wish to have objective evi-
dence available in claims against a third party following,
most commonly, an accident. When in doubt take advice
from a senior colleague or from a medicolegal expert.
SELECTION
i^^isss»aa«w*s»ss»^^
&s+¥-;*«fe:^iViM:-s^^
There is often more than one modality that may be used
to answer the clinical question the surgeon is faced with,
in which case you need to consider the selection of the
most appropriate investigation, which varies on an indi-
vidual basis. Various factors influence this choice.
Sensitivity and specificity
If one test is known to be more sensitive than the alter-
native, this is obviously a good reason to choose it.
Colonoscopy is more sensitive than barium enema for the
detection of small polyps and is the investigation of
54
INVESTIGATIONS
W 4
choice with lower gastrointestinal tract bleeding. The
investigation must be specific for the disease when alter-
nate diagnoses are to be excluded. 123 I scintigraphy for
investigation of thyroid nodules is hard to justify as only
10% of low-uptake nodules are subsequently shown to be
malignant. Sometimes the combination of tests can raise
the sensitivity and specificity to the acceptable standards,
such as triple assessment of a breast mass, which com-
bines radiological, cytological and clinical assessment to
improve the sensitivity and specificity of the assessment.
Definitions
Sensitivity: number of cases of the condition
detected by the test/total number of cases in
population studied.
Specificity: number of truly negative results/total
number of negative results.
Simplicity
A simple investigation may be the first line of investiga-
tion and may be all that is needed. If a plain radiograph
confirms the clinical diagnosis of osteomyelitis in a dia-
betic foot and the management plan is clear, it is not
necessary to order a bone scan or magnetic resonance
imaging (MRI). Free air seen on an erect chest X-ray
confirms the diagnosis of bowel perforation and no
further investigation is necessary. A simple investigation
that proves to be undiagnostic, however, will require
more detailed studies to be performed.
Safety
Think carefully about the complications of an investigation.
Endoscopy may provide useful information as to the cause
of bowel perforation but it is not safe in this situation, nor
is the use of barium-based contrast. While a Tru-cut biopsy
may confirm a diagnosis, it may also result in tumour
seeding - ask the cyto/histopathologist whether a fine
needle aspirate (FNA) may give sufficient information for
management decisions to be made. For example, parotid
tumours are at high risk from wound tumour seeding if
investigated in this way and histological confirmation of
the diagnosis often must wait until the mass is resected.
Cost
If an ultrasound can show liver metastases and this is the
only information you require to decide on appropriate
management, then why order a computed tomography
(CT) scan that may be up to ten times more expensive?
Remember that resources are limited. Reassurance and cer-
tainty are purchased at a price. Moving from a position of
95% to 100% certainty is often very expensive. When using
investigations it is vital to understand the need to manage
risk while at the same time remaining accountable to the
patient and to society for the way in which money is spent.
Acceptability
In general the less invasive the investigation the more
acceptable it is to the patient. This is especially true in
paediatric practice, where the acceptability of the investi-
gation to the child is essential if meaningful results are to
be gained from investigations. Consider carefully the
acceptability of the test when patients are being screened
for asymptomatic disease. One of the limitations of the
use of faecal occult blood testing as a screening investi-
gation for colorectal cancer has been the relative unaccept-
ability of this investigation to patients. Unacceptable tests
suffer from poor compliance and a screening programme
may achieve poor results in this situation.
Availability
The gold standard may be the ideal choice of investiga-
tion for a patient but may not be possible. For example,
an MRI scan may provide more information about the
brain after injury or prior to neurovascular or neurosur-
gical intervention, but if the institution you are working
in does not have an MR scanner and you need informa-
tion rapidly you must make do with a CT scan.
Routine
Surgical departments may have their own series of inves-
tigations set out within a protocol. You should discuss
with your consultant and the anaesthetic staff the circum-
stances in which investigations that do not conform to the
categories outlined under 'Aims' should be performed.
LIMITATIONS
^&!S$^«i3ai^iS!**Mi^^
Remember that all investigations have limitations that
need to be considered when ordering tests and interpret-
ing results.
Incorrect result
Do not discard your clinical impression, if the result of
any investigation conflicts with your clinical judgement,
without considering the possibility that the test may
be misleading. Check that the correct procedure was
performed and the procedure was performed correctly.
55
PATIENT ASSESSMENT
Take into account any problems encountered with the
procedure when interpreting results.
Gaining sufficient confidence in your clinical ability to
question the opinion of others is difficult but also essen-
tial if a safe and rewarding clinical practice is to be devel-
oped. Remember that in many circumstances you, as the
surgeon, may be the only individual who has actually
spoken to and examined the patient and therefore you are
in a unique position to judge the likely accuracy of the
investigation result you are presented with.
Key point
Do not blindly read a test result without
considering the clinical picture.
The investigation may also be misleading as a result of
the limited sensitivity of an investigation. For example, a
technically adequate breast fine needle aspiration may
have been taken and correctly interpreted but may miss a
carcinoma because of a sampling error of the lump
assessed. Remember also that an investigation may yield
a false-positive as well as false-negative result.
Consider repeating or choosing another test to answer
the same question if an investigation does not support a
firm clinical diagnosis. Discuss the test with the person who
performed it to ensure that as much clinical information as
possible has been passed on to the individual who is trying
to give you a result. An inadequate report may have been
based on inadequate information given on the request
form. Combined clinical meetings between the surgical
team and specialized radiologists, histopathologists, etc.
are often the ideal forum for the presentation of clinical
information and review of investigations. In this situation
interpretation of radiological images or histological diag-
noses may be revised and fit with your clinical impression.
If a test is thought to be misleading it is often useful to
repeat it, consulting the most clinically reliable investigator.
Key points
• Many investigations are operator dependent -
subjective opinions, not objective proofs.
• If an investigation does not conform with your
firm clinical impression, first discuss it with the
investigator before embarking on more
complex tests, and consider repeating the test.
Complications
An investigation may be associated with a significant
complication rate, an issue that may not only influence
one's choice of its use, but also may have medicolegal
implications if it has not been discussed at the time of
consent. Is a selective carotid arteriogram really worth the
1% stroke rate when a duplex scan may give all the
necessary information? Think whether this complication
rate could be reduced or should be avoided altogether.
Hydrate the patient intravenously and consider pretreat-
ment with N-acetylcysteine in a patient with a raised
creatinine before giving contrast to perform CT or an
angiogram. Give the older patient Klean-Prep rather than
Picolax before a colonoscopy.
SEQUENCE AND TIMING OF
IN^STIG|mONS_
Organization
Do not collect data indiscriminately when you are inves-
tigating a patient prior to surgery or during follow-up.
Always organize the flow of information you require so
that it follows a logical sequence that will culminate in
you being able to discuss the patient's condition and man-
agement, with any attendant risks, in a fully informed
manner and from a position of strength. During the pre-
operative process of diagnostic confirmation, determina-
tion of the extent of disease and exclusion of specific
alternative diagnoses, you will frequently need more than
one special investigation. In these circumstances thought
must be given to determining the appropriate order of
such investigations. Avoid the temptation to arrange all
investigations at one sitting to prevent the patient having
to come back repeatedly to the clinic. It is obviously inap-
propriate to arrange cardiology and pulmonary function
tests to assess fitness for surgery at the same time as deter-
mining the primary disease and any spread. If the surgi-
cal problem turns out to be inoperable, then the other
investigations undertaken have usually been a waste of
time and resources as well as putting the patient at poten-
tial risk. Patients often understand the need for a logical
sequence of investigations and the time this may require.
Urgency
Consider the urgency of each individual investigation
and request appropriately. For the patient with a poten-
tially curable carcinoma, investigations must be carried
out quickly and efficiently. Conversely, there is no sense
in flooding the radiology department with urgent
requests that are to determine the cause of problems that
have dragged on for many years.
The purpose of investigations is to reduce the manage-
ment options and to seek to obtain crucial information
once, not repeatedly. Sometimes an impasse is reached.
56
INVESTIGATIONS
W 4
Reflect, reconsider and perhaps postpone a decision for a
while, using time as a diagnostic tool. If you rush to make
a decision where there is no indication for urgency you
will make mistakes. A high negative laparotomy rate in a
surgeon usually indicates an unwillingness to use time in
this way, perhaps because of organizational constraints.
Avoid the temptation to do a laparotomy in the middle of
the night just because of the difficulties you might
encounter if the need for surgery emerges the next day.
Protocols
Often the sequence and choice of investigations is pre-
sented in the form of protocols, where guidelines are set
out enabling all staff to follow the preferred investigative
methods of a department. These are useful in common
conditions, both as a diagnostic tool (such as the investi-
gation of rectal bleeding) and as a preoperative work-up
regimen (in the case of complex surgical procedures, such
as complex aneurysm surgery or cardiac surgery, where a
number of preoperative investigations must be per-
formed). A well-written protocol allows the surgeon who
is unfamiliar with the working practices of the hospital to
be able to investigate a particular condition appropriately.
They may also form guidelines for specialist nurses or
nurse consultants to work from, making services more effi-
cient and decreasing waiting times. Protocols are invalu-
able in the procedure of audit as all staff must work to a
standard, which they are expected to maintain. They also
prevent unnecessary and costly investigations being per-
formed. A rigid protocol has a number of advantages but
you must remember that they are no substitute for clinical
acumen and all cases must be dealt with on an individual
basis, with investigations directed to a particular patient.
PRACTICAL USE
Blood tests
Most laboratories use automated analysers that give all
the common haematological and biochemical indices. You
only need ask for a full blood count to receive a full set of
haematological parameters. Interpret the results in the
light of the patient's general condition. For example,
dehydrated patients have a high haemoglobin and
packed cell volume (PCV, haernatocrit) because of haemo-
concentration; a normal haemoglobin in such patients
may mask anaemia.
Levels of substances may be affected by the timing of
blood sampling. The creatinine kinase is only transiently
raised in the plasma after myocardial infarction; other
enzymes are increased later. There is a diurnal rhythm
with hormones such as Cortisol that may produce
misleading results. Binding proteins and plasma proteins
affect hormone, enzyme and drug levels, so allow for this
when interpreting results.
Remember the biochemical picture is obtained from just
a sample of plasma. You are only indirectly discovering
what is going on inside cells. Potassium levels, for
instance, reflect poorly the intracellular potassium. In dia-
betic ketoacidosis the plasma potassium level is high but
the patient is intracellularly depleted of potassium as
insulin levels are low and potassium is not taken into cells.
Discuss unusual cases with an expert. Examination of
a blood film by an experienced haematologist can prove
diagnostic in the case of a raised white cell count (WCC)
where the cause is in doubt. Further investigation of the
patient may also be influenced by an opinion from an
expert. It may be that if the peripheral blood picture
shows involvement (as in chronic lymphatic leukaemia),
peripheral blood marker studies will lessen the need for
lymph node biopsy. This will avoid the need for a general
anaesthetic, and a bone marrow sample can be taken
under local anaesthetic instead.
Microbiology (see also Ch. 19)
A pus swab only briefly contains a representative sample of
organisms from an infected source. Organisms die because
they are anaerobic (e.g. Baderoides), because they are deli-
cate (e.g. Neisseria) or because the other organisms in the
sample proliferate faster and overwhelm them. Therefore
lose no time between taking the swab and transferring it to
an appropriate medium for culture. If pus is available,
collect a quantity and send that, rather than a swab, to the
microbiologist. Store pus swabs (in appropriate transport
medium) at 4°C when taken at night and ensure that they
are sent to the laboratory the next day. Remember that prior
consultation with a microbiologist may increase the yield of
relevant positive cultures obtained.
Taking many swabs for culture without clinically
assessing the patient or careful thought may cause you to
miss the diagnosis. Make sure you ask the correct ques-
tion in order to select the best method of answering it. The
detection of amoebic dysentery is not accomplished by
taking a swab for culture but by examining a fresh speci-
men immediately under the microscope. The positive
identification of bacteria responsible for late vascular
graft infections often requires special techniques (e.g.
sonification) to separate the bacteria prior to culture and
this requires all the clinical information to be passed on
to the microbiologist before the arrival of the specimen.
Inform the laboratory of all relevant clinical informa-
tion and antibiotic treatment so that the microbiologist
can read the results sensibly. For instance Gram-positive
cocci within a blood culture may indicate a skin contami-
nant, such as Staph, epidermidis, or an MRSA septicaemia.
57
4
PATIENT ASSESSMENT
In the patient with no sign of sepsis, it is sensible to wait
for the full report from the bacteriologist.
Always seek the help of the microbiologist whenever
you deal with superadded infection, especially in trans-
plant patients and in the immunocompromised (as in HIV
infections or in patients on chemotherapy). Pneumocystis
carinii is the commonest opportunistic infection here. The
picture can, however, become quite complicated, partly
because several infective agents can become involved
(bacterial, viral or fungal) and partly because the picture
may change from day to day.
Radiological investigations (see also Ch. 5)
X-ray examinations are one of the simplest and cheapest
radiological investigations to perform. Use these as a first-
line investigation in cases of suspected perforation and
obstruction before more expensive and complicated tests.
Think whether introduction of a contrast agent into a
cavity or lumen would improve the diagnostic accuracy
of the test if initial plain films are inconclusive. For most
patients the radiation experienced from X-rays will not
cause problems but the dose is cumulative, so when poss-
ible avoid repeated tests that use radiation, especially in
the case of long-term screening.
Histopathology
A biopsy is a representative sample of tissue that may
be examined by a histopathologist. The tissue may be
obtained in a variety of ways and biopsies are classified
according to how they are obtained. Excision biopsies
remove the entire lesion and undoubtedly provide the
best tissue for histopathological examination. Wedge
biopsies provide a section of tissue from a lesion, while a
core biopsy is performed with a Tru-cut biopsy needle to
take a small core of the lesion. Discuss with an expert the
best type of biopsy to get an accurate answer and consider
radiological methods of obtaining tissue to avoid open
biopsy and obtain an accurate sample. Be careful when
taking a biopsy to include a representative sample of the
lesion. From the histologist you want to know what the
lesion is, whether the lesion is malignant and the prog-
nostic indicators. When taking a biopsy, therefore, be
careful to take tissue and not only the necrotic centre;
when obtaining samples from polyps sample the stalk, so
that you may find out the degree of invasion; and when
sending resected specimens orientate them appropriately.
Talk to the pathologist, relay important clinical informa-
tion and find out about resection margins, the grade and
stage of disease.
Fine needle aspiration does not give the same architec-
tural detail as histology but it is quick, relatively painless,
requires no anaesthetic, the complications of biopsy are
avoided and it can provide cells from the entire lesion, as
many passes through the lesion can be made while aspir-
ating. For all cytological examinations there are errors that
may occur in the sampling stage, where the lesion may be
missed or an inadequate sample taken, or in the patholog-
ical examination. You need to know from the cytologist
whether the sample was adequate and whether normal or
malignant cells were seen. If the sample is inadequate the
test will usually need repeating. Cytological specimens can
also be obtained from spun down samples of fluid from a
patient. Urine, pleural aspirate and sputum can all be
examined for malignant cells. Think of these simple ways
of obtaining cytological evidence of malignancy.
Invasive diagnostic procedures
The use of endoscopy provides a direct method of visu-
alization of pathology and also allows biopsy or definitive
treatment of lesions. A negative endoscopy is usually
more reliable than a negative contrast study, but remem-
ber that it is operator dependent and that subtle lesions
may have been missed (ask about the seniority and expe-
rience of the operator if you did not perform the investi-
gation yourself). It may need repeating in cases of doubt.
Diagnostic laparotomy, and more commonly laparos-
cope is used as a diagnostic tool in specific circumstances
such as preoperative staging of certain cancers. The need for
diagnostic procedures of this kind has fallen with the
advent of high-resolution scans such as CT and MR.
Physiological assessment
Use this type of assessment when you require information
on the physiological workings of an organ or part of an
organ. Motility disorders may be investigated effectively
by oesophageal or rectal manometry, which will supple-
ment anatomical and pathological information that has
been gained. Manometry will quantify the problem, as
well as facilitate the selection of operative therapy.
Summary
• Do you understand the purpose of each
investigation ordered in common
conditions?
• How do you decide which investigation is
the most appropriate?
• Can you name investigations with a
limited reliability?
• Which tests have serious complications?
• Can you formulate sensible investigation
plans for complex diagnostic problems?
58
Imaging techniques
5. 1/1/. T. Gould, T. Agarwal, T. J. Beale
Objectives
• Become familiar with the basic techniques
and principles of radiological investigation.
• Be able to enumerate the different types
of radiological modalities, together with
their advantages and limitations.
• Understand the principles of selection of
the most appropriate radiological
technique for a given clinical problem.
• Identify the key roles of radiology in the
diagnosis and management of surgical
disorders.
Key point
* Remember the maxim, 'treat the patient and
not the X-ray'.
TYPES OF RADIOLOGICAL
INVESTIGATION
S««.*essii#iSsS»
ai«&»we?s;!5s»*:«.S
The wide range of imaging techniques available includes
plain film radiographs (X-rays), fluoroscopic screening,
ultrasound, computed tomography (CT), magnetic reson-
ance imaging (MRI) and nuclear medicine. Each of these
will be described briefly.
INTRODUCTION
t^K^^.^^^SSW!^:^!
^•^■^■^^^^s^iV
&fg$%&^Stt^&}i&}l$^^*tt
Radiology is one of the most rapidly expanding special-
ties. This is due to continuing advances in both computer
and machine technology. New imaging techniques, dra-
matically affecting patient assessment, are constantly
being introduced. It is thus becoming increasingly diffi-
cult for surgeons to keep up to date with them. There
must therefore be close communication between surgeons
and radiologists to ensure that the most appropriate
imaging technique is utilized for specific surgical prob-
lems. This is best achieved by regular interdepartmental
meetings and individual case discussions of the more
problematic patients.
The correct imaging technique can be chosen only if
you make all the facts available to the radiologist. To this
end, include the appropriate clinical details on the
imaging request form.
Bear in mind the high cost and limited availability of
some of the more sophisticated imaging techniques when
deciding on the radiological investigation. Do not forget
that the required information can often be obtained from
plain X-rays and simple contrast studies.
No radiological technique replaces clinical skills. Do
not base clinical decision making on imaging findings
alone.
Plain radiographs (X-rays)
1 . X-rays were first demonstrated by the German physi-
cist W. K. Roentgen, in 1895. He discovered, fortuitously,
that X-rays not only expose photographic plates, they are
also absorbed to varying degrees by intervening structures,
which are then projected onto the photographic plate as
negative images. The clinical relevance of this discovery
was immediately apparent as, for the first time, imaging of
the living skeleton was possible, enabling deformities, frac-
tures and dislocations to be seen. To this day the indica-
tions for plain radiology have not changed, although X-ray
imaging has now been used in every other system of the
body. This has come about mainly due to the use of con-
trast agents. Plain radiographs are used to demonstrate
contrast between tissues of different densities and, as such,
obviously show the skeletal system well. However, they
also demonstrate differences between gas and fluid and are
therefore the most sensitive imaging technique for the
detection of free intraperitoneal air after gastrointestinal
perforation. The use of radio-opaque contrast agents
increases the diagnostic yield of plain radiography. For
example, iodine-containing agents are excreted rapidly by
the renal route and so clearly outline the kidneys, ureters
and bladder. The same agents also delineate the internal
characteristics of blood vessels in angiography.
59
PATIENT ASSESSMENT
2. Plain radiography is the most frequently requested
examination. It is relatively cheap and simple to perform.
These images can, however, be difficult to interpret, par-
ticularly soft tissue images, and of course ionizing radi-
ation can be hazardous to health and to the developing
fetus. The actual radiation dose to the patient varies
greatly and depends on the density of the tissue through
which the X-ray beam must pass. The greater the density
of tissue, the more X-rays are absorbed in the patient and
fewer reach the film. Table 5.1 shows the relative dose of
common surgical requests compared to the radiation dose
of a chest X-ray. The radiation dose of a chest X-ray is
equivalent to 3 days of natural background radiation.
Ultrasound
1 . Ultrasound waves are created in a transducer (Latin
trans = across + ducere = to lead; a device that transfers
power from one system to another) by applying a momen-
tary electric field to a piezoelectric crystal which vibrates
like a cymbal, producing sound waves. The transmitted
waves interact with soft tissue interfaces and are reflected
back, deflected or absorbed. The sound waves that are
reflected are alone used to make the image. The greater the
difference in density between two adjacent tissue planes,
the greater the amount of reflected sound waves. For
example when the sound waves reach a solid gallstone,
most of it is reflected back, resulting in a bright collection
of echoes and an acoustic 'shadow' beyond the stone.
Ultrasound waves, however, are transmitted through the
surrounding biliary fluid, which appears black.
2. Ultrasound examinations are useful for visualizing
soft tissues. They easily demonstrate fluid collections in
the subcutaneous tissues, such as breast cysts, and within
the body cavities, as in the chest and abdomen.
Ultrasound has become the first line of investigation in
many conditions, such as gallstone disease. Its use is
limited by structures that obscure the passage of the ultra-
Table 5.1 Relative dose of
requests
common surgical
Radiograph
Equivalent number of
chest X-rays (approx.)
Chest PA
1
Abdomen AP
50
Pelvis AP
35
Lumbar spine AP and Lat
65
Barium meal
150
Sarium enema
250
IVU
125
CT head
115
CT chest or abdomen
400
sound waves, so it cannot give images of, for example, the
brain. Large amounts of bowel gas may prevent adequate
examination of the abdominal cavity, and the retroperi-
toneum is often poorly visualized. It is highly operator
dependent. It does, however, give dynamic, real time
images and is safe to use in any patient, including those
who are pregnant. It is relatively cheap and is mobile. It
is also useful for guiding diagnostic procedures such as
aspiration cytology or needle biopsy (see below).
3. Intracavitary ultrasound has been used for
transvaginal assessment of the pelvic organs in females
and transrectal evaluation of the prostate gland. More
recently endoscopic ultrasound (EUS) has been devel-
oped, combining the benefits of high frequency ultra-
sound and endoscopy A small ultrasonic transducer is
incorporated into the tip of an endoscope. It is particu-
larly useful in assessing the extent and especially the 'T'
(tumour) staging of oesophageal, gastric, pancreatic and
pulmonary rumours.
4. Focused abdominal sonography in trauma (FAST) is
gaining wide acceptance for assessing the abdomen in
haemodynamically stable patients suspected of having
abdominal injuries.
Fluoroscopic imaging
Many common requests to the radiology department
involve the use of X-ray screening. These include all barium
examinations, most interventional procedures (except those
under ultrasound, CT or MRI guidance) and sinograms,
cholangiograms, nephrostograms, etc. Each screening room
has an image intensifier that converts the X-ray image into
a light image, then to an electron image and finally back to
a light image of increased brightness. Fluorescence (hence
the term fluoroscopy) is the ability of crystals of certain
organic salts (called phosphors) to emit light when excited
by X-rays. This process is used both in film cassettes for
plain radiographs and in an image intensifier.
Barium salts are used to delineate the mucosa of the
gastrointestinal tract and are also used in dynamic studies
to help define the function of this system (e.g. in barium
swallow examinations). Gastrografin is a thin, water
soluble contrast medium which has the added advantage
of not being a peritoneal irritant like barium. It is used for
the evaluation of intestinal obstruction (both small bowel
and colonic) and for confirming the presence of a sus-
pected anastomotic leak.
Computed tomography (CT)
1. Some of the major advances in radiology in recent
years have been in the field of cross-sectional imaging.
Computed tomography (Greek tomos = slice + graphein -
to write: abbreviated to CT) and magnetic resonance
60
IMAGING TECHNIQUES
. 5
imaging (MRI) have revolutionized the investigation of
the central nervous system and other soft tissues.
2. The CT image is derived from computer integration
of multiple exposures as an X-ray tube travels in a circle
around a patient. The circular track is called the gantry. A
fan-shaped beam is produced by the X-ray tube(s) and is
picked up by a row of sensitive detectors aligned directly
opposite. The computer constructs the image by dividing
the gantry into a grid. Each box in the grid is called a voxel
and has a length, width and depth - slice thickness. Each
voxel is given a value representing the average density of
the tissue in the box; the value is measured in Hounsfield
units (HU) after Sir Godfrey Hounsfield who invented the
CT scanner in 1972. Water has an HU of 0, air -1000, fat
-80 to 100, abdominal organs 30-80 and compact bone
>250. Each voxel is assigned a shade of grey according to
its HU. The window level (WL) is the HU number in the
middle of the grey scale; the window width (WW) is
the range of HUs over which the grey scale is spread. Both
the WL and the WW can be adjusted to emphasize differ-
ences in soft tissue / lung or bony detail on the stored data.
These figures are always seen on the printed film.
3. Modern three-dimensional spiral CT scanners have
not only drastically cut down the time taken for the
imaging but multiplanar reconstruction is now possible.
This is particularly useful for the head, neck and face but
has found important applications in general surgical con-
ditions, a prime example being CT pneumocolon.
Magnetic resonance imaging (MRI)
1. Each body proton can be thought of as a very small
magnet. When the body is placed in a magnetic field,
these protons line up along the direction of that field. The
images in MR are generated by the energy released from
the protons when they realign within the magnetic field
after the application of radiofrequency energy pulses.
This electromagnetic energy is received by a 'coil' and
converted to images by a computer. Scanning methods in
MR are referred to as "pulse sequences' and the images
generated are often classified as Tl -weighted or T2-
weighted. In simple terms, in a Tl -weighted image, fat
appears as a bright signal and water appears dark, and in
a T2-weighted image, water appears as the brightest
signal with fat appearing dark. There is therefore much
scope for image manipulation by employing different
pulse sequences during a single examination.
2. MR images give unparalleled soft tissue resolution
but are generally less useful than other imaging methods
for bony structures. MR has inherent advantages over CT
and other imaging techniques, the most important being
the lack of ionizing radiation. It has multiplanar capa-
bilities, allowing imaging in any arbitrary plane, not just
the orthogonal planes (the standard projections) permitted
by CT It has great sensitivity to flow phenomena and
unique sensitivity for temperature changes.
3. Its disadvantages include expense and availability. It
is safe in the majority of patients but those with implanted
magnetic devices or metallic objects, such as certain
intracranial aneurysm clips, indwelling pacemakers,
cochlear implants or metallic intraocular foreign bodies,
cannot be safely scanned. Most orthopaedic implants,
however, are safe. Due to the physical constraints of the
machine, obese or claustrophobic patients may be unsuit-
able for imaging by this technique.
Nuclear medicine
1. A radionuclide is administered into the body and
subsequently undergoes radioactive decay. The common-
est radionuclide used in medicine is technetium-99m
( 99m Tc). The 'm' is placed after the mass number to indi-
cate a metastable state, i.e. an intermediate species with a
measurable half -life. " m Tc has a half-life of 6 h and is a
pure gamma emitter. This results in a relatively low dose
of ionizing radiation being delivered to the patient. The
radionuclide is labelled so that it can be targeted to the
tissue that needs to be imaged. For example, it may be
labelled by attaching it to red or white blood cells or a
variety of chelates. In the decay process gamma rays are
given off. These are detected by a gamma scintillation
camera and from them the images are formed.
2. The latest addition to the armamentarium is PET
(positron emission tomography), which has been useful
in the staging of various gastrointestinal malignancies. It
is particularly useful in preoperative assessment of nodal
involvement and detection of recurrence and metastases.
It is reserved for the assessment of equivocal cases, not as
a first choice procedure.
3. Tomographic techniques, commonly used in X-ray
and CT, have also been developed in nuclear medicine.
Tomography refers to the technique of 'cutting' the body
into the required imaging planes. An example is SPECT
(single photon emission computed tomography) and
involves gamma camera(s) rotating around a gantry, as in
X-ray CT. A volume of data can then be collected and
transaxial images reconstructed.
HOW ARE RADIOLOGICAL
TECHNIQUES USED IN SURGERY?
Radiological techniques are used in the management of
surgical diseases in one of three main ways:
1. To aid in the diagnosis of a surgical disorder
2. As an interventional technique to treat a surgical
disorder or one of its complications
3. To guide a surgical procedure.
61
PATIENT ASSESSMENT
Each of these main areas will be considered in turn, with
a few specific examples.
Aid to diagnosis
1. This is of course the simplest and best known appli-
cation. Examples include the use of an erect chest X-ray
to detect free intraperitoneal gas, and CT scan of the brain
to detect intracranial bleeding following trauma.
2. Radiology is a valuable screening aid, as in popula-
tion screening such as mammography, and also as part
of protocol-based preoperative imaging such as a chest
X-ray when preparing patients for major surgery. Always
prefer the simple, hence cheaper, investigation before the
complex, hence costlier, one if the simpler investigation
has a good chance of providing the diagnosis.
3. If possible, avoid those with a significant associated
complication rate or inherent danger; for example, in
pregnant women ultrasound techniques are safer than
those using X-rays.
4. All investigations, no matter how complex or invasive,
have a given sensitivity and specificity and therefore there
will always be a false-negative and a false-positive rate.
Key point
Prefer safer, and non-invasive tests, to
potentially dangerous and invasive ones.
Interventional techniques
1. Interventional radiology has developed into a special-
ity in its own right. There can be very few radiology depart-
ments that do not perform at least some interventional
techniques. Interventional radiology may be defined as the
performance of a procedure on some part of the anatomy
while using a radiological modality to guide that proce-
dure. Perhaps the simplest example is image-guided
biopsy. This is commonly performed using ultrasound or
CT guidance, although it is now possible to perform biop-
sies using the added advantage of MRI. In places this has
replaced the need for an open surgical biopsy. A good
example is stereotactic (Greek stereos = solid + tassein = to
arrange; location within three dimensions) core biopsy of
the breast, guided by digital mammography. The placement
of drainage catheters using ultrasound or CT has revolu-
tionized the management of postoperative complications
such as subphrenic abscess. Vascular surgery has been com-
pletely changed by the advent of interventional radiology.
The techniques include angioplasty, catheter thrombolysis
and stenting of aneurysmal or occlusive diseases, and novel
techniques that replace the need for high-risk surgery, for
example transjugular portosystemic shunting in portal
hypertension.
2. This is a field that is likely to improve further, given
the rapid development and integration of computer tech-
nology into imaging methods and the availability of new
imaging systems, such as interventional MRI, and tissue
destruction techniques, such as focused ultrasound and
radiofrequency ablation systems.
Image-guided surgery
1. Image-guided surgery is the use of a radiological
modality during a surgical procedure to give more infor-
mation than is available by direct inspection of the surgi-
cal field. The information so gained is used to influence
or guide the performance of the operation. There are
many examples in everyday surgical practice (Table 5.2).
The best known are fracture manipulation using image
intensification, and intraoperative cholangiography
during cholecystectomy to determine the presence or
absence of gallstones within the main bile ducts.
2. More advanced techniques include stereotactic
CT-guided neurosurgery and the use of intraoperative
ultrasound in hepatic and pancreatic surgery, to deter-
mine resectability and to determine the anatomical
location of vital structures as resection proceeds. This
technique may be used in both open and laparoscopic
procedures. It has recently become possible to perform
surgical operations within interventional MRI units,
harnessing the soft tissue and image manipulation power
of MR to guide the procedure. There have been recent
reports demonstrating the use of intraoperative MR to
guide complete tumour resection in the brain (Moriarty et
al 1996), breast (Gould et al 1998), and soft tissues (Gould
et al 2001). It has been shown to be a useful guide when
Table 5.2 Examples of image-guided surgery
Modality
Procedure
X-ray
Fracture reduction
X-ray
Removal of foreign bodies
X-ray
Intraoperative cholangiography
X-ray
ERCP
X-ray
Retrograde ureterography
X-ray
Intraoperative arteriography
Ultrasound
Laparoscopic staging of pancreatic
cancer
Ultrasound
Hepatic resection
Ultrasound
Complex anal fistula surgery
CT
Stereotactic neurosurgery
MR!
Neurosurgery
MRI
Breast surgery
62
IMAGING TECHNIQUES
f 5
operating on complex anal fistulae (Gould et al 2002). MR-
guided interstitial laser thermotherapy is being carried
out for ablation of irresectable and metastatic tumours. It
has the added advantage of intraprocedural monitoring
and can be performed under local anaesthesia. Some sur-
vival benefit has already been described for this technique
for ablation of colorectal metastases in the liver.
3. Finally, radiological data obtained preoperatively
can be used to plan or guide surgical procedures. The best
examples are three-dimensional CT reconstructions of the
face or skull for surgical planning prior to major maxillo-
facial reconstructive surgery. This technique is now used
to plan the best approach for major hepatic surgery for
trauma or tumours. An extremely exciting area of current
investigation is the combination of information obtained
from a number of radiological techniques, such as CT, and
conventional and functional MRI to make a comprehen-
sive three-dimensional preoperative model of lesions and
surrounding anatomical structures. Work is underway to
'register' this image to the patient during surgery, so that
it may truly be used as an intraoperative guide.
Summary
• Do you appreciate the wide variety of
radiological imaging methods that are
currently available?
• Are you aware of the value of consulting
your radiologist in order to select the most
relevant investigation?
• Do you recognize that selecting an
appropriate investigation demands
balancing the aim of the investigation,
effectiveness, cost and safety?
Are you aware that radiological images
should not be used in isolation but must
be used in conjunction with the rest of the
available clinical information?
Do you recognize the three key areas of
diagnostic radiology, interventional
radiology and image guidance of surgical
procedures?
Can you foresee the likely future
applications of interventional radiology
and image-guided surgery?
References
Gould S, Lamb G, Lomax D, Gedroyc W, Darzi A 1998
Interventional MR-guided excisional biopsy of breast lesions.
Journal of Magnetic Resonance Imaging 8: 26-30
Gould SWT, Agarwal T, Benoist S, Patel B, Gedroyc W, Darzi A
2001 Resection of soft tissue sarcomas with intraoperative
magnetic resonance guidance. Journal of Magnetic Resonance
Imaging 15(1): 114-119.
Gould SWT, Agarwal T, Martin S, Gedroyc W, Darzi A 2002
Image guided surgery for anal fistula in a 0.5T interventional
MRI unit. Journal of Magnetic Resonance Imaging 16: 267-276
Moriarty T, Kikinis R, Jolesz F, Alexander III E 1996 Magnetic
resonance imaging therapy. Neurosurgical Clinics of North
America 7: 323-330
m Further reading
Royal College of Radiologists 1998 Making the best use of a
department of clinical radiology, 4th edn. Royal College of
Radiologists, London
63
Influence of coexisting
disease
R. M. Jones, C. A. Marshall
w
Objectives
Recognize which coexisting disease
processes are associated with increased
morbidity.
Understand which features of the patient's
condition can be improved.
Realize that a simple operation does not
always mean an equally simple or risk-free
anaesthetic.
Understand that sick patients are best
managed in daylight hours with fully
trained staff.
Recognize that in some circumstances it
may be better to transfer patients to
another hospital preoperativefy if there
are inadequate facilities for their
postoperative care.
INTRODUCTION
About half of adult patients presenting to you have a
coexisting disease unrelated to the pathological process
necessitating surgery. The proportion is increased in the
elderly and patients presenting for emergency surgery.
The morbidity and mortality associated with surgery and
anaesthesia are increased in patients with coexisting
disease, and the more significant the coexisting disease
the greater the risk (Buck et al 1987, Campling et al 1993).
The medical diagnoses most commonly associated with
increased surgical morbidity and mortality are:
• Ischaemic heart disease
• Congestive cardiac failure
• Arterial hypertension
• Chronic respiratory disease
• Diabetes mellitus (Greek dia — through + bainein = to go
+ mellitus = honeyed)
• Cardiac arrhythmias
• Anaemia
• Obesity.
You can see that pre-existing cardiac-related problems
account for the most significant increase in operative
risk.
The National Confidential Enquiry into Perioperative
Deaths (NCEPOD) for 1990 (Campling et al 1992) empha-
sized the importance of discussion between surgeon and
anaesthetist before a decision to proceed in a particular
patient. All patients presenting for surgery should have a
full clinical history and examination performed, includ-
ing details of concurrent drug therapy, previous medical
history and history of allergy. Depending on the nature of
the coexisting medical disease and that of the planned
surgery, additional specialized investigations may subse-
quently be needed. Young (< 45 years), fit patients under-
going minor elective surgery do not need routine blood
haematology or chemistry, a chest X-ray or an electro-
cardiogram ECG).
The NCEPOD report for 1992-1993 (Campling et al
1995) identified a substantial shortfall in critical care
services, and a failure to anticipate the need for these
services. Furthermore, it emphasized that the skills of the
surgeon and the anaesthetist should be appropriate for
the medical condition of the patient. These professionals
would not always be doctors of the same grade.
Who Operates When (Campling et al 1997), an NCEPOD
report into timing of operations, found that the patients
who died were for the most part elderly and in poor
preoperative health (82% suffered from at least one
coexisting disease, of which cardiorespiratory disease
was the most common, followed by malignancy).
Preoperative management was criticized as sometimes
poor, and the rush to operate before adequate resuscita-
tion contributed significantly to morbidity and mortal-
ity. Particular attention was drawn to the low use of
intravenous fluids, infrequent use of objective cardiac
assessment, and patchy application of thromboembolic
prophylaxis.
The 2001 NCEPOD report Changing the Way We Operate
noted that 95% of patients had coexisting medical prob-
lems at the time of the operation.
64
INFLUENCE OF COEXISTING DISEASE
6
Aims of management
• To diagnose and determine the extent of
pre-existing medical disease.
• To optimize the patient's medical condition
before surgery.
• To ensure that specialized postoperative care
facilities are available if required.
CARDIOVASCULAR DISEASE
fibrillation, Q waves or left ventricular hypertrophy
(LVH), and ventricular premature beats, all detectable on
electrocardiography.
Coronary artery disease
1. Coronary atherosclerosis is the commonest type of
cardiovascular disease; NCEPOD has not previously
been able separately to identify patients with either a pre-
vious myocardial infarction or ischaemic heart disease;
for the first time, however, in 2001, NCEPOD identified
that 60% of the patients had known ischaemic heart
disease at the time of their final operation; an incidence
higher than previously identified by national statistics.
2. Established major risk factors for coronary artery
disease include: (1) age (male > 45 years, female > 55 years);
(2) family history of early myocardial infarction; (3) current
or treated hypertension; (4) smoking; (5) diabetes mellitus;
and (6) low levels of high density lipoprotein (HDL)
cholesterol.
3. High risk procedures (risk of perioperative cardiac
morbidity and mortality > 5%) include major emergency
operations, especially in the elderly, major vascular pro-
cedures including peripheral vascular, and prolonged
surgery (> 3 h) with major fluid shifts.
4. In 1996, the American College of Cardiology and
the American Heart Association issued joint guidelines
for cardiovascular assessment for non-cardiac surgery
(ACC/ AHA Task Force Report 1996). These utilize a pre-
liminary screening step followed by further investiga-
tion where necessary.
5. Assess the degree of activity that precipitates symp-
toms of myocardial ischaemia and note the presence or
absence of congestive heart failure (does the patient also
become breathless on exertion?). Enquire about a history
of arrhythmias (palpitations) and presence of a pacemaker.
Determine blood pressure, height of jugular venous pres-
sure (JVP), cardiac murmurs, lung crepitations, dyspnoea
and evidence of peripheral vascular disease.
6. The most important routine test is the electrocardio-
gram (ECG). Remember that the preoperative ECG is
normal in 20-50% of patients with proven ischaemia. The
ECG is a poor predictor of perioperative cardiac morbid-
ity. However, features shown to be associated with
increased risk include: rhythm other than sinus, atrial
Key points
You should now be able to identify three broad
groups of patients:
• High risk patients such as those with unstable
coronary syndromes, or decompensated
congestive cardiac failure (CCF): delay elective
surgery, consult a cardiologist.
• Intermediate risk patients: proceed with
non-vascular surgery, possibly with the
addition of a beta blocker. Further evaluate for
vascular surgery.
• Low risk patients: proceed with surgery.
7. The basis of management depends on the fact that
myocardial ischaemia will occur whenever the balance
between myocardial oxygen supply and demand is dis-
turbed, such that demand exceeds supply. The major
determinants of myocardial oxygen supply are the
coronary perfusion pressure (the aortic diastolic pressure
minus the left ventricular end-diastolic pressure) and
diastolic time.
8. The major determinants of myocardial oxygen
demand are increasing heart rate, increasing inotropic
state, afterload, which is the impedance to left ventricu-
lar ejection (the systemic arterial pressure is an approxi-
mate determinant of afterload), and preload, which is the
left ventricular end-diastolic pressure.
9. In the perioperative period avoid factors that
decrease supply and /or increase demand. Encourage
smokers to stop for at least 12 h before surgery. Almost
without exception, continue concurrent drug therapy
until the time of surgery. Short term beta blockade may
improve survival after discharge from hospital, although,
in the study by Mangano et al (1996), atenolol was given
under close monitoring and it may not be appropriate
simply to adapt this as an oral premedication to be given
on the ward. It can be seen that an increase in heart rate
and an increase in preload is especially deleterious as
they increase myocardial oxygen demand and decrease
myocardial oxygen supply. During the perioperative
period do not allow a decrease in systemic arterial pres-
sure to a significant degree (a decrease in diastolic pres-
sure greater than 20% of the patient's normal resting
diastolic pressure is a useful guide) because this decreases
coronary perfusion pressure, which is very poorly toler-
ated in patients with multiple sites of coronary artery
narrowing. Ensure that pain management is effective
65
PATIENT ASSESSMENT
postoperatively as the presence of pain leads to hyper-
tension and tachycardia. If necessary, refer the patient to
the hospital's acute pain team. In addition, after major
surgery, especially intra-abdominal or intrathoracic,
administer supplemental oxygen for 24 h. Consider pro-
viding supplemental oxygen overnight for the first four
postoperative days.
10. While myocardial ischaemia is commonest over the
first three postoperative days, myocardial infarction tends
to occur on the day of surgery or on the first postoper-
ative day; therefore, institute invasive monitoring for the
first 24-36 h postoperatively.
Key points
• Coronary artery disease is the commonest
cardiac disease; it is associated with the
majority of perioperative mortality and
morbidity.
• Early postoperative ischaemia is a much
stronger predictor of morbidity and mortality
than any identifiable preoperative factors.
• Acute cardiac failure and unstable angina pose
unacceptably high perioperative risks; treat it
prior to elective non-cardiac surgery.
be due to an increase in volume (an increase in intravas-
cular volume or valve incompetence), or pressure (sys-
temic arterial hypertension or aortic stenosis). It is usual
for one ventricle to fail before the other, but disorders that
damage or overload the left ventricle are more common
(e.g. ischaemic heart disease and systemic arterial hyper-
tension), and hence symptoms attributable to pulmonary
congestion are usually the presenting ones.
2. Left ventricular failure is the most common cause of
right ventricular failure and, if this supervenes, dyspnoea
may actually decrease as right ventricular output
decreases, leading to a reduction in pulmonary conges-
tion. Conventionally, congestive heart failure refers to the
combination of left and right ventricular failure with
evidence of (and symptoms relating to) systemic and
pulmonary venous hypertension. Physiologically, heart
failure may be thought of as the failure of the heart to
match its output in order to meet the body's metabolic
needs. Treatment is aimed at normalizing this imbalance.
Thus, cardiac output can be improved or metabolic needs
decreased. Traditionally, digitalis glycosides have been
thought of as mediating their beneficial effects by improv-
ing cardiac output. Their use is now superseded by
angiotensin converting enzyme (ACE) inhibitors, often
combined with diuretics. Vasodilator's can also be used to
decrease peripheral demand. Digitalization is indicated in
patients with atrial fibrillation or flutter.
Arterial hypertension
1. Moderate or marked, longstanding, untreated
hypertension increases perioperative morbidity and mor-
tality, and is a significant risk factor for the production of
coronary atherosclerosis. Stabilize patients with sustained
systemic arterial hypertension (systolic > 160 mmHg,
diastolic > 110 mmHg) on antihypertensive therapy
before proceeding with long duration elective surgery.
2. Untreated or inadequately treated hypertensives
respond in an exaggerated manner to the stress of surgery,
with a resultant increase in operative morbidity and mor-
tality. Assume that patients with longstanding moderate
to marked hypertension have coronary atherosclerosis
and manage them appropriately, even in the absence of
overt signs and /or symptoms of ischaemic heart disease,
3. Antihypertensive therapy is associated with its own
unique considerations for anaesthetic and surgical man-
agement, the specific issues depending upon the medica-
tion the patient is taking (see Concurrent drug therapy,
p. 80).
Key points
• Manage symptomatic heart failure by optimum
medical therapy preoperatively in all but the
direst of surgical emergencies.
• Surgery in the presence of decompensated
heart failure is associated with a high mortality.
3. The operative mortality and morbidity of patients
with well-compensated heart failure is small. After oper-
ation admit the patient to a high dependency unit or an
intensive care facility with the ability to measure and
adjust preload, afterload and cardiac output. A principal
recommendation of the 2001 NCEPOD report was that
nurses and doctors on the wards need to improve their
proficiency in interpreting and managing central venous
pressure (CVP). Ward equipment must include facilities
for transducer pressure monitoring, to allow accurate and
continuous CVP monitoring.
Heart failure
1. This implies an inadequacy of heart muscle sec-
ondary to intrinsic disease or overloading. The latter may
Congenital heart disease
1 . Congenital anomalies of the heart and cardiovascu-
lar system occur in 7-10 per 1000 live births (0.7-1%). It is
66
INFLUENCE OF COEXISTING DISEASE
. 6
the commonest form of congenital disease and accounts
for approximately 30% of the total burden of congenital
disease. In affected children 10-15% have associated
anomalies of the skeletal, genitourinary or gastrointesti-
nal system. Nine lesions comprise more than 80% of con-
genital heart disease; of these, ventricular septal defect is
by far the most frequent at 35%. Approximately 10-15%
of patients with congenital heart disease may survive
untreated to adulthood but the majority require some
form of cardiac surgery as children.
2. A large cohort of patients with treated congenital
heart disease is now surviving into adult life. Although
these patients have traditionally returned to paediatric
cardiac surgery centres for non-cardiac surgery as adults,
this is not always possible. If the patient has been lost to
cardiac follow-up, request a new cardiological opinion.
Key points
• Adults with congenital heart disease form a
very high risk group, often with multiple
anatomical and pathophysiological
abnormalities.
• Fully assess them preoperatively and request
perioperative care from experts familiar with
these problems.
3. It is not possible to review the subject comprehen-
sively here; read the article by Findlow et al (see Further
reading). In summary, the problems fall into four groups:
arrhythmias, shunts (volume and direction), pulmonary
disease and hypertension, and ventricular dysfunction.
Patients with Eisenmenger's syndrome (right-to-left
shunt due to pulmonary hypertension) are very high risk
patients. As well as circulatory failure, they run the risk
of air embolism during surgery, postoperative deep vein
thrombosis (DVT) and infective endocarditis. Give anti-
biotic prophylaxis to all patients with congenital heart
disease, and take care to avoid air in the tubing during the
siting of intravenous lines.
Acquired valvular heart disease
Mitral stenosis
This is nearly always of rheumatic origin, but symptoms
do not appear until the valve area is reduced to less than
2.5 cm 2 , i.e. half the normal valve area. This may take
20 years following the episode of rheumatic fever. As valve
area decreases below 2 cm 2 , an increase in left atrial pres-
sure is required at rest to maintain cardiac output. A valve
area below 1 cm 2 is classified as severe mitral stenosis and
is associated with a left atrial pressure in excess of
20 mmHg, and even at rest cardiac output may be barely
adequate; there is pulmonary hypertension. Eventually
right ventricular failure supervenes and atrial fibrillation
is common. Patients with mild to moderate mitral stenosis
and sinus rhythm tolerate surgery well. All patients
should receive antibiotic prophylaxis. Fluid balance
should be carefully monitored, as overtransfusion may
precipitate pulmonary oedema, whereas under trans fusion
will compromise left ventricular filling. Similarly, changes
in heart rate are poorly tolerated, and during surgery the
anaesthetist will use a technique which minimizes changes
in cardiac parameters. If major surgery is to be undertaken,
with the possibility of large blood loss, consideration
should be given to monitoring pulmonary capillary wedge
pressure by means of a balloon-tipped flow-directed
catheter. Unless the patient is taking oral anticoagulants, a
local anaesthetic technique may be used for surgery, but a
high spinal or epidural block may be associated with
adverse cardiovascular effects (systemic arterial hypoten-
sion) and should be employed with caution.
Patients who are dyspnoeic at rest and have a fixed
and reduced cardiac output present a significant risk
during surgery. Digoxin should be continued up until the
time of operation and plasma electrolytes checked, as
hypokalaemia will increase the incidence of cardiac
rhythm disturbances. These patients may have to be
ventilated electively postoperatively.
Aortic stenosis
Valvular aortic stenosis is commonest in elderly males,
although it may occur at any time of life. The presence of
any of the following significantly increases the likelihood of
aortic stenosis: effort syncope, slow rise of the carotid pulse,
late systolic murmur with radiation to the right carotid and
absent second heart sound. The aetiology is diverse and
includes congenital, rheumatic, senile and mixed forms. It
must be remembered that it is most common in patients in
whom the incidence of ischaemic heart disease is also high.
Severe aortic stenosis is associated with an increased peri-
operative morbidity and mortality. These patients may be
asymptomatic even with a large (> 80 mmHg) gradient
across the valve, if the left ventricle has not failed. A pre-
operative echo and cardiac assessment is essential to deter-
mine the gradient, as the risk of surgery can be predicted
from this. The 1994-1995 NCEPOD report made the specific
recommendation that any patient with an ejection systolic
murmur in association with evidence of left ventricular
hypertrophy or myocardial ischaemia requires referral to a
cardiologist preoperatively for assessment of the aortic
valve (Gallimore et al 1997). Systemic arterial hypotension
must be avoided at all times because it will compromise
coronary perfusion. Thus, peripheral vasodilatation,
hypovolaemia and myocardial depression are all poorly
67
PATIENT ASSESSMENT
tolerated. A change in cardiac rhythm is also poorly tol-
erated, as the atrial component to ventricular filling is
essential to maintain normal cardiac output. For major
procedures it is advisable to monitor left ventricular filling
pressure, as higher than normal filling pressures are needed
to maintain cardiac output.
Cardiomyopathies
Using echocardiography, three principal forms of cardio-
myopathy are described.
1. Congestive or dilated cardiomyopathy: this may be
associated with toxic, metabolic, neurological and inflam-
matory diseases. There is decrease in contractile force of
the left or right ventricle, resulting in heart failure.
2. Hypertrophic or obstructive cardiomyopathy: this is
an autosomal dominantly inherited condition in which
there is hypertrophy and fibrosis; it mainly affects the
interventricular septum but may involve the whole of the
left ventricle.
3. Restrictive cardiomyopathy: this is a rare form of
cardiomyopathy and the main feature is the loss of
ventricular distensibility due to endocardial or myocar-
dial disease. Restrictive cardiomyopathy in many ways
resembles constrictive pericarditis, and the endocardial
disease may produce thromboembolic problems.
Table 6.1 summarizes the treatment and management
of these patients.
Disturbances of cardiac rhythm
Atrial fibrillation
This is the most commonly encountered disturbance of
cardiac rhythm and it is important to define the disease
processes causing the fibrillation. These are: ischaemic
heart disease, rheumatic heart disease (especially mitral
stenosis), pulmonary embolism, bronchial carcinoma,
thyrotoxicosis, thoracotomy, alcoholism.
If there appears to be no underlying cause, the rhythm
disturbance is usually termed Tone atrial fibrillation'. The
atrial discharge rate is usually between 400 and 600
impulses per minute, but the atrioventricular (AV) node
cannot conduct all these impulses, so that some fail to
reach the ventricle or only partially penetrate the node,
and this results in a block or delay to succeeding
impulses. Ventricular response is therefore irregular, but
seldom more than 200 impulses per minute; the use of
drugs or the presence of disease of the AV node often
causes the response rate to be lower than this. The
medical management of patients with atrial fibrillation
must include the management of the underlying cause of
the rhythm disturbance. It is important to ensure that the
fibrillation is well controlled, i.e. that the response rate of
the ventricle is not too rapid. Digitalis alkaloids remain
the primary method of slowing AV nodal conduction, but
if these fail to control the response rate, amiodarone is
usually effective. Occasionally, cardioversion will restore
sinus rhythm if the atrial fibrillation is of recent onset.
Anticoagulate the patient prior to this.
Atrial flutter
The causes of this disturbance of cardiac rhythm are
similar to those of atrial fibrillation, and the perioperative
considerations are principally those of the underlying
disease process* Atrial flutter is less commonly seen than
atrial fibrillation. Although control of ventricular rate is
more difficult in flutter, unlike fibrillation cardioversion is
often successful. Anticoagulate the patient with warfarin
prior to cardioversion. Second line therapy includes fle-
cainide or digoxin. A bolus of adenosine may be used to
aid in the differential diagnosis of atrial flutter versus
paroxysmal supraventricular tachycardia (SVT).
Table 6,1 Cardiomyopathies: diagnosis and treatment
Congestive {dilated) Hypertrophic (obstructive)
Presenting signs/symptoms
Treatment
Heart failure
Rhythm disturbance
Systemic emboli
Restrictive
Diuretics
Vasodilators
Antiarrhythmics
Anticoagulants
Syncope
Dyspnoea
Angina
Rhythm disturbance
Systolic murmur appearing during
longstanding hypertension
Antiarrhythmics
fi-Adrenergic antagonists
Anticoagulants
Heart failure
Eosinophilia
Steroids
Cytotoxic agents
68
INFLUENCE OF COEXISTING DISEASE
6
Heart block
There are two basic types of heart block: atrioventricular
heart block and intraventricular conduction defects.
Atrioventricular heart block. This may be incom-
plete (first- or second -degree AV block) or complete
(third-degree AV block). In first-degree heart block the PR
interval of the ECG exceeds 0.21 s, but there are no
dropped beats and the QRS complex is normal. It does not
always imply significant underlying heart disease/ but is
seen in patients on digitalis therapy. Do not expose the
patient to any drug in the perioperative period which will
further decrease AV nodal conduction (e.g. halothane
anaesthesia, p-adrenergic antagonists or verapamil).
There are two types of second-degree heart block;
Mobitz types 1 and 2. Mobitz type 1 block is also known
as the 'Wenckebach phenomenon' and this is usually
associated with ischaemia of the AV node or the effects of
digitalis. There is progressive increase in the length of the
PR interval until the impulse fails to excite the ventricle
and a beat is dropped. As a generalization, patients with
this type of heart block do not require a pacemaker prior
to surgery, and should it be necessary the administration
of atropine will often establish normal AV conduction.
Mobitz type 2 block is less common than type 1; it is a
more serious form of conduction defect and may be a
forerunner to complete AV block. The atrial rate is normal
and the ventricular rate depends on the number of
dropped beats, but it is commonly 35-50 beats per
minute. The net result is that of an irregular pulse. The
ECG indicates that there are more P waves than QRS com-
plexes, but the PR interval, if present, is normal. It is prob-
ably acceptable to undertake minor surgery in patients
with Mobitz type 2 block without the need for the inser-
tion of a prophylactic pacemaker. However, in these cir-
cumstances ensure that you have immediately available
drugs such as atropine and isoprenaline, and also the
means for temporary pacing. Prophylactic pacemaker
insertion is indicated for major surgery, especially if this
is likely to result in significant blood loss and associated
haemodynamic instability.
Third-degree heart block is also termed "complete heart
block'. It may result from conduction defects located
within the AV node, bundle of His, or the bundle branch
and Purkinje fibres. An escape pacemaker emerges at a
site distal to the block (e.g. if the impulses are blocked
within the AV node, the bundle of His usually emerges as
the subsidiary pacemaker). In general, the more distal the
site of the escape pacemaker, the more likely is the patient
to suffer symptoms such as dyspnoea, syncope or con-
gestive heart failure and to need permanent ventricular
pacemaker therapy. Pacemaker therapy is always indi-
cated before surgery, although in emergency situations
(such as complete heart block appearing intraoperatively)
various drugs may be tried to increase the heart rate.
Atropine may be of value if the escape pacemaker is junc-
tional. Isoprenaline may be of value if the escape pace-
maker is more distal. A pacing Swann-Ganz catheter or a
transoesophageal pacemaker can be inserted in an emer-
gency and may be easier to place than a temporary wire.
Intraventricular conduction defects. Left bundle
branch block is always associated with heart disease. The
QRS complex is wide (>0.12 s). A hemiblock occurs if only
one of the two major subdivisions (anterior and posterior)
of the left bundle is blocked. The QRS complex is not pro-
longed in left hemiblocks. Left anterior or posterior hemi-
block may occur with right bundle branch block and it is
generally considered that left anterior plus right bundle
branch block is not an indication for temporary pace-
maker therapy before surgery, but that left posterior plus
right bundle branch block is an indication for a pace-
maker. The latter patients are at risk of developing com-
plete heart block. Right bundle branch block is not
invariably associated with underlying heart disease. The
principal significance lies in its association with a left pos-
terior hemiblock, as there is then a risk of complete heart
block; in these patients a temporary pacemaker is indi-
cated before surgery and anaesthesia.
Pacemakers
The patient with a pacemaker can safely undergo surgery
and anaesthesia, but review the medical condition that
gave rise to the need for pacemaker therapy. The usual
indications for a pacemaker are congenital or acquired
complete heart block, sick sinus syndrome and brady-
cardia, associated with syncope and /or hypotension.
Acquired complete heart block is probably the com-
monest indication, the underlying cause for this usually
being ischaemic heart disease. Specifically ask the patient
about the return of symptoms such as syncope, which
may indicate that the pacemaker is failing to capture the
ventricle (or atria if an atrial pacemaker is present). The
heart rate should be within a couple of beats per minute
of the pacemaker's original setting. It is important to
determine the type of pacemaker that has been implanted
and the time when it was put in.
All patients with pacemakers are normally reviewed
regularly in a pacemaker clinic.
Key points
Whenever a pacemaker is in situ, have
atropine, adrenaline (epinephrine) and
isoprenaline available for use in the event of
pacemaker failure.
69
PATIENT ASSESSMENT
• During surgery, diathermy is usually safe, but
place the indifferent electrode as far from the
pacemaker as possible, on the side of
operation, in 1-2 s bursts more than 10 s apart
(Simon 1977).
• Have the anaesthetist ensure that diathermy
has not inhibited the pacemaker function, by
checking the pulse (Aitkenhead & Barnett 1989)
RESPIRATORY DISEASE
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Asthma
Patients with asthma have bronchospasm, mucus plug-
ging of airways and air trapping. These result in a mis-
match of ventilation and perfusion and total effective
ventilation may be severely impaired. A number oi exoge-
nous and endogenous stimuli may produce reversible
airway obstruction. The most active chemical mediators are
histamine and the leukotrienes. Expiration is prolonged,
functional residual capacity and residual volumes are
increased and vital capacity is decreased. Bronchospasm
may be aggravated by anxiety, by instrumentation of the
upper airway by foreign material or irritants in the upper
airway, by pain, and by drugs. The latter include morphine,
papaveretum, unselective p-adrenergic antagonists, and
various anaesthetic drugs including tubocurarine and anti-
cholinesterases. In taking the clinical history, pay special
attention to factors which precipitate an attack, and review
the patient's normal drug therapy. If possible, arrange the
riming of surgery to coincide with a period of remission of
symptoms. Continue the patient's normal bronchodilator
therapy up until the time of surgery, and consider ordering
preoperative chest physiotherapy. Allay preoperative
anxiety, and prescribe suitable premedication - diazepam,
pethidine, promethazine and atropine are free from bron-
chospastic activity. If the patient is taking steroid therapy,
you may need to give additional doses during the peri-
operative period (see Concurrent drug therapy, p. 80). In
the postoperative period, pay careful attention to pain man-
agement and give nebulized or intravenous bronchodila-
tors if necessary. In appropriate cases consider using local
anaesthetic techniques in severe asthmatics. Postoperative
analgesia can be achieved with, if necessary, epidural
blocks.
Indications for intermittent positive
pressure ventilation in asthmatics
• If the patient is distressed and exhausted.
• In the presence of systemic arterial
hypotension or significant disturbance of
cardiac rhythm.
• If the arterial oxygen tension is less than
6.7 kPa or arterial carbon dioxide tension is
greater than 6.7 kPa, associated with an
increasing metabolic acidosis in the face of
maximum medical therapy.
Chronic bronchitis and emphysema
1. Patients who have a cough with sputum production
on most days for 3 months of the year for at least 2 years
have chronic bronchitis. They are often smokers (see
below), and have irritable airways leading to coughing
and some degree of reversible airways obstruction in
response to minimal stimulation.
2. Patients with destruction of alveoli distal to the ter-
minal bronchioles and loss of pulmonary elastic tissue
have emphysema. They experience airway closure with
air trapping and, therefore, inefficient gaseous exchange.
3. Chronic bronchitis and emphysema commonly
coexist in the same patient. Many of the considerations in
the perioperative period that apply to the asthmatic
patient also apply to patients with chronic bronchitis and
emphysema; there are, however, some additional points
to note. These diseases are usually slowly progressive and
may eventually result in a respiratory reserve which is so
low that the patient is immobile and dyspnoeic at rest,
and even speaking and eating may be difficult. Arrange
elective surgery during the months in which symptoms
are least noticeable - usually during the summer. Make
every effort to persuade smokers to quit their habit. If the
patient requires major surgery, and if the disease is severe,
consider performing elective tracheostomy and arranging
postoperative ventilation. These will facilitate the clearing
of secretions, and thus gaseous exchange, during the post-
operative period when diaphragmatic splinting and pain
or respiratory depression may cause acute respiratory
insufficiency.
4. Smokers have about six times the incidence of post-
operative respiratory complications compared with non-
smokers. Cigarette smoking has wide-ranging effects on
the cardiorespiratory and immune systems and on
haemostasis (Jones 1985). They may have arterial carbon
monoxide concentrations in excess of 5%; the resultant car-
boxyhaemoglobin decreases the amount of haemoglobin
available for combination with oxygen, and inhibits the
ability of haemoglobin to give up oxygen (i.e. the oxygen
dissociation curve is shifted to the left). Carbon monoxide
also has a negative inotropic effect. Nicotine increases
heart rate and systemic arterial blood pressure. Thus,
carbon monoxide decreases oxygen supply, while nicotine
increases oxygen demand, and this is of particular signi-
ficance in patients with ischaemic heart disease. It is
especially important that these patients stop smoking for
12-24 h before surgery; this results in a significant
70
INFLUENCE OF COEXISTING DISEASE
6
improvement in cardiovascular function (the elimination
half-lives of carbon monoxide and nicotine are a few
hours).
However, the respiratory effect of smoking, especially
mucus hypersecretion, impairment of tracheobronchial
clearance and small airway narrowing take at least
6 weeks before there is any improvement in function after
smoking cessation. Similarly, the effects of smoking on
immune function (smokers are more susceptible to post-
operative infections) require at least 6 weeks before
improvement occurs. Many smokers complain that they
find it difficult to clear their mucus if they stop smoking,
and use this as an excuse not to stop smoking before
surgery; there may be some substance to this claim, but it
does not outweigh the benefits of stopping. Emphasize the
risks of smoking to smokers, and encourage them to stop
smoking for as long as possible before elective surgery.
I I Key points
• Arrange elective surgery on patients with
chronic bronchitis and emphysema at times of
the year when symptoms are minimal.
• In an emergency encourage smokers to stop
smoking for 12-24 h preoperative ly, especially
if they also have ischaemic heart disease.
• Before elective surgery encourage smokers to
stop for as long as possible before operation.
E N DOCRI N E D YSFU NCTION
Thyroid gland
Excluding diabetes, disorders involving the thyroid gland
account for about 80% of endocrine disease. There are two
practical issues for you and the anaesthetist:
1 . Firstly, there are problems related to the local effects
of a mass in the neck. These include airway problems and
the potential for difficult tracheal intubation.
2. Secondly, there are problems associated with the
generalized effects of an excess or deficiency of
hormone. Before surgery, prepare and render euthyroid
patients with hyperthyroidism, to avoid problems.
Propylthiouracil (average daily dose 300 mg) inhibits
hormone synthesis and blocks the peripheral conversion
of thyroxine to tri-iodothyronine. As a generalization,
the larger the gland the longer it takes to achieve the
euthyroid state. The vascularity of the gland can be con-
siderably decreased by 7 days treatment with potassium
iodide solution. Propranolol is an alternative treatment
to thiouracil: 60-120 mg daily for 2 weeks may be the
only treatment required, and is now routinely used at
many centres.
3. Avoid, if possible, an emergency operation in a
poorly or non-prepared patient because it carries signifi-
cant risk. Cardiovascular complications are potentially
life-threatening so consider giving intravenous esmolol
before induction of anaesthesia (using increments every
5 min to decrease the resting heart rate by 10 beats per
minute). Disturbances of cardiac rhythm, hypoxia and
hyperthermia may all occur. If appropriate, choose a local
anaesthetic technique.
4. Hypothyroidism is not uncommon, especially in
elderly patients. Cardiac output is low and blood loss is
poorly tolerated; however, you must give blood transfu-
sion with caution to avoid overloading the circulation. It
has been said that in hypothyroidism the respiratory
centre is less responsive to hypoxia and hypercarbia, so
that it may be necessary to ventilate patients electively in
the postoperative period. These patients are especially
sensitive to opioid analgesics so use them with caution in
the perioperative period. Monitor the patient's tempera-
ture and prevent hypothermia, as this will aggravate the
circulatory and respiratory depression.
Key point
• Beware the potential complications of missing,
and therefore failing to anticipate,
complications of hyperthyroidism and
hypothyroidism.
Pituitary gland
1. In hypopituitarism, the varying involvement of the
several hormones which the anterior pituitary produces
leads to a variety of clinical presentations: amenorrhoea
in females and impotence in males are common present-
ing features. If hypopituitarism is unrecognized, there is
a greatly increased perioperative risk of hypoglycaemia,
hypothermia, water intoxication and respiratory failure. If
the diagnosis is known, planned substitution therapy is
indicated before surgery. Oral hydrocortisone (15 mg
twice daily) is administered. This is increased during the
operative period; thyroxine is also given and the dose
slowly increased to about 0.15 mg daily and the plasma
thyroxine level is measured.
2. Acromegaly is caused by excessive production
of pituitary growth hormone. This results in overgrowth
of bone, leading to an enlarged jaw and kyphoscoliosis,
as well as connective tissue and viscera. There is
cardiomegaly, early atherosclerosis and systemic arterial
hypertension, and diabetes mellitus is common.
71
61
PATIENT ASSESSMENT
Management should include consideration of all associated
conditions and the anaesthetist will carefully assess the
patient as tracheal intubation may be difficult.
3. Diabetes insipidus (Latin in = not + sapere = to taste;
hence tasteless as opposed to diabetes mellitus = honeyed)
is the result of deficiency of antidiuretic hormone. A water
deprivation test is used to differentiate diabetes insipidus
from compulsive water drinking, and measurements are
made of urine and plasma osmolality. When the plasma
osmolality reaches about 295 mOsmol kg" 1 normal patients
will concentrate their urine, but patients with diabetes
insipidus cannot do so. If the syndrome is differentiated
from compulsive water drinking, the operative manage-
ment of these patients is usually uncomplicated. The
patient should receive a bolus of 100 milliunits of vaso-
pressin intravenously before surgery and during the oper-
ation 100 milliunit h _1 are administered by continuous
infusion. Isotonic solutions, such as 0.9% sodium chloride,
may then be administered with minimal risk of water
depletion or hypernatraemia. Plasma osmolality should
be monitored perioperatively (the normal range is
285-285 mOsmol kg" 1 ).
Adrenal gland
Adrenocorticol insufficiency is known as Addison's
disease. It may present in acute and chronic forms and may
be due to disease of the gland itself or to disorders of the
anterior pituitary or hypothalamus. A patient with adreno-
cortical insufficiency undergoing surgery presents a major
problem. The cardiovascular status of the patient and the
blood glucose and electrolytes must be measured. The
patient is prepared by infusing isotonic sodium chloride
and glucose solutions in order to correct hypernatraemia
and hypoglycaemia. The day before surgery, an intramus-
cular injection of 40 mg methylprednisolone is adminis-
tered. Before induction of anaesthesia a further 100 mg
hydrocortisone is administered, and for major surgery an
infusion of hydrocortisone should be given during the
operation. Hydrocortisone has approximately equal gluco-
corticoid and mineralocorticoid effects. Postoperatively, the
dose of hydrocortisone is decreased from 100 mg twice
daily to a replacement dose of about 50 mg daily
Adrenocortical hyperfunction is commonly iatrogenic.
Whatever the aetiology, these patients will have glucose
intolerance manifest as hyperglycaemia or frank diabetes
mellitus, systemic arterial hypertension (possibly associ-
ated with heart failure) and electrolyte disturbances,
especially hypokalemia and hypernatraemia. Protein
breakdown leads to muscle weakness and osteoporosis.
Muscle weakness will be aggravated by obesity, and
respiratory function should be carefully assessed before
surgery, as well as postoperatively. Osteoporosis may lead
to vertebral compression fractures and patients should be
positioned with great care during surgery. Prolonged
immobilization after surgery will lead to further de-
mineralization of bone, and hypercalcaemia may lead to
the formation of renal calculi. Vitamin D therapy may
therefore be needed in the postoperative period.
Aldosteronism may be primary (an adrenocortical
adenoma - Conn's syndrome), or secondary, in which the
condition is associated with an increase of plasma renin
secretion (e.g. the nephrotic syndrome and cardiac
failure). Patients will have hypokalemia and hyperna-
traemia, which may be associated with systemic arterial
hypertension. If the diagnosis is made before surgery, the
administration of spironolactone (up to 300 mg daily) will
reverse hypertension and hypokalemia.
Phaeochromocytoma
These catecholamine-secreting tumours may produce
sustained or intermittent arterial hypertension. During
surgery, arterial hypertension and disturbances of cardiac
rhythm are common, due to the release of adrenaline
(epinephrine) and noradrenaline (norepinephrine) into
the circulation. Prolonged secretion of these produces not
only arterial hypertension but also a contracted blood
volume; a- and {3-adrenergic blockade will help to reverse
both these effects.
Preoperative a-adrenergic blockade
must not be complete because:
• It may cause preoperative postural syncope.
• It may cause difficulties in controlling the
profound hypotension that sometimes occurs
after tumour removal.
• A rise in systemic blood pressure on tumour
palpation is a useful sign in searching for small
tumours or metastases.
Phenoxybenzamine is the agent usually used to induce
partial a-adrenergic blockade. Careful preoperative
preparation using a- and ^-adrenergic blockade, as well
as the introduction of anaesthetic techniques that promote
cardiovascular stability, have greatly decreased the
mortality of patients undergoing surgery for removal of a
phaeochromocytoma, from 30-45% in the early 1950s to
less than 5% recently.
Pancreas
Diabetes mellitus
Diabetes mellitus is a syndrome characterized by hyper-
glycaemia due to insulin deficiency, impaired insulin
action or a combination of both. It may be primary (most
72
INFLUENCE OF COEXISTING DISEASE
6
cases) or secondary diabetes associated with other
medical problems, such as pancreatitis or steroid treat-
ment. Primary diabetes mellitus is subdivided into type 1
diabetes, characterized by absolute insulin deficiency
(formerly insulin-dependent diabetes mellitus, IDDM)
and type 2 characterized by insulin resistance and relative
insulin deficiency (formerly non-insulin-dependent dia-
betes mellitus, NIDDM). Type 1, which is due to auto-
immune destruction of pancreatic islet [3 cells, is treated
with insulin, whereas type 2 diabetes (whose pathogenesis
is less well understood) may be managed by diet and oral
agents, although many patients will eventually require
insulin for optimal management. Most insulin now used is
bioengineered human sequence insulin. Recently the first
two artificial insulin analogues, lispro and insulin aspart,
have been introduced to clinical practice. These have been
developed by amino acid substitution in the insulin
sequence in order to create an insulin which is absorbed
more rapidly after subcutaneous administration, giving a
faster onset and shorter duration of action.
Sulphonylureas and metformin remain the main oral
hypoglycaemic drugs used in the UK and are safe and
effective. Two other types of oral agent have recently
become available for the treatment of type 2 diabetes.
Acarbose reduces the breakdown of complex carbohy-
drates in the gut and reduces postprandial blood glucose
levels; however, many patients experience excess flatu-
lence, which limits its acceptability. The thiazolinediones
are a new group of drugs that improve insulin sensitivity.
Troglitazone was withdrawn after reports of severe
hepatic toxicity but two further drugs, rosiglitazone and
pioglitazone, have since been introduced. These appear to
be effective when used in combination with either a
sulphonylurea or metformin.
The chronic complications of diabetes include large
vessel disease, microvascular disease, coronary heart
disease and neuropathy. Despite advances in manage-
ment, diabetes is the single greatest cause of end-stage
renal failure requiring replacement therapy. In addition to
coronary heart disease there is a high incidence of asymp-
tomatic myocardial ischaemia. Clinically significant silent
coronary artery disease has been found in 20% of middle-
aged men with type 2 diabetes screened by exercise
testing. The prognosis of myocardial infarction is con-
siderably worse in diabetic patients, with higher early and
late mortality and a greater incidence of left ventricular
failure after infarction. Abnormalities of peripheral or
autonomic nerve function can be found in most patients
with diabetes of long duration. The most common is a
classical symmetrical sensory neuropathy which affects
the feet and legs and can predispose the patient to the risks
of pressure ulceration. Autonomic dysfunction is relatively
rare and symptoms usually relate to postural hypotension.
Before surgery, the cardiovascular status of the patient
should be carefully reviewed and the blood pressure taken
both supine and erect to test for the possibility of auto-
nomic neuropathy. An association between sleep apnoea
and autonomic neuropathy has been documented and res-
piratory arrests have been observed following surgery and
the use of sedative drugs. Patients with symptomatic auto-
nomic neuropathy should therefore be considered to be
at increased risk following anaesthesia, and appropriate
steps taken to monitor respiratory function.
Table 6.2 summarizes the regimens suitable for minor
and more major surgery in diabetics patients who are
either controlled by diet alone, by oral hypoglycaemic
agents, or with insulin.
Chlorpropamide is a sulphonylurea with a very long
duration of action, and hypoglycaemia is a particular
concern in patients taking this agent; it should be stopped
48 h before planned surgery and the blood sugar measured
regularly after the patient becomes nil by mouth.
Table 6.2 Severity of diabetes
Controlled by diet
Controlled by oral agents
Controlled by insulin
Type of surgery
Minor
No specific precautions
Omit medication on morning of operation
and start when eating normally
postoperatively
Intermediate/major
Measure blood glucose 4 hourly: if
>12 mmol ! ! start glucose-potassium-
insuiin sliding scale regimen
Omit medication and monitor blood
glucose 1-2 hourly; if >12 mmol I" 1
start glucose-potassium-insulin
sliding scale regimen
Unless very minor procedure (omit insulin when nil by mouth) give glucose-
potassium-insulin sliding scale regimen during surgery and until eating normally
postoperatively
73
PATIENT ASSESSMENT
Patients taking long-acting insulin preparations should
be converted to Actrapid insulin, and surgery should be
scheduled for the early morning if possible. A number of
regimens for blood sugar control have been described,
but the following is easy to use.
Infuse 10% glucose 500 ml + 10 mmol potassium chlor-
ide (KC1) at 100 ml h~ l . Prepare a 50 ml syringe contain-
ing 50 units of Actrapid (short-acting) insulin in 50 ml
normal saline (= 1 unit ml -1 ) and connect via a 3-way tap
to a glucose infusion. Adjust the rate of the syringe driver
according to the following sliding scale:
Blood glucose
<5
5-7
(mmol 1"
] )
Rate of syringe driver (ml h ! )
Switch off
1
7-10
10-20
>20
2
3
4
If two successive blood glucose values are > 20 mmol 1~\
leave instructions to consult the duty doctor.
The blood sugar is measured at least 2-hourly during
surgery and the amount of insulin adjusted to maintain
the blood sugar between 6 and 12 mmol H. Following
surgery, blood sugar and plasma potassium are measured
at least 4-hourly. Sepsis and high dose corticosteroid treat-
ment markedly increase insulin requirements.
Postoperatively, as soon as the patient starts eating,
those who are normally treated with oral hypogly-
caemics may need subcutaneous insulin for a few days
before oral therapy is recommenced. Patients normally
treated with insulin can be converted to Actrapid insulin
to a total equal to the normal preoperative dose. After
3 days the original regimen can usually be restarted (i.e.
using long-acting insulins). In the perioperative period
lactate-containing fluids (e.g. Hartmann's solution)
should be avoided in diabetics. If oral feeding has not
started within 72 h of surgery, consideration should be
given to the institution of parenteral nutrition.
Obesity
Life expectancy is decreased by obesity, and operative
morbidity and mortality increase with increasing weight.
In moderate obesity, the individual presenting for surgery
should be instructed to decrease weight and be given
dietary advice appropriate to the patient's social and eco-
nomic circumstances. They should also be examined care-
fully for the presence of conditions with which obesity is
commonly associated; these include diabetes mellitus and
systemic arterial hypertension. Patients who are double
or more their ideal weight are usually termed 'morbidly
obese'. These patients present a number of problems to
both surgeon and anaesthetist. Their preoperative cardio-
respiratory status should be assessed carefully and, as
these patients are at an increased risk of inhalation of
gastric contents, all should receive appropriate antacid
therapy before surgery. Obesity is one of a number of con-
ditions that will lead to an increase in postoperative deep
vein thrombosis and associated thromboembolic phe-
nomena; obese patients should receive appropriate pre-
operative prophylaxis for this. Transport and positioning
of morbidly obese patients may cause difficulties, and
occasionally two standard operating tables used side by
side may be needed. Intravenous access may be difficult
and non-invasive methods of monitoring arterial blood
pressure may be inaccurate; therefore, an intra-arterial
line is indicated for all but the most minor procedures.
This will also enable arterial blood gases to be monitored
in the intraoperative and postoperative periods. Patients
may need continued ventilatory support after surgery.
BLOOD DISORDERS
*J0k£-£^&5-^^^
Primary blood disorders produce a wide range of clinical
manifestations, which may affect any organ in the body.
Conversely, there are nearly always some changes in the
blood accompanying general medical and surgical dis-
orders. Thus, haematological investigations form an
important part of the assessment and subsequent moni-
toring of most disease processes.
Anaemia
This is defined clinically as a reduction in haemoglobin
level below the normal range for the individual's age and
sex. It becomes clinically apparent when the oxygen
demand of the tissues cannot be met without the use of
compensatory mechanisms. The level of haemoglobin at
which elective surgery should be postponed has been
under review and many guidelines have been revised
downwards. This is due to concern over the dangers of
transmissible agents in blood which may not, as yet, be
detectable. An acceptable level will depend on factors such
as whether there is a known cause for the anaemia, the
nature of surgery planned, and the physical fitness of the
patient. A haemoglobin concentration of 8-10 g dl -1 may be
adequate for minor surgery. It is important to realize that
blood transfusion to raise the haematocrit should be
carried out at least 48 h before the operative procedure, as
this period of time will allow full recovery of the stored
erythrocytes' oxygen-carrying capacity. In order to mini-
mize the risk of transmitting the human immunodeficiency
virus (HIV), blood transfusion should be undertaken only
if the urgency of surgery necessitates this. Tissue oxygena-
tion appears to be maximal at around a haemoglobin con-
centration of 11 g dl -1 (tissue oxygenation depends upon
cardiac output, peripheral vascular resistance, blood
74
INFLUENCE OF COEXISTING DISEASE
6
viscosity and blood oxygen-carrying capacity). Patients
with ischaemic heart disease are likely to suffer more from
the consequences of decreased oxygen-carrying capacity
from untreated anaemia, and it is especially important to
treat preoperative anaemia in these patients.
exclude a hereditary bleeding diathesis (one-third of
haemophilia patients show no family history). Many sys-
temic diseases may be complicated by bleeding, as may
treatment with a number of drugs which can cause bone
marrow depression leading to thrombocytopenia.
Haemoglobinopathies
This term encompasses a range of different genetic con-
ditions, which can be broadly divided into two groups:
the structural variants and the thalassaemia syndromes.
The thalassaemia syndromes are due to the abnormal pro-
duction of one or more globin chain; there are several
hundred variants, but they have no implications for
anaesthetic or surgical practice. The main structural
mutation with clinical significance is sickle haemoglobin.
Haemoglobin S is an abnormality in the amino acid
sequence of the haemoglobin. When a deoxygenated
haemoglobin molecule becomes distorted, this may lead
to capillary occlusion and tissue hypoxia. The disease is
inherited and it may be in the heterozygous or homozy-
gous form. The former (HbAS) does not usually cause
problems during surgery as the molecular distortion,
known as 'sickling', only occurs at very low oxygen satu-
rations. However, in the homozygous state (HbSS) there
is a real risk of sickling during surgery and this may cause
tissue infarction. Screening tests are available for the pres-
ence of haemoglobin S, and electrophoresis is used to
determine the exact nature of the abnormality. During
surgery it is important to avoid low oxygen tensions and
thus an elevated inspired oxygen concentration is used,
and the patient is kept warm and well hydrated in order
to maintain cardiac output and avoid circulatory stasis.
These patients are prone to dehydration because of renal
papillary damage and the resultant passage of large
volumes of dilute urine. If very major surgery is planned,
where there is the possibility of perioperative hypoxia, for
example pulmonary surgery, an exchange transfusion
should be considered in an attempt to reduce the level of
haemoglobin S to below 25%. Patients with haemoglobin
C and haemoglobin SC should be managed in a similar
way to those with haemoglobin SS.
Bleeding and coagulation disorders
As a generalization, purpura, epistaxis and prolonged
bleeding from superficial cuts are suggestive of a platelet
abnormality, and bleeding into joints or muscle is sug-
gestive of a coagulation defect. Both forms may be con-
genital or acquired and it may be possible to differentiate
these from the patient's history, a recent onset being
indicative of an acquired disorder. A family history
should be sought but it must be remembered that the
absence of other relatives with a positive history does not
Platelet disorders
Thrombocytopenia arises from a number of causes:
• Failure of megakaryocyte maturation
• Excessive platelet consumption
• Hypersplenism.
Bone marrow disorders leading to failure of maturation
may be due to hypoplasia or infiltration. Increased
consumption occurs in disseminated intravascular coagu-
lation, idiopathic thrombocytopenic purpura and certain
viral infections. Sequestration in an enlarged spleen
occurs in lymphomas and liver disease. Spontaneous
bleeding does not usually occur until the platelet count
has decreased to 30 x 10 9 l -1 . Treatment has to be directed
at the underlying disease, but thrombocytopenia resulting
in clinically important bleeding necessitates a platelet
transfusion. Ideally, the count should be increased to
100 x 10 9 l" 1 , but transfusing platelets until a clinically
acceptable effect is attained is often performed. Routine
major surgery should not be undertaken in the presence
of an abnormal platelet count until the result is confirmed
and the cause identified.
Haemophilia
Before surgery in patients with haemophilia A or B, the
concentration of the coagulation factors should be
increased to a level that will minimize bleeding, and this
concentration should be maintained until healing has
occurred. It is important to seek specialist advice in deter-
mining the dosage of factors required. Cryoprecipitate
and fresh frozen plasma or factor IX fraction are used to
manage bleeding episodes, but the patients should be
tested for antibodies to the products. If these are present,
only life-saving operations should be contemplated. If
cryoprecipitate or freeze-dried factor IX concentrate are
administered, complications, including viral hepatitis
and possibly prior transmission, may occur. Recombinant
(genetically engineered) factor VIII and IX are now avail-
able and are the treatment of choice.
RENAL DISEASE
Chronic renal failure
This is said to be present when chronic renal impairment,
from whatever cause, results in abnormalities of plasma
75
PATIENT ASSESSMENT
biochemistry. Usually, this happens when the glomerular
nitration rate (GFR) has fallen to less than 30 ml min 1 . Fluid
balance is precarious in these patients; they may have a
very limited ability to excrete water and /or sodium.
Management before surgery depends on the severity of the
renal failure. Moreover, in a situation of renal insufficiency,
anaesthesia and surgery may precipitate acute renal failure.
Patients in late and terminal degrees of chronic renal failure
(GFR < 10 ml min -1 ) may already have commenced on
dialysis. If not, dialysis should be performed before surgery
if at all possible. Dialysis does not reverse all the adverse
effects of chronic renal failure; for example, systemic
arterial hypertension and pericarditis may still be present.
In addition, patients who are dialysed very soon before
surgery may have cardiovascular lability during anaes-
thesia and surgery because they may have a relatively
contracted blood volume. These patients are also vulner-
able to infection, anaemia, blood coagulation defects,
electrolyte disturbances and psychological problems.
Systemic hypertension is a constant feature of chronic renal
failure and arteriovenous shunts may cause a hyper-
dynamic circulation with a low systemic vascular resist-
ance, predisposing the patient to myocardial ischaernia.
These patients may depend on an increased minute venti-
lation to maintain respiratory compensation for their
metabolic acidosis, and respiratory compromise postoper-
atively may exacerbate their poor metabolic condition. It is
important to define the degree of renal failure present
before surgery, and review the dialysis regimen. Blood bio-
chemistry, coagulation and haemoglobin must be checked.
Care should be taken when prescribing potentially nephro-
toxic drugs and consideration given to pathways of drug
elimination (see Concurrent drug therapy, p. 80). A careful
search should be made for the presence of occult infection
and all patients should have a preoperative chest X-ray. The
susceptibility to infection is compounded in transplant
patients by the administration of immunosuppressive
drugs, and prophylactic antibiotics may be necessary pre-
operatively and postoperatively. Chest physiotherapy may
also be needed. Procedures such as arterial or central
venous cannulation must be carried out under strict aseptic
conditions. Before, during and after surgery, fluid and
electrolyte balance must be very carefully monitored.
Nephrotic syndrome
The clinical association of heavy proteinuria, hypoalbu-
minaemia and generalized oedema is usually referred to
as the "nephrotic syndrome'. The hypoalbuminaemia is
the result of urinary albumin loss and the syndrome
becomes apparent if more than 5 g of protein are lost per
day, and the plasma albumin concentration falls to less
than 30 g 1 _1 . It is important to define the underlying cause
of the nephrotic syndrome. Before surgery, the plasma
protein and electrolyte levels must be estimated and cor-
rected as indicated. An albumin infusion (up to 50 g) will
restore circulating blood volume and may in itself initiate
a diuresis. An alteration in plasma proteins will cause
changes in drug effect due to an alteration in drug
binding. The anaesthetist may use more conservative
doses of some drugs. Central venous cannulation is
advisable for all but the most minor surgery.
U^RJCHSEASE^^
Chronic liver disease is a continuum of pathophysiology,
from the patient with an abnormality of liver function
tests with no adverse physiological consequences to the
patient with severe end-stage liver disease who repre-
sents an extreme surgical risk. Patients with liver disease
were classified for general surgical risk by Child and
Turcotte in 1964 (Table 6.3) and this is still valid today. The
only important addition is the observation that pro-
thrombin time is the most significant preoperative pre-
dictor of mortality in patients undergoing surgery for
variceal bleeding.
A patient with moderate to severe cirrhosis has numer-
ous pathophysiological changes affecting various organ
systems and should always be managed by experienced
personnel, both anaesthetic and surgical. Child and
Turcotte grade C (even in the absence of coma) carries a
very high perioperative mortality, even for elective
surgery. Although it is impossible to review the patho-
physiology of end-stage liver disease in this text, concise
reviews are available (see Further reading).
Tat
L 1 l^B - BIM
Table 6.3 Child's classification for hepatic functional reserve
Sefum bilirubin <mg dl 1 )
Serum albumin (g dl *)
Ascites controlled
Neurological disorder
Nutrition
A (Minimal)
B (Moderate)
C (Advanced)
<2.0
2.0-30
>3.5
3.0-3.5
None
Easily controlled
None
Minimal
Excellent
Good
>3.D
<3.0
Poorly controlled
Advanced 'coma'
Poor 'wasting'
76
INFLUENCE OF COEXISTING DISEASE
6
Organ systems affected by cirrhosis
• Cardiovascular system
• Lungs
• Kidneys
• Brain
• Gut
• Coagulation
• Immunocompetence.
Prior to surgery the patient's condition must be opti-
mized. All patients should be screened routinely for
hepatitis B viral infection. They must be kept adequately
hydrated to preserve renal function (although paradoxi-
cally they may be on diuretics to control ascites).
Respiratory function may be poor due to basal atelectasis
and/or intra pulmonary shunts. Ascitic drainage may
improve the situation. If renal function deteriorates in the
face of adequate filling, a low dose dopamine infusion
should be started. These patients are prone to sepsis and
spontaneous bacterial peritonitis so body fluids should be
cultured and strict aseptic precautions adhered to. Finally
their coagulation will be deranged. In patients with
predominantly cholestatic disease this may improve with
vitamin K injection. Patients with hepatocellular disease
are likely to have a combination of clotting factor defi-
ciencies, chronic fibrinolysis and a low platelet count. The
situation is best assessed and treated using a dynamic
measure of clotting - thromboelastography (Mallett &
Cox 1992).
These patients often lose large amounts of blood at
operation due to a combination of surgical (varices) and
medical (coagulopathy) causes; in addition they have a
very high cardiac output and low systemic vascular re-
sistance circulation, which is often unresponsive to nor-
adrenaline (norepinephrine). It cannot be overemphasized
that these are very high risk patients to operate on.
NEUROLOGICAL DISEASE
Multiple sclerosis
The aetiology of this disease of temperate climates
has become clearer in recent years. It appears that in
genetically susceptible individuals activated T cells and
macrophages responding to environmental triggers inter-
act with type 1 astrocytes, causing a disruption of the
blood-brain barrier and a leak of immune mediators into
the nervous system. This causes demyelination. Patients
may present for incidental surgery or surgery associated
with alleviation of the complications, e.g. implantation of
extradural stimulating electrodes. In order to decrease
perioperative morbidity, careful preoperative examin-
ation is needed. Patients may have a labile autonomic
nervous system associated with postural hypotension.
Muscle atrophy may lead to significant kyphoscoliosis
and this may result in a restrictive form of pulmonary
disease. Urinary tract infections commonly occur, but the
patient must be carefully examined to identify other infec-
tive foci. An elevation in temperature is the one definite
factor known to precipitate an exacerbation of the disease,
so all but the most urgent surgery should be postponed
until the patient is free from infection. Epilepsy is not
uncommon in patients with multiple sclerosis.
Epilepsy
This term refers to a variety of types of recurrent seizure
produced by paroxysmal neuronal discharge from
various parts of the brain. Seizures may have a cerebral
cause (e.g. tumour) or be due to a systemic disorder (e.g.
uraemia or hypercalcaemia). The symptomatology is
variable and seizures may cause total loss of conscious-
ness or only a minimal alteration in awareness. The
disease occurs in all age groups, with an incidence of
about 1%. About 75% of patients have no recognizable
underlying cause. If there is an underlying cause, the
surgical management should take this into account.
Otherwise management is usually uncomplicated; it is
important that the patient's usual anticonvulsant medi-
cation be continued until the time of surgery and
restarted as soon as possible postoperatively, if necessary
using parenteral drug administration (see Concurrent
drug therapy, p. 80). Anticonvulsant drugs such as pheny-
toin lead to induction of liver microsomal enzymes, and
thus the patient's response to a variety of drugs that may
be given during the perioperative period may be altered.
Myasthenia gravis
This is an autoimmune disease of the neuromuscular junc-
tion, involving the postjunctional acetylcholine receptors.
Specific autoantibodies have been identified and micro-
scopic changes in the membrane demonstrated. The disease
is characterized by muscle weakness of fluctuating sever-
ity, most commonly affecting the ocular muscles. Facial and
pharyngeal muscle weakness also occurs, leading to
dysarthria and dysphagia. It can occur at any age in life but
is most frequently seen in the fourth decade. There is an
association with thymic enlargement and thymomas, both
benign and malignant. About two-thirds of patients
without a thymic tumour will improve after thymectomy,
although the outlook is less good for patients with tumour,
whether this is excised or not. Inhibitors of the enzyme
cholinesterase (e.g. edrophonium, neostigmine and pyrido-
stigmine) are used in the treatment of myasthenia gravis, as
77
PATIENT ASSESSMENT
are drugs which suppress the immunological response and
eliminate circulating antibodies. The latter have now
become the first line of treatment, and 90% of patients will
benefit from the use of azathioprine or steroids.
Patients may present for thymectomy or incidental
surgery, and the surgical management depends upon the
nature of the operation and severity of the disease. As
usual, the patient's normal medication must be continued
up until the time of surgery. If the disease is severe, or
major thoracic or upper abdominal surgery is planned,
elective postoperative ventilation is advisable and,
occasionally, a tracheostomy will be required, but this
should only be needed if ventilation is prolonged and
excess secretions are a problem. Respiratory failure in
myasthenic patients may be secondary to either a myas-
thenic or a cholinergic crisis. Assisted ventilation should
be instituted and anticholinesterase drug therapy
stopped, and then cautiously reintroduced after testing
with small doses of intravenous edrophonium (2-5 mg).
Elective postoperative ventilation may also be advisable
for lesser forms of surgery, including thymectomy, if the
patient's preoperative vital capacity is less than 2 litres or
there is a history of intercurrent respiratory problems.
Following surgery, the requirements for anticholinester-
ase and other drug therapy may be changed and it is
important to titrate drug dosage against clinical response.
It should be remembered that overtreatment can cause
weakness, just as can undertreatment. Postoperatively,
the adequacy of ventilation can best be assessed by
repeated blood gas measurement and, therefore, before
surgery there are advantages to the placement of an
intraarterial line. This will also facilitate accurate cardio-
vascular monitoring during surgery.
ALCOHOLISM AND DRUG ABUSE
Addiction is characterized by psychological dependence,
change in tolerance and a specific withdrawal syndrome.
Drugs, including alcohol, are used by susceptible indi-
viduals in order to obtain oblivion or excitement.
Aetiological factors include psychiatric illness, personal-
ity disorders and social pressures. It should be remem-
bered that many addicts abuse more than one drug. In
general, it is advisable to maintain normal doses of the
addict's usual drug in the immediate pre- and postoper-
ative periods. The perioperative period is not the best
time to attempt to wean a patient from an addiction and
it may only serve to precipitate an acute withdrawal reac-
tion. Addicts may not admit to their addiction and the
first sign that there is a problem may be the appearance
of a withdrawal syndrome.
Specific organ damage may result from drug addic-
tion. Alcohol gives rise to liver damage and can progress
to cirrhosis, and thus a change in protein synthesis,
altered glycogen storage and susceptibility to hypogly-
caemia. In addition, alcoholics are prone to bleeding,
especially from the gastrointestinal tract, and there may
be hypomagnesaemia. They may also have cardiomy-
opathy, and careful assessment of cardiovascular status
is necessary in the alcoholic patient. Solvent or glue snif-
fers may have hepatic or renal damage and bone marrow
suppression. Addicts to opioids will often have used con-
taminated needles and syringes, and there is a high inci-
dence of hepatitis and liver damage and also of infection
with the HIV virus (see below). If sudden hypotension
occurs in the operative or postoperative period in a nar-
cotic addict, and if other obvious causes are excluded,
this may respond to the administration of intravenous
morphine.
PSYCHIATRIC DISEASE
Anxiety and concern are a normal reaction of patients to
forthcoming surgery and anaesthesia. A significant pro-
portion of the population will suffer from an affective dis-
order at some time in their lives. A depressive illness is
the commonest affective disorder and treatment may
involve psychotherapy, antidepressant drug therapy or, if
the disorder is severe, electroconvulsive therapy. It is
important that the patient's preoperative drug therapy is
continued, although both tricyclic antidepressants and
monoaminoxidase inhibitors significantly interact with
the drugs used during anaesthesia (see Concurrent drug
therapy, p. 80). Before surgery both a psychiatrist and an
anaesthetist should be consulted. Many anaesthetists
would prefer that the drugs be continued up until the
time of surgery, and their anaesthetic technique modified
to take account of the potential for drug interactions. It
should not be forgotten that severe affective disorders are
accompanied by a very significant mortality rate in terms
of suicide, and supportive drug therapy should not auto-
matically be withdrawn before planned surgery unless
there is a very good reason to do so. The postoperative
course in patients with a depressive illness may be more
prolonged and these patients should be treated with
appropriate forbearance.
ACQUIRED IMMUNE DEFICIENCY
SYNDROME (AIDS)
This is caused by infection with a retrovirus, the human
immunodeficiency virus (HIV). Acquired immunodefi-
ciency syndrome is now a worldwide epidemic with an
estimated 33 x 10 6 persons infected. The recent decline
78
INFLUENCE OF COEXISTING DISEASE
6
in death rates from HIV in developed countries has been
due to the expanding use of antiviral drugs; however,
resistance to the new drugs has developed in as many
as 20% of patients and, although life expectancy has
increased, these drugs do not represent a cure. HIV infec-
tion may also be seen in patients who have received
infected blood products (e.g. haemophiliacs). The disease
is not very infectious and is transmitted primarily in
blood, and there is little evidence to support transmission
via saliva or airborne transmission. The risk of occupa-
tionally acquired HIV is low (compared for example to
hepatitis B) and it is estimated that the risk of develop-
ing HIV after percutaneous exposure to HIV infected
blood is 0.3%. The risk after comparable exposure to
hepatitis B virus (HBV) is greater than 30%, and HCV
1.9%. Occupational health departments all have their
regimen of postexposure prophylaxis and should be con-
tacted immediately in the event of a needlestick injury
from a high risk patient.
THE PATIENT WITH A TRANSPLANTED
ORGAN FOR NON-TRANSPLANT
SURGERY
The era of transplant surgery dawned in the 1950s with
the first kidney transplant (see Ch. 25). It is therefore not
uncommon now to be faced with a patient with a trans-
planted organ presenting for non-transplant surgery.
Some aspects of management are common to all
patients. It is essential to continue with their immuno-
suppressant regimen but consideration should be given to
whether they are exhibiting signs of toxicity from the
medication. These patients are all immunosuppressed.
Apply strict aseptic precautions. Are they suffering from
an infectious complication that may be due to an unusual
pathogen such as a fungus? Have they developed a
tumour as a consequence of the immunosuppression? The
incidence of lymphomas is increased in these patients.
Finally, are they displaying signs of rejection? This may be
difficult to differentiate from infection in, for example, a
lung graft.
Some specific considerations in a cardiac transplant
recipient are as follows. The heart is denervated; it will be
preload dependent to achieve an adequate cardiac output.
There will be a delayed heart rate response (e.g. to
hypoxia^ which will be generated by catecholamine
secretion. These patients have accelerated coronary
atherosclerosis but may not develop angina in response to
myocardial ischaemia. The heart will have unusual
responses to vasoactive drugs due to the denervation.
Finally, arrhythmias and a low cardiac output may be
signs of rejection.
SURGERY IN THE ELDERLY
Although patients over the age of 65 years comprise only
22% of the surgical caseload/ they are reported to account
for 79% of perioperative deaths (Buck et al 1987). The
mortality of surgery in elderly patients is significantly
higher in those suffering from serious coexisting medical
conditions. In a study of 100 000 surgical operations/ the
relative risk of dying within 7 days, comparing patients
over 80 with those under 60 years, was 3, but the risk
factor comparing patients having symptomatic medical
disease with those having none was over 10 (Cohen et al
1988). Not only do elderly patients have an increased like-
lihood of coexisting disease, but physiological function in
general decreases with age. As a generalization, many
physiological functions (e.g. cardiac output, glomerular
filtration rate and renal blood flow) decrease by about 1 %
per annum after the age of 30 years. Respiratory function
also declines with age (maximum breathing capacity
decreases from about 100 1 min" 1 at 20 years to 30 1 min 1
at 80 years). The elderly are also more sensitive to the
majority of drugs that might be used in the perioperative
period (e.g. diazepam has a half-life measured in hours
that is approximately equal to subject age in years). As in
all other situations where a patient presents for surgery
with a significant coexisting disease, the morbidity and
mortality associated with surgery can be reduced to a
minimum after careful preoperative evaluation and by
optimizing the patient's condition.
If the decision is made to operate on an elderly patient
then that must include a decision to provide appropriate
postoperative care/ which may include high dependency
or intensive care support. Hypotension and hypo-
volemia are common and should be corrected before
surgery whenever possible. Fluid imbalance can con-
tribute to serious postoperative morbidity and mortality
and is more likely in the elderly, who may have renal
impairment or other comorbidity. Accurate monitoring,
early recognition and appropriate treatment of fluid
balance are essential. Non-steroidal anti-inflammatory
drugs should be prescribed with particular caution in
elderly patients in the postoperative period.
Finally, the NCEPOD report Extremes of Age (1999) found
that, in the elderly, unsuspected gastrointestinal complica-
tions are commonly found at post mortem to be the cause,
or contribute to the cause, of death following surgery.
Key points
« Fluid management in the elderly is often poor;
it should be accorded the same status as drug
prescription.
79
PATIENT ASSESSMENT
Elderly patients have a high incidence of
coexisting disorders and a high risk of early
postoperative death.
surgery, there are a number of drugs whose administra-
tion or dosage will need to be modified before surgery
(see Table 6.4 for the more important examples of these).
CONCURRENT DRUG THERAPY
It is a general rule that any patients stabilized on long-term
drug therapy should continue to take their normal medica-
tion until the time of surgery, and that this should be recom-
menced as soon as possible after surgery. If the patient is
unable to take drugs by mouth, appropriate parenteral
administration is required. This is especially important for
patients taking drugs such as antiepileptics, antiarrhyth-
mics or antihypertensives. A thorough knowledge of the
pharmacokinetic and pharmacodynamic profile of the indi-
vidual drugs is needed in order that the appropriate doses
and interval between doses is arrived at for parenteral
administration. A number of drugs (e.g. propranolol)
undergo extensive first-pass liver metabolism after oral
administration, and drugs such as this need much lower
doses administered parenterally than they do orally.
Admission to hospital for surgery gives the opportu-
nity to review the appropriateness of long-term drug
therapy and dosage; this may be especially important in
elderly patients as they are more likely to suffer from
toxic symptoms. The nature of some operations may
mean that the need for continued drug therapy has to be
reviewed postoperatively, or the dosage of the drugs may
need to be altered. An example of this would be a myas-
thenic patient undergoing thymectomy. Although the
majority of patients stabilized on long-term therapy
should continue their normal drugs up until the time of
Summary
• If there is a reversible feature to the
patient's coexisting medical disease,
elective surgery should be postponed until
the patient is optimally treated.
• It may be appropriate to delay even
emergency surgery until the patient's
condition is stabilized or improved.
• A patient presenting for a minor surgical
procedure may none the less require a
high degree of anaesthetic expertise.
References
ACC /AHA Task Force Report 1996 Guidelines for perioperative
cardiovascular evaluation for non-cardiac surgery. Journal of
the American College of Cardiology 27: 910-948
Buck N, Devlin HB, Lunn JN 1987 The report of a confidential
enquiry into perioperative deaths. Nuffield Provincial
Hospitals Trust, London
Burke M, Callum KG, Gray AJG et al 2001 Changing the way
we operate. NCEPOD, London
Callum KG, Gray AJG, Hoile RW 1999 Extremes of age.
NCEPOD, London
Table 6,4 Some important drugs, the administration or dosage of which needs to be modified before surgery
Oral contraceptives
Anticoagulants
Agents used in diabetes
Levodopa
Monamine oxidase inhibitors
Steroids
Maintain for minor or peripheral procedures and institute prophylaxis against
deep vein thrombosis before surgery. Stop one complete monthly cycle before
abdominal (especially pelvic) surgery
Stop oral agents several days before surgery and substitute heparin if continued
anticoagulant is necessary. The action of heparin can be rapidty reversed
with protamine
See section on diabetic management
Omit dose before surgery
Significant potential for drug interactions, causing severe physiological
disturbance, Discuss with psychiatrist and anaesthetist and treat each case on its
merits
Supplement with hydrocortisone 100 mg i.v. 30 min before surgery, repeated
3-hourly during surgery, reducing slowly postoperatively to the patient's
preoperative dose. Treat similarly if taking large dose regularly any time during
3 months before surgery
80
INFLUENCE OF COEXISTING DISEASE
6
Campling EA, Devlin HB, Hoile RW, Lunn JN 1992 The report
of the national confidential enquiry into perioperative deaths,
1990. King's Fund Publishing, London
Campling EA, Devlin HB, Hoile RW, Lunn JN 1993 The report
of the national confidential enquiry into perioperative deaths,
1991/1992. King's Fund Publishing, London
Campling EA, Devlin HB, Hoile RW, Lunn JN 1995 The report
of the national confidential enquiry into perioperative deaths
1992/1993. King's Fund Publishing, London
Campling ER et al 1997 Who operates when? NCEPOD, London
Child CG III, Turcotte J 1965 Surgery and portal hypertension.
In: Child CG III (ed) The liver and portal hypertension.
Saunders, Philadelphia
Cohen MM, Duncan PG, Tate RB 1988 Does anaesthesia
contribute to operative mortality? JAMA 260: 2859-2863
Gallimore SC, Hoile RW, Ingram GS, Sherry KM 1997 The
report of the national confidential enquiry into perioperative
deaths 1994/1995. NCEPOD, London
Jones R M 1985 Smoking before surgery: the case for stopping.
BMJ 290: 1763-1764
Mallett SV, Cox D 1992 Thromboelastoplasty. British Journal of
Anaesthesia 69: 307-313
Mangano DT, Layug EL, Wallace A et al 1996 Effect of atenolol
on mortality and cardio-vascular morbidity after non
cardiac surgery. New England Journal of Medicine
335: 1713-1720
Simon A 1977 Perioperative management of the pacemaker
patient. Anesthesiology 16: 127-131
Further reading
Find law D, Doyle E 1997 Congenital heart disease in adults.
British Journal of Anaesthesia 78: 416-430
Mclntyre N, Benhamon JP, Bircher J et al 1991 Oxford textbook
of clinical hepatology. Oxford University Press, Oxford See
especially section 31: Surgery, anaesthesia and the liver
81
Immunity in surgery
P. L Amlot, C 5. Gricks
Objectives
Appreciate the functions and components
of the immune system.
Recognize that most disease processes are
prevented by innate immunity.
Recognize that specific disease processes
are prevented by adaptive immunity.
Understand the implications of immune
processes in surgery.
INTRODUCTION
The immune system evolved to protect the body from infec-
tion. Innate (inborn) immunity provides common effector
mechanisms that protect against a wide range of pathogens.
As pathogens evolved to escape control by the innate
immune system, co-evolution of adaptive immune mech-
anisms developed, providing specific and variable recep-
tors that can recruit effector mechanisms already provided
by innate immunity that has been evaded by the pathogen.
mj^l^HMMUNITY
Innate (Latin natus = to be born) immunity needs no prior
contact with a pathogen to be activated and there is no
'learning' phase. The innate immune mechanisms are
maximally effective the first time a pathogen is met and
the response does not change with repeated exposure to
pathogens. Clinically pathogenic organisms are broadly
defined by their ability to cross epithelial surfaces and to
evade other innate immune mechanisms; for example,
mycobacterial cell walls are resistant to acid, and cholera
has a specific receptor to bind to the gut wall.
Physical barriers
A large part of innate immunity is mechanical and
applies to pathogens that have no selective method of
crossing intact epithelial surfaces. Damage to skin by pen-
etrating wounds and burns, or to mucosal surfaces by
perforation, allow normally non-pathogenic organisms to
cause disease. Epithelial cells do not function purely as a
mechanical barrier but they produce intracellular chemi-
cal messengers known as cytokines and molecules that
enhance the adaptive immune system's response. These
physical barriers are reinforced by secretions.
Secretory system
Lysozyme in saliva and tears digests peptidoglycan in bac-
terial cell walls. Bacteria with susceptible cell walls are
rendered non-pathogenic. Gastric acid inhibits bacterial
growth and mucus inhibits bacterial motility.
The complement system consists of many proteins that
can self-assemble to cause lysis of cells to which they
are attached. Complement may be activated by two
pathways:
• Alternative pathway - initiated directly by xenogeneic
molecules, such as sugars forming part of microbial cell
walls
• Classical pathway - initiated by antibody and requires
adaptive immunity.
Complement, C-reactive protein and mannose-binding
protein can all coat foreign particles, making them more
easily digestible by phagocytes in a process called 'opson-
ization.' Opsonization (G opsonein = to prepare food for;
hence, make more digestible by phagocytes), by comple-
ment and antibody makes phagocytosis by granulocytes
1000 fold more efficient.
Cellular system
Phagocytes - neutrophils, monocytes or tissue macrophages
- possess a wide variety of receptors, capable of increasing
in quantity but not in quality. The receptors recognize
xenogeneic (Greek xenos = foreign) molecules not present
on human tissues, such as mannose, for which receptors
are expressed on macrophages. Other, non-phagocytic
cells may facilitate the immune response. For example,
82
IMMUNITY IN SURGERY
7
stimulated mast cells release factors that increase vascular
permeability, allowing more rapid access of leucocytes to
sites of infection. Many of the receptors expressed by leu-
cocytes enable their movement through blood vessels and
include selectins, adhesion molecules and chemokines.
Natural killer (NK) lymphocytes are unlike other lym-
phocytes and lack specific receptors capable of qualitative
change. NK cells are involved in the surveillance of
altered cells, particularly against tumours and viruses.
Activated NK cells are capable of killing nucleated target
cells, unless they are inhibited. On the membranes of NK
cells are killer inhibitory receptors (KIRs) which bind to
self-MHC (major histocompatibility complex) class I
molecules of target cells, protecting them from being
killed. Both viruses and tumour cells interfere with, or
eliminate, MHC class I on the surface of their transformed
cells. Although this allows the cells to escape surveillance
by the adaptive immune system, it makes them suscepti-
ble to NK cells, since KIR now has nothing with which to
bind and inhibition of killing does not occur.
Dendritic cells within the epithelium, especially the epi-
dermis where they are known as Langerhans cells, play
an important role in carrying antigens from the skin to
local lymph nodes, where an adaptive immune response
can be generated.
The response of the innate system is amplified in an
integrated manner. For example, complement breakdown
products are chemotactic (Greek taxis = arrangement;
power to attract) for neutrophils, encouraging phagocytic
removal of complement-coated bacteria.
Deficiencies of innate immunity
Primary immunodeficiencies affecting the innate system are
very rare and carry the same consequences as acquired
or iatrogenic deficiency, which is common. Operative
surgery is naturally a major violator of epithelial barriers
and secretions through incisions, intravascular lines,
catheters, anaesthesia and drug use, including anaesthe-
sia. Widespread desquamation, as with burns, severely
compromises innate immunity. There is no known defi-
ciency of lysozyme, but achlorhydria is associated with
infection and malignancy. Deficiency of complement
leads to susceptibility to infection by encapsulated bacte-
ria or, surprisingly, to autoimmunity (Greek autos = self).
Low neutrophil counts reflect the status of an important
component of innate immunity and lead rapidly to severe
consequences because of the wide range of infectious
processes that require this final common phagocytic
pathway. Neutropenia following administration of cyto-
toxic drugs can lead to severe infection within a few days.
It is a key feature of deficiencies in innate immunity that
they lead rapidly to infectious complications because
most, if not all, infection is ultimately controlled by it. The
chances of meeting any of a wide range of infectious
organisms is high and the time to a chance encounter,
including organisms in our own digestive system, is
therefore short.
ADAPTIVE IMMUNITY
In the adaptive response, exposure to infection leads to
qualitative changes of specific receptors. The cells that
bear these receptors compete in a darwinian fashion for
binding to pathogens. The molecular structure that stimu-
lates an adaptive, specific receptor is known as an antigen.
Adaptive immunity has two collaborative branches,
antibody- and cell-mediated immunity.
ANTIBODY-MEDIATED IMMUNITY
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Antibodies belong to a class of proteins known as
immunoglobulin. In humans, antibody-producing B lym-
phocytes originate in the bone marrow and the B cell
receptor is the membrane-bound form of antibody
secreted into body fluids. Pathogens coated with antibody
can fix complement by the classical pathway and are
phagocytosed (Greek phagein = to eat) far more rapidly
than uncoated pathogens. It is estimated that our B cell
system can create more than 10 11 unique antibody
molecules but each B cell can produce antibody of only a
single specificity. There is not enough DNA to encode all
the possibilities and the mechanism of shuffling and
mixing discrete genes coding for immunoglobulin is
known as gene rearrangement. This occurs randomly and
allows B cells to create antibodies with diverse specifici-
ties and includes the possibility of creating antibodies that
react with "self, which can lead to autoimmunity.
Antibody-binding region
Antibody in the B cell membrane acts as a receptor for
antigen on its surface. The B cell may be stimulated by the
binding of an antigen to undergo proliferation, become a
memory B cell or differentiate into a plasma cell. B cell
stimulation by antigen occurs mainly within lymphoid
follicles (structures in which B cells aggregate) and gen-
erates germinal centres, where a process known as somatic
hypermutation takes place. This occurs in 0.1% of cell divi-
sions and allows a few B cells to develop antibodies that
bind to antigen with greater affinity. Normally, within 2
weeks the affinity of the antibody increases by 10- to 100-
fold in the mutated B cells and allows them to compete
successfully against other B cells for antigen, leading to
their preferential proliferation- a process known as clonal
expansion.
83
PATIENT ASSESSMENT
Antibodies: structure and synthesis
One part of the antibody, the variable or V region, binds
to the antigen. The other part, the constant or C region,
interacts with the invariable receptors of the innate
immune system. An antibody is composed of at least two
heavy and two light chains of immunoglobulin linked
together so that there is a minimum of two antigen-
binding sites per molecule (Fig. 7.1). This explains why
antibodies can cross-link antigens and cause agglutina-
tion, for example, during the testing for blood group in
transfusion or in the immobilization of flagellated
microorganisms.
The constant domain is the major part of the antibody
and is so named because it is largely invariable, which
endows the antibody with different functional properties.
There are five heavy chain genes giving rise to
immunoglobulin: IgM, IgD, IgG, IgE and IgA. Immature
B cells usually express IgM but they can switch the
Antigen
Granulocyte
Macrophage
Fig, 7.1 Antibody structure and effector relationships.
VL, variable region of the light chain; VH, variable
region of the heavy chain; CL r constant region of the
light chain; CH, constant region of the heavy chain that
consists of three domains. Note that there are two
binding sites to the antibody molecule, each binding an
identical antigen (1 and 2). Granulocytes and
macrophages bind to antibody molecules via their Fc
receptors (known as Fc because it is an old term for the
constant region of the heavy chain of the antibody
molecule). The complement system interacts with the
constant region of the heavy chain and leads to lysis of
cells.
constant region when stimulated by antigen. The switch
is influenced by the environment and T helper cells. This
is called isotype switching.
IgM is so named because in its secreted form it is a
microglobulin composed of five immunoglobulin
molecules bound together. Because of its large size it is
largely retained within the vascular system, where it is
effective at complement fixation and in protection against
blood-borne infections. IgD is a largely membrane-bound
immunoglobulin of unknown function. IgG is the most
abundant isotype (Greek isos = equal; of the same type) in
the blood and tissues. It is small enough to diffuse readily
in the tissues and contains most of the high affinity anti-
body. There are several subclasses, each with different
functional properties. Apart from coating pathogens for
phagocytosis, they are also able to induce antibody-
dependent cellular cytotoxicity (ADCC), which may play
a part in transplantation and tumour immunity Because
it can cross the placental barrier it provides the fetus with
antibody protection. IgG and IgA are also provided in
breast milk. IgA can be transported across mucosal epithe-
lium, resists gastrointestinal digestion and is the principal
isotype in respiratory and gastrointestinal secretions. It is
thought to prevent adherence of microorganisms and
toxins to receptors and so is sometimes termed 'antiseptic
paint". IgE is bound to receptors on blood basophils and
mast cells, in skin, mucosa, connective tissues and along
blood vessels. Antigen binding causes degranulation of
mast cells, which release mediators invoking coughing,
sneezing, vomiting and diarrhoea. IgE protects against
infestation with worms but causes allergies such as hay
fever, urticaria, asthma and anaphylaxis.
Monoclonal antibodies and flow cytometry
In a normal immune response many B cells produce many
different types of antibodies - a polyclonal response. A
single B cell can produce only a single antibody; when a B
cell proliferates, each daughter cell produces the same anti-
body - a monoclonal antibody - unless somatic mutation
occurs during division. Monoclonality is characteristic of B
cell malignancy and high levels of monoclonal antibody
are recognized as paraprotein in multiple myeloma. These
paraproteins can be detected by electrophoresis or
immunofixation. Kohler and Milstein in 1975 fused a single
B cell from a mouse spleen to a myeloma cell line, allow-
ing infinite production of monoclonal antibodies with
defined antigen specificity. Monoclonal antibodies of
mouse or rat origin have revolutionized diagnostic pro-
cesses and have enabled the identification of many cellular
molecules. As monoclonal antibodies to lymphocyte recep-
tors and antigens were being generated, a prototype
fluorescein activated cell sorter (FACS) was being built.
These flowcytometers are able to detect and count cell-
84
IMMUNITY IN SURGERY
7
bound fluorochromes, allowing rapid counting of cells
expressing specific antigens. Furthermore, up to four
different fluorochromes on the same cell can be detected.
This has enormously increased the scope for measuring
minor cell populations within blood and other fluids. FACS
machines are used to count CD4 and CD8 subsets of
patients with human immunodeficiency virus (HIV),
identify leukaemic, lymphomatous or other malignant cells
and assess the activation status of lymphoid cells, simply
by counting fluorochrome labels bound to monoclonal
antibodies of the appropriate specificity.
Deficiency of antibody-mediated immunity
and bacterial infections
Antibody deficiency predisposes predominantly to bacte-
rial infection. Immunodeficiency of B cells is relatively
uncommon but should be excluded in patients suffering
repeated infections, especially infections recurring after an
adequate course of antibiotic therapy. The slow tempo of
infection due to antibody deficiencies means that the diag-
nosis is often delayed by several years. Antibody defi-
ciency occurs at birth in primary agammaglobulinaemia
(Bruton's disease) but more frequently later on in life as
common variable immunodeficiency (CVID). Acquired
immunodeficiency is often iatrogenic (Greek iatros =
physician, hence resulting from medical treatment), and
as a result of diseases affecting B cells, such as lymphoma.
Corticosteroid therapy is the most common iatrogenic
cause of poor antibody production. It is yet to be seen
what effect the widespread use of the recently licensed
anti-B cell monoclonal antibody, rituximab, will have
upon iatrogenic immunodeficiency. Bacterial infection can
be treated in patients with hypogammaglobulinemia by
replacement immunoglobulin therapy every 2-A weeks,
• Specific operations may have an effect on bacterial infec-
tion from a combination of reduced innate immunity and
antibody deficiency. Splenectomy in children, particu-
larly infants, increases their susceptibility to infection
and children should be given long-term oral penicillin.
There is a lesser risk in older children and adults.
Overwhelming postsplenectomy infection, usually with
encapsulated bacteria such as Pneumococcus, Haemophilus
or Meningococcus spp, occurs in 1-20% of splenectomized
individuals; it is fatal in 50% of cases.
Key point
Give polyvalent pneumococcal vaccine,
Haemophilus (HIB) and meningococcal vaccine
to boost antibody levels before elective
splenectomy.
The small bowel is richly supplied with T, B and
plasma cells and secretes the immunoglobulin IgA
into the lumen. If it is diseased, it becomes suscepti-
ble to infection with, for example, Giardia lamblia.
Remarkably, extensive bowel resection does not
appear to have major immunological effects.
T CELLS AND CELL-MEDIATED
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T lymphocytes have specialized membrane-bound T cell
receptors (TCR) that are not secreted and remain cell
bound. T cells arise in the bone marrow but migrate to the
thymus, a primary lymphoid organ, in order to differen-
tiate. The thymus is a site of enormous cellular prolifer-
ation, like the germinal centres in B cell follicles; it is most
active early in life and atrophies with age.
The T cell receptor, like immunoglobulin, is made up of
two chains. It shows remarkable similarity to the heavy
and light chains of immunoglobulin in that they undergo
the same process of gene rearrangement, producing a
unique antigen-binding variable region and a conserved
constant region which is largely anchored in the T cell
membrane.
T cell recognition of antigen
T cells can recognize only protein antigens that have been
broken down or 'processed' by antigen-presenting cells
(APCs). Peptide fragments from proteins are incorporated
into specialized cell surface molecules that have been
misnamed the major histocompatibility complex (MHC)
because of the complications this region causes in trans-
planting tissues. The MHC is also known as HLA (human
leucocyte antigens). T cell receptors recognize the combi-
nation of the MHC and the peptide antigen that it 'pre-
sents'. T cells cannot recognize free antigen or antigen
outside the context of the MHC.
There are two major classes of MHC molecules, struc-
turally related but differing in their tissue expression, the
subcellular compartment in which they process peptides
and the presentation to separate T cell populations.
MHC class I molecules are present on most nucleated
cells and bind endogenous (Greek endon = within +
gentian = to produce; formed within the cell) peptides that
originate in the cell's cytoplasm. Cells degrade cytoplas-
mic proteins and transport peptides to the cell surface in
MHC class I molecules where they are recognized by
cytotoxic T cells, identified by the CD8 molecule (a
surface antigen that can be detected with a specific mono-
clonal antibody - CD = cluster designation). Cytotoxic T
cells that recognize an MHC class I viral peptide complex
on the surface of a virally infected cell will kill the cell.
85
PATIENT ASSESSMENT
MHC class II molecules are located on B lymphocytes,
macrophages and dendritic cells, collectively known as
antigen-presenting cells. These cells can assimilate exoge-
nous antigen from outside the cell by phagocytosis or
receptor-mediated endocytosis into vesicles within the
cell. During the process of MHC class II synthesis it incor-
porates the peptides from the vesicles and transports it to
the cell surface. The T cell receptor of T helper cells, iden-
tified by the CD4 molecule, is capable of binding to the
antigen bound to the MHC class II molecule. T helper and
cytotoxic T cells are selected in the thymus (Fig. 7.2).
In both types of MHC a molecular groove exists into
which peptides can fit, facilitating interaction with the
T cell receptor. Pathogens with peptide sequences that
cannot bind to specific MHC molecules are ignored. To
counter this, the MHC gene cluster on chromosome
6 accommodates highly polymorphic (Greek polys = much
+ morphe - form; many formed) genes; this benefits the
population at the expense of the individual and explains
Positive
CORTICAL
Negative
MEDULLARY
Fig. 7.2 Thymic 'education' in T cell differentiation.
CD4 = T helper cells; CDS = cytotoxic T cells. During
'positive' selection T cells express both CD4 and CD8.
Those cells capable of binding to MHC molecules on
cortical epithelial cells are destined to survive. During
'negative' selection, T cells express either CD4 or CDS,
selected on the ability of the T cell receptor (TCR) to
bind to MHC class II or class I, respectively. During
'negative' selection, avid binding of TCR to MHC
expressing self-antigens on medullary dendritic cells
leads to the apoptotic death of such T cells, thus
minimizing autoimmunity. Cells depicted with small
nuclei represent apoptotic cells destined for elimination
in the thymus. Binding ability of the TCR for MHC is
depicted by the degree of 'fit' between the two
molecules.
why some individuals are more susceptible to specific
infections than others.
T cell function
The T cell receptor detects MHC 'signatures' of non-self
and in turn is linked to intracellular enzymatic pathways
that activate the T cell via a complex of molecules known
as CD3. The activated T cell produces intercellular
messengers known as cytokines, of which more than 50
have been identified, with many different effects. Most of
them transmit between leucocytes and are therefore
termed interleukins (IL), and the different types and actions
are designated by a number, e.g. IL-1, IL-2 to IL-n.
Inhibition of cytokines is the basis of selective immuno-
suppressive drugs such as ciclosporin and tacrolimus
which inhibit the secretion of IL-2.
The T cell response, directed by T helper cells, is modi-
fied by the antigenic context (microenvironment) and
may in some situations cause cellular destruction, includ-
ing suicide of the target cell - apoptosis (Greek apo = away
+ ptosis = a falling), or in other situations enhance anti-
body production in order to clear or inhibit antigens (see
Fig. 7.3). The T cell recognition of 'self 7 is largely due to
ignorance, in that most self-reactive T cells are eliminated
in the thymus.
Deficiency of cell-mediated immunity and
infections by viral and other intracellular
pathogens
The rare failure to develop a thymus, resulting in severe
deficiency of T cells, is known as DiGeorge's syndrome
Antigen
Fig. 7.3 T helper cell (CD4) functions. APC, antigen
presenting cell; MHC, major histocompatibility complex;
IL, interleukin; T H 0, T H 1, T H 2, T helper cell subsets (CD4+);
TNF, tumour necrosis factor; IFN, interferon; TGF, T cell
growth factor; T ct cytotoxic T cell (CD8+); Mo,
monocyte/macrophage series; B, B cell.
86
IMMUNITY IN SURGERY
7
(after the American paediatrician who described it).
Much more common are acquired T cell deficiencies, of
which acquired immune deficiency syndrome (AIDS) is
the best known. The human immunodeficiency virus
(HIV) selectively infects T helper cells, resulting in sus-
ceptibility to intracellular infections and virally mediated
malignancies such as lymphomas (human herpes virus
4-HHV-4) and Kaposi's sarcoma (HHV-8). Remarkably,
thymectomy carried out for the treatment of myasthenia
gravis or during cardiac surgery does not appear to have
severe effects on immunity. Among the acquired forms of
predominantly T cell deficiency are:
1 . Malignant disease.
2. Surgical operations, including the response to
trauma as well as anaesthetic drugs such as halothane.
3. Infection, particularly viral effects on lymphoid
cells.
4. AIDS, which results from infection with HIV. It ini-
tially affected male homosexuals, intravenous drug users
and haemophiliacs given factor VIII derived from pooled
plasma from the USA. More recently in Europe and the
USA and elsewhere in the world, most notably Africa, it
has become primarily a heterosexual disease. The virus
attaches itself to the CD4 molecule on the helper T cell,
while cytotoxic T cells are initially unaffected. It is parti-
cularly associated with susceptibility to opportunistic
infections such as Pneumocystis carinii, cytomegalovirus,
Aspergillus and in certain circumstances the development
of Kaposi's sarcoma.
5. Deficiency caused by radiotherapy for malignant
disease, which produces lymphopenia, neutropenia and
thrombocytopenia and largely depresses cellular immu-
nity; however, the dose and rate of irradiation is such
that marked cytopenias are rare and infection is not as
common as with cytotoxic drugs.
6. Deficiency resulting from the use of immuno-
suppressant drugs such as azathioprine, cyclosporin A or
tacrolimus used in transplantation.
Deficiency of both T and B cell immunity
The rare failure of lymphocyte differentiation leads to an
absence of both B and T cells and a condition known as
severe combined immune deficiency (SCID). This immuno-
deficiency of the adaptive immune system is the most likely
to present rapidly but even then takes several months from
birth to be diagnosed, after repeated infections, failure to
thrive and diarrhoea. As in each form of defects in adaptive
immunity, the tempo is much slower than that seen with
deficiency of innate immunity. Acquired forms of combined
immunodeficiency are the result of:
1. Poor nutrition, which affects both cell-mediated
immunity and antibody production.
Key point
• Postoperative infection rates are likely to be
higher in countries where starvation is
common.
2. Chemotherapy to treat malignant disease, which is
cytotoxic to neutrophils, leucocytes and lymphocytes. It is
associated with increased bacterial and opportunistic infec-
tions, of which the effects on innate immunity predominate.
3. The administration of glucocorticoid steroids, which
are used in transplantation and in treatment of autoimmune
diseases, with potent effects on both arms of adaptive
immunity as well as some on innate immune mechanisms.
AUTOIMMUNITY
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Random generation of antigen-binding sites in antibodies
risks the development of autoimmune disease. One safe-
guard against autoantibodies is that immature B cells
emerging from the bone marrow are sensitive when their
antibody receptor binds to self proteins, leading to toler-
ance or death by apoptosis. Another safeguard is that
B cells require a number of growth factors (cytokines)
derived from T cells, and in their absence B cell differen-
tiation and antibody production may fail. Autoimmunity
arises in genetically predisposed individuals, affecting
both B and T cells. Autoantibody may mediate disease by
a number of immune mechanisms:
• Binding to and blocking important physiological recep-
tors, such as the acetylcholine receptor in myasthenia
gravis
• Damaging cells and tissues by complement fixation or
antibody-dependent cellular cytotoxicity (ADCC)
• Forming immune complexes that are deposited on
the intimal surface of blood vessels and causing
vasculitis.
Immune deficiency is closely associated with auto-
immunity; for example, Crohn's disease, which may have
an autoimmune component and is often treated with
immunosuppressive drugs, coeliac disease and atrophic
gastritis are all associated with immune deficiency.
TRANSPLANTATION
Autotransplantation (Greek autos = self) of tissue, such as
a skin graft, has no immunological consequences; nor does
grafting between identical twins (isograft: Greek isos =
equal). Non-vascularized allografts (Greek alios = other),
87
PATIENT ASSESSMENT
such as corneal grafts, do not normally evoke a cellular
rejection. On the other hand, kidney, liver, heart, lung,
pancreas, small bowel and bone marrow grafts induce
rejection (see Ch. 25). Allografts are mainly cadaveric
organs but there is increasing use of live related donors.
Bone marrow allografts are from live donors and may be
related or unrelated. Rejection of allografts is predomi-
nantly acute and cell-mediated early in the course of trans-
plantation, unless the recipient has had prior contact with
the donor tissues or is of a different blood group, in which
case hyperacute rejection occurs. A slower onset of chronic
Vascular' rejection, causing graft dysfunction and pro-
gressive graft loss, is due to a variety of mechanisms,
including cell- and antibody-mediated responses, physical
effects, accelerated vasculopathy and immunosuppressive
drug-induced effects. Tubular structures, such as blood
vessels and biliary ducts, are affected by this process.
Avoiding rejection
1. Except when transplanting the cornea, the donor
and recipient tissues are matched for ABO blood groups
and as closely as possible for human leucocyte antigens
(HLA). In addition, the recipient's serum is cross-matched
with the donor lymphoid cells to exclude preformed cyto-
toxic antibodies.
2. Except when transplanting between identical twins,
the recipient is immunosuppressed, with agents selected
from a variety of drugs, including corticosteroids, azathio-
prine, mycophenolate mofetil, ciclosporin, tacrolimus and
sirolimus. The anchors of current therapy are still
ciclosporin and tacrolimus, whose action prevents the
development of cytotoxic T cells; however, both are nephro-
toxic. Antilymphocytic globulin (ALG) or antithymocyte
globulin (ATG) are polyclonal antibodies preferably raised
in rabbits, and may be used to increase immunosuppres-
sion early in transplantation. Monoclonal antibodies such
as OKT3 (CD3) or Campath 1 (CDw52) have been used to
reverse acute rejection. Newer monoclonal antibodies react-
ing with the IL-2 receptor (CD25) are effective at prophyl-
actically reducing acute rejection episodes.
3. Graft versus host disease (GVHD) may develop if the
graft contains competent T cells which react against the
host cells that are incapable of rejecting them. This is most
likely to develop following bone marrow transplantation.
GVHD predominantly affects the skin, liver and gut.
CANCER IMMUNOLOGY
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Immunosuppressed patients have a higher than normal
risk of malignancy, especially skin cancers and lym-
phoid tumours.
Cancers are often infiltrated with lymphocytes and
macrophages - this may be associated with an
improved prognosis.
Latent cancers, especially of the thyroid and prostate
glands, are often disclosed at postmortem examination,
suggesting that the tumours develop but lie dormant
for many years without clinical disease. This has been
attributed to immune mechanisms.
Tumour antigens
Specific antigens can be found on the surface of tumour
cells, especially those that are virally induced, without
being present on normal cells of this type. Some tumour
cells express antigens normally found only in fetal
tissue, such as a-fetoprotein (AFP) and carcinoembry-
onic antigen (CEA). These may be used as markers for
some cancers or to monitor progress by measuring
serum levels, but there is little evidence that they act as
targets for the immune system. Radiolabeled mono-
clonal antibody to CEA may be used to localize residual
bowel tumour. Malignant cells can overexpress proto-
oncogenes on their surface, which contribute to
malignant behaviour; these were identified by anti-
bodies developed for the recognition of specific tumour
types.
Monoclonal antibodies that attach to receptors highly
expressed in tumours can be labelled with isotopes such
as m In and 99m Tc. These can be identified by external
scintigraphy. This is especially valuable in identifying
residual tumour following treatment.
• The occasional but well documented spontaneous
regression of tumours suggests that immunity may
develop against cancers.
Immunotherapy
The identification of immune aspects of cancer has led to
the search for therapeutic uses, especially for dissemi-
nated tumour cells beyond the scope of conventional
treatment, or residual tumour following treatment.
Antibodies alone are rarely cytotoxic to tumour cells and
are largely restricted to haemopoietic malignancy.
Monoclonal antibodies can be conjugated to radioiso-
topes, immunotoxins or enzymes. Radiolabeled antibod-
ies can target highly expressed epidermal growth factor
receptors (GFRs) in lung and brain tumours and there is
hope that monoclonal antibodies to GFRs will be effective
in treating tumours. Monoclonal antibody to Her-Neu has
proven effective in a minority of breast cancers express-
ing this on the tumour.
88
IMMUNITY IN SURGERY
7
Summary
• Do you understand that the immune
system is composed of humoral and
cellular elements and is made up of innate
and adaptive mechanisms?
• Are you aware that normally the immune
system distinguishes self from non-self but
autoimmunity may develop in predisposed
individuals?
• Do you recognize that immune deficiency
arises from many causes, including
operation, which predisposes to
postoperative complications?
• Are you aware that except in specific
circumstances, organ transplants must be
protected from rejection by
immunosuppressive drugs and other
techniques?
• Can you foresee the immunological
aspects of cancer becoming increasingly
valuable in identifying, monitoring and
treating malignancy?
References
Kohler G, Milstein C 1975 Continuous cultures of fused cells
secreting antibody of predefined specificity. Nature 256(5517):
495-497
Further reading
Goldsby RA, Kindt TJ, Osborne BA, Kuby J 2003 Immunology,
3rd edn. W H Freeman, New York
Janeway CA, Travers P, Walport M, Shlomchik M (eds) 2001 The
adaptive immune response. In: Immunobiology, 5th edn.
Churchill Livingstone, Edinburgh
Medzhitov R, Janeway CA 2000 Innate immune recognition:
mechanisms and pathways. Annual Review of Immunology
173:89-97
Norman D, Turka L 2001 Primer on transplantation, 2nd edn.
Blackwell Science, Oxford
Stites DP, Terr AI, Parslow TG 1997 Medical immunology.
Appleton & Lange, Stamford CT
89
Haematological assessment
and blood component therapy
C P. F. Taylor, A. B. Mehta
Objectives
• Understand the need for preoperative
detection of blood abnormalities which
may affect the outcome of surgery and
anaesthesia.
• Be aware of the range of blood
components available for clinical use.
• Understand how to use blood components
appropriately and the hazards associated
with their use.
• Be aware of alternatives to allogeneic
blood transfusion and know when they
are appropriate.
• Understand the underlying mechanisms
and management of excessive intra- or
postoperative blood loss.
INTRODUCTION
This chapter outlines the investigation and management
of patients undergoing surgery. It includes patients who
have a prior abnormality of their blood count or blood
plasma constituents and also discusses appropriate use of
blood components in patients with no prior haemato-
logical problems.
Anaemia and excessive bleeding are symptoms and not
diagnoses. An accurate diagnosis is an essential step in the
formulation of a management plan. In the majority of hos-
pitals, a clinical haematologist will be available to advise
you on optimum use of laboratory diagnostic facilities,
interpretation of results and appropriate therapy. Make
sure you discuss problems early, and take advice on the
appropriate specimens to send and tests to order. If a result
is puzzling, go and discuss it with the haematologist.
PREOPERATIVE ASSESSMENT
Growing pressure on hospital beds and increasing use of
day surgery means that the preoperative assessment
should, wherever possible, be performed prior to admis-
sion. This allows for efficient use of hospital resources and
limits the number of cancelled operations. The key aims
are to assess a patient's fitness to undergo surgery and
anaesthesia, anticipate complications, arrange for sup-
portive therapy to be available perioperatively and to
liaise with the appropriate specialists regarding non-
surgical management. This assessment needs to take
place at a presurgical clinic at least 1 month prior to the
planned date of surgery.
Preoperative planning
Arrange for the patient to attend a preoperative clinic at
least 4-6 weeks prior to operation, to:
• Take a full history and examination, including previous
surgical episodes and bleeding history
• Arrange full blood count, group and antibody screen,
routine chemistry, coagulation screen (if indicated) and
tube for haematinics assessment (ferritin level for iron
stores, vitamin B 12 and folic acid), which can be put on
hold pending full blood count (FBC) results
• Consider autologous predeposit if the patient is fit
enough and there is a greater than 50% likelihood of
significant blood loss requiring transfusion
• Consider using erythropoietin (Greek erythros = red
+ poiesis - making), even with normal haemoglobin,
at a dose of 600 units /kg weekly for 4 weeks
preoperatively
• Prescribe iron and folic acid supplement if there is any
suspicion of iron deficiency
• Establish whether the patient is taking regular aspirin,
non-steroidal anti-inflammatory drugs (NSAIDs) or
warfarin and make necessary arrangements to stop this
drug preoperatively
• Consider a staged surgical approach in major surgery
After the clinic, ensure that all the results of the above
tests are seen within a few days so that you can take necess-
ary action. In addition, discuss with the anaesthetists
whether acute normovolaemic haemodilution (ANH) or
intraoperative cell salvage may be appropriate.
90
HAEMATOLOGICAL ASSESSMENT AND BLOOD COMPONENT THERAPY
8
Anaemia
1. Anaemia is defined as a reduction in haemoglobin
concentration below the normal range after correction
for age and sex (approximately 13—16 g dl -1 in males,
11.5-15 g dl -1 in females). The most common causes of
anaemia in surgical patients are iron deficiency (from
chronic blood loss) or anaemia of chronic disease. Both
may be due to the underlying condition for which
operation is required.
2. Every anaemic patient, that is those whose
haemoglobin level is below their laboratory normal range,
should have iron studies and ferritin levels performed
sufficiently in advance of operation to allow for corrective
measures to take effect. A subnormal ferritin indicates iron
deficiency and the patient should be treated preoper-
atively with iron supplements orally or intravenously
Defer elective surgery until the maximum haemoglobin is
attained. One should not use allogeneic blood unless there
are no reasonable alternatives (Table 8.1).
Key point
• Anaemia in elective surgical patients should be
assessed and appropriately treated
preoperative I y,
3. A normal or high ferritin level does not exclude iron
deficiency (although it is less likely), as ferritin is an acute
phase protein. Anaemia of chronic disease (ACD) may be
present in many presurgical patients, including those
with malignancy or joint disease requiring orthopaedic
surgery. ACD is usually normochromic and normocytic,
although it is sometimes slightly microcytic. Iron levels
Table 8.1 Reasons to reduce blood exposure
Immunological complications
- Red eel! alloantibodies: HTR
- HLA antibodies; refractoriness
- TRALI, FTP, TA-GvHD, etc
Errors and 'wrong blood' episodes
Infections - bacterial, viral, ? prion
Immunomodulation - infection, malignancy
Litigation
Resource
HTR, haemolytic transfusion reaction; PTP, post-
transfusion purpura; TRALI, transfusion-related
acute lung injury; TA-GVHD, transfusion-associated
graft versus host disease.
are normal but iron-binding capacity is reduced (in
contrast to iron deficiency where iron-binding capacity
is raised). Ferritin (an intermediary in the absorption
of iron from the gut) may be normal or raised. ACD
may respond to erythropoietin therapy preoperatively.
Although iron stores may be adequate, supplemental iron
and folic acid may be required. Anaemia accompanied by
thrombocytopenia or neutropenia may indicate a bone
marrow disorder, a complex autoimmune condition or
systemic disease, so seek the advice of a haematologist,
and other specialists, without delay
A classification of anaemia is given below:
• Decreased red cell production
- Haematinic deficiency:
Iron, vitamin B 12 , folic acid
- Marrow failure:
Aplastic anaemia, leukaemia, pure red cell aplasia.
• Abnormal red cell maturation
- Myelodysplasia
- Sideroblastic (Greek sideros = iron) anaemia
• Increased red cell destruction
- Inherited haemolytic anaemia, such as sickle cell
anaemia or thalassaemia (Greek thalassa = sea)
- Acquired haemolytic anaemia:
Immune (e.g. autoimmune)
Non-immune (e.g. microangiopathic haemolytic
anaemia, disseminated intravascular coagulation)
• Effects of disease in other organs
Anaemia of chronic disorder; renal, endocrine, liver
disease.
Examination of red cell indices provides important clues
to the cause of anaemia. The following alterations in red
cell indices offer a clue to the cause of anaemia.
• Lowered mean cell volume (MCV), mean cell haemoglobin
(MCH)
- Iron deficiency
- Thalassaemia trait
- Homozygous thalassaemia
- Hyperthyroidism
• Raised MCV
- Megaloblastic (Greek megalo - large) anaemia
- Hypothyroidism
- Liver disease
- Reticulocytosis
- Myelodysplasia
- Aplastic anaemia
- Paraproteinemia
- Alcohol abuse
• Normochromic normocytic
- Anaemia of chronic disease
- Renal failure
- Bone marrow infiltration
- Haemorrhage.
91
PATIENT ASSESSMENT
- ■--■-■'-■■•--■ --
A reduction in MCV and MCH (microcytic hypochromic
picture) is highly suggestive of iron deficiency. Nutritional
deficiency or very slow chronic blood loss leads to a well-
compensated anaemia of gradual onset. A raised MCV is
highly suggestive of megaloblastic anaemia and malab-
sorption (due to pernicious anaemia, coeliac disease, or
after gastrectomy) or poor dietary intake are the common-
est causes. The underlying cause of the anaemia should be
specifically treated as far as possible and elective surgery
delayed until this is achieved.
Haemoglobinopathies
These are a group of inherited disorders (autosomal recess-
ive) of haemoglobin synthesis in which affected individ-
uals (homozygotes) suffer a lifelong haemolytic anaemia.
They are the commonest human inherited disorders.
The carriers (heterozygotes) have a small degree of pro-
tection against malaria; haemoglobinopathies are there-
fore common in all parts of the world where malaria is (or
was) prevalent - southern Europe, Asia, the Far East,
Africa, South America and immigrant populations in
northern Europe and North America. Carriers are asymp-
tomatic and have a normal life expectancy, but may have
a mild degree of anaemia. Haemoglobinopathies are
divided into two types: disorders affecting haemoglobin
structure and disorders of haemoglobin synthesis. In the
structural haemoglobin variants, a single deoxyribo-
nucleic acid (DNA) base mutation leads to an amino acid
substitution in haemoglobin to give rise to a variant
haemoglobin, e.g. haemoglobin S (sickle haemoglobin,
which leads to sickle cell anaemia). The variant
haemoglobin may be functionally abnormal; thus,
haemoglobin S tends to crystallize under conditions of
low oxygen tension and this distorts red cell shape to
cause 'sickling'. The second type of haemoglobinopathy
is thalassaemia, where there is no change in the amino
acid composition of the haemoglobin molecule but there
is deficient synthesis of one of the globin chains (a or £}),
leading to imbalanced chain synthesis and anaemia.
Thalassa (Greek = sea) recognizes that the disease was
discovered in countries bordering the Mediterranean sea.
It is important to detect carriers of some haemoglo-
binopathies (e.g. sickle cell) prior to operation because
anaesthesia and hypoxia can precipitate sickling. All
patients of non-northern European origin should be
screened prior to operation, for example in the pread-
mission clinic, by haemoglobin electrophoresis and /or a
sickle solubility test. Affected individuals (homozygotes)
usually present in childhood but occasionally patients
present incidentally. Patients with sickle cell disease
(HbSS) should be managed jointly with a clinical haema-
tologist. The consultant anaesthetist performing the case
needs to know in advance of the sickle status of the
patient because special anaesthetic precautions and prac-
tices are required, including exchange transfusion prior to
major surgery such as hip replacement. This involves
venesection of the patient together with transfusion of
donor blood (6-8 units) resulting in a postexchange
haemoglobin S level of less than 30%. It can be performed
manually or using a cell separator. Minor surgery such as
dental procedures can be safely carried out without trans-
fusion in the majority of patients. Intermediate pro-
cedures such as cholecystectomy can be performed
following transfusion with 2-3 units of packed red cells
to a haemoglobin level of 10 g l" 1 (Vichinsky et al 1995).
Pay particular attention to the hydration of the patient, at
least 3 litres per day, and to oxygenation during anaes-
thesia. Patients with some haemoglobinopathies, espe-
cially HbSC disease, are at increased risk of postoperative
thrombosis, and appropriate prophylaxis with low mole-
cular weight heparin is desirable unless there are contra-
indications.
Other inherited red cell disorders
Deficiency of the red cell enzyme gIucose-6-phosphate
dehydrogenase (G6PD) is a sex-linked disorder affecting
more than 400 million people worldwide. It results in a
reduced capacity of the red cell to withstand an oxidative
stress. Patients are asymptomatic in the steady state and
have a near normal FBC, but may suffer haemolysis of red
cells in response to an oxidative challenge. Common pre-
cipitants are infection and drugs, principally antimalarials
such as primaquine, pamaquine and pentaquine but not
usually chloroquine or mefloquine, and sulphonamide
antibiotics (Mehta 1994).
Excessive bleeding
1 . Preoperative assessment should allow us to anticipate
problems. Many patients with an inherited or acquired
defect of coagulation (Table 8.2) leading to peri- and post-
operative complications cannot be detected preoperatively.
However, take a careful history, which may reveal features
such as excessive bleeding at times of previous surgery,
bleeding while brushing teeth, nose bleeds, a family of
history of bleeding disorders, spontaneous bruising, a
history of renal or liver disease and a relevant drug history.
2. Request a coagulation screen, prothrombin time (PT),
activated partial thromboplastin time (APTT) and throm-
bin time (TT) and platelet count, in any patient with a sus-
pected bleeding disorder, although disordered platelet
function can be difficult to detect. A bleeding time is the
best in vivo test of platelet function and involves a stan-
dard skin incision and timing of clot formation, provided
the tester is expert and performs it regularly. Laboratory
platelet function analyses may also be necessary.
92
HAEMATOLOGICAL ASSESSMENT AND BLOOD COMPONENT THERAPY
Table 8.2 Bleeding disorders associated with
excessive bleeding which may cause peri- or
postoperative complications
Congenital
Clotting factors
Platelets
Vessel wait
Acquired
Clotting factors
Platelets - function
Platelets - number
Vessel wall
Haemophilia A, B
von Willebrand's syndrome
Congenital platelet disorders
Hereditary haemorrhagic
telangiectasia
Drugs (anticoagulants,
antibiotics)
Liver disease
DIC (in sepsis)
Drugs (aspirin, NSAIDs)
Liver disease, renal disease,
myeloproliferative disorders,
paraproteinaemic disorders
Autoimmune
thrombocytopenia
Hypersplenism
Aplastic anaemia,
myelodysplasia
Drugs (steroids)
Vasculitis
Malnutrition
DIC, disseminated intravascular coagulation;
NSAIDs, non-steroidal anti-inflammatory drugs.
3. Ask advice from a haematologist specialising in
haemostasis before elective operation on patients with
coagulation and platelet abnormalities, since their pre-
operative management may be complex. A very common
cause of excessive intra-operative bleeding due to platelet
dysfunction is pre-operative ingestion of aspirin, clopi
dogrel, NSAIDS, or warfarin. The need for these drugs
must be assessed at the pre-operative clinic and low dose
aspirin should be stopped 10 days prior to surgery, unless
this is con train dica ted. Platelets may be required to
achieve haemostasis in bleeding patients, even with sat-
isfactory platelet counts, if they have been taking aspirin
within one week of surgery.
Anticoagulation therapy
1. The dose of oral anticoagulants such as warfarin
(named for Winconsin /llumni Research Foundation +
coumarm) is adjusted to maintain the international nor-
malized ratio (INR, which is a measure of the patient's PT
to that of a control plasma) within a therapeutic range.
The therapeutic range varies depending upon the indica-
tion for which the patient was warfarinized.
2. Heparin is a parenteral anticoagulant and may be
given in either low molecular weight or unfractionated
forms. Low molecular weight heparin (LMWH) is not
usually monitored at prophylactic doses, but at thera-
peutic doses an anti-Xa assay is required for monitoring.
Unfractionated heparin is monitored by measurement of
the ratio of the patient's APPT compared to that of control
plasma. The short half-life of unfractionated heparin
allows safer management during the perioperative period.
S™
Key point
• Always check the platelet count before starting
heparin and every second day on treatment to
detect heparin-induced thrombocytopenia
(HIT).
3. For elective surgery in patients on oral anticoagu-
lants, you must balance the risk of haemorrhage if the
INR is not reduced against the risk of thrombosis if the
INR is reduced for too long or by too great an amount. For
minor surgery (e.g. dental extraction) it is normally suffi-
cient to stop the oral anticoagulant for 2 days prior to the
procedure and restart with the usual maintenance dose
immediately afterwards. For high risk patients such as
those with prosthetic heart valves, or for patients under-
going more extensive procedures, you must stop warfarin
and substitute heparin, either subcutaneously or by con-
tinuous intravenous infusion, under close haematological
supervision to provide thrombosis prophylaxis. Patients
on warfarin who present for emergency surgery or who
have bled as a result of anticoagulant therapy may need
reversal of the anticoagulant. This can be done using
vitamin K with either a concentrate of factors II, VII, IX
and X or, if this is unavailable, fresh frozen plasma (FFP).
ARRANGING INTRAOPERATIVE BLOOD
ODMP^
Elective surgery
1. The standard red cell product is SAG-M blood, that
is, red cells suspended in an optimal additive solution of
saline, adenine, glucose and mannitol, with a citrate anti-
coagulant. Whole blood is not used in the UK, although
it is available in some other countries in Europe, and
plasma-reduced blood is available for specific multi-
transfused patients. All cellular products, such as
platelets and red cells, are leucodepleted at the blood
93
8
PATIENT ASSESSMENT
centres in the UK, and have been so since November 1999.
There is therefore no role for an in-line white cell filter in
these products. Special products/ such as blood with
extended red cell phenotyping or rare blood from the frozen
blood bank r are available after discussion with laboratory
staff and haematology consultants at the blood service.
2. Give the laboratory time to perform a 'group 7 and
antibody screen on every patient before elective surgery.
Although in most patients crossmatched blood can be
provided/ after the group and screen (G & S) in 1 hour/ the
1-4% of patients with atypical red cell alloantibodies
require extra laboratory time for antibody identification
and to obtain compatible units of blood from the blood
centre. For this reason/ grouping and saving of blood is
best performed at a preoperative clinic, even if this is
several weeks in advance, and even though a new sample
may then be required for crossmatching a day or two
before operation, depending on local hospital policy.
3. If no atypical antibodies are present, many proce-
dures can now be performed after grouping and saving
alone, blood being provided only if it is required during
or after operation. If the antibody screen has been per-
formed already and is negative, blood can be issued on an
immediate spin test taking 10 min. In some hospitals a so-
called 'electronic 7 crossmatch allows blood to be issued
without any further wet testing.
4. Most hospitals operate a standard, or maximum,
blood order schedule (SBOS/MBOS) (British Committee
for Standards in Haematology 1990). This agreed sched-
ule for blood ordering improves efficiency within the
blood bank and can also simplify the ordering process for
junior doctors. An order can be placed prior to major
vascular or hepatic operation, where there is a strong
likelihood that FFP or platelets may be required, but the
components are not usually issued until they are
required; this avoids wastage. Discuss these arrange-
ments preoperatively with a clinical haematologist and
agree the procedures for regularly recurring events.
Key point
• Blood component therapy should be given
after reviewing recent laboratory results, not
on an empirical basis.
5. Elective surgery should be undertaken on patients
with thrombocytopenia, or congenital and acquired dis-
orders of coagulation, only after careful preoperative
assessment, and under the direction of a haematologist.
6. Many patients can avoid allogeneic transfusion by
normalization of haemoglobin preoperatively, using ery-
thropoietin and iron therapy as appropriate, minimization
of intra- and postoperative blood loss, and acceptance of
a lower postoperative haemoglobin, such as 7-8 g dP 1 . A
blood loss of 1.5 litres is well tolerated by most patients
who have a normal initial blood haemoglobin, without
the need for red cell transfusion of any sort, provided they
are given adequate volume support with crystalloid and
colloids.
Preoperative autologous transfusion
There are three kinds of autologous (derived from the
same individual) blood transfusion that are practised to
varying degrees at hospitals in the UK.
1 . Intra- and postoperative cell salvage
2. Acute normovolemic haemodilution
3. Preoperative autologous deposit (PAD).
Intra- and postoperative cell salvage
A number of companies manufacture equipment that can
be used to collect shed blood from intraoperative wounds
and drains, and also postoperative drainage containers.
Some of these return the blood as collected or they may
be used to wash and process the blood to remove plasma
constituents. If large volumes of shed blood are returned
without processing, the patient may experience coagu-
lation problems that can cause further bleeding. These cell
salvage procedures have been evaluated by clinical trials
in cardiac and orthopaedic surgery. There is definite evi-
dence that salvage can reduce the proportion of patients
who receive allogeneic red cell transfusion in orthopaedic
surgery. In cardiac surgery, trials show only a slight
reduction in transfusion of allogeneic red cells. The
systems have also been used in liver surgery and liver
transplantation and are increasingly used in other major
vascular surgical procedures. Many clinicians believe
from clinical experience that patients with major surgical
blood losses do better if they are managed by reinfusing
salvaged blood. These systems should not be used for
'dirty' wounds where there is risk of infection from bowel
contents or abscesses. Great caution is also exercised over
the use of this equipment in patients with malignancy.
Acute normovolaemic haemodilution
There is some controversy over the value of this proce-
dure, in which the anaesthetist withdraws several packs
of the patient's blood in the anaesthetic room immedi-
ately before surgery, replacing the volume straight away
with crystalloid or colloid. The collected blood is then re-
infused during or immediately after the operation. The
blood must be taken into a clearly labelled blood pack
containing standard anticoagulant and should remain
94
HAEMATOLOGICAL ASSESSMENT AND BLOOD COMPONENT THERAPY
8
with the patient until it is reinfused to avoid problems of
transfusion to an inappropriate patient. Reinfusion must
be completed before the patient leaves the responsibility
of the anaesthetist- This procedure is most likely to be of
benefit where the anticipated blood loss is greater than
one litre and where the patient's haematocrit is relatively
high. The degree to which the haematocrit can be lowered
preoperatively depends on the status of the patient but
patients who can tolerate a low haematocrit are likely to
benefit most from this procedure.
Preoperative autologous deposit (PAD)
1 . It may be possible for the patient to make a preop-
erative donation of 2-A units of red cells - typically 1 unit
per week - for autologous transfusion at or after opera-
tion. This is suitable for patients undergoing major
surgery likely to require transfusion, especially if there
are red cell phenotypying problems or refusal to receive
donated blood. Directed donations from family or friends
are not recommended in the UK, primarily because of
confidence in the general safety of donor blood and
concern that coercion may inhibit voluntary withdrawal
of unsuitable donors.
2. Autologous donations may not be given by patients
with active infections, unstable angina, aortic stenosis or
severe hypertension. A haemoglobin level of > 10 g dl" 1 is
maintained with oral iron supplements. Trials have failed
to demonstrate a consistent advantage from using recom-
binant human erythropoietin (rhEPO) to accelerate
haemopoiesis. Elective orthopaedic and gynaecological
surgery are two areas where up to 20% of patients may be
suitable for autologous donation.
3. A number of issues mitigate against the wider appli-
cability of this procedure:
a. Late cancellation of surgery can lead to waste.
b. Relatively few patients are suitable for PAD because
of age, drug therapy or comorbidity.
c. Criteria for transfusion of donated units should be
identical to those for ordinary units and not be relaxed
simply because it is available.
d. Many patients become more anaemic following
PAD and the likelihood of receiving a transfusion
increases, whether autologous or allogeneic.
e. Current UK guidelines (British Committee for
Standards in Haematology, Blood Transfusion Task Force
1993) stipulate that autologous units be tested for the
same range of markers of transmissible disease as
homologous donations, which increases costs and leads
to ethical dilemmas if the results prove positive.
f. Although some risks of transfusion are reduced by
using autologous predeposit, errors in patient identifica-
tion may still occur. It is possible that bacterial contami-
nation is more likely than with standard donor blood.
g. Hospitals need to operate secure laboratory and
clinical protocols to ensure proper identification of auto-
logous units and separation from homologous donation.
h. The practice is likely to be associated with increased
cost, and benefits are difficult to quantify.
Emergency surgery
1. Patients who are clinically shocked, as from sepsis or
haemorrhage, or actively bleeding, require preoperative
clinical and laboratory assessment. If possible, stabilize the
patient prior to operation unless there is immediate access
to the operating theatre to stop the bleeding. Maintain
blood pressure, circulating volume and colloid osmotic
pressure. First priorities in treating acute blood volume
depletion are to maintain blood pressure, circulating
volume and colloid osmotic pressure and then to restore
the haemoglobin level. The appropriate initial therapy is
to give a synthetic plasma substitute and crystalloid.
2. Replace massive blood loss with red cells, FFP,
platelets and cryoprecipitate, as indicated by results of
testing for PT, APTT, TT, fibrinogen levels and platelet
count. The thromboelastogram (TEG), which gives a
global assessment of clotting efficiency, is used routinely
in some hospitals. Maintain normothermia by transfusing
all blood and fluids through a warming device. Even mild
hypothermia can contribute to coagulopathy.
3. In an extreme emergency you may give uncross-
matched group O RhD negative blood, 'flying squad
blood', immediately. As soon as a sample from the
patient reaches the laboratory, group-compatible uncross-
matched blood may be issued within approximately
10 min. It requires 45-60 min for a full crossmatch. A
retrospective crossmatch will always be performed on
any uncrossmatched units transfused in an emergency.
BLOODj:OMP^
1, The supply of blood components in the UK is based
on unpaid volunteer donors. Over 99% of donor blood is
separated into components, predominantly red cells in
additive solution, fresh frozen plasma (FFP), platelets and
cryoprecipitate. Cryosupernatant and buffy coats are also
produced (Table 8.3). The collection, testing and process-
ing of blood products is organised within the UK by the
National Blood Service under the aegis of the National
Blood Authority (NBA). Fractionated plasma products,
produced by the Bio Products Laboratory (BPL) section of
the NBA, are now produced entirely from imported USA
plasma. This is because of fears about potential transmis-
sion of variant Creutzfeldt-Jakob disease (vCJD) through
the British blood supply. The fractionation process is used
to produce intravenous immunglobulin (IVIg), albumin,
specific immunglobulins and other products.
95
PATIENT ASSESSMENT
Table 8.3 Blood constituents available for clinical
use
Whole blood*
Blood components*
Red cells - plasma reduced
- leucocyte poor
- frozen
- phenotyped
Platelets
White cells (buffy coat)
Fresh frozen plasma
Cryoprecipitate
Plasma products
Human albumin solution
Coagulation factor concentrate
Immunoglobulin
- specific
*These products are
- standard human
not heat treated, and all may
transmit microbial infection.
2. The hospital transfusion laboratory is concerned
with grouping and antibody screening of patient samples,
compatibility testing and issuing of appropriate compo-
nents, together with running an appropriate and accurate
documentation system. Remember that, unlike the rest of
pathology, the transfusion laboratory, under the direction
of its consultant haematologist, is offering a therapy for
patients, not merely a testing service. Seek advice regard-
ing the appropriate use of therapeutic components from
the haematologist in change.
3. All the functions of the hospital transfusion laboratory
require regulation and monitoring and both internal and
external quality assurance schemes are performed regu-
larly. Hospital laboratories have standard operating proce-
dures for all the laboratory work carried out within them.
Hospitals are also required by the Department of Health,
via the Better Blood Transfusion initiative, to have a set of
protocols and guidelines in place which are issued to all
medical staff, detailing the range of components available
together with procedures and indications for their use. The
standard blood-ordering schedule is one of these, as men-
tioned above. The Hospital Transfusion Committee (HTC)
provides a forum whereby the clinical users of blood com-
ponents can meet with the laboratory staff, the haematolo-
gist in charge of transfusion and the local transfusion
specialists from the blood centre. The responsibilities of
such a committee are to organize audit so that activity can
be assessed against protocols, to provide information on
use of resources, to monitor inappropriate use and adverse
effects of transfusion and to provide a mechanism whereby
the audit loop can be completed. Plans for education and
training in blood transfusion may be drawn up by the HTC
along with new protocols and initiatives to improve blood
transfusion practice within the hospital. The HTC is
directly accountable to the Chief Executive and once again
this pattern of responsibility is now formally expected and
monitored by the Department of Health. Serious adverse
events in transfusion are reported to SHOT (Serious
Hazards of Transfusion), which is a national reporting body
that collates anonymized data nationwide on serious
adverse events. An annual report is brought out and actions
are drawn up to try and improve transfusion practice in
hospitals nationwide. In the 5 years since this scheme
began, nearly 70% of reports to SHOT have been in the
category of 'incorrect blood component transfused 7 .
Blood grouping and compatibility testing
Red cells carry antigens, which are typically glycoproteins
or glycolipids attached to the red cell membrane.
Antibodies to the ABO antigens are naturally occurring.
Antibodies to other red cell antigens, such as the Rh
group (CDEce), Kell, Duffy and Kidd, appear only after
sensitization by transfusion or pregnancy and may cause
haemolytic transfusion reactions and haemolytic disease
of the fetus and newborn.
1. Naturally occurring antibodies are usually IgM anti-
bodies but may be IgG and are found in individuals who
have never been transfused with red cells or who have
not been pregnant with a fetus carrying the relevant red
cell antigen. They are believed to be produced in response
to exposure to substances that are found within the en-
vironment, including the diet, which have similar struc-
ture to red cell antigens. Naturally occurring anti-A anti-B
and anti-AB antibodies are reactive at 37°C and are com-
plement fixing antibodies which cause intravascular lysis
of ABO incompatible red cells.
2. Immune red cell antibodies are principally IgG, but
can contain an IgM and /or an IGA component and these
are formed as a result of exposure to foreign red cell anti-
gens during transfusion or pregnancy. Frequency of these
immune red cell alloantibodies is determined by the fre-
quency of the antigen in the population and its immuno-
genicity Of these D is by far the most immunogenic,
followed by Kell (K) and c The concentration of the anti-
bodies decreases over time if the individual is not
exposed to further antigenic stimulus and they may
become undetectable in the laboratory.
!••
Key point
• Report to the clinical haematologists and
transfusion laboratory staff any patient with a
history of a previous red cell alloantibody.
96
HAEMATOLOGICAL ASSESSMENT AND BLOOD COMPONENT THERAPY
8
3. In the blood transfusion laboratory all samples sent
for "group and screen' or 'group and save' have the ABO
and RhD group determined using monoclonal antibodies,
which cause direct agglutination of red cells at room tem-
perature if the relevant antigen is present on those red cells.
A screen for atypical red cell alloantibodies is performed in
which the patient's serum is incubated with reagent red
cells, usually three different ones, which between them
carry all the commonest red cell antigens. Any antibodies
present in the serum will coat the reagent red cells during
the incubation period. The red cells are then washed to
remove free antibody, and antihuman globulin (AHG) is
added to cause visual agglutination of any red cells that
are coated with antibody. This is known as the indirect
antiglobulin test (IAT) or Coombs' test. If antibodies are
detected using this test, a more extended red cell panel is
used to identify which alloantibodies are present, These
techniques may be carried out in glass tubes, in microtitre
plates or in solid phase (Diamed) columns.
ABO, Rh compatible blood may then be crossmatched,
or a G & S sample can be held until blood is required. A
lower threshold for crossmatching is necessary if a patient
has alloantibodies as this may cause delay in finding
compatible blood at short notice.
Red cell transfusion
Major indications for transfusion of red cells are bleeding,
anaemia (if severe, and the cause has been established
and cannot be treated with alternatives) and bone marrow
failure.
1. The majority of red cells issued in the UK are resus-
pended in optimum additive solution, most commonly
SAG-M (sodium chloride, adenine, glucose and manni-
tol). The blood is anticoagulated with a citrate anticoagu-
lant. The approximate volume of an SAG-M unit of red
cells is 270 ml ± 50 ml. The haematocrit is between 0.5 and
0.7. All cellular components are leucodepleted in the UK
and the white cell count per unit is less than 5 x 10 6 . There
is therefore no indication for the use of a bedside in-line
filter in the UK.
2. The blood has a shelf life of 35 days when stored
between 2°C and 6°C. It can be out of controlled storage
temperature for up to a maximum of 5 h before transfu-
sion is completed.
3. During storage the concentration of the red cell 2,3-
diphosphoglycerate (2,3-DPG) gradually falls, which
increases the oxygen affinity and reduces the amount of
oxygen the cells can deliver to tissues. Red cells in SAG-
M are not usually used for exchange transfusion or large
volume transfusion in neonates. An alternative product
using citrate phosphate dextrose and adenine (CPDA) is
used.
4. There is almost no whole blood issued to any hospi-
tal in the UK at present (less than 1 % of units are issued
as whole blood), but alternative plasma-reduced products
are sometimes available for multitransfused problem
patients.
5. Red cells matched for extended phenotype are
issued for patients who are transfusion dependent and at
risk of producing multiple red cell alloantibodies.
6. There is a bank of frozen red cells available through
the National Blood Service stored at Birmingham. These
include rare units negative for specific common antigens,
for use in patients with multiple red cell antibodies. These
are made available for particular patients after discussion
with the consultant haematologists in the National Blood
Service.
Indications
1 . For the majority of patients undergoing elective or
emergency surgery a transfusion trigger of 8 g dl" 1 is
appropriate. Patients with known cardiovascular disease,
previous myocardial infarction and the very elderly or
infirm may require a higher haemoglobin perioper-
atively. A patient undergoing operation with a normal
haemoglobin of approximately 14 g dl -1 can afford to lose
1.5 litres of blood before red cell transfusion becomes
necessary. Clearly the patient should not be allowed to
become hypovolaemic or hypotensive and the volume
lost must be replaced with colloids and crystalloid as
appropriate. Except in an emergency, patients should not
undergo operation if they are anaemic. At preoperative
clerking clinics, iron deficiency anaemia or anaemia of
chronic disease can be corrected using iron therapy or
erythropoietin as appropriate. This reduces unnecessary
use of a limited resource and exposure of patients to
potentially risky blood products.
2. A recent large randomised clinical trial in critically
ill patients demonstrated that a restrictive transfusion
policy aimed at maintaining Hb in the range 7-9 g dl -1
was at least equivalent, and possibly superior, to a liberal
policy maintaining Hb at 10—12 g dl ^. A trigger
haemoglobin of 7-8 g dl -1 is therefore appropriate even in
the critically ill, except perhaps for those with unstable
angina or acute myocardial infarction (MI). This leaves
some margin of safety over the critical level of 4-5 g dl -1 .
At this level, oxygen consumption begins to be limited by
the amount that the circulation can supply.
3. In those patients with abnormal bone marrow func-
tion from bone marrow failure resulting from drugs or
marrow infiltration, it may be less appropriate to allow the
haemoglobin to become so low; a maintenance trough
level of 9 g dl -1 may be appropriate. There is now some evi-
dence that patients receiving radiotherapy for malignancy
have better outcomes if the haemoglobin is maintained at
97
PATIENT ASSESSMENT
a normal level, 12 g dl" 1 or more, throughout the period of
radiotherapy. It relates to the effects of hypoxia on rumour
growth and therefore on the efficacy of radiotherapy.
Remember though, that this is a small group; the vast
majority of elective surgical patients do not fall into this
category.
4. As a rule of thumb, in an average-sized adult, one
unit of red cells raises the haemoglobin by 1 g dl -1 . There
is only 200 mg of bioavailable iron in a unit of red cells,
so remember that this is not an appropriate treatment
for iron deficiency anaemia. Transfusion may correct a
severely low haemoglobin in those who are symtomati-
cally anaemic, but it will not correct iron deficiency. Oral
iron replacement therapy is required for 4-6 months.
Alternatively, give a total dose infusion of iron.
Platelet transfusion
Platelet concentrates may be produced by the pooling of
platelets from four standard whole blood donations or
may be from donors who give platelets alone via an
apheresis (Greek apo = from + haireein = to take; to separ-
ate) machine, in which case only one donor's platelets are
present in each adult dose. A standard adult dose in either
case is 2.4 x 10 11 platelets, suspended in 150-200 ml of
plasma. This product has a shelf life of 5 days and is
stored at 22°C on a platelet agitator. Platelets express ABO
antigens but not Rh antigens and therefore they should be
ABO matched as far as possible. There are a small number
of red cells present in platelet concentrate and therefore
women of child-bearing age should receive RhD matched
platelets. If a RhD-negative women has to be given RhD-
positive platelets she should be given anti-D cover as
appropriate. A standard adult dose of platelets normally
raises the count by 10 x 10 9 1" 1 at 1 h posttransfusion.
Indications
1. They are most commonly used to support patients
with acute bone marrow failure, for instance after
chemotherapy or stem cell transplant. If patients requir-
ing platelet support are undergoing invasive procedures,
a count of 50 x 10 9 l -1 may be required for line insertion
and minor procedures, and a count of 80-100 x 10 9 \~ l for
major surgery.
2. Patients with platelet function disorders, whether
inherited or acquired, may have normal platelet counts
but abnormal platelet function. They may require platelet
support during or after surgery. The most common
acquired platelet function disorder results from the inges-
tion of aspirin in the 7-10 days before operation. Platelet
transfusion may be indicated for patients who have
ingested aspirin within this period and who suffer from
prolonged intra- or postoperative oozing.
3. Platelets, together with FFP and cryoprecipitate,
may need to be given for consumptive coagulopathy such
as disseminated intravascular coagulation (DIC). The
transfused blood components should be given on the
basis of laboratory coagulation parameters and platelet
counts.
4. Massive red cell transfusion may eventually produce
dilutional thrombocytopenia and require platelet transfu-
sion, controlled as far as possible from the laboratory
results.
5. Patients may require platelet support when on extra-
corporeal bypass, undergoing for example open heart
surgery, even though the platelet count is normal or near
normal, because the platelets are activated while in the
extracorporeal circuit and therefore may be ineffective in
haemostasis.
Platelets are not indicated for:
• Chronic thrombocytopenia, unless there are bleeding
problems
• Prophylatically for patients undergoing bypass
• Immune thrombocytopenic purpura, except in the case
of critical bleeding.
Platelet transfusion is contraindicated because it may
aggravate the underlying conditions in:
• Heparin-induced thrombocytopenia, which is an
autoimmune-mediated condition resulting in arterial
blood clotting
• Thrombocyte thrombocytopenic purpura.
All patients receiving prophylatic or therapeutic heparin
using unfractionated or low molecular weight heparin
should have a platelet count performed prior to com-
mencement of heparin, on the day following and every 2
days thereafter.
Key point
• Suspect heparin-induced thrombocytopenia if
there is a drop in platelet count below
100 x 10 9 1 1 and urgently seek advice from a
haematologist Amputation results in 30% of
cases. Stop heparin, use an alternative
anticoagulant.
Fresh frozen plasma (FFP)
1. FFP is prepared by centrifugation of donor whole
blood within 8 h of collection, and frozen at -30°C. It may
be stored for up to 12 months and is thawed prior to
administration, 300 ml taking approximately 20 min to
thaw. Once thawed it should be used within 2 h as there
98
HAEMATOLOGICAL ASSESSMENT AND BLOOD COMPONENT THERAPY
8
is exponential degradation of the clotting factors at room
temperature.
2. Compatibility testing is not required, but group
compatible units are used. FFP contains coagulation
factors, including the labile factors V and VIII and the
vitamin K-dependent factors II, VII, IX and X.
3. In clinical practice FFP is frequently given unnecess-
arily and, when it is indicated, not enough is given. To
correct abnormal coagulation a dose of 15 ml kg -1 is
required. In a 70 kg adult this is almost 1 litre of FFP; cor-
rected to the nearest whole bag this is three bags.
4. Standard FFP carries the same risks as red cells for
transmitting viral, bacterial and prion disease. Some
virally inactivated plasmas are now available. Solvent
detergent-treated plasma is created from pools of up to
1000 donors, which are available as Octaplas™, and non-
pooled methylene blue-treated plasma is now available
for paediatric use via the National Blood Service. Both of
these products are safer in terms of viral transmission
than standard FFP, although they are still not completely
safe and some viruses may not be inactivated. Viral inac-
tivation procedures have no effect on possible prion trans-
mission. Clotting factor levels are slightly diminished in
both products, possibility resulting in the need to use a
greater number of units per patient.
Indications
The indications for FFP transfusion are:
1. Coagulation factor replacement where there is no
concentrate available. In hospitals with an interest in
haemophilia and haemostasis the vast majority of
inherited clotting factor deficiencies are treated with
specific concentrates, with the exception of factor V
deficiency for which there is no concentrate available.
In hospitals without a specialist unit, FFP may be
used more widely for clotting factor deficiencies.
2. To correct abnormal clotting in patients with DIC or
those who have undergone massive transfusion or
cardiopulmonary bypass. In all these give FFP
guided by the coagulation results obtained from
near-patient testing, or from the central laboratory
3. To correct abnormal coagulation in patients with liver
disease and poor synthetic function. Administration
of vitamin K may also help in this situation.
4. To reverse oral anticoagulation as from, for example,
over warfarinization, if there are no concentrates
available.
5. Specifically indicated for plasma exchange in the
management of thrombotic thrombocytopenic
purpura (TTP) and haemolytic uraemic syndrome
(HUS). Cryo-poor FFP may be a superior product in
this setting.
FFP should not be used:
1. To treat hypovolaemia which can adequately be
managed using colloid and crystalloid solutions.
2. For plasma exchange except in the specific
circumstances stated above.
3. As a 'formula' replacement; for example, there is no
need to administer two bags of FFP for every 4 or
6 units of red cells transfused. Give replacement with
FFP on the basis of clotting results, or, if necessary,
for clinical indication.
4. In the management of nutritional or
immunodeficiency states.
5. In bleeding due to thrombocytopenia or
hypofibrinogenaemia, for which platelet concentrates
and cryoprecipitate, respectively, are indicated.
Cryoprecipitate
1. This is prepared from FFP by freezing and thawing
plasma and then separating the white precipitate from the
supernatant plasma. Cryoprecipitate (Greek kryos = frost)
contains half of the factor VIII, fibrinogen and fibronectin
from the donation and also the majority of the von
Willebrand factor. In common with FFP, it is stored at
-30°C for up to 12 months. As the volume of each pack is
only 10-20 ml, the product thaws very quickly and can be
ordered when it is about to be given. Also, like FFP, the
effectiveness of the product decreases rapidly once it has
been thawed. A standard adult dose is 10 units, which
should be ABO compatible but not crossmatched.
2. Cryoprecipiate is indicated when replacement of fib-
rinogen is required in those with congenital or acquired
hypofibrinogenaemic states. In DIC, if the fibrinogen
drops below 0.8 g l" 1 , give cryoprecipitate. Remember to
request a fibrinogen level in patients with massive bleed-
ing or DIC as this is not automatically performed with a
clotting screen in most laboratories. Cryoprecipitate was
formerly the mainstay of management of patients with
von Willebrand' s disease but a concentrate is now avail-
able for this condition at many centres.
Plasma products
These are produced by a fractionation process and are
derived from pooled human plasma. The product is
concentrated and sterilized and the risk of infection is
markedly reduced. However, there is still a theoretical
risk that they could transmit prion proteins, which are
implicated as a transmissible cause of new variant
Creutzfeldt-Jakob disease (nvCJD). For this reason all
plasma for fractionation in the UK is now imported from
the United States, where it is taken from accredited
donors. The processing still takes place in the UK.
99
PATIENT ASSESSMENT
Albumin solution
This is usually available as 20 g albumin in 400 ml, as a 5%
solution, or 100 ml of 20% solution. Each unit also contains
sodium 130-150 mmol 1 _1 plus other plasma proteins and
stabilizer. The main indications for albumin are hypo-
proteinaemia with nephrotic syndrome (20%) and chronic
liver disease (20%) and acute volume replacement (5%), for
example, for plasma exchange. It may also be used in
hypoproteinaemia following burns after the first 24 h. There
is no evidence that albumin solutions are necessary to
restore circulatory volume following haemorrhage, shock
or multiple organ failure; colloid and crystalloid solutions
are equally efficacious, cheaper and probably safer.
Coagulation factor concentrates
1. These are largely used in patients with congenital
bleeding disorders, and recombinant factor VIII and
factor IX are now widely used. Concentrates are also
available, manufactured from pooled fractionated human
plasma, sourced from outside the UK.
2. Prothrombin complex concentrate contains factors
IX, X and II and is used to treat bleeding complications in
inherited deficiencies of these factors. When given with
vitamin K, it is also used to treat oral anticoagulant over-
dose, and in severe liver failure. Its use carries a risk of
provoking thrombosis and DIC.
3. Other concentrates include the naturally occurring
anticoagulant factors protein C, antithrombin (see below)
and factors VII, XI and XIII; they are used in correspond-
ing congenital deficiencies. FEIBA (factor VIII bypassing
activity concentrate) is used in patients with inhibitors to
factor VIII, as is recombinant factor Vila in some circum-
stances. Recombinant factor Vila has also recently been
used experimentally for management of massive bleeding
that is not responding to other clotting concentrates and
platelet infusions. There is now a substantial body of anec-
dotal evidence that this may be effective and life saving in
some cases. Recombinant factor Vila has significant pro-
thrombotic effects; it is extremely expensive and should
only be used under the guidance of a haematologist expe-
rienced in its use. A fibrinogen concentrate is now available
for severe forms of hypofibrinogenaemia, both congenital
and acquired, and fibrin sealants are also available.
Immunoglobulins
These are prepared from pooled donor plasma by fraction-
ation and sterile filtration. Specific immunoglobulins
include hepatitis B and herpes zoster and can provide
passive immune protection. Standard human immunoglo-
bulin for intramuscular injection is used for prophylaxis
against hepatitis A, rubella and measles, whereas hyper-
immune globulin is prepared from donors with high titres
of the relevant antibodies for prophylaxis of tetanus,
hepatitis A, diphtheria, rabies, mumps, measles, rubella,
cytomegalovirus and Pseudomonas infections. Intravenous
immunoglobulin is used as replacement therapy in
patients with congenital or acquired immune deficiency
and in autoimmune disorders (e.g. idiopathic thrombo-
cytopenic purpura).
Plasma substitutes
These include products based on hydroxyethyl starch
(HES), dextran (a branch-chained polysaccharide com-
posed of glucose units) and modified gelatin. Such com-
ponents remain in the circulation longer than crystalloid
solutions - up to 6 h for modified gelatin and up to 24 h
for some high molecular weight starch-based products.
Other advantages are that they are relatively non- toxic,
inexpensive, can be stored at room temperature, do not
require compatibility testing and do not transmit infec-
tion. Adverse effects include anaphylaxis, fever and rash,
such effects being more frequent with starch-based prod-
ucts. Dextran can also impair coagulation and platelet
function and can interfere with compatibility testing.
Key point
• Take a blood sample for crossmatching before
administering dextran.
The maximum dose of synthetic plasma expanders is
approximately 20-30 ml kg -1 . Patients receiving larger
volumes or with significant evidence of other organ
failure, such as pulmonary or renal disease, or a bleeding
diathesis, may be given albumin.
ADVERSE CONSEQUENCES OF BLOOD
TRANSFUSION
^^^^^^^^li^^^^i^^^'^^^^^.
■f&^&&tfift&i&L
In general, transfusion of blood and products is a safe and
effective mode of treatment.
1. The safe administration of blood components is a
deceptively complex process involving phlebotomists,
clerical staff, junior doctors, porters and nurses as well
as transfusion laboratory staff. A survey in the UK
(McClelland & Phillips 1994) suggests that a 'wrong blood
in patient' incident occurs approximately once per 30 000
units of red cells transfused. By far the commonest cause
is a failure at the bedside of pretransfusion identity check-
ing procedures, either at the time of phlebotomy or while
setting up the actual transfusion.
100
HAEMATOLOGICAL ASSESSMENT AND BLOOD COMPONENT THERAPY
8
Key point
• Pay rigorous attention to all administrative and
clerical aspects of blood component therapy;
they are overwhelmingly the commonest cause
of fatal errors.
2. In the UK all hospitals participate in the SHOT
(Serious Hazards of Transfusion) reporting scheme which
allows for anonymized reporting of serious transfusion
events to a centralized data collecting body. Cumulative
data from the past 5 years has shown that 'Incorrect blood
component transfused' is by far the commonest reported
event, with nearly 70% of all reports coming into this cat-
egory. Conversely, the most feared and well-publicized
complication, that of infectious disease transmission, is
one of the very least common categories, with only 1-2%
of cases. It is now mandatory for all hospitals to partici-
pate in the SHOT scheme as set out in the Department of
Health circular Better Blood Transfusion, published in July
2002 (Table 8.4).
Immune complications
ABO-incompatible red cell transfusions lead to life-
threatening intravascular haemolysis of transfused cells,
manifesting as fever, rigors, haemoglobinuria, hypoten-
sion and renal failure (immediate haemolytic transfusion
reaction (HTR)). In the anaesthetized patient, the only
signs may be persistent hypotension and unexplained
oozing from the wound.
Atypical antibodies arising from previous transfusions
or pregnancy may cause intravascular haemolysis but
more commonly lead to extra vascular haemolysis in liver
and spleen and may be delayed for 1-3 weeks (delayed
HTR). Typical manifestations are jaundice, progressive
anaemia, fever, arthralgia and myalgia. Diagnosis is easily
established by a positive direct antiglobulin test (DAT)
and a positive antibody screen. Non-haemolytic febrile
transfusion reaction (NHFTR) usually occurs within hours
of transfusion in multitransfused patients with antibodies
against HLA antigens or granulocyte-specific antibodies.
The reaction is due to pyrogens released from granulo-
cytes damaged by complement in an antigen-antibody
reaction. It presents as a rise in temperature, with flushing,
palpitations and tachycardia, followed by headache and
rigors. Hypersensitivity reactions to plasma components
may cause urticaria, wheezing, facial oedema and pyrexia,
but can cause anaphylactic shock, for example, in patients
with congenital IgA deficiency who have antiTgA anti-
bodies following previous sensitization,
Treatment
Stop the transfusion immediately in all cases except for
the appearance of a mild pyrexia in a multiply transfused
patient. Check clerical details and send samples from the
donor unit and recipient for analysis for compatibility
and haemolysis. Have the recipient serum analysed for
the presence of atypical red cell leucocyte HLA and
plasma protein antibodies. Treat severe haemolytic trans-
fusion reactions with support care to maintain blood
pressure and renal function, to promote diuresis and
treat shock. Intravenous steroids and antihistamines
may be needed, with the use of adrenaline (epinephrine)
in severe cases. Manage NHFTR by administering
antipyretics.
Table 8.4
Hazards of transfusion
Non-immune complications
Immune complications
Acute
Hypothermia
Febrile non-haemolytic transfusion reaction
Hyperkalemia (IK 4 )
Acute haemolytic reaction (ABO incompatibility)
Hypocakaemia (lCa 2+ )
Allergic reactions (urticarial or anaphylactic)
Air embolism
TftALl (transfusion-related acute lung injury)
Bacterial (endotoxic) shock
Delayed
HIV
Delayed haemolytic transfusion reaction (due to
Hepatitis C
red cell alloantibodies)
Hepatitis B
Posttransfusion purpura
CMV
Transfusion-associated graft versus host disease
Parvovirus B19
Immune modulation
Others: e.g.: hepatitis A, ma
laria, brucellosis,
Syphilis, trypanosomiasis,
vCJD?
101
PATIENT ASSESSMENT
Transmission of infection
1. Blood transfusion is an important mode of trans-
mission of a range of viral, bacterial and protozoal infec-
tions. There is also a theoretical risk of transmitting
infections mediated by prion proteins such as new variant
CJD (Flanagan & Barbara 1996, 1998), although no proven
or even probable instances of such transmissions have
ever been identified. However, concern has been raised
by a study in which one (of 19) asymptomatic sheep, 318
days after being given 5 g of brain infected with bovine
spongiform encephalopathy (BSE) in the feed, appeared
to transmit BSE to a second sheep via a 400 ml venous
transfusion (Brown 2000, Houston et al 2000). A recent
update on this study suggests that up to four sheep may
now be suffering from transfusion transmitted prion
disease. Therefore, until definitive evidence becomes
available, steps have been taken to reduce the risk of
transfusion as a possible secondary route of transmission
of vQD (Brown et al 2001):
• In UK from November 1999:
- ban on using UK plasma for manufacture of frac-
tionated products (e.g. albumin, clotting factors,
IVIg)
- leucodepletion of all blood, platelets, FFP, cryopre-
cipitate (as leucocytes believed to play key role in
vCJD pathogenesis)
• In other countries (e.g. USA, Canada, New Zealand
etc.):
- exclusion as blood donors of people who have
lived in the UK for >6 months between 1980 and 1996.
2. It should be emphasized that the safety of blood
components and fractionated plasma products has
improved greatly in recent years. Bacterial infections can
occur through failure of sterile technique at the time of
collection, commonly by organisms such as Staphylococcus
aureus or Staph, epidermidis, or bacteraemia in the donor -
especially if organisms such as Yersinia, which can survive
at 4°C, are incriminated.
3. There are more fatalities per annum from bacterial
or endotoxic complications, usually relating to platelets,
than from viral transmissions. Donors at risk of
malaria are not eligible to donate, but a malarial anti-
body test is likely to be available for screening at-risk
donors in the near future. Transmission of syphilis is
now very rare.
Viral infection
Transmission of viruses may occur in spite of mandatory
screening because: serological tests may not have had
time to become positive in a potentially infectious indi-
vidual; the virus may not have been identified; or the
most sensitive serological tests may not be routinely
performed. The risk of transmission is much lower,
although still present, for those blood products that have
undergone a manufacturing and sterilization process
(Table 8.5).
Key point
The perceived risk of viral transmission is high:
the actual risk in the UK is very low - less than
1 in 4 million for HIV and 1 in 3 million for
hepatitis C (Williamson et al 1996).
Table 8.5 Risk of virus transmission
Risk factor
Acute haemolytk reactions
Hepatitis B
Hepatitis C
HIV
Bacterial contamination of red cell concentrates
Estimated frequency
per unit transfused
1 in 250 GOO to 1 in 1 000 000
1 in 100 000 to 1 in 400 000*
1 in 3 000 000'
1 in 4 000 000
1 in S00 000
Deaths per
million units
0.67
<05
<0.5
<0,5
<0 25
*Data on viral markers from Kate Soldan, National Blood Servite/CPHL
1 Data on hepatitis C markers from Dr Pat Hewitt and Dr John Barbara, National Blood Service.
Adapted from British Committee for Standards in Haematoiogy, Blood Transfusion Task Force 2001 Guidelines for
the Clinical Use of Red Cell Transfusions, British Journal of Haematology 113: 24-31
102
HAEMATOLOGICAL ASSESSMENT AND BLOOD COMPONENT THERAPY
Other complications
1 . There is increasing evidence that transfusion of blood
components can cause immunosuppression in the recipi-
ent. This may lead to earlier relapse or recurrence of malig-
nant disease after surgical removal of malignant tumours
(shortened disease-free interval), as well as an increased
incidence of postoperative infection. These effects are
probably due to defective cell-mediated immunity and are
reduced by giving leucocyte-depleted components.
2. Circulatory overload may result from the infusion of
large volumes in patients with incipient heart failure. Iron
overload occurs in patients who have received repeated
red cell transfusions and these patients require iron chela-
tion therapy (Greek chele - claw; attaching the iron to an
agent that renders it harmless).
3. Graft versus host disease may be caused by transfu-
sion of T lymphocytes into severely immunosuppressed
hosts, and cellular components should be irradiated prior
to transfusion to severely immunodeficient patients.
INTRAOPERATIVE ASSESSMENT
1. Rapid bleeding confined to one site is almost always
a technical problem. Suspect haemostatic failure in a high
risk patient with multiple sites of bleeding, or if the
pattern of bleeding is unusual; confirm it with appropri-
ate laboratory tests.
2. The following tests are useful in assessing the degree
of blood loss and should serve as a guide for determining
the need for replacement therapy;
• Oxygen-carrying capacity of blood
- haemoglobin concentration
- pulse oximetry
• Haemostatic function
- coagulation screen:
prothrombin time (PT)
activated partial thromboplastin time (APTT)
thrombin time (TT)
- platelet count
- fibrinogen level
- thromboelastography.
3. Quantification of intraoperative blood loss is impre-
cise. Confirm clinical evaluation with laboratory tests
(Table 8.6), many of which cannot be performed outside
the main laboratory. Thromboelastography is a useful and
rapid test producing a graphical record of in vitro blood
clot formation and dissolution; it provides a global test of
coagulation and fibrinolysis which can be performed
rapidly within the operating suite in high risk patients.
4. There has been a recent resurgence in other forms
of near-patient testing, in particular in coagulometers,
which are becoming available at the bedside in intensive
care units, operating theatres, high dependency units and
obstetric units, and also in accident and emergency units.
These provide a 5 min turnaround time for PT and APPT,
instead of over an hour when samples are sent to the
central laboratory. The availability of a Hemacue for rapid
haemoglobin results has also improved management of
the bleeding patient in these sites.
Intraoperative autologous transfusion
1. Acute normovolemic haemodilution (ANH) involves
removal of 1-2 units of whole blood during induction of
anaesthesia, with replacement by crystalloid, reducing the
haematocrit to 25-30%. Operation is usually well tolerated,
the collected blood can be returned later during the oper-
ation, and there is no need to undertake virological testing
of the unit (Williamson 1994).
2. Salvage of blood lost during an operation (British
Committee for Standards in Haematology, Blood
Transfusion Task Force 1997) is accomplished using a
simple device such as Solcotrans, or a cell saver such as
Haemonetics, Dideco or Fresenius.
Table 8.6 Results of laboratory tests as an aid in differential diagnosis of excessive bleeding
Cause of bleeding Laboratory test
PT APTT TT without protamine TT with protamine
Platelet count
Loss of platelets
Lack of coagulation factors
Excess of heparin
Hyperfibrinolysis
DIC
Massive blood transfusion
Vitamin K deficiency
N
N
N
TT
TT
N
T
TT
T
T
T
TT
TT
TT
TT
t
T
N
"
T
N
N
N
N
TT
TT
N
N
N, normal; J T, markedly raised; T p mildly raised; ii, markedly decreased; I, mildly decreased.
U
Nor I
N or J^
Norl
u
i
N
103
PATIENT ASSESSMENT
3. Blood shed into the thoracic or abdominal cavity is
aspirated and mixed with anticoagulant. It can then be
returned to the patient (Solcotrans), or the red cells can be
washed, suspended in saline and transfused to the
patient (cell savers). The use of a cell saver may con-
siderably reduce the number of units required for transfu-
sion. Contraindications to using the blood salvage
procedure are exposure of blood to a site of infection or
the possibility of contamination with malignant cells.
Postoperative blood lost into drains can also be salvaged
using the cell saver.
Methods of reducing intraoperative blood
loss
Meticulous surgical technique clearly plays a major role,
but there is increasing interest in the use of pharmaco-
logical agents to improve haemostasis. Desmopressin
(DDAVP) improves platelet function by increasing
plasma concentrations of von Willebrand factor, but has
not been convincingly shown to reduce blood loss in
cardiac surgery. Aprotinin is a serine protease inhibitor
which inhibits fibrinolysis and has been shown to
reduce blood loss and operative morbidity in cardiac
surgery (particularly in repeat procedures) and major
hepatic surgery such as liver transplantation (Hunt
1991).
2. Acidosis in the patient with severe renal or liver
disease may be aggravated by the low pH of stored blood.
3. Failure of haemostasis manifests as local oozing and,
infrequently, as a generalized bleeding tendency due to
the lack of coagulation factors and platelets in stored
blood. Laboratory assessment is essential (see above). FFP
(15 ml kg 1 ) corrects the abnormalities of coagulation and
may need to be given without the benefit of laboratory
results in an emergency if 10 units or more of red cells
have been given. Platelet transfusion may be required
when the platelet count is lower than 50 x 10 9 H or to
maintain a count at 80 x 10 9 1" 1 if the patient is bleeding.
4. Hypothermia contributes to failure of haemostasis,
as the enzymatic clotting cascade functions best at 37°C.
Patients receiving large quantities of red cells, colloids
and crystalloids become hypothermic and their clotting is
suboptimal. Anticipate this problem, as clotting tests from
the laboratory may be normalized by being performed at
37°C in vitro.
Key point
Avoid hypothermia by using a blood warmer
and fluid warmer, and keeping the patient as
warm as possible.
Special situations
Massive blood transfusion
This is denned as transfusion of a volume greater than the
recipient's blood volume in less than 24 h. Standard red
cell concentrates in SAG-M can be transfused rapidly
using a pressure infuser or a pump, and a blood warmer
prevents the patient developing hypothermia. FFP, cryo-
precipitate and platelet concentrates of the same blood
group as the red cells may also be required. They should
be given on the basis of clotting screens, fibrinogen levels
and platelet counts as far as possible.
Complications include:
1. Cardiac abnormalities such as ventricular extra-
systoles, ventricular fibrillation (rarely) and cardiac arrest
from the combined effects of low temperature, high pot-
assium concentration and excess citrate with low calcium
concentration. They can be prevented by using a blood
warmer and a slower rate of transfusion, particularly in
patients with hepatic or renal failure. Routine adminis-
tration of calcium gluconate is unnecessary and may even
be dangerous unless the ionized calcium concentration in
the plasma can be monitored.
5. Adult respiratory distress syndrome (ARDS), also
called non-cardiogenic pulmonary oedema, occurs in
severely ill patients after major trauma and /or surgery.
Clinical features include progressive respiratory distress,
decreased lung compliance, acute hypoxaemia and diffuse
radiographic opacification of the lungs. The mortality is
high; post-mortem studies show widespread macroscopic
and microscopic thrombosis in the pulmonary arteries.
Local DIC, microvascular fluid leakage and embolization
of leucocyte aggregates and microaggragates from stored
blood all contribute to pathogenesis. Management consists
of stopping the transfusion, administering corticosteroids
and providing supportive treatment to combat pulmonary
oedema and hypoxia, by administering oxygen and giving
positive pressure ventilation.
Transfusion in open heart surgery
This requires cardiopulmonary bypass (CPB) for main-
taining the circulation with oxygentated blood. In adults,
blood is not required for priming of the heart-lung
machine, but it is needed in neonates and small children.
Usually 4 units of blood, ideally less than 5 days old, are
initially crossmatched, or 6-8 units for repeat procedures.
104
HAEMATOLOGICAL ASSESSMENT AND BLOOD COMPONENT THERAPY
8
It is unnecessary to use albumin solutions, either for
priming the heart-lung machine or postoperatively.
Bleeding associated with CPB results from activation
and loss of platelets and coagulation factors in the extra-
corporeal circulation, failure of heparin neutralization by
the first dose of protamine, activation of fibrinolysis in the
oxygenator and pump and /or DIC in patients with poor
cardiac output and long perfusion times.
Management requires:
• Administration of 1-2 pools of platelet concentrate
when the platelet count is less than 30 x 10 9 1" 1
• Transfusion of 15 ml kg" 1 of FFP to correct the loss of
coagulation factors
• Neutralization of excess heparin by protamine (1 mg
of protamine neutralizes approximately 100 units of
heparin)
• Administration of tranexamic acid, or a similar anti-
fibrinolytic agent, when hyperfibrinolysis is confirmed
by laboratory testing
• Treatment of DIC, in the first instance by correcting the
underlying cause, such as poor perfusion, oligaemic
shock, acidosis or infection, and then by transfusing
FFP and platelet concentrate, as required.
Prostatic surgery
This may be followed by excessive urinary bleeding, the
result of local fibrinolysis related to the release of high
concentrations of urokinase. Antifibrinolytic agents,
which include e-aminocaproic acid (EACA) and tranex-
amic acid, are often helpful in reducing clot dissolution,
but use them cautiously, as fibrinolytic inhibition can lead
to ureteric obstruction, caused by clot formation, in
patients with upper urinary tract bleeding. Patients
undergoing prostatic surgery are frequently the same
patients who are taking low dose aspirin prophylactically
to reduce the risks of coronary artery disease and stroke;
determine preoperatively if it can safely be stopped.
Following prostate surgery, bleeding can be extreme if
aspirin intake has resulted in platelet dysfunction.
Liver disease
This warrants special mention as the liver is an important
site of manufacture of the components as well as the regu-
latory factors of the coagulation and fibrinolytic pathways
(Mehta & Mclntyre 1998). Vitamin K is required for
hepatic synthesis of the coagulation factors II, VII, IX and
X, as well as the coagulation inhibitors protein C and S.
Impaired vitamin K absorption can occur in biliary
obstruction, so give 10 mg vitamin K by intramuscular
injection preoperatively. The liver is also the site of manu-
facture of factor V and fibrinogen (factor I), the regulatory
factors antithrombin and a 2 -antiplasmin. In addition,
defects of both platelet function and number, such as
thrombocytopenia due to complicating Hypersplenism, can
occur. These patients are at increased risk of DIC and renal
failure, and require assessment by a gastroenterologist/
hepatologist as well as a haematologist (see Chs 6, 15).
POST-OPERATIVE ASSESSMENT
£^^?§?£^-:^^
l->;v£VS^>^
1. Anaemia, coagulopathy and excessive bleeding in
the immediate postoperative period are often the result of
the operation or its complications. Continue blood com-
ponent therapy that was commenced intraoperatively for
the management of special situations, adhering to the
same transfusion triggers for all components that were
used intraoperatively (see above).
2. Patients with excessive bleeding and clinical evi-
dence of haemostatic failure require laboratory assess-
ment (Table 8.6). The trauma of operation triggers both
the coagulation and fibrinolytic pathways and places
patients at increased risk of DIC. Do not routinely use red
cell transfusions to correct postoperative anaemia, unless
the haemoglobin falls to below 8 g dl _1 or is excessively
symptomatic, as this practice has not been shown to
improve wound healing or aid surgical recovery.
Recovery of haemoglobin to normal levels may result
from routinely giving iron and folic acid supplements
after operation. Thromboprophylaxis is an important
aspect of postoperative care (see Ch. 34).
FUTURE DIRECTIONS
^i$y;gftz!&&ti$t&'iZgff&.
The field of transfusion medicine is rapidly developing
and there is increasing awareness of the risks of hom-
ologous blood (Greek homos - the same; from the same
species. Not autologous, Greek autos - self.). The advent
of recombinant DNA technology has already led to use
of recombinant erythropoietin, but granulocyte and
granulocyte-monocyte colony stimulating factors are in
routine use to elevate the white cell count in leucopenic
patients. Synthetic oxygen carriers ('artificial blood")
have been under development for many years (Ogden &
MacDonald 1995). Perfluorocarbons dissolve oxygen but
function only in high concentrations of ambient oxygen
and are useful only for short-term perfusion in intensive
care unit situations, such as following coronary angio-
plasty. Recombinant haemoglobin solutions and liposo-
mal haemoglobin are under active development.
105
PATIENT ASSESSMENT
Summary
• Do you recognize the need for
preoperative haematological assessment
to identify those who are already anaemic,
requiring investigation and treatment
before operation? You may also detect
inherited or acquired factors, such as
anaemia, haemoglobinopathy, excessive
bleeding tendency, affecting outcome of
surgery and anaesthesia.
• Are you aware of the available range of
blood components and plasma products
for intra- and postoperative use, their
specific indications and associated risks?
• What are the benefits of the increasingly
used intraoperative cell salvage and
autologous transfusion?
• Do you accept that administrative and
clerical failures dwarf the perceived risks
of transmitting infection?
• Do you appreciate the need to seek early
advice from the clinical and scientific
haematology staff on perioperative care of
patients with inherited or acquired
haematological conditions, and also in
special situations, such as massive
transfusion?
• Are you aware of written policies and
procedures in your institution governing
the ordering, prescription, administration
and documentation of blood components
and plasma product therapy?
References
British Committee for Standards in Haematology 1990
Guidelines for implementation of a maximum surgical blood
order schedule. Clinical and Laboratory Haematology
12: 321-327
British Committee for Standards in Haematology, Blood
Transfusion Task Force 1993 Guidelines for autologous
transfusion. 1. Pre-operative autologous donation.
Transfusion Medicine 3: 307-316
British Committee for Standards in Haematology Blood
Transfusion Task Force 1997 Guidelines for autologous
transfusion. II. Peri-operative haemodilution and cell salvage.
British Journal of Anaesthesia 78: 768-771
Brown P 2000 BSE and transmission through blood. Lancet
356: 955-956
Brown P, Will RG, Bradley R, Asher DM, Detwiler L 2001
Bovine spongiform encephalopathy and variant
Creutzfeldt-Jakob disease: background, evolution and
current concerns. Emerging Infectious Diseases 7: 6-16
Flanagan P, Barbara J 1996 Prion disease and blood transfusion.
Transfusion Medicine 6: 213-215
Flanagan P, Barbara J 1998 Blood transfusion the risk: protecting
against the unknown. BMJ 316: 717-718
Houston F, Foster JD, Chong A, Hunter N, Bostock CJ 2000
Transmission of BSE by blood transfusion in a sheep. Lancet
356: 999-1000
Hunt BJ 1991 Modifying peri-operative blood loss. Blood
Reviews 5: 168-176
McClelland DBL, Phillips P 1994 Errors in blood transfusion in
Britain: survey of hospital haematology departments. BMJ
308: 1205-1206
Mehta AB 1994 Glucose-6-phosphate dehydrogenase deficiency
Prescribers Journal 34: 178-182
Mehta AB, Mclntyre N 1998 Haematological changes in liver
disease. Trends in Experimental and Clinical Medicine
8: 8-25
Ogden JE, MacDonald SL 1995 Haemoglobin based red cell
substitutes: current status. Vox Sanguinis 69: 302-308
Vichinsky EF, Haberkern CM, Neumayr L et al 1995 A
comparison of conservative and aggressive transfusion
regimens in the peri-operative management of sickle cell
disease. New England Journal of Medicine 333: 206-213
Williamson L 1994 Homologous blood transfusion: the risks
and alternatives. British Journal of Haematology 88: 451^458
Williamson LM, Heptonstall J, Soldan K 1996 A SHOT in the
arm for safer blood transfusion. BMJ 313: 1221-1222
Further reading
Asher D, Atterbury CLJ, Chapman C et al 2002 SHOT Report
2000-2001. Serious Hazards of Transfusion Steering Group,
London
Contreras M (ed.) 1998 ABC of transfusion, 3rd edn. British
Medical Journal, London
McClelland DBL (ed.) 1995 Clinical Resources and Audit
Group: optimal use of donor blood. Scottish Office,
Edinburgh
McClelland DBL (ed.) 2001 Handbook of transfusion medicine,
3rd edn. HMSO, London
Mintz P (ed.) 1999 Transfusion therapy: clinical principles and
practice. American Association of Blood Banks, Virginia
Regan F, Taylor C (2002) Recent developments in transfusion
medicine. BMJ 325: 143-147
Useful link
www.doh.gov.uk/publications/coinh.html
transfusion: HSC 2002/009
Better blood
106
Fluid, electrolyte and
acid-base balance
W. Aveling, M. A. Hamilton
w
Objectives
To understand:
• The physiology of fluid distribution
throughout the body
• Methods of detecting hypovolaemia
• Managing fluid balance
• Principles of acid-base balance
• Interpretation of arterial blood gas results.
INTRODUCTION
gastrointestinal tract, the cerebrospinal fluid (CSF) and
aqueous humour). Water associated with bone and dense
connective tissue, which is less readily exchangeable, is of
much less importance. The partitioning of the total body
water (TBW) with average values for a 70 kg male, who
would contain 42 litres of water, is shown in Figure 9.1
{Edelman & Leibman 1959).
To understand fluid balance you need to know from
which compartment or compartments fluid is being lost
in various situations, and in which compartments fluids
will end up when administered to the patient. For practi-
cal purposes you need only consider the plasma, the
interstitial space, the intracellular space and the barriers
between them.
To be able to manage the surgical patient optimally you
must ensure that all tissues are perfused with oxygenated
blood throughout the course of the operation and the
postoperative recovery period. To do this well you need
to understand the basics of fluid balance in the healthy
person and then be able to apply this knowledge, along
with that of basic physiology, to your patient. Understand
the results provided by both arterial blood gas analysis
and modern monitoring systems, including their limita-
tions, in order to achieve optimal tissue perfusion. This
has been shown to result in reduced mortality, morbidity
and length of hospital stay.
FUJIDCOiy^^
Every medical student knows that humans are mostly
water. For you, the key to fluid and electrolyte balance is
a knowledge of the various fluid compartments. An adult
male is 60% water; a female, having more fat, is 55%
water; newborn infants are 75% water. The most import-
ant compartments are the intracellular fluid (ICF) - 55%
of body water - and the extracellular fluid (ECF) - 45%.
Extracellular fluid is further subdivided into the plasma
(part of the intravascular space), the interstitial (Latin
inter - between + sistere = to stand; the fluid between the
cells) fluid, the transcellular water (e.g. fluid in the
The capillary membrane
1. The barrier between the plasma and interstitium
(Latin inter = between + sistere = to stand; hence intercellu-
lar spaces) is the capillary endothelium, which allows the
free passage of water and electrolytes (small particles) but
restricts the passage of larger molecules such as proteins
(the colloids - Greek kolla = glue + eidos ~ form). Although
no one has demonstrated holes in the membrane, capil-
laries behave as if they had pores of 4-5 nm (Greek
nanos = dwarf; 10~ 9 ) in most tissues. Kidney and liver
capillaries have larger pores but brain capillaries are
relatively impermeable.
1. The osmotic (Greek otheein = to push) pressure
generated by the presence of colloids on one side of a
membrane which is impermeable to them is known as the
colloid osmotic pressure (COP). Only a small quantity of
albumin (mol, wt 69 000) crosses the membrane and it is
mainly responsible for the difference in COP between
the plasma and the interstitium. In fact any particle, elec-
trolyte or protein, can exert an osmotic pressure, but the
free diffusion of electrolytes across the capillary wall
negates their osmotic effect. Passage of proteins across
the capillary wall is impeded in the normal state. For
this reason they exert an osmotic effect within the capil-
lary, commonly referred to as the colloid osmotic pres-
sure or oncotic (Greek onkos = mass; referring to the
107
9
PATIENT ASSESSMENT
7.5%=3.5I
DCT
i
7.5%=3.5I
plasma
20%=8.5I
interstitium
55%=23l
ICF
functional ECF
2.5%
=11
TCW
Fig. 9.1 Distribution of total body water in a 70 kg man. DCT, dense connective tissue; ECF, extracellular fluid; ICF,
intracellular fluid; TCW, transcellular water.
larger particle size) pressure. The osmotic effect of these
proteins is about 50% greater than would be expected
for the proteins alone. The reason for this is that most
proteins are negatively charged, attracting positively
charged ions such as sodium - the Gibbs-Donnan effect.
These positively charged ions are osmotically active and
therefore increase the effective osmotic pressure.
3. The COP is normally about 25 mmHg and tends to
draw fluid into the capillary, while the hydrostatic pres-
sure difference between capillary and interstitium tends
to push fluid out. This balance was first described by the
physiologist Henry Starling at University College,
London, in 1896.
4. Staverman (1952) introduced the concept that differ-
ent molecules are 'reflected' to a different extent by the
membrane. This term, the reflection coefficient, varies
between zero (all molecules passing through the mem-
brane) and +1 (all molecules reflected). In disease states
when the capillary membrane becomes leaky, such as
sepsis and the systemic inflammatory response syn-
drome (SIRS), the reflection coefficient falls. Flow across
the membrane is represented by the equation:
V = K f S[P c - P lF ) - <x Up - %)]
where V is the rate of movement of water, Kf is the capil-
lary filtration coefficient, S is the surface area; P c and P, F
are the capillary and interstitial hydrostatic pressures, irp
and ir ]F are the plasma and interstitial oncotic pressures,
and cr is the reflection coefficient.
The cell membrane
The barrier between the extracellular and intracellular
space is the cell membrane. This is freely permeable to
water but not to sodium ions, which are actively pumped
out of cells. Sodium is therefore mainly an extracellular
cation, while potassium is the main intracellular cation.
Water moves across the cell membrane in either direction
if there is any difference in osmolality between the two
sides. Osmolality expresses the osmotic pressure across a
selectively permeable membrane and depends on the
number of particles in the solution, not their size. Normal
osmolality of ECF is 280-295 mOsm kg -1 . Since each
cation is balanced by an anion, an estimate of plasma or
ECF osmolality can be obtained from the formula: 1
Osmolality (mOsm kg -1 )
= 2 (Na + + K + ) + glucose + urea (mmol I -1 )
Osmolality is expressed per kilogram of solvent (usually
water), whereas osmolality is expressed per litre of solution.
The presence of significant amounts of protein in the solution,
as in plasma, means that the osmolality and osmolarity will not
be the same.
108
FLUID, ELECTROLYTE AND ACID-BASE BALANCE
9
Note that the colloids contribute very little to total osmol-
ality as the number of particles is small, although, as we
saw above, they play an important role in fluid movement
across the capillaries.
Movement of water between compartments
1. Consider what happens when a patient takes in
water, either by drinking or in the form of a 5% glucose
infusion, the glucose in which is soon metabolized. It is
rapidly distributed throughout the ECF, with a resultant
fall in ECF osmolality. Since osmolality must be the same
inside and outside cells, water moves from ECF to ICF
until the osmolalities are the same. Thus 1 litre of water
or 5% glucose given to a patient distributes itself through-
out the body water. In spite of being infused into the
intravascular compartment (3.5 litres) it will be dis-
tributed throughout the body water space (42 litres) of
which only 3.5/42, approximately 7.5%, is intravascular.
For this reason approximately 13 litres of 5% glucose
need to be infused to increase the plasma volume by
1 litre. By a converse argument we can see that someone
marooned on a life raft with no water will lose water from
all compartments.
2. Normal saline (0.9%) contains Na + and CI - at con-
centrations of 150 mmol l" 1 . If this is infused into a patient
it stays in the ECF because the water tends to follow the
sodium ion and osmolality matches that inside the cells,
thus there is no net movement of water into the cells.
Therefore a volume of normal saline given intravascularly
tends to distribute throughout the extracellular space. The
extracellular fluid makes up approximately 45% of the
body water, with the plasma volume being approximately
7.5%, and therefore 1/6 remains intravascular and 6 litres
need to be given to increase the plasma volume by 1 litre.
Equally, a patient losing electrolytes and water together,
as in severe diarrhoea, loses the fluid from the ECF and
not the ICF.
Key point
• Only 1/6 of 0.9% saline fluid given
intravenously remains in the vascular
compartment, the remainder enters the
interstitium.
3. Finally, consider the infusion of colloid solutions
(e.g. albumin, starch solutions and gelatins). The capillary
membrane is impermeable to colloid and thus the
solution stays in the plasma compartment (there are, of
course, circumstances in which it can leak out). A burned
patient losing plasma loses it from the vascular compart-
ment and initially there is no shift of fluid from the inter-
stitial space. As blood pressure falls, hydrostatic pressure
in the capillary falls, and if colloid osmotic pressure is
maintained, the Starling forces draw water and elec-
trolytes into the vascular compartment from the intersti-
tium. Because there are only 3.5 litres of plasma, losses
from this compartment lead to hypoperfusion and
reduced oxygen transport to tissues and are potentially
life-threatening. The use of hypertonic saline as a resusci-
tation fluid has become topical lately with reports of
improved survival (Mattox et al 1991). The theoretical
advantage of these solutions is that a small volume of
administered fluid provides a significant plasma volume
expansion. The high osmolarity of these solutions draws
tissue fluid into the intravascular space and thus should
minimize tissue oedema for a given plasma volume incre-
ment, leading to better tissue perfusion. They are limited
at present to single dose administrations and clinical data
are still relatively sparse.
4. Since the plasma is part of the ECF, any loss of ECF
results in a corresponding decrease in circulating volume
and is potentially much more serious than loss of an
equivalent volume from the total body water. For
example, compare a man losing 1 litre a day of water
because he is marooned on a life raft with a man losing
1 litre a day of water and electrolytes due to a bowel
obstruction. The man on the life raft will lose 7 litres in a
week from his total of 42 litres body water, i.e. a 17% loss.
The plasma volume will fall by 17%, which is survivable.
The man with a bowel obstruction, on the other hand,
loses his 7 litres from the functional ECF of 12 litres, i.e. a
58% loss. Losing more than half of the plasma volume is
not compatible with life.
NORMAL WATER AND ELECTROLYTE
1. We take in water as food and drink and also make
about 350 ml per day as a result of the oxidization of
carbohydrates to water and carbon dioxide, known as the
metabolic water. This has to balance the output. Water is
lost through the skin and from the lungs; these insensible
losses amount to about 1 litre a day. Urine and faeces
account for the rest. A typical balance is shown in
Table 9.1.
2, The precise water requirements of a particular
patient depend on size, age and temperature. Surface
area (1.5 litres H 2 m -2 daily) is the most accurate guide,
but it is more practical to use weight, giving adults
30-40 ml kg" 1 . Children require relatively more water
than adults, as set out in Table 9.2, Add requirements for
the first 10 kg to the requirements for the next 10 kg and
109
PATIENT ASSESSMENT
Table 9.1
Average daily
water balance for
a
sedentary adult in temperate conditions
!
J
Input (mt)
Drink
Output (ml)
1500
Urine
1500
Food
750
Faeces
100
Metabolic
350
Lungs
Skin
400
600
Total
2600
Total
2600
Table 9.2 Daily water requirements by body
weight in children
Weight Water requirements
(kg)
0-10
10-20
>20
4 mi kg ] h" 1
40 ml h" 1 + 2 ml kg" 1 h T for each kg >10 kg
60 ml h _1 + 1 ml kg" 1 h _1 for each kg >20 kg
likewise add to subsequent weight. Therefore, for a
25 kg child the basal requirements per hour should be:
(10 x 4) + (10 x 2) + (5 x 1) = 65 ml h" 1
3. The average requirements of sodium and potassium
are 1 mmol kg" 1 day 1 of each. Humans are very efficient
at conserving sodium and can tolerate much lower
sodium intakes, but they are less good at conserving
potassium. There is an obligatory loss of potassium in
urine and faeces and patients who are not given potas-
sium becomes hypokalaemic. As potassium is mainly an
intracellular cation, there may be a considerable fall in
total body potassium before the plasma potassium falls.
PRESCRIBING FLUID REGIMENS
When prescribing fluids, remember:
• Basal requirements
• Pre-existing dehydration and electrolyte loss
• Continuing abnormal losses over and above
basal requirements.
Give special consideration to intraoperative fluid balance,
as all three of the above apply. Normally nourished
patients taking nothing orally for a few days during
surgery unusually require intravenous feeding, although
some reports have shown that early feeding improves
postoperative recovery. Only in special circumstances is
intravenous feeding required; this topic is outside the
scope of this chapter.
Basal requirements
We have seen above the daily requirements of water and
electrolytes. From the various crystalloid solutions that are
available (Table 9.3), we can design fluid regimens for basal
requirements. Normal (0.9%) saline, Hartmann's Ringer-
lactate solution, 5% dextrose, and dextrose 4%-saiine 0.18%
are the most commonly used. Note that their osmolalities
are similar to that of ECF, that is, they are isotonic with
plasma. The purpose of the glucose is to make the solution
isotonic, not to provide calories, although a small amount
of glucose does have a protein-sparing effect during the
catabolism that follows a major operation and trauma. Our
standard 70 kg patient can be provided with the 24 h basal
requirements of 30-40 ml kg" 1 of water and 1 mmol kg*" 1 of
sodium in any of the ways shown in Table 9.4.
Potassium
None of these regimens supply significant amounts of
potassium. Potassium chloride can be added to the bags
and is supplied as ampoules of 20 mmol in 10 ml or 1 g
(=13.5 mmol) in 5 ml. Bags of crystalloid are available
with potassium already added and this is safer than
adding ampoules.
Key points
• Be aware that potassium can be dangerous;
hyperkalemia and acute change in potassium
levels may cause cardiac arrhythmias and
asystole.
• Never inject it as a bolus.
Tragedies have been reported to the medical defence
societies in which potassium chloride ampoules are mis-
taken for sodium chloride and used as 'flush', with fatal
consequences. Hyperkalaemia may also occur if potass-
ium supplements are given to anuric patients. Usually
wait until you are certain of reasonable urine output
before adding potassium to the regimen postoperatively.
Safe rules for giving potassium are:
• Urine output at least 40 ml rr 1
• Not more than 40 mmol added to 1 litre
• No faster than 40 mmol h~ 1 .
110
FLUID, ELECTROLYTE AND ACID-BASE BALANCE
9
Table 9.3 Content of crystalloid solutions
Name
Known as
Na +
ci-
K +
HCOj Ca 2 *
Calculated
{mmol I -1 )
(mQsm I" 1 )
Sodium chloride 0.9%
Normal saline
150
150
300
Sodium chloride 0.9%,
Normal saline + KG
150
190
40
380 ,
potassium chloride 0.3%
Sodium chloride 0.9%,
Normal saline + KCI
150
170
20
340
potassium chloride 0.15%
Ringer's lactate
Hartmann's
131
11 1
5
29 (as lactate)
280
Glucose 5%
5% dextrose
280
Glucose 5%, potassium
5% dextrose + KCI
40
40
360
chloride 0.3%
Glucose 5%, potassium
5% dextrose + KCI
20
20
320
chloride 0.15%
Glucose 4% r sodium
Dextrose saline
30
30
286
chloride 0.18%
Glucose 4%, sodium
chloride 0.18%
Dextrose saline + KCI
30
70
40
366
potassium chloride 0.3%
Glucose 4%, sodium
Dextrose saline + KCI
30
50
20
326
chloride 0,18%, potassium
chloride 0.15%
Sodium chloride 0.45%
Half normal saline
75
75
150
Sodium chloride 1.8%
Twice normaj saline
300
300
600
Sodium bicarbonate 8.4%
—
1000
1000
2000
Sodium bicarbonate 1.4%
—
167
167
334
Continuing loss
Patients with continuing losses above the basal require-
ments need extra fluid. The commonest example in anaes-
thetic and surgical practice is the patient with bowel
obstruction. Fluid can be aspirated by a nasogastric tube
to assess both volume and electrolyte content. Give saline
with added potassium to replace it. Dextrose saline is not
an appropriate fluid for this purpose because it contains
only Na 30 mmol H, and 5% glucose is even worse,
Hyponatraemia results if these solutions are used to
replace bowel loss.
Table 9,4 Basal water and sodium regimens for a
70 kg patient
on intravenous fluids
Solution
Volume (ml)
Na* (mmol) K + (mmol)
5% glucose
2000
0,9% saline
500
75
5% glucose
2000
— —
Hartmann's
500
65.5 2.5
4% glucose
2500
75
0.18% saline
To keep track of the fluids, keep a fluid balance chart.
Record all fluid in (oral and intravenous) and all fluid out
(urine, drainage, vomit, etc.). Every 24 h total them, allow
for insensible losses and record the balance, positive or
negative. Any patient on intravenous fluids should have a
daily balance, daily electrolyte measurements and a new
regimen calculated every day. Never use the instruction
'and repeat' in fluid management; it has led to disasters in
the past.
Correction of pre-existing dehydration
Patients who arrive in a dehydrated state clearly need to
be resuscitated with fluid over and above their basal
requirements. Usually this will be done intravenously.
Key points
• Identify from which compartment or
compartments the fluid has been lost.
• Assess the extent of the dehydration.
Resuscitate the patient with fluid similar in composition
and volume to that which has been lost. From what you
know about the movement of fluid between compartments
111
PATIENT ASSESSMENT
(see above) and the patient's history, you can usually
decide from where the losses are coming. As we have seen,
bowel losses come from the ECF, while pure water losses
are from the total body water. Protein-containing fluid is
lost from the plasma, and there may sometimes be a com-
bination of all three types of loss.
Assessment of deficit
Key point
• Occult untreated intraoperative hypovolaemia
may lead to organ failure and death long after
the operative period.
1 . Assessment of deficit is, by its very nature, retrospec-
tive and reactive. It is still far better to predict loss, such
as that experienced by patients who have received bowel
preparation for surgery, and replace fluid prospectively.
In estimating the extent of the losses, take into account the
patient's history, clinical examination, measurement and
laboratory tests. A dehydrated patient may be thirsty,
have dry mucous membranes, sunken eyes (and in
infants fontanelles), cheeks, loss of skin elasticity and
weight loss. They feel weak and, in severe cases, are men-
tally confused, all of which are soft endpoints for ade-
quate resuscitation; do not rely upon them in isolation.
The cardiovascular system provides harder endpoints for
resuscitation with tachycardia and peripheral vasocon-
striction as the body responds with an endogenous sym-
pathetic drive, so that the patient feels cold. Prior to the
fall in blood pressure seen in continuing haemorrhage,
there is evidence that other organs, such as the gut, can
suffer from occult hypoperfusion. A study by Hamilton-
Da vies et al (1997) showed that, in progressive haemor-
rhage, gastrointestinal tonometry demonstrated gut
mucosal hypoperfusion greatly in advance of blood
pressure, heart rate or arterial blood gas changes.
The famous American surgeon, Alfred Blalock
(1899-1964), commented in 1943 after his experiences of
war, Tt is well known by those that are interested in this
subject that the blood volume and cardiac output are
usually diminished in traumatic shock before the arterial
blood pressure declines significantly/
2. Next follow decreases in stroke volume, which up
until this point have been maintained by a decrease in the
capacitance of the vascular system. Cardiac output falls,
causing a compensatory rise in heart rate and, eventually,
a fall in blood pressure. At this point the protective
autoregulation of blood flow to the brain, heart and
kidneys may fail and severe dehydration produces cloud-
ing of consciousness and oliguria. Carry out the simple,
essential measurements of weight, pulse, blood pressure
and urine output, to assess and treat fluid loss - although
sympathetic drive from the nervous system may mis-
leadingly maintain blood pressure until very late.
3. Measure central venous pressure (CVP). Insert an
intravenous catheter into a central vein. The catheter tip
should lie within the thorax, usually in the superior vena
cava. In this position, blood can be aspirated freely and
there is a swing in pressure with respiration. Measure the
pressure, usually with an electronic transducer, although it
can be done quite simply by connecting the patient to an
open-ended column of fluid and measuring the height
above zero with a ruler. The zero point for measuring CVP
is the fifth rib in the midaxillary line with the patient supine,
corresponding to the position of the left atrium. The normal
range for CVP is 3-8 cmH 2 (1 mmHg = 1.36 cmH 2 0). A
low reading, particularly a negative value, confirms dehy-
dration, but the converse is not true. A high or normal CVP
does not indicate an adequately filled vascular system. For
example, a patient on a noradrenaline (epinephrine) infu-
sion or with a high intrinsic sympathetic tone may have a
high CVP in spite of a low volume, high resistance vascu-
lar system. CVP measurements are of more use as a guide
to the adequacy of treatment.
Key point
• The response of the CVP to a fluid challenge of
200 ml colloid tells you more about the state of
the circulation than a single reading.
4. A dehydrated patient's CVP rises in response to
the challenge but then falls to the original value as the
circulation vasodilates to accommodate the fluid. If the
response to the challenge is a sustained rise (5 min after
the challenge) of 2-A cmH 2 0, this indicates a well-filled
patient. If the CVP rises by more than 4 cmH 2 and does
not fall again, this indicates overfilling or a failing
myocardium. A fluid challenge is the only logical way of
attempting acutely to restore the intravascular volume.
5. The CVP reflects the function of the right ventricle,
which usually parallels left ventricular function. In cardiac
disease, either primary or secondary to systemic illness,
there may be disparity between the function of the two
ventricles. The left ventricular function can be assessed by
inserting a balloon-tipped catheter (Swan-Ganz) into a
branch of the pulmonary artery. When the balloon is
blown up to occlude the vessel, the pressure measured dis-
tally gives a good guide to the left atrial pressure. This is
called the pulmonary capillary wedge pressure (PCWP)
and is normally 5-12 mmHg. In certain circumstances the
CVP may be high when the PCWP is low, which then indi-
cates that, although the right atrium may be well filled, the
112
FLUID, ELECTROLYTE AND ACID-BASE BALANCE
9
filling state of the systemic circulation is low. Here, as with
the fluid challenge of the CVP, manage the filling status of
the patient by means of fluid challenging the PCWP.
Similar changes in level apply.
6. Both intra opera tively and on the intensive care unit
there are many ways to monitor flow-based values such
as stroke volume and cardiac output. Measurement is
easy and with minimal morbidity using simple and effec-
tive systems such as the oesophageal Doppler monitor.
Slightly more invasive systems, such as pulse contour
analysis or pulmonary artery flotation catheters, also
provide useful flow-based information but do cause a
slightly higher morbidity. Whatever method you choose,
and it is most likely that variants will be used on the
general wards in the near future, they all allow you to
challenge a haemodynamic variable with fluid to bring
about an improvement in flow. Pressure is of secondary
importance; it is easy to generate pressure in an occluded
vessel but impossible to generate flow which brings with
it oxygen and all the means by which a cell survives.
Key points
• Elderly patients have poor cardiovascular
system compliance.
• Consider frequent small volume fluid
challenges.
• Left ventricular failure does not equate to
hypervolemia.
7. Work performed by Shoemaker et al (1988) demon-
strated that the Swan-Ganz catheter can be used to treat
patients to oxygen delivery /consumption goals when
undergoing high risk surgery They found that an
improved outcome followed in those who achieved goals
of:
m
• Oxygen delivery 2 > 600 ml min
• Oxygen consumption 3 > 1 70 ml min -1 m~ 2
• Cardiac index > 4.5 1 min -1 m~ 2
However, one argument is that these patients are self-
selecting and that they would have had a good outcome
anyway as they are able to achieve these goals / thus
demonstrating better cardiovascular function. Boyd et al
(1993) also demonstrated an improvement in outcome in
patients treated with the inotropic sympathomimetic
dopexamine to achieve these goals. Again, the same argu-
ments apply. There are now many studies based around
boosting oxygen delivery with a combination of fluids
and inotropes in an attempt to decrease surgical morbid-
ity and mortality These have recently been analysed in a
formal Cochrane meta-analysis by Grocott et al (2003),
which proves that high risk surgical patients undergoing
a process of optimization are not only significantly less
likely to die as a result of surgery but may also suffer less
morbidity as well. This is not true of an intensive care
population where it has been shown that, if critically ill
patients are subjected to a similar style of management by
driving their cardiovascular systems to achieve these
goals with fluid and inotropes, this group fare worse than
a control group (Hayes et al 1994). This may simply
reflect the fact that a significant insult has already
occurred which is not remediable to boosting oxygen
delivery.
8. In summary, a reasonable form of management is
to aim to achieve delivery /consumption goals in cardio-
vascularly fit subjects undergoing high risk surgery.
However, in patients with cardiovascular disease, seek
to achieve these goals only using fluid and agents that
offload the left ventricle, such as glyceryl trinitrate, thus
reducing myocardial work. Prefer to perform this under
Swan-Ganz monitoring of cardiac function, trans-
oesophageal echocardiography or the more recent non-
invasive oesophageal Doppler cardiac output monitor.
For those in whom these goals are unattainable, turn
your attention to ensuring an otherwise meticulous
perioperative course.
9. Occult hypovolaemia can be detected by measuring
gut mtramucosal pH (pHi). This has been demonstrated
as the area that first suffers during haemorrhagic blood
loss (Price et al 1966) and thus is possibly the first to
develop acidosis due to anaerobic metabolism. It can be
assessed by means of a saline-filled balloon passed into
the gut lumen which equilibrates with the carbon dioxide
generated in the gut mucosa. From this can be derived the
intramucosal pH. This value has been related to outcome
following high risk surgery (My then et al 1993) and
studies are currently being devised to investigate the
effects of resuscitating patients to a pHi endpoint. The
technology has recently been extended to an automated
air-filled balloon in combination with an end-tidal carbon
dioxide monitor (Tonocap), thus eliminating user bias
due to sampling technique differences. Current trials with
this device are in progress.
2 Oxygen delivery = cardiac output x Hb x arterial saturation x
1.34.
3 Oxygen consumption = cardiac output x Hb x (arterial - mixed
venous saturations) x 1.34.
Quantification of plasma and ECF loss
1. If plasma is lost from the circulation, that remaining
still has the same albumin concentration, although the
113
PATIENT ASSESSMENT
volume is diminished. Since no red cells are lost they
become concentrated, resulting in a rise in haematocrit.
Plasma is, of course, part of the ECF, so that losses of fluid
and electrolytes without protein loss will cause a rise in
haematocrit but also a rise in plasma protein concentration
(Fig, 9.2). Changes in plasma albumin and haematocrit thus
provide a good guide to ECF losses, while only haematocrit
is of use in monitoring plasma loss (Robarts et al 1979).
Key point
• In ECF depletion, the total amount of albumin
stays the same, although its concentration goes
up.
Haematocrit and plasma albumin are thus very useful in
the assessment of ECF and plasma losses; much more so
than the sodium which, though being lost, does not
change in concentration.
2. Table 9.5 summarizes the changes in volume and
composition of various compartments in:
• isotonic fluid loss
• loss of water in excess of electrolytes
• loss of sodium in excess of water.
The corresponding expansion of compartments is also
shown. It is a useful exercise to work through the various
boxes predicting what change, if any, will occur. In the
case of water loss (from both ECF and ICF) remember that
the red cells are part of the ICF, so when water is lost from
both compartments the haematocrit may not change.
Similarly, when there is hypotonic expansion, red cells
increase in volume as part of the ICF, and with the simul-
taneous expansion of ECF there may again be no change
in haematocrit.
Water and electrolyte replacement
Having assessed the amount of deficit, as discussed above,
now decide what to give to correct it. The composition of
plasma
rbcs
Interstilium
Interstilium
B
fnlerstitium
Fig. 9.2 A Loss of ECF leading to a rise in albumin concentration and haematocrit. B Loss of plasma leading to a rise
in haematocrit but no change in albumin concentration.
114
FLUID, ELECTROLYTE AND ACID-BASE BALANCE
9
Table 9.5 Changes resulting from three kinds of expansion
and contraction of body fluids
Acute change
Example
Change in
ECr vol
Change in
ICF vol
Change in
[Na]
— >
T
I
->
T
i
Change in
[Hctl
Change in
[protein]
Loss H 5 + NaCl
Loss H 2 > Na
Loss Na > H 2
Isotonic expansion
Hypertonic expansion
Hypotonic expansion
Cholera
Excess sweating
Addison's
Saline infusion
2 x normal saline
5% glucose infusion
i
I
i
T
T
T
— *
1
T
— ►
1
T
T
— >
T
1
i
T
T
T
i
i
i
various body fluids (Table 9.6) shows us that ECF losses of
water and electrolytes should be replaced either with
normal saline or Ringer's lactate with added potassium
(see Basal requirements, p. 110). The only hypotonic secre-
tions are saliva and sweat. The sodium content of sweat
varies and responds to aldosterone. Gastric secretion,
although having a sodium content of only 50 mmol l" 1 , is
isotonic with ECF because of the hydrogen it contains.
When the losses are primarily of gastric secretion, such as
pyloric stenosis, you might think it necessary to supply
hydrogen ions. In fact, the kidney compensates by retain-
ing hydrogen and excreting sodium and bicarbonate so
that the net effect is a loss of sodium and chloride.
Rehydrate, therefore, with normal saline with potassium.
Plasma replacement and plasma substitutes
1 . When you need to replace lost plasma there is a choice
between giving plasma prepared from donated blood or
one of the synthetic plasma substitutes. Human plasma
protein fraction (HPPF) or human albumin solution (HAS)
is prepared by separating red cells from donated blood. A
bottle contains plasma from several donors and has been
pasteurized to prevent the transmission of disease such as
hepatitis or human immunodeficiency virus (HIV). It con-
tains 4.5% albumin, has no clotting factors and is stable at
room temperature. The main disadvantage is its cost (£46 in
the UK, 1999), which reflects its limited availability. The
costs of blood and blood derived products are higher. Blood
is already leucodepleted to reduce the risk of infection and
transfusion reactions, which significantly adds to the cost
of production. A recent meta-analysis suggested that
administration of human albumin in the critically ill
patient may increase mortality (Schierhout & Roberts
1998). However, this analysis included studies looking at
albumin use for both hypoalbuminaemia, which is not
common current clinical practice in the perioperative
setting, and hypovolaemia. Albumin administration in
the management of hypovolaemia is also relatively
uncommon because of the high cost, and because the
semisynthetic colloids are considered to be at least as
effective. This analysis looked at a number of studies, half
of which show benefit for this indication, in widely diver-
gent populations and so does not provide a clear message
to influence clinical practice. Rather, it suggests the need
for a well-designed randomized controlled trial with
appropriate outcome goals. A number of solutions con-
taining molecules large enough to stay within the capil-
laries and generate colloid osmotic pressure are available
as plasma substitutes (Table 9.7).
2. Dextrans are glucose polymers available in prepara-
tions of different molecular weights. There is a large range
of molecular weights in the solution. Dextran 70 is so
called because the average molecular weight is supposed
to be 70 000. In fact, the number-average molecular
weight, which is much more relevant to the colloid
osmotic pressure, is 38 000 (see footnote to Table 10.7)
(Webb et al 1989). Dextran 40 has smaller molecules and
can be nephrotoxic. Dextran 110 has larger molecules.
Neither of these will be considered further. Dextran 70 is
Table 9.6 Electrolyte content and dally volume of body secretions
Na
Mmmol 1 ')
CI
Volume (litres dail
Saliva
15
19
40
1.5
Stomach
50
15
140
2,5
Bile, pancreas, small bowel
130-
145
5-12
70-100
4.2
Insensible sweat
12
10
12
0.6
Sensible sweat
50
10
50
Variable
115
<n
Table 9.7 Characteristics
of colloid solutions
Name
Brand name
No. average*
mol. wt
Mol. wt range Na* K* Ca 24
(mrnol I" 1 )
f,^ in plasma Adverse
reactions (%)
Effect on
coagulation
Cost
(UK
1988)
Mild
Severe
Human plasma protein
fraction
HPPF
69 000
69 000 1 50 5 2
20 days 0.02
0,004
None
£40
Dextran 70 in saline
0.9% or glucose 5%
Macrodex
Lomodex 70
Gentran 70
38 000
<10 000 > 250 000 150
12 h 0.7
0.02
Inhibit platelet
aggregation
Factor Villi
Interfere with
crossmatch
£4.78
Polygeline
(degraded gelatin)
Haemactel
24 500
<5 000-»50 000 145 5 6.25
2.5 h 0.12
0.04
None
£371
Succinylated gelatin
Gelofusin
22 600
<10 000~^ 140 000 154 0,4 0.4
4h 0,12
0.04
None
£4 r 63
Hydroxyethyl starch
6% in saline (hetastarch)
Hespan
70 000
<10 000->10 6 154
25 h 0.09
0.006
>1.5 g kg 1 day !
can cause
coagulopathy
£16.25
rers.
*Number-average molecu
ar weight should not be confused with weight-average molecular
weight, which is usua
lly quoted by the manufactu
Number-average molecular weight is more appropriate.
<^>
3
>
m
LA
to
2
FLUID, ELECTROLYTE AND ACID-BASE BALANCE
9
quite a good plasma substitute, but its use has declined in
popularity because of its adverse effects on coagulation
and crossmatching and the relatively high incidence of
allergic reactions.
3. Gelatin solutions are prepared by hydrolysis of
bovine collagen. They have the advantage over dextrans
of not affecting coagulation and of having a low incidence
of allergic reactions. Being of smaller average particle
size, they stay in the intravascular space for a shorter
time. Haemaccel contains potassium and calcium ions,
which can cause coagulation if mixed with citrated blood
in a giving set. Haemaccel stays for a shorter time in the
circulation: 30% of the molecules are dispersed to the
interstitial tissues within 30 min. Gelofusin is probably
preferable from this point of view.
4. Hetastarch, 6% in saline/ has become available in the
last few years. It has the largest average molecular weight
of any of the plasma substitutes and therefore stays in the
circulation longer. Limit the dose to 1500 ml 70 kg" 1 ; more
can cause coagulation problems. About 30% of a dose is
taken up by the reticuloendothelial system without
apparent detriment to its function. Smaller molecules
(mol. wt <50 000) are filtered by the kidneys. Larger ones
are broken down by plasma amylase until small enough
for real excretion.
5. Electrolyte balanced colloid solutions, such as Hextend,
represent a new area of fluid development and it is
possible that these solutions offer increased benefit over
currently used colloids, due to provision of a more
favourable physiological milieu. Indeed, clinical trials to
date with balanced colloids (Wilkes et al 2001) suggest
those undergoing major surgery benefit from better
acid-base profiles and end-organ perfusion than those
receiving traditional colloids suspended in 0.9% saline. It
is now well recognized that intravenous fluids based on
so called 'normal saline' do not represent the physiologi-
cal composition of plasma and in excess lead to a variety
of organ dysfunctions, such as those reported by Wilkes
et al, and others including cerebral, renal, gut and
metabolic dysfunction. Until recently it has been difficult
to explain why, but with new theories of acid-base physi-
ology emerging (see later), the pathophysiology of why
'normal saline' causes acidosis is easy to explain. In
essence 0.9% saline (normal saline) is not normal at all. It
has approximately 150 mmol of chloride and 150 mmol of
sodium per litre. When given in excess, which may be as
little as 2-3 litres per 24 h, it can produce high levels of
chloride, which in turn lead to the development of a mild
acidosis by reducing the strong ion difference (see later).
Choice of solution for plasma expansion
1. The intravascular space can be expanded by using
crystalloid solutions such as saline, but because the fluid
spreads throughout the ECF, 6 litres of crystalloid are
needed to expand the plasma by 1 litre. In an emergency,
crystalloid is useful. All the battle casualties in the
Falklands War were resuscitated in the field with
Hartmann's solution.
2. Do not use 5% glucose from choice as it is dis-
tributed throughout both ECF and ICF compartments;
thus 13 litres are needed to increase the intravascular
space by 1 litre. For most patients with acute hypo-
volemia, the best combination of advantages at low cost
is offered by succinylated gelatin (Gelofusin). Being rela-
tively short acting, it is particularly useful as a holding
measure until blood becomes available. Gelofusin proba-
bly stays within the intravascular space for 60-90 min at
most.
3. In continuing hypovolemia, hetastarch gives more
prolonged expansion and its larger molecules are better
retained in the circulation when the capillaries are leaky,
e.g. in septicaemic shock.
4. There is continued debate as to whether it is better
to resuscitate with a crystalloid or colloid, the so-called
crystalloid versus colloid debate. There have been many
meta-analyses that failed to prove any advantage of one
over the other for the purpose of resuscitation. Indeed, the
most common conclusion is that there are insufficient
data available to recommend one rather than the other. A
trial of sufficient power to demonstrate a mortality dif-
ference using either crystalloid or colloid would need to
include over 7000 patients. Trials of that size are currently
under way in Australia but are likely to add to the debate
rather than resolve it.
Blood loss and blood transfusion
1. So far we have considered plasma loss and plasma
expansion. Most of what has been said about the assess-
ment and replacement ot plasma volume applies to blood
loss. Transfusion of donated blood is possible in most cir-
cumstances, but has several disadvantages to be weighed
against the fact that only haemoglobin carries oxygen.
With a haemoglobin of 14 g dL\ evolution has equipped
us with spare capacity as far as oxygen-carrying capacity
is concerned. Indeed, as haematocrit falls, the decrease in
oxygen carrying is compensated by better tissue perfu-
sion due to reduced blood viscosity.
2. It has been shown that the best balance between
oxygen carrying and viscosity occurs around a haemato-
crit of 30%. It is also suspected that blood transfusion at
the time of surgery for certain cancers leads to immuno-
logical suppression and poorer long-term survival. On
the other hand, blood transfusion prior to transplant pro-
cedures improves graft survival. Because of anxiety over
HIV, and with a lack of knowledge of mechanisms of
prion transfer relating to bovine spongiform encephalitis
117
PATIENT ASSESSMENT
(BSE), there is reluctance by the public to accept blood
transfusion. Trials in critical care suggest that restricting
transfusion to patients with Hb below 8 g% is associated
with a better outcome (Hebert et al 1999).
3. For these reasons, in addition to the hazards of blood
transfusion listed in Table 9.8, the expense of blood and
rarity of some blood groups, there is reluctance to trans-
fuse blood. In practical terms, operative blood loss up to
500 ml can be replaced with saline, remembering that
six times as much will be needed (see above), or plasma
substitutes. Only if more than 1 litre of blood has been lost
in a healthy adult should you consider giving blood.
Point of care testing with Hb analysers or from arterial
blood gases will allow you to quantify the need for trans-
fusion; use them when possible. Anaemia alone is a diffi-
cult clinical sign on which to base the prescription of
blood.
4. Rather than supply whole blood, it is more efficient
for the transfusion service to separate it into components
(Table 9.9). Blood cross-matched for patients undergoing
surgery usually comes as plasma-reduced blood -
'packed cells'. This is more viscous than whole blood so
give it with appropriate amounts of crystalloid or colloid
solution to restore the volume.
5. Assess the quantity of blood lost by clinical means,
as outlined above. At operation, watch the suction bottle
and weigh swabs, although this generally underestimates
the loss. The only real way of quantifying loss is by
arterial blood gases measurement, full blood counts
performed in the laboratory, or by bedside testing by, for
example, Haemacue when available. In operations such
as transurethral resection of the prostate, measurement of
haemoglobin in the irrigating fluid gives an accurate
measure of blood loss. Haematocrit and haemoglobin
concentrations do not change in acute blood loss until the
blood remaining in the patient has been diluted by shift
Table 9.9 Blood products
Table 9.8 The hazards of blood transfusion
Any transfusion
• Transmission of disease, e.g. AIDS, malaria (donor
blood screened for HIV, hepatitis, syphilis)
• Bacterial contamination
■ Pyrogenic reactions (antibodies to white cells)
• Incompatibility reactions
• ± Haemolysis (clerical error commonest cause)
Massive transfusion
• Hypothermia
■ Hyperkalaemia
■ Citrate toxicity
• Acidosis
• Microaggregate embolism, 'shock lung"
• Dilution and consumption of clotting factors
Plasrna-reduced blood {packed cells)
Washed red cells: if transfusion reaction a
problem
Plasma protein fraction (HPPF)
Fresh frozen plasma {FFP): contains clotting
factors more dilute than the concentrates below
Cryopredpttate: rich in factor VIM
Factor VIII concentrate: even richer in VIM
Factors M, VII, IX and X concentrate
Factor XI concentrate
Fibrinogen
Platelet concentrate
of fluid from the interstitial space or intravenous infu-
sion. Plasma-reduced blood and whole blood more than
1 day old, which it almost always is, contain no viable
platelets and a few clotting factors. The same applies to
plasma protein fraction. In massive transfusion both dilu-
tion and consumption of clotting factors make it necess-
ary to send blood for a clotting screen and give platelets
and fresh frozen plasma (FFP) according to the results. As
a rule, give a unit of FFP for every 4-6 units of stored
blood transfused. Contact haematologists for advice (see
Ch. 8).
6. As stored blood is generally collected into citrate-
containing bags, remember that exogenous calcium may
be required after massive blood transfusion, to ensure
both adequate haemostasis and a normal vascular
response to inotropes.
Intraoperative fluid balance
1. During an operation, many of the problems dis-
cussed so far may be continuing. The patient is starved for
6-12 h, there may be blood loss, plasma loss, ECF loss and
evaporation of water from exposed bowel. As part of the
stress response to surgery the patient retains water and
sodium. The importance of careful monitoring in major
surgery is obvious, including accurate assessment of
blood loss, haemodynamic variables and urine output.
2. As a rule of thumb, in intra-abdominal surgery, give
up to 2 litres of Hartmann's solution 5 ml kg" 1 rr 1 . This
compensates for starvation, ECF loss, evaporation and
some blood loss. You may need to give blood or colloids
in addition. If the patient is being treated in an attempt to
achieve oxygen delivery /consumption goals, in cardio-
vascularly healthy patients, continually challenge the
central venous pressure (CVP) with fluid. In those with
cardiac dysfunction, challenge the pulmonary capillary
wedge pressure (PCWP) to maintain an optimal haemo-
dynamic state.
118
FLUID, ELECTROLYTE AND ACID-BASE BALANCE
9
3. For the first 36 h postoperatively there is water
retention, and there is sodium retention lasting 3-5 days.
Obligatory potassium loss of 50-100 mmol per day con-
tinues. If you give additional sodium it is simply retained,
although the urine may show an increase in sodium
output. Provided that intraoperative losses have been
replaced by the end of the operation, give the basal
requirements: 30-40 ml kg -1 day 1 H 2 + 1 mmol kg" 1 day -1
Na + and K + , plus additional blood or colloid if there is
significant wound drainage.
4. Do not give potassium until urine output is estab-
lished; the operation of inadvertent bilateral ureteric
ligation is not unknown.
ACID-BASE BALANCE
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Claude Bernard was the first to recognize that to function
effectively the body needs a stable milieu interieur. The
hydrogen ion concentration is the most important contri-
bution to this. An acid is a hydrogen ion (proton) donor
and a base accepts hydrogen ions. Throughout life the
body produces hydrogen ions and they must be excreted
or buffered to keep the internal environment constant. It
is testament to the importance of hydrogen ions that they
are regulated on a nanomolar level rather than millimolar
as are most of the principle anions and cations in the
blood. There are currently two main ways of interpreting
acid-base balance. The first or 'traditional view' is the
most widespread interpretation and based on work
by Severinghaus, Henderson-Hasselbalch and Siggard-
Anderson among others. It evolved as technology became
more advanced and allowed for the direct measurement of
carbon dioxide and hydrogen ion activity and the calcula-
tion of those values which were unmeasurable. The 'new'
interpretation of acid-base balance takes much of this pio-
neering work and develops it further on the basis of sound
physicochemical principles. For the most part the new
theory, proposed by Stewart in the early 1980s, states that
there are only three variables that influence pH: carbon
dioxide, the strong ion difference (SID) and weak acids.
Both methods are described below for completeness.
Traditional view of acid-base balance
Terminology and definitions
Hydrogen ion activity. This is traditionally
expressed in pH units, pH being the negative log 10 of the
hydrogen ion concentration:
pH = -log [H + ] = log
1
[H + ]
pH is a log scale, so that each 0.3 unit fall in pH represents
a doubling of hydrogen ion concentration.
Acidosis and alkalosis. The normal ECF pH is
7.36-7.44 (44-36 nmol r 1 ). Acidaemia is a blood pH below
this range and alkalaemia a pH above it. Acidosis is a
condition that leads to acidaemia, or would do if no
compensation occurred, but the terms 'acidosis' and 'aci-
daemia' are often used loosely to mean the same thing,
which is not strictly correct. Alkalosis and alkalaemia are
denned in a similar way.
• Respiratory acidosis is a fall in pH resulting from a rise
in the Pco^ e.g. opiate overdose leading to hypo-
ventilation causes a rise in Fco 2 .
• Respiratory alkalosis is a rise in pH due to a lowering of
the Pc0 2 , such as occurs in hyperventilation.
• Metabolic acidosis is a fall in pH due to anything other
than carbon dioxide (sometimes referred to as non-
respiratory acidosis). There is a primary gain of acid or
loss of bicarbonate from ECF.
• Metabolic alkalosis is a rise in pH from non-respiratory
causes. There is either a gain in bicarbonate or a loss of
acid from the ECF.
• Compensatory changes. If the initial problem is respir-
atory, the result is called a primary respiratory acidosis or
alkalosis. If the respiratory problem persists for more
than a few hours, the kidney excretes or retains bicar-
bonate to try and compensate for the respiratory dis-
turbance. This is referred to as secondary or compensatory
metabolic acidosis or alkalosis.
Thus a primary respiratory acidosis may be accom-
panied by a secondary metabolic alkalosis. For example,
chronic obstructive airways disease leads to a rise in the
Pco 2 : primary respiratory acidosis. To compensate for
this the kidney retains bicarbonate, leading to a rise in
ECF bicarbonate: secondary or compensatory metabolic
alkalosis.
In the same way, primary respiratory alkalosis (e.g.
the hyperventilation that occurs at high altitude) will
be compensated by a secondary metabolic acidosis.
Hydrogen ion concentration can also be expressed
directly in nanomoles per litre (Table 9.10). Note that the
Table 9.10
Conversion
table for pH units and
hydrogen i
on concentration
pH unit
H* (nmol I »)
8.00
10
7,70
20
7,44
36
7.40
40
7.36
44
7,10
30
7.00
100
119
PATIENT ASSESSMENT
Where the first disturbance is metabolic, e.g. the
buildup of acid in diabetic ketoacidosis, the primary
metabolic acidosis will cause hyperventilation (sec-
ondary respiratory alkalosis), which will tend to restore
the pH to normal. This respiratory compensation for a
metabolic change happens much more rapidly than the
metabolic compensation for a respiratory problem.
The fourth possible combination of changes is to
have a metabolic alkalosis such as loss of H + in pyloric
stenosis, compensated by a respiratory acidosis.
However, hypoventilation (respiratory acidosis) leads
to a fall in Po 2 , which stimulates ventilation so that, in
practice, compensatory respiratory acidosis is not
usually seen.
In deciding which is the primary and which is the
secondary change, realize that the compensatory
changes do not bring the pH back to normal; they
bring it back towards the normal range. In other words,
even after compensation the measured pH is altered in
the direction of the primary problem (acidosis or
alkalosis). Compensatory mechanisms merely make
the disturbance in pH less than it otherwise would
have been. It is also important to consider the history.
Examiners may give candidates blood gas results to
interpret, but in real life blood gases come from
patients. Knowing that a patient is an unconscious
diabetic breathing spontaneously, rather than an
anaesthetized patient on a ventilator, certainly helps
one's interpretation.
Buffers. These are substances which, by their pres-
ence in solution, minimize the change in pH for a given
addition of acid or alkali. Three-quarters of the buffering
power of the body is within the cells; the rest is in the
ECF. Proteins, haemoglobin, phosphates and the bicar-
bonate system are all important buffers. The particular
importance of the bicarbonate system is that carbon
dioxide is excreted in the lungs and can be regulated by
changes in ventilation. Bicarbonate excretion in the
kidney can also be regulated. The lungs are responsible
for the excretion of 16 000 mmol per day of acid and the
kidneys for only 40-80 mmol per day. The formation of
carbonic acid from carbon dioxide and water is catalysed
by carbonic anhydrase (present in red cells). The reaction
may go in either direction:
H + + HCOi <-> H 2 C0 3 <-> H 2 + C0 2
The Henderson-Hasselbalch equation is derived from
this and expresses the relationship between the bicarbon-
ate concentration, the carbon dioxide and the pH:
[HC0 3 ]
pH = pK + log
[HCQ 3 ]
0.03 Pco 2
pH = pK + log
[H 2 C0 3 ]
The carbonic acid can be expressed in terms of carbon
dioxide, so that a more useful form of the equation is:
As this is a buffer system which minimizes changes in pH,
we can see that if the carbon dioxide rises so will the
bicarbonate, to keep [HCO^\/Pco 2 constant. Similarly, a
fall in bicarbonate will be accompanied by a fall in Pco 2
to prevent a change in pH.
Interpretation of acid-base changes
As the patient's acid-base status varies, three things are
changing at once: pH, IHCO3] and Pco 2 . Blood gas
machines measure Po 2/ pH and Pco 2 directly. The actual
bicarbonate [HCO3] is calculated from the Henderson-
Hasselbalch equation. Blood gas machines also derive
other variables which help in the interpretation of the
acid-base status; however, these all attempt to describe
the metabolic derangement. These are as follows:
1. Standard bicarbonate (SBC) is the concentration of
bicarbonate in the plasma of fully oxygenated blood at
37 D C at a Pco 2 of 5.3 kPa (40 mmHg). In other words, it tells
you what the bicarbonate would be if there were no respir-
atory disturbance. Looking at the standard bicarbonate
therefore tells you what is going on on the metabolic side.
Normal standard bicarbonate is 22-26 mmol T 1 . Values
above this indicate metabolic alkalosis, and those below,
metabolic acidosis.
2. Base excess (BE) is the amount of strong base or acid
that would need to be added to whole blood to titrate the
pH back to 7.4 at a Pco 2 of 5.3 kPa and 37°C. It tells you
the same thing as standard bicarbonate, namely the
metabolic status of the patient. Normal base excess is
obviously zero (±2 mmol \" 1 ). Positive base excess occurs
in metabolic alkalosis, and negative base excess (some-
times called base deficit) indicates metabolic acidosis. The
base excess is an in vitro determination in whole blood. It
is also known as the actual base excess (ABE) or the base
excess (blood) (BE b).
3. Standard base excess (SBE) is an estimate of the in vivo
base excess and takes into account the difference in buffer-
ing capacity between the patient's ECF and the blood that
was put in the blood gas machine. Interstitial fluid, having
less protein and no haemoglobin, has a lower buffering
capacity than blood. SBE is therefore 1-2 mmol 1 _1 greater
than BE, but this makes very little difference in practice.
SBE is sometimes called base excess (e.c.f.).
4. Total carbon dioxide (Tco 2 ) is the total concentration of
carbon dioxide in the plasma as bicarbonate and dis-
solved carbon dioxide.
Tco 2 = [HCOi] + (Pco 2 x solubility)
5. Oxygen saturation (0 2 sat.). The percentage saturation
of haemoglobin by oxygen is derived from the haemoglobin
120
FLUID, ELECTROLYTE AND ACID-BASE BALANCE
9
oxygen dissociation curve and the measured Po 2 . The
normal value is >95%. Do not rely on this value to be
accurate, as other forms of haemoglobin, such as carboxy-
haemoglobin, are included as oxyhaemoglobin. If you
suspect this, for example in burns patients, then use a co-
oximeter to determine the level of oxyhaemoglobin.
6. Po 2 and inspired oxygen (Fio 2 ). To interpret the Po 2 you
need to know the age of the patient and the Fio 2 . Normal
arterial Po 2 declines with age. Roughly speaking Po 2 = 100
- age in years/3 mmHg or 13.3 - 0.044 x age kPa.
The expected alveolar Po 2 (Fao 2 ) can be predicted from
the inspired oxygen by the simplified alveolar gas equa-
tion: Pao 2 = Pio 2 - Paco 2 /R, where R is the respiratory
exchange ratio (normally 0.8). In dry gas Pio 2 (in kPa) =
fractional inspired oxygen (Fio 2 )%. Alveolar gas is satu-
rated with water vapour (6.3 kPa), for which allowance
must be made. If the Fio 2 = 40% and the Pco 2 = 5.3:
Pao, =
(40 - 40 x 603) 5.3
100
0.8
= 30.85 kPa
As an approximate rule of thumb, deduct 10 from the
Fio 2 % to give the expected Pao 2 in kPa (e.g. if Fio 2 = 50%
then Pao 2 should be approximately 40 kPa). The difference
between the estimated Pao 2 and the measured arterial Po 2
is called the (a - a) Po 2 gradient. It is normally 0.5-3 kPa.
Without considering the inspired oxygen it is not poss-
ible to comment sensibly on the observed Pao 2 . A rough
calculation of the (A - a) Po 2 gradient should be made
when commenting on blood gas results. Some machines
even calculate this for you as well!
A blood gas machine usually prints out the variables
shown in Table 9.11 There is often a haemoglobin
measurement and the temperature of measurement
(37°C) is quoted, and in some cases an electrolyte profile
may be included.
7. Temperature correction. The blood gas machine oper-
ates at 37°C. Because gases are more soluble in liquid at
lower temperatures (as drinkers of cold lager will know),
the blood gases would be different if measured at another
Table 9.11 Printout from a blood gas machine
with normal values
Temp.
pH
Pcq 2
Po 2
HC0 3
Tco ?
SBC
BE
SBE
O^sat.
Hb
37°C
7.36-7.44 (44-36 nmol M)
4.6-5.6 kPa (35^12 mmHg)
10.0-13.3 kPa (75-100 mmHg)
22-26 mmol I 1
24^28 mmol I ]
22-26 mmol I ]
-2 to +2 mmol h 1
-3 to +3 mmol M
>95%
1 1.5-16.5 g dM
temperature. Blood gas machines are programmed to
correct the gases if you tell the machine the patient's
actual temperature. However, there has been much debate
as to whether it is appropriate to correct for temperature.
Suffice it to say that the protagonists of not correcting for
temperature (the alpha stat theory) hold sway and one
should probably act on the blood gases as measured at
37°C and not the temperature-corrected values.
8. The anion gap. For electrochemical neutrality of the
ECF the number of anions must equal the number of
cations. The main cations are sodium and potassium and
the main anions are chloride, bicarbonate, proteins, phos-
phates, sulphates and organic acids.
Normally, only Na + , K + , HCOi and CI" are measured in
the laboratory. Thus, when we add the normal values for
these they do not balance:
Cations
Na + 140
K + 5
Total 145
Anions
CI" 105
HCOi 25
Total 130
The difference is known as the anion gap and represents the
other anions not usually measured. Anion gap = (Na + + K + )
- (HCO3 + CI ) = 11-19 mmol H. Its significance is that in
certain metabolic acidoses (e.g. ketoacidosis or lactic
acidosis) the anion gap will be increased by the presence
of organic anions. However, in metabolic acidosis in which
chloride replaces bicarbonate (e.g. bicarbonate loss due to
diarrhoea), the anion gap will be normal. It is simply
another way in which to further elucidate the cause of the
acidosis.
New insights into acid-base physiology
Conventional methods of interpreting acid-base balance
are centred on the Henderson-Hasselbach equation,
which describes a ratio of carbon dioxide to bicarbonate
to derive the pH. The respiratory component of the equa-
tion is easy to comprehend because carbon dioxide is part
of the equation, but the metabolic component is less easy
to understand. We use surrogate markers of metabolic
disturbance, such as base excess, to quantify the degree of
metabolic acidosis. There has been an increasing aware-
ness that this model, which works clinically, fails to
explain much of the associated pathophysiology, in
particular the influence of electrolytes and proteins on
acid-base balance. In 1981 Paul Stewart (1981) took a
physicochemical approach to acid-base balance and came
up with a model, which has subsequently been modified
by Fencl, that explained many of these anomalies. He said
that for all aqueous systems there must be electrical
neutrality and conservation of mass, and that water will
dissociate/ associate to give /receive hydrogen ions if the
121
PATIENT ASSESSMENT
balance of either is altered. He also identified the import-
ant factors controlling acid-base balance control.
Only three independent factors
control acid-base balance:
• Pco 2
• Strong ion difference (SID)
• Weak acids (albumin and phosphate).
All other variables such as hydrogen ions, hydroxide,
bicarbonate, etc. change only if one or more of the three
independent variables changes.
1. Pco 2 . The change in carbon dioxide is self ex-
planatory and influences the pH as predicted by the
Henderson-Hasselbach equation.
2. SID. Strong ion difference refers to the mathematical
difference in charge between the strong ions in solution
and is normally between 38 and 42 mmol L 1 . Strong ions
are those ions which in solution are virtually fully dissoci-
ated, e.g Na + , CI", K + , Ca 2+ , Mg 2+ and, for the purposes of
the model, lactate. For example, if NaCl is added to water
there is virtually complete dissociation and the only things
that exist in that solution are Na + , CI", H 2 0, H + and OH"
ions; there are no y NaCl molecules'. If there is a change in
the concentration of one of these ions, that is an increase in
the CI", then the SID will be reduced and electrical neu-
trality has to be restored. This results in the dissociation of
water, so producing hydrogen ions and decreasing the pH
of a solution. Therefore, increasing the chloride concentra-
tion makes the system more acidic. The increase in the
hydrogen ion concentration, however, is only in the
nanomolar range and does not restore electrical neutrality.
The bulk of electrical neutrality is restored by the proteins.
3. Weak acids. Albumin and phosphate are the pre-
dominant weak acids. If the concentration of albumin
decreases, the solution becomes more alkaline. This is a
very common occurrence in the critical care patient.
It is therefore possible, if you know the Pco 2 , the SID
and the weak acid concentration, to work out what the
pH will be without having to measure it. It is this degree
of quantification that allows physicians working in com-
plicated critical care or postoperative environments to
understand the pathophysiology behind the disturbance
and work out what and how to treat it effectively.
PLAN FOR INTERPRETING BLOOD
GASES
1. Check for internal consistency. Remember that the
machine measures only pH, Pco 2 and Po 2 . If it measures
any of these wrongly, which is not infrequent, the derived
variables are also wildly abnormal. If the results do not fit
with the clinical picture, suspect the machine. Example: a
patient on a ventilator in theatre with an end- tidal carbon
dioxide of 5% has the following gases:
Po 2
13.0
pH
7.64
Pco 2
5.1
hco 3 -
37.5
Tco 2
38.5
SBC
39.0
BE
+15
SBE
+16
2 sat.
99%
It is much more likely that the pH has been measured
wrongly than that the patient has a gross metabolic
alkalosis.
2. Look at the pH. Remember the pH change is always
in the direction of the primary problem acidosis or
alkalosis.
3. Look at the Pco 2 . Abnormality of the Pco 2 indicates
the respiratory component.
4. Look at the base excess or standard bicarbonate.
Both give the same information, i.e. the metabolic
acid-base status after correcting for the Pco 2 .
5. Calculate the anion gap.
6. Look at the Po 2 and calculate the A - a gradient.
Examples of abnormal blood gases
The alkalaemia is due to primary
respiratory alkalosis (low Pco 2 ).
There is no metabolic
compensation (normal base
excess). The Po 2 would be
expected if breathing 40%
oxygen Pio 2 - 10 = (40 - 10) = 30.
The patient is
hyperventilating.
A respiratory acidosis with high
PC0 2 due to hypoventilation.
Again no metabolic compensation
(normal SBC and BE). Low Po 2
due to hypoventilation.
pH
7.51
Pco 2
3.7
Po 2
29
HC03
22.1
Tco 2
23.6
SBC
25
BE
+1.1
SBE
+2
2 sat.
100%
(Fio 2 40%)
pH
7.28
Pco 2
7.33
Po 2
9.21
HC03
25.2
Tco 2
28.4
SBC
22.3
BE
-1.9
SBE
-2.5
2 sat.
91%
(Fio 2 air)
pH
7.35
Pco 2
9.33
Again a respiratory acidosis
(high Pco 2 ) but this time
122
FLUID, ELECTROLYTE AND ACID-BASE BALANCE
9
Po 2
7.11
hco 3
39.1
Tco 2
41.2
SBC
32.4
BE
+8.2
SBE
+9.1
2 sat.
85%
(Fio 2 air)
pH
7.21
Pco 2
4.0
Po 2
13.3
HCOi
11,5
Tco 2
12.8
SBC
9.3
BE
-15.2
SBE
-16.4
2 sat.
99%
(Fio 2 air)
pH
7.36
Pco 2
4.21
Po 2
10.49
HCOi
17.6
Tco 2
18.5
SBC
17.8
BE
-6.2
SBE
-6.9
2 sat.
96%
(Fio 2 60%)
compensated by metabolic
alkalosis (high SBC and positive
base excess). This is typical of
chronic obstructive airways
disease with renal
compensation.
The acidaemia (low pH) is
primarily due to a metabolic
acidosis (low SBC, base excess
-15). Compensatory
respiratory alkalosis (low Pco 2 ),
does not return the pH to
normal. Po 2 normal.
The pH is in the normal range
despite low Pco 2 (respiratory
alkalosis) and low standard
bicarbonate (metabolic
acidosis). The important thing
here is the Po 2 . It is apparently
in the normal range but not
when breathing 60% oxygen.
The (A - a) Po 2 gradient is
roughly 40 kPa. These gases are
typical of a patient with adult
respiratory distress syndrome.
a cardiac arrest is probably unjustified. In metabolic
acidosis due to poor perfusion of tissues the best way to
manage this is to correct the perfusion defect, which may
be achieved, in some instances, by improving oxygen
delivery using fluids, vasodilators or inotropes. This may
involve the use of invasive monitoring such as Swan-
Ganz catheterization in order to guide therapy. Treatment
of the metabolic acidosis due to sepsis is controversial
and, even though goal-directed therapy may not be uni-
versally accepted, most will still try to achieve reasonably
high oxygen delivery targets. In sepsis, however, this does
not give the anticipated rise in oxygen consumption,
after allowing for the rise in oxygen consumption due
to increased myocardial work required to achieve the
delivery. Sepsis appears to involve a defect in tissue
oxygen uptake /utilization.
4. There is still a place for bicarbonate therapy in
acidosis due to diarrhoea, renal tubular acidosis and
uraemic acidosis, and where an imbalance of the SID exists.
As outlined above, use the base excess to calculate the
dose; 8.4% sodium bicarbonate is hyperosmolar and must
be given into a large central vein. Accidental subcutaneous
administration can cause tissue necrosis. Bear in mind
that each millimole of HCO3 is accompanied by Na + and
it is easy to overload the patient with sodium.
Key point
Frequently monitor blood gases and
electrolytes during treatment with
bicarbonate.
TREATMENT OF ACID-BASE
DISTURB^
1. As in any other field of medicine, direct treatment at
the underlying cause. Correcting the Pco 2 is usually poss-
ible by taking over the patient's ventilation and adjusting
the minute volume to give the desired Pco 2 .
2. Treatment of a metabolic acidosis is more contro-
versial. It was traditional to treat a metabolic acidosis by
giving sodium bicarbonate according to the formula (base
excess x body weight in kg/ 3) mmol starting by giving half
the dose; 8.4% sodium bicarbonate contains 1 mmol ml" 1 .
3. It is now argued that, particularly in a hypoxic state
such as exists following cardiac arrest, bicarbonate
administration may do more harm than good (Graf &
Arieff 1986). The bicarbonate generates carbon dioxide,
which crosses easily into cells, making the intracellular
acidosis worse. If ventilation is impaired the carbon
dioxide generated is unable to escape via the lungs. The
traditional practice of giving 50-100 mmol bicarbonate at
Summary
• Do you have an adequate knowledge of
basic fluid physiology?
• Do you recognize that visible fluid deficit
is but a small part of the overall problem?
• Are you aware that occult intraoperative
hypovolaemia leads to increased
postoperative morbidity?
• Will you determine to monitor patients
thoroughly to fully understand their fluid
status?
• Are you aware that hypovolaemia is the
most common cause of intraoperative
metabolic acidosis?
• Do you recognize that hypovolaemia is
probably the most common avoidable
cause of multiple organ dysfunction?
123
PATIENT ASSESSMENT
References
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trial of the effect of deliberate peri-operative increase of
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Edelman IS, Leibman J 1959 Anatomy of body water and
electrolytes. American Journal of Medicine 27: 256, 277
Graf H, Arieff AI 1986 Use of sodium bicarbonate in the therapy
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Grocott MPW, Hamilton MA, Rowan K 2003 Perioperative
increase in global blood flow to explicit defined goals and
outcomes following surger; issue 1, January, Cochrane
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Hamilton-Davies C, Mythen MG, Salmon JB, Jacobson D,
Shukla A, Webb AR 1997 Comparison of commonly used
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Hayes MA, Timmins AC, Yau EH 1994 Elevation of systemic
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Mattox KL, Maningas PA, Moore EE 1991 Prehospital
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Robarts WM, Parkin JV, Hobsley M 1979 A simple clinical
approach to quantifying losses from the extracellular and
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Starling EH 1896 On the absorption of fluids from the
connective spaces. Journal of Physiology 19: 312-326
Staverman A 1952 Apparent osmotic pressure of solutions of
heterodisperse polymers. Rec Trav Chim 71: 623-633
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acid-base primer for biology and medicine. Edward Arnold,
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Analgesia 93(4): 811-816
124
Nutritional support
J. Payne-James
W
Objectives
Be aware of the incidence, causes, effects
and assessment of protein energy
malnutrition in surgical patients.
Recognize when and how to administer
oral, enteral and parenteral support, and
when to stop it.
Be aware of the complications of
administering support.
Document your findings and actions.
INTROpUCTipN
The metabolic response to injury, such as major trauma
or surgical operation and sepsis, generates increased
demand for nitrogen and energy. If the demands are not
met, the patient develops protein-energy malnutrition
(PEM), which is a significant and often unrecognized
problem in hospitals, with up to 40% of patients under-
nourished, and fewer than half of these having this fact
documented in their notes.
Aim to identify actual or potential malnourished patients
and correct or improve their nutritional status to minimize
the risks of chest, urinary or wound infection, slow healing,
wound breakdown or even death. The optimal method of
administering additional nutrients is by oral feeding, such
as sip feeds and dietary supplements, both in hospital and
community practice. A variety of flavours is available in
order to make the supplements palatable. When oral
feeding is not possible because the patient is incapable, or
lacks motivation, seek other routes of administering nutri-
ent substrates to critically ill or postoperative patients.
ASSESSMENT
Key points
Assess all patients admitted to hospital, even
for elective procedures.
• Record the results.
• Decide whether or not nutritional support will
be required.
Specific aspects help in classifying nutritional status:
• Record height and weight for comparison with stan-
dard charts.
• Estimate from the dietary history and from the assump-
tion that maximum requirements of protein and energy
for hospitalized patients are 1.5 g kg" 1 24 h -1 , and
40 kcal kg" 1 24 h" 1 respectively.
• Assess body composition clinically.
• It may be difficult to identify PEM. Look for and record
signs such as loss of muscle power, peripheral oedema,
skin rashes, angular stomatitis, gingivitis, nail abnor-
malities, glossitis, paraesthesia and neuropathy.
• Tests may have poor sensitivity. Compare midarm
muscle circumference with tables and measure triceps
skinfold thickness, for which you need special
calipers. Apply dynamometric tests such as hand-grip
strength. Assess serum albumin (normal 36^7 g l" 1 ),
transferrin (normal 2-4 g l" 1 ) assess the lymphocyte
count (normal 1.5-4 x 10 9 l" 1 ) and delayed hypersensi-
tivity skin testing.
In the absence of a specific measure, clinically place each
patient in one of the following groups:
1. Obvious severe malnutrition, recent or long term
(>10% recent weight loss, serum albumin <30 g 1 _I ,
gross muscle wasting and peripheral oedema).
2. Moderate malnutrition, with low nutritional
parameters, impaired nutrient intake for more than
2-4 weeks, although there may be no obvious
physical evidence.
3. Normal or near-normal status but at risk of
deteriorating without support in traumatized or
ventilated patients.
4. Normal nutritional status which is unlikely to be
affected by illness.
If 1, 2, 3 nutritional support maybe needed. If so, deter-
mine the best route of administration (Fig. 10.1).
125
10
PATIENT ASSESSMENT
Normally
nourished
Normal feeding
Oral feeding!
sip feeds/diet
supplements
Nutritional assessment
I
Normal/near-normal
nutrition state (but
will deteriorate if
support withheld)
Severe/moderate
malnutrition
1
Nutrition support indicated
Yes
Oral nutrition possible
I
Yes
EN
Gastrointestinal tract
functions adequately
No
\
PN
Limited EN
possible
I
Supplement
with PN
EN
anticipated for < 2 weeks
Fine-bore
nasoenteral tube
I
EN
anticipated for > 2 weeks
I
Consider placement of
long-term tube
Feeding prolonged
> 2 weeks
PN anticipated
for < 2 weeks
I
Peripheral PN
(PPN)
I
PN anticipated
for > 2 weeks
I
Central venous
PN <CPN)
"7
Feeding prolonged > 2 weeks y
or poor peripheral access
Fig. 10.1 Flow chart of options when nutritional support is required. CPN, central venous parenteral nutrition; EN,
enteral nutrition; PN, parenteral nutrition; PPN, peripheral parenteral nutrition.
ENTERAL AND PARENTERAL
NUTRITION FOR SURGICAL PATIENTS
> ;£4^'^%*l / ^!& : $$f«>i!gM : A
Key point
• Prefer enteral feeding for all patients with a fully
functioning, accessible gastrointestinal tract.
1. Enteral feeding may improve antibacterial host
defences, blunt the hypermetabolic response to trauma,
maintain gut mucosal mass, maintain gut barrier function
and prevent disruption of gut flora. It may contribute to
maintaining splanchnic blood flow and the direct provi-
sion of nutrients for enterocytes. The gut was previously
considered unimportant during critical illness caused by
injury or infection. It is now recognized that the gastro-
intestinal tract is frequently a reservoir for bacterial
translocation across the gut wall. Gut-derived endotoxin
may therefore be a link between gastrointestinal failure
and multiple organ failure without overt clinical evidence
of infection (Fig. 10.2).
2. Research is being carried out to determine whether
dietary manipulation, such as provision of glutamine or
fibre, can prevent bowel atrophy and maintain intestinal
mass, in the hope of reducing morbidity and mortality.
3. For the majority of critically ill patients, including
postoperative patients, the gastrointestinal tract is the
appropriate route for nutritional support, provided it is
functioning normally. Because small intestinal function is
better maintained postoperatively than gastric and large
bowel function, enteral (small bowel) feeding can start
126
NUTRITIONAL SUPPORT
10
SYSTEMIC INSULT
(eg shock, injury, infection
immunosuppression
malnutrition)
Gl INSULT
(eg. inflammatory bowel
disease, radiotherapy,
chemotherapy)
I
i
THERAPEUTIC AGENTS
(antibiotics, H? blockers)
Impaired host defences
Physical disruption of gut mucosal barrier
Overgrowth of pathogenic gut flora
i
TRANSLOCATION OF BACTERIA
I
SYSTEMIC RESPONSE
MULTIPLE ORGAN DYSFUNCTION SYNDROME
(MODS)
Fig. 10.2 Simplified mechanism of bacterial
translocation and multiple organ failure.
dietary supplementation, enteral or parenteral
nutrition.
• Do not delay operation if the disease is
progressing, causing the patient's condition to
deteriorate.
• Do not delay operation solely on account of
borderline or mild malnutrition.
Postoperative nutrition
1. Consider postoperative nutrition for any patient
with an inadequate intake after 5 days.
2. Give parenteral nutrition if oral or enteral nutrition
is not anticipated within 7 days post-operation in a pre-
viously well-nourished patient and as early as possible in
a previously malnourished or critically ill patient.
3. Consider creating access to the gastrointestinal tract
via a gastrostomy, a jejunostomy or a central venous
feeding line at the time of major oropharyngeal, maxillo-
facial or upper gastrointestinal operation. This spares the
patient a second procedure and the access lines can be
disconnected if they are not needed.
4. In extreme circumstances, such as an elderly, mal-
nourished smoker requiring ©esophagectomy, provide
preoperative nutritional support and arrange to continue
it afterwards. By contrast, a patient with perforation of a
viscus from inflammatory bowel disease unresponsive to
medical management needs operation first, nutritional
support afterwards.
early following operation, including major aortic and
small bowel surgery, and following head injuries.
4. The benefits of enteral nutrition in patients who
would formerly have been given parenteral nutrition have
been demonstrated, although patients in whom there is
reasonable doubt as to the adequacy of gastrointestinal
function should be fed by the parenteral route. There are
no differences in major postoperative complications and
mortality rates; however, in certain groups (e.g. malnour-
ished gastrointestinal cancer patients) who receive early
enteral nutrition, significantly reduced complication rates
and shorter duration of postoperative stay may be achieved
with enteral nutrition, although parenteral nutrition is
better tolerated. In summary total parenteral nutrition is
an equally effective alternative to enteral nutrition when
a risk of malnutrition is present and enteral nutrition is
not tolerated or when gut failure is present.
Preoperative nutritional support
Give a severely malnourished (e.g. more than
10% weight loss) patient at least 10 days of
ENERGY AND NITROGEN
RETIREMENTS
Many surgical patients in need of nutritional support are
metabolically stressed, septic or traumatized by accident or
operation. In particular, those with burns or head injuries
are likely to be hypermetabolic as a result of neuroen-
docrine responses. Although precise energy requirements
can be determined by indirect calorimetry, this is not a prac-
tical approach. Energy requirements to achieve positive
energy balance in surgical patients are rarely more than
2200-2400 kcal 24 h" 1 . Give 35-40 kcal kg" 1 24 h" 1 as a
mixture of carbohydrate and fat, which is usually sufficient.
Nitrogen requirements may be considerable; in hyper-
metabolic, stressed and injured patients it may be imposs-
ible to achieve a balance until the underlying cause has
been improved. Minimize losses in order not to waste
administered nitrogen, maintain lean body mass, allow
an adequate supply for repair and allow active repletion
of lean body mass in a previously compromised patient.
For most adults 14-16 g nitrogen suffices. For those who
require even more nitrogen, up to 0.4 g kg -1 24 h _1 has
been suggested.
127
10
PATIENT ASSESSMENT
When patients are on nutritional
support, frequently monitor and
chart:
• Diet
• Weight
• Haematology
• Biochemistry.
Keep accurate records of actual as opposed to prescribed
intake, in order to identify any nutritional inadequacies
promptly. They are particularly important during the
changeover to oral feeding. Regularly weigh to ensure
that the regimen is satisfactory, especially in those requir-
ing body mass repletion. Weight gain may represent
water retention, however, but this is revealed if you regu-
larly monitor haematological and biochemical results.
Especially in the first few days and in the malnourished
patient, monitor the plasma potassium, phosphate and
glucose. Measure vitamin and trace elements in patients
on long-term feeding if appropriate. The response to
nutritional support may be judged over days and weeks
by the levels of plasma proteins, transferrin and thyroid
prealbumin.
Although anthropometric and dynamometric measure-
ments are often considered as research tools, they offer
sensitive, effective measurements of nutrition, so use
them when they are available.
Nitrogen balance
An aim of nutritional support is to try and ensure that the
patient is in positive nitrogen balance. This is often diffi-
cult or impossible to achieve in patients who are very
physiologically stressed or catabolic, the phase of destruc-
tive metabolism, in the immediate aftermath of trauma or
injury and in the critically ill.
Nitrogen balance depends upon the difference between
whole body protein synthesis and breakdown. It is more
a measure of the metabolic than the nutritional state. In
most patients nitrogen balance can be calculated from
urinary and faecal nitrogen losses. Collect 24 h samples of
urine, as faecal loss is often negligible. Urinary urea may
reasonably be considered to account for 80% of total
urinary nitrogen. Adjust for plasma urea levels and for
faecal and other routes of loss of 2-3 g.
In a severely ill patient, urinary urea may not represent
80% of urinary nitrogen, because of excessive excretion of
ammonia and other non-urea nitrogenous products. If
chemiluminescence measurement of total urinary nitro-
gen is available, there is no need to estimate output from
urea values.
ENTERAL JSIU
Types of diet
Polymeric (Greek polys = much, many + meros = part) diets
contain whole protein as a nitrogen source, triglycerides
and glucose polymers for energy, together with stan-
dardized amounts of electrolytes, trace elements and vita-
mins. Standard polymeric diets contain approximately
6 g nitrogen 1 _1 with an energy density of 1 kcal ml" 1 .
Energy (nitrogen dense) diets contain 8-10 g nitrogen /l
and an energy density of 1—1.5 kcal ml" 1 . These diets are
suitable for more than 90% of patients with normal or
near normal gastrointestinal function. In those with
impaired intraluminal hydrolysis from severe pancreatic
exocrine insufficiency or intestinal failure from short
bowel syndrome, give a predigested or elemental diet.
Predigested or elemental diets have nitrogen sources
derived from amino acids or oligopeptides. Their benefit
over standard diets in acute pancreatitis has been
established. Glucose polymer mixtures with polymers
predominantly of chain length more than 10 glucose
molecules provide energy. A combination of long- and
medium-chain triglycerides provides the fat component.
Some disease-specific diets have been developed. High
carbohydrate loads increase carbon dioxide production in
patients with respiratory failure who are on ventilators;
diets containing a higher fat energy component may
allow the patient to be weaned from the ventilator as a
result of decreased carbon dioxide production and
reduced respiratory quotient.
Research is underway to design diets that modify or
modulate stress and the immune response. No general
recommendations are yet available but specific groups
such as the critically ill may benefit.
Route of administration
Most patients require nutritional support for less than
1 month. For these, a fine-bore nasogastric tube suffices.
Ensure that the tube is correctly positioned, especially if the
patient has altered swallowing, diminished gag reflex, or
has had surgery of the pharynx or upper airway. Confirm
that the tube is correctly placed by aspirating gastric con-
tents. If the patient is unable to cooperate, confirm the posi-
tion of the tube tip radiologically. It should preferably be
sited beyond the pylorus if gastric atony and regurgitation
are likely. Advance the tube using a combination of mani-
pulation and administration of a motility stimulant such as
metoclopramide. Longer term feeding may be provided by
percutaneous endoscopically placed gastrostomy or needle
catheter jejunostomy These techniques are valuable for
undernourished patients at presentation, those undergoing
128
NUTRITIONAL SUPPORT
10
major upper gastrointestinal operation, adjuvant radio-
therapy or chemotherapy, and those undergoing laparo-
tomy following major abdominal trauma. Anticipate the
problem at operation by placing the tube at the time; some-
times pharyngostomy or oesophagostomy may be used.
Anticipate and prepare for gastric
atony or paresis in:
• Critically ill and recumbent patients and
following head injury
• Patients being ventilated or needing intensive
care
• Following abdominal surgery
• Diabetes with neuropathy
• Hypothyroidism
• Neuromotor deglutition disorder
Preferably administer enteral diet from a large reservoir
holding up to 2 litres, from a sterile closed system, espe-
cially if the patient is immunosuppressed or critically ill.
Change the reservoir and giving set every 24 h. Prefer
continuous to intermittent bolus feeding, so avoiding
bloating and diarrhoea. Use gravity feed or a peristaltic
pump. A starter regimen of undiluted full-volume diet
does not, as is commonly thought, provoke gastrointesti-
nal side-effects in patients with normal bowel, or those
with inflammatory bowel disease. Starting with reduced
volume or diluting the feed limits the intake, thereby pro-
longing the duration of negative nitrogen balance. In
most adult patients with no other metabolic or fluid
balance problems, prescribe 2-2.5 litres of diet each day
from the beginning.
Complications
1 . Feeding tube blockage most usually occurs when the
giving set is disconnected and the residual diet solidifies.
Prevent it by flushing out the tube with water after dis-
connecting it. Unblock it by instilling pancreatic enzyme
or cola. The tube may be malpositioned or be inadver-
tently removed.
2. Diarrhoea, occurring in about 10% of patients, is
multifactorial, often associated with concomitant anti-
biotic treatment or hypoalbuminaemia. Only rarely do
you need to discontinue feeding, as codeine phosphate or
loperamide is usually effective. Review the drug chart fre-
quently and stop antibiotics if they are no longer required.
3. Nausea and vomiting are rarely caused by the feeds
but may develop because of slow gastric emptying; try
giving antiemetics. Too rapid administration, or bolus
feeding, may produce bloating, abdominal pain or
cramps. Regurgitation and pulmonary aspiration occa-
sionally occur.
4. Anticipate and prevent vitamin, mineral and trace
element deficiencies.
5. Enteral diets react with enterally administered drugs
such as theophylline, warfarin, methyldopa and digoxin,
especially if the patient is fed orally If drug therapy that
was effective fails during enteral feeding, assume it
results from the enteral feeding unless proved otherwise.
Key point
Exclude complications of infection originating
in the diet reservoir or giving set.
PARENTEjFTALJ
The successful use of intravenous parenteral (Greek para -
besides + enteron = gut, intestine) nutrition was first
demonstrated three decades ago. Parenteral nutrition (PN)
(often termed TPN - total parenteral nutrition - although
this is only true if all macronutrients and micronutrients
such as electrolytes, vitamins and trace elements are
included) is required for any patient with intestinal failure
(short term or long term). It is essential for some acutely ill
patients, although the increasing preference for the enteral
route is reducing this. About 25% of hospitalized patients
requiring nutritional support need it to be administered
parenterally. Consider it for actual or potential malnour-
ished patients with a non-functioning, partially function-
ing and /or inaccessible gastrointestinal tract. When in
doubt about gastrointestinal function, use parenteral nutri-
tion until you are reassured about gastrointestinal function-
Access
Parenteral nutrition solutions generally have high osmol-
alities (Greek otheein = to push; the tendency of water to
pass through a semipermeable membrane from the side
of lower concentration to the side of higher concentration,
to equalize the concentrations). Hypertonic solutions
infused into peripheral veins damage the endothelium,
causing thrombosis. This is overcome by introducing
them through a catheter passed into a large central vein,
such as the vena cava, where the concentrated fluid mixes
rapidly with the large volume of blood and is diluted.
The risk of introducing sepsis demands the highest
level of technical care. The catheter is usually passed
through a subcutaneous tunnel before entering the vein,
to distance the vein entry from the surface. If a patient
129
PATIENT ASSESSMENT
with a central venous catheter develops pyrexia and
raised leucocyte count, and has no detectable cause after
a rigorous search, assume it is catheter related.
The development of lower energy regimens in which
lipid provides a substantial part of the required calories
allows the administration of parenteral nutrition via
peripheral veins. Peripheral parenteral nutrition (PPN)
without provoking thrombophlebitis is facilitated by
using fine-bore cannulas, the use of heparin, in-line fil-
tration, Cortisol, buffering and the local application of
glyceryl trinitrate patches. In addition, most courses last
no more than 10-14 days.
Nutrients
Macronutrients, larger molecules, contain glucose and
lipid emulsions, usually 50:50 with nitrogen sources in the
form of L-amino acids. New lipids with better stability in
solution are now available; they can modulate immune
functions, inflammatory processes and metabolism, and
promise to become more widely used.
Micronutrients include electrolytes, trace elements and
vitamins, Commercial all-in-one bags contain mixed macro-
and micronutrients which can safely be infused over
12-24 h. They can be safely stored for several weeks. They
suit almost 80% of patients and are widely used. Ready-to-
use standardized formulations, either made up in pharma-
cies or presented as commercial multichamber bags,
simplify administration, and the most appropriate formula
best approximating the patient's needs can be chosen.
Key points
• Monitor blood glucose 6-hourly for the first
week to detect insulin resistance; you may
need to give exogenous insulin by injection or
infusion.
• Monitor electrolytes daily so you can detect
and correct imbalances.
• Monitor liver function to check serum albumin
and hepatobiliary dysfunction, which
inevitably results from parenteral nutrition in
some patients.
Complications
in
Metabolic complications of parenteral nutrition,
descending order of frequency are: hyperglycaemia,
hypoglycaemia, hypophosphataemia, hypercalcaemia,
hyperkalemia, hypokalaemia, hypernatraemia, hypo-
natraemia. In the longer term, anticipate deficiencies of
folate, zinc, magnesium, other trace elements, vitamins
and essential fatty acids.
Home parenteral nutrition
Some patients require long-term nutritional support by
virtue of loss of bowel by disease or resection. Such par-
enteral or enteral support demands commitment by you
as part of the surgical team, by skilled carers and by the
patients. Although patients can often be monitored
locally, overall management must be undertaken at a
special centre. The principles are the same as for inpatient
management but long-term monitoring and specific com-
plications are more complex. Those in need of home
nutritional support ahould be referred at an early stage.
NUTRITION SUPPORT TEAM
#£?^?^-W>&'
In hospital, the best way of optimizing nutritional care is
with a multidisciplinary support team, each member
providing specialty expert care. They receive input from
clinicians, dieticians, pharmacists, nurses, chemical
pathologists and microbiologists. A central support team
can establish specialized teams to attend to specific needs
in, for example, intensive care and paediatrics.
Summary
How does malnutrition affect surgical
outcome?
How do you assess the nutritional state of
your patients?
How do you identify and treat
malnourished patients?
What methods are available and how do
you select them?
What is the make-up of a nutritional
support team?
Further reading
Payne-James JJ, Wicks CW 2002 Key facts in clinical nutrition,
2nd edn. Greenwich Medical Media, London
Payne-James JJ, Grimble GK, Silk DBA (eds) 2001 Artificial
nutrition support in clinical practice, 2nd edn. Greenwich
Medical Media, London
130
Clinical pharmacology
J. Robin
Objectives
• Understand how drugs are developed and
licensed.
• Know how to select drugs rationally,
according to efficacy, safety, convenience
and cost.
• Learn to prescribe safely and effectively.
• Be aware of the use of drugs in special
situations.
• Beware of drug interactions whenever you
prescribe.
Almost all doctors prescribe drugs. As a budding
surgeon, you are no exception. You use drugs extensively
perioperatively. You also use drugs as first line therapy
for some conditions referred to you. Many of your
patients have an extensive list of medications prescribed
for coexisting diseases, some of them unfamiliar to you.
You often continue to prescribe these drugs while the
patient remains under your care.
This chapter aims to teach you the principles of select-
ing drugs rationally, and using them safely and effec-
tively. The British National Formulary (BNF) is a source of
much useful information for prescribers. Keep it to hand
as you study this chapter so you can refer to it. You need
to understand the various factors that influence your
decision to prescribe a particular drug to your patient,
and the consequences that flow from that decision. A drug
(the word is of uncertain origin) is any substance used in
the composition of a medicine.
DRUG DEVELOPMENT AND LICENSING
As a prescribes you need to have a basic understanding
of the process of drug development and marketing.
1. New drugs are continually developed and marketed
by the major pharmaceutical companies. Development
begins with the pharmaceutical company identifying an
'unmet medical need', such as diseases for which no effec-
tive therapy is available, or conditions for which the exist-
ing therapy is considered suboptimal in terms of efficacy,
tolerability or both.
2. Once the need is identified, the drug company syn-
thesizes novel compounds that might have some useful
pharmacological activity, called 'new chemical entities'
(NCEs). Any NCEs showing promise are immediately
protected by a patent, giving the company 20 years exclus-
ive rights to develop and market the drug. The attrition
rate for NCEs is high, the majority being discarded
because they do not work or are too toxic. Drug develop-
ment is expensive and time consuming: it can take up to
10 years to bring one to the market.
3. Once a drug is successfully developed the manufac-
turers apply for a product licence, the marketing permit,
with specific indications, specific patient groups and for
specific doses. Indications may be a symptom, disease or
a physiological derangement.
4. If a specialist chooses to prescribe a drug outside the
terms of its product licence (an unlicensed indication), the
prescriber, not the drug company, is responsible for any
harmful consequences.
Key point
Do not prescribe a drug outside its product
licence. Consult your senior colleagues.
The BNF contains thousands of established drugs for a
multitude of indications. Each year many existing drugs
gain new indications and hundreds of new drugs or new
formulations of existing drugs are added to the BNF.
For some indications the choice of drugs may be
bewildering and the marketing claims made for them
131
PATIENT ASSESSMENT
*M*MtaUM*iiirifeMHft?
may be very impressive at first glance. Sensibly evaluate
the real worth of drugs.
Key point
• Select drugs for their proven efficacy
(effectiveness), safety convenience and cost
not on the basis of claims made for them.
Efficacy
1. In order to gain a product licence, the pharmaceuti-
cal company must provide evidence from clinical trials
that a drug is at least more effective than placebo (Latin 'I
shall please'; treatment that pleases the patient rather
than exerts a curative effect). It need not demonstrate that
the drug is better than existing therapy.
2. The benefits of a drug over existing therapy may be
relatively small. To demonstrate a small clinical advan-
tage over existing therapy a large, lengthy and very
expensive clinical trial is often required.
3. The size, length and cost of a clinical trial can be
reduced by employing surrogate (Latin sub = in place of
+ rogare = to ask; substitute) as opposed to real endpoints.
A surrogate endpoint is some measurement or test that
plausibly suggests, but does not prove, genuine benefit to
patients, such as reduction in prostate size in benign pro-
static hypertrophy. Real endpoints (something the patient
will notice and is likely to bring benefit, such as a reduc-
tion in prostatic symptoms) provide a much more secure
basis for determining the clinical efficacy of a drug. Read
claims critically (see Chs 12, 45, 46).
■M*
Key points
• Ensure the trial patient group represents the
likely clinical patients, not younger or healthier.
• Has the new drug been tested against and
shown to be more effective than existing
therapy using real endpoints?
4. Efficacy data are often presented in the most favour-
able light. Reductions in relative risk are more impressive
than reductions in absolute risk, but reduction in absolute
risk is most important. To get a feel for the benefit of a
drug, consider the number needed to treat (NNT):
• Consider two drugs compared using relative risk. Drug
A reduces the relative risk of disease X by 50%. Drug B
reduces the relative risk of disease Y by 10%. Which is
the more effective drug? Drug A perhaps?
• It is impossible to say without knowing the absolute
risks of diseases X and Y. If the absolute risk of disease
X is 1%, drug A will reduce absolute risk by 0.5%. The
number of patients that need to be treated for one to
benefit (NNT) will be 100/0.5 - 200. However, if the
absolute risk of disease X is 50%, drug A will reduce
absolute risk by 5%. The number of patients that need
to be treated for one to benefit (NNT) will be 100/5 = 20.
• Now which is the most effective drug?
Assessing safety
1. So you have decided that a new drug offers a
genuine and clinically significant advantage over, or in
addition to, existing therapy. You must now investigate
the drug's safety profile. When you assess comparative
safety over placebo or existing therapy, again make sure
that the selected patient group is representative of the
patients that you actually treat. Relatively young and
otherwise healthy individuals are less likely to experience
significant side-effects compared with the elderly patients
with comorbidity that you might treat. Just as the concept
of absolute and relative risk may paint different pictures
in terms of benefit, they may also do so in terms of harm.
• Consider a new drug that is stated to increase only the
absolute risk of an adverse effect by 5% only. How safe
is the drug?
• It is impossible to say without knowing the absolute
risk of the adverse effect in patients not taking the drug.
If this risk is 20%, the drug will increase the relative risk
by 25%, but if it is 1%, the drug will increase the rela-
tive risk by 500%!
2, Also, make sure that, when compared to existing
therapy, equivalent doses in terms of efficacy were used.
Have low doses of existing therapy been used when
making comparisons of efficacy and high doses when
comparing safety and tolerability?
Surely the adverse effects are already known?
1. Most new drugs are purposely designed to enhance
target selectivity. This is often an important part of the
marketing message. Indeed, such an approach can poten-
tially minimize adverse effects and enhance tolerability.
2. New drugs, no matter how well designed, also have
a distinct disadvantage. Prior to gaining a licence, it is
unusual for a drug to have been tested in more than a
couple of thousand patients. It is often many fewer. While
dose-dependent, or predictable, adverse effects may have
been designed out during development, idiosyncratic
(Greek idios - one's own + syn = together + krasis = a
mixing; individual mental or physical constitution)
adverse effects may not yet have occurred with sufficient
frequency to be noticed. Idiosyncratic adverse effects are
often serious and sometimes fatal.
132
CLINICAL PHARMACOLOGY
11
3. Postmarketing surveillance is used to detect these
adverse effects as quickly as possible. In the United
Kingdom, the basis of postmarketing surveillance is the
Yellow Card Scheme. It is quite common for a new
'wonder drug 7 to be withdrawn a few months later as
an unacceptable side-effect profile becomes apparent
through the postmarketing surveillance.
Key points
• New drugs are not necessarily safer than
existing therapy.
• Moderately rare adverse effects are only
detected after the drug is marketed through
the process of postmarketing surveillance.
The Yellow Card Scheme
1 . This is a scheme that encourages doctors and phar-
macists to report all suspected adverse effects of new
drugs (marked with an ^ in the BNF) and serious and
life-threatening adverse effects of existing drugs.
2. Because the scheme is not compulsory, it is under-
used and only 10% of adverse effects are reported.
Key points
• Be alert to the possibility of unexpected adverse
effects, especially when prescribing drugs
marked ▼ in the British National Formulary .
• Report all suspected adverse effects of new
drugs.
• Report all serious and life-threatening adverse
effects of established drugs.
Convenience and cost
1. Sometimes a drug company freely admits that its
new drug is no safer or effective than existing therapy but
claims that it is more convenient. For instance, a drug may
need to be taken only once rather than twice daily. It is
suggested that it will improve patient compliance. In fact,
there is little evidence that once-daily preparations
achieve significantly better compliance than twice-daily
preparations, although both are better than three or more
times-daily drugs.
2. As a result of technological advances, a plethora of
expensive long-acting or slow-release formulations are
now marketed. As well as reducing dosing frequency, it
is often also claimed that they achieve smoother plasma
drug concentrations, which improves either efficacy,
tolerability, or both. Is there genuine clinical evidence to
support these claims?
3. The cost of a new drug should not be a primary con-
sideration in your decision whether or not to prescribe it
to an individual patient, but remember that a newer, and
inevitably more expensive, drug is not necessarily better.
You should be persuaded to prescribe an expensive new
drug only if you are convinced that it offers a genuine and
worthwhile advantage over existing therapy.
4. A number of very similar drugs may be developed
simultaneously for the same indication by different com-
panies. In such cases, it is sensible for you to select the
cheapest.
Key points
• Once- or twice-daily dosing improves
compliance compared with more frequent
regimens.
• Long-acting or slow-release formulations are
more expensive and may not necessarily confer
any clinical advantage.
• Prescribe a more expensive new drug only if it
offers worthwhile benefit over cheaper
existing therapy.
• When a range of very similar drugs exist, select
the cheapest in the class.
Gaining reliable information about drugs
1 . Many sources are available. They are not all helpful,
some may be misleading. Review articles or journal edi-
torials are usually balanced, but sometimes the authors
have links with the manufacturers. Carefully read the
small print at the end of the article stating the author's
potential conflicts of interest.
2. Recommendations from expert bodies are usually
but not always reliable,
3. Colleagues may be a useful source of information or
guidance.
4. Consult independent assessments, which are avail-
able nationally through the Drug and Therapeutics Bulletin
(DTB) and National Prescribing Centre (NPC). Locally,
hospital committees select new drugs from those avail-
able to list in the hospital formulary Except in very excep-
tional circumstances, use drugs on that list.
5. Consult guidance produced by the National Institute
for Clinical Excellence (NICE) on relevant drugs. Such guid-
ance recommends what drug technology should be made
available, but rarely how particular drugs should be inte-
grated with other treatment you wish to offer. You remain
responsible for deciding where and when to use the drug.
133
PATIENT ASSESSMENT
Key point
Obtain and critically evaluate the best and
most reliable information available about
drugs.
USING DRUGS
may even have a lower starting dose for elderly patients,
so check the BNR
'■^^'fi^'s^-^^
Favour prescribing from a personal selection of formulary
drugs with which you are familiar. From time to time, as
new evidence becomes available, you might rationally
add or substitute new drugs according to the principles
outlined above. You will also know that your patients
vary in their individual clinical response to drugs.
Therefore, in order to use drugs both safely and effec-
tively, you should carefully tailor your prescribing to the
characteristics of the individual patient. Individual vari-
ability is manifested in both pharmacodynamic ('what the
drug does to body' including both desired and adverse
effects) and pharmacokinetic ('what the body does to the
drug') responses, according to such factors as age,
disease, genetic background and other drugs the patient
is taking.
Elderly
1. Patients of advanced age consume most of the drugs
that are prescribed. Although no drugs are specifically
contraindicated in the elderly, exercise particular caution
when prescribing drugs to this group. In particular, be
aware that the elderly are often more sensitive to both the
effects and adverse effects of a drug. There are many
reasons for this. Drug elimination becomes progressively
impaired with age, causing drug accumulation. In addi-
tion, the adverse effects of many drugs are blunted by
physiological compensatory responses. These compen-
satory responses are less efficient in the elderly.
2. Elderly patients are more likely to have coexisting
disease that may alter their response to drugs. Other dis-
eases mean that other doctors are involved and frequently
this results in them taking a long list of drugs, often with
little rational justification - 'polypharmacy' - (Greek polys
- much, many). This significantly increases the potential
for drug interactions.
3. Before prescribing, ask yourself whether your
elderly patient really requires an additional drug? If so,
perhaps this is a good time to ask a medical colleague
specializing in the care of the elderly to rationalize the
patient's therapy. If you do decide to prescribe, start with
the lowest possible dose and titrate the dose gradually
upwards until the desired effect is achieved. Some drugs
Key points
• The elderly are more sensitive to the effects
and adverse effects of drugs.
• Polypharmacy in the elderly increases the
potential for drug interactions.
• Avoid prescribing additional drugs to elderly
patients unless absolutely necessary.
Children
1 . As paediatricians continually point out, children are
not just small adults. This is especially true for the way
children respond to drugs, both in the nature and the
extent of the response. Not surprisingly, neonates are the
most different and, as children develop, they gradually
respond more like adult patients. Some drugs are speci-
fically contraindicated below a certain age and, of those
medicines that are considered suitable, few have been
formally tested in children. This means that they are
unlicensed for paediatric use.
2. Paediatricians are well aware of these difficulties. Over
the years, they have learnt from experience what are suit-
able drugs and suitable doses for children. Most hospitals
have a paediatric formulary incorporating this experience;
this will often give more age-specific dosing information
than standard references like the BNF. Therefore, always
refer to the paediatric formulary and always ask a paedia-
trician for help if you are at all unsure, or if you wish to pre-
scribe a drug not contained in the paediatric formulary.
Key points
• Children may respond very differently to drugs
compared with adults.
• Most drugs are unlicensed for paediatric use.
• Be guided by the local paediatric formulary.
• Always be willing to seek specialist advice.
Pregnancy
1. The problems with thalidomide in the 1960s have
understandably made doctors very wary about prescrib-
ing drugs when a patient is, or might become, pregnant.
The drug was prescribed to pregnant women to relieve
morning sickness, and resulted in the birth of babies with
aplastic or hypoplastic limb deformities - phocomelia
(Greek phoke = seal + melos - limb; from the resemblance
134
CLINICAL PHARMACOLOGY
11
to a seal's flipper). Many commonly used drugs are
known or suspected to be harmful to the fetus, or have
never been prescribed in pregnancy. There is, however, a
small group of older drugs that accumulated clinical
experience suggests are relatively safe.
2. Often the extent and nature of the harm depends on
the trimester of pregnancy during which the drug is pre-
scribed. Drugs harmful in the first trimester are potential
teratogens (Greek teras = monster + gennaein = to generate),
whereas those prescribed in the second or third trimesters
may adversely effect fetal development or metabolism.
Drugs prescribed late in pregnancy may also affect labour
and harm the child in the peri- and postnatal periods.
3. As far as possible, avoid prescribing any drugs in
pregnancy, but where prescription is inevitable, restrict
yourself to those drugs that are regarded as relatively
safe. On every occasion check in the BNF (Appendix 4)
that the drug is appropriate for the stage in pregnancy of
your patient.
4. What happens if the mother is seriously ill and you
have to prescribe a drug that may harm the fetus? This can
be justified because the well-being of the fetus is secondary
to the well-being of the mother. If you are faced with such
a situation, always try to seek advice from a fetal medicine
specialist in order to minimize risk to the unborn child.
Key points
• If possible, avoid all drugs in pregnancy or in
women who might become pregnant.
• If you must prescribe, specifically check in the
BNF that the drug is considered safe.
• If in doubt, or when a potentially harmful drug
is indicated, seek specialist advice.
Disease
Many drugs are known to have the potential to harm
organs or to exacerbate certain diseases. Potential organ
damage will be listed as a specific adverse effect of a par-
ticular drug. A disease exacerbated by the drug will be
listed in the BNF as a specific contraindication to pre-
scribing the drug.
Liver and kidney disease
1 . The kidneys and the liver are the organs principally
involved in drug elimination. This means that both the liver
and kidney are particularly susceptible to the harmful
effects of drugs (hepatotoxicity and nephrotoxicity). It also
means that pre-existing liver and renal disease may
adversely affect the body's handling of some drugs, leading
to drug accumulation and increased adverse effects.
2. When prescribing hepatotoxic or nephrotoxic drugs,
carefully consider whether the potential benefits to the
patient outweigh the potential risks. If you do prescribe,
monitor for organ toxicity. In those patients with either pre-
existing liver or renal disease, the risks are usually so great
that you should avoid prescribing drugs that are poten-
tially toxic to the affected organ. However, in some cases,
such prescribing is inevitable. If this is the case, make every
attempt to minimize exposure to the drug by reducing dose
and duration of therapy. Rigorously monitor any bio-
chemical changes signalling worsening organ impairment.
3. With pre-existing liver or renal disease, even if you
prescribe drugs that are not directly toxic to the affected
organ, you may still face difficulties due to impaired drug
elimination. In general, reduce the dose and /or frequency
of the prescribed drug. Appendices 2 (liver) and 3
(kidney) of the BNF suggest appropriate dosage reduc-
tions according to the degree of organ impairment.
Key points
• The liver and the kidneys are especially likely
to be harmed by drug therapy.
• Where the potential for harm exists, carefully
monitor for toxicity.
• Pre-existing liver and renal disease often causes
drug accumulation and increase adverse effects.
• Adjust the dose according to the BNF.
• If possible, avoid prescribing potentially
hepatotoxic or nephrotoxic drugs to patients
with impairment of those organs.
• If such prescribing is inevitable, take every step
to minimize additional harm.
Genetic background
It is increasingly recognized that multiple genetic factors
are responsible for much of the individual variability
observed in patients' pharmacodynamic and pharmaco-
kinetic responses to drugs. New drugs are increasingly
designed to minimize such genetically determined vari-
ability but, for the vast majority of patients, we have not
reached a point where a patient's precise genetic make-up
is a factor to consider when prescribing. The only area
where is does matter is when prescribing for patients with
rare single-gene disorders which affect their response to
a wide range of drugs. The best known of these disorders
are porphyria and glucose-6-phosphate dehydrogenase
deficiency (G6PD deficiency). Many drugs are recognized
to aggravate these conditions. If you have a patient with
either of these disorders you should make sure (by check-
ing the BNF) that the drug and dose that you prescribe is
not regarded as potentially harmful.
135
PATIENT ASSESSMENT
Interactions
In practice, it is often drug interactions due to the co-
prescription of other drugs that cause the most problems.
The possibilities for interactions increase exponentially
with each new drug that is added. Drug interactions can
be either pharmacodynamic or pharmacokinetic.
Pharmacodynamic interactions
1 . Additive - where two drugs combine to produce a
greater effect. You may on occasion exploit this
interaction clinically to enhance a desired effect, but
it also can unwittingly produce enhanced toxicity.
2. Antagonistic ~ where one drug cancels or diminishes
the effects of another. Again, you may sometimes
wish to exploit this interaction clinically, particularly
in the case of overdose.
Pharmacokinetic interactions
Any stage of the pharmacokinetic process (absorption,
distribution, metabolism and excretion) has potential for
drug interactions. The most common and important inter-
actions involve drug metabolism and, in particular,
induction and inhibition of the hepatic cytochrome P450
(CYP450) enzyme system. This is a family of the hepatic
enzymes responsible for the metabolism of a wide variety
of commonly used drugs, referred to as CYP450 sub-
strates. These enzymes can be either inhibited or induced
by other drugs.
1 . In the presence of a CYP450 inhibitory the substrate
drug is metabolized more slowly, causing the plasma
levels to rise. Examples of CYP450 inducers are cimetidine,
ciprofloxacin and erythromycin. To compensate, reduce
the dose of the substrate drug.
2. In the presence of a CYP450 inducer, the substrate
drug is metabolized more rapidly, causing the plasma
levels to fall. Examples of CYP450 inhibitors are pheny-
toin, carbamazepine, rifampicin and alcohol. Increase the
dose of the substrate drug to compensate.
3. In practice, interactions due to CYP450 inhibition or
induction are most likely to cause you problems when the
CYP450 substrate drug has a narrow therapeutic index. This
means that there is only a narrow range of plasma con-
centration in which the drug is neither subtherapeutic nor
toxic. Common CYP450 substrates with a narrow thera-
peutic index include theophylline, ciclosporin and war-
farin. Your safe and practical solution with such drugs is
to monitor the plasma level (or International Normalized
Ratio (INR) in the case of warfarin). This monitoring
should be more extensive (i.e. daily) when starting or
stopping CYP450 inhibitors and inducers.
Key points
Drug interactions can be either
pharmacodynamic or pharmacokinetic.
Potential drug interactions are listed in
Appendix 1 of the BNF.
Identify and carefully monitor drugs with a
narrow therapeutic index.
Summary
• Are you aware that even as a surgeon,
prescribing drugs is likely to be a common
and important part of your practice? In
order to prescribe effectively for your
patients, you must be able to select drugs
rationally and use them safely. Despite the
marketing claims, new drugs may not
necessarily be more effective than existing
therapy and will often be much more
expensive. Before prescribing, you should
look for objective and clinically relevant
evidence of benefit from well-designed
clinical trials. New drugs are not always safer
than existing therapy. In fact, precisely
because they are new, there is significantly
less clinical experience than with older drugs.
For this reason, new drugs are subjected to
intensive postmarketing surveillance for
adverse effects that are too rare to have
been detected in prelicensing clinical trials.
• Do you recognize the need to rely on the
hospital formulary when you prescribe, not
on your memory? Consult the BNF unless you
are absolutely sure about a drug. Always use
the BNF when prescribing for difficult
patients, especially those who are at the
extremes of age, pregnant, have coexisting
disease (especially hepatic and renal) or are
receiving other drugs. Always seek to
minimize the number of drugs a patient is
receiving and weigh up carefully the risks
and benefits of using a particular drug. You
should be alert to the problems of drug
toxicity and interactions. If these occur, act
quickly to prevent further harm. In difficult
situations, never be afraid to seek advice
from specialists who have more experience.
Remember, they will be very keen to seek
your help with surgical problems.
136
CLINICAL PHARMACOLOGY
11
Further reading
British National Formulary. Published 6-monthly by the British
Medical Association and the Royal Pharmaceutical Society of Great
Britain, London
Drug and Therapeutics Bulletin. Published monthly, and free to all
NHS doctors, by Which Ltd, London, DTB reviews new and
existing therapies. The articles are concise, independent and well
respected and should be considered essential reading
Ritter JM, Lewis LD, Mant TGK 1999 A textbook of clinical
pharmacology, 4th edn. Edward Arnold, London
Useful links
www.bnf.org British National Formulary
www.nice.org.uk National Institute of Clinical Excellence
www.npc.co.uk National Prescribing Centre
137
Evidence-based practice
J. W. McClenahan
Objectives
Understand the purpose and nature of
valid, important and applicable evidence
to augment personal experience.
Recognize the factors that help and hinder
more widespread application of 'evidence-
based practice' to surgery.
Identify some suggestions for action that
you or your colleagues could take.
Evidence-based practice is:
INTRODUCTION
You already use evidence (Latin e = from + videre = to
see; hence, that can be seen) of many kinds in your sur-
gical practice. The more systematically you can do that,
the better a surgeon you can become. The encourage-
ment given to evidence-based practice (EBP) seeks to
enhance the role that systematic, critical review of valid,
reliable and applicable evidence can play in enabling
you to:
• Perform more appropriate surgery
• Inform patients better about the probable benefits
and risks of surgery for their condition - both
in general, and in relation to their own personal
circumstances
• Enlarge the range of surgical interventions that have
been reliably shown to be worthwhile, by participation
in higher quality research.
WHAT IS 'EVIDENCE-BASED
PRA^
1. Different authors will give varying definitions of
what the phrase means, or even limit it to evidence-based
medicine (excluding other clinical professions such as
nursing or therapies). The following definition from
McKibbon et al (1995) is the one I prefer.
An approach to health care that promotes:
• the collection, interpretation and integration
(into clinical practice) of
• valid, important and applicable
- patient-reported
- clinician-observed, and
- research-derived evidence.
2. There are several points of note about this definition.
It is an inclusive approach to health care as a whole, not a
narrow limitation to research-derived evidence, let alone
just to evidence from randomized controlled trials
(RCTs).
3. It acknowledges the potential validity of patient per-
ceptions, your clinical observations, and the use of judge-
ment to integrate the different sorts of evidence.
4. However, randomized controlled trials remain the
'gold standard' of evidence. They are applicable if the
types of patients included in them adequately match the
real world of your clinical practice.
5. The definition also emphasizes the importance of
building the use of evidence into your routine clinical
practice. Do not see it just as an 'off-line' educational or
research activity done by others. Furthermore, it implies
the development of skills and judgement to decide what
is valid, important and applicable, both to the individual
patient you are considering now, and the whole range of
patients you are or should be treating.
6. Evidence-based practice constitutes an intellectual
revolution in the practice of medicine (in the broadest
sense, i.e. what doctors of all kinds, including surgeons,
do). It has been fuelled in the last decade or so particu-
larly by five interrelated factors:
a. The knowledge explosion - the exponential growth in
published research and knowledge.
b. The particular technique of meta-analysis - pooling
the results of multiple clinical trials to derive more robust
conclusions than any one alone can support.
138
EVIDENCE-BASED PRACTICE
12
_ ■■ [ -.:^-:^,> J . --■■...--.- .v. .■ ■
c. The rapid evolution of systematic review - now a
fomalized, thorough and reproducible (but resource-
intensive) method of finding virtually all evidence on a
topic, grading it by quality and relevance, and summar-
izing the results in a form able to be peer reviewed, and
used by busy clinicians.
d. The organization of the International Cochrane
Collaboration. This links researchers, information analysts,
and practising clinicians worldwide. In the UK, two
centres of particular importance are the Cochrane Centre
in Oxford, and the Centre for Reviews and Dissemination
in York. The collaboration helps to resource systematic
reviews and engages with others in doing so worldwide.
e. Technological developments in knowledge distribution
- particularly CD-Rom and the Internet - which make
knowledge widely accessible easily and relatively
cheaply. Increasingly, this means in the ward, operating
theatre, diagnostic department, outpatient clinic, clinical
staff's own offices and GP surgeries, as well as in libraries,
postgraduate centre and people's own homes.
7. Evidence-based practice aims to improve clinical
effectiveness - doing the right things for the right people
at the right time in the best known way in routine prac-
tice. This means translating the findings of research which
demonstrated efficacy - that there was a difference in a
controlled trial in favour of one intervention over another
- into effective use for a real population of patients.
Achieving clinical effectiveness
requires:
• Professional staff who have up-to-date
knowledge and skills, together with
appropriate attitudes
• Working together in a cohesive and
coordinated fashion within clinical teams
• The support of managers to meet both patient
needs and strategic needs of the organization
(Batstone & Edwards 1997).
For surgeons, this can mean some significant personal
changes or even challenges. Only those with strong indi-
vidual egos seem to become surgeons, and surgery has a
competitive culture. Acknowledging the importance of
teamwork is perhaps easier now than allowing that man-
agers have a valid role to play, but both run counter to
many stereotypes if not the reality of modern surgery.
Some of your behaviours may have to be unlearned!
Weren't we doing it anyway?
1. No conscientious medical practitioner I know wants
to perform badly, and most make strenuous efforts to
keep up to date. So it hurts to be told that your practice
could be improved if you were to change the way you
approach the use of evidence. You think that you already
do the best you can with your limited time and, with help
from your colleagues, you already use evidence - you
were taught to do so by your professors or consultants or
you have been challenged by your up-and-coming
juniors. Well, yes ... up to a point.
2. The reality, as opposed to the aspiration, is that there
are often long delays between the production of convinc-
ing research evidence and its widespread adoption. The
proponents of EBP believe, often with justification, that
these delays could and should be shortened.
3. Things are getting better, however. A historical per-
spective illustrates the point. Prevention of scurvy took
roughly two centuries between the first evidence of effi-
cacy in 1601 (James Lancaster) and its routine adoption by
the British Navy from 1775-1814. In this century, throm-
bolytic therapy after myocardial infarction took about
two decades (from the 1970s to the 1990s) to be acknowl-
edged as appropriate. Only then did it gain general
acceptance as what ought to be done, even though the
application is still uneven (see, for example, Antman et al
1992). Surfactants to relieve respiratory distress syndrome
from hyaline membrane disease for neonates were
adopted even more quickly - in part because their effects
were obvious and dramatic, and in part because they
went 'with the grain' of clinical culture and experience.
What EBP is not but is feared to be
1 . Just cost cutting, or being banned from doing certain pro-
cedures? Many doctors fear that EBP is just an attempt to
reduce costs. They therefore react negatively. However,
careful interpretation of the evidence may suggest that dif-
ferent things be done, some of which may cost more, some
less, and some about the same. Part of your task when you
are a senior surgeon will be to balance the many compet-
ing demands on resources. Evidence of effectiveness must
play a bigger part in future decisions (see Ch. 42).
2. Another reduction in clinical freedom, or 'cook-book'
medicine? Appropriate integration of research evidence
into clinical practice poses no threat to clinical freedom
(using the McKibbon et al definition), except to help you
avoid unnecessary or indefensible mistakes. Is that the
freedom you want to retain?
3. Central diktats will determine local guidelines and proto-
cols and 'the way we do things here'? These should rather be
determined locally, but using centrally collated and
validated evidence. By establishing more clearly your
own and your colleagues' understanding of what is
known with reasonable certainty, based on research evi-
dence, experience and patient feedback, you can make
139
12*
PATIENT ASSESSMENT
Table 12.1 Examples and issues
Nature of evidence
Evidence convincing,
widely accepted, but not
universally applied
Evidence readily
available but not sought
Evidence sought, but not
locally accessible at the
relevant time or place
Evidence actively
sought, not found,
equivocal or
disputed
Examples
Early thrombolytic
therapy for AMI
Which surgical patients
benefit from DVT prophylaxis?
Whom should we treat
for atrial fibrillation?
As above, and ...
Adjuvant therapy
following surgical removal
of cancers
When should we remove
catheters after paediatric
cardiac surgery?
Issues
(Often mistaken) belief that 'we already do it here'
- [ocal and national audits often show otherwise
Achieving organisational change to allow it
Shifting professional attitudes to seeking evidence
CPD (continuous professional development)
Interpretive skills {critical appraisal training)
Organizational and technical infrastructure
Information and library facilities and staffing
Technical skills training
Establishing effective local guidelines, and local
audit or research projects
Feedback to national R&D priority setting or
local academic centre
commonplace practice more consistent, and higher quality
easier to deliver, audit and sustain. This leaves more, not
less, freedom and time to use your judgement in areas
where the circumstances are not routine, the research-
based evidence is absent or equivocal, or the patient's indi-
vidual preferences are uniquely out of the ordinary.
4. Just for doctors, or just for clinical staff? Evidence-
based practice is as relevant for patients and their fami-
lies or carers, and for managers, as it is for you. Media
attention and the internet now make much more of the
evidence widely available. Sessions with non-clinical
staff, including managers and non-executive directors
from NHS organizations/ demonstrate that they can
quickly and intelligently appraise even technical papers
against systematic appraisal criteria. They can reach clear
conclusions about the strength and interpretation of the
evidence for themselves (from my personal experience
with such groups at the King's Fund).
Who needs information on evidence-
based practice?
Patients to discuss options and risks with you.
Professionals to improve their practice.
Providers to improve effectiveness for their
organizations.
Purchasers, now primary care trusts (PCTs) in
the NHS; more generally, commissioners of
health care, to obtain the best quality service
they can afford.
Public for assurance that all of the above is
happening properly in their interests.
HOW CAN EVIDENCE MAKE A
DIFFERENCE?
1. Evidence can impact practice in several different
ways, and what needs to be done to improve things
depends on the nature of the evidence, and what sort of
barriers prevent its use. Examples (not exhaustive) are
shown in Table 12.1.
2. What helps or hinders change? The 'change equa-
tion' (adapted from Beckhard & Harris 1987) is shown in
Figure 12.1. You need to pay attention to all four boxes
to maximize the likelihood of successful use of evidence
to change practice. Acknowledge that you may be able to
work on the perception that others have of the proposed
Perceived
power of
vision
Perceived pain
of present
Perceived
feasibility of
first steps
Perceived pain
of change
Fig 12.1 Beckhard's change equation. In order to change practice you need to take account of all four boxes. Present
a clear, persuasive view of how things might be, show the present drawbacks, devise feasible initial changes and
minimize 'discomfort' of change perceived by those affected
140
EVIDENCE-BASED PRACTICE
12
changes as well as the 'real' content of the change, as, for
them, their perception is the reality.
3. To succeed:
a. Present a clear and persuasive view of how things
might be (the vision) in terms relevant to the intended
audience.
b. Show the drawbacks of the present circumstances
(perhaps unsatisfactory or even dangerous), and ensure
that other people become as uncomfortable with it as you
are yourself.
c. Devise some initial changes that people see as
feasible to get started (so make thern as easy to adopt as
possible).
d. Minimize the discomfort of the change as it will be
perceived by individuals or groups affected.
4. Changing clinical practice is a multistage process. It
does not happen all at once, and different influences work
at different stages of people's readiness for change.
Key point
• Do not presume that a rational argument,
clearly and forcefully presented, will of itself
predispose people to change, especially if they
are not yet emotionally ready even to believe
it is necessary at all.
5. Figure 12.2 shows one model of individual change
(based on Prochaska & DiClemente 1984) that may be
helpful in understanding where you and your colleagues
stand. It is crucial to acknowledge the importance of the
early stages - initial awareness of the possibility of change
and recognition of a need to change. This can often take
time (months, or occasionally years) to work through.
Where the major personal block is an emotional one,
restating the rational case ever more forcefully is posi-
tively unhelpful. Ask rather than tell, and try to find out
what emotion is being triggered by your proposal (or
your own reaction to others' proposals) and seek to deal
with that first.
6. Organizational change is a slower process than you
expect - be patient. You may be used in your surgical
team to making decisions and seeing them implemented
very quickly or even instantly, if the power to change lies
wholly within the surgical team. However, much of the
improvement in clinical practice suggested by research
evidence requires change on a broader organizational
front. Many people with different professions, personal
backgrounds, beliefs and values may have to be per-
suaded. Evaluation of change 'in the field' in response to
evidence suggests four major hindrances to change at a
scale larger than a single clinical team:
a. Getting momentum going. Raising awareness and
recognition of the need to change takes time, patience,
and repeated application as the 'cast of characters' is con-
stantly changing in the hectic pace of NHS reorganization.
b. Staff turnover. Original sponsors of change may leave
the organization.
c. Action. Getting guidelines agreed and accepted is
more difficult than most people initially believe is possible.
d. Implementation and maintenance. If you think getting
guidelines agreed is the hard part, think again. After that
is when the most difficult (but ultimately rewarding) part
really starts. To engage others more widely beyond the
enthusiasts, you or a small group around you, need yet
more patience, careful planning, wide consultation and
Emotional
- engagement
- acceptance
Rational
- clarification
- diagnosis
Fig 12.2 A model of individual change
141
12
PATIENT ASSESSMENT
listening, and adequate resource to see your proposals
into widespread and sustained use. Grol (1997) has a
useful review of the different types of approach that could
be adopted, and the evidence for their effectiveness.
7. You need other sorts of information, some relatively
obvious, others perhaps unexpected:
a. Local demographics (population size, density and
distribution), and prevalence of the disease or condition
of interest. How many people does it affect? How
seriously?
b. Actual local practice. Audit of current practice, and
open discussion with colleagues may reveal unexpected
differences between what you believe should happen or
think is already happening, and what actually does
happen.
c. Patients' and service users 7 views. Have you asked
them, or looked for previous evidence of their views, rather
than what you think their views are, or ought to be?
d. Understand the organizational context. How does
the diagnostic, treatment and care process actually work
at present, and who would be affected by proposed
changes? How are referral decisions influenced? How
could you change that?
e. Local 'political insighf . Who has a stake in this
process? What do they think about the issues? What else
is on their agenda that may help, or hinder, progress in
the direction you want?
f. Where might resources be obtainable? Change is
unlikely to be completely neutral in resource terms, such
as time, energy, money and facilities. How may they be
freed up to pump prime change, or where can additional
resources be sought with some chance of success?
Key points
• We can all identify what is wrong.
• Merely stating problems is ineffective. Devise
solutions.
• The goal is not just devising solutions but
implementing them.
^WHELPS?
1 . In our own research into the process of implementing
evidence-led change in North Thames region (Smith
& McClenahan 1997, 1998; Haines and Evans 2000;
Wye and McClenahan 2000), six factors seem to make
progress more likely:
a. Support from both managers and clinicians at a
senior level
b. Adequate resourcing in relation to the scale of
ambition
c. A project management approach, with clarity
about lead roles, and clarity of objectives for the
change process on a realistic scale (neither
overambitious nor too modest)
d. Having, or putting in place, the right
organizational infrastructure to support clinical
service improvements
e. An understanding of change management as a
process
f. Closing the loop properly - auditing whether
clinical processes have changed to match those
associated with efficacy in a research environment.
It is usually not possible or necessary to audit
outcomes themselves — that was what the research
was about.
2. Depending on your present level of seniority and
influence, consider some of the following ways of
making a difference:
a. What is your own attitude to the possibility of
improvement to your own practice? Talk it over
with colleagues. Analyse your emotional reactions
as well as the practical and rational ones.
b. Access information sources (particularly the
Cochrane database (CD-Rom), Medline, CINAHL
and the internet) and learn how to make use of
them. Encourage all your staff to use them. Get
help from others with the relevant skills.
c. Seek local training (if you have not already had
some) in critical appraisal - the process of
reviewing published research evidence to assess
its quality and relevance to your own patients'
circumstances. Practise it in your routine
work.
d. Try to make or reinforce connections between the
clinical governance or clinical effectiveness
committee (or its local equivalent) and its
subgroups; clinical audit; library and information
services; multidisciplinary team working;
education and training; Continuous Professional
Development/ Continuing Medical Education;
guideline development; and patient information
provision (see Chs 42, 43).
e. Seek management support for implementing
desired change processes: in your own team;
across departments; for common clinical
conditions; and across organizational boundaries
with primary and tertiary care and where
relevant, social care and support organizations.
f. For the real enthusiast: take part in a systematic
review of an area of practice that interests you.
142
EVIDENCE-BASED PRACTICE
12
Summary
♦ Recognize that evidence-based practice
encompasses not just the application of
randomized controlled trials but all
aspects of health care.
* Question your practice and consider how
much is justifiable on reliable evidence.
• Can you offer your patients firm evidence
on which you base your advice?
• Do you accept that you can enlarge your
range of surgical interventions by seeking
trustworthy evidence and by participating
in high quality research?
References
Antman EM, Lau }, Kupelnick B, Mosteller F, Chalmers TC
1992 A comparison of results of meta-analyses of
randomized control trials and recommendations of clinical
experts. Treatments for myocardial infarction. JAMA 268:
240-248
Batstone G, Edwards M 1997 Challenges in promoting clinical
effectiveness and the use of evidence. In: Harrison A (ed.)
Health care UK, 1996/7. King's Fund Policy Institute, King's
Fund, London
Beckhard R, Harris RT 1987 Organizational transitions:
managing complex change, 2nd edn. Addison Wesley,
Reading, MA
Grol R 1997 Beliefs and evidence in changing clinical practice.
BMJ 315: 418-421
Haines A, Evans D (eds) 2000. Evidence based change in
healthcare. Churchill Livingstone, Oxford
McKibbon et al 1995: see Useful links
Prochaska J, DiClemente C 1984 The transtheoretical approach:
crossing traditional boundaries of therapy.
Dow Jones-Irwin, Homewood, IL
Smith L, McClenahan JW 1997 Putting practitioners through the
paces: initial findings in our evaluation of putting evidence
into practice. King's Fund and North Thames R&D
Directorate, London
Smith L, McClenahan JW 1998 Snakes and ladders: levers,
obstacles and solutions to putting evidence into practice.
King's Fund and North Thames R&D Directorate, London
Wye (nee Smith) L, McClenahan JW 2000 Getting better with
evidence. King's Fund and North Thames R&D Directorate,
London
Useful links
hiru.mcmaster.ca/hiru/medline/mdl-ebc.htm McKibbon K,
Wilczynski N, Hayward RS, Walker-Dilks C, Haynes RB 1995
The medical literature as a resource for evidence based care
www.kingsfund.org.uk/eLeadership/html/publications.html
King's Fund Publications, London
www.doh.gov.uk/ntrd/pdf/getbtr.pdf Department of Health,
London
143
Decision making
R. M. Kirk, K. Cox
W
Objectives
Recognize the complex, multiple,
interacting factors that need to be taken
into account when making a decision. Even
though you may not be able to evaluate
all of them, do not ignore them.
Good decisions demand the best available
evidence. Critically search out and use
discriminant information in preference to
equivocal and dubious evidence.
Decisions are valid only at the time they
are made. Be prepared to revise them if
the circumstances change.
Remember that your patient must be fully
informed, and understand the information,
in order to participate in the decision
making and give informed consent.
Furthermore, your patient's evaluation of a
successful outcome may not be the same
as yours.
Good surgery is 25% manipulative skill and 75% decision
making.
Adapted from the distinguished
American surgeon F. C. Spencer
INTRODUCTION __ ^ _ __
This chapter forms the fulcrum of the book. What has
gone before is the knowledge and evidence that you
should have available. What follows are the actions and
consequences of the decision or decisions that you take.
As a surgeon you cannot merely follow a set of rigid
instructions. You are a professional who searches for
information, appraises it, makes decisions, acts on them,
monitors the outcomes and accepts responsibility for
them to your patients, your peers and your own con-
science. However, decision making depends on a multi-
plicity of factors, many of which may be unknown or
even unknowable. Some are not susceptible to scientific
or statistical evaluation, and because they are disparate,
they cannot be listed in a ranked sequence of graded
importance. In the past there was little appreciation of
risk analysis, cost effectiveness and the patient's assess-
ment of quality of life following treatment.
Our challenge is to identify the important, discriminant
elements from the inconsequential ones, but oversimpli-
fication is dangerous. You must not concentrate on the
components in isolation but consider the patient as a
whole, not merely as an aggregation of individual parts.
The whole has qualities beyond those of the parts. The
term Gestalt (German = form, build, fashion), was coined
in 1890 by a group of German psychologists to denote
experiences that require more than basic sensory capaci-
ties to comprehend.
Within a simple linear system the whole behaves pre-
cisely and predictably as the sum of the parts. A change
of one factor produces a consistent, predictable effect. We
are composed of multiple biochemical, cellular, physio-
logical and psychological systems which interact by
means that include biochemical and neuroendocrine
feedback loops. Within such a complex system a change
in one unit may produce unforeseeable, seemingly capri-
cious, collective behaviour. The emerging 'complexity
theory" takes account of the fact that complicated, self-
organizing systems continuously adapt to and change
their environment, but in ways that are impossible to
predict. The theory is not yet a fully developed science,
but seeks to identify, with the intention to predict, the
emergence of characteristics that are not present in the
individual components. For these reasons, reliable clini-
cal decisions cannot be made by adhering to rigid rules.
There is often an element of uncertainty (Plsek &
Greenhalgh 2001, Wilson & Holt 2001).
Data derived from linear systems is often 'Yes or No/
and 'Black or White/ In complex biological systems it is
more frequently, 'Perhaps, depending on a number of
factors/ and 'A shade of grey/ We do not judge the evi-
dence before us with open minds because we are already
conditioned by our previous knowledge and experience.
144
DECISION MAKING
13
Our subjective assessment may differ from that of others
with a different knowledge background and experience.
Our own judgement may vary resulting from a recent
success, or series of disasters. This is not a defect in us; we
learn to recognize patterns and make tentative prejudge-
ments - 'prejudices'. Prejudices are reprehensible only if
they are inflexible.
Some surgeons are more successful than others at
making correct decisions. Their results are superior to
those of others, not only following operation when their
superior skills can be invoked, but also in the one-third
of surgical cases that are treated conservatively. They
usually cannot give a rational explanation for their judge-
ment and often attribute it to a "gut feeling'. Such sur-
geons appear to anticipate and evaluate the possible risks
instinctively. Perhaps they take time to consider all the
possibilities, rather than settling on the first course that
presents itself. We surgeons like to think of ourselves as
men and women of action, that is, 'decisive 7 . Not all deci-
sions need to be taken instantly. The increasing require-
ment to display the arguments for or against the possible
courses of action to colleagues and to patients should
have a beneficial effect on decisions.
It is remarkable that most of our major decisions are not
made rationally. Consider your own life decisions. Can
you logically defend your choice of profession, your life
partner, or always justify the clinical judgement to ask
advice, enlist assistance, conclude that you must proceed,
or relinquish responsibility to someone better able to care
for your patient?
Previous generations of autonomous surgeons made
decisions and presented them to their team and patients
without discussion. Attitudes have gradually undergone
a transformation. As a result, we first make our assessment
on the basis of our training, experience and access to
scientific and professional information. We consult other
members of our team and specialist colleagues. When
dealing with certain conditions, such as complex tumours,
we form specialized groups in order to bring together all
relevant experts. We can now offer an appraisal for dis-
cussion with the patient, in terms that are comprehensible,
in order to reach a mutually agreed course of action and
receive informed consent (see Ch. 14). This entirely appro-
priate change has, of course, added yet greater complex-
ity to the factors that must be taken into consideration. The
change has been from what was a virtual statement of
intent, into a complicated group negotiation.
Surgeons formerly dealt with a wide range of condi-
tions and a single surgeon might see relatively few cases
of any particular condition, making it difficult to make
judgements for the future. Individual decisions may be
impossible to assess in retrospect. The outcome could be
poor in spite of good judgement and expert care, owing
to factors that are unknown, unmeasurable or over which
there is no control. Conversely, a robust patient may
survive incorrect or inadequate management.
As a result of specialization, the formation of teams,
specialist groups, and national and international
exchange of information, large numbers of similar cases
can be accumulated and the outcome following different
methods of treatment can be compared.
The initial assessment and decision resemble the strat-
egy (Greek stratos = an army + agein = to lead) of an army
general. He is not, though, able to predict the response of
the opposing general to his planned moves, so must
closely observe and react by rearranging his plans; this is
tactics (Greek tactikos from tassein = to arrange, hence
rearrange). Very few decisions in life are once and for all.
ESSENTIALS OF SURGICAL DECISION
MAKING
Information
1 . Since you cannot incorporate all the information into
a balanced judgement, you must discriminate by choos-
ing what is relevant and reliable, what must be borne in
mind, what can be left out of consideration for the time
being, and what can be rejected as invalid or irrelevant.
2. Can the published literature be applied to your
patient? No two patients are exactly the same and some
factors may exclude your patient from being comparable
with the tightly selected patients assessed in statistical
trials. However, some of the aids to decision making may
be less constrictive (see later).
3. Following carefully considered initial judgement,
determine to anticipate and react to subsequent changes
so you do not endanger recovery.
4. Determine to monitor, analyse and record the cir-
cumstances and outcome of your strategic planning and
subsequent management, so you can in future adjust your
decisions.
Joint decision making with the patient
1. First decide what is the professional opinion you
will offer the patient. You should review the possible
methods of management, with the benefits and risks.
Patients expect you to have your facts marshalled, other-
wise you cannot give them a clear picture. Informed
consent (see Ch. 14) implies that patients are well
informed.
2. Match your explanation to patients' comprehension.
At all costs avoid scientific terms or jargon that are likely
to confuse rather than instruct them. From time to time
check that they understand you by asking them to tell you
how they view the situation (see Ch. 47).
145
131
PATIENT ASSESSMENT
3. Although patients wish to participate, you are the
professional adviser. How you pass the information
inevitably influences their judgement.
4. Many patients faced with the presence of disease and
the necessity for treatment, including perhaps an operation,
are not in the best state of mind to make important choices.
For this reason, whenever there is time, state the various
possibilities and likely outcomes as simply as possible, then
suggest that the patient returns after an interval to ask any
supplementary questions and then reach a decision.
5. As you point out the consequences of the proposed
management, your measures of success are not necessarily
in line with those of your patients. Powerful fears for many
patients, beyond length of survival, are constant pain, loss
of the ability to care for themselves, and loss of dignity.
However, it is often difficult for them to anticipate what will
be their reaction to the effects of the proposed management.
6. Recognize your patient's right to ask for treatment
that differs from that advised by you but do not agree to
treatment that is harmful, ineffective or offends against
your own moral code.
Cost effectiveness
This was often ignored in the past when making deci-
sions, the only consideration being for what treatment
best met the patient's needs. It is now openly accepted
that in no society can treatments be offered without
taking into account the economic implications, and the
likely cost-benefits of other treatments (see Ch. 44).
priority, and that you reconsider the order from time to
time. Try not to attempt too many tasks at once - but in
an emergency be willing to abandon a less important one
and undertake one that is urgent.
2. We hope to select available information with open
minds but there is a temptation to seek and select evidence
that confirms our prejudice. Make a deliberate effort to
stand away from the problem so you may become aware of
incongruities that make you revise your first assumption.
3. Very few questions can be answered positively - 'Yes
or No/ or 'Black or White'; the particular shade of grey is
a subjective opinion.
4. All clinical decisions demand some simplification of
the multiplicity of factors, but do not lightly leave anything
out of consideration. Albert Einstein stated, 'Everything
should be as simple as possible, but not simpler'. The dif-
ficulty is in allotting importance to disparate influences on
diagnosis, extent of disease and management options.
5. Measuring individual aspects separately does not
provide a complete picture. You must also look at the
patient as a whole.
6. It is usually accepted that experience leads to
better decision making. We learn to recognize familiar
patterns. However, there is a temptation to identify
resemblances early and overconfidently, thus not fully
checking the remainder of the available evidence. Two
similar clinical situations are rarely identical, and so
may call for different action.
EMERGENCIES
Key points
Prepare yourself; learn from experience,
experts, surgical literature and other sources of
evidence-based information.
Do not overburden yourself with unreliable,
irrelevant data - favour proven, discriminant
facts.
Do not obsessively limit your study to one
possible choice. Assess the benefits and risks of
other management options.
Follow your patients: study the outcomes in
the hope of improving your results.
A sudden, urgent, unexpected incident puts great strain
on your judgement. You are often put under pressure to
'do something', and 'doing something' may be inappro-
priate. Although this is an emergency (Latin e = out of +
mergere = to plunge, to thrust suddenly), it does not
inevitably demand instant action. Except for standardized
situations like cardiopulmonary arrest, be willing to take
sufficient time to assess the situation and make a decision.
Is the required action within your capability, and is the
required assistance and equipment available? If the action
is beyond your normal capability, but if there is no one
more capable, are there any effective measures you can
perform? In such circumstances, when there is no alter-
native, people have achieved near miracles.
OBSTACLES TO GOOD DECISION
MAKING
1 . Clinicians are rarely able to concentrate on a single
problem. You always have many tasks to fulfil. Make sure
that you allocate each one a ranked place in order of
AIDS TOJJEO^^
Clinical skills
1. In case of difficulty, when there is no urgency, be
willing to defer making a decision and give yourself time
146
DECISION MAKING
13
to think about the possibilities, discuss it with a trusted
colleague, and refer to the literature to check the recent
reports.
2. In an emergency be willing, if time permits, to
review the features after a short interval - they sometimes
change dramatically.
3. In case of doubt, ask a colleague who has no com-
mitment to the patient's outcome, whose opinion you
respect, to carry out a fresh and independent examination.
Educational value
1. Use every opportunity to learn by studying how
each decision is reached and how it can be justified.
On many surgical firms it is common practice for
the senior surgeon to make an on-the-spot decision,
which is not questioned. Complex, controversial
problems should be used as valuable educational aids.
Each member of the team studies the literature, considers
the possibilities, and reaches and justifies a conclusion at
a meeting chaired by the senior surgeon. When each
participant has presented a well-argued viewpoint, try to
reach a consensus judgement. Subsequently, review the
outcome to decide if the decision was correct, or whether
a different conclusion should be reached when a similar
case is encountered. At intervals, review all the patients
who have been treated for the condition under
consideration (see Ch. 42).
2. Can useful guidelines be drawn up for future con-
sultation - and regular review?
3. How do the results compare with those from other
units?
RISK MANAGEMENT
ii^iv&t^s^^^
Organizational risk management
1. Do not make your decision solely on clinical
grounds. Surgical treatment demands a wide range of
complex facilities. Your own competence, and confidence
that the patient can withstand the proposed procedure,
are not the only considerations when judging how to
proceed.
2. Before investing in an unknown business, some
commercial firms ask for a report on its perceived
strengths, weaknesses, opportunities and threats
(SWOT). This stimulates the informant to stand away
from individual problems and consider the overall
picture. The threats in surgical decision making do not
merely refer to patient survival versus recovery. There
are many possible sequelae, such as unexpected findings,
absence of vital staff, and failure of some important
equipment. In making your decisions, ensure that you
consider all the possibilities and take precautions against
possible difficulties.
3. There are many aspects to risk management. Many
of the procedures carried out have health and safety
implications. Make sure that you know the correct pre-
cautions with electrical, radiation and other equipment
(see Ch. 17). Ensure, when making your decision, that
your requirements will be adequately met.
4. Do you have the required support of expert staff,
with necessary equipment such as intensive care beds
fully staffed?
Key points
• Surgeons previously accepted serious support
deficiencies, adding to the risk, because there
was no alternative.
• Do not undertake procedures when the
circumstances are not ideal, except in dire
emergency.
Clinical risk management
1 . Prognostic risk scores. A number of scoring methods
have been proposed so that the chances of recovery can
be estimated. In this way the success of various methods
of treatment can be compared. These methods were
developed for comparing groups rather than individuals
but their use has often been extended to assess individual
risks.
a. The American Society of Anesthesiologists (ASA)
produced a five-grade risk assessment, on to which can be
added the effects of age, operative severity, respiratory,
cardiac and nutritional state.
b. The Acute Physiology and Chronic Health Evaluation
(APACHE) score is helpful in assessing the outcome for a
group of patients but less so for individual cases. In the
United Kingdom the modification, labelled APACHE II, is
most commonly used.
2. The Physiological and Operative Severity Score for the
enumeration of the Mortality and morbidity (POSSUM)
and Portsmouth modification (P-POSSUM) are particularly
valuable for assessing the operative risks in the two- thirds
of patients who require surgical treatment (Jones & de
Cossart 1999). They incorporate an operative severity score
as a predictor of outcome. Proposed use of POSSUM and
P-POSSUM for comparative audit is deprecated (Bann &
Sarin 2001). Trauma and sepsis scores can also be calcu-
lated. Biological age offers a better assessment of risk than
does calendar age (Farquharson et al 2001).
147
PATIENT ASSESSMENT
^4$^v3?&^^^^
TYPES OF DECISION
Codified decisions
If facts and experience can be measured and then com-
pared with the findings in other similar situations, it
becomes possible to make decisions for future guidance
when faced with similar problems (Wyatt 2001). As a
result of reviewing series of cases / various standardized
methods of management have been devised. If the
problem complies with previously assessed cases, a plan
can be developed so that succeeding problems can be
dealt with according to predetermined directions:
• Algorithm (Arabic al-Kwarazmi, modern Khiva in
Uzbekistan). In this city lived the 9th century mathe-
matician Abu Ja'far Mohammed ben Musa, who devel-
oped a rule for solving a problem in a finite number of
steps. The sequential steps are followed automatically
and algorithms are embodied in computer software.
• Protocol (Greek protos = first + kolla = glue; a glued-on
first leaf of a manuscript). Among other things it is a
set of rules, or uniform method, of approaching a
problem, sometimes displayed as a flow chart, with
alternative pathways to treat differing circumstances
and outcomes.
• Guidelines offer a viewpoint agreed by an authoritative
person or body They are not as reliable as evidence
based on prospective, double-blind, trials that have
produced statistically significant results; however, they
are less rigid. The issuing of guidelines is contentious
because those who, for good reason, do not follow the
guidelines, may feel vulnerable to criticism if the
outcome in a particular case is poor. Because guidelines
vary in their power, they may be graded (Harbour &
Miller 2001).
• Decision trees are valuable in displaying and evaluat-
ing possibilities and outcomes. Risks of treatment
mortality and long-term survival are available for
many conditions in the medical literature or from
reviews such as the Cochrane collaboration or on the
internet. In the future the National Institute for Clinical
Excellence (NICE) will issue reports on a wide range of
treatments.
All the probable outcomes should add up to 1
(Fig. 13.1). In addition to the objective outcome
measure, there is a subjective value, called a "utility/
your evaluation and the patient's may differ - but it is
the patient's valuation that must prevail. However, it
may be difficult or impossible for the patient to antici-
pate the effect of the outcome on the quality of his or
her life, often calculated as quality adjusted life years
(QALYs). The quality of each year of life is subjectively
judged by the patient. A year during which the patient
enjoys full fitness is 1 QALY. A 2 year survival, each
judged to have provided 50% of full fitness and enjoy-
ment, is also judged to be 1 QALY. You may be able to
advise, or put the patient in contact with others who
have been treated for the same condition. The sum of
the probability and utility produces a figure for the
'expected utility 7 , and the course of management
earning the highest mark is the preferred one (Fig. 13.2)
(Birkmeyer & Welch 1997).
Although the objective evidence for all the possible
courses of action may not be available, forming a deci-
sion tree is a valuable exercise for displaying the range
of possibilities.
Surgical
oO
Malignant condition
^
f.
Improved
p = 0.6
1 ^
>=►
Same
p=0,3
^==►1
Worse
p = 0.1
p=!>
Improved
p=0.3
)=>
Same
p = 0.5
U
Worse
p= 0.2
Fig. 13.1 A simple decision tree comparing the probability (p) of outcomes for two methods of treating a malignant
condition. ■ Denotes a decision node; O denotes possible outcomes.
148
DECISION MAKING
13
=>
Surgical
r^
Improved
^>o=*
p= 0.6
Utility Expected utility Sum
10
5
0.6x10 = 6
0.3x5 = 1.5 }
0.1x0 =
7.5
Radiotherapy b
Improved
Same
Worse
p = 0.3
P-0-5|
p = 0.2
10
5
0.3x10 = 3
0.5x5 = 2.5
0.2x0 =
5.5
Fig. 13.2 The utility (subjective benefit or disability) resulting from the outcome is graded from 10 (good) to (bad).
The product of probability (p) and utility is the 'expected utility'. Finally, the sum of the expected utilities for each
decision can be compared. The course scoring the highest mark is the preferred one, in this case surgery. ■ Denotes a
decision node; O denotes possible outcomes.
^
Key point
• Review guidelines, algorithms, protocols and
decision trees from time to time (Fig. 13.3).
They may require modification in the light of
audited results of previous outcomes,
comparison with published data from other
units, and advances in diagnosis and
management.
Personalized decisions
1 . Many decisions are complex and cannot be made in
a standardized, codified manner. The condition may be
complicated by cofactors, or may have unusual features.
The decision is unique and may be challenging or even
controversial. Some of the factors may be indefinable and
difficult to weigh in the balance. It is in such circum-
stances that opinions differ between specialists because
of individual selection of evidence and the importance
given to it.
Examine
Investigate
Assess
=>
o
PROBLEM <=
Surgeon < 3
+
Team (Anaesthetist etc)
DETERIORATION OR
FAILURE TO RECOVER
HZ
ACTION
£
MONITOR
$> Co-factors
Patient
DECISION j^»
<3=
Risk analysis
Cost effectiveness
Algorithm
Protocol
Guidelines
Decision tree?
RECOVERY
Fig. 13.3 Some of the complex, and disparate, considerations to be taken into account when making a decision,
acting on it and monitoring the result.
149
PATIENT ASSESSMENT
2. Knowledge that cannot be transferred verbally can
be labelled 'tacit/ (Wyatt 2001) (Latin tacere = to be
silent). The decision-maker cannot justify the decision in
scientifically acceptable terms. Some surgeons produce
better results than average; they may be technically
superior but an alternative or additional reason is that
they make a higher proportion than average of correct
decisions.
3. The likelihood is that good decisions are made by
an intuitive selection of the most important factors,
while discounting less important factors. Combined
with this is the selection of treatment that is appropriate
for that particular patient. Some surgeons say, T know
what I can get away with'; others are overoptimistic of
their ability to achieve success with poor risk patients
subjected to overaggressive treatment. Other surgeons
are dissuaded from embarking on potentially highly suc-
cessful treatment for fear of failure, or of 'spoiling' their
results. Such reluctance may increase if the outcomes for
individual surgeons or units become accessible to the
general public.
4. Personal experience, especially of rare problems, is
a powerful influence on decisions, so that senior sur-
geons are usually trusted to deal with them. A particular
example is the recognition of postoperative complica-
tions, or of failure to recover as expected; if you are in-
experienced, you do not know how to recognize what is
normal and what is important. In some cases the experi-
enced colleague may be unable to explain a suspicion,
but may just acknowledge a 'gut feeling' that all is not
well.
Key point
It is wasteful of resources for every decision to
be made on a one-to-one basis if the problem
conforms to a standardized pattern for which
guidelines, algorithms, protocols or decision
trees have already been published. The guides
must be regularly reviewed and authenticated.
Unless there is additional evidence, or
circumstances that differ from the
standardized description, hesitate to make a
heterodox decision. Will you be able to justify
it to your patient, your colleagues, and to your
own conscience, if there is an adverse
outcome?
Summary
• How many influences and factors can you
list that must be brought into the process
of clinical decision making? How many of
them can be scientifically assessed? Can
you rank them in terms of their
importance of effect on outcome?
• What are discriminant features? Can you
list such features for some of the common
clinical conditions with which you deal?
• Do you know the published outcomes for
three common conditions? Where would
you look for the information in order to
create a decision tree?
• Can you name examples of decisions for
which there are well-authenticated
pathways to follow, and also those that
are exceptional and demand your best
judgement - or the advice of an
experienced expert?
• Can you recall the important
considerations necessary when informing
patients and making joint decisions with
them?
• As a surgeon committed to taking
decisions and acting upon them, how
would you justify demanding the facilities,
throughout your career, to acquire and
critically evaluate new information, both
verbally and by association with leading
colleagues?
References
Bann SD, Sarin S 2001. Comparative audit: the trouble with
POSSUM. Journal of the Royal Society of Medicine 94: 632-634
Birkmeyer JD, Welch HG 1997. A reader's guide to surgical
decision analysis. Journal of the American College of
Surgeons 184: 589-595
Farquharson SM, Gupt A, Heald RJ, Moran BJ 2001 . Surgical
decisions in the elderly: the importance of biological age.
Journal of the Royal Society of Medicine 94: 232-235
Harbour R, Miller J 2001 . A new system for grading
recommendations in evidence based guidelines, BMJ 323:
334-336.
Jones HJS, deCossart L 1999. Risk scoring in surgical patients.
British Journal of Surgery 86: 149-157
150
DECISION MAKING
13
Plsek PE, Greenhalgh T 2001. The challenge of complexity in
health care. BMJ 323: 625-628
Wilson T, Holt T 2001 Complexity and clinical care, BMJ
323: 685-688.
Wyatt JC 2001. Management of explicit and tacit knowledge.
Journal of the Royal Society of Medicine 94: 6-9
Further reading
Cox K 1999 Doctor and patient: exploring clinical thinking.
Phase 3: Deciding what to do. University of New South
Wales Press, Sydney, pp 185-270. This thoughtful readable book
is an account of the way in which we think and make our
decisions
O'Connor AM, Rostom A, Fiset V et al 1999 Decision aids for
patients facing health treatment or screening decisions:
system review. BMJ 319: 731-734. Patients may need help when
they are deciding between treatment options
Polanyi M 1958 Personal knowledge. Routledge and Keegan
Paul, London. References and explanations throughout of tacit
knowledge and acquisition of skills. A masterpiece from a
Hungarian-born polymath, investigating the special wisdom of
the expert. It explores those skills that cannot as yet be verbalized
but need to be passed on during the master-apprenticeship
relationship
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153
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Consent for surgical
treatment
L Doyal
Objectives
Recognize the need to establish trust and
confidence in patients under your care.
Understand that a signature on a consent
form is not legal proof that informed
consent has been given.
Realize that you must warn patients of the
hazards as well as the benefits of surgical
treatment.
Identify and deal appropriately with
difficulties in gaining consent. Respect the
confidentiality of your dealings with
patients.
the legal right of women to choose to have an abortion
under certain circumstances is regarded as immoral by
those who believe that a fetus has the rights of a born
child. In short, our beliefs about who has a right to what
inform our decisions about how we should act toward
others if our actions are to be deemed morally, and
perhaps legally, acceptable.
The general right of surgical patients to self-
determination can be subdivided into three further rights:
to informed consent, to the truth and to confidentiality.
The latter two clearly follow from the first. Choices cannot
be properly informed on the basis of deception and cannot
be respected if what patients deem private is made public.
Therefore, it is the principle of informed consent itself
which is fundamental and on which both the mortality
and the legality of good surgical practice partly depend.
INTRODUCTION
For surgery to be successful, there must be a relationship
of trust and confidence between you and your patients,
otherwise they are likely to be reticent in presenting for
treatment or in divulging the detailed personal informa-
tion required for recording accurate case histories and
making successful diagnoses. Aside from the belief that
their care will conform to a high clinical standard, the
trust of patients also depends on their belief that their
autonomy will be respected - that they will have the right
to decide their own medical destiny, whatever anyone
else may think.
Moral rights are like that. They indicate claims that
individuals can legitimately make against others who
have corresponding duties to respect those claims. To the
degree that we believe that the right to make such a claim
exists, then those on whom it is properly made must
respect it and act accordingly, irrespective of their prefer-
ences. Examples of often-cited moral rights emphasize the
entitlement of individuals to self-determination - to be
able to pursue life goals and perceived interests in ways
in which the individual has chosen - provided that others
are not harmed in the process. Moral rights might or
might not be backed up by the force of law. For example,
THE MORAL IMPORTANCE OF
INFORMED CONSENT
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Key point
• The moral unacceptability of anyone exercising
unlimited power over others is at the heart of
many of our liberal values.
It is our capacity for rational choice that differentiates
humans from other creatures. Respect for this capacity -
especially our right to be the informed gatekeepers of our
own bodies - is an indication of the seriousness with
which we respect the humanity and dignity of others.
What is informed consent?
For patients to give their informed consent to surgery - to
be able to make a considered choice about what is in their
personal interests — they must receive sufficient accurate
information about their illness, the proposed treatment
and its prognosis. For this to be more than a moral
abstraction, you must complete four general tasks:
155
14
PREPARATIONS FOR SURGERY
1. Describe the procedure itself, including information
about its practical implications and probable prognosis.
2. Reveal the probability of specific associated risks or
complications.
3. Do not assume that the patient already knows the
risks of other aspects of the proposed surgical
procedure, such as the complications that might
result from a general anaesthetic, bed rest,
intravenous fluids or a catheter.
4. Outline other surgical or medical alternatives to the
proposed treatment, including non-treatment, along
with their general advantages and disadvantages.
Ideally, the amount of such information should be that
which a mentally competent patient requires to make
informed choice a realistic possibility Think of compe-
tence here as the ability to understand, retain and delib-
erate about such information and to accept its personal
applicability You must remember that the amount of
information the patient is obligated to divulge may well
change, depending on what you should know about your
patient as an individual. For example, it may not be
necessary for a manual labourer to be told of an extremely
small operative risk of minor stiffness in one finger. This
would obviously not be true of a concert pianist, under-
lining the importance of recording the patient's employ-
ment in case notes and referring to it in the presentation
of case histories.
both. However, it is clear that you are morally respon-
sible for attempting both to an acceptable standard. To
achieve this, ask the patient to repeat in personal terms
what has been said, and at various times invite questions.
The more confident you are in exercising these skills, the
less time is needed to obtain effective consent.
4. We often limit the amount of information we give to
patients on the grounds that it is potentially distressing.
If your long-term aim is to keep the patient in ignorance,
this is not acceptable. All competent individuals have a
right to decide what is and is not in their best interests,
even if what they decide is not endorsed by their profes-
sional advisors. It would not be morally acceptable for a
solicitor or accountant to delude their clients on the
grounds that they did not want to distress them about the
possibility of losing a court action or of going bankrupt.
Why should your moral obligations be any different?
Key points
• It is your responsibility to provide clear
information, and to determine whether it has
been understood.
* It is the patient's right to decide what is in his
or her best interest, not yours.
Good consenting practice
1. As much as possible, ensure that the physical sur-
roundings during the discussion between you and your
patient are conducive to easy quiet conversation. Ideally
choose somewhere private and free of disturbances and
interruptions by junior staff or medical students follow-
ing in retinue on a busy Nightingale ward. Do not stand
threateningly over the patient in bed, and avoid giving
the appearance of being rushed by other duties. Empathy
with the patient is crucial.
2. Use the simplest possible language, avoiding needless
technicalities. If the patient permits it, have a relative or
friend of the patient present when serious matters are being
discussed. This is both for support and to help ensure that
the patient really does understand - both at the time the
information is given and later when the patient returns
home. In the hospital ward, nurses familiar to the patient
can often fulfil this role effectively Appropriate leaflets or
booklets can be helpful, as is innovative work using
audiorecording of interviews; patients can be encouraged
to take the recording home to discuss with others.
3. Having attempted to provide clear information, now
determine whether or not the patient has actually under-
stood it. No doubt there are time constraints on doing
The consent form
1. In principle, the consent form signed by the patient
before operation is a public and permanent affirmation of
agreement. All competent patients who are 16 years or
older should sign the form for all surgical procedures
involving a general anaesthetic. You should obtain
signed consent for procedures under local anaesthetic if
there is a risk of significant sequelae; for example, an
excision of skin lesions. You should also sign the form
after obtaining consent to indicate that, to the best of your
knowledge, the patient has both received and under-
stands the information necessary to make a considered
judgement.
2. However, it is unnecessary for a competent patient to
sign for all surgical interventions. A simple investigative
procedure such as venepuncture, involving minimal risk,
can be undertaken after oral explanation of, and consent
to, what it physically entails. Consent can be assumed to
be implied if the patient then accepts the procedure.
3. The consent form is not legal proof that consent has
been given. Always bear this in mind if you are tempted
to cut corners as regards good practice in obtaining
consent. It is merely one piece of evidence that some
attempt was made to obtain informed consent, not that it
was a morally or legally satisfactory attempt.
156
CONSENT FOR SURGICAL TREATMENT
14
THE LEGAL IMPORTANCE OF
INFORMED CONSENT
Key point
In addition to the general and clinical
importance, your legal obligation is to respect
the patient's right to consent to treatment.
Battery
1. Battery is a violation of the civil law forbidding
intentionally touching other persons without their
consent. For example, a woman won damages in the UK
for this reason because she was given a hysterectomy to
which she did not agree in the aftermath of a gynaeco-
logical operation for another problem. In Canada, a
woman who made it clear that she wanted to be injected
in one arm successfully sued when she received the injec-
tion in the other! The harm resulting from battery is not
necessarily physical. In law, a battery can be deemed to
have occurred without such harm having taken place.
Here, harm should be construed as the violation of the
right of persons to exercise autonomous control over their
own bodies,
2. In many situations involving minor surgical proce-
dures or tests, it is not possible or advisable specifically to
ask for consent every time you touch a patient. If this
were the case, surgery would become impossible. But it
does not follow that the patient's consent is legally irrel-
evant. Rather, as we have just seen, a patient can be said
to have given implied consent by virtue of presenting for
treatment and accepting what is offered. A man once
argued in the USA, for example, that a ship's surgeon had
committed a battery because he was vaccinated without
having given specific verbal permission for the injection
to be administered. He lost on the grounds that his
consent was implied because he was in a queue of people
who were clearly waiting to be injected and he held out
his arm when his turn came!
3. Clearly, there will be many less clear-cut situations.
Is there a risk of battery if a patient claims that surgery
would have been refused if more information had been
given beforehand? If you informed the patient in broad
terms of the general nature of the condition and the
proposed operation to try to correct it, if you did not
deliberately deceive and the patient gave no indication of
desiring not to proceed by asking for more information,
and signed the appropriate consent form, then the
answer is probably no. This presupposes that you
have not deprived the patient of information that was
specifically requested, and, returning to our example of
an unwanted hysterectomy, you have not usurped a
clinical choice legally regarded as remaining with the
patient.
Negligence
1. Battery is not the only legal action you risk for in-
adequately respecting your patient's right to informed
consent. In an important case, Mrs Sidaway suffered
paralysis resulting from spinal surgery to relieve pressure
on a nerve root without being told that the operation
carried a small risk of paralysis. Here, it was judged that
she had not been a victim of battery because, again, she
had given her general consent to the surgery in question.
However, her solicitors then claimed negligence, the legal
action now recommended in such cases. Negligence a
potential breach of duty, concerns your professional duty
properly to advise patients not just about the proposed
surgery but also about its potential hazards. In such
cases, patients argue that, had they known the risks in
question, they would not have proceeded with the
surgery.
2. Do not assume that in these circumstances you are
protected from such accusations by a signed consent form
for treatment. The patient might still successfully argue
that, even having signed the form, he or she was not given
enough relevant information to make an informed deci-
sion before signing and /or was unaware of the signifi-
cance of the form. There is no escaping your general duty
to disclose information about potentially harmful side-
effects and to do so in a way that the patient can under-
stand in principle. For example, in all cases other than
those of acute emergencies, you must take care to provide
translations for non-English-speaking patients.
3. How can we establish whether or not compliance
with this duty has been sufficient - whether or not
enough information has been disclosed about risks so that
the rights of patients are respected? Legal judgements
concerning negligent standards of adequate disclosure in
the UK are still primarily determined by the profession
itself. Suppose that expert witnesses for the defence are
regarded by the court as constituting a recognized body
of professional opinion. If they agree that they would
have communicated the same amount of information in
similar circumstances as the defendant, this should be
sufficient to ensure that the claimant will lose the legal
action. In other words, in such actions the judge does not
decide which expert witnesses are right - those for the
claimant or defendant. All that is required to exonerate
the latter is for a responsible body of professional opinion
to endorse the action in dispute, even if the endorsement
does not represent the views of the majority of members
of the profession.
157
14
PREPARATIONS FOR SURGERY
4. Recent legal developments have underlined this
'professional standard' in the determination of what
constitutes negligent informed consent. In the Sidaway
case, for example, a majority of the judges in an appeal
to the House of Lords agreed with this approach to
determining negligence, as have other judges since.
However, many have also warned of the dangers of com-
pletely equating the right of patients to information with
standards set by the profession. Indeed, in the Sidaway
case, one judge stated in a minority opinion that there will
be some information about surgery, for example serious
hazards, which any 'prudent' patient would wish to
know before giving consent to proceed. A similar legal
standard of negligence as regards informed consent is
found in North America and has largely become
accepted good practice by the medical profession in the
UK.
5. Therefore, do not look to the law for advice on how
much information about risks and side-effects is morally
required by the right of your patients to informed
consent. Ask instead what a reasonable person would
want to know under similar circumstances, especially in
the context of any other personal information you have
about the patient and his/her public and private
interests. Disclose the same amount of information
about risks to your patients as you would wish to be
communicated to your close friends and relatives. The
fact that an adequate amount of information for
informed consent may be legally acceptable does not
entail that this should be regarded as professionally or
morally acceptable.
The unconscious adult patient
1. Suppose that you are a surgeon in the accident and
emergency (A & E) department, confronted with the
victim of an automobile accident who requires an imme-
diate operation to save life or to prevent permanent and
serious disability Here, there is a clear duty to treat,
despite the fact that it is impossible to obtain the patient's
consent, and there would be no risk of battery if oper-
ation proceeded. This is not because you become the
proxy of the patient and so make a substituted judge-
ment on his or her behalf, one which attempts to antici-
pate the choice the patient would make. It is because it is
your moral and legal responsibility to act in the patient's
best interests - to do what is 'necessary', as there is no
way of knowing for certain what the patient might
choose.
2. Indeed, no adult in the UK can legally consent to
surgery on behalf of another, including close relatives. Do
not ask relatives to sign consent forms on behalf of uncon-
scious or otherwise incompetent adults. It would be both
a misrepresentation of the law and a liability risk, if the
surgical outcome is poor. The relatives may inappropri-
ately and harmfully blame themselves.
3. The only circumstance that justifies surgery without
consent is the dramatic need of patients, coupled with
their inability to give consent. Inconvenience will not
suffice. For example, the arrest of a life- threatening haem-
orrhage in an otherwise healthy patient would clearly be
in order, while the same could not be said of the repair of
a hernia. Of course, if the patient is conscious and evi-
dently capable of rational judgement, then even in an
emergency offer advice on the condition and the pro-
posed treatment. If it is physically possible, have the
patient also sign a consent form, as would be the case in
normal circumstances. Verbal consent is adequate if the
patient's condition precludes giving written consent.
However, in these circumstances, if possible, ask another
health worker to act as a witness and to record the verbal
consent in the notes.
Children
1. Ordinarily, obtain consent for elective surgery on
young children from someone - usually the parent -
deemed competent to make informed choices about the
child's best interests. However, this does not suggest that
you must always be guided solely by parental wishes. If
you believe such a decision is necessary to save the child's
life, the parents' wishes can be overridden. If there is time,
apply to the court for the appropriate order. If not, you
can still proceed. If the parents propose long-term treat-
ment or non-treatment options which you regard as simi-
larly inconsistent with the best interests of the child,
again you can apply for them to be overriden by an
appropriate court order.
2. The legal age for medical consent is normally 16.
However, it is legally acceptable for you to treat adoles-
cents under the age of 16 years without parental consent,
just as it is for general practitioners to prescribe contra-
ceptives. If you intend to do this you must ensure that the
young person is competent - mature enough to under-
stand, retain and deliberate about information concerning
the nature of the illness, the prognosis, proposed treat-
ment and any important associated risks. The patient
must also be able to believe that this information applies
personally to her or him. Before proceeding without
parental consent, encourage the young person to discuss
the proposed treatment with the parents and so be
assured that the treatment is in the best interests of the
child.
3. Nevertheless, regard treatment without parental
consent as exceptional. Unless the adolescent has specifi-
cally refused permission, attempt if possible to hnd and
158
CONSENT FOR SURGICAL TREATMENT
14
consult the parents if they are not already approachable.
In the case of life-threatening illness / even young people
below the age of 18 years do not have the right to reject
treatment on their own which might save their lives. Only
those with parental responsibility can exercise such
judgement, in agreement with you. Paradoxically, the law
appears to be that the right of a competent adolescent to
consent to life-saving treatment does not entail the right
to refuse it. As regards elective surgery which is not life
saving or will not prevent serious and permanent injury
the law is the same. Morally, however, the wishes of the
competent young person not to proceed should be and
are commonly respected, even where the parent dis-
agrees. If surgical treatment is forced upon such patients
without consent, it might undermine the relationship of
trust and the willingness to comply with future treatment,
both of which will be important for sustained clinical
success. Such force can be argued not to be in the best
clinical interests of the child.
4. Quite young children often have a good grasp of
their prospects and treatment, especially when they have
already experienced distressing surgical therapy for
an illness which they have had for some time. In such
circumstances, before further surgery is undertaken,
attempt to consult such a child about his or her wishes.
Where there is disagreement between parent and child
about the best course of action, especially in instances of
potentially terminal disease, arrange counselling for both
about what appears clinically to be in the child's best
interests. Such counselling is particularly important when
there is disagreement between you and the parent about
the most appropriate way to proceed. Again, in the un-
usual event that you believe parental choice dramatic-
ally conflicts with the medical interests of the child,
approach the court for a judgement.
Mental handicap and psychiatric illness
1 . In the case of adults who are judged incompetent to
choose for themselves, we have seen that no one may
legally act as a proxy for this purpose. However, decisions
about incompetence are complex. For example, incompe-
tence to consent to surgery does not follow from severe
psychiatric illness. Just because individuals may be
incompetent in one respect due to illness does not mean
that they are incompetent in all respects. People may be
detained under the 1983 Mental Health Act on the
grounds that, because of the seriousness of their psychi-
atric illness, they are a potential danger to themselves or
others. As a result they may be given psychiatric treat-
ment without their consent. However, this does not hold
for ordinary surgical treatment. In such circumstances,
attempt to obtain the patient's consent, even when com-
munication is difficult and certainty of understanding not
assured. For example, in a recent legal case in Britain, a
judge accepted that a detained patient suffering from
schizophrenia was competent to refuse to have a foot
amputated if it became terminally gangrenous.
2. With the exception of specific and extreme interven-
tions such as psychosurgery, there are circumstances
when surgical treatment can be given to a detained psy-
chiatric patient who cannot consent due to extreme
illness. There are two conditions:
a. the treatment must be deemed necessary to protect
life or to avoid permanent and serious disability
b. the patient must be diagnosed as unable to give
informed consent as a direct result of the psychiatric
illness.
As a consequence of psychotic delusion, for example,
patients may believe that you are going to kill them and
that the diagnosis of a life-threatening condition is a
sinister plot. Here, necessary treatment can proceed, pro-
vided that you and the relevant psychiatric team agree
that it is in the best interests of the patient. Note that this
exception to the consent requirement would not ordi-
narily apply to elective surgical care, as the assumption
should be that there will be time for patients to make up
their own minds when their competence to do so is no
longer being impaired by their illness.
3. Some patients in need of surgery suffer not from
psychiatric illness but from permanent mental disability.
This may severely impair competence to give informed
consent for either life-saving or elective surgery. The fact
remains, however, that in such circumstances no adult
can act as a legal proxy for another as regards the pro-
vision of such consent. The only person who can make
the decision that surgery is in the best interests of
severely mentally handicapped patients is yourself in
consultation with the principal carers, including close
relatives. Take great care. As regards elective surgery,
responsibility for promoting the interests of mentally
handicapped patients can be a heavy burden, especially
if there is dispute among carers about what these actu-
ally are. The sensitivity of these issues is witnessed by
the fact that the courts sometimes refuse to permit the
sterilization of mentally handicapped women under the
age of 16 years, even if the surgeon has agreed to
perform the procedure.
TWO PRACTICAL PROBLEMS
^AW^S-ifesMiWiK;*©;
The general obligation to disclose information about both
proposed surgery and its hazards is not open to debate.
However, putting this moral and legal imperative into
practice does involve discretion and is not always easy,
for two reasons.
159
14 "
PREPARATIONS FOR SURGERY
Limitations on the understanding of patients
1 . It is sometimes unclear whether or not consent has
really been obtained, even if you have taken care to
explain the proposed procedure and its potential hazards.
The comprehension of competent patients can be com-
promised by their illness, their educational and social
background and by other aspects of their personalities
which may make them overly anxious or unwilling to
listen. Difficult as such instances of impaired autonomy
can be, especially for patients facing acute and complex
surgery, you must still be able to show that they have
disclosed adequate information for proper consent to be
possible.
2. Practically speaking, therefore, how should you
demonstrate to yourself, and if necessary to a judge, that
you have done your best in this regard? Most important
of all, you need to work constantly to improve your
ability to communicate. Both the General Medical Council
(GMC) and the British Medical Association (BMA) stress
this point, and its importance is underlined by the
increasing emphasis placed on communication skills
within medical education (see Ch. 47). You can do no
more than your best.
3. Keep a written record in the case notes of the main
points about treatment which have been communicated
prior to the signing of the consent form. Follow the model
of the reasonable patient outlined above. Give informa-
tion on what will be done and why, along with significant
risks of mortality and other hazards to bodily functions
relevant to normal social participation, such as swallow-
ing, speaking, continence, mobility, pain and sexual per-
formance. Record that each of these variables has been
mentioned and will provide evidence that may be useful
if the fact is denied by the patient in a context of a medico-
legal dispute.
Limitations on the right of patients to
consent
e
Key point
• Consider reinforcing information about
proposed treatment and possible side-effects
with written information.
4. Even after you have followed good practice in
obtaining consent, you may conclude that your patient
still cannot be said to have given proper consent to treat-
ment. Apart from life-saving emergencies, your most
appropriate choice is to postpone treatment until you
have achieved better communication. This may be incon-
venient, but it is necessary to protect the patient's rights
and to demonstrate that you have taken your moral and
legal duties seriously.
Key points
• The right of a patient to consent to surgery
does not entail (imply as an inevitable
consequence) a right to demand and receive it.
• You do not have a professional duty to provide
requested surgery for a patient who has no
need for it.
• You may also refuse to carry out an operation
that will be futile, no matter how much the
patient may want it.
1 . What happens if the patient clearly needs operation
but does not want it? Here, respect for the autonomy of
patients may well conflict with your other moral obliga-
tion to protect life and health. This conflict is most acute
when, in considered and unambiguous terms, a patient
refuses life-saving surgery. The moral and legal emphasis
on respect for autonomy within surgery is so strong that,
even in such circumstances, you must not undertake
treatment without consent, again assuming that the
patient is conscious and competent. This fact is sometimes
obscured because patients who are terminally ill and do
not wish further treatment are reticent about refusing it.
It becomes very clear, however, in the case of a Jehovah's
Witness, who will only proceed with surgery on the
understanding that no transfusion will be given in the
event of haemorrhage. Legally, a competent patient has
every right to make such a demand. If you ignore this you
risk an action for battery.
2. It is not suggested that you have to operate on
patients who place stipulations on the types of life-saving
treatment they will accept. In principle, and assuming
that there is time, you may refer them to others who are
more sympathetic and willing to undergo the stress that
such restrictions inevitably carry. Equally, we have
already seen that, if a patient is unconscious or incompe-
tent for some other reason you must do what is necessary
to try to save life. However, even this is changing in the
face of so-called 'advance directives' or living wills',
which are now regarded by expert opinion in the UK as
having legal force. Thus any competent adult can draft a
document specifying in advance which life-saving treat-
ments are and are not acceptable if the patient becomes
incompetent and contracts specific types of illnesses.
Ideally, an advance directive should be witnessed and
you should act upon it. Such documents are common in
North America and will eventually be so in the UK.
3. After consultation with you, a competent patient
may, therefore, decide that further treatment is pointless,
160
CONSENT FOR SURGICAL TREATMENT
14
given the irreversible and terminal character of the par-
ticular disease. If you comply with such a request to omit
or to stop treatment, it can be argued to be neither actively
killing nor aiding and abetting suicide. It is reasoned that,
unlike the potential suicide, competent patients may well
want desperately to live, but not at any cost to their
quality of life. Furthermore, as we have seen, to treat them
against their will constitutes a battery. Whatever the cor-
rectness of these arguments, what patients cannot expect
is for active steps to be taken to end their lives, although
they do at times request this as well.
4. Yet to go along with a patient's refusal of surgery
when it is clear that the consequence will be death is a
very serious moral and legal matter. Take great care to
ensure that the patient fully understands the implications
of refusing life-saving treatment and is competent to make
an informed judgement, especially if the refusal is
followed by a lapse into unconsciousness. A mistake,
either about the patient's understanding or wishes, cannot
be corrected. Therefore, respect prior refusal only if you
judge it to be an autonomous decision intended to apply
in the circumstances that have arisen. For example, a
young adult woman in the UK refused a blood transfusion
on the grounds of her acceptance of the doctrine of the
Jehovah's Witnesses, despite the fact that she was not a
Witness herself. She lost consciousness and the court over-
ruled her refusal on the grounds that she had been unduly
influenced by her mother and that her decision was based
upon inadequate information about her prognosis.
INFORMED CONSENT AND SURGICAL
RESEARCH
S^MS^ffi^S^iSS
ymtfSMviteWtfmm
1 . The availability of surgical options is dependent on
the experimental research which makes them possible. Yet
researchers must be careful. Without enthusiasm and con-
viction about the importance of their work, they will not
have the commitment that successful research requires.
However, such commitment can lead to an underestima-
tion of the risks or discomfort of experiments. Research
can be either therapeutic and to the potential benefit of
participants, or non-therapeutic with no such promise.
Participants in the former will be patients, and in the latter
either patients or healthy volunteers.
2. Patients involved in research have a right to
informed consent for the same reasons described above.
By allowing them to make an informed evaluation for
themselves, they exert a regulating influence on experi-
mental zeal; this has unquestionably led to moral abuses
in the past. A clear example is the notorious and need-
less experiments inflicted by some Nazi doctors and sur-
geons on Jewish prisoners. However, there have been
more recent illustrations involving patients, some of
whom have died as a result of their participation in
research.
3. The Nuremburg Code was adopted internationally
as a result. It declared that 'the voluntary consent of a
patient is essential' in any medical research. The later
Declaration of Helsinki is also explicit. It states: Tn any
research, each potential subject must be adequately
informed of the aims, methods and anticipated benefits
and potential hazards of the study and the discomfort it
may entail/ After this, participants' consent must be
obtained.
4. The enforcement of the Helsinki Declaration in the
UK is entrusted to research ethics committees. These are
administered by health authorities and are responsible for
evaluating all surgical research involving humans, wher-
ever it might be undertaken. Under no circumstances
should research proceed without the approval of the
appropriate ethics committee, and academic journals
usually publish the results only when such approval has
been given. In principle, research ethics committees are
supposed to ensure that the proposed protocol makes
good scientific sense and poses no further risks than those
of the best available treatment. Only then should patients
be asked to consent to participate, on the basis of being
given appropriate information about the research that the
committee has also approved.
5. There is, however, one remaining, significant
problem concerning surgical research and informed
consent. As a result of differing ability and willingness to
understand and to question medical authority, we have
seen that patients vary in their ability to assimilate the
details of clinical information. Consequently, enthusiastic
researchers are in a position, wittingly or not, to manipu-
late patients to subject themselves to procedures that
might not be proposed in ordinary treatment. Patients
may be encouraged to agree to participate in the devel-
opment of surgical procedures, for example, without
realizing how experimental they are. Here, the general
guidelines concerning informed consent must be fol-
lowed with extra vigilance. For example, take care to
identify surgical procedures that might not be regarded as
standard professional practice and proceed only when the
patient gives informed and written consent with the
knowledge that this is the case. When in doubt about
whether or not a procedure is standard, consult the
research ethics committee. You must not pretend that a
surgical innovation that goes beyond a minor incremen-
tal variation on already standard procedures is not
research that requires further ethical evaluation before
proceeding.
6. In non-therapeutic research with patients or healthy
volunteers, you must be equally stringent to avoid con-
fusing agreement to participate with informed consent to
do so. Try to ensure that the moral legitimacy of the
161
14
PREPARATIONS FOR SURGERY
consent of the volunteer is not obtained under financial,
social or professional duress. In the UK, for example, the
difficulty of doing so has led to surgical research not ordi-
narily taking place among the prison population.
INFORMED CONSENT AND
CONFIDENTIALITY
*^?&j£-W£>&''^
1. As a corollary of their right to informed consent,
patients have the right to control access to information
which they give to you for the purposes of treatment. The
General Medical Council (GMC) supports this right
through the importance it attaches to the principle of con-
fidentiality - obtaining the permission of patients before
revealing clinical information about them to others. Few
acts can more quickly lead to you being professionally
disciplined than a proven breach of confidence in unwar-
ranted circumstances.
2. There are two types of justification for this empha-
sis. First, the right to be the moral gatekeeper of one's own
body extends to information divulged in clinical consul-
tations. Second, if patients are frightened that their con-
fidence might be breached, they may not be willing to
provide the honest information on which successful
diagnosis depends, or even to turn up for treatment at all.
This can pose a severe danger to them and possibly to the
general public.
3. It is in the area of potential conflict between the
freedom of the individual and the interest of the public
that circumstances may arise in which you either must or
might divulge information otherwise regarded as private.
The same professional codes which stress the importance
of confidentiality (the 'Duties of a Doctor' of the GMC, for
example) also outline the exceptions to the rule. These fall
into two general categories.
The public interest
1. Suppose that in a clinical consultation in the acci-
dent and emergency department you discover that a
highly agitated patient is armed, has committed a
robbery and has killed a bank clerk and a customer as a
result. Here, it seems straightforward that the confidence
should be broken and the police informed- The patient
may strike again. Indeed, it is legally mandatory to
breach confidentiality where patients are suspected of
involvement in terrorism within the UK or where they are
found to be suffering from a highly infectious and notifi-
able disease.
2. How serious must a risk to the public actually be to
breach confidentiality legitimately? For example, are you
just as willing to report someone who confesses in confi-
dence to stealing a badly needed winter coat? It is not
always easy to balance the interests of the patient against
those of the public. This can create difficult dilemmas for
you when the two seem in direct conflict and when, as is
often the case, there is considerable professional discre-
tion as to how morally to proceed. Debates about HIV and
AIDS have recently underlined these issues.
3. Two things are clear.
a. First, it does not follow from a claim that the public
interest demands a breach of confidence that it actually
does. For example, the police have no right to disclosure
or to access clinical records that may provide evidence of
a crime. A judge may issue a warrant legally authorizing
such access or a subpoena demanding disclosure in court.
However, even this does not make it morally mandatory.
Some clinicians have felt so strongly about the immoral-
ity of breaking a patient's confidence that they have
risked being charged with contempt of court for refusing
to do so. Do not fuse the law and morality, even though
they often do overlap.
b. Second, patients have no right to harm others
through the exercise of their right to confidentiality. There
is an obvious link between this right and the right of indi-
viduals to control the use of their private property. Yet just
as the legitimate exercise of this property right stops at the
point at which the safety of others is threatened, the same
can be said about clinical information. Therefore, if you
discover that maintaining confidentiality will lead to the
threat of serious harm to another known individual - the
suspicion of a general threat is not sufficient - then a
breach of confidence may be warranted. For example,
although the legal precedent does not apply in the UK, a
psychiatrist in the USA was successfully sued for negli-
gence for not informing a young woman that he had
clearly been told by a patient that he was going to kill her.
He did. If you do consider a breach of confidence to a
third party in these circumstances, it is always important
to warn the patient that this is what you intend.
The interest of the individual patient
1. Breaches of confidence may not just be in the public
interest. They may also be necessary in order to obtain
information vital for successful treatment. Because of the
physical or psychological effects of their illness, some
patients are unable to communicate clearly about their
medical history. Under such circumstances, you may need
to consult relatives or friends, especially in emergencies.
2. This said, still make strong attempts to obtain the
patient's consent and to verify the identity of any others
from whom information is sought. Reveal no more infor-
mation about the patient's condition than is necessary for
the clinical purposes at hand. Keep knowledge confiden-
tial concerning prognosis and treatment, for example.
Remember how its unwarranted spread might drastically
162
CONSENT FOR SURGICAL TREATMENT
affect the patient's private and public life. Never com-
municate clinical information over the phone to those not
involved in treatment, unless it is with the patient's prior
consent and there is a reliable way of identifying the
person to whom you give the information.
3. The interests of patients are also served if you share
clinical information they have given you, with colleagues
whose assistance you require. Patients are presumed to
consent to such revelations by virtue of their general
agreement to treatment. Given the complexity of its divi-
sion of labour, surgery is an essentially cooperative exer-
cise and its success depends on the free flow of relevant
information. This said, allow access to information only to
those professionals involved - something which requires
caution, especially on open wards.
surgical team accept that the final decision about how to
proceed is reached after an open and reasoned discus-
sion. Everyone then has the chance to present their
arguments. As a result, clinicians are more willing to
cooperate in the search for a common view, even though
it involves a degree of what may be perceived as moral
compromise. Open communication does not have to con-
flict with the recognition that it is the senior clinician
who takes responsibility for the final choice. If you are a
surgeon in authority, always try to create space for such
discussions, a practice that is increasingly common in the
face of taxing moral dilemmas that have to be resolved
in short periods of time - for example, those concerning
the withdrawal of life sustaining treatment.
MORAL INDETERMINACY, INFORMED
CONSENT AND OPEN
COMMUM
1. Thus far, we have examined the general principles
governing informed consent that are endorsed by the sur-
gical profession and which are reinforced by statute and
case law. Yet, clear as these are, their correct interpreta-
tion may be much more obscure in practice. Such rules do
not interpret themselves: you must interpret them as an
individual when faced with the complexities of specific
cases.
2. In the majority of cases there is a consensus among
the surgical team about the most appropriate interpreta-
tion. It will be reasonably clear, for example, how much
information should be communicated to knowledgeable
patients about the hazards of a particular treatment and
whether or not they have understood enough of it to
warrant proceeding. Yet in some situations, such agree-
ment does not exist and interpretations are conflicting.
Reference to the facts of the case themselves cannot solve
the problem. Their openness to conflicting interpretation
is what poses it.
3. Suppose, for example, that despite careful attempts
to communicate the considerable risks of an urgently
needed operative procedure there is still disagreement
within the surgical team about whether or not the patient
has fully understood. Against the background of the
necessity to come to a quick decision, there may be no
'right' interpretation as to how to proceed ethically.
4. Another illustration might be conflicting beliefs
about whether or not to operate urgently on a Jehovah's
Witness who refuses a blood transfusion but seems
to be doing so partially under pressure from family or
congregation.
5. What is crucial in such circumstances is that,
despite their disagreements, individual members of the
Summary
• Do you respect the right of patients to
give or withhold consent to surgical
treatment?
• Will you provide patients with sufficient
information to make informed choice
possible?
• Even in surgical emergencies, will you
avoid overriding the right of conscious and
capable patients to decide on treatment?
• Will you continue to respect the rights of
all patients, including children, and those
who are unconscious, mentally
handicapped or psychiatrical ly ill?
ACKNOWLEDGEMENTS
Many thanks to John Cochrane, Robert Cohen, Lesley
Doyal, John Dickenson, Arlene Klotzko, Alastair
McDonald, Rosanne Lord, Paul Lear, Norman Williams,
Daniel Wilsher, Christopher Wood and Richard Wood.
Special thanks to Ian Kennedy.
Alderson P 1993 Children's consent to surgery. Open University
Press, Buckingham
Beauchamp T, Childress J 1994 Principles of biomedical ethics.
Oxford University Press, New York
Brazier M 1992 Medicine, patients and the law. Penguin,
Harmondsworth
British Medical Association 2001 Withholding and withdrawing
life-prolonging medical treatment. BMJ Books, London
163
14 *
PREPARATIONS FOR SURGERY
British Medical Association 2001 Consent, rights and choices in
health care for children and young people. BMJ Books, London
Buchanan A, Brock D 1989 Deciding for others: the ethics of
surrogate decision making. Cambridge University Press /
Cambridge
Doyal L, Tobias J (eds) 2000 Informed consent in medical
research- BMJ Books, London
Harris J 1985 The value of life. Routledge, London
Kennedy I, Grubb A 2000 Medical law. Butterworths, London
Lipkin M, Putnam S, Lazare A (eds) 1995 The medical interview:
clinical care, education and research. Springer, New York
McHale J, Fox M 1997 Health care law - text and materials.
Sweet and Maxwell,, London
McLean S 1989 A patient's right to know: information
disclosure, the doctor and the law. Dartmouth,
Aldershot
Mason J, McCall Smith R 1999 Law and medical ethics.
Butterworths, London
Montgomery J 2002 Healthcare law. Oxford University Press,
Oxford
Rothman DJ 1991 Strangers at the bedside: a history of how law
and bioethics transformed medical decision making. Basic
Books, New York
Royal College of Surgeons 1997 The surgeon's duty of care.
Royal College of Surgeons, London
Wear S 1993 Informed consent. Kluwer, Dordrecht
164
Preoperative preparation for
surgery
S. Bhattacharya, G. M. H. Wray
Objectives
• Understand the general principles of
preoperative preparation.
• Appreciate how, in high risk patients,
preoperative preparation may lower the
risk.
• Understand the principles of preparation
for specific types of operation.
• Appreciate the value of protocols and
routines, and the importance of adhering
to them, even in emergency situations.
To obtain satisfactory results in surgery, a careful pre-
operative preparation of the patient is vital. Attention to
detail is the key to success. The importance of this pre-
paration becomes more evident as the surgical procedure
performed becomes more complex.
ROUTINE PREOPERATIVE
PREPARATION
£&^&£&!^£&^*A&
Evaluation
1. Take a full history and exclude any significant
medical problems (see Ch. 6).
2. Check clinical signs against the planned surgical pro-
cedure, in particular noting the side involved. Confirm
that the planned operative procedure is appropriate.
Key point
During the interval between the decision to
operate and the actual operation, the disease
may have progressed, making the intended
operation inappropriate; seek advice from a
senior colleague.
3. Take a full drug history with specific enquiry regard-
ing allergic responses to drugs, latex and skin allergies.
Continue medication over the perioperative period, espe-
cially drugs for hypertension, ischaemic heart disease and
bronchodilators. Give patients on oral steroid therapy
intravenous hydrocortisone. Stop oral warfarin anticoag-
ulation 3^1 days preoperatively and check the prothom-
bin time prior to surgery. If the prothrombin time remains
unacceptably high, the patient may require an infusion of
fresh frozen plasma. Those on warfarin who have had a
life-threatening thrombotic episode (e.g. pulmonary
embolus) within the previous 3 months should be
switched to heparin intravenously until 6h before
surgery; the heparin can usually be recommenced 4 h after
surgery Patients taking aspirin or other antiplatelet medi-
cation (e.g. clopidogrel) may have an increased risk of
bleeding; stop these drugs for at least 48 h preoperatively
for major surgery. Stop drugs, over the perioperative
period, that may interfere with anaesthetic agents, includ-
ing monoamine oxidase inhibitors, lithium, tricyclic
antidepressants and phenothiazines. If possible, stop the
oral contraceptive pill 4 weeks prior to any major surgery.
Postmenopausal patients on hormone replacement
therapy do not need to have their medication stopped
before an operation.
4. There is a clear correlation between malnutrition in
the preoperative period and an increased morbidity and
mortality from surgery (see Ch. 10). Nutritional assess-
ment can be based on total body weight loss, anthropo-
morphic measurements such as skinfold thickness to
assess the amount of subcutaneous fat, or biochemical
tests that reflect protein deficiency, such as the measure-
ment of serum albumin, prealbumin or transferrin. Such
preoperative nutritional assessment may detect patients
in whom malnutrition is a major concern for their oper-
ative procedure, but the correction of this malnourished
state, which in part reflects their underlying disease
process, may be impossible in the preoperative period.
Highlight the problem to allow you to commence nutri-
tional support at an early stage and consider inserting a
feeding enterostomy or a designated central venous
feeding line at the time of operation. Do not consider
165
PREPARATIONS FOR SURGERY
correcting a low preoperative serum albumin level with
human albumin solution except as an adjuvant to full
parenteral or enteral nutrition. It is an ineffective and
expensive method of providing nutritional support.
5. Young and fit patients undergoing minor procedures
do not require any preoperative investigations {see Ch. 4).
In older patients or those with significant medical prob-
lems, standard investigation would include a full blood
count, urea and electrolytes, chest X-ray and electrocar-
diogram. For a critical evaluation of routine preoperative
investigations see Velanovich (1994).
Routine preoperative measures
1. Each clinical firm evolves a standard protocol for
preoperative preparation appropriate for its patients.
Adhere to the protocol followed by your firm. Use a
checklist - these are very useful to ensure that you do not
leave out an important step.
2. Prohibit solid diet to adult patients for 6 h, and clear
fluids for 4 h, prior to an elective general anaesthetic.
Fasting times for children vary in different hospitals and
they are also age dependent. A suggested regimen is
summarized in Table 15.1.
3. The operation site must be prepared by the removal
of hair, if this is necessary for access, using a depilatory
cream. Shaving or clipping hair from the operation site
increases the risk of infection, unless the skin preparation
is carried out immediately prior to surgery.
Table 15.1 Preoperative fasting times for children
i
Bab/es under 1 year
No breast milk for 2-3 h before anaesthesia
Mo formula feed for 6 h before anaesthesia
Clear fluids may be given up to 3 h before
anaesthesia
Children over 7 year
No food/milk for 6 h before anaesthesia
Clear fluids up to 3 h before anaesthesia
Key point
• Mark a unilateral operation site on the skin
with an indelible marker pen.
4. Explain to the patient (or guardian) the procedure
and any likely complications, answer questions the
patient may have, and only then have them sign the
consent form. If you are unable to answer the patient's
questions, seek help from a senior colleague. It is good
practice for the operating surgeon to obtain the patient's
consent; failing that, it may be done by another member
of the team who is familiar with the operation and its
aftercare. Consent should ideally be obtained from
patients not immediately before an operation but some
time ahead, so that they may have a period of reflection,
and an opportunity to ask further questions that may
arise.
5. Antibiotic administration is guided by the surgical
procedure involved and is discussed below, as is prophy-
laxis against deep vein thrombosis.
6. If specific services, such as frozen section histo-
pathology or intraoperative radiography are likely to
be required during the operation, organize these in
advance.
THHEJJSE^
1 . As a general rule, treat patients with clinical infec-
tion using systemic antibiotics before they undergo
operation.
2. Antibiotic prophylaxis for an elective operation
depends on the procedure being performed (Table 15.2).
3. Clean procedures, as for varicose veins, do not
require antibiotic prophylaxis. Abdominal operations not
associated with significant contamination, such as chole-
cystectomy, demand only a single dose of prophylactic
antibiotic given on induction of anaesthesia.
Table 15.2 The risk of infection
Type of wound
Clean
Cfean-contaminated
Contaminated
Description
Incidence of wound infection (%)
^
No violation of mucosa
2
No inflammation
No drains
Incision of mucosa but no spillage, or
10
Clean procedure in immunocompromised
Pre-existing infection
20-40
Spillage of viscus contents
166
PREOPERATIVE PREPARATION FOR SURGERY
15
4. Procedures in a contaminated field, such as appen-
dicitis, require a preoperative dose and two postoperative
doses. This regimen is also satisfactory for most other gas-
trointestinal tract procedures, including gastric surgery,
and colonic operations on prepared bowel.
5. The choice of antibiotic prophylaxis is determined
by the surgical procedure itself. Operations potentially
contaminated by skin flora require prophylaxis against
staphylococcal infection with flucloxacillin 500 mg intra-
venously. Procedures involving the bowel require broad-
spectrum cover for Gram-positive and Gram-negative
organisms and anaerobes. Commonly used regimens
include co-amoxiclav or a cephalosporin with metronida-
zole. Biliary tract procedures rarely involve anaerobic
contamination: a cephalosporin alone is satisfactory.
Table 153 Risk factors for deep vein thrombosis
Key point
If a patient has a penicillin allergy, avoid not
just penicillin but also drugs such as ampicillin
and amoxicillin. Cephalosporins have a 10%
chance of crossreactivity in patients with
penicillin allergy; prescribe them with caution.
PROPHYLAXIS AGAINST DEEP VEIN
THROMBOSIS AND PULMONARY
EMBOLI __
Pulmonary emboli are a major cause of mortality for sur-
gical patients, accounting for 10% of inpatient deaths in the
United Kingdom. Recent operation, immobilization and
trauma were responsible for 50% of deep vein thrombosis
(DVT) in a review by Cogo et al (1994), but there are other
important predisposing factors, such as the high oestrogen
content oral contraceptive pill, and significant obesity
(Table 15.3). Many risk factors cannot be avoided, but take
measures to avoid propagation of any thrombosis:
1. Subcutaneous heparin may reduce the incidence of
DVT by 50%; it is generally well tolerated but very occa-
sionally causes thrombocytopenia. Systemic anticoagula-
tion effects of low dose subcutaneous heparin are
minimal and haemostasis is not impaired. Newer low
molecular weight heparins (LMWHs), as effective as
standard heparin, need only once a day dosage.
Key point
Recent surgery
Immobilization
Trauma
Orat contraceptive pill
Obesity
Heart failure
Arteriopathy
Cancer
Age > 60 years
Adapted from Cogo et al (1994),
Epidural anaesthesia? Take precautions against
epidural haematoma.
Epidural (or spinal) anaesthesia significantly reduces
postoperative morbidity and mortality (Rodgers et al
2000) and is used for perioperative analgesia (see also
Chs 16, 35). Insertion and removal of epidural catheters
have been associated with the development of epidural
haematomas in anticoagulated patients with potentially
serious neurological consequences. Current recommen-
dations are to delay insertion or removal of an epidural
catheter for 12 h after a dose of LMWH. Delay subsequent
doses of LMWH for 2 h following catheter insertion or
removal (Wheatley & Veitch 1997).
2, Graduated compression stockings and intraoper-
ative intermittent pneumatic calf compression are also
effective in reducing deep venous thrombosis.
PREF^ATI^
For the management of specific preexisting comorbidity,
such as heart disease or diabetes, see Chapter 6. Risk
assessment is an important part of the preoperative
anaesthetic assessment. You may use the ASA (American
Society for Anesthesiologists) scoring system to assess
the overall risk (Table 15.4). The functional status of
patients with cardiac disease may be stratified using the
NYHA (New York Heart Association) classification
(Table 15.5). Risk stratification in patients in intensive
care may be done using more complex systems such as
the APACHE (Acute Physiology and Chronic Health
Evaluation) score (Knaus et al 1985).
Emergency surgery
1, The results of emergency surgery are less satisfac-
tory than those of elective procedures. The emergency
nature of the surgery may not allow sufficient time for
investigation and treatment of associated medical prob-
lems. Do not cut corners, and adhere to your elective pre-
operative protocols as far as possible. These patients are
commonly dehydrated and hypovolemic; if that is the
167
PREPARATIONS FOR SURGERY
Table 15.4
American Society for Anesthesiologists (ASA) status
Category
Description
Perioperative mortality (%)
I
II
III
IV
V
Healthy patient
Mild systemic disease - no functional limitations
Severe systemic disease - definite functional limitation
Severe systemic disease that is a constant threat to life
Moribund patient not expected to survive 24 h with or without
surgery
0.1
0.2
1.8
7.8
94
Table 15.5
New York Heart Association classification
Class
Description
IV
No functional limitation
Slight functional limitation. Fatigue, palpitations, dyspnoea or angina on ordinary physical activity but
asymptomatic at rest
Marked functional limitation. Symptoms on less than ordinary activity, but asymptomatic at rest
Inability to perform any physical activity, with or without symptoms at rest
case, their initial management must include insertion of
wide-bore venous access lines and prompt rehydration.
Consider inserting a central venous line, and also a
urinary catheter to assess the adequacy of rehydration.
Such patients may have sepsis, requiring systemic anti-
biotic treatment. Insert a nasogastric tube if there is insuffi-
cient time to allow for the usual period of fasting, or if you
suspect bowel obstruction.
Key point
• As far as possible adhere to your elective
preoperative routines.
2. Carefully judge the timing of the operation, and
involve senior colleagues in the decision making. The
morbidity and mortality audit (National Confidential
Enquiry into Perioperative Deaths, NCEPOD) performed
by the Royal College of Surgeons of England (Campling
et al 1993) suggests that the majority of patients with
acute surgical problems are better managed by active
resuscitation prior to operation performed on a scheduled
operating list by an experienced surgeon.
(ICU) preoperatively to undergo 'preoptimization'. The
value of this high standard of care has been recognized
for many years.
2. Survival following operation requires adequate
cardiac reserve. It is possible that the perioperative course
can be improved by setting targets for improving circu-
lating blood volume and cardiac function measured by
cardiac output, oxygen delivery and oxygen consump-
tion. The targets were originally defined by Shoemaker
et al in 1988, and are known as 'Shoemaker's goals':
• Cardiac index (CI) > 4.2 ml min" 1 m" 2
• Oxygen delivery (Do 2 ) > 600 ml min" 1 m~ 2
• Oxygen consumption (Vo 2 ) > 170 ml min" 1 m~ 2
They were chosen as representing 'survivor values' when
high risk surgical patients were studied retrospectively
and are claimed to improve survival if achieved preoper-
atively (Wilson et al 1999, Takala et al 2000). This involves
the insertion of a central line or pulmonary artery catheter
sufficiently early before operation to allow manipulation
of haemodynamics using fluid resuscitation, with or
without the addition of an inotrope such as dopexamine.
Beware of the risks of using high levels of inotropic drugs
to achieve Shoemaker's goals in those who fail to respond
to treatment or are in the late stages of septic shock.
Very high risk patients
1. Some patients are at particularly high risk because
they have significant comorbidity and may require a
major or emergency operation. If possible, admit them to
a high dependency unit (HDU) or intensive care unit
PREPARATION FOR SURGERY OF
SPECIFIC PATIENT GROUPS
r^^^y^<;i^-^^^^^t^::^i^
*ft&^?&% :: &^^
Preparation must be tailored to the procedures to be
performed and the stage of the underlying pathology
168
PREOPERATIVE PREPARATION FOR SURGERY
15
Large bowel operations
1. Most surgeons consider bowel preparation essential
to reduce the risk of sepsis, although some recent con-
trolled studies failed to prove any benefit from it. For elec-
tive operations, institute a liquid diet for several days
and administer oral purgatives on the preoperative day.
Sodium picosulphate (Picolax) 10 mg morning and night,
or polyethylene glycol /sodium salts (Klean-Prep) four
sachets in 4 litres of water taken 250 ml every 15 min, are
suitable. If they fail to cleanse the bowel, combine them
with mechanical washouts via a rectal tube. Elderly
patients may require intravenous hydration while under-
going bowel purgation to compensate for associated fluid
loss. Bowel preparation is usually contraindicated in
obstructed patients, although some surgeons advocate
on-table colonic lavage with the infusion of fluid through
a caecostomy or append icostomy; the effluent drains
through a wide-bore tube inserted proximal to the
obstruction.
Key point
• Warn all patients undergoing bowel surgery of
the possible need to create a colostomy or
ileostomy.
2. Before operation ask the stoma care nurse to select
and mark the most practical site for a colostomy on the
abdominal wall.
3. Counsel patients undergoing rectal surgery about
the risks of pelvic nerve injury with consequent impo-
tence and loss of bladder control.
4. Inform patients with Crohn's disease of the poss-
ibility of recurrence and anastomotic breakdown.
Similarly, discuss with patients undergoing pouch
surgery the likelihood of bowel frequency and inconti-
nence. Those undergoing anal surgery, especially for high
fistula, need to know about the risks of incontinence.
Upper gastrointestinal surgery
1 . Patients may be anorexic, in a poor nutritional state,
requiring correction by enteral or parenteral feeding
before and after operation. If the patient is vomiting,
detect and correct dehydration, electrolyte depletion and
possible acid-base imbalance. If there is evidence of
gastric delay or obstruction, insert a nasogastric tube to
empty the stomach and prevent aspiration at the time of
induction of anaesthesia. Vomiting may be associated
with episodes of aspiration so assess and if necesssary
correct respiratory function.
2. The oesophageal lumen becomes rapidly contami-
nated in the presence of disease or partial obstruction. For
24 h before operation give 10 ml of 0.2% chlorhexidine
mouthwash and swallow, 6-hour ly.
Liver, biliary and pancreatic operations
1. Jaundiced patients may be deficient in the vitamin
K-dependent clotting factors II, V, VII, IX and X, resulting
in a bleeding tendency. Give vitamin K (10 mg intra-
muscularly or intravenously) to patients with obstructive
jaundice prior to surgery, if their prothrombin time is
abnormal. Be ready to give fresh frozen plasma to those
in whom there is a significant coagulopathy and who
require urgent operation.
2. Preoperative insertion of a biliary endoprosthesis to
correct obstructive jaundice in the hope of reducing oper-
ative risk is controversial. There is also little evidence that
routine preoperative biliary stenting or drainage by endo-
scopic retrograde cholangiopancreatoscopy (ERCP), or
percutaneous transhepatic cholangiography (PTC), is
helpful in these patients. However, consider preoperative
drainage in patients who are elderly, deeply jaundiced or
with biliary tract sepsis.
3. Avoid or reduce renal failure secondary to obstruc-
tive jaundice (hepatorenal syndrome) by ensuring ade-
quate preoperative hydration; do not stop oral fluids
pre-operatively without intravenous fluid replacement.
The value of the osmotic diuretic mannitol and the
ino trope dopamine (in a low dose resulting in renal
vasodilatation) to prevent hepatorenal failure is unproven.
4. Infective complications are common after operations
for obstructive jaundice, so always give antibiotics as
prophylaxis.
5. Acute cholangitis demands systemic administration
of fluids, antibiotics and urgent biliary tract drainage,
either endoscopically or percutaneously. Patients with
biliary obstruction who undergo an unsuccessful ERCP
(where the duct is entered but not stented) are at a high
risk of developing cholangitis. They require antibiotic
cover and urgent consideration of a PTC.
6. If you intend that the procedure will be carried out
laparoscopically on a patient with severe pulmonary
disease, take advice from the anaesthetist. Inducing
pneumoperitoneum increases intra-abdominal pressure
and may render ventilation difficult.
Key point
Before laparoscopic biliary operations, inform
the patient about the possibility of conversion
to an open procedure.
169
15*
PREPARATIONS FOR SURGERY
7. Hepatic cirrhosis is a particularly high risk disorder,
requiring treatment by an experienced team. Clotting is
often deranged, and may need elective correction with
vitamin K or emergency infusion of fresh frozen plasma
and clotting factors.
8. The presence of portal hypertension raises operative
risks. The operation may be technically difficult, with
excessive venous bleeding. Patients tolerate major fluid
shifts badly and become encephalopathy as a conse-
quence, or may develop renal failure. Avoid operating on
those with decompensated cirrhosis (Child-Pugh C)
unless it is absolutely essential.
9. In patients requiring pancreatic resection, consider
giving octreotide (a somatostatin analogue that suppresses
pancreatic secretion) in the perioperative phase to reduce
the risk of leakage from the pancreatojejunal anastomosis.
Several trials have shown probable but not certain benefit.
In operations on the pancreatic tail, with the possibility of
splenectomy, be prepared to inject the patient preoper-
atively with vaccines against pneumococcal, meningococcal
and Haemophilus influenzae type B infections.
Endocrine surgery
1. Thyrotoxic patients require preoperative treatment
to reduce thyroid activity, such as carbimazole 10-15 mg
three times daily, and a beta blocker such as propranolol
20-40 mg, 8-hourly for 10 days preoperatively, to prevent
thyrotoxic crisis.
2. Have the movement of the vocal cords checked by
indirect laryngoscopy prior to operation, to exclude an
unsuspected idiopathic unilateral palsy.
3. Demonstrate the extent of a retrosternal goitre with
computed tomography.
4. Patients with phaeochromocytoma require preoper-
ative medication to block the a- and p-adrenergic effects
of catecholamines, and may require admission a week
before operation. As a rule, start with a-blockade using
phenoxybenzamine, followed 48 h later by (3-blockade
with atenolol or metoprolol.
Paediatric patients
1. The common surgical procedures in childhood are
often performed by general surgeons with special train-
ing and interest in paediatric surgery. Complex congeni-
tal defects and surgery in neonates require specialist
surgical expertise and specific preoperative preparation.
■■*►
Key point
Manage all paediatric patients together with a
paediatrician.
2. Although comorbidity is unusual in children,
exclude upper respiratory tract infection or cold, which
can cause potentially life-threatening laryngeal spasm
due to the sensitivity of the inflamed airway. Discuss this
with the anaesthetist and be willing to postpone any but
an emergency operation.
3. Arrange elective procedures for children at the
beginning of the operating list to minimize the period of
fasting. If operation is delayed, give fluids intra-
venously; insert venous cannulae after applying topical
anaesthetic cream to reduce discomfort. Administer
fluids according to body weight (40-60 ml kg^ 1 24 h" 1 ).
Heparin and antibiotics are not required for routine
clean surgical procedures.
Thoracic surgery
1 . Arrange preoperative lung function tests in patients
with severe functional limitation due to chronic airway
disease, including arterial blood gases on room air and
measurements of forced expiratory volume in 1 min
(FEV}) and forced vital capacity (FVC). Patients with
FEVj/FVC below 50% of the predicted value are at a high
risk of respiratory failure.
2. In patients requiring lung resection, assess the likely
impact of this on postoperative lung function using
radioactive isotope perfusion scans of the individual
lungs.
3. Arrange active preoperative physiotherapy, treat-
ment of any respiratory infection with antibiotics and
good postoperative analgesia in order to minimize the
risk of postoperative respiratory failure. In this patient
group, seek evidence of associated atherosclerotic coron-
ary and cerebral vascular disease and obtain the advice of
a cardiologist if necessary (Goldman et al 1977).
4. Anticipate the possibility of pulmonary emboli and
give routine subcutaneous heparin.
Vascular surgery
1. Atherosclerosis is a generalized disease so search
carefully the complete vascular system for evidence of
widespread insufficiency, such as cerebral, coronary, renal
and peripheral arterial disease. Arrange for expert advice
and management before undertaking any operation for
peripheral vascular disease. In elective circumstances be
willing to await improvement of severe ischaemic heart
disease with drugs, angioplasty or coronary artery graft-
ing. An operation within 3 months of a myocardial infarc-
tion carries a 20-30% risk of a perioperative infarct. This
risk decreases to 10-20% between 3 and 6 months, and
4-5% after 6 months. This compares with a risk of 0.1-0.2%
risk of infarction in patients with no evidence of a
previous myocardial infarct. Remember that the risk of
170
PREOPERATIVE PREPARATION FOR SURGERY
15
death from perioperative myocardial infarction is
extremely high, at around 70%.
2. Diabetic patients with limb ischaemia require dia-
betes control and treatment of infected skin lesions before
operation.
3. Since smoking is a common predisposing factor to
atherosclerosis and it reduces small vessel blood flow, ask
the patient to stop it preoperatively. Smoking also pre-
disposes to chronic obstructive airways disease and
bronchial carcinoma, so carefully assess respiratory func-
tion. If there is a productive cough, send sputum for
culture, antibiotic sensitivity and cytology. In addition,
check the serum lipid profile to exclude correctable
hyperlipidaemia.
Orthopaedic surgery
1. The most common orthopaedic operations are for
the treatment of joint abnormalities secondary to
osteoarthritis. Many patients are elderly, with comorbid-
ity such as ischaemic heart disease and chronic obstruc-
tive airways disease. Diagnose, assess and treat them
appropriately (see Ch. 6).
2. Crossmatch blood for joint replacement as there
may be significant blood loss.
3. The increased use of prostheses (Greek pros = to +
thesis = putting) in orthopaedic surgery allows early
mobilization, but infection is a serious risk around the
foreign material. Administer antibiotic prophylaxis
against contamination from skin commensals such as
staphylococci and streptococci.
4. Since thromboembolism is a major cause of mortal-
ity in orthopaedic patients, especially following pelvic
surgery, routinely give prophylaxis with standard
heparin or LMWH.
Patients with latex allergy
Latex allergy is becoming more prevalent and is thought
to result from true anaphylaxis to latex proteins. It can
pose a serious risk to life from both anaesthetic and sur-
gical equipment. There is an increased incidence in those
exposed repeatedly to latex, such as healthcare workers,
patients with spina bifida who have had repeated
catheterization, atopic (Greek atopia = strangeness; hyper-
sensitivity) individuals and people with banana or
avocado allergy (crossreactiviry with similar proteins).
Plan operations on these patients so that all concerned in
the operating theatre and hospital ward use appropriate
equipment. The operating theatre should have a checklist
of equipment that is safe to use in such patients, and
ideally there should be a 'latex allergy box' containing
most of these items.
Summary
• Do you realize the importance of
preoperative preparation with close
attention to detail?
• Are you aware of the specific needs of
different patients undergoing different
procedures?
• Can you recognize the need to identify
high risk patients early so you can institute
appropriate measures at once?
• Do you accept the need for a
multidisciplinary approach, requiring good
communication within the team?
References
Campling EA, Devlin HB, Hoile RW, Lunn JN 1993 Report of
the national confidential enquiry into perioperative deaths
1991/1992. King's Fund Publishing, London
Cogo A, Bernardi E, Prandoni P et al 1994 Acquired risk factors
for deep vein thrombosis in symptomatic outpatients.
Archives of Internal Medicine 154: 164-168
Goldman L, Caldera DL, Nussbaum SR 1977 Multifactorial
index of cardiac risk in noncardiac procedures. New England
Journal of Medicine 297: 845-850
Knaus WA, Draper EA, Wagner DP et al 1985 APACHE II: a
severity of disease classification system. Critical Care
Medicine 13: 818-824
Rodgers A, Walker N, Schug S et al 2000 Reduction of
postoperative mortality and morbidity with epidural or
spinal anaesthesia: results from overview of randomized
trials. BMJ 321: 1493-1497
Shoemaker WC, Appel PL, Kram HB et al 1988 Prospective trial
of supranormal values for survivors as therapeutic goals in
high-risk surgical patients. Chest 94:1176-1186
Takala J, Meier-Hellman A, Eddlston J et al 2000 Effect of
dopexamine on outcome after major abdominal surgery: a
prospective, randomized, controlled multicentre study.
Critical Care Medicine 28 : 341 7-3423
Velanovich V 1994 Preoperative laboratory screening based on
age, gender and concomitant medical diseases. Surgery
115: 56-61
Wheatley T, Veitch PS 1997 Recent advances in prophylaxis
against deep vein thrombosis. British Journal of Anaesthesia
78: 118-120
Wilson J, Woods I, Fawcett J et al 1999 Reducing the risk of
major elective surgery: randomized controlled trial of
preoperative optimization of oxygen delivery. BMJ 318:
1099-1103
171
Preoperative assessment and
anaesthesia
M. 1/1/. Piatt
Objectives
Understand the rote of the preoperative
assessment in the work-up for surgery.
Gain a general understanding of the
function of the anaesthetist, the effects of
anaesthesia and the perioperative medical
management of the patient.
Realize the importance of analgesia in
minimizing the stress response and its
significance in reducing postoperative
complications.
Understand the basic pharmacology and
toxicology of local anaesthetic agents and
their use.
PREOPERATIVE ASSESSMENT AND
PREMEDj™
Ideally, an anaesthetist should assess all patients preop-
eratively. Often, daycare (or ambulatory care) patients
attend the hospital only on the morning of operation.
The anaesthetist carries out the assessment in the ward
just before the list begins, or even in the anaesthetic
room. Patients with significant intercurrent disease have
normally been assessed at a booking clinic and admitted
before the day of surgery to optimize their physical state.
An anaesthetist is usually asked to assess risk factors
involved.
The anaesthetic assessment evaluates the patient's
physiological status, vital organ functional reserve and
any concurrent disease states, including diabetes, thyroid
and cardiac diseases (see Chs 6, 15). This is in order to
judge the patient's ability to withstand the stress of
surgery and anaesthesia, and to check that the patient
has not eaten or drunk for 4 h, although this is slightly
modified for young children by allowing clear, glucose-
containing fluids up to 2 h preoperatively. Physical exam-
ination focuses on the cardiovascular, respiratory, hepatic,
renal, and central nervous systems.
Key point
• Are there any drug allergies, intercurrent
medications, history of personal or family
anaesthetic problems?
The anaesthetist then prescribes premedication, the drugs
administered preoperatively, including any essential
intercurrent medication. They are usually prescribed by
the anaesthetist at the preoperative visit to allay anxiety,
relieve pain and, occasionally, to dry saliva and oral
secretions.
Intercurrent medication
Many patients requiring operation have other medical
problems that are treated by a variety of different drugs
(see Ch. 6). Especially consider those on antihypertensive
therapy, antiarrhythmic therapy, anticoagulation regi-
mens, oral or insulin therapy for diabetes, endocrine
replacement therapy (particularly thyroxin), adrenocorti-
cal replacement or augmentation therapy, asthma or
chronic obstructive airways disease treated with bron-
chodilators and allied drugs, cardiac failure therapy, and
those requiring diuretics. Because of fasting, or the oper-
ation itself, it may not be possible to continue the medi-
cation. Many drugs must be continued up to the time of
operation and some agents can be administered par-
enterally. Antihypertensives, anticonvulsants, antiar-
rhythmics and other essential medications can often be
given 2 h preoperatively with a small sip of water.
Anaesthetic premedication
Anxiolysis (Table 16.1)
Patients attending for surgery are normally anxious about
the outcome. They may have a fear of the unknown, of
pain, of dying, of cancer, or non-specific fears. Although
the preoperative visit by the anaesthetist does much to
allay anxiety by reducing the unknown element, waiting
for an operation may be unpleasant. Anxiolytics calm the
172
PREOPERATIVE ASSESSMENT AND ANAESTHESIA
16
Table 16.1 Anxiolytic agents in common use
Benzodiazepines
Diazepam
Temazepam
Lorazepam
Midazolam
0.05-03 mg kg ]
0.15-0,5 mg kg- 1
0.015-0.06 |±g kg" 1
0.07-0. OS mg kg" 1
Phen o Xh is zin es
Promethazine 0.2-0.5 mg kg _1
Prochlorperazine 0.1-02 mg kg" 1
36-200
5-20
10-20
0.5-2
8-12
a-12
patient and help to reduce time spent 'dwelling' on fears.
Agents specifically used for anxiolysis are the benzo-
diazepines, particularly the shorter-acting agents such as
temazepam, usually given orally 2h preoperatively.
Midazolam can be given intranasally, intramuscularly or
intravenously. It is a potent benzodiazepine and often
produces unconsciousness! Opioid analgesics calm and
sedate the patient and are used especially if analgesia is
required (see below).
Phenothiazines are usually given in combination with
an opioid. Promethazine is frequently combined with
pethidine. These agents are useful, especially in the
elderly, as they calm but do not oversedate. Pheno-
thiazines are also appropriate in atopic individuals, such
as asthmatics; their antihistaminic action may be useful.
Prochlorperazine has combined sedative and antiemetic
properties.
Analgesia (Table 16.2)
There are two main reasons for using opioid analgesia as
part of the anaesthetic premedication, apart from the
excellent sedative properties. These analgesics ease
patients with painful conditions such as fractured hips
and other types of trauma for comfortable transfer to
theatre. They also provide a continuous background of
analgesia to aid the anaesthetic and extend analgesia into
the postoperative period. Recent evidence suggests that
preoperative medication with analgesics such as opioids
or non-steroidal anti-inflammatory drugs reduces post-
operative analgesic requirements. Recent evidence also
suggests that preoperative administration of cyclo-
oxygenase (COX) 2 inhibitors, such as rofecoxib, can
significantly reduce postoperative pain, probably by
reducing neurosensitization by prostaglandin release.
Take care when using these drugs, as they can aggravate
renal failure and may cause gastric bleeding, although
this is much less than with COX 1 drugs.
Table 16.2 Analgesic agents in common use
:
Agent
Dose
(mg kg-1)
Approx. duration,
i.m, (h)
Morphine
Diamorphine
Papaveretum
0.1-0.2
0.05-0.1
0.2-0,4
4
4
3
Notes
1, Papaveretum is a mixture of alkaloids which
contains morphine (45-55% dry weight), codeine,
papaverine, thebaineand noscopine. It should not
be used in women of child-bearing aye, because
noscopine has been shown to be a gene toxin.
Papaveretum is most commonly used as a
premedication in combination with hyoscine, and
comes in a premixed ampoule containing
papaveretum 20 mg ml" 1 and hyoscine 0,4 mg ml \
2. Morphine, often used alone for both its sedative
and analgesic properties, is usually combined with a
drying agent such as atropine (also useful to
prevent bradycardia), or in combination with an
antiemetic drug.
Opioid premedication is usually combined with anti-
cholinergic agents, such as glycopyrrolate, to dry secre-
tions and, in the case of hyoscine, to potentiate sedation.
The choice of premedication depends very much on the
individual patient. A moribund patient does not benefit,
and may indeed suffer, from such side-effects as respira-
tory or cardiovascular depression. In contrast, a young,
fit, anxious patient could benefit from anxiolysis or seda-
tion, besides possible analgesic requirements, especially
in trauma.
Drying secretions (Table 16.3)
When ether anaesthesia was used, it was important to dry
oral secretions, because ether stimulates salivary secre-
tions on induction, with the risk of laryngospasm. With
modern anaesthesia it is less of a requirement, although
it may be useful to dry secretions before dental surgery,
Table 163 Drying agents in common use
Agent
Dose
(mg kg- 1 )
Approx. duration
J
i.v.
i.m
Atropine
Hyoscine
Glycopyrrolate
0.02
0.008
0.01
15-30 min
30-60 min
1-A h
2-4 h
4-6 h
6-8 h
1
173
16
PREPARATIONS FOR SURGERY
bronchoscopy, operations on the lung, and for paediatric
patients in whom salivation can be troublesome, In addi-
tion to drying secretions, muscarinic receptor antagonists
also prevent bradycardia, a common side-effect of general
anaesthesia, especially in very young children.
Hyoscine, in contrast to atropine, contributes to the
sedative properties of premedication. Glycopyrrolate
does not cross the blood-brain barrier, and is an inhibitor
of salivary secretions, with little effect on the vagus nerve
and hence on the heart rate. Atropine has also been shown
to have a small antiemetic effect, presumably by inhibit-
ing vagal activity, as well as a slight bronchodilator effect.
5. The advent of newer, more specifically acting agents,
such as the muscle relaxants, has enabled modern general
anaesthesia to be considered as a balance between the
triad of 'relaxation', 'analgesia' and 'hypnosis' (lack of
awareness).
Phases
A general anaesthetic may be considered in three phases,
analogous to an aircraft flight. I shall consider each part
of the triad separately, under the heading of each phase
of the anaesthetic.
GENERAL ANAESTHESIA
1. The anaesthetist is responsible for managing the
patient peroperatively. This includes managing acute
blood loss, maintaining normal cardiorespiratory physi-
ology and protecting organ function. It may include min-
imizing the stress response to surgery and the effects of
the stress hormones on organ function, such as the heart
and kidneys. General anaesthesia is a reversible, drug-
induced state of unresponsiveness to outside stimuli,
characterized by lack of awareness, by analgesia and
relaxation of striated muscle. Older agents such as ether
need to be given in high dosage, and take a long time for
induction and recovery.
2. The mechanisms of general anaesthesia are complex
and ill understood. Current knowledge suggests that
general anaesthesia is produced when certain molecules
interact with multiple hydrophobic pockets, often within
complex protein molecules, such as those forming part of
the potassium channel of a cell membrane, as well as
certain neuron receptors, such as those for the inhibitory
transmitter gamma-aminobutyric acid (GAB A). It is clear
that short-term memory mechanisms are disrupted, in
addition to 'normal' brain function. These changes are
completely reversible, as normal function resumes on
removal of the anaesthetic agents. General anaesthesia is
an 'all-or-none' phenomenon, as the patient is either
anaesthetized or not, with no in between state.
3. Deep anaesthesia obtunds (blunts) the neurohu-
moral stress response to surgery. Modern anaesthesia is
usually at a much lighter plane, and some responses may
be seen. Ultra short-acting opioids help inhibit the stress
response; this is believed to be better for the patient.
Alternatively, regional anaesthetic techniques prevent the
stress response by blocking afferent nerve fibres.
4. Sedation is not general anaesthesia. Agents used
include benzodiazepines (for example midazolam), or
propofol in subanaesthetic doses. The patient continues to
respond to spoken command, but may not remember the
procedure later.
Take off: induction of anaesthesia
1. Hypnosis (Greek hypnos = sleep) at induction of
anaesthesia. In the anaesthetic room patients are induced
using one of several intravenous anaesthetics. In approx-
imate order of frequency, those shown in Table 16.4 are
the most commonly used agents. When drugs are taken
up in the bloodstream, initial distribution is to Vessel-
rich' tissues and those taking a large fraction of the
cardiac output. Thus the brain, which is vessel-rich and
also taking a large fraction of the cardiac output, receives
a considerable portion of intravenous anaesthetic given as
a bolus. Subsequently, drugs diffuse out of the brain,
down a concentration gradient formed by the falling
blood concentration, and are redistributed to other vessel-
poor tissues. This results in an initial short redistribution
half-life. The longer elimination half-life of a drug repre-
sents its metabolism and elimination from the body. In
some instances, this can appear to take a long time, due
to the slow leaching out of drug from vessel-poor fat
tissues.
2. Thiopental, a very short-acting barbiturate, was the
first widely used intravenous induction agent. It was first
used to great effect on casualties from the bombing of
Pearl Harbor in 1942. However, its ability to depress the
myocardium was tragically evident in the deaths of young
sailors already shocked from hypovolemia. It was soon
Table 1 6.4
Anaesthetic
agents
Drug
Dose
Distribution
Elimination
Thiopental
(mg kg -1 )
3-5
half-life (min)
half-life (h)
3-14
5-17
Propofol
1-3
2-4
4-5
Etoimidate
0,3
2-6
1-5
Ketarnine
i.v.
1-2
10
2-3
i.m.
5-10
15
2-3
Midazolam
0.03-0.3
6-20
1-4
174
PREOPERATIVE ASSESSMENT AND ANAESTHESIA
16
appreciated that the dose should be reduced, giving only
enough to cause sleep (a 'sleep dose')/ titrated carefully for
each patient, especially those with a low cardiac reserve.
3. Propofol has a very short half-life, and is used partic-
ularly in daycase surgery, where rapid recovery is neces-
sary. It is also used to abate the effects of procedures
which occasionally cause laryngospasm, such as laryn-
geal mask placement and anal stretching. It is sometimes
infused intravenously to maintain anaesthesia, because of
its short half-life. The initial bolus of propofol sometimes
causes a profound fall in blood pressure and inhibits com-
pensatory increases in heart rate; this can be attenuated
by administering glycopyrrolate or atropine before the
induction. Small doses of propofol are sometimes used to
produce sedation for procedures carried out under local
anaesthetic.
4. Etomidate is indicated only for induction of anaes-
thesia. As a side-effect, it causes a reversible suppression
of an enzyme in the adrenal cortex, leading to inhibition
of Cortisol secretion - this is especially important if it is
used as an infusion. It is indicated in patients with poor
cardiac reserve, or those in whom a fall in cardiac output
could prove catastrophic, because it tends to maintain
cardiac output. It is relatively long acting, and may cause
postoperative nausea and vomiting.
5. Ketamirte, structurally related to LSD, is used in
shocked patients because it stimulates the sympathetic
nervous system and prevents a fall in cardiac output.
However, patients who are already on full sympathetic
drive still suffer a reduction in cardiac output and blood
pressure. It produces a state known as 'dissociative
anaesthesia' with profound analgesia.
6. Benzodiazepines, and particularly midazolam, which
is the most efficacious in this respect when given intra-
venously, are occasionally used to induce or assist induc-
tion of anaesthesia and are commonly used for sedation.
7. Opioids in very high doses are used to induce anaes-
thesia in some situations. The most commonly used
agents for this are the highly potent synthetic derivatives
fentanyl, alfentanil and sufentanil. Fentanyl is used in a
dosage of up to 1.0 mg kg -1 , particularly in cardiac anaes-
thesia, as it avoids hypotension and maintains cardiac
output. Unless other agents are added, awareness may
occur. Chest rigidity, preventing adequate ventilation,
occasionally occurs but is easily reversed using muscle
relaxants.
Key point
Apart from the exceptions mentioned, all
intravenous anaesthetic agents depress the
myocardium.
Relaxation at induction
Muscle relaxation is necessary at induction to facilitate
tracheal intubation. Relaxation during maintenance of
anaesthesia is discussed below.
Suxamethonium is a depolarizing relaxant used primar-
ily for difficult intubation and crash induction. It lasts
only approximately 5 min following a dose of 1 .5 mg kg" 1 .
It is essentially two acetylcholine molecules joined
together. This similarity to acetylcholine results in activa-
tion of the receptor and depolarization of the muscle
membrane, lasting some 5—10 min, and muscles become
unresponsive to acetylcholine. Because of its short action
it is useful, apart from intubation, for very short surgical
procedures. Side-effects include the following.
• Histamine release. 'Scoline rash' is very common fol-
lowing intravenous administration of suxamethonium.
An erythematous rash is seen spreading over the upper
trunk and lower neck anteriorly. Very occasionally,
suxamethonium will cause bronchospasm and other
more severe sequelae.
• Bradycardia (Greek bradys = slow) occurs particularly
if a second or subsequent dose is given, especially in
children. Give atropine to prevent or reverse this effect.
• Generalized somatic pain of unknown cause may
result from widespread fleeting muscle contractions,
termed 'fasciculations', caused by the depolarization of
muscle fascicles.
• Hyperkalemia (Greek kalium - potassium) results
because suxamethonium causes the release of potas-
sium from muscle cells and can lead to cardiac arrest
• Persistent neuromuscular blockade may occur from the
genetically related deficiency or abnormality of plasma
pseudocholinesterase. The result is prolonged action of
suxamethonium, sometimes called 'scoline apnoea'.
The completely silent gene is rare, occurring in approx-
imately 1:7000 of the population.
• Malignant hyperthermia occurs in some 1:100 000 of
the population. It is a reaction to certain anaesthetic
drugs, of which suxamethonium and halothane are the
commonest. Muscle metabolism becomes uncontrolled
because of an abnormality of intracellular calcium flux.
Body temperature rises at the rate of at least 2°C every
15 min, and Paco 2 , reflecting the massively raised
metabolic rate, also increases with alacrity. Treat with
ventilation, surface cooling and intravenous dantrolene
sodium (Dantrium), given promptly before death
ensues.
'Crash induction'
1, This is necessary when you assume that the patient
has a full stomach (see below). The technique consists of
a rapid-sequence intravenous induction, cricoid pressure
175
16 .
PREPARATIONS FOR SURGERY
and tracheal intubation, with the aim of preventing regur-
gitation and aspiration of stomach contents.
2. Immediately following a preplanned dose of thiopen-
tal (3-5 mg kg -1 ), give suxamethonium (1.5 mg kg" 1 )/ cur-
rently the fastest muscle relaxant, acting within one
circulation time. Rocuronium, a newer non-depolarizing
relaxant, is also used, but has a longer duration of action.
Have a trained assistant apply pressure to the cricoid
cartilage, simultaneously compressing the oesophagus
between the cricoid ring and the vertebral column.
Intubate the trachea with a cuffed tube, and inflate the cuff.
When the anaesthetic circuit is attached and cuff seal con-
firmed/ only then have the cricoid pressure relaxed.
3. The following patients are at risk of aspiration of
stomach contents on induction of anaesthesia:
a. All non-fasted patients
b. Patients with a history suggestive of hiatus hernia
c. In an emergency, any traumatized patient, as trauma
slows stomach emptying
d. Those with intestinal or gastric obstruction or stasis
e. Pregnant women in whom stomach emptying is
slowed and the cardiac sphincter relaxed
f. Those with intra-abdominal tumours that may slow
gastric emptying.
'Cruising': maintenance of anaesthesia
1. Hypnosis during anaesthesia is usually maintained
with volatile agents/ which are hydrocarbons/ liquid at
room temperature/ with high saturated vapour pressures
and lipid solubility. Diethyl ether, inflammable and explo-
sive, was the earliest agent used, and is still popular in
some parts of the world. The addition of fluoride and
other halogens makes the hydrocarbon molecule much
more stable. Modern agents are non-flammable, non-
explosive, and much more potent than ether. Being less
soluble in blood, as indicated by the blood /gas partition
coefficient, they also have a much faster uptake and elim-
ination time than diethyl ether. Table 16.5 shows the most
commonly used anaesthetic volatile agents, with ether as
a comparison.
2. Halothane is a hydrocarbon with fluorine, chlorine
and bromine atoms. It was the first modern volatile
non-flammable and non-explosive anaesthetic agent.
Synthesized in 1951 and first used clinically in 1956, it
was the most commonly used anaesthetic agent for
30 years. It is a potent anaesthetic, allowing a smooth
induction, especially important for gaseous induction of
children, and with relatively rapid onset of anaesthesia.
In the body up to 20% is metabolized by the liver, the
majority being eliminated unchanged via the lungs. The
recovery time from halothane anaesthesia is also rela-
tively brisk and smooth. The most common side-effects of
halothane result from its effects on the heart, Halothane
Table 16,5
Anaesthetic volatile
agents
Agent
Structure
MAC
Blood/gas
partition
coefficient
Diethyl ethe
r ChbCtVO-CHjCHb
1.92
12
Halothane
CF 3 CHCIBr
0,75
2.3
Enflurane
CHF ? 0-CF,CHFCI
168
19
Isoflurane
CHF ; 0-CHClCFj
K05
1.4
Sevoflurane
(CF^CHO-CF^F
2.0
0,6
Desflurane
CF 3 CfHO-CF>H
6-9
0.42
Xenon
Xe
71
0.14
A/ores
1. MAC: the minimum alveolar concentration of a
gas or vapour in oxygen required to keep 50% of
the population unresponsive to a standard surgical
stimulus (opening of the abdomen). MAC is
expressed as a percentage concentration.
2. Blood/gas partition coefficient: indicates how
rapidly a gas or vapour is taken up from the lungs.
The higher the blood solubility, the longer it takes
for the brain to gain adequate anaesthetic
concentrations.
3. Summary of effects of modern vapours on organ
systems:
a. Heart: generally cause depressed contractility:
halothane > enflurane > isoflurane
(halothane causes more arrhythmias)
b. Blood vessefy. generally cause vasodilation:
isoflurane > enflurane > halothane
c Respiration: depressed by al\ agents;
enflurane > isoflurane > halothane
d. Brain: all may cause vasodilation and raised
intracranial pressure: halothane > enflurane >
isoflurane (isoflurane safe up to 1 MAC),
slows the sinoatrial node, slowing heart rate and causing
variations in the PQ interval. It reduces myocardial work-
load. Like verapamil, halothane produces these effects by
blocking calcium channels in the heart. However, it also
sensitizes the heart to catecholamines and may precipi-
tate arrhythmias - especially important in the presence of
adrenaline (epinephrine)-supplemented local anaesthesia
and if the arterial carbon dioxide tension, Paco 2/ is
elevated. By reducing cardiac output, halothane attenu-
ates splanchnic blood flow, diminishing hepatic blood
flow and possibly aggravating its effects on the liver.
With the aid of very fine indicators of hepatic perfor-
mance, it has been shown that even the briefest exposure
to halothane causes some degree of liver dysfunction,
probably related to the large amount, up to 20%, of
halothane that is metabolized. An idiosyncratic (Greek
idios - one's own + syn = together + krasis = a mixing;
176
PREOPERATIVE ASSESSMENT AND ANAESTHESIA
16
hence a personal peculiarity), reaction, which occurs after
halothane exposure in some patients, is known as
'halothane hepatitis'; it is a fulminant centrilobular
hepatic necrosis which appears 2-5 days postoperatively.
The incidence is 1:35 000 of the population (National
Halothane Study USA, 1966), with a mortality of over
50%. Halothane is now used in only 10% of anaesthetics
given in the UK, mainly for paediatric anaesthesia.
3. Enflurane is an ether synthesized in 1963 and first
used in 1966. It is halogenated with fluorine and chlorine
atoms to render it non-explosive and non-flammable.
Enflurane is more efficacious in reducing peripheral vas-
cular resistance and is less likely to cause cardiac arrhyth-
mias, nor does it sensitize the heart to catecholamines;
however, its pungent odour makes it unsuitable for
gaseous induction in children. Enflurane causes greater
respiratory depression than halothane or isoflurane, and
so it is less suitable for maintaining anaesthesia in the
spontaneously breathing patient. Enflurane is only
slightly metabolized by the liver (up to 2.5%) and appears
not to cause hepatitis.
4. Isoflurane was synthesized in 1965 and first used in
1971. It is a structural isomer of enflurane, but with dif-
ferent properties. Isoflurane tends to act on the peripheral
vasculature as a calcium antagonist, reducing peripheral
vascular resistance. Although it has minimal effects on the
heart, isoflurane may cause 'coronary steal', whereby
blood is diverted from stenosed coronary arteries to
dilated unblocked coronary arteries, possibly compro-
mising ischaemic areas of myocardium. This is still a con-
troversial area and isoflurane generally causes minimal
depression of contractility. In the brain, isoflurane has the
least effect on cerebral blood flow, causing no significant
increase up to 1 MAC (minimum alveolar concentration).
Isoflurane causes least respiratory depression and is
suited to the spontaneously breathing patient. Up to 0.2%
only of isoflurane is metabolized by the liver and no cases
of hepatitis have been reported.
5. Desflurane is popular for anaesthetizing daycare
patients because of the rapid recovery; however, it is very
pungent, often causing patients to cough, so it is unsuit-
able for gaseous induction. It is useful for patients with
large amounts of adipose tissue, as it has the lowest fat
solubility of all the agents used, resulting in a more rapid
recovery, with little accumulation.
6. Sevoflurane is very popular as a gaseous induction
agent, especially in children, because of its rapid onset and
non-pungent characteristics. It has a low volatility, so is
cheaper to use at low gas flow rates, as less liquid is used.
It is now probably the most commonly used anaesthetic
agent. Both desflurane and sevoflurane are characterized
by remarkable molecular stability, with very little hepatic
metabolism. They also have a very low blood gas solubil-
ity coefficient, resulting in very rapid onset and recovery.
7. Xenon (Greek xenos = stranger, guest), a rare, heavy
gas, is currently under trial as an anaesthetic agent. It is
an extremely stable molecule and gives excellent cardio-
vascular stability with a rapid onset and offset, and no
metabolism. However, it is very expensive and has
required the development of special anaesthetic machines
which allow the gas to be recycled for further use.
8. Nitrous oxide (N z O), unlike the volatile agents, is a gas
at atmospheric pressure and room temperature. It has a
MAC of 103% at sea level. The requirements of keeping the
patient well oxygenated mean that it can never be relied
upon to provide anaesthesia in its own right. It is, however,
a very potent analgesic agent. Fifty per cent N 2 is equiva-
lent in efficacy to approximately 10 mg morphine sulphate.
It continues to enjoy popularity as the main background
anaesthetic gas, usually given as 70% in oxygen. In concen-
trations greater than 50% it causes amnesia and contributes
significantly to the overall anaesthetic.
9. General anaesthesia can also be maintained intra-
venously using a continuous infusion of anaesthetic agents
such as propofol, which are non-cumulative and are rapidly
cleared. This is usually supplemented with an infusion of a
short-acting opioid such as remifentanil or alfentanil. This
is termed 'total intravenous anaesthesia (TIVA)'.
Relaxation during anaesthesia
1 . To allow the surgeon access to intra-abdominal con-
tents, or to allow artificial ventilation of the patient in
chest surgery, for example, muscle relaxation (paralysis)
is required.
2. Agents used specifically to relax muscles are called
relaxants; they are agents which block acetylcholine
receptors on muscle endplates. There are two types of
relaxant:
a. Depolarizing muscle relaxants. The only one still in
common use is suxamethonium, which is described
above in relation to induction.
b. Non-depolarizing muscle relaxants. There are many
different relaxants available today. Because of the side-
effects of suxamethonium, researchers continue to seek a
non-depolarizing relaxant with a very rapid onset and
very short half-life. They have a usual onset time of
2-3 min, and last from 20 to 60 min. They are competitive
inhibitors of the acetylcholine receptors on muscle end-
plates, preventing access of acetylcholine to receptor,
blocking transmission of nerve impulse to muscle. Curare
was the first relaxant of this class, developed from an
arrow poison used by the indigenous people of the
Amazonian rainforests to kill animals for food. The dex-
trorotatory isomer alone is active; the term 'tubo-' refers to
the bamboo tubes in which it is carried - D-tubocurarine.
Modern relaxants tend to be shorter acting, with fewer
side-effects (Table 16.6).
177
11_
PREPARATIONS FOR SURGERY
Table 16.6 Non-depolarizing muscle relaxants
Agents
Dose (mg kg 1 ) Duration of effect (min) Side effects
Pancuronium
0.01
45-120
Vecuronium
0.01
30-45
Rocuronlum
0.05
30^5
Atracurium
0.06
15-40
Cisatracurium
0.15
30-45
Vagolytic: tachycardia, increases blood pressure
Bradycardia
Rapid onset
Histamine release
No histamine release
Notes
1 > With the exception of atracurium and cisatracurium, ail these agents require renal and hepatic function for
their clearance.
2. Atracurium and cisatracurium are excreted by two mechanisms: Hoffman elimination (up to 40% with
atracurium, up to 70% with cisatracurium) and hepatic metabolism. Hoffman elimination results in breakdown of
the molecule as a result of pH and temperature. It is used in those patients with renal failure.
3. The duration of effect with each agent varies slightly according to anaesthetic technique. The use of volatile
agents, particularly enflurane and isoflurane, potentiates the effect of non-depolarizing muscle relaxants.
Hypothermia also potentiates non-depolarizing relaxants.
4. The shorter-acting agents atracurium and vecuronium are often used as infusions for long cases and in
intensive care.
5. Muscle relaxants have no intrinsic anaesthetic effect.
Analgesia during anaesthesia
The final part of the triad of general anaesthesia during
its maintenance consists of analgesia. The anaesthetized
patient derives analgesia from three potential sources:
from the premedication/ from anaesthesia supplementa-
tion with opioids, and from the analgesic properties of
volatile and gaseous agents.
1 . Premedication. Opioids used in premedication, as dis-
cussed earlier, tend to last intraoperatively and into the
postoperative period. In this way, premedication affects
both the anaesthetic and postoperative analgesia.
2. Anaesthetic opioid supplementation is often adminis-
tered intraoperatively to deepen the effect of the anaes-
thetic, or to reduce the amount of volatile agent used
(often because of their side-effects such as hypotension).
To limit the effects of opioids to the perioperative period,
anaesthetists often use highly potent short-acting agents
such as fentanyl, alfentanil or sufentanil. Recently, the
ultrashort-acting remifentanil has become available, and
is given only by infusion. These agents are all much more
potent than morphine, and much shorter acting, of the
order 20-30 min. They may need to be reversed at the end
of the operation, to facilitate spontaneous respiration.
However, this is at the expense of analgesia. Longer
acting opioids such as morphine, papaveretum or pethi-
dine may also be used, especially if postoperative
analgesia may be a problem.
Modern non-steroidal anti-inflammatory agents, such as
diclofenac, are used for postoperative analgesia, either on
their own for minor surgery or in combination with opioid
techniques to give a much better quality of analgesia. Side-
effects include renal failure (prostaglandin inhibition may
lead to renal shutdown), gastric ulceration and bleeding
(inhibition of platelet function). Different agents have dif-
ferent degrees of complications, but their careful use has
revolutionized the aftercare of patients, particularly after
daycare surgery. The development of COX 2 antagonists,
such as rofecoxib, will reduce the problems of gastric
bleeding but will still be a problem for renal function.
3. Analgesic properties of volatile agents. Modern volatile
anaesthetic agents have poor analgesic properties and
contribute little to this part of the anaesthetic. However,
nitrous oxide is a very good analgesic (see above) and is
also used for analgesia during labour as a 50% mixture
with oxygen, known as Entonox.
'Landing': recovery from anaesthesia
At the end of the operation, anaesthesia is terminated.
Volatile agents and nitrous oxide are turned off on the
anaesthetic machine and oxygen alone administered.
Anaesthetic gases and vapours diffuse down concentra-
tion gradients from the tissues to the alveoli of the lungs
and out via the airway.
1. Reversal of muscle relaxation: competitive muscle
relaxants usually need to be reversed to ensure full return
of muscle power. The degree of neuromuscular blockade
can be monitored with a peripheral nerve stimulator.
178
PREOPERATIVE ASSESSMENT AND ANAESTHESIA
f 16
2. Neostigmine (0.05 mg kg -1 ) or edrophonium
(0.5 mg kg -1 ) is given intravenously. They block acetyl-
cholinesterase in the neuromuscular junction, resulting
in accumulation of acetylcholine. This overcomes the
competitive blockade of the relaxant molecules in favour
of acetylcholine. However, both neostigmine and edro-
phonium cause acetylcholine accumulation at both
muscarinic and nicotinic sites. Muscarinic receptors are
those cholinergic receptors in the heart, gut, sweat
glands, etc. Therefore, to prevent bradycardia, profuse
sweating and gut overactivity, atropine (0.02 mg kg ] ) or
glycopyrrolate (0.01 mg kg~ ] ) must be given with the
anticholinesterase.
3. Full reversal of muscle relaxation is only apparent
from appropriate neuromuscular monitoring, or when the
patient is able to maintain head lifting. This aspect of
recovery from anaesthesia is crucial, as full muscular
control is necessary for coughing and for good control of
the airway. Indeed it highlights the importance of
adequate recovery facilities in the theatre suite.
POSTOPERATIVE ANALGESIA
It is important to continue good analgesia into the post-
operative period and to continue to have a stress-free
patient. The anaesthetist will usually ensure that suffi-
cient longer-acting opioid such as morphine or diamor-
phine has been administered towards the end of the
procedure for adequate postoperative analgesia. This can
be topped up as necessary in recovery. If an epidural or
other regional block such as a brachial plexus block is
sited, the analgesia can be continued with a continuous
infusion of local anaesthetic combined with a short-acting
opioid. The surgeon may be asked to inject local anaes-
thetic locally at the site of wounds to minimize postoper-
ative discomfort.
There are several methods of managing postoperative
pain, which can be considered as follows:
• Systemic analgesia: intravenous, intramuscular, sub-
cutaneous, oral, nasal or sublingual application of
analgesics
• Regional analgesia: usually placed before surgery, as
part of the anaesthetic technique - continued into post-
operative period
• Other techniques (TENS, acupuncture): not very effec-
tive for acute pain - used more for chronic pain.
Pre-emptive analgesia may reduce postoperative anal-
gesic requirements. This involves the preoperative
administration of: nerve blocks /regional analgesia; pre-
medication with opioids; use of supplementary agents
with specific spinal actions such as ot 2 -agonists.
The World Health Organization produced a simple
pain ladder for the administration of analgesia. Originally
designed for cancer pain, it is also appropriate for acute
postsurgical pain:
• Minor pain: paracetamol, aspirin, other non-steroidal
analgesics
• Moderate pain: above combined with minor opioids -
co-proxamol (propoxyphene), co-dydramol (codeine);
minor or intermediate opioids alone, e.g. tramadol,
buprenorphine
• Severe pain: opioids - morphine, diamorphine, oxy-
codone, etc.
The 'minor opioids' consist of propoxyphene, codeine
and tramadol. Propoxyphene and codeine are often com-
bined with paracetamol. Tramadol has the least effect on
respiratory depression and is not a class A drug. It is
roughly equivalent to codeine in its action.
The "intermediate opioids' mainly consist of buprenor-
phine, which is well absorbed sublingually.
The 'major opioids' include morphine, diamorphine
(heroin), oxycodone, fentanyl, sufentanil, alfentanil and
remifentanil.
The dose of the major opioids, of which morphine and
diamorphine are the most commonly used, is whatever is
required! The dosage should be carefully titrated intra-
venously. Long-term chronic and cancer pain in those
who can swallow can be titrated orally and converted to
long-acting drugs such as morphine continus tablets or
capsules. Initially, the required loading dose, titrated,
should be given. Care may need to be taken with subse-
quent dosage, especially in the elderly, as the half-life may
be extended. Opioids can be given by a number of differ-
ent routes: intravenous, intramuscular, infusion, regional
(including spinal). They may be used in combination
therapy with non-steroidal anti-inflammatory drugs, or
with local anaesthetics. Opioids act on \x & 8 receptors
in the brain and spinal cord. Mu receptors also cause
nausea, vomiting and respiratory depression. Delta
receptors are found mainly in the spinal cord.
Non-steroidal anti-inflammatory drugs block the cyclo-
oxygenase (COX) pathway. There are two forms of the
enzyme: COX 1 and COX 2. COX 1 is always present, but
COX 2 is only induced by inflammation, such as occurs
with surgery or in chronic inflammatory conditions. They
both also have a central role, where both COX 1 and COX
2 are found as neurotransmitters. COX 2 antagonists are
preferable where there is a high risk of peptic ulceration/
bleeding, however, there is still not a 100% guarantee!
Currently the second generation of COX 2 antagonists
are being released, some of which will be available for
parenteral administration, enabling easier peroperative
administration.
179
™ .
PREPARATIONS FOR SURGERY
REGIONAL ANAESTH^
1. Regional (local) anaesthesia is the reversible block-
ade of nerve conduction by regionally applied agents, for
the purpose of sensory ablation either of traumatized
tissue or to enable minor surgery. These agents are
referred to as 'local anaesthetics'. Both motor and
sensory nerves may be blocked, depending on the agent
used and the anatomical region where the agent is
applied.
2. Nerves may be blocked anywhere between the
central nervous system and the site of required sensory
loss. Local anaesthetics are used to block pain fibres as
they enter the spinal cord: epidural, spinal and paraver-
tebral techniques. They may also be blocked along their
anatomical route in the neurovascular bundles: field
blocks, or specific nerve blocks. Finally, local infiltration
around the required site may be performed (for example,
skin and subcutaneous infiltration) to block conduction at
the nerve endings.
3. Types of nerve fibre: the speed with which local
anaesthetic agents are taken up by nerve fibres depends
on their size and whether they are myelinated. Nerve
fibres are classified according to their size and speed of
conduction (Table 16.7).
4. Sensitivity to local anaesthetics: the smaller fibres are
more sensitive to local anaesthetic agents than the larger
fibres. Hence, 'C fibres conducting pain are more sensi-
tive than motor fibres in the 'A' group. This is why
patients may still be able to move limbs, even during
regional anaesthesia. The reason for the difference is most
likely to be due to more rapid absorption and uptake of
local anaesthetic into the smaller fibres within neuro-
vascular bundles.
Local anaesthetic agents
Drugs used as local anaesthetics all tend to have
'membrane-stabilizing' properties. They act by inducing
a blockade of nerve transmission in peripheral nerve
impulses. This occurs as a result of obstruction to sodium
channels in the axon membrane, preventing ingress of
sodium ions necessary for propagation of an action
potential.
Local anaesthetic agents belong to one of two chemical
classes according to their structure, which consists of an
amide or ester linkage separating an aromatic group and
an amine:
Aromatic group ±=r Amine group
Amide or ester
Ester class
The only ester still in frequent use is cocaine, which is an
ester of benzoic acid. It is generally used only for topical
anaesthesia of mucous membranes in the nose and
sinuses. Amethocaine is still used as a topical agent, as is
benzocaine.
Amide Class (Table 16.8)
• Lidocaine (lignocaine) was the first amide to be synthe-
sized. It was shown to be safer than cocaine and has
remained a mainstay for local anaesthetic practice. The
maximum dosage is 4 mg kg^ 1 alone or 7 mg kg -1 with
adrenaline (epinephrine).
• Prilocaine has the highest therapeutic index, and
is considered the safest agent for intravenous block-
ade. The maximum dose is 6 mg kg" 1 . Other amides in
common use include bupivacaine, levo-bupivacaine
and ropivacaine.
• Bupivacaine is longer acting than lignocaine and is com-
monly used in epidural analgesia.
• Levobupivacaine, the isomer, is safer than the racemic
bupivacaine in terms of cardiotoxicity and has a similar
dosage profile.
• Ropivacaine has less motor blockade than bupivacaine
when used epidurally.
Lidocaine (lignocaine), bupivacaine and levobupivacaine:
maximum dose 2 mg kg -1 .
Table 16.7 Types of nerve fibre
Fibre
B
C
Type
ft
P
y
a
Function
Conduction velocity (ms)
Motor, proprioception
70-120
Touch, pressure
30-70
Motor (spindles)
15-30
Pain, temperature, touch
12-30
Preganglionic autonomic
3-15
Dorsal root: pain, reflexes
0.5-2
Sympathetic: postganglionic
0,7-2.3
Diameter (^m)
12-20
5-12
3-6
2-5
<3
0.4-1
0.3-1
180
PREOPERATIVE ASSESSMENT AND ANAESTHESIA
.' 16
Table 16.8 Amide class
Drug
Maximum dose (nig)
Side effects
Lidocaine (lignocaine)
Prilocaine
Bupivacaine
Levobupivacaine
Ropivacaine
Cocaine
300 (500 + adr.)
600
175 (225 + adr.)
175 (225 + adr.)
2.5 per kg is recommended
(e.g. 30 mf of 5% ropivacaine
in a 60 kg patient)
150
No unusual features. CNS excitation with toxicity
Least toxic, Methaemoglobinaemra > 600 mg
Sudden cardiovascular collapse. Not indicated for
intravenous blockade
Less cardiotoxicity
Less motor blockade in epidural administration
Cardiac arrhythmias. CNS excitation. Topical use only
Notes
1, The table includes only those agents currently in common use and maximal doses relate to adult size (70 kg
body weight). The dosages in parentheses refer to maximal doses in the presence of adrenaline (epinephrine).
2, All local anaesthetic agents have membrane-stabilizing properties. Their toxic effects therefore relate to this
property and involve mainly the cardiovascular and central nervous systems.
Toxic effects on the central nervous system include fitting and coma, leading to death from hypoxia without
adequate resuscitation. Cardiovascular effects from toxicity include hypotension, cardiac arrhythmias and acute
cardiovascular collapse,
Bupivacaine has a high affinity for cardiac muscle cells - a property which is thought to be responsible for the
high incidence of cardiovascular collapse associated with its use for intravenous blockade {Bier's block), for which
it is no longer recommended,
3, Toxic effects may also occur with the accidental intravascular injection of drug.
4, Concentration of local anaesthetic agents varies. Bupivacaine and levobupivacaine comes as 0.5% or 0.25%,
with or without adrenaline (epinephrine), Lidocaine (lignocaine) generally comes as 0.5 r 1.0, 2.0%
concentrations, again plus or minus adrenaline (epinephrine). The higher concentrations obviously have lower
maximum safe volumes (1 % = 10 mg ml' 1 . 2% = 20 mg ml '),
5, Local anaesthesia techniques should always be performed where adequate resuscitation facilities are present,
6, Adrenaline (epinephrine) and other vasoconstricting agents, such as felypressin, allow higher doses of local
anaesthetic to be used, the vasconstriction resulting in reduced absorption.
Clinical application
1. Local infiltration is used for surgery alone or in
combination with general anaesthesia. Used with
adrenaline (epinephrine), it reduces bleeding at the oper-
ative site. It also produces good postoperative analgesia.
EMLA (eutectic mixture of local anaesthetics), a mixture
of lignocaine and prilocaine, produces good analgesia
when applied topically to skin. It is useful for insertion of
intravenous lines, arterial lines and removal of minor skin
lesions. It needs to be applied some 2 h before the proce-
dure. Tetracaine (amethocaine) 4% gel (Ametop) can also
be used in the same way.
2. 'Field 7 blocks and nerve blocks are useful for pro-
ducing wider areas of anaesthesia and analgesia, for
example in inguinal hernia repair, brachial plexus block-
ade for the upper limb, and femoral and sciatic blocks of
the lower limb.
3. Spinal, epidural and paravertebral blockade produce
widespread anaesthesia and analgesia. The pain of labour
and childbirth involves nerve roots of lower thoracic,
lumbar and sacral regions of the spinal cord. Epidural tech-
niques, involving the epidural placement of a catheter,
allow continuous analgesia or anaesthesia, alleviating pain
from all these groups o( fibres. Regional anaesthesia such
as this is frequently employed for urological and other
surgery in the lower half of the body It should be noted,
however, that spinal and epidural techniques also block
sympathetic ganglia at the appropriate levels. Hypotension
will occur unless adequate precautions are taken.
RECENT ADVANCES
1. Pre-emptive analgesia has gained popularity
with the recent publication of data suggesting that the
181
16
PREPARATIONS FOR SURGERY
administration of analgesia preoperatively, either sys-
temically as with an opioid, or regionally as in use of local
anaesthetic techniques, reduces the patient's need for
analgesia postoperatively. This has been reinforced by the
finding that using epidural analgesia for 3 days prior to
leg amputation produces a marked reduction in the inci-
dence of phantom limb pain. Thus the use of regional
techniques combined with general anaesthesia is becom-
ing more popular.
2. The widespread development of acute pain services
is enabling the continuation of regional local analgesic
techniques from the operating theatre into the general
wards, improving the standards of postoperative pain
control and perhaps reducing the incidence of postoper-
ative nausea and vomiting secondary to opioids.
Further reading
Atkinson RS, Rushman GB, Lee A 1987 A synopsis of
anaesthesia, 10th edn. Wright, London
Barash PG, Cuplen BF, Stoelting RK 1989 Clinical anaesthesia.
Lippincott, Philadelphia
Gilman AG, Goodman LS, Rail TW, Murad F 1985 Goodman
and Gilman's pharmacological basis of therapeutics, 7th edn.
Macmillan, London
Miller RD 1990 Anesthesia, 3rd edn. Churchill Livingstone,
Edinburgh, vols I — II
Nimmo WS, Smith G 1989 Anaesthesia. Blackwell Scientific,
Oxford, vols I-II
Stoelting RK 1987 Pharmacology and physiology in anesthetic
practice. Lippincott, Philadelphia
Vickers MD, Morgan M, Spencer PSJ 1991 Drugs in anaesthetic
practice, 7th edn. Butterworths, Oxford
Summary
• What are the risks of failure to carry out
preoperative assessment before an
anaesthetic is administered?
• Can you describe the functions of
premedication?
• What are the phases of general
anaesthesia? With what other activity has
it been compared?
• What is a 'crash' induction?
• What are the common types of local
anaesthetic? Do you know their maximal
dosage?
182
Operating theatres and
special equipment
M. K. H. Crumplin
Objectives
Learn the safe positioning, movement and
care of patients while they are
unconscious.
Respect and understand the principles of
diathermy, laser, cryosurgery and X-ray
usage in a theatre environment.
Comprehend principles of the use of all
equipment you use, including laparoscopic
insufflation principles and
instrumentation, fibreoptics and
microscopes.
Understand the prevention of sepsis in the
theatre.
OPERATING THEATRE DESIGN AND
ENVIRONMENT
Introduction
1 . A large proportion of your life is spent within the envi-
ronment of an operating theatre. There are physical chemi-
cal and infective hazards to yourself and your colleagues,
nurses and patients, thus making the operating department
the most hazardous part of the hospital. You must gain an
understanding of this environment and the risks to both
staff and patients. In the operating theatre the patient is
totally helpless, and under full control of the theatre staff.
2. The operating theatre environment must provide a
safe, efficient, user-friendly environment that is as free
from bacterial contamination as possible. Operating
suites should be sited near to each other for efficient flex-
ibility of staff movement, preferably on the first floor,
away from the main hospital traffic. They should be on
the same level as, and close to, intensive care units and
surgical wards. The suite should incorporate the theatre
sterile supply unit.
3. There should be minimum distance between operat-
ing rooms and the accident and emergency (A & E) unit
and X-ray facilities, which will both be sited on the ground
floor. Your hospital has a multidisciplinary user commit-
tee to optimize efficiency and safety, comprising surgeons,
anaesthetists, operating theatre and anaesthetic nurses,
microbiologists, a manager and a finance officer, in line
with updated Department of Health recommendations.
4. Operating theatres now have an incident reporting
system in place to audit adverse incidents in theatre. This
is not designed to be punitive (Latin punire = to punish),
but educational. Joint audit sessions between anaes-
thetists and surgeons allow adverse incidents to be dis-
cussed in an open and constructive way.
5. An attempt was made by the Department of Health
and Social Security in 1978 to introduce the nucleus
concept, providing hospitals with theatre suites appro-
priate to the average district general hospital require-
ments. Orthopaedic, cardiac, neurosurgical, laser and
other specialist requirements make it necessary to adjust
the standard design. Examples are the Charnley tent, con-
trolled areas for laser therapy, and the provision of a
pump preparation room beside a cardiac bypass theatre.
The antiseptic environment
Zones
• An outer, or general access zone for patient reception
area and general office.
• A clean, or limited access zone between the reception
bay and theatre suite, and dispersal areas, corridors
and staff rest room.
• Restricted access zone, for those properly clothed per-
sonnel engaged in operating theatre activities, includ-
ing the anaesthetic room, utility and 'scrub up' rooms.
• An aseptic or operating zone - the operating theatre.
Keep the number of people to a minimum, as the bac-
teriological count is related to the number of persons
and their movement.
Air flow
Directional air flow (laminar air flow) may be vertical or
horizontal. In addition to normal turbulent air flow
183
17
PREPARATIONS FOR SURGERY
through theatre, which is necessary to maintain humidity,
temperature and air circulation, an increased rate of air
change is necessary to reduce the number of contami-
nated particles over the patient, that is aerobic counts of
less than 35 microorganism-carrying particles per mm -3 .
Air is pumped into the room through niters and passed
out of vents in the walls of the operating room; it does not
return into the operating suite. Most theatres have 20-40
or more air changes per hour.
Operating suit and tent environment
In this system there is a high vertical laminar flow
within a tent or designated area marked on the floor, and
clean air from above the table is expelled down to floor
level in a funnel shape, thereby reducing contamination.
The number of air changes may be increased to
400-600 per hour or more in the vertical laminar flow
system of a Charnley tent. Orthopaedic surgeons may
wear airtight suits and helmets, and work in a high
velocity vertical air flow environment, which has limited
access to other personnel. By using suitable exhaust suits
and such tents, infection in hip replacement may be kept
as low as 0.5%.
Wearing of disposable, non-woven fabrics
Reusable, comfortable cotton operating gowns, sterilized
by heat, have the disadvantage that when they are wet,
bacteria can pass through onto the operative field.
Disposable gowns of less permeable fabrics reduce dis-
persal of bacteria-laden particles that may emanate (Latin
emanare = to flow) from the operating or nursing staff (see
Ch. 18). Optimally, everybody should wear these gowns,
but they are costly Although masks are not essential for
the surgeon or nurses, wear them when the patient is
particularly susceptible to infection, when a prosthesis is
being inserted, or when you or the nurse has an upper
respiratory tract infection.
Skin preparation
Prefer a non-spirit-based skin preparation such as
Betadine, to minimize the risk of explosion. If you shave
the patient, carry it out as late as possible. Skin drapes
have limited benefit in preventing wound infection but
help keep the skin towels in place. To prevent the ingress
of skin bacteria apply an iodine-impregnated adhesive
skin sheet.
Temperature and humidity control
These should be controlled as part of an integral air con-
ditioning system to maintain a comfortable atmosphere,
with a higher temperature for neonates, children, elderly
patients and if the operation is prolonged. The tempera-
ture range is 20-22°C (68-71 .6°F), with approximately
20-40 air changes per hour. Patients become hypothermic
if the temperature falls below 21 °C (69.8°F) during pro-
longed procedures. Reduce heat loss by laying warming
blankets on the sorbo-rubber table surface, wrap the
patient in aluminium foil and infuse warmed intravenous
fluids. Pass the blood, crystalloid or colloids through a
coiled plastic infusion pipe within a heated waterbath.
Minimize postoperative heat loss by wrapping the patient
in metal foil. Increasing the humidity to 50% reduces
cooling by evaporation.
OPERATING .JfMJ^_^___
Operating tables need to be heavy and stable, easily
manoeuvrable, comfortable for the patient and highly
adjustable in terms of positioning the patient correctly for
a particular operative procedure. There are two basic
types of operating table. Most commonly they are com-
pletely mobile, thus allowing replacement if necessary. A
second type has a fixed, permanently installed column in
the centre of the operating room on which a variety of
table tops can be mounted; they are usually expensive
and can be remotely controlled. The problem is that if a
fault develops the table and theatre will be out of service;
the advantage is that interchangeable table tops allow
efficient patient handling and flexible operating-room
scheduling.
Ensure that the surface is sympathetic to the contours
of the patient who is placed on it. This is achieved by
using soft, moveable, easily cleaned sorbo-rubber
padding that moulds to the patient. It raises the patient
clear of the metal table.
Key point
• It is imperative that no part of the patient
comes into contact with the metallic structure
of the table or any metal object attached to it.
There should be a radiolucent section on tables used for
general surgery and urology to allow for static X-ray films
or the use of an image intensifier. Built-in, adjustable
lumbar supports may be useful; alternatively, use par-
tially filled intravenous fluid bags. Make sure that motor-
ized or hand-operated controls are easily accessible. The
table should be capable of two-way tilt, and breaking at
its centre to allow operations such as lateral nephrectomy,
or jack-knife positioning. The bottom half of the table
184
OPERATING THEATRES AND SPECIAL EQUIPMENT
. 17
must be easily removed to allow various types of leg
support and stirrups to be employed for gynaecological,
urological, orthopaedic and pelvic operations. A variety
of armrests, screen support bars and shoulder and pelvic
supports should be available.
Safety
When using limb supports, avoid overstressing or pro-
ducing localized pressure upon joints, ligaments, nerves,
blood vessels, skin or any point of the patient's limbs.
Various nerves are at risk from injury or pressure due to
inappropriate positioning on the table. The brachial
plexus may be stretched during arm movements, the
ulnar nerve damaged at the elbow during pole insertion
into the canvas sheet before transferring the patient, and
the common fibular and saphenous nerves may be
damaged by pressure against a leg support bar.
Osteoarthrosis may be aggravated by rough handling
during transfer, excessive joint movement, or distortion
during the operative procedure, such as cervical exten-
sion during thyroid surgery.
Key point
• Before induction of anaesthesia, rehearse a
stressful position on the table with patients
suffering from spinal or joint disorders.
Be particularly careful when moving patients on and
off the operating table. Check that attached tubing will
not be dislodged. Transfer is best carried out using the
Patslide, a tough plastic board, which acts as a bridge, on
which the patient is slid from trolley to table, or vice
versa. At least three people should be involved in moving
an unconscious patient.
Remember your own comfort in theatre. Always have
the table adjusted so that you are not stooping or uncom-
fortable. You should have the table at such a height that
your elbows are flexed at about a right angle to your field
of work.
Operating table fixtures for specialist
procedures
Orthopaedic surgery
There is a great variety of limb attachments to an operat-
ing table, enabling circumferential access to a limb and
manoeuvrability, and also allowing the surgical team to
use the image intensifier following fixation or recon-
structive procedures.
Neurosurgery
Access to the cranial cavity may be optimized by having
the patient sit up, while keeping the head comfortably
fixed using an appropriate padded head support placed
opposite the surgical field.
Key points
Make sure the table is secure and the patient
is safely positioned before you start
operating.
Have the table at a comfortable height for
surgery.
SPECIAL EQUIPMENT
Tourniquets
Abuse of tourniquets may lead to vascular damage or
thrombosis. Soft tissue and nerve injury may also occur.
Avoid these problems by:
1. Exsanguinating the limb using an Esmarch bandage
2. Applying the tourniquet cuff over soft padding at the
appropriate site
3. Inflating the tourniquet above the systolic blood
pressure
4. Recording the time when the tourniquet is inflated
and not allowing it to remain inflated for more than
2h.
Diathermy
Principles and effects
A high frequency alternating current (AC) is passed
through body tissue; where the current is locally concen-
trated (a high current density), heat is produced, result-
ing in temperatures up to 1000°C. Low frequency
alternating current such as mains electricity (50 Hz),
causes stimulation of neuromuscular tissue. The severity
of the 'electrocution' depends on the current (amperes)
and its pathway through the body. Five to ten milliamps
(mA) can cause painful muscle contractions, while
80-100 mA passing through the heart causes ventricular
fibrillation. Increasing the current frequency reduces the
neuromuscular response; at current frequencies above
50 000 Hz (50 kHz) the response disappears. Surgical
diathermy involves current frequencies in the range
400 kHz to 10 MHz. Currents up to 500 mA may then be
safely passed through the patient. Heat is produced wher-
ever the current is locally concentrated.
185
17
PREPARATIONS FOR SURGERY
Fig. 17.1 Monopolar diathermy.
diathermy an arc can be struck only between the
limbs of the forceps. Increasingly, surgical dissection
is now carried out with diathermy and harmonic
scalpels.
It will not work when a haemostat has grasped a
vessel and is then touched with the active diathermy
electrode. Bipolar current passes directly from one
diathermy forceps limb to the other and no current
passes through the tissue held by the haemostats.
Monopolar and bipolar diathermy
Monopolar diathermy is the most common configuration
(Fig. 17.1). High frequency current from the diathermy
generator (or 'machine') is delivered to an active elec-
trode held by you. Current density is high where this
electrode touches body tissue, producing a pronounced
local heating effect. The current then spreads out through
the body, returning to the diathermy generator through
the patient plate electrode (incorrectly called the 'earth
plate'). Having shaved an area of skin, make sure that the
plate is in good contact over at least 70 cm 2 , and prefer-
ably more than twice this area, to ensure that the current
density at the plate is so low that there is minimal
heating.
I I Key point
• Misapplication of the patient plate is by far the
most common cause of inadvertent diathermy
burns.
Bipolar diathermy (Fig. 17.2) avoids the need for a plate
and uses considerably less power. You hold forceps con-
nected to the diathermy generator. The current passes
from one limb of the forceps through the contained piece
of tissue to be coagulated, and then back to the generator
through the other limb of the forceps. This inherently
safer system has not gained wide use for two main
reasons:
1 . It cannot be used for 'cutting' (see below), as this
involves a continuous arc (spark) between the active
electrode and the tissue involved. In bipolar
Fig. 17.2 Bipolar diathermy.
Cutting, coagulating and blend
For cutting, the generator produces a continuous output,
causing an arc to be struck between the active electrode
and tissue and creating temperatures up to 1000°C. Cell
water is instantly vaporized, causing tissue disruption
with some coagulation of bleeding vessels. Coagulating
diathermy current is a pulsed output resulting in desic-
cation (Latin sicca = dry) and the sealing of blood vessels
with the minimal tissue disruption. Most diathermy
generators have a 'blend' facility, functioning only when
in cutting mode, allowing a combination of cutting
and coagulation waveforms, increasing the degree of
haemostasis.
Earth-referenced and isolated diathermy
generators
Earth-referenced generators. Older diathermy
generators, some of which are still in everyday use, have
valves and spark gaps to generate high frequency current.
These unsophisticated circuits produce a wide frequency
range, which includes frequencies above 1 MHz, and
large earth leakage currents are unavoidable. The patient
plate on these generators is earthed via a capacitor. The
capacitor allows easy passage of high frequency current,
such as in diathermy, but presents a large resistance to
low frequency currents, such as mains electricity. (The
patient is therefore not earthed for mains (50 Hz) current
to reduce the risk of electrocution.)
As long as the patient plate is correctly applied, the
patient is kept at earth (zero) potential for alternate sites
such as electrocardiogram (ECG) electrodes or a drip
stand accidentally touching the patient's skin.
Unfortunately, if the patient plate is omitted, or has
become displaced, diathermy current will still flow
(though a higher setting may be required) using the ECG
electrodes or drip stand for the return pathway. An ECG
electrode or drip stand presents skin contact of 1-5 cm 2 ,
so a severe burn is inevitable.
Isolated generators. The more modern, often
smaller, generators use transistors and 'solid-state' cir-
cuitry to produce the high-frequency current. Sophisticated
electronics result in a much tighter frequency range
186
OPERATING THEATRES AND SPECIAL EQUIPMENT
17
(400-600 kHz) and a considerable reduction in earth
leakage currents. Some of these solid-state generators (but
by no means all) are designated 'isolated': the diathermy
circuit is not earthed. This type of generator is inherently
safer than an earth-referenced machine. Diathermy current
can only pass back to the generator via the patient plate;
there is no pathway back via earth. If the plate is omitted,
no current will flow.
Safety
General safety. Ensure that whenever electrical
equipment is to be used on patients it meets the required
safety standards and is properly maintained. Everyone
using the equipment should be properly trained in its use.
At the very least, you should read the user's manual: all
diathermy machines are supplied with one.
Responsibility. The decision about who has overall
responsibility for surgical diathermy is often ignored until
a diathermy disaster occurs. The diathermy is set up by
nurses or operating department orderlies and the anaes-
thetist is usually the only doctor present when the patient
plate is applied. Few surgeons check the diathermy before
use.
e
Key points
• You are responsible for using this equipment
correctly. Check the alarm wiring, the patient
plate and its positioning before use.
• Only the surgeon wielding the active electrode
should activate the machine.
• Always replace the electrode in an insulated
quiver after use.
• If diathermy performance is poor, carefully
check the patient plate and lead rather than
increasing the dial settings.
Alarms. Monopolar diathermy depends on the
patient plate for its safety. If the plate is not connected to
the machine (plate continuity alarm), all diathermy
machines in use will alarm when switched on; only a few
possess an alarm system that ensures the plate is attached
to the patient. Rigidly adhere to the safe, correct proce-
dures: first connect the patient plate to the patient,
connect the return lead to the plate, switch on the
diathermy machine so the plate continuity alarm sounds.
Only now is the return lead connected to the diathermy
machine, thus silencing the continuity alarm. Never do
this in the reverse order. At the end of every operation
undo all these connections and switch off the diathermy
machine.
If the continuity alarm fails to silence, change the
patient plate and lead first, not the machine. Some
modern diathermy generators, such as the Eschmann and
Valleylab, possess systems that monitor the patient-plate
interface. These systems are explained in the user's
manual. Never disregard these alarms - check the patient
plate contact carefully.
The patient plate. The most common cause of acci-
dental diathermy burns is incorrect application of the
patient plate. It may not be applied at all, but more often
there is a failure to follow guidelines. Site the plate as
close as possible to the operation site, while ensuring that
diathermy current is moving away from ECG and other
monitoring electrodes. Make sure that the area under the
plate has a good blood supply to remove any heat gener-
ated. Avoid bony prominences and scar tissue. The whole
area of the plate must make good skin contact, so, shave
hairy skin and ensure the plate is not kinked or crinkled.
Do not allow skin preparation fluids to seep under the
plate.
The patient The second most common cause of
diathermy burns occurs when the patient touches earthed
metal objects such as drip stands, uninsulated 'screens'
and parts of the operating table. These small skin contacts
offer alternative return pathways for the diathermy
current, and the local current densities may be sufficient
to cause a burn.
If you have used an alcohol-based skin preparation, it
may pool, be ignited by the diathermy current and cause
a fire. As a rule avoid such skin preparations.
I I Key points
• Beware of using diathermy on or inside the
intestine - its gas contains hydrogen and
methane, both are inflammable and explosive.
• Beware of using diathermy on appendages
such as salpinx or penis, or isolated tissue such
as testis; high current density can persist
beyond the operative site.
• Remember that diathermy can damage other
structures, such as sutures and endotracheal
tubes and their balloons
If a burn occurs. Diathermy burns are often poorly
investigated and remain unexplained. Other skin lesions,
such as chemical burns from preparation solutions or
pressure sores, may masquerade as diathermy burns.
Definite electrothermal burns usually occur because of
lapses in procedure, rarely from faults in the diathermy
machine. The operating theatre record for all patients sub-
jected to diathermy should include the site of the patient
187
17 1
PREPARATIONS FOR SURGERY
plate; and when the plate and monitoring electrodes are
removed the underlying skin should be inspected. If a
possible burn is discovered, the patient and all attached
equipment should remain in the operating theatre while
you summon the electromedical safety officer. If the
alleged burn is discovered after the patient has left the
theatre, contact all those involved in the procedure and
determine the precise arrangement of equipment and
patient plate. All electrical equipment used should be
tested, including the patient plate lead.
Diathermy burns are usually full thickness and will
require excision. Inform the patient of the misadventure.
Diathermy and pacemakers. There are two poss-
ible dangers:
1 . The high frequency diathermy current may interact
with pacemaker logic circuits to alter pacemaker
function, resulting in serious arrhythmias, or even
cardiac arrest.
2. Diathermy close to the pacemaker box may result in
current travelling down the pacemaker wire, causing
a myocardial burn. The result will range from a rise
in pacemaker threshold to cardiac arrest.
For safe use of diathermy with pacemakers, contact a
cardiologist and ask about the type of pacemaker, why
and when it was inserted, whether it is functioning
properly, and what the patient's underlying rhythm is,
so you will know what will happen if the pacemaker
stops functioning.
bipolar diathermy to minimize spread of current and
sparking.
Key points
• Avoid diathermy completely if possible. If not,
consider bipolar diathermy.
• If monopolar diathermy must be used, place
the patient plate so that diathermy current
flows away from the pacemaker system.
• Use only short bursts, and stop all diathermy if
any arrhythmias occur.
Laparoscopic procedures. Sometimes the working
space can be 'crowded', and inadvertent contact may be
made between an instrument and the bowel, especially
if there is contact between the electrode and another
metal instrument, which is touching bowel. In a similar
way, current can pass along an organ, which is resting
against the gut, and pass out via the indifferent elec-
trode. An adequate view, carbon dioxide pneumoperi-
toneum, and use of well-insulated instruments should be
the aim. Apply careful technique by avoiding excessive
use of the diathermy, and 'tent' structures into space
before applying current. Use lower voltage currents or
Key point
Ensure that the insulation of instruments is
complete and undamaged, and avoid sparking
between bowel wall and electrode.
Lasers
The laser is a device for producing a highly directional
beam of coherent (monochromatic and in phase) electro-
magnetic radiation, which may or may not be visible,
over a wide range of power outputs.
Laser is an acronym for Light Amplification by the
Stimulated Emission of Radiation. This describes the prin-
ciple of operation of a laser. Energy is pumped into the
lasing medium to excite the atoms into a higher energy
state to achieve a population inversion in which most of
the atoms are in the excited state. A photon emitted as a
result of an electron spontaneously falling from the excited
to the ground state stimulates more photons to be emitted
and lasing action starts. After reflection back and forth
many times from a pair of mirrors at opposite ends of the
resonant optical cavity containing the lasing medium, the
number of photons is amplified, that is, the light intensity
or power is increased. One of the mirrors is only partially
reflecting and allows a small part of the laser light to
emerge as the laser beam. The lasing medium is com-
monly gaseous, such as argon or carbon dioxide, but may
be crystalline, such as neodymium, yttrium, aluminium
garnet (NdYAG). It is the lasing medium which deter-
mines the wavelength emitted. It is mainly the wavelength
of the laser which determines the degree of absorption in
tissue. However, surgical applications also depend on the
power density: the duration of exposure should be just
sufficient to produce the required effect. Delivery systems
are designed to allow the laser beam to be transported,
aimed and focused onto the treatment site. Argon and
NdYAG lasers, for example, are transmitted down fibre-
optic cables to a slit lamp or into an endoscope. Carbon
dioxide laser light is usually routed via a series of mirrors
through an 'articulated arm', and thereafter through a
micromanipulator attached to a microscope or colposcopy
Types
1 . Carbon dioxide infrared laser light has a wavelength
of 10.6 |mm. It is invisible and is rapidly absorbed by water
in tissue and has very little penetration. It is therefore
useful for vaporizing the surface of tissue, and water or
188
OPERATING THEATRES AND SPECIAL EQUIPMENT
17
wet drapes can be used as a safety barrier. There is a very
small margin of damaged tissue and healing is rapid,
with minimal scarring. Treatment is relatively pain free.
2. The NdYAG laser penetrates more deeply to
3-5 mm. The wavelength is 1 .06 u.m and is in the invisible
infrared light range. It is useful for coagulating larger tissue
volumes and leaves behind an eschar of damaged tissue.
Both the above types require a visible guiding beam
which is usually a red helium/neon beam.
3. Argon laser light is blue/green and hence absorbed
by red pigment. The principal wavelengths are 0.49 and
0.51 jjum. It is used principally in ophthalmology and
dermatology.
Clinical applications
Gastrointestinal tract. The NdYAG laser is fre-
quently used in the treatment of gastrointestinal pathol-
ogy. It can be employed for vaporizing and debulking
recurrent or untreated advanced oesophageal carcinoma.
Its use is predominantly in fairly short malignant stric-
tures and may be superior to intubation. However,
expanding covered metal stents may well prove to be a
better palliative alternative. Laser ablation is labour
intensive and requires treatments every 6-8 weeks. This
laser can be used for controlling gastrointestinal haemor-
rhage from the stomach, oesophagus and duodenum,
destruction of small ampullary tumours in the duodenum
and palliative resection of advanced rectal carcinomas. In
the future, photosensitization may prove to be of value.
The use of lasers in laparoscopic surgery is, perhaps, less
frequent at present. There is a risk of carbon dioxide gas
embolism.
Urology. The NdYAG laser can be used to treat low
grade, low stage transitional cell lesions in the bladder and
is suitable for treating outpatients under local anaesthetic.
Here again, photosensitizing agents such as haematopor-
phyrin (Hpd) may be used in conjunction with a laser light
wavelength of 630 nm. The beam is directed at sensitized
tissues which are then more easily destroyed.
Ophthalmology. The NdYAG laser can be used to
destroy an opaque posterior capsule during or following
extracapsular cataract extraction. The argon laser may be
employed for trabeculoplasty, to decrease intraocular
pressure in patients with open-angle glaucoma. Laser
photocoagulation is becoming standard treatment for
patients with various retinal diseases such as diabetic
retinopathy, and as a prophylactic measure in patients at
risk from retinal detachment. Most ophthalmic photo-
coagulators are argon lasers.
Otolaryngology. A carbon dioxide laser may be
used for haemostasis, removal of benign tumours and
premalignant conditions. The argon laser has been used
in middle ear surgery.
Vascular surgery. Laser angioplasty (carbon dioxide,
NdYAG and argon) has been used to vaporize atheroma-
tous plaques. Only approximately 50% of patients benefit,
and significant complications are reported, such as per-
foration of vessel wall.
Plastic surgery. Pulsed ruby lasers may be used to
remove tattoos, and port wine stains selectively absorb
the argon laser beam. The carbon dioxide laser may be
employed to resect atretic bony plates in congenital bony
choanal atresia.
Gynaecology. There are several uses in gynaecology.
Perhaps the most frequent is the treatment with a carbon
dioxide laser of cervical and vulval precancerous lesions
that have been identified by colposcopy.
Classification
Lasers are classified according to the degree of hazard:
Class 1 (low risk). These are of low power and are
safe. The maximum permissible exposure (MPE) cannot
be exceeded.
Class 2 (low risk). These are of low power, emitting
visible radiation. They have a maximum power level of
1 mW. Safety is normally afforded by natural aversion
responses, such as the blink reflex.
Class 3a (low risk). These emit visible radiation,
with an output of up to 5 mW, Eye protection is afforded
by natural aversion. There may be a hazard if the beam is
focused to a point, as through an optical system.
Class 3b (medium risk). These emit in any part of
the spectrum and have a maximum output of 0.5 W.
Direct viewing may be dangerous.
Class 4 (high risk). These are high power devices
with output in any part of the spectrum. A diffusely
reflected beam may be dangerous and there is also a
potential fire hazard.
Key point
Use high risk lasers with caution. Most medical
lasers are in this class.
Hazards
The manufacturers are required to classify and label the
product according to hazard level.
1. Patient hazard: inevitably, burning of normal tissue or
perforation of a hollow viscus may occur with
increasing depth of treatment (e.g. perforation of
189
PREPARATIONS FOR SURGERY
oesophagus) or damage to trachea or lungs during
ear, nose and throat (ENT) procedures.
2. Operator hazard: usually the operator is not exposed
to laser beams, but if you are accidentally exposed, it
is frequently your eyes or skin that are damaged.
Always wear eye protection since some laser beams
will penetrate, and be focused on, the retina. Corneal
burns or cataract formation have also occurred with
less penetrating beams.
Safety measures
1. There should be a laser protection advisor (LPA) to
consult on the use of the instruments throughout the
hospital and to draft local rules.
2. A laser safety officer (LSO) should be appointed
from the staff of the appropriate department using each
laser. This person may well be, for example, a senior nurse
and will have custody of the laser key.
3. Everybody using the laser should be adequately
trained in its use and be fully cognizant of all safety
precautions.
4. There should be a list of nominated users.
5. A laser controlled area (LCA) should be established
around the laser while it is in use, with control of
personnel allowed to enter that area. The entrance
should be marked with an appropriate warning sign,
usually incorporating a light that illuminates while the
laser is functioning.
6. While in the laser controlled area adequate eye pro-
tection, appropriate to the type of laser in use, must be
worn. The laser should not be fired until it is aimed at a
target, and usually there is an audible signal during laser
firing.
7. The laser should be labelled according to its classifi-
cation. Lasers in classes 3a, 3b and 4 should be fitted with
a key switch and the key should be kept by a specified
person. The panels which constitute the side of the laser
unit should have an interlocking device so that the laser
cannot be used if the panels are damaged.
There are various safety features that are required by
way of shutter devices and emergency shut-off switches.
Foot-operated pedals should be shrouded to prevent acci-
dental activation. Medical lasers require a visible low
power aiming beam, which may be an attenuated beam
of the main laser, if this is visible, or a separate class 1 or
2 laser, such as helium/ neon. The laser must be regularly
maintained and calibrated.
8. Environment: reflective surfaces should be avoided
in the laser controlled area. However, matt-black surfaces
are not necessary. Adequate ventilation must be provided
and should include an extraction system to vent the
fumes produced. These fumes are known as the Taser
plume'.
Key point
• Pay particular attention to avoiding fire. Class 4
lasers ignite dry drapes or swabs. Damp drapes
effectively stop carbon dioxide laser beams.
Fibre optics
Flexible instruments
Fibre optics have undoubtedly made an immense impact
on patient management. There is little evidence, however,
that the instruments that incorporate fibre optics neces-
sarily reduce mortality. Their value is in allowing accurate
diagnosis and assessment of, for example, upper gastro-
intestinal bleeding or oesophageal obstruction. Most
hollow viscera or tubes, even very narrow ones, may now
be inspected. Diagnostic and therapeutic procedures can
be performed under clear vision, such as exploration of a
ureter for tumour or stone, or subfascial ligation of incom-
petent perforating veins. Thin fibreoptic instruments are
integral to the development of minimal access surgery,
such as 5 mm telescopes used for retrieving bile duct
stones.
In the 1950s, Professor Harold Hopkins of Reading
University, UK, developed the earlier work of John Logie
Baird, the inventor of television, to further the design of
fibreoptic bundles, which could not only transmit a pow-
erful light beam but also, when suitably arranged, deliver
an accurate image to the viewer. In the 1960s, urological
instruments were developed incorporating multiple flex-
ible glass-fibre rods. Each fine fibre rod is constructed of
high quality optical glass and transmits the image, or
light beam, by the process of total internal reflection. This
principle allows light to travel around bends within the
fibre. Each fibre is only 8-10 |xm in diameter, and to
achieve the principle of total internal reflection it must be
coated with glass of low refractive index, to prevent light
dispersion. Many such coated fibres are bound together in
bundles which can bend. For light transmission, fibres
may be arranged in a haphazard manner (non-coherent).
For clear-image transmission, the fibres must be arranged
in a coaxial manner (coherent) (Fig. 17.3). The following
are examples of currently available flexible endoscopes
utilizing fibreoptic light bundles:
• Oblique (for endoscopic retrograde cholangiopancre-
atography (ERCP) and end-viewing gastroscopes
• Laryngoscope
• Bronchoscope
• Fibreoptic sigmoidoscope and colonoscope
• Cystoscope (pyeloscope)
• Choledochoscope
• Arterioscope.
190
OPERATING THEATRES AND SPECIAL EQUIPMENT
17
(a)
(b)
Fig. 17.3 (a) Non-coherent fibre bundles for light
transmission, (b) Coherent fibre bundles for viewing.
Reproduced from Ravenscroft & Swan (1984) by
permission of Chapman & Hall.
Each instrument has similar design principles incorpor-
ating the following:
• Coherent fibre bundles for high quality visual image
transmission
• Non-coherent fibreoptic bundles for light transmission
• A lens system at the tip and near the eyepiece of the
instrument
• A proximal control system to manoeuvre the tip of the
instrument and also to control suction and air/ water
flow
• Channels for blowing air or carbon dioxide and water
down the instrument, and for suction - the latter
doubles as a biopsy channel
• A wire guide incorporated to control tip movement,
which takes place in four directions, each usually
allowing a deformity of greater than 180° movement
• A cladding, consisting of a flexible, jointed construc-
tion, covered by a tough outer vinyl sheath.
Figures 17.4 and 17.5 show the basic structure of a typical
endoscope, and Figure 17.6 shows the tip of an instru-
ment, illustrating the lenses for light transmission and
viewing, a suction channel, which should be large so it
can be used in the presence of gastrointestinal haemor-
rhage, and a small nipple directed over the lens, to enable
the wash solution to clear the lens of debris.
Light sources should emit a powerful beam and the
intensity is usually 150 W. Many light sources employ a
halogen bulb, which needs to be fan cooled.
Rigid endoscopes
Optical systems in rigid endoscopes also employ the prin-
ciple of total internal reflection, but there are several lens
systems in addition. The objective lens systems are nearest
the image, and the relay lens systems are nearer the eye-
piece of the rigid instrument, through which the observer
Eye -piece
External tight
source
Image guide
(coherent bundle)
Light guide
(non-coherent
bundle)
Distal lip
Fig. 17.4 Basic design of a fibreoptic endoscope.
Reproduced from Ravenscroft & Swan (1984) by
permission of Chapman & Hall.
U
M
Fig. 17.5 Further details of the basic design of a
fibreoptic endoscope. A, endoscopic 'umbilicus'; B, suction
pump; C, air pump; D, water reservoir; E, endoscopic
insertion tube; F, biopsy port; G, suction button; H,
air/wash button; I, endoscope control head; J, combined
suction biopsy channel; K, water channel; L, air channel;
M, combined air/water port. Reproduced from Ravenscroft
& Swan (1984) by permission of Chapman & Hall.
191
17 %
PREPARATIONS FOR SURGERY
B
forcible distortion, dropping and, particularly, of crushing
from biting by patients' teeth; always insert the peroral
endoscope through a suitable mouth gag. Broken fibres
appear as black dots when viewed through the instrument.
Fig. 17.6 The top of an end-viewing fibreoptic
instrument. A, forceps raiser; B, wash jet; C, image
guide; D, light guide; E, biopsy/suction channel.
Reproduced from Ravenscroft & Swan (1984) by
permission of Chapman & Hall.
views a rectified and magnified image. Light is transmit-
ted through a cable of non-coherent fibres or liquid elec-
trolyte solution. Vision is through coaxial fibres which
direct the light coaxially through a lens system in the rigid
tube. Some of the longer lenses are made of high quality
optical glass and act as a single large optical fibre for
image transmission. Examples of rigid instruments are:
• Cystoscope, urethroscope, pyeloscope, urethroscope
• Choledochoscope
• Laparoscopes.
The lenses at the far end of the instruments vary to allow
different fields of view and minimize peripheral field
distortion.
Care of fibreoptic instruments
1. They must be properly cleaned and disinfected
before use. Debris may block channels and make suction
and insufflation of air and liquid difficult. After use, the
instruments should be cleaned internally by utilizing one
of several automatic cleansing machines, and externally
with a suitable detergent solution. 'Q-tips' may be
employed to clean lenses. Instruments should be soaked
for at least 5-10 min between patients, often in a 2%
gluteraldehyde solution, although 70% alcohol and low
molecular weight povidone-iodine are alternatives.
2. In order to avoid instrument damage, endoscopies
are usually performed in dedicated units under expert
care. Damage is more likely to occur when a variety of
people handle and clean instruments. Guard against
Key point
Ensure that only competent and careful people
use and care for these expensive and valuable
instruments.
Autologous cell salvage
With recent anxieties over transmitted disease, expense,
religious views and the occasional scarcity of blood, autol-
ogous (blood derived from the same individual) blood
transfusion may be used. The advantages are consider-
able: it avoids blood-related disease transmission, trans-
fusion reactions, immnunosuppression and the need for
grouping. A rapidly obtainable supply is available. The
blood is collected via a sucker from the wound site, anti-
coagulated, filtered and then passed through a washing
phase, using saline. Washing removes all but the red cells,
which are concentrated to an acceptable haematocrit and
then reinfused. This technique is of particular use in car-
diothoracic, vascular and orthopaedic surgery, especially
when the loss of blood is expected to exceed 1 litre. It is a
safe procedure provided you follow the rules. As a rule,
do not use blood contaminated with septic fluids and
malignant cells. Never use blood contaminated with bile,
gut contents, meconium, urine or amniotic fluid. Cell
salvage cannot be used if the blood is likely to mix with
fluids which would lyse red cells, such as water, hydrogen
peroxide, alcohol, povidone-iodine antiseptic, fibrin glue
or antibiotics that are unsuitable for parenteral use.
The alternative is predonation.
Cryosurgery (syn. cryotherapy or
cryocautery)
Any application of an instrument that touches tissue at an
extreme of temperature produces cell death. Cryosurgery
(Greek kryos - frost) is the freezing of tissue to destruc-
tion. Although cells are destroyed at -20°C, they may
recover at higher temperatures than this. After freezing,
the destroyed tissue sloughs off and reveals a clean, granu-
lating base. The treatment is relatively pain free and
minimizes blood loss. The object is to destroy abnormal
tissue and preserve adjacent, healthy areas. You achieve
this by producing an ice ball at the tip of a cryoprobe
(Fig. 17.7). You must watch the size of the resulting ice
ball, to control the volume of tissue destroyed. The size of
192
OPERATING THEATRES AND SPECIAL EQUIPMENT
17
Fig. 17.7 An ice ball at the tip of a cryoprobe.
Reproduced by permission of Eugene A. Felmar, Santa
Monica Hospital Medical Center, USA.
the lesion produced by cryosurgery is related to the tem-
perature at the tip of the ice probe, the size of the tip and
the number of freeze-thaw sequences. The size of the
iceball increases until the heat loss at the edge of the
iceball is too small to permit further freezing of adjacent
tissues. The size of an iceball and the extent of destruction
can then be increased by a further freezing sequence. As
a rule, allow the iceball to spread 2-3 mm into healthy
tissue to ensure adequate destruction of the diseased area.
Inevitably freezing a wart on the sole of the foot is less
Fig. 17.8 Cross-section of a cryoprobe tip, illustrating
the Joule-Thompson principle. Reproduced by
permission of Eugene A. Felmar, Santa Monica Hospital
Medical Center, USA.
critical than reattaching a retina. Various probe tips are
available for the different tasks demanded of cryosurgery.
Principles of therapy
According to the Joule-Thompson principle, when gas
expands, heat is absorbed from the surrounding matter.
The simplest example of this is spraying ethyl chloride
vapour on skin, which, as it releases gas, subsequently
freezes. With a cryoprobe, however, the liquid gas,
usually nitrogen or carbon dioxide, is sprayed against the
inside of a hollow metal probe. The gas then expands in
the tip and freezes the tissue on contact (Fig. 17.8).
Cell injury with cryotherapy
1 . Immediate phase: ice crystals form in the cell,
rupturing the cell membrane. This is most effective
with rapid freezing at greater than 5°C s^ 1 .
2. Intracellular dehydration: results in increased and toxic
levels of intracellular electrolytes.
3. Protein denaturation: occurs in the lipoprotein
structure of the cell membrane, nucleus and
mitochondria.
4. Cellular hypermetabolism; results in enzyme inhibition.
Later in the course of injury there is also a loss of blood
supply, causing tissue necrosis, and the resultant slough,
before separation, protects the tissues deep to the injury.
When the slough separates it leaves a clean ulcer.
As nerve endings are susceptible to cold injury, painful
lesions can be rendered insensitive. Also, the treatment is
not particularly painful for the patient, and local analgesia
is usually unnecessary. Adjacent neurovascular structures
are relatively safe, as collagen and elastic tissue resist freez-
ing. Thus, the advantages of cryotherapy are that it is a rela-
tively pain-free and simple method of destroying tissue,
usually leaving clean wounds, often with a reasonable scar.
The disadvantages of the technique are that frozen
tissue cannot be analysed histologically, and thus this
method of treatment is unsuitable for any lesion for which
you will require microscopic examination. It may some-
times be difficult to gauge the exact penetration in the
depth of the tissues treated. Thus, its use may be limited
in curative treatment of malignancy, and is of value in pal-
liation. Occasionally there is some bleeding, and later dis-
charge after the slough separates following, for example,
cryosurgical treatment of haemorrhoids.
Clinical applications
Since there are various shapes of probe tips, a reasonable
variety of therapeutic applications is available. To
ensure that freezing occurs, there must be a wet contact
193
17
PREPARATIONS FOR SURGERY
to allow thermal conductivity. Two or three freeze-thaw
cycles may be applied with overlap of the treated areas
if necessary.
Examples of the clinical application of cryosurgery
include the following:
• Proctology: haemorrhoids and warts
• Gynaecology: cervical erosions and warts
• Dermatology: warts, low grade skin cancers, herpetic
lesions
• ENT: pharyngeal tonsillar remnants, carcinoma of the
trachea, hypophysectomy
• Ophthalmology: cataract extraction, glaucoma,
detached retina
• Neurosurgery: Parkinson's disease and cerebral
tumours.
Microwave ablative techniques
You can use this technique on prostatic tissue, for benign
prostatic hypertrophy, and the endometrium - usually for
menorrhagia. The principle of treatment depends on the
transfer of energy by the use of microwaves, which are a
form of electromagnetic energy. Penetration depths depend
on the electrical properties of the tissues, and the frequency
of the electromagnetic wave. Conventional microwave
kitchen ovens use energy at a frequency of around
2.45 GHz, which, in tissue with a high water content,
would penetrate to a depth of approximately 18 mm. The
microwave applicator has a strength of 9.2 GHz, uses 30 W
of power and the treatment takes about 2-4 min. For
endometrial ablation performed under general or regional
anaesthesia, the cervix is dilated, the length of the uterine
cavity is measured, and the calibrated and non-adherent
probe is inserted to the fundus and withdrawn with
side-to-side movements. Temperature measurement is
monitored and probe temperatures of 80-95°C are reached
to ablate the endometrium to a depth of 4-6 mm.
Interestingly, with this range of endoluminal temperature,
there is little serosal heating.
This treatment may be safer than endometrial resection
and hysterectomy, as there are fewer complications. The
few serious complications of the procedure have been
endometritis, cervical splitting during dilatation, and in one
instance perforation of a retroverted uterus. There are other
methods of endometrial ablation. This is merely used as an
example of microwave energy, and you should not confuse
it with radiofrequency endometrial ablation (RAFEA).
Ultrasound
Diagnostic
Ultrasound probes provide a valuable aid during abdomi-
nal surgery to identify tumour deposits and anatomical
landmarks such as blood vessels. Clear guidance may be
obtained as to the resectability of tumours or the presence
of clinically undetected metastatic deposits. Hand-held
ultrasound probes can be employed at open operations;
for example, small islet cell tumours of the pancreas may
be located accurately.
Small laparoscopically inserted instruments are also
used for staging and anatomical purposes when per-
forming operations with minimal access (see Ch. 23).
They compensate to some extent for the inability to
palpate structures. During laparoscopic cholecystectomy,
a probe may be used not only to identify structures but
also to locate common bile duct stones.
Surgical aspirator
There are various ways in which the liver parenchyma
may be dissected with minimal blood loss. One of these
is the CUSA (Cavitron UltraSonic Aspirator). The oper-
ating titanium tip of the instrument vibrates longitudi-
nally at 23 000 oscillations per second (23 kHz). The
instrument works by converting electromagnetic energy
to mechanical movements. An electrical coil wrapped
around metal laminations sets up a magnetic field, thus
causing the metal to vibrate. The fine hollow tip of the
instrument disrupts solid parenchyma by its fine vibra-
tions and the heat this generates. When debris is shed, it
is mixed with fluid jetting from the instrument and the
mixture is sucked away. More solid and fibrous struc-
tures, such as ducts and blood vessels, are not disrupted,
and may then be clipped with haemostats or ligated. Not
only may this instrument be useful for open, solid
parenchymal dissection, but it may also be used during
laparoscopic dissection of the gallbladder or mobiliz-
ation of the colon.
Ultrasonic harmonic scalpel
Increasing use of this instrument attests to its ability to aid
safe, careful dissection with less bleeding than accompa-
nies diathermy dissection. The instrument works by
transforming electrical energy from a generator into
mechanical energy through a set of piezoelectric ceramics,
which are contained in a hand piece. The mechanical
energy is passed through a disposable element, often a
hook or clip, which vibrates at approximately 55.5 kHz.
The energy spreads a small distance around the instru-
ment tip. The extreme vibrations fracture internal cellular
bonds. Proteins are denatured and reorganize to form a
sticky coagulum. Vessels up to 2 mm in diameter can be
safely divided. Soft tissue coagulation occurs at tempera-
tures below 100 S C, producing minimal charring and
smoke or vapour.
194
OPERATING THEATRES AND SPECIAL EQUIPMENT
17
A real advantage of this equipment is that it reduces the
number of instrument changes during an operation, such
as haemostats, staples, scissors and ligatures. It is a mul-
tifunctional instrument facilitating precise cutting with
minimal lateral thermal damage. It does not use electric-
ity, with all its potential risks. It was introduced in the
mid-1990s and is used in, for example, the specialities of
gastrointestinal surgery, gynaecology, urology and oto-
laryngology. Do not use it for incising bone or for contra-
ceptive tubal ligation.
The harmonic scalpel system is valuable for soft tissue
incisions where you require good haemostasis and
minimal thermal injury. The instrument can be used for
open or laparoscopic surgery as an adjunct to, or substitute
for, diathermy, lasers or steel scalpels.
Argon beam (plasma) coagulator (Valleylab)
This instrument offers a thermal technique for sealing
blood vessels from large, raw areas such as the cut surface
of the liver and kidney. It works by passing an electrical
current through what is called a "plasma arc', created in
argon, not air. When electrons are fired into the gas, ion-
ization occurs, which in turn produces further electrons.
These then ionize more gas and a "domino" effect takes
place. The plasma thus consists of free electrons, positive
ions and neutral atoms (Fig. 17.9).
The coagulator can be valuable in controlling bleeding
resulting from coagulation disorders. It applies a direct,
high frequency electric current to the target tissue without
direct contact. The effect is well defined and has a self-
limiting depth of penetration. There is minimal charring
of the treated tissues, producing a thin and flexible eschar.
As a result there is a minimal tendency for rebleeding.
Because there is no contact between the instrument and
the coagulated area, the coagulum is not pulled off and so
is unlikely to rebleed. The tissue which has been treated
by this technique develops a spongy appearance and
enlarges the tissue surface.
X-rays
Preoperative findings
Key point
• It is negligent and dangerous to start an
operation without having available all the
radiological results and films (see Ch. 4).
Place essential films, with the names, date and hospital
number checked, correctly orientated, on the screen so
you can refer to them as necessary.
Gas no22ie
Electrode—
Argon gas arc
Tissue target
Fig. 17.9 Argon-enhanced coagulation. This is in effect
a bipolar diathermy with the pathway from the active
electrode to the tissue completed through argon gas. An
arc or beam is produced with argon gas from the
nozzle, which makes contact with the target tissue.
Electrons are fired into it from the electrode, producing
ionization, which, in turn, produces further electrons;
these produce more ionization and so generate a
domino or self -generating effect. The plasma arc is thus
partly converted into positive ions and free electrons -
in effect passing a current without instrument contact.
The conventional active diathermy electrode adheres to
the coagulum and may pull it off as it is withdrawn. The
argon beam carrier overcomes this disadvantage, as
there is no physical contact with the tissue coagulum.
Capital letters indicate argon gas; capital letters such as
+A+ indicate ionized argon, o- indicates electrons. It
overcomes the disadvantage of adherence of the active
diathermy electrode to the tissue coagulum.
Intraoperative procedures
Diagnostic help. An example is on-table cholan-
giography. Use sufficiently dilute contrast medium to
allow one to 'see through' the common bile duct on the
film. Fill the biliary tree adequately to show the main
intrahepatic ducts as well as the common bile duct.
Contrast medium is heavier than bile and tends to gravi-
tate to dependent ducts. If the ampulla is patent, contrast
medium flows into the duodenum, which is clearly recog-
nizable by its mucosal pattern. Remember to put a 20°
195
PREPARATIONS FOR SURGERY
lateral tilt on the table to eliminate the overlap of contrast
on the vertebral column.
Intraoperative angiography can be performed follow-
ing a steady intra-arterial injection, and provides ade-
quate films. Adverse reactions to modern contrast media
when the patient is generally anaesthetized are very rare.
Therapeutic use. Imaging using fluoroscopy may facil-
itate therapeutic procedures. It is valuable for simple pro-
cedures, including fracture reduction. Complex techniques
include interventional uroradiology. Many of these tech-
niques can be performed either in the operating room or in
the X-ray department; facilities for fluoroscopy are usually
better in the X-ray department, but asepsis is better in the
operating theatre. X-ray machines are difficult to clean and
are potential sources of crossinfection. In specialist centres,
dedicated complex X-ray rooms may be organized in a
fashion similar to operating theatres, or the facilities for
radiology may match those in the X-ray department.
Key points
• Discuss problems beforehand with a radiologist
and subsequently report the outcome and
anatomical findings.
• Give adequate warning to the radiographer of
the need for X-rays in the operating theatre.
Equipment
This is more likely to be mobile than static. The use of
image intensification avoids the need for you to allow
your eyes to become dark-adapted. Mobile image inten-
sifiers for use in the operating theatre are mounted on a
small C-arm. The table top must be radiolucent, with
space beneath as well as over the table for the X-ray tube
and the image intensiner. If films alone are required, the
table top must have a 'tunnel' that admits the X-ray cas-
sette beneath the patient. Alternatively, the cassette may
be draped in sterile towels. This may be necessary, for
example, if you need to carry out intraoperative mesen-
teric angiography on bowel lifted out of the abdomen at
laparotomy. For a small field, the X-ray cassette can be
placed on the image intensifier itself to obtain a film.
Some modern machines can produce dry silver images
directly from the television monitor.
Biplane screening is not usually available in the oper-
ating theatre. The mobile C-arm is, nevertheless, quite
versatile and the effect of 'parallax' can be used to aid the
judgement of depth.
Mobile X-ray sets operate from designated 13 A sockets
that are on a separate ring main from other essential
equipment. Modern mobile sets use 'sparkless' switching
to avoid the danger of igniting inflammable gases. It is
desirable to keep the mobile X-ray machine in the
operating suite.
X-rays and the law
X-rays, as well as scalpels, become weapons of assault if
not used with care. Medical staff clinically directing
examinations employing ionizing radiation are required
to have obtained a certificate demonstrating that they
have received some training in radiation protection. This
should eventually be included in the undergraduate cur-
riculum. Equipment must be regularly serviced and cali-
brated, and 'local rules' applied. In case of doubt, contact
the hospital radiation protection supervisor.
Key points
• Only radiologists, radiographers or others
holding an approved qualification may direct
exposures.
• Look after yourself, other staff in the theatre
and the patient. Use the lead aprons.
Safety
• Remember that the patient 'scatters' the X-ray beam.
The inverse square law applies, so staff should not be
unnecessarily close. Be aware of the screening time and
record it.
• Do not X-ray the abdomen of pregnant patients unless
absolutely necessary. Establish the date of the last
menstrual period before the patient is anaesthetized.
Key point
• Take an interest in imaging, as 'a picture is
worth a thousand words'.
Microscopes
Spectacles have been available for nearly 700 years and
the compound microscope for about 300 years, but it was
only 70 years ago that a microscope was used in theatre,
and only 30 years ago that its use became more
widespread. Although they were introduced very gradu-
ally to the operating theatre, they have now become indis-
pensable in a wide variety of surgical fields. They offer
improved views of the surgical field, more precision,
greater flexibility, and less trauma to delicate tissues. They
provide good stereoscopic appreciation of depth, through
a narrow surgical approach, much smaller than your own
unaided interpupillary distance allows.
196
OPERATING THEATRES AND SPECIAL EQUIPMENT
17
A Swedish otolaryngologist, Nylen, introduced his
monocular microscope in the surgical treatment of
otosclerosis in 1921. A year later his chief, Professor
Holmgren, used a binocular microscope for the same
condition. In 1925, Hinselman used a microscope for
colposcopy, but aside from this for three decades
otolaryngologists alone continued to use microscopes. In
Chicago, Perritt used a microscope for ophthalmic
surgery in 1950, and Zeiss started to mass produce their
Mil surgical microscope in 1953. Clinical applications
then expanded: Jacobson in vascular surgery in 1960;
Kurle in neurosurgery and Burke in plastic surgery in
1962. With the increased employment of free transfer flaps
and microvascular anastomosis, the use of the operating
microscope reaches several surgical disciplines.
Features of an operating microscope
• Eyepieces provide an adjustment for interpupillary dis-
tance and each eyepiece has a range of 5 dioptres.
• Binocular tube may be straight or inclined.
• Beam splitter allows for the connection of extra viewing
tubes for observation and assistance. It also makes the
use of still and video cameras possible as teaching aids.
• Magnification system. Magnification is available as a
galilean system, variable in steps (e.g. x6, xlO, x25, x40),
or as a zoom system.
• Objective lens allows the working distance to be altered
by changing lenses with variable focal lengths. For
example:
for ophthalmology and plastic surgery
for otology and vascular surgery
for gynaecological tubal surgery
for neurosurgery
for laryngoscopy.
Depth of field. The stereoscopic depth of field is less at
higher magnification. Focus at higher magnification
first, then reduce to the working magnification so as to
have the best focus at the centre of the depth of field.
Light . A powerful coaxial halogen light is incorporated
in the body of the microscope. Oblique light is available
for eye surgery.
Instruments used with microscopes
Each speciality has developed microsurgical instruments
for its own needs; however, the following basic instru-
ments are common to many specialities:
* Spring-handled needle holder such as Borraquer or
Castrovieso, ophthalmic.
• Spring-handled microscissors, straight or curved. The
straight are for cutting vessels and the curved for
cutting tissue and thread.
/= 150, 175, 200
/=250
/ = 250 or 300
/ = 300 or 400
/=400
• Jezvellers' or watchmakers' forceps in a wide variety
• Microsurgical clips such as Scoville— Lewis, or fine
Heifetzs neurosurgical clips, can be used for vessel
anastomosis.
• Microelectrode: monopolar or bipolar cautery is
necessary.
• Suture material: (1) blood vessel anastomosis: 9/0 or
10/0 nylon on a 3-6 mm needle with a tapered end;
(2) nerve anastamosis: as above, but the needle has a
cutting point; (3) fallopian tube work: 7/0 or 8/0
absorbable non-reactive suture with a 4 mm or 6 mm
reverse cutting needle.
• Sterilization: sterile rubber cups or drapes are available
to cover the controls.
• Adjustment: versatility in position demands several
interlocking arms and counterbalanced vertical move-
ment, as well as a geared angled coupling between the
microscope carriage arm and body. This enables you to
swing the microscope from side to side while mounted
in an oblique axis.
• Mounting: can be on a solid, well-balanced mobile
floor stand, or a fixed ceiling mounting. Wall-mounted
microscopes are also available.
Control of tremor
Counteracting surgical tremor is of vital importance. The
instrument or the limb on which it is held must be firmly
supported as close to the point of work as possible.
The future
The combination of the laser with a micromanipulator to
the objective lens of the microscope will enhance the use
of both instruments in the future.
Summary
• Are you familiar with the requirements of
behaviour and technique to obviate
operating room infection?
• Have you learned the methods of
positioning and moving unconscious
patients to avoid injuring them?
• Do you accept that you are in charge of
the tourniquet, diathermy, laser, cryoprobe
and X-rays in theatre?
• Will you lead by example in the operating
room, by adopting careful and responsible
attitudes to delicate and potentially
dangerous equipment?
197
PREPARATIONS FOR SURGERY
ACKNgwyyg^
I am deeply grateful for help with writing this chapter to:
Mr John Bancroft for the diathermy section; Dr David
Parker for the section on X-rays in theatre; Mr Derry
Coakley for the section on microscopes; and to my wife
for her help in the section on lasers. I should also like to
thank Miss Sharon Langford for typing the manuscript. I
am grateful to Ethicon Endosurgery (a Johnson & Johnson
Company) for information on the Harmonic Scalpel
System; to the Microsulis Group for data on their
Microwave Endometrial Ablation System; to Frigenis for
help with the Autologous Transfusion Cell Salvage
System; and to Valley lab for guidance on the use of the
argon beam coagulator.
Further reading
Brigden RJ 1988 Operating theatre technique, 5th edn. Churchill
Livingstone, Edinburgh
Douglas DM (ed.) 1972 Surgical departments in hospitals: the
surgeon's view. Butterworth, London
Johnston IDA, Hunter AR (eds) 1984 The design and utilization
of operating theatres. Edward Arnold, London
Cell salvage
Duguid JKM 1999 Review. Autologous blood transfusion.
Clinical and Laboratory Haematology 21: 371-376
Diathermy
Dobbie AK 1974 Accidental lesions in the operating theatre.
NAT News December
Earnshaw JJ, Keene TK 1989 Gastric explosion: a cautionary
tale. BMJ 293: 93-94
Editorial 1979 Surgical diathermy is still not foolproof. BMJ
12: 755-758
Pearce J A 1986 Electros urgery. Chapman & Hall, London
Fibre optics
Ravenscroft MM, Swan CMJ 1984 Gastrointestinal endoscopy
and related procedures - a handbook for nurses and
assistants. Chapman & Hall, London
Lasers
1982 General guidance on lasers in hospitals. Medical physics
and bioengineering working group. Welsh Scientific Advisory
Committee (WSAC)
1983 Guidance on the safe use of lasers in medical practice.
HMSO, London
Murray A, Mitchell DC, Wood RFM 1992 Lasers in surgery - a
review. British Journal of Surgery 79: 21-26
Microscopes
Taylor S 1977 Microscopy. Recent advances in surgery. Churchill
Livingstone, Edinburgh, ch. 8
X-rays
Ionizing radiation regulations 1985, 1988
Mound RF 1985/1988 Radiation protection in hospitals
(Medical Sciences Series). Adam Hilger, Bristol
198
Adjuncts to surgery
A L G. Peel
Objectives
Recognize the importance of good theatre
management.
Ensure basic understanding of usage and
care of theatre instruments, accessories
and special equipment.
Appreciate the place of implants and tissue
glues in modern surgical practice.
INTRODUCT^
In health service economics an operating suite requires
large capital and revenue budgets and this is favourably
influenced by careful management of utilities. Good
care of quality instruments ensures their long use;
appropriate ordering and stocking means the shelf-life
of equipment is not exceeded; wastage due to change in
practice is reduced to a minimum; and storage space is
efficiently used. The avoidance of an unnecessarily wide
range of equipment and materials allows better use of
capital.
From the medicolegal aspect, the establishment of
simple protocols aids efficient management within the
theatre complex and helps to reduce errors, such as break-
downs in sterility or retention of swabs or instruments in
patients.
A practical example of the rapidly changing scene in
surgical practice is illustrated by orthopaedic surgery,
where considerable expansion has occurred, particularly
in prosthetic joint replacement, and in this field infection
can result in very costly failure in terms of patient
morbidity and financial implications to the health
service.
In the attempt to 'abolish' infection to elective
orthopaedic surgery the following factors are considered
important.
Patient screening for occult infection
Give particular attention to:
• Possible urinary tract infection in females
• Carrier status - postpone elective surgery until
pathogens are eliminated, for example nasal
Staphylococcus aureus.
THEATRE MANAGEMENT
1. Orthopaedic theatre should be dedicated to 'clean'
orthopaedics, where no dirty or contaminated orthopaedic
operations and no general surgery is carried out.
2. Clean air enclosures. The routine use of clean air
enclosures has reduced the infection rate in prosthetic
joint surgery of hip and knee by more than half compared
with conventionally ventilated theatres. Unidirectional
air systems, especially with a downflow direction,
reduces bacteria-carrying particles from 400-500 nrf 3 to
30-40 m" 3 . Power tools produce additional problems
because they create an aerosol spray, which effectively
disseminates bacteria and viral particles.
3. Theatre gowns. Airborne bacterial dispersion can be
further reduced by the use of appropriate fabric clothing.
It is not widely appreciated that, in either conventional or
unidirectional airflow theatres, the use of disposable fabric
gowns alone in lieu of cotton gowns has not achieved a
significant reduction in bacteria-carrying particles.
Drawbacks to conventional clothing
Bacteria from you, the surgeon, tend to be
pumped by air through or out of cotton
pyjamas and gowns into theatre air.
Bacteria from you are drawn through wet
clothing by capillary action, contaminating the
sterile operative area.
Contamination of you with patient's fluids.
199
18
PREPARATIONS FOR SURGERY
Alternative clothing
It has been stated that pharmaceutical manufacturing
areas would be closed down if they used clothing cur-
rently worn in the majority of operating rooms. The
choice includes:
• The total exhaust gown, developed by the outstanding
orthopaedic surgeon Sir John Charnley, which is well
established for clean orthopaedic surgery.
• Disposable non-woven clothing such as Sonta (manu-
factured by DuPont Ltd), which has been shown to be
effective.
• Breathable plastic membrane clothing which requires
seals at the neck and trouser openings, with the result
that the wearer soon becomes hot and uncomfortable.
• Close woven polyester or polycotton fabrics which are
expensive but represent a significant improvement
over conventional garments. The cost must be
equated with the significant costs of morbidity from
infection.
Theatre technique
1 . Make sure you 'scrub up' in the prescribed manner.
Protect your skin 'envelope'; gently scrub your nails
but wash the remainder of skin with a suitable agent
such as 20% chlorhexidine gluconate solution (e.g.
Hibiscrub) or 10% aqueous povidone-iodine
solution (e.g. Betadine) starting from fingertips,
washing proximally avoiding subsequent
contamination.
2. Use closed gloving technique.
3. Double glove when carrying out orthopaedic implant
procedures or when using power tools.
wm*>
Key points
• If your gloves become contaminated or pierced,
change them.
• At the conclusion of the operation check your
gloves carefully before removing them. You
may have sustained an unnoticed needlestick
injury.
DMSSII^
Make sure you appreciate why you are applying dress-
ings, what you expect from them and how often they
should be changed.
1. If you have closed the wound and it is sealed and
dry, a dressing may be unnecessary or be merely collo-
dion, modern plastic spray or adherent plastic strip.
2. For acute open wounds that are not contaminated
the best dressing is closure by suture, flaps, grafts
or temporary synthetic non-adherent non-allergenic
dressings.
3. Open wounds that are producing exudate require
absorbent dressings. If these become soaked through to
the surface, bacteria may penetrate through from the
surface. Consequently, ensure that the absorbent dress-
ings are changed regularly. Tulle (net - named after
the French town near Limoges) of paraffin gauze or
plastic, sometimes containing a bacteriocidal, such as
chlorhexidine or povidone-iodine, may be applied to
allow exudate to pass through it. The exudate can be
absorbed into dressings placed on the tulle. Some starch-
containing hydrogel dressings also absorb exudate.
Hydrocolloid seals the wound, provides a moist
environment and can be left for up to 1 week. Bead
dressings also absorb exudate. Plastic foam can be cut
from a sheet or poured in to set, creating a shaped filling
for a defect.
4. Infected wounds need bacteriological assessment,
careful debridement of all dead tissue, and in some cases
the application of appropriate substances or dressings.
Eusol (Edinbugh University solution of lime) was for-
merly popular but is now discouraged as damaging to
tissues. Normal saline dressings, sodium hypochlorite
solutions and hydrogen peroxide solutions may be
applied.
5. For the treatment of slow-healing wounds, topical
negative pressure has been tried over an open cell foam
dressing or saline-moistened dressing. A negative pres-
sure of 125 mmHg can be exerted continuously for 48 h
and then intermittently.
6. A wide range of materials and substances is now
available for managing chronic wounds. Of course, you
must first exclude an underlying cause and ensure that
the blood supply and oxygenation are satisfactory. Apart
from skin grafts or flaps, biological techniques in use
include:
a. Growth factors
b. Hyperbaric oxygen
c. Allograft skin - prepared from porcine skin
d. Amniotic membrane, which is thought to entrap
inflammatory cells
e. Chitosan - prepared from the chitin of organisms
with an exoskeleton, used as an occlusive dressing
f. TransCyte - human newborn fibroblasts cultured on
nylon mesh
g. Procuren - prepared from the patient's own blood
platelets to stimulate wound healing.
200
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ADJUNCTS TO SURGERY
18
INSTRUMENTS
Surgeons and instrument makers have combined to
produce a wide range of instruments. Some, such as
certain scissor forceps and retractors, may be used in
several different fields of surgery. Others have more spe-
cific functions, for example, those used in anal surgery,
such as Park's anal retractor and Lockhart-Mummery
fistula probes. Consider what your requirements are for
instruments and appreciate the range and potential of dif-
ferent instruments. One advantage of a training rotation
scheme is that it allows you to experience a number of
surgical disciplines and permits you to observe instru-
ments being used in a variety of procedures. You can then
reapply this knowledge to particular problems in what-
ever field you subsequently work.
Instruments are a sound investment; whenever possible
use those of the highest quality. Of equal importance is the
investment in maintenance care, mechanical and chemical
cleansing, particularly of hinge joints, adjustment of mis-
alignment and regular sharpening of cutting instruments.
Although you cannot control the maintenance, you do
have a responsibility to avoid damage to the instruments
by not dropping them or using them inappropriately
Sterilization
The majority of instruments are autoclaved (moist heat
under pressure for a prescribed time) and this process
needs constant monitoring, with care in the packing of the
autoclave and verification that the temperature, pressure
and time are correct.
Where steam autoclaving is impracticable and may
cause damage, alternatives include (see Ch. 19):
• Formaldehyde autoclave.
• Ethylene oxide.
• Gluteraldehyde 2% solution with prolonged immer-
sion. It is rendered ineffective by organic debris. The
substance is toxic and causes skin irritation so the pro-
cedure must be carried out in a well-ventilated room.
Alternatives are being developed.
• 7-Irradiation, widely used for the commercial steriliza-
tion of plastic instruments.
Instrument sets
It is advantageous to have the instruments required for a
particular surgical procedure packed and sterilized in a
single set. As far as possible, each type of instrument
should be included in multiples of five. Each design or
size of artery forceps is grouped in separate fives or tens,
scissors of differing size and design are grouped in fives.
A standardized typed, numbered, contents list is included
in the sterilized set for each operation. This reduces the
number of single-packed instruments that need to be
opened and, more importantly, simplifies the instrument
count at the beginning and end of each procedure.
Develop a close liaison with the central sterile supply
department (CSSD) and theatre management to ensure
adequate supplies of trays to meet the demands of a full
schedule of operating lists. The organization is put
particularly under strain when carrying out many minor
procedures with a quick turnover.
LIGATURES, SUTURES, STAPLES AND
CLIPS_ „_____„ „„„,__,__.„„.„.._,„
When selecting a ligature or suture, consider several
factors with regard to the material itself.
1 . Is the material to be absorbed? Catgut has been with-
drawn because of fears that it may contain prions (coined
from 'protein')/ which are inheritable or mutant, transmit-
table 'rogue' proteins associated with, in particular, bovine
spongiform encephalopathy (BSE) and scrapie in sheep.
New synthetic materials are absorbed more reliably than
formerly, so the strength remains long enough for healing
to be well advanced before a suture is absorbed. In some sit-
uations, absorbable sutures have replaced non-absorbable
threads; for example, abdominal wounds are often closed
using reliable, slowly absorbed, synthetic sutures. The syn-
thetic threads may be monofilamentous, such as polydiox-
anane (PDS), polyglyconate (Maxon) and glycomer 631
(Biosin), or multifilamentous, such as polyglactin (Vicryl),
poly gly colic acid (Dexon) and lactomer 9-1 (Polysorb).
2. Non-absorbable natural threads, such as silk and
linen, are still used. Polyesters, polypropylene and
polyamides are synthetics that retain their strength indefi-
nitely. Polytetrafluoroethylene (PTFE, Gortex) is also
popular. Stainless steel was formerly popular but the
synthetic polymers have largely replaced it.
3. Modern suture materials have good strength-to-
thickness properties, so ligatures and sutures tend to be
less bulky than formerly.
Handling properties vary. Synthetic threads are
extruded (Latin ex = out + trudere = to thrust); a liquid is
forced through a hole and solidifies as a thread. If the
surface of the resulting thread is damaged, it seriously
weakens it. Monofilamentous extruded synthetics may be
rather stiff and often have a 'memory' so they spon-
taneously tend to return to the straight form in which they
were created; because the surface is so smooth it binds less
firmly to itself. These factors make the knots less secure
than those tied using flexible and rougher materials.
201
18
PREPARATIONS FOR SURGERY
Key point
• Do not injure the smooth surface of extruded
synthetic threads - it fatally weakens it.
4. Needles are now almost universally curved and
inserted using a 'no-touch' technique on a needle holder.
This protects your hands from the danger of needle stick
injury. The needles are simple round -bodied or sharp-
edged cutting needles for penetrating tough tissues. The
majority of sutures are now 'atraumatic', being swaged into
eyeless needles. This facilitates passage through the tissues.
5. Catgut was absorbed by creating an inflammatory
reaction. Modern absorbable materials are often absorbed
by hydrolysis and so provoke very little inflammatory
reaction.
6. Metal clips are valuable alternatives to ligatures
where access is difficult. They were originally made of
stainless steel and were frequently used to demarcate an
area for subsequent radiotherapy, or to assess radiologi-
cally the response of a neoplasm to treatment by radio-
therapy or chemotherapy. Stainless steel clips may produce
a stellate shadow, obscuring detail in computed tomogra-
phy (CT) scans, so they are now made from titanium.
7. Sutures or clips may be unnecessary for skin closure,
provided the tissues are perfectly apposed. Dry the edges
and apply plastic adhesive strips across the wound.
8. A variety of staples are used in visceral tissues, offer-
ing changes in practice. Be aware of the range, the indi-
cations and contraindications for each type of instrument,
including staple size, and the differences in design
between manufacturers. Remember that surgical tech-
nique may need to be adapted as compared with the stan-
dard suture procedure. However, staple techniques are
not as versatile as suturing. Reserve staple techniques for
circumstances when:
a. The procedure can be carried out with greater safety,
for example, reducing anastomotic leakage
b. Operative time is significantly reduced and this is an
important factor
c. The incidence of late complications (stenosis) is low;
for example, low anterior resection of the rectum or
oesophagogastric anastomosis high in the chest.
viscera out of the operative field, for limiting gross con-
tamination and for haemostatic control of raw surfaces.
2. Although haemostasis is usually achieved by elec-
trocoagulation, ligation, undersewing or the use of clips,
in some situations it is invaluable to use manufactured
haemostatic agents in the presence of a slow ooze. There
is a choice between Surgicel, Oxycel or Sterispon; gain
experience of the particular properties of each of them.
Surgicel applied to the gallbladder bed, with overlying
pressure from a warm, moist swab, controls a slow per-
sistent ooze following cholecystectomy. When you care-
fully remove the overlying swab, the haemostatic agent
remains undisturbed. In neurosurgery you may prefer the
more delicate Sterispon.
DISroSMLEj^CCESSORIK
Included in this category are accessories that remain on
the surface of the body, skin or epithelial lining, and those
that attain access to the interior of the body, usually for a
limited period. Remember that they cause tissue irritation
and create a break in the body's defence system.
Categories
1 . Vascular cannulae, catheters and specialized
equipment (e.g. Fogarty embolectomy catheters,
Swan-Ganz catheters).
2. Urological catheters and stents.
3. Alimentary tract stents and catheters, for example:
a. Straight, curved, cuffed or expansile stents for
oesophageal and biliary malignant stricture
b. Balloon dilating catheters for strictures
c. Enteral feeding tubes.
4. Stoma appliances.
Key point
Avail yourself of the skill of a stomatherapist
so your patient benefits from the correct
appliance in the right place.
SWABS AND PACKS
1. All cotton or fabric swabs and packs used during
operations have radio-opaque thread marking. Choose
the size appropriate to the procedure and defined
purpose. You may need small 'patty' swabs for neurosur-
gical procedures and narrow swabs for tonsillar surgery.
Use large packs or gauze rolls for retaining abdominal
5. Neurological valved shunts.
6. Drains.
Key point
Define the purpose and, therefore, duration of
use. Use closed systems.
202
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ADJUNCTS TO SURGERY
18
ENDOSCOPES
1. Endoscopes are continuously being developed,
together with new applications for diagnosis and therapy.
Instruments can be passed in the upper and lower respir-
atory tracts, the upper and lower alimentary tracts
(including the biliary tree and pancreas), the upper and
lower urinary tracts, the female genital tract, and into
joints, the peritoneal cavity and along blood vessels.
Design modifications have resulted in a wide range of
instruments with considerable therapeutic capabilities,
often with the use of specialized accessories.
2. Ensure that they are carefully stored, maintained,
cleaned, decontaminated and expertly disinfected, other-
wise there is a risk of transmitting infection, particularly
viruses such as hepatitis B and C and human immuno-
deficiency virus (HIV). Flexible instruments are usually
disinfected by immersing them in a buffered 2% solution
of gluteraldehyde for 20 min. Modern cystoscopes, for
instance, may now be autoclaved.
3. Do not neglect to master the use of the simple proc-
toscope, anal retractor, such as Park's or Eisenheimer's
retractors, and sigmoidoscope.
IMPLANT MATERIALS
1. Prosthetic (Greek pros = to + thesis - putting; the
fitting of artificial parts into the body) surgery continu-
ously expands. Perhaps the greatest impact is in
orthopaedic surgery, where successful joint replacement
is well established in the hip, knee, interphalangeal joints
and, to a more limited extent, the shoulder and elbow
joints.
2. Prosthetic implants are widely used in general, vas-
cular, cardiac, urological, plastic and other branches of
surgery, and there is wide variation in the materials
used. Basic considerations and principles apply. They
must be easily and reliably manufactured at reasonable
cost. The strength and durability must be reliable,
especially for cardiac valves, pacemakers and joint
replacements.
3. There must be no adverse reaction between pros-
thetic materials themselves and the body tissues; for
example, between the metal and plastic components of
certain artificial hip replacements or between the joint
prosthesis, cement and the bone. Another example is
platelet aggregation and plasma protein precipitation
around intravascular prostheses.
4. The degree of incorporation into the body may be
important; for example, metallic and silicone implants
are isolated within a collagen capsule but polytetra-
fluoroethylene (PTFE, Goretex) allows the ingrowth of
fibroblasts.
Implant materials in orthopaedic surgery
1. Surgical-grade stainless steel is used for joint
replacement-bearing surfaces, plates, screws and wires.
2. Alloys, including Vitallium, are also used in joint
replacement surfaces, wires and, less frequently now
owing to the preference for compression steel plating for
internal fixation, in plates.
3. High density polyethylene (ultrahigh molecular
weight) is used for joint replacement-bearing surfaces to
articulate with steel or Vitallium.
4. Silicone is used for hinge-type joint replacement, but
not in bearing surfaces where debris produces a synovi-
tis. It has been used very successfully in metacarpo-
phalangeal and proximal interphalangeal joints.
5. Dacron and PTFE are materials that can be used
under tension (e.g. synthetic ligament repair). Carbon
fibre has been abandoned as a result of fragmentation and
foreign body reaction.
The risk of infection
This is one of the most serious complications of prosthetic
surgery. Risk factors include:
• Immune compromised host
• Active infection present elsewhere in the host or in
contacts
• Positive carrier state in patient or staff
• Crossinfection in hospital
• Failure of sterilization and /or packaging
• Inadequate air ventilation in the operating theatre and
ineffective operating theatre clothing
• Poor operative technique with contamination, poor
haemostasis or ischaemic tissue
• Inadequate antimicrobial prophylaxis.
The time scale of presentation is of significance. Late
infection may develop, up to a year or more after surgery,
particularly with a deeply inserted prosthesis. A smooth-
surfaced implant is bacteriostatic and non-wettable,
whereas a textured surface allows the entrapment of
blood, serum, particles and bacteria in the crevices.
Deep infection around implants, such as of a hip
replacement with Staphylococcus aureus , produces a cap-
sular thickening; S. epidermidis produces a polysaccharide
slime. The prosthesis becomes loose, causes pain and may
need to be removed.
Do not use an implant unless there is no natural alter-
native. Thus, in vascular surgery prefer vein grafts for
lower limb arterial bypass surgery such as infrainguinal
bypass and especially for below-knee femoropopliteal
bypass. Synthetic materials, Dacron (collagen-coated
knitted Dacron) or Goretex (PTFE) may be used, particu-
larly where large vessels need to be bypassed or replaced.
203
is ;
PREPARATIONS FOR SURGERY
Tissue response to foreign material
1 . Tissue reaction varies according to the material and
the roughness of the surface. Marked inflammatory
response / with microabscess formation, occurs around a
buried silk or linen knot. By comparison, minimal
response occurs around polypropylene, with not only a
reduced likelihood of bacterial infection but also
increased tensile strength, depending on the material
used, and a lack of surrounding tissue inflammatory
infiltrate.
2. Silicone generates the formation of a capsule.
Fibroblasts orientate themselves to the surface of the
foreign material and the collagen is laid down in mirror
image to the specific surface; as it matures, it contracts.
Fibroblasts cease to secrete collagen when they are in
contact with other fibroblasts, but not when in contact
with other cells. Thus, over a smooth surface sheets of col-
lagen are produced with increased contractile force of the
capsule. Gradually, fibroblastic activity on the free surface
subsides, collagen deposition is completed and moulding
takes place, producing a mature capsule at approximately
3 months after surgery. Collagen production against the
smooth inner capsular surface continues because the
fibroblasts are not in contact with each other and, as a
result, the cavity diameter decreases and the contractile
force increases.
3. By comparison, roughened surfaces allow fibro-
blasts to conform to the crevices; the fibres of collagen are
then orientated at random with counteracting contractile
forces and the fibroblasts lie in different planes and direc-
tions, allowing a greater chance of contact with each
other, thus reducing the collagen deposition and resulting
in a thinner capsule. Silicone particles are found in phago-
cytes in the capsule wall adjacent to lymphatic vessels, in
the outer layer of capsules, and may reach the lumen of
lymphatic vessels, as they are found in regional lymph
nodes.
4. Metal-on-metal joint replacement produces small
particulate debris which is incorporated into the syn-
ovium, producing foreign-body giant cells.
5. Acrylic cement (polymethylmethacrylate), used in
the fixation of prostheses, becomes encapsulated by
fibrous tissue, the inner layer of which is sometimes
hyaline and acellular and sometimes contains histiocytes
and multinucleate giant cells. There is no evidence for
malignant transformation or chronic inflammatory reac-
tion with sinus formation (Charnley 1970). Revisional
surgery of the cemented prosthesis is difficult.
Alternatives under trial are based on isoelastic or mesh
coating of the prosthesis to allow fibrous tissue to grow
in.
The controversy over the safety of silicone
mammary prostheses
In 1992 in the USA a moratorium {Latin mora = delay) was
placed on the use of silicone gel breast implants because
of the possible association with connective tissue dis-
orders. In the UK, an independent expert advisory group
reported to the Department of Health in 1993 that there
was no evidence of an increased risk in implanted patients
(Park et al 1993). In 1994, the Medical Devices Directory
supported the Chief Medical Officer in stating that there
was no evidence for a change in policy. As always, absence
of evidence is not evidence of absence. Since the incidence
of connective tissue disorders in the population is low and
the latent period is long, large numbers and prolonged
follow-up are needed. Silicone, like any foreign body, may
initiate an antibody and cell-mediated inflammatory
response, but this is not in itself suggestive of an adverse
effect on the immune system. There is currently no evi-
dence that breast-implanted patients have an enhanced
risk of developing either autoimmune connective tissue
disease or mammary carcinoma. Silicone implants do,
however, reduce the value of mammography. Alternative
filler substances, developed to allow mammograph and
avoid silicone reaction locally, include triglyceride and
saccharides. They were withdrawn because of adverse
reactions in some patients (Medical Devices Agency 2001)
and patients are advised to have them removed, to be
replaced by silicone gel or saline filled prosthetics if
desired. All of them have textured silicone shells.
ITSSUEjGI^
Glues have been used for many years. Collodion, a cellu-
lose nitrate, has been used for many years as a wound
seal. Karaya gum is routinely used to attach stoma bags
to the skin; it has also been used as a slow release vehicle
for caffeine and diclofenac. Cyanoacrylate 'instant glue' is
used as a tissue glue. Gelatine-resocinol-formaldehyde
has been used, for example, as an adhesive to fix a patch
sealing an intraventricular septal defect.
Research into new methods of surgical tissue repair has
yielded the prospect of wide use of tissue glues. One such
method is fibrin adhesion, based on the conversion of
fibrinogen into fibrin on a tissue surface by the action of
thrombin. The fibrin is then crosslinked by factor XHIa to
create a firm stable fibrin network with good adhesive
properties. Fibrin foam may be valuable in controlling
tumour bleeding. The addition of aprotinin prevents pre-
mature dissolution of the fibrin clot by plasmin. In the
presence of heavy bleeding the fibrin glue tends to be
204
ADJUNCTS TO SURGERY
18
washed away before sufficient polymerization of the
fibrin has occurred. The use of collagen mesh sheet with
fibrin glue dispersed over the surface has been of con-
siderable practical value. Note that the sheet should be
kept in contact with the surface by gentle pressure for 3-5
min. The indications are for tissue adhesion, haemostasis
and suture support (Table 18.1).
Concern has been expressed that the use of human fib-
rinogen and factor XIII might allow the transmission
of viral agents such as hepatitis B, hepatitis C or HIV.
Commercial inactivation of a virus is achieved by pas-
teurization with purification of the proteins and then
heating the solution for 10 h at 60°C. Laboratory studies
demonstrated that this process not only inactivates the
hepatitis B and HIV viruses, but also herpes simplex virus
and cytomegalovirus. Particular care is taken to use
human fibrinogen from hepatitis B antigen-negative,
ji
Table 18.1 Examples of the use of tissue glues
General surgery
Trauma to or surgery of liver, spleen, pancreas
Haemostasis in gallbladder bed (cheaper agents
currently available)
Support anastomosis eg, pancreaticojejunal
anastomosis
Neurosurgery
Repair of dural tear, sealing cerebrospinal fluid
leak
Peripheral nerve anastomosis
Orthopaedic surgery
Acetabuloplasty (cement-free prosthesis)
Tendon repair
Re-attaching osteochondral fragments
Cardiovascular and thoracic surgery
Prosthetic implant in combination with collagen
sheet to seal lung air leaks
Ophthalmic surgery
Cataract operations
£ NT surgery
Tympanic membrane surgery
Sealing CSF leaks
Urology
Haemostasis, especially after TURP
Plastic surgery
Attaching skin grafts
anti-HIV-negative and anti-hepatitis C-negative plasma
of healthy donors.
Marked arterial or venous bleeding renders the system
ineffective. Hypersensitivity reactions have been
described. The process is under evaluation in the UK.
Summary
• Do you recognize the safety factors and
cost effectiveness of good theatre
management for you and your patient?
• Do you know the basic principles of
sterilization?
• Will you contribute to cost savings by
using only the smallest range of effective
instruments, equipment and consumable
materials?
• Implants can transform a patient's quality
of life but the surgery is costly and
complications can be serious and
prolonged.
Further reading
Detweiler MB, Detweiler ]G, Fenton J 1999 Sutureless and
reduced suture anastomosis of hollow vessels with fibrin
glue: a review. Journal of Investigative Surgery 12: 245-262
Gosden PE, MacGowan AP, Bannister GC 1998 Importance of
air quality and related factors in the prevention of infection
in orthopaedic surgery. Journal of Hospital Infection
39: 173-180
Harding KG, Jones V, Price P 2000 Topical treatment: which
dressing to choose. Diabetes/ Metabolism Research Reviews
16 (suppl. 1): S47-S50
References
Charnley J 1970 Acrylic cement in orthopaedic surgery. E and S
Livingstone, Edinburgh
Park AL Black RJ, Watson ACH 1993 Silicone gel breast
implants, breast cancer and connective tissue disorder, British
Journal of Surgery 80: 1097-1100
205
1Q Prevention of infection in
I Z7 surgical practice
K. E. Orr, F. K. Gould
H
Objectives
Appreciate the importance of surgical
sepsis as a significant cause of morbidity.
Understand the principles of infection
control and its role in preventing
infections.
Be aware of methods by which asepsis and
antisepsis are achieved, and when they are
necessary.
Know when antibiotic prophylaxis is
desirable and when it is not.
Recognize the benefit of infection audit
with feedback to surgeons as a means of
reducing the infection rate.
INTRODI^^
The Hungarian obstetrician Ignaz Semmelweiss was the
first to demonstrate the importance of antisepsis,
working in Vienna in the early 1850s. He found that on
his obstetric ward attended by medical students almost
one-fifth of all his patients died, usually of puerperal
(Latin puer = child + parere = to bear) sepsis. On another
ward, without medical students, the mortality was about
3 in 100. He realized that the medical students came
straight from the autopsy room and proceeded to
examine his patients without so much as washing their
hands. Having insisted that each student should do so
with soap and water and then in chlorinated lime solu-
tion before entering the ward, he saw the mortality rate
drop to less than 2 in 100. Despite this dramatic result,
Semmelweiss was largely ignored and even ridiculed. It
was not until Joseph Lister built on Pasteur's germ theory
of disease in Glasgow in the late 1860s that antisepsis was
looked at seriously.
Since then, the improved prevention and management
of infections in surgical practice has been one of the most
important factors allowing the development of surgery as
we now know it. Even so, surgical wound infections
remain an important cause of morbidity. Over 70% of
hospital-acquired infections occur in patients who have
undergone a surgical procedure. Of these, wound infec-
tions are those that increase hospital costs and length of
hospital stay the most. On average, wound infections
prolong the hospital stay of the patient by 7 days.
Surgical wounds are traditionally classified as follows:
Clean (Class I)
These are wounds created during surgical procedures in
which the respiratory, genitourinary or gastrointestinal
tracts have not been entered. The usual causes of infec-
tions in these wounds are airborne or exogenous bacteria
that have entered the wound during surgery, or, in the
case of prosthetic implants, the patient's own skin flora.
The infection rate should not exceed 2%.
Clean-contaminated (Class II)
This term (Latin con - together + tangere = to touch;
hence, soiled) describes wounds in elective surgery
where the respiratory, gastrointestinal or genitourinary
tracts have been entered. The primary cause of infection
is the endogenous flora of the organ that has been
breached surgically. The infection rate has been found to
be approximately 5%.
Contaminated (Class III)
These are wounds where acute inflammation (but not
pus) was found at surgery, or where there was spillage of
gastrointestinal contents. They become infected with
bowel /endogenous flora at a rate of about 20%.
Dirty (Class IV)
These are wounds where pus was found at operation,
usually following organ perforation, although this cat-
egory also includes contaminated traumatic wounds. The
infection rate is up to 40%.
206
PREVENTION OF INFECTION IN SURGICAL PRACTICE
19
Not only are surgical infections extremely important
to the outcome for individual patients and costly for
hospitals, but they have also assumed medicolegal sig-
nificance. All departments and surgeons should ensure
that their infection rates are compatible with those in
other units, using methods that will be discussed later in
this chapter.
You cannot reduce infection by
concentrating attention in a single
area
• Control resistant organisms in all areas within
the hospital.
• Unfailingly adhere to aseptic and antiseptic
principles.
• Practise the highest standards of surgical
technique.
• Use prophylactic antibiotics logically.
• Audit your results to maintain and improve
standards.
CONTROL OF RESISTANT ORGANISMS
1. Antibiotics have been in use for more than 50 years
and many organisms are now resistant to the older
agents. For example, in many hospitals more than 50%
of isolates of Escherichia coli are resistant to ampicillin.
The development of newer agents with increased
activity and wider spectrum has allowed the benefits
of antimicrobial therapy to be maintained and even
improved. However, increasing use of these has led to
the emergence of resistance in some important pathogen
groups.
2. The most obvious example is methicillin-resistant
Staphylococcus aureus (MRSA). This is resistant to the com-
monly used antistaphylococcal agent flucloxacillin and
has to be treated with drugs such as the glycopeptides,
vancomycin and teicoplanin. As well as being more toxic,
these agents penetrate less well into soft tissues and
wounds, can only be given parenterally and are expen-
sive, MRSA is of particular concern in fields such as
burns, plastic surgery and orthopaedics where tissue pen-
etration of the antibiotic is of paramount importance and
where an infection may result in removal of a prosthesis
or failure of a graft. Even more worrying is the reported
emergence in Japan and the USA of vancomycin interme-
diate S. aureus (VISA) with reduced susceptibility to
vancomycin. So far this does not appear to be a common
cause of clinical infections, however there is a danger
that in the future we shall again be unable to treat
S. aureus infection.
3. Enterococci are also posing major problems with
resistance; glycopeptide-resistant enterococci (GRE) are
now found in many UK hospitals and, although they are
less virulent than MRSA, they may cause life-threatening
infections in immunocompromised patients.
4. Gram-negative organisms such as Pseudomonas aeru-
ginosa may also be multiresistant. The increasing use of
third-generation cephalosporins appears to be encouraging
the emergence of Gram-negative bacilli such as Klebsiella
pneumoniae and Enterobacter cloacae resistant to these and
other beta- lactams.
Key point
• Make every effort to keep the prevalence of
resistant organisms within the unit to a
minimum, and prevent their spread between
patients.
5. Handwashing and basic infection control practices
cannot be overemphasized. Handwashing has been high-
lighted in recent national evidence-based guidelines for
preventing healthcare-associated infections (Pratt et al
2001). Most hospital acquired (nosocomial from Greek
nosos = sickness + komeein = to tend; hospital) infections
are transmitted on the hands of staff and many studies
have shown that handwashing is the single most import-
ant and successful method of controlling the spread of
infection in hospital. Wash your hands before and after
physical contact with any patient, and after any activity
where they are likely to become contaminated. Wash
them with soap, detergent, or with alcohol rubs or gels if
your hands are not visibly soiled. Before carrying out
aseptic procedures, wash with an antiseptic solution such
as povidone-iodine or chlorhexidine.
Key points
• Wash your hands, and see that all members of
your team do so, before and after contact with
every patient.
• Rigorously apply universal precautions when
appropriate, to minimize risk of infection for
colleagues and patients (see Ch. 20).
6. Screen at-risk patients to identify those who are col-
onized. Reserve this, as a rule, for detecting MRSA so you
can implement precautions to prevent spread of the
organism to other patients, and also to reduce the risk of
infection in those planned for high risk surgery such as
207
19
PREPARATIONS FOR SURGERY
vascular graft procedures and prosthetic orthopaedic
surgery. Take swabs of nose, throat and perineum.
Colonized patients are asymptomatic and do not require
systemic antibiotic treatment unless they show clinical
evidence of infection. Consider using topical agents in an
attempt to eradicate MRS A carriage in colonized patients;
however, this is unlikely to succeed in the presence of
foreign bodies such as percutaneous feeding tubes, and
persisting wounds. If there is evidence of an outbreak on
your unit, the infection control team may advise you to
screen the unit staff, in case there are carriers. In most UK
hospitals the management of patients and staff in units
affected by MRSA is based upon national guidelines
(Duckworth et al 1998).
7. Isolate patients found to be colonized with a sig-
nificant multiresistant organism, usually in a side room
- "wound and enteric' or 'source' isolation. All staff wear
disposable gloves and aprons when in contact with the
patient. You and your medical colleagues remove your
white coats before entering the side room. Ideally the
same nurses should care for the patient throughout the
shift. All other staff, such as porters, physiotherapists,
phlebotomists and domestics, must be aware of, and
take relevant precautions for, 'wound and enteric/
source isolation.'
8. Control the movement of colonized patients
between departments. Whenever possible, arrange for
those carrying multiresistant organisms to be operated
upon at the end of the surgical list, so that the theatre can
be cleaned thoroughly afterwards with minimum disrup-
tion. Warn the theatre staff of the patient's status in
advance. The same applies to visits to other departments,
such as radiology, physiotherapy and the gymnasium.
Keep patient movement within the hospital to a
minimum and transfer patients between wards only
when absolutely necessary
9. Use antibiotics judiciously, only when there is evi-
dence of clinical infection or as part of a policy regarding
perioperative prophylaxis. Choose the antibiotic ratio-
nally; if in doubt, consult the microbiologist earlier rather
than later. Overuse of antibiotics encourages develop-
ment of resistance in exposed organisms. It also destroys
patients' normal flora so they are more susceptible to
colonization with hospital organisms. Furthermore, it
predisposes to infection with Clostridium difficile, which
can lead to pseudomembranous colitis: third- generation
cephalosporins are notorious for this.
ASEPSIS AND ANTISEPSIS
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■Wi
Key point
• Adopt locally agreed guidelines for antibiotic
prescribing, and audit your infection rates.
The term 'asepsis' (Greek a - deprive + $ey$i$ - sepsis =
putrefaction) describes methods preventing contamin-
ation of wounds and other sites by ensuring that only
sterile objects and fluids come into contact with them; the
risks of airborne contamination are minimized. Antisepsis
(Greek and = against) is the use of solutions, such as
chlorhexidine, iodine or alcohol, for disinfection.
Theatre clothing
1. Gowns. Woven cotton clothing is relatively ineffec-
tive at preventing the passage of bacteria. Choose
disposable non-woven fabric, Goretex or tightly woven
polycottons. The Charnley exhaust gown is of some
benefit in prosthetic implant surgery. It is an important
part of theatre discipline to change into fresh theatre
clothing when entering the theatre suite because clothing
worn in ward areas has been shown to be more heavily
contaminated with microorganisms than freshly laun-
dered 'scrub suits'.
Normal cotton clothing does little to prevent the
passage of bacteria, especially those on skin scales, as the
diameter of holes at the interstices of the cloth is usually
greater than 80 iJim. In addition, once cotton material is
wet its barrier properties are much reduced, allowing
bacteria to penetrate through from the wearer's skin;
therefore, if clothes become wet, change them. 'Soak
through' of blood has been shown to occur in over one-
third of orthopaedic and general surgical operations and
may present a risk to the wearer. Reduce the risk by
using impermeable gowns or by wearing plastic aprons
under linen gowns in situations where 'soak through' is
likely.
Materials that reduce the dispersal of skin scales and
bacteria are restrictive to wear so a compromise has to
be reached. Clothing made from disposable non- woven
fabric is suitable but expensive, as the whole team must
wear it to obtain a benefit. Breathable membrane fabrics
such as Goretex, or other materials such as tightly-woven
washable polycottons are also suitable. Pay special atten-
tion to the design of the clothing so that bacteria are not
'pumped out' at the neck or the ankles. Most effective of
all is the Charnley exhaust gown, which for maximum
benefit must be used in conjunction with a unidirectional
high efficiency particulate air (HEPA) filter system. It
is also very restrictive and so rarely used by general
surgeons. However it can be valuable in orthopaedic
prosthetic surgery.
2. Mask use is controversial. Few bacteria are dis-
charged from the mouth and nose during normal breath-
ing and quiet conversation, and it is argued that for
general abdominal operations masks are not required for
208
PREVENTION OF INFECTION IN SURGICAL PRACTICE
19
the protection of the patient, particularly by staff
members in theatre who are not directly assisting. If you
wear a mask, change it for each operation; reuse and
manipulation simply contaminates the outside of the
mask with skin commensals. Masks have been shown to
reduce airborne contamination in ultraclean air theatres
and should therefore be worn in prosthetic implant
surgery
An efficient mask must be capable of arresting low
velocity droplets. Paper masks become wet within a few
minutes and lose their barrier qualities, so do not use
them. Disposable masks made of synthetic fibres are
better and contain filters made of polyester or polypropyl-
ene. Surgical antifog masks with flexible nosebands are
available; they follow facial contours and retain a high
efficiency of filtration.
Masks continue to be worn to provide protection for the
wearer against blood-borne viruses as part of a policy of
universal (or standard) precautions. Full-face visors also
afford similar protection.
3. Eye protection /visors also protect mucous mem-
branes. Wear them during any procedure that is likely to
generate droplets of blood or other body fluids, in order
to protect your mucous membranes from blood-borne
viruses. A variety of lightweight anti-fog goggles,
glasses and visors are available that do not obstruct
vision.
4. Tie up long hair and cover hair completely with a
close-fitting cap made of synthetic material. Cover beards
fully with a securely tied mask and hood of the balaclava
type. This is especially important for prosthetic implant
surgery.
5. Footwear has a minor role in spreading infection.
There is little evidence that the floor plays a significant
role in the spread of infections in hospital. Wear clean,
comfortable, antislip and antistatic shoes. If there is a risk
of fluid spillage, as in genitourinary surgery, wear ankle-
length boots that can be cleaned with warm soapy water.
Make sure your footwear fits well and does not produce
a "bellows' effect. Make sure they are sufficiently robust
to protect your feet from sharps injury. Overshoes are not
required for visitors who do not enter the operating or
preparation rooms.
6. Gloves protect both you and your patient from
blood-borne viruses (see Ch, 20) and prevent the wound
from becoming contaminated with your skin flora. Wear
single-use surgical gloves from a reputable source, steril-
ized by irradiation.
Surgical gloves made of natural rubber (latex) are increas-
ingly reported to cause hypersensitivity reactions. Non-
latex gloves without powder are available. Worryingly,
many gloves are found to have pre-existing holes prior
to use, as a result of inadequate quality control and poor
manufacture. Furthermore, during the operation, around
20-30% develop holes of which the wearer is often
unaware. Therefore inspect them at the end of each oper-
ation. Avoid needlestick injury; if you sustain one, let it
bleed, and wash well with soap and water. As soon as pos-
sible fill in the accident form and report to the occupational
health department.
Double-gloving affords extra protection but at the
expense of reduced sensitivity and dexterity, and possible
discomfort. In appropriate circumstances protect your
fingers with armoured gloves or thimbles, in addition to
protective clothing.
Theatre air
1. Air-borne bacteria are generally believed to be a
source of postoperative sepsis, although this has been
unequivocally proved only in the case of prosthetic
orthopaedic implant infections. The number of circulating
bacteria is directly related to the number of people in
theatre, and their movements, which should both there-
fore be minimized. It is also affected by the type of theatre
clothing worn.
Carefully balanced ventilation systems will not operate
optimally if theatre doors are left ajar.
2. General operating theatres are equipped with posi-
tive pressure or plenum (Latin = full) ventilation systems,
with the pressure decreasing from theatre to anaesthetic
room to entrance lobby. Thus air-borne microorganisms
tend to be carried out rather than in. In a conventional
plenum system there should be a minimum of 20 air
changes per hour. Routine checks of bioload are not
required. Guidelines regarding theatre air ventilation and
theatre design can be found in the Department of Health
documents Health Technical Memorandum 2025,
Ventilation in Health Care Premises, and Health Building
Note number 26, Operating Department.
3. Ultraclean air systems are advocated for prosthetic
implant surgery. In these systems, instead of the turbulent
airflow associated with plenum pressure systems, there is
unidirectional or laminar airflow at about 300 air changes
per hour. The air is recirculated through high efficiency
particulate air (HEPA) filters. This produces a reduction
in circulating microorganisms compared with a conven-
tional system. In these theatres regular bacteriological
assessment should be undertaken.
A large multicentre study in prosthetic orthopaedic
surgery demonstrated that the incidence of deep peri-
articular infections was reduced from 3.4% to 1.6% by the
use of ultraclean air conditions. With the addition of
prophylactic antibiotics, the infection rate was reduced
further to 0.19%. Bear in mind that, if the level of asepsis
is otherwise only moderate, the impact of ultraclean air
systems may be lost. Their role in clean surgery other than
prosthetic implant surgery is uncertain.
209
19
PREPARATIONS FOR SURGERY
Surgeon preparation
1 . Most theatre-acquired infections are of endogenous
origin, but the scrub team must ensure that they do not
put their patients at risk. In order to minimize the risk of
transmitting infection to patients, you must all satisfy
local occupational health requirements before entering
the operating theatre. For example, you must not operate
with bacterial pharyngitis, during the prodromal (Greek
pro = before + dromos = run, course; hence, incipient)
period of a viral illness or with chronic or infected skin
conditions. Try to avoid operating if you have cuts,
cracks, sores or rashes on your hands or forearms. If
in doubt take advice from the occupational health
department. The Department of Health has issued com-
prehensive guidance regarding healthcare workers
infected with blood-borne viruses (see Ch. 20).
2. The term 'scrubbing up' is unlikely to disappear
from surgical practice but repeated scrubbing is counter-
productive because it results in skin abrasions and more
bacteria being brought to the surface. At the start of a list
have an initial scrub of 3-5 minutes; thereafter, use effec-
tive handwashing with an antiseptic between cases. Skin
antiseptics act rapidly and some have a cumulative
effect. Use sterile, single-use brushes of polypropylene,
not with wood or bristles. Do not shower prior to oper-
ating, it increases the number of bacteria shed from the
skin.
3. Antiseptics commonly used are:
a. Chlorhexidine gluconate 4% (Hibiscrub), which is
rapidly active, broad spectrum and persists with a cumu-
lative effect, even under surgical gloves. It is easy to use
but the detergent-like effect must be washed off with
running water. Some surgeons are allergic to it and can
use hexachlorophane or povidone-iodine.
b. Hexachlorophane (pHisoHex), which is effective
only against Gram-positive bacteria and has a slow action
but a cumulative effect.
c. Povidone-iodine (Betadine), which acts more
rapidly than hexachlorophane and has a broader spec-
trum but does not have a prolonged effect.
4. Dry your hands thoroughly using single-use sterile
towels. Hot-air drying machines are not recommended.
Preparation of the patient
1. The longer a patient stays in hospital before oper-
ation, the greater the likelihood of a subsequent wound
infection. Keep hospital stay as short as possible and carry
out as many tests as possible beforehand, as an out-
patient. Cultures from postoperative wound infections
often suggest that organisms are transferred from other
areas of the patient to the operative site (endogenous
transfer) despite the use of antiseptics. Ensure that the
patient is socially clean prior to operation. The value of
routine preoperative showering with antiseptic solutions
remains unproven. Infections at other sites increase the
risk of surgical wound infection; therefore, diagnose and
treat pre-existing infections before elective operation.
Similarly, consider eradicating MRSA carriage in colo-
nized patients prior to elective surgery.
2. The patient can be transported to theatre in bed
directly, after being changed into a clean operating gown.
Remove ward blankets before entering theatre. There is
no need for a special transfer area, changing trolleys,
porters putting on plastic overshoes, or passing the
trolley wheels over a sticky mat. Trolleys must be cleaned
daily.
3. Shaving of the operation site increases wound infec-
tion rates because of injury to the skin. If hair removal is
necessary, use clippers or depilatory cream. If it is essen-
tial to shave the area, it should be performed as near as
possible to the time of operation, preferably by you, prior
to scrubbing up.
4. Prepare the skin area around and including the oper-
ation site. First scrub it with a sponge or swab impreg-
nated with detergent. After the skin has been cleaned and
degreased in this way, use antiseptic solutions. For intact
skin consider alcoholic solutions of chlorhexidine or
povidone-iodine rather than aqueous solutions. However,
take care when applying alcohol solutions if you use
diathermy; if it pools in the umbilicus or under the per-
ineum, you may cause fire hazard. For vaginal or perineal
disinfection consider a solution of chlorhexidine and
cetrimide (Savlon).
5. Traditionally the periphery of the proposed incision
site was protected with sterile cotton drapes; however,
these soon become wet, diminishing their protective
properties. Incisional plastic drapes have been advocated
but Cruse & Foord (1980) showed that applying adhesive
plastic drapes to the operation area does not decrease the
wound infection rate; this has since been confirmed in a
study of caesarean section.
Cleaning and disinfection
1. Decontamination, or the process of removing micro-
bial contaminants, can be carried out by cleaning, dis-
infection or sterilization. The appropriate method of
decontamination is determined by the risk of infection
associated with the object or procedure.
a. Cleaning is a process that removes visible contami-
nation but does not necessarily destroy microorganisms.
It is a necessary prerequisite to effective disinfection or
sterilization.
b. Disinfection is a process that reduces the number of
viable microorganisms to an acceptable level but may not
210
PREVENTION OF INFECTION IN SURGICAL PRACTICE
19
inactivate some viruses, hardy organisms such as
mycobacteria and bacterial spores. A topical disinfectant
that may safely be applied to epithelial tissues is known
as an antiseptic.
Where an interventional procedure is planned for a
patient known, suspected or at risk of suffering from a
transmissible spongiform encephalopathy (TSE) such as
Creutzfeldt-Jakob disease (CJD) or variant CJD, seek
advice from the infection control team and sterile service
department.
2. Disinfection of heat-tolerant items can be achieved
reliably by exposure to moist heat; for items such as sur-
gical equipment and bedpans it can be carried out using
a washer-disinfector. Recommended time-temperature
combinations are 71 °C for 3 min, 80°C for 1 min or 90°C
for 12 s. Boiling water kills bacteria, some viruses (includ-
ing human immunodeficiency virus (HIV) and hepatitis
B virus (HBV)) and some spores. It does not sterilize. Soft
water at 100°C at normal pressure for 10 min is satisfac-
tory. Suitable instruments include specula, proctoscopes
and sigmoidoscopes. This method is now rarely used in
secondary care.
3. Chemical disinfection can be used where heat
cannot. A good example is the use of glutaraldehyde 2%
(Cidex) to decontaminate flexible endoscopes. It is rapidly
active against most vegetative bacteria and viruses
(including HIV and HBV), and slowly effective against
tuberculosis and spores. It is toxic, irritant and allergenic.
Other chemical disinfectants include hypochlorite solu-
tions, chlorine dioxide, superoxidized water and peracetic
acid.
Those involved in the purchase and development of
new instrumentation for surgery or investigation need
to consider how it may be decontaminated at the end of
the procedure. Recent years have seen the introduction
of increasing numbers of instruments that cannot be
sterilized and can be disinfected only with difficulty. As
sterilization by heat is the most reliable and easily moni-
tored method, choose reusable instruments that will
withstand autoclaving, if possible. Reprocessing of dis-
posable equipment is hazardous and must not be carried
out.
Antiseptics include chlorhexidine, iodophors such as
povidone-iodine, triclosan and 70% alcohol.
Sterilization
This is defined as the complete destruction of all viable
microorganisms, including spores, viruses and mycobac-
teria. It is, in practice, defined in terms of the probability
of a single viable microorganism surviving on 1 million
items. The term sterilization (Latin sterilis = barren) can be
applied only to equipment and not to the skin, where
antisepsis alone can be achieved.
1. Steam under pressure attains a higher temperature
than boiling water and the final temperature is directly
related to the pressure. Instruments can be cleaned, then
reliably sterilized by steam under pressure using auto-
claves. The process can kilUbacteria, including Myco-
bacterium tuberculosis, viruses and heat-resistant spores.
The preferred cycle is 134°C at 2 atmospheres for a
holding time of 3 min, which entails a total cycle time of
at least 30 min to reach the required temperature.
Autoclaves should be centralized in specialized units, e.g.
the sterile service department (SSD) or theatre sterile
service unit (TSSU) and maintained by highly trained
personnel. Maintenance and performance tests are very
strictly controlled. In the future there will be a require-
ment for systems tracing the decontamination processes
of surgical instruments.
Small portable autoclaves are used in some theatres for
convenience. There is a potential danger in that they are
used by staff untrained in scrutinizing and maintaining
them. Many portable autoclaves are unsuitable for pro-
cessing wrapped instruments or those with a narrow
lumen.
In patients at risk of TSE, for procedures not involving
high risk tissues, use the autoclave, after thorough clean-
ing of the instruments, with a cycle of 18 min at 134°C or
six cycles of 3 min.
2. Destroy instruments used for invasive procedures
on patients known to have TSE, using incineration (ACDP
1998). The same applies to instruments used on patients
suspected of having TSE, unless an alternative diagnosis
is established, and for instruments coming into contact
with high risk tissues, such as brain, spinal cord or the
eye, in patients at risk of developing TSE. Therefore,
when possible use single-use instruments.
3. Sterilization can be achieved by dry heat at 160°C
for a holding time of 1 h. The process is inefficient com-
pared with steam sterilization, but has the advantage of
being able to treat non-aqueous liquids, ointments and
airtight containers. It is also useful for avoiding corrosion
of non-stainless metals and instruments with fine cutting
edges, such as ophthalmic instruments. Do not use it for
aqueous fluids or for materials that are likely to be
damaged by the process, such as rubber and plastics.
This equipment is subject to rigorous checks and
maintenance.
4. Sterilants are chemical compounds that, under
defined conditions, are able to kill bacterial spores:
a. Ethylene oxide (EO) is a highly penetrative, non-
corrosive agent with a broad cidal (Latin caedere = to kill)
action against bacteria, spores and viruses; however, it is
also flammable, toxic, irritant, mutagenic and poten-
tially carcinogenic, and should not be used when heat
sterilization is possible. Its main uses are for wrapped
and unwrapped heat-sensitive equipment: it is ideal for
211
19
PREPARATIONS FOR SURGERY
electrical equipment, flexible-fibre endoscopes and
photographic equipment. Do not use it for ventilatory
equipment. It is inappropriate for items with organic
soiling. EO sterilization is a mainly industrial process for
single-use medical devices. There are a limited number
of NHS regional units. It is expensive, has a slow
turnaround time, is potentially dangerous and must be
carefully controlled and monitored.
b. Glutaraldehyde: shorter immersion times provide
disinfection, but 3-10 h of exposure to 2% alkaline glu-
taraldehyde is required for sporicidal activity.
c. Other sterilants include peracetic acid, superoxi-
dized water, gas plasma and chlorine dioxide; however,
validation processes have not yet been established by
the Department of Health for some of these newer
technologies.
5. Irradiation employs gamma rays or accelerated elec-
trons. It is an industrial process suitable for sterilizing
large batches of similar products, such as catheters and
syringes.
Spillages
Have body fluid spillage removed as soon as possible.
Gloves and a plastic apron should be worn. First, cover
spills with an appropriate disinfectant such as hypo-
chlorite granules (Presept), then absorbent paper towels.
Discard as clinical waste. Do not use chlorine-releasing
agents on urine spills or chlorine gas will be released.
Waste disposal
Sort hospital waste to ensure it is correctly disposed of.
Place 'sharps' in approved containers, and clinical waste
in yellow plastic bags. These are disposed of, usually by
incineration, separately from domestic waste, which may
be sent for landfill. Other categories of waste requiring
segregation include pharmaceuticals and radioactive or
cytotoxic waste.
SURGICAL TECHNIQUE
Postoperative infection rate is influenced by the following
factors.
• The longer the operation, the more likely is the wound
to become infected. Perform operations as expediently
as safety allows.
* Keep operative trauma to a minimum and handle
tissues gently.
Make incisions with sharp instruments - they are less
likely to become infected than those produced, for
example, by cautery; however, cautery may reduce the
need for sutures, which can act as a nidus for infection.
Use the finest suitable ligature.
Haematomas are at risk of becoming infected.
Necrotic or ischaemic areas are at risk.
Avoid leaving a dead space.
Avoid unwarranted prophylactic drains, which increase
the risk of infection. Insert a necessary drain through a
separate stab, not through the wound. Use an entirely
closed system to decrease the chance of ascending infec-
tion, and remove it as soon as possible.
Key point
Why do some surgeons performing standard
operations have minimal infection? Their
technique is impeccable!
PROPHYLACTIC ANTIBIOTICS
It has been shown that, for many contaminated and clean-
contaminated procedures, postoperative infection can be
avoided by using appropriate prophylactic antibiotics
given prior to surgery. The general principles of antibiotic
prophylaxis (Greek pro = before + phylax = a guard) are as
follows:
1. Use antibiotic prophylaxis only when wound con-
tamination is expected or when operations on a contami-
nated site may lead to bacteraemia. It is not required for
clean-wound procedures except:
a. When you insert an implant or vascular graft
b. In valvular heart disease to prevent infective
endocarditis
c. During emergency surgery in a patient with pre-
existing or recently active infection
d. If an infection would be very severe or have life-
threatening consequences.
2. There is no evidence that prolonged prophylaxis has
any advantage over short courses - 24 h. Prolonged
administration may lead to superinfection. Normally in a
clean operation one dose is sufficient. In contaminated
operations three doses are often given.
3. Administer the antibiotic parenterally, immediately
prior to operation to achieve effective tissue levels. If you
give them soon afterwards they do not prevent infection.
If the procedure continues for more than 3-4 h, or if there
212
PREVENTION OF INFECTION IN SURGICAL PRACTICE
19
is excessive blood loss, give a further dose in theatre or
tissue levels may no longer be effective. Acrylic cement
containing gentamicin has been used successfully in joint
replacement surgery.
4. Select antibiotics to cover relevant organisms after
discussion with the microbiologist regarding likely con-
taminants and local resistance patterns. For example, in
orthopaedic surgery the main pathogens are staphylo-
cocci, but in bowel surgery cover is required for anaerobic
and Gram-negative aerobic bowel flora. Work together
with the microbiologist to develop standard policies for
the unit, and follow them strictly when they are in place.
FEEDBACK TO YOU AND THE UNIT
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Using these four strategies, aim to keep your postoper-
ative infection rate to a minimum. Both you and the unit
must keep aware of your infection rates and determine to
keep them comparable with rates in other similar units.
Achieve this by surveillance and infection audit.
Surveillance
This is the systematic collection, collation, analysis and
distribution of data and it has been shown to be valuable
in the prevention of infection. The Study on the Efficacy of
Nosocomial Infection Control (SENIC) was carried out in
the USA over 10 years in the 1970s. A random sample of
1000 patients from each of 338 hospitals was studied and
details about each patient were recorded and analysed. It
was found that infections of the urinary tract were the
most common nosocomial infections but, as already men-
tioned, wound infections were the most costly both finan-
cially and in terms of delayed discharge from hospital.
SENIC data measured intensity of surveillance, control
efforts, policy development and teaching and whether or
not infection rates were fed back confidentially to indi-
vidual surgeons. In hospitals with optimal performance
in all these categories the wound infection rate was 38%
lower. The key factor in this reduction appears to be con-
fidential feedback to individual surgeons. This is known
as the Hawthorne effect.
There are a number of different types of surveillance of
nosocomial infection and no clear consensus regarding the
optimal method. Continuous hospital-wide surveillance
may be expensive and time consuming, while targeted
surveillance may be more practical and cost effective.
Whichever method is employed, it is essential that the
definitions of infection are clearly understood and reliably
applied. Despite the drawbacks, surveillance is useful not
only for feedback but also for identifying changes in epi-
demiology or a rise in infection rates, or for assessing the
effect of implementing new preventive strategies.
Due to the increase in day surgery and shorter hospital
stays, there is evidence suggesting that the majority of
surgical wound infections will present after hospital dis-
charge. The addition of postdischarge surveillance will
therefore provide a more accurate reflection of the true
healthcare-associated infection rate.
Infection audit
Although a record of overall infection rates by surveillance
is the ideal, this may not always be practical, as discussed
above. Clinical audit is a way of reviewing clinical practice
and outcomes and it has also been shown to be useful in
surgical practice. All UK NHS units are required to carry
out audit of their practices. It is important to audit infection
rates. An acceptable standard exists and steps can be taken
to improve rates in the process of closing the audit loop.
Summary
• Do you recognize that postoperative
wound infections cause serious morbidity
to patients and expense to hospitals?
• Can you classify surgical wounds? What
are the infection rates you would expect
for each type of surgical wound?
• Can you outline the main strategies for
minimizing the risk of surgical wound
infection?
• What is the single most important
measure for preventing the spread of
infection between patients?
• What do the terms asepsis, antisepsis,
sterilization and disinfection mean? Name
two antiseptics.
• Can you list the main aseptic precautions
taken in theatre?
• Can you list the major methods of
sterilization and disinfection, and give
examples of when to use them?
• Can you describe the principles of
antimicrobial prophylaxis and give
examples?
• What is the value of surveillance of
hospital-acquired infection to surgical
practice?
213
19
PREPARATIONS FOR SURGERY
References
ACDP, Advisory Committee on Dangerous Pathogens
Spongiform Encephalopathy Advisory Committee 1998
Transmissible spongiform encephalopathy agents: safe
working and the prevention of infection. HMSO, London
Cruse PJE, Foord R 1 980 The epidemiology of wound infection:
a 10-year prospective study of 62 939 wounds. Surgical
Clinics of North America 60: 1
Duckworth G et al 1998 Revised guidelines for the control of
methicillin-resistant Staphylococcus aureus infection in
hospitals. Report of a combined working party of the British
Society for Antimicrobial Chemotherapy the Hospital
Infection Society and the Infection Control Nurses
Association. Journal of Hospital Infection 39: 253-290
Pratt RJ, Pellowe C, Loveday HP et al 2001 Standard principles
for preventing hospital acquired infections. Journal of
Hospital Infection 47S: S21-S37
Further reading
Ayliffe GAJ, Fraise AP, Geddes AM, Mitchell K (eds) 2000
Control oi hospital infection, 4th edn. Arnold, London
Morgan D (ed.) 1995 A code of practice for sterilization of
instruments and control of cross infection (amended). British
Medical Association, London
Philpot-Howard J, Casewell M 1995 Hospital infection control.
Saunders, London
214
The risks to surgeons of
nosocomial virus transmission
D. J. Jeffries, L Ushiro-Lumb
Objectives
Understand the main surgically important
viruses.
Appreciate the sources and methods of
viral transmission.
Recognize how to reduce the risks of
transmission during surgical treatment.
Know what action to take if exposure to
infection has occurred.
INTRODUCTION
Many different viruses have been associated with nosoco-
mial (Greek nosos = disease + komeein = to tend; relating to
hospital) spread and healthcare workers frequently
become infected as part of a hospital outbreak. It may be
difficult to define the extent of an outbreak of a nosocomial
virus infection due to a virus such as influenza or respir-
atory syncytial virus, as there is usually evidence of a par-
allel outbreak in the community and new infections are
likely to be introduced repeatedly by patients, visitors and
staff. Some viruses (e.g. herpes simplex, varicella-zoster
and viral haemorrhagic fever viruses) may be spread to
healthcare workers by close patient contact, while others
may be widely disseminated in a ward or outpatient unit,
e.g. winter vomiting due to small round structured viruses
(SRSVs). The risk of acquiring a nosocomial virus infection
is reduced by the following measures:
1 . Education and awareness of the risks
2. Isolation or cohorting of patients when appropriate
3. Good hygiene and adherence to infection control
procedures
4. Immunization, if vaccines are available
5. Postexposure measures if available.
Close collaboration between microbiologists, virologists
and other healthcare workers ensures that staff are aware
of the risks from individual infected patients and of the
appropriate procedures necessary to control these risks. All
healthcare workers in contact with patients or their samples
are exposed to nosocomial virus infections and, provided
that adequate protective clothing and other facilities are
available, the risk of occupationally acquired infection is
accepted as part of the job. Surgeons are at no greater risk
of acquiring most of the recognized nosocomial virus
infections than any other healthcare worker (for detailed
reviews of specific infections and their control see Breuer &
Jeffries (1990) and Jeffries (1995a)). The nature of your work
exposes you to the risk of infection from blood -borne
viruses, particularly human immunodeficiency virus
(HIV), hepatitis B virus (HBV) and hepatitis C virus
(HCV). All of these viruses may lead to a prolonged infec-
tious carrier state, and demonstration of persistent infection
in a surgeon may lead to the need to change his or her prac-
tice to avoid exposure-prone invasive procedures or, if this
is not possible, it may be necessary to change to another
speciality. There are potentially serious outcomes from
blood-borne virus infections that may be occupationally
acquired; this chapter is therefore focused on these agents.
THEBLOOD-B<^NEJ^IfWSES
Blood-borne viruses posing the highest risk of nosocomial
crossinfection are those associated with a chronic carrier
state, where continuous viral replication leads to persist-
ent viraemia. Currently, the three most important agents
to consider in this setting are HIV, HBV and HCV. Seek
expert advice if other, less common, blood-borne viruses
are being considered.
The main features of HIV and the hepatitis viruses are
presented in the 1995 publication from the Advisory
Committee on Dangerous Pathogens (ACDP), entitled
Protection Against Bloodborne Infections in the Workplace,
and in a review by Jeffries (1997).
Human immunodeficiency viruses (HIV-1,
HIV-2)
The first cases of the acquired immune deficiency syn-
drome (AIDS) were recognized in 1981 and in 1983 a
215
PREPARATIONS FOR SURGERY
retrovirus (HIV-1) was identified and was subsequently
shown to be the causative agent. In 1985, a second human
immunodeficiency virus (HIV-2) was isolated from indi-
viduals from West Africa and this has now spread to other
parts of Africa, India and Europe. The two viruses are
very similar and their modes of spread and clinical effects
are identical, although there is some evidence that disease
progression is slower in HIV-2 infection. In this chapter
the two viruses are referred to collectively as HIV. HIV
contains RNA and during the course of its replication the
genetic material of the viral particle is reverse- transcribed
by an enzyme, reverse transcriptase, into a DNA copy,
which is inserted into the chromosomes of an infected
cell. This integrated package of viral genetic material (or
pro virus) produces new viral particles, which are avail-
able to infect other cells. Thus, following primary infec-
tion with HIV, the virus persists within cells for the life of
the cells and, because of continual transfer to other cells
in the immune system and central nervous system, the
infection persists for the life of the individual. Recent
work indicates that an HIV-infected individual produces
very high levels of virus, 10 9 -10 10 virus particles per day,
and is consequently potentially infectious to others for
life. In health care, the nature of the viral particle, which
is surrounded by a lipid-containing envelope, means that
it is easily destroyed by heat, disinfectants and deter-
gents. At ambient temperatures, however, the virus is pro-
tected from desiccation and may persist in dried blood or
secretions for several days.
The major cellular receptor for HIV is the CD4 antigen
which is present on helper T lymphocytes and cells of the
antigen-presenting series. These are the main target cells
for the virus and gradual depletion of these cells over a
period of years leads to the opportunistic infections and
tumours that are characteristic of AIDS. Potent and
complex combinations of antiretroviral drugs have been
in use for many years now, with an ensuing decline in
morbidity and mortality among individuals who achieve
long-term viral suppression.
Hepatitis B virus (HBV)
Hepatitis B virus is a DNA virus which causes acute hepa-
titis; because of its long incubation period (45-180 days,
mean 75 days) it was previously known as long-incubation
hepatitis (or serum hepatitis). During the acute infection,
and in carriers of HBV, viral particles released from the
liver are present in the circulation. The surface coating of
the particles is present in excess and this material, hepa-
titis B surface antigen (HBsAg), is identified by serological
tests as the main indicator of active infection. A second
antigen, HBeAg, which is derived from core particles of
the virus present in the liver, indicates continuing activity
of the virus in the liver, and the presence of HBeAg in the
blood correlates with high levels of infectivity. Note,
however, that precore mutants of HBV exist, which are
unable to express HBeAg but continue to produce infec-
tious viral particles. Individuals carrying such HBV vari-
ants may have high levels of viraemia despite undetectable
serum HBeAg, which ultimately translate into higher
levels of infectivity than previously thought. The implica-
tions of this HBV variant in the healthcare setting will be
further addressed when discussing the infected healthcare
worker.
As with all types of viral hepatitis, the degree of
illness produced is variable and ranges in different indi-
viduals from asymptomatic infection to acute hepatic
failure. The immune response is a major factor in
determining the severity of disease. In the immunologi-
cally immature or immunocompromised, asymptomatic
infections are common, but the risks of proceeding to
long-term carriage of the virus are high. The long-term
carrier rate following neonatal infection is >90%, in chil-
dren aged 1-10 years it is 23%, and in adults 5% or less
become carriers. This high rate of persistence following
infection in early life largely explains the estimated
250-300 million carriers in the world, the majority of
whom are in resource-deprived countries, where 15-20%
of the population may be infected.
The carrier of HBV presents a potential risk of hori-
zontal transmission to others, predominantly via sexual
intercourse and blood transfer. The HBV-positive mother
is also likely to infect her baby during delivery, with the
highest risk amongst HBeAg-positive carriers (up to
90%). Vertical transmission is in fact a very important
route of HBV spread in parts of the world where the virus
is highly endemic.
Persistent replication of HBV in the liver of HbeAg-
positive carriers carries a risk of progressive liver
damage, leading to chronic active hepatitis, cirrhosis and
an increased risk of hepatocellular carcinoma.
Hepatitis C virus (HCV)
Following the identification of HBV, the continued occur-
rence of post-transfusion hepatitis led to the realization
that there were other blood-borne hepatitis viruses
(termed non-A, non-B hepatitis). The RNA virus, HCV,
is now recognized as the major cause of non-A, non-B
hepatitis, with an estimated 170 million people infected
worldwide. Hepatitis C is predominantly blood borne
and infection is common in injecting drug users and
recipients of unscreened blood and /or blood products.
The acute phase of HCV infection is usually asymp-
tomatic and only approximately 10% of individuals have
overt hepatitis. Following primary infection, however,
the majority (about 80%) proceed to become persistent
carriers of the virus and, as with HBV infection, there is
216
THE RISKS TO SURGEONS OF NOSOCOMIAL VIRUS TRANSMISSION
20
a long-term risk of chronic liver disease with cirrhosis
(10-30%) and hepatocellular carcinoma. In the industri-
alized world, chronic HCV infection is the leading cause
of chronic liver disease and the most common indication
for liver transplant.
SOURCES OF INFECTION
As the term implies, the major blood -borne viruses, HIV,
HBV and HCV, are found predominantly in the circula-
tion and most occupational infections occur as a result of
exposure to blood. Other body fluids may contain infec-
tious virus, however, and these are listed in Table 20.1.
Percutaneous inoculation is the major route of infection in
health care; there is no evidence of transmission of any of
the common blood-borne viruses by the airborne route or
from occupational or social contact that does not involve
body fluid exposure.
RISKS OF INFECTION
Transmission of blood-borne viruses from patient to
healthcare worker most commonly occurs following per-
cutaneous exposure to infected blood through a 'sharps'
injury. Although transmission may also result from con-
tamination of broken skin, or of mucous membranes of
the eyes or mouth, the risks are much lower.
HIV
The overall risk of acquiring HIV following a single per-
cutaneous inoculation with HIV-infected blood is approx-
imately 0.36% (1 in 275). The results of a case-control
study of 31 healthcare workers infected occupationally,
compared with 679 control subjects, identified several
factors that affected the risks of percutaneous transmis-
sion of HIV (Centers for Disease Control 1988). These are
listed in Table 20.2. Note from the table that, in this
case-control study, the use of the antiviral drug AZT
reduced the transmission rate by 80%. This will be
returned to later. The risk of acquiring HIV from mucous
membrane or conjunctival exposure to blood from
infected individuals is lower than from percutaneous
inoculation. One seroconversion was reported on follow
up of 1107 exposures (Jeffries 1995b).
HBV
Hepatitis B immunization has dramatically altered the
level of risk to surgeons and other healthcare workers.
Before the introduction of safe and potent HBV vaccines
and subsequent checks of immune status, the risk of infec-
tion could be as high as 30% after percutaneous injury
involving the blood of an HbeAg-positive patient.
Transmission of HBV has also been associated with
mucous membrane exposure to blood and with bites from
HBV-infected patients but the risk of infection from these
routes has not been quantified.
HCV
The risk of percutaneous transmission of HCV has not been
clearly defined and rates of 0-10% have been reported. In
a small study of 68 healthcare workers in Japan, who sus-
tained percutaneous exposure to the blood of HCV RNA-
positive patients with chronic renal failure or HCV-related
liver disease, seven (10%) developed markers of infection.
In a survey of 3267 orthopaedic surgeons in the USA, HCV
antibodies were present in 0.8%. The antibody prevalence
increased from 0% in the 20-29 year age group to 1.4% in
those over 60 years. For comparison, 12% had evidence of
past or current HBV infection (ranging from 2.9% in the
20-29 year age group to 26% in those 60+) and two sur-
geons were HIV positive (both had other risk factors apart
from surgery).
Table 20.1 Body -fluids, etc. that should be
handled with the same precautions as blood
2.
3.
CSF
Semen
Vaginal secretions
Breast milk
Amniotic fluid
Peritoneal fluid
Pleural fluid
Pericardial fluid
Synovial fluid
Any other body fluid containing visible blood
Unfixed tissues and organs
Table 20,2 Factors affecting percutaneous
transmission of HIV during occupational exposure
Factor
Odds ratio* 95% CI
Deep injury (intramuscular)
16.1
6.1-44.6
Visible blood on device
52
1.8-17.7
Needle used in a blood vessel
S.1
1.9-14.8
Source patient with AIDS
6.4
2.2-18.9
AZT prophylaxis used
0.2
0.1-0.6
♦Significant at p < 0.01.
Adapted from Centers for Disease Control (1988).
217
PREPARATIONS FOR SURGERY
REDUCING THE JMSKSJW
General measures - universal precautions
It is neither cost effective nor reliable to embark on
routine screening of patients for blood-borne viruses.
The marker tests for infectivity, HIV and HCV antibodies
and HBsAg become positive up to 12 weeks, 26 weeks
and 26 weeks, respectively, after infection and a patient
may be highly infectious before positivity is demon-
strated. Similarly, it is unreliable to attempt to identify
carriers of the viruses by designation of 'risk groups'.
Although the blood-borne viruses HIV and HCV were
originally associated with homosexuality and drug use,
the spread of infection outside of perceived risk groups,
and control of infection in those previously perceived
to be in risk groups by education, needle exchange
schemes, etc., means that 'risky activity' by anyone
should raise the suspicion of possible infection. Faced
with the ever present risk of occupational infection, you
should adopt a policy of 'universal precautions' with
regard to carrying out procedures with a risk of contact
with high risk body fluids and tissues (see Table 20.1).
The basis and procedure of using universal precautions
was presented by the Centers for Disease Control (1987,
1988, 1991) and by the UK Health Departments (1990,
1998). As percutaneous inoculation is the major route of
infection, take care when handling sharp instruments. In
some studies, approximately 40% of inoculation injuries
of staff have occurred during attempts to resheathe
needles.
Key points
• Always pass sharp instruments to others
through the vehicle of a rigid container, never
directly.
• Do not attempt to resheath needles unless
there is a resheathing device available. Discard
them into a 'sharps' container.
Do not leave suture needles and scalpels on trays for
others to clear away. Cover cuts and abrasions with
waterproof dressings and wear disposable gloves if there
is a risk of contamination of your hands with blood. Wear
protective eyewear and a mask if there is likely to be any
splashing with blood or other body fluids.
It is possible to produce guidelines for the use of pro-
tective clothing on the basis of an assessment of likely
exposure to blood (Table 20.3).
Attend to blood spillage on to a surface promptly, by
first covering it with disposable towels, and apply a suit-
able disinfectant, such as sodium hypochlorite (10 000
parts per million available chlorine), in accordance to
local infection control guidelines.
Immune prophylaxis
While neither passive nor active prophylaxis is available
for HIV and HCV, HBV infection is preventable by immu-
nization with the current, safe, genetically-engineered
Table 203 Categorization of procedures according to risk of exposure to blood
Category
A(i) Contact likely:
risk of uncontrolled
bleedrng
A(ii) Contact probable;
splattering unlikely
A(iii) Low likelihood of
blood contact
B No risk of blood contact
Examples of procedures
Major surgery
Gynaecology
Obstetrics
Intra-arterial puncture
Insertion/removal of intravenous/
intraarterial lines
Dentistry
i.m. r i.d., s,c. injections
Most ward/clinic work
Protective measures
Full range of protective clothing (gloves,
water-repellent gown and apron,
protective headwear, mask,
protective eyewear, protective footwear}
Gloves to be worn
Masks/protective eyewear to be available
Gloves available
None necessary
Adapted from UK Health Departments {1990).
218
THE RISKS TO SURGEONS OF NOSOCOMIAL VIRUS TRANSMISSION
20
vaccines. All staff likely to be exposed to blood, tissues or
other body fluids in the course of their work should be
immunized and their antibody levels should then be
checked to ensure that they have developed protective
immunity. If response to the vaccine is inadequate, the
healthcare worker's hepatitis B status should be investi-
gated to exclude current or past HBV infection. Those
who are susceptible to HBV and fail to mount an antibody
response to the vaccine must be made aware that they are
non-responders and, in the event of exposure to known or
suspected HBV-positive blood, they should be offered
passive protection with HBV immunoglobulin (HBIG).
Reducing blood exposure of you and your
patient during operation
In an observational study by Tokars et al (1992), the rate of
inoculation injury was recorded during the course of dif-
ferent types of surgical operation. Percutaneous injury rates
to the main operator per 100 procedures were 4 for
orthopaedics, 8 for general surgery, 9 for coronary artery
bypass grafting, 17 for gastrectomy and 21 for vaginal hys-
terectomy Inspection of gloves after operation has revealed
a perforation rate for single glove use of 11-54% (Church &
Sanderson 1980, Brough et al 1988, Maffulli et al 1989, Smith
& Grant 1990, Palmer & Rickett 1992). The wearing of two
pairs of surgical gloves has been reported to result in per-
foration of the inner glove in 2% of operations (Matta et al
1988). Penetration of the glove material by a sharp instru-
ment or needle has a significant wiping effect and this
reduces the volume of blood and amount of virus trans-
ferred. Studies using a paper prefilter model in vitro and an
ex vivo porcine tissue model demonstrated a reduction of
blood transfer of 46-86%, depending on whether a solid or
hollow needle was used and on the gauge of the latter
(Mast et al 1993). Thus, although standard disposable latex
gloves offer no protection against needle penetration, this
evidence of reduction of exposure to blood provides strong
support for the use of gloves, even in simple procedures
such as venepuncture, if there is a risk of injury to the oper-
ator, for example in the case of an uncooperative patient.
A number of aspects of surgical technique are worthy
of appraisal in the interests of reducing the risk of percu-
taneous injury.
• Favour the 'hands-free' technique, in which the
same sharp instrument is not touched by more
than one person at the same time.
The need for care in passing instruments to others has
already been stressed. Needles, scalpels and other sharp
instruments should not be left in the operating field. Have
them removed promptly by the scrub nurse after they
have been deposited in a neutral zone, such as a tray or
kidney dish. Use instruments rather than fingers for
retraction and holding tissues during suturing. Remove
scalpel blades from handles with instruments and direct
all needles and sharp instruments away from your own
non-dominant, or your assistant's hand. Remove suture
needles before tying sutures, or use instruments rather
than fingers for tying.
In addition to the discipline of carrying out surgical
techniques, in appropriate circumstances consider using
alternative equipment. Electrocautery, blunt-tipped
needles and stapling devices may reduce the need for
sharp instruments and needles. Avoid using sharp clips
for surgical drapes. Prefer blunt clips or disposable
drapes incorporating self-adhesive film. Employ scalpels
which are disposable, have a blade release device or
retractable blades, to remove the risk of injuries associ-
ated with assembly or disassembly of these instruments.
The risk of contact with infected blood varies depend-
ing on the local prevalence of infections and the nature of
the patient population. With the current distribution of
blood -borne viruses, however, all operating theatre staff
are exposed from time to time. The decision to introduce
double-gloving for all surgical procedures may depend
on a local risk assessment, but other measures to reduce
exposure to blood and other body fluids can be applied
to all operative procedures.
Postexposure measures
Key points
Whenever possible have one person only
working in an open wound or body cavity at
any one time.
Key point
• As soon as possible after percutaneous
inoculation or, in the case of operative surgery,
as soon as the patient is stable and can be left
to the care of others, wash the site of injury
liberally with soap and water.
Avoid scrubbing, encourage bleeding. Do not use anti-
septic preparations, as the effect of these on local
defences is unknown. Wash out splashes into the eye or
mouth by irrigating with copious volumes of water.
219
20
PREPARATIONS FOR SURGERY
Complete an incident form and contact the occupational
health department or another doctor designated with the
responsibility of caring for staff, as specified in the local
guidelines.
Key point
• Seek advice at once; if postexposure
prophylactic drugs for HIV are to be
considered, they should be started without
delay, and ideally within 1 h of exposure.
It is normal practice to take a blood sample from the
staff member at this time as the stored serum can then be
used as a baseline for further testing. Laboratory testing
of the source patient, after pretest discussion and obtain-
ing fully informed consent will aid further management
by clarifying the risks, if any, of exposure to blood-borne
viruses.
Key point
• Decisions on postexposure prophylaxis should
not await results of testing the source patient.
Immediate assessment of risk of transmission
must include the source patient's history and
the type and severity of the exposure.
HIV
Guidelines for the use of postexposure chemoprophyl-
axis to prevent HIV infection of healthcare workers
were issued in the UK in June 1997 (UK Health
Departments 1997). Postexposure prophylaxis is recom-
mended when there has been significant exposure to
material known, or strongly suspected, to be infected
with HIV. Significant routes of exposure are percuta-
neous inoculation, exposure of broken skin or contact
with mucous membranes, including the eye, and high
risk material (listed in Table 20.1). As in equivalent
guidelines issued in the USA, the first-line drugs for
postexposure prophylaxis are currently combined
zidovudine (AZT) 300 mg and lamivudine (3TC) 150 mg
b.d., and nelfinavir 1250 mg b.d. Treatment should start
as soon as possible, ideally within 1 h of exposure, and
should be continued for 1 month. A negative test for HIV
antibody 6 months after the exposure confirms the
absence of occupationally acquired infection.
HBV
If the source patient is known or suspected to be an HBV
carrier, the prophylactic regimen will depend on the
immune status of the healthcare worker. Those who have
never had vaccine should receive hepatitis B immuno-
globulin (HBIG) within 48 h of exposure and a course of
hepatitis B vaccination should be started as soon as possi-
ble. In those who have been vaccinated, the recommenda-
tion of the occupational health adviser is likely to depend
on the record of the person's antibody response. If there is
a recorded antibody response of more than 100 min ml 1
within the previous year, no further action is necessary. If
the person's blood has not been tested within the year, or
if a lower titre was recorded, a booster dose of vaccine fol-
lowed by retesting of antibody status may be necessary.
Healthcare workers who have failed in the past to respond
to the vaccine should be offered protection with HBIG.
HCV
There is currently no prophylaxis for HCV and follow up
consists of monitoring liver function and testing for anti-
HCV antibodies and HCV RNA. There is, however,
growing evidence to suggest that commencement of
antiviral therapy with interferon-a during the acute phase
of HCV infection can prevent chronic carriage (Jaeckel et al
2001), and occupational exposure to HCV is potentially
the ideal indication for interventions of this nature.
INFECTED HEALTHCARE WORKERS
>:££i&=&^-&^^
••^^^^^^^^m^^/^^^\
Guidelines issued by the General Medical Council,
General Dental Council and the United Kingdom Central
Coordinating Committee for Nurses, Midwives and
Health Visitors (UKCCC) stress the importance of health-
care workers who consider that they have been at risk of
infection with HBV or HIV seeking appropriate pretest
discussion and testing. If found to be infected, they have
a responsibility to be under regular medical supervision.
Guidelines issued in the UK recommend that those who
are infected with HIV or who are 'high infectivity'
(HBeAg) carriers of HBV should not perform exposure-
prone invasive procedures (UK Health Departments 1993,
1994). Exposure-prone procedures are defined as:
Those where there is a risk that injury to the worker
may result in the exposure of the patient's open
tissues to the blood of the worker. These procedures
include those where the worker's gloved hands may
be in contact with sharp instruments, needle tips or
sharp tissues (spicules of bone or teeth) inside a
220
THE RISKS TO SURGEONS OF NOSOCOMIAL VIRUS TRANSMISSION
20
patient's body cavity, wound or confined anatomical
space where the hands or fingertips may not be
visible at all times.
In the UK, until recently and according to the above
guidelines, there were no practice restrictions to HBV car-
riers without detectable HBeAg, unless transmission to
patients had been demonstrated. In the light of accumu-
lated evidence of transmission of HBV from HBeAg-
negative carrier surgeons (harbouring precore variants of
HBV) to their patients and better knowledge of levels of
viraemia associated with such transmission events (The
Incident Investigation Teams 1997), new guidelines
became available in 2000. The Department of Health
now recommends additional molecular-based tests for
HBeAg-negative carriers who perform exposure-prone
procedures (UK Health Departments 2000). Healthcare
workers whose HBV viral load exceeds 10 3 genome
equivalents per millilitre should not perform exposure-
prone procedures. Those with viral loads below 10 3 are
not restricted from any areas of work but should be
retested at 12 monthly intervals.
For some surgeons and other healthcare workers, con-
fidential discussion between the person concerned and his
or her health adviser may lead to minor changes in prac-
tice that would allow work to continue with the avoidance
of exposure-prone procedures. If there is any doubt, advice
should be sought from a specialist occupational health
physician, who may, in turn, wish to present the situation
anonymously to the UK Advisory Panel for Health Care
Workers Infected with Bloodborne Viruses (UKAP).
Some specialities, e.g. dentistry, are concerned almost
totally with activities that are, by definition, exposure
prone. For HIV, HbeAg-positive and HBeAg-negative car-
riers with high viral load (as defined above) working in
such specialities, the only option in the UK is for retrain-
ing in another speciality which does not require the use
of exposure-prone procedures.
No recommendations have yet been issued in the UK for
healthcare workers found to be carriers of HCV unless they
have been demonstrated to have transmitted their virus to
a patient, in which case exclusion from exposure-prone
procedures has been advised. Nevertheless, following
several reports of transmission of HCV from healthcare
workers to patients, the Advisory Group on Hepatitis has
proposed new guidelines. One of the likely upcoming rec-
ommendations is that healthcare workers who are found to
have been infected with HCV and who are involved in
exposure-prone procedures will have to be tested for HCV
RNA. Demonstration of viraemia (detectable RNA) will
preclude the individual from performing exposure-prone
procedures, until sustained response to antiviral therapy is
documented. A consultation exercise has recently taken
place and implementation of the new guidelines is awaited.
CONCLUSIONS
%^?^<r^^^^^^^^^:.
You will continue to be at risk, albeit small, of acquiring
blood-borne viruses from your patients. The level of risk
varies depending on the prevalence of viruses in the local
population. Adoption of universal precautions and careful
attention to operative technique reduces the risks to the
operator and other staff to a minimum. There is consider-
able cause for concern if you are expected to operate in
situations where, for lack of resources, there is inadequate
provision of protective clothing, such as impermeable
gowns and disposable gloves, and hepatitis B vaccine. A
significant exposure to the blood of a patient causes con-
siderable anxiety for a period of up to 6 months and until
laboratory tests confirm negativity. There is no reason for
you to avoid exposure-prone procedures during this
period, providing you are aware that there is a possibility
of infection developing and provided that you practise a
high standard of infection control. It may be necessary,
however, for your medical adviser to recommend lifestyle
changes, such as condom usage for sexual intercourse, and
avoidance of donating blood, semen, etc. to prevent trans-
mission to others by non-occupational routes. In the UK,
as described earlier, guidelines for HIV- and HBV (HBeAg-
positive, HBeAg-negative with high viral load)-infected
healthcare workers advise strongly against participation in
exposure-prone procedures. This is likely to be extended,
in the very near future, to HCV-infected individuals who
are shown to be viraemic This approach is not adopted in
many other countries where either no restriction is placed
on clinical practice or exposure-prone procedures can con-
tinue providing the patient is informed of the situation.
Summary
• Do you recognize the procedures that
raise the risks of viral transmission?
• Will you determine to take precautions on
behalf of yourself, your patients and your
colleagues?
• Will you resolve not to abandon universal
precautions in emergency circumstances?
• Do you know what to do if an incident has
exposed you or anyone else to the risk of
contamination?
221
20 '
PREPARATIONS FOR SURGERY
References
Advisory Committee on Dangerous Pathogens (ACDP) 1995
Protection against bloodborne viruses in the workplace: HIV
and hepatitis. HMSO, London
Breuer J, Jeffries DJ 1990 Control of viral infections in hospital.
Journal of Hospital Infection 16: 191-221
Brough SJ, Hunt TM, Barrie WM 1988 Surgical glove
perforation. British Journal of Surgery 75: 317
Centers for Disease Control 1987 Recommendations for
prevention of HIV transmission in health care settings.
Morbidity and Mortality Weekly Report 36(2S): 1S-18S
Centers for Disease Control 1988 Update: universal precautions
for prevention of transmission of human immunodeficiency
virus, hepatitis B virus, and other bloodborne pathogens in
health care settings. Morbidity and Mortality Weekly Report
37: 377-388
Centers for Disease Control 1991. Recommendations for
preventing transmission of human immunodeficiency virus
and hepatitis B virus to patients during exposure prone
invasive procedures. Morbidity and Mortality Weekly Report
40(RR-S): 1-9
Church J, Sanderson P 1 980 Surgical glove punctures. Journal of
Hospital Infection 1 : 84
Jaeckel E, Cornberg M, Wedemeyer H et al 2001 Treatment of
acute hepatitis C with interferon alpha 2b. New England
Journal of Medicine 345: 1452-1457
Jeffries DJ 1995a Viral hazards to and from health care workers.
Journal of Hospital Infection 30(suppl.): 140-155
Jeffries DJ 1995b Surgery and bloodborne viruses. PHLS
Microbiology Digest 12: 150-154
Jeffries DJ 1997 Viral agents of bloodborne infections. In: Collins
CH, Kennedy DA (eds) Occupational bloodborne infections.
CAB International, Wellingford, pp 1-16
Maffulli N, Capasso G, Testa V 1989 Glove perforation in
elective orthopaedic surgery. Acta Orthopaedica Scandinavica
60: 565-566
Mast ST, Woolwine JD, Gerberding JL 1993 Efficacy of gloves in
reducing blood volumes transferred during simulated
needlestick injury. Journal of Infectious Diseases 168:
1589-1592
Matta H, Thompson AM, Rainey ]B 1988 Does wearing two
pairs of gloves protect operating theatre staff from skin
contamination? BMJ 297: 597-598
Palmer JD, Rickett JWS 1992 The mechanisms and risks of
surgical glove perforation, journal of Hospital Infection
22: 279-286
Smith JR, Grant JM 1990 The incidence of glove puncture
during caesarean section. Journal of Obstetrics and
Gynaecology 10: 317-318
The Incident Investigation Teams and Others 1997 Transmission
of hepatitis B to patients from four infected surgeons without
hepatitis B e antigen. New England Journal of Medicine 336:
178-185
Tokars JL, Bell DM, Culver DH et al 1992 Percutaneous
injuries during surgical procedures. JAMA 267:
2899-2904
UK Health Departments 1990 Guidance for clinical health care
workers. Protection against infection with HIV and hepatitis
viruses. Recommendations of the Expert Advisory Group on
AIDS. HMSO, London
UK Health Departments 1993 Protecting health care workers
and patients from hepatitis B. Department of Health,
London
UK Health Departments 1994 AIDS /HIV-infected health care
workers: guidance on the management of infected health care
workers. Department of Health, London
UK Health Departments 1997 Guidelines on post-exposure
prophylaxis for health care workers exposed to HIV.
Department of Health, London
UK Health Departments 1998 Guidance for clinical health care
workers. Protection against infection with bloodborne
viruses. Department of Health, London
UK Health Departments 2000 Hepatitis B infected health
care workers. HSC 2000/020. Department of Health,
London
222
SECTION 4
223
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Good surgical practice
/?. M. Kirk, J, Dawson
Objectives
Understand and accept your
responsibilities.
Commit yourself to the care and
well-being of your patients and preserve
their confidentiality.
Work within your capabilities.
Allocate your time sensibly.
Keep good notes.
Be a good team player.
Preserve your integrity.
Try not to be a man of success, but try to be a man of
value. Albert Einstein
If you are going to worry about this in bed tonight,
Doc, get it right now.'
The peerless London surgeon Norman Tanner never
said this; his every action proclaimed it. This chapter
was previously contributed by the late John Dawson,
a good friend, dedicated teacher, setter of high stan-
dards, and, like me, privileged to train with Norman
Tanner.
INTRODUCTION
^^5&S^:^S^
You must behave competently and honourably towards
your patients, colleagues and society, and maintain open-
ness to inspection. Aim to achieve high standards in all
aspects of your life. Incompetence or dishonesty detected
in one area implies similar failings in other areas.
In the past we were privileged to satisfy only our own
consciences. At the end of each day we hoped to be able
to say, T may have made errors but not from want of
trying to achieve the best for my patients and those with
whom I have worked/ Most of us relied on this and
resolved ourselves, without the need to be exhorted by
others, to do better when we fell below the standards to
which we aspired. However, because our profession
sometimes failed to weed out the few identified as incom-
petent, lazy or dishonest, we have lost some of the trust
we formerly commanded. Society regards us more criti-
cally than formerly, and we need to help restore our
former high reputation.
CLINICAL COMPETENCE
1. This is the foundation of all your professionalism.
You need knowledge, and skill in taking a history, exam-
ining patients, making decisions and acting upon them.
You constantly need to improve them by following your
results to assess the outcomes, in the hope of learning
how to improve them.
2. Your competence is most under strain in emer-
gency circumstances. When performing electively you
can obey the rules. In an emergency you often need to
decide in an instant whether you should or should not
conform. There are circumstances when you need to
interpret rules sensibly, as they are made to cover most
but not all situations. The heroic, legless, Second World
War airman, Douglas Bader, declared, "Rules are for the
guidance of wise men, and the blind obedience of fools/
But remember that you may be called upon to justify
your actions.
3. Competence is not a 'once-and-for-all' achievement.
It is a continuous process of critically noting your perfor-
mance in all aspects, identifying your failures and learn-
ing from them. It depends upon meeting, watching and
listening to your colleagues, attending courses and criti-
cally reading the literature.
Key points
Surgical improvement does not develop by
merely working hard.
Stand back, identify weaknesses, search for
improvements and implement them.
225
21
OPERATION
PATIENT TRUST
A vital characteristic for a medical attendant is to be trust-
worthy. If we are trusted, our patients are open with us,
allow us to examine them and perform procedures that
may be difficult or impossible without their cooperation.
They will not tell us^ the often private information we
need to know, unless they trust us.
To gain patients' trust we need to:
1. Communicate with them (see Ch. 47). This implies
not just giving them information but also being
receptive to the verbal and non-verbal information
they transmit.
2. Involve them in the decision making (see Ch. 13) so
they can give informed consent to what is agreed
upon (see Ch. 14). Accede to a request for a second
opinion; it is not a blow to your dignity.
3. Be open with them in admitting ignorance, in
admitting that there has been a failure in managing
them, in admitting our own error of judgement or
practice. Whenever we admit to a failure we should
always clearly state, and be prepared to discuss,
what we intend to do to correct it.
4. Respond to the patients' anxieties regarding their
outlook, discomfort or pain, complications, loss of
function and loss of dignity. Saying 'Sorry/ is not an
admission of guilt but an expression of sympathy.
5. Provided the patients agree, inform and discuss with
relatives at all stages what is happening, what is
proposed and what is the likely outlook. Relatives
often exert great influence in supporting and
reassuring your patients. Conversely, they may
undermine patients' trust in their recovery and in
your management.
6. Protect patients' confidentiality and preserve their
dignity. Illness attacks not only their bodies but also
their morale; they may wish to keep their health
problems private.
PROFESSIONALISM
1. Strictly speaking surgeons (Greek cheir = hand +
ergon = work; hence, manual workers) are not profes-
sionals - but we now consider ourselves to be 'physicians
who perform operations'. This is not strictly correct;
many medical specialists perform skilful manipulations
(Latin mantis = hand + plere - to fill). 'Professionalism'
carries the connotation of performing competently and
autonomously without the need to be directed, in order
to produce a satisfactory result.
2. The four most important qualities of a professional
surgeon, which are often overlooked because they are not
subject to objective assessment, are the four 'Cs' -
common sense, competence, commitment and compas-
sion. When you take up a task, ensure that you apply
these qualities to achieve the best possible result.
3. Maintain your professionalism in whatever circum-
stances you practise:
a. Respect the fact that some patients have different
beliefs from you and may reject aspects of your proffered
treatment for religious or other reasons. Jehovah's
Witnesses, for example, may reject blood transfusion.
Because many beliefs are subject to personal interpreta-
tion, make sure you know what exactly are the implica-
tions when patients declare their adherence to a particular
sect.
b. In an emergency your professional judgement is put
under increased strain (see Ch. 13). You may be called on
to carry out procedures at the edge of, or beyond, your
capabilities. As you make your decision and act upon it,
recognize that you will need to justify it to your patient,
your peers and to your own conscience.
c. If you participate in specialist procedures, such as
organ transplantation, adhere strictly to the legal and
ethical requirements.
d. If you are present at an armed conflict, be aware that
your actions may be under intense scrutiny to detect
whether you are favouring one side over the other. Treat
all patients who are presented to you on an equal basis
and to the highest possible standard.
e. Treat prisoners as you would anyone else. Refuse to
participate in any action that may cause physical or
mental suffering.
f. If you work in another country, avoid offending
against local laws and customs. Do not, however, allow
your standards to fall, even though you may not
have all the facilities you would normally have at your
command.
g. Do not perform any operations that conflict with
your own moral values.
4. We are all in part the products of our teachers. One
of the privileges of being in the profession of surgery is
that we are always trainees and at the same time we can
all be teachers. Pass on to your juniors the ideas, the
wisdom, the skills that you have acquired. With permis-
sion from your seniors, delegate procedures in which you
are skilled, while you teach and supervise your juniors. In
the past, too much unsupervised responsibility was dele-
gated to trainees, summed up in the aphorism, 'See one,
do one, teach one.' This is no longer tolerated.
5. Preparing to teach forces you to be ready to justify
statements that you make, and actions you take. It is one
of the most effective ways of learning for yourself and
honing your skills. Many procedures are best taught by
example, copied - often unconsciously - by the trainee,
not by reading or listening.
226
GOOD SURGICAL PRACTICE
21
RECORDS
?s$vy&^^ ^hs;
&^^^ 9 *^&PK
1. We like to be considered as people of action, rather
than reporters of action. If we are to be accountable,
however, we must keep accurate records (see Ch. 48). It
is not enough that you have acted correctly. Others,
wishing to inspect your actions, must be able to confirm
them.
2. Write or dictate records as soon as possible after the
event. Ensure they are comprehensive, comprehensible,
dated and signed so they are attributable to you. Record
not only the positive findings but also the negative ones:
if you do not mention these it could be assumed that you
did not examine for them. Do not use abbreviations that
can be misconstrued: spell out 'Left/ 'Right/ Jargon that
you use may be incomprehensible or misconstrued by
others.
3. There are no more important records than those
describing surgical operations. Detail what you found,
what you sought but did not find. Describe all the proce-
dures, any difficulties and the situation at the end of the
operation. It is vital to recount what must be done in the
immediate postoperative period regarding monitoring,
circulatory and respiratory management, pain control,
drug treatment, and any special instructions you wish to
be followed. Make sure you inform those who look after
the patient under what circumstances you wish to be
informed.
HUBRIS
'^<£$&&^g&
1 . I have deliberately used this unusual word (Greek
= excessive pride). Although it is reasonable to take
pride in accomplishment, overweening pride is a dan-
gerous emotion. We are all fallible. No one can claim to
make the right decisions and perform perfectly every
time. Protecting your pride is a dangerous path on
which to embark; each step racks up the likelihood of
disaster.
2. Do not be too proud to call for - and accept - help
or advice, or the taking over of your patient by someone
who is more capable than you are.
3. Do not be too proud to admit error to your patients,
your peers and, particularly, yourself.
TIME MANAGEMENT
1. This is often self-management. You rarely have but
a single commitment. More frequently you have many.
You must rank your commitments and review the
ranking at intervals, as a previously non-urgent problem
may suddenly become urgent.
2. Except in an emergency, ensure that you fully com-
plete one task before leaving it to start another. It is
ineffective and unprofessional to leave a trail of almost
completed tasks. However, be aware that acute situations
develop so that you are called urgently. Although there is
a temptation to complete the present task, in some cases
you must abandon whatever you are doing and return to
it later.
Key point
• React to changed circumstances. Compare the
urgency of competing demands, decide the
correct action and carry it out.
3. Some people apply pressure on you for immediate
action, against your better judgement. If other problems
are more urgent, you may need to refuse. Be as diplomatic
as possible but do not make undeliverable promises.
TEAM MEMBERSHIP
:■: ^>^r&^:^'4i^i^^^^^
1. In the past, surgeons were undisputed team leaders
and decision makers. We were depicted as the courageous
pioneers, sometimes succeeding, sometimes failing to
cure or relieve our patients.
2. The mores (Latin moris = custom) have changed dra-
matically. No one is immune from criticism or from com-
parison of their results with those of their peers (Latin par,
paris - equal). We no longer work as individuals. For
example, anaesthetists who initially worked under orders
from surgeons now unequivocally take charge of the
patient's well-being, freeing us to concentrate on the deci-
sions and technical problems of the operation. The spe-
cialists in imaging and other diagnostic aids, assistants,
specialist and general nurses, physiotherapists, techni-
cians and many others form part of the team, each one
having an input into the general decisions and necessary
actions. The best teams work in harmony, with each
member feeling important, respected and therefore loyal
to the team.
3. The change in attitude is fundamental. In the past an
opinion carried weight according to the distinction and
seniority of the proposer. Now each opinion is, or should
be, judged on the merits of its logic and the evidence
offered to support it.
4. Being a good team member offers you many bene-
fits. Your colleagues will celebrate your successes and
sympathize with your failures. When you need help they
will respond. If you are a poor team member you may not
always rely on these important supports, or they may be
227
OPERATION
given reluctantly. We all need encouragement when our
self-esteem is reduced, as inevitably happens from time to
time when a series of things go wrong.
5. Team membership, however, places you in circum-
stances of conflicting loyalties. Although you wish to
support and protect your colleagues, this must not take
precedence over your responsibilities to patients and
society. If any of your colleagues fail in their duties, or
are physically or mentally sick and present a risk to
patients, you must encourage them to take appropriate
treatment and inform appropriate authorities if they do
not.
TEACHJI|G^AND
1 . Take every opportunity to pass on your knowledge
to your trainees. Of course, it is not your own knowledge.
It is mainly acquired from your own trainers and you are
an intermediary. It is not just the facts that you transmit
but the unconscious influence you have on their attitude,
if your behaviour and performance are to the highest
standards you can achieve.
2. Always try to give those junior to you time to
express their opinions first, to give them the opportunity
and challenge of making and preparing to act on deci-
sions, as they will need to do when they become
autonomous consultants.
3. It is often difficult to delegate responsibility to
others, but monitored, progressive delegation is a vital
process of preparing for tomorrow's consultants.
Key point
As a surgeon in training, always seek your
chief's approval before delegating
responsibility or practical procedures.
4. You may find it even more difficult to delegate prac-
tical procedures that require skilful accomplishment.
Again, first delegate simple procedures under direct
observation and progress to more complex ones with less
obvious - more discreet - monitoring.
INTEGRITY
--3&3&&!i*:¥*^^^
1. Place a high value on your probity and integrity.
Patients, colleagues and the general public will usually
forgive you for mistakes. We all, inevitably, make them
from time to time, as we work in a field in which we do
not, and cannot, know all the facts in the present state of
our knowledge. They will not so easily forgive deceit,
dishonesty or duplicity.
2. Moreover, once you have been found guilty of
discreditable behaviour you have forfeited your good
character and will never again be fully trusted.
3. As a professional, be honest in publishing your clin-
ical results, your research techniques and the findings.
4. You cannot separate your professional from your
private reputation. A surgeon who unfairly blames a col-
league for his or her own mistake, falsifies a legal report,
claims money illegally or is corrupt in any matter has a
stained character.
5. Avoid conflicts of interest. Avoid accepting gifts,
favours, hospitality or anything that puts pressure on
you. You must be able to make decisions on clinical neces-
sity, not for any other reasons.
6. Financial dishonesty arouses particular scorn. Take
exceptional care not to take or accept any money to
which you are not entitled or which puts you under an
obligation, which will undoubtedly subsequently be
called in.
HEALTH..
1. In addition to the other qualities required, the prac-
tice of surgery demands outstanding stamina. It is neces-
sary to respond to a sudden emergency at the end of a
long and busy routine day, or to a sudden disaster near
the end of an arduous major operation.
2. Avoid risking your health from accidents and infec-
tions, including from needlestick injuries (see Ch. 20); if
you sustain a needlestick injury, report it - do not hope for
the best. In emergency circumstances do not unnecessar-
ily place yourself at risk.
3. Alcoholism and drug taking impair your judgement,
put your patients at risk and also risk your career.
4. If you develop any condition that places your
patients at risk, either because it impairs your perfor-
mance or because you may pass on an infection, you must
immediately seek a medical opinion
5. If one of your colleagues develops a condition that
threatens the welfare of patients you must exhort him
or her to seek medical care. If your advice is rejected,
remember that your first loyalty must be to the patients.
In the past we have placed loyalty to our colleagues above
our responsibility to our patients.
ERRORS
1. There are errors of judgement. Such errors arise from
the complexity of weighing the multiple factors to be
taken into account.
228
GOOD SURGICAL PRACTICE
21
Key points
• Errors of judgement are inevitable in medicine
and surgery. The problems are too complex,
rarely black and white, often affected by
unknown and unknowable factors. Accept that
you will inevitably make judgements that
prove wrong in retrospect.
• Success is not always a sign of good
judgement; robust patients survive poor
management. Equally failure may result from
factors you could not have anticipated.
2. We all make them. Often we recognize errors in ret-
rospect because we have more information, especially the
outcome of our earlier decisions. As we gain experience
we hope to reduce the number of errors we make in the
future. We hope to learn from our own errors and from
the errors of others.
3. A different type of error is sometimes called a
'systems 7 error, perhaps because it could be prevented by
changes in the way in which the system works. Examples
are the administration of a harmful substance, or adminis-
tration by an incorrect route. The first of these could be pre-
vented by placing the harmful substance out of easy access;
the second could be prevented by making the connection
of a type that can be made only to the correct acceptor.
Comparisons are often made between medical errors and
those that occur in aeroplanes. In the former there is a ten-
dency to apportion blame and label it, 'human error'. This
makes no contribution to preventing repeated errors but it
dissuades those who make errors from declaring them. If
an airline pilot makes an error and admits it, attempts are
made to study it and consider whether some change in the
system could prevent it from occurring again. Be prepared
to report when things go wrong but should have gone right
- these are sometimes pompously called 'adverse incident
reports 3 ' (AIR)s. In bringing them to attention you may be
saving future patients and colleagues from disaster.
4. As a trainee, report any error to your chief without
delay. Do not attempt to deal with it beyond your com-
petence, hide it or blame it on others. Honestly admitted
errors are excusable; failure to admit to them loses the
trust of your chief.
Key point
Gain and retain the trust of your chief. The
greatest compliment your chief can pay you is
to say, 'If that person is on call for me at night,
I sleep well/
COMPLAINTS AND CLAIMS
1. Make every effort to avoid patient dissatisfaction by
adhering to good surgical practice and maintaining
good, open relations with your patients.
2. Keep complete, up-to-date, comprehensive,
comprehensible records of what you have done, what
is happening, what your plans are, what you have
discussed with your patients.
3. If, in spite of your best efforts, there are
complications, or patients are disappointed with the
results, openly declare the situation and state what
you intend to do.
4. Do not hesitate to express your compassion if
something has gone wrong. Do not hesitate to
declare your responsibility if you have made an
error.
5. Make a written record of what passes between you
and the patients.
6. Continue your normal careful comprehensive
treatment.
7. Cooperate with any investigation.
m Further reading
1997 The surgeon's duty of care: guidance for surgeons on
ethical and legal issues. Senate of Surgery of Great Britain
and Ireland, London
2001 Good medical practice. General Medical Council, London
2002 Good surgical practice. Royal College of Surgeons of
England, London
Useful link
www.rcseng.ac.uk Code of practice for the surgical
management of Jehovah's Witnesses. Royal College of
Surgeons of England 1996 (available on line only)
229
Surgical access: incisions, and
the management of wounds
D. J. Leaper, L Low
Objectives
Be aware of the technical factors
contributing to wound infection.
Understand the principles underlying
choice and techniques of wound access.
Accept the need for aftercare of surgical
wounds.
There are records which describe successful wound
management from as long ago as the time of the
Assyrians and the ancient Egyptian Empire. Techniques
using sutures and threads, linen adhesive strips, and
even soldier ant heads as skin clips, have all been
described historically. The management of wounds, their
classification, surgical dressings and subsequent healing
is an ever-evolving field based upon a better under-
standing of the pathophysiological principles behind
them. From the time of Hippocrates and Galen, who rec-
ognized that infection impaired wound healing, to the
development of antiseptic and aseptic technique through
the work of Semmelweis, Pasteur and Lister, research
continues into the factors that affect the quality of
healing, cosmetic outcomes and the functional recovery
of the damaged tissue.
The development of operative surgery and anaesthesia
seems to know no bounds, yet the fundamental process
of wound healing must not be forgotten. The aphorism of
'cut well, sew well, get well' depends on a knowledge of
wound healing mechanisms and the adverse effects that
may influence them.
SURGICAL ACCESS AND INCISIONS
1. Before you even consider placing a knife to skin,
there are general steps to consider before each and every
case. These include correct positioning of the patient, hair
removal, sterile skin preparation and wash, and sterile
draping.
2. Should you give antibiotic prophylaxis, and deep
venous thrombosis prophylaxis (see Chs 8, 15, 19)?
3. Carefully position the patient for most advantageous
surgical access and patient safety. Take care to avoid pres-
sure, particularly on the skin over bony prominences, and
on superficial arteries and nerves. Depending on the
operation, changing body position will enhance exposure
of the area involved. Examples are the modified Lloyd-
Davis position for approach to the perineum, a lateral
position for a retroperitoneal approach to the kidney, the
prone jack-knife position for access to the rectum and
anus, the Trendelenburg position for varicose vein
surgery. Operator preference may also influence patient
position.
4. Hair removal was conventionally performed the day
before surgery. However, it has been shown that in clean
operations, shaving body hair more than 12 h before the
operation doubles the rate of wound infection. If it is
necessary, undertake shaving shortly before surgery;
supervise and check it. Clipping of hair reduces infection
rates to a tenth of those following shaving, and avoids the
risk of minor skin abrasions and cuts due to inexpert or
unsupervised shaving. Remove hair for aesthetic reasons
and to allow painless removal of dressings. Leaving it in
situ does not increase wound infection rates.
5. The most popular sterile skin preparation in the
United Kingdom is 10% povid one-iodine (1% available
iodine) in 70% alcohol. This helps by staining the skin to
demonstrate any areas that have been missed. If the
patient is allergic to iodine, use 0.5% chlorhexidine in
alcohol.
6. Now delineate the operative field with sterile
drapes. Conventionally these are resterilized double-
thickness linen sheets that are held in place with towel
clips. Take care, as they are designed for multiple use. A
drawback is that they allow permeation by body fluids
and, once soaked, can desterilize the operative field. Use
waterproof disposable fabrics which do not allow this
permeation, especially in cases of contamination, or when
there is a risk of hepatitis or human immunodeficiency
230
SURGICAL ACCESS: INCISIONS, AND THE MANAGEMENT OF WOUNDS
22
viral contamination. They are expensive. Incise drapes
of adhesive polyurethane film were introduced over
30 years ago. They are most commonly used in prosthetic
orthopaedic and vascular surgery, when there is a risk
of opportunistic infections by skin organisms such as
Staphylococcus epidermidis. Newer versions of antibiotic-
impregnated drapes significantly reduce bacterial skin
counts, but there is no definite indication that they reduce
infection rates. In general surgery they are useful in iso-
lating stomas or other infected areas, such as a separate
infected wound that is close to the planned incision.
Wound guards may also be used to reduce wound con-
tamination during open viscus surgery but they do not
reduce the risk of wound infection.
Principles of access incisions
1. In conventional open surgery the purpose of the
incision is to allow adequate exposure of the affected area
or organ. Careful organization and planning is essential.
If the operation is unfamiliar to you, revise the anatomy
or obtain help from a more senior colleague. In order to
perform any procedure competently you must have good
access, with a long enough incision to avoid excessive
retraction. Plan the incision using surface landmarks as a
guide, then perform the incision as a single movement.
This leaves a better cosmetic result than one that has been
extended. The exposed area then allows viewing, mani-
pulation of tissues and control of other structures. In some
cases, linear incisions may not provide this and angled
incisions may offer better exposure, the side within the
angle being widely retractable; for example, the roof-top
abdominal incision used for pancreatic operations.
2. When operating on limbs, do not make the incision
cross a joint perpendicular to the flexure line, as subse-
quent scarring and contracture may limit the function
of the joint on recovery. Wrinkles and contour lines
(Langer's lines) are useful to disguise resultant scars.
With a good knowledge of the anatomy, and gentle tissue
handling, damage to important structures will be mini-
mized. An assistant can also warn of potential trouble.
Nerves, tendons and vessels often lie in the most direct
path to the area affected and damage to them can impair
future function and healing; for example, vascular supply
to a skin flap and subsequent necrosis.
3. Vascular supply and wound healing. Linear incisions
rarely fail to heal because of injury to the vascular supply,
but angled incisions may do so. When an incision is made
parallel to a previous scar, for example a paramedian inci-
sion next to a midline incision, the intervening tissue is
rendered ischaemic and healing will be prejudiced. Avoid
this by reopening the old scar or excising it if there will
not be any undue tension on subsequent closure. There is
danger to underlying structures if you use an old scar
with, for example, bowel adherent to the base of an old
abdominal wound.
4. Tissue planes. Acquire an intimate knowledge of
tissue planes to obtain correct exposure. Normal anatomy
is often distorted in the presence of disease. If you dissect
in the wrong plane, you may cause inadvertent damage
and also fail to encompass diseased tissue completely, as
in cancer clearance.
5. Cosmetic aspects. The resulting scar is the only part of
the operation seen by the patient. This is particularly
important in facial surgery but an ugly scar in any area
of the body can make the patient feel self-conscious. A
young woman may feel permanently embarrassed by an
ill-planned and distorted breast scar.
6. Infection. Do not allow an initially clean operation to
become contaminated as a result of operation. In poten-
tially clean-contaminated procedures, for example elec-
tive large bowel resection, minimize and isolate any
faeculent contamination by placing clean packs around
the bowel and wound before entering the bowel. Discard
swabs or instruments once they have been soiled, change
to sterile gloves, and make use of peritoneal lavage to
wash out dirty and infected material. Antibiotic prophyl-
axis has been unequivocally shown to reduce wound
infections. In clean procedures their use is controversial.
Frequently, an operation is carried out for established
infection, or you encounter infection unexpectedly. Be
willing to limit the procedure to drainage of pus and exci-
sion of necrotic tissue. Once the wound is clean and granu-
lating you may then explore the wound and close it at a
later date. This is delayed primary or secondary closure.
Key points
• Acquire an intimate knowledge of the anatomy
to reach your objective safely, and in the right
plane.
• Remember that disease processes distort the
anatomy and may weaken the tissues.
Closure
1. The ability of a wound to heal is based upon several
factors: both local and systemic. Locally, ensure that there
is an adequate blood supply to the tissues, avoid tension,
dead space and haematoma formation. Deal adequately
with infection. Systemic factors include comorbidity such
as diabetes, jaundice or renal failure, low serum albumin
below 30 g 1 _1 , and trace element deficiencies. Ask about
medications such as corticosteroids, immunosuppressives
and cytotoxics, and enquire about previous irradiation
(see Ch. 6).
231
22
OPERATION
2. Take care to achieve the best appearance of the scar,
as the patient's perception of success is often based on the
resulting appearance, not on the speed of healing or its
ultimate tensile strength. Appose the tissues on either
side of the incision and prevent them from separating.
Inflammatory cells and fibroblasts can then bridge the
defect. Healing cannot take place if differing tissues are
opposed or other structures interposed.
3. Avoid tension when closing, particularly when
tissues are excised and the margins of excision are
brought together. This may demand a simple relieving
incision, or a more complicated flap. There are circum-
stances when tension is inevitable and you must accept
and allow for it.
4. As a general rule, repair each layer of tissue separ-
ately to restore the tissue planes. You thus avoid leaving
a potential dead space where fluid, blood or infection
may accumulate. If this is unavoidable, consider insert-
ing a drain tube, preferably a closed system, under
vacuum; remove it as soon as possible to avoid an
ascending infection.
5. Control bleeding. If you do not, you risk haematoma
formation, thereby separating the tissues. This prevents
healing and becomes a nidus for infection.
6. The opposing edges are most frequently united
using sutures. Choose materials that provide maximum
strength and minimum tissue reaction. Historically,
natural substances were popular, such as silk and catgut,
which is now avoided for fear of transmitting prion dis-
eases. 'Prions', coined from 'proteins', are transmissible
'rogue' proteins postulated to cause diseases. They are
now replaced by synthetics that behave reliably, whether
they are intended to be absorbed or to remain relatively
unchanged.
Key point
The need to restore tissue planes is vital when
structures move against each other; tendons
adhere and become fixed if they are not
resheathed in flexible areolar tissue.
Laparotomy incisions
1. Opening the abdomen has some special aspects. The
choice of incision depends on the purpose of the
intended operation. When it is performed to carry out
a specific procedure, place the incision to provide
maximum exposure (Fig. 22.1). If you are exploring the
abdomen, use a midline vertical incision or paramedian
approach in adults. The paramedian (Greek para - beside
+ Latin medius = middle) incision passes through the
Fig. 22.1 Favoured laparotomy incisions:
A, paramedian; B, midline; C, Kocher; D, transverse;
E, Lanz; F, Pfannenstiel.
rectus sheath but you can draw aside the medial part of
the intact rectus muscle. It acts as a shutter on closure
(Fig. 22.2). In infants, transverse incisions may be more
appropriate.
2. Intra-abdominal pressure is unavoidable in closure
of the abdomen, therefore tension is inevitable. If the
abdomen is distended, this increases tension. Avoid the
factors that increase the risks of wound dehiscence and
incisional hernias.
3. Delay closing the abdomen if this will so increase
tension that it creates abdominal compartment syndrome,
risking respiratory complications, sepsis and organ
failure.
4. Upper abdominal incisions are more likely to
dehisce (Latin de - intensive + hiare = to gape) than lower
incisions; it is rare for Pfannenstiel, transverse or appendix
wounds to dehisce. The lateral paramedian incision is vir-
tually free of risk of dehiscence, and has a very small risk
of hernia formation. Hernias through laparoscopic ports
are now well recognized and various techniques have
been described to close them.
5. The value of layered closure or mass closure has also
been debated. The wound dehiscence rate following
layered closure with catgut sutures fell from approxi-
mately 10% to less than 1% when using a mass closure
232
SURGICAL ACCESS: INCISIONS, AND THE MANAGEMENT OF WOUNDS
Standard
paramedian
Midline
Lateral
paramedian
Fig. 22.2 Lateral and standard paramedian incisions: a = 2 cm; b = two-thirds from midline to lateral rectus sheath.
with a non-absorbable suture. As a result of the work of
Jenkins (1976), a surgeon at Guildford in Surrey, wound
dehiscence occurred in only 1 in 1505 cases using a non-
absorbable, continuous mass suture. He hypothesized
that the suture used should be at least four times the
length of the incision, placed 1 cm from the wound edge
and not more than 1 cm apart. The suture tension should
be just sufficient to oppose the edges. Do not draw sutures
too tightly, rendering the edges ischaemic or causing the
sutures to cut through, allowing buttonhole hernias to
form through the lateral suture line.
6. Use of an absorbable thread may avoid 'cutting
through' of a suture. Polydioxanone (PDS), polyglactin
(Vicryl), and polyglycolic acid (Dexon) are predictably
absorbed and their tensile strength is long lasting.
7. Prevention of intra-abdominal adhesions has gained
interest, in the hope of avoiding the morbidity associated
with subsequent small bowel obstruction. Minimize tissue
trauma and irritation, handle the tissues gently, use non-
reactive suture materials, avoid drying and cooling the
tissues by using frequent, warmed sterile saline lavage.
Steroids, non-steroidal anti-inflammatory drugs and
dextran have all been used but their efficacy is unknown.
Newer techniques involve using a sodium hyaluronate-
based bioresorbable membrane or 0.5% ferric hyaluronate
gel (Intergel) solution, which have been shown to be effi-
cacious at a second look laparoscopy 6-12 weeks later.
Whether they have a long-term prophylactic effect has not
been proven.
Key point
• Avoid complications by correctly siting the
incision, choosing the correct materials to close,
and employing impeccable technique
throughout.
Chest incisions
There are three principal routes into the chest. The lateral
thoracotomy follows the line of the upper edge of a rib,
avoiding the neurovascular bundle under the rib. It
allows exploration of the hemithorax for trauma or pul-
monary surgery. In some cases a combined thoracoab-
dominal incision is used. This usually continues the line
of an incision along one of the lower ribs and is carried
through the costal margin into the abdomen. Endoscopic
procedures can be undertaken for cervical sympathec-
tomy It gives outstanding exposure of the lower third of
the oesophagus and fundus. Access to the pericardium,
heart and great vessels is achieved through a median
sternotomy.
PRECAUTIONS AGAINST LOSS OF
INSTRUMENTS OR SWABS
1 . Correctly organize instrument trays, limiting the
number of individually packed instruments as far as
possible.
2. Arrange swabs and packs in 'fives' bound together
with red cotton, or, if small, carefully packaged, for
example on a safety pin.
3. Check the number of instruments on trays against
printed lists incorporated in each pack.
4. Record all sutures, packs, swabs, needles and extras
clearly and legibly on a board in the theatre.
5. Use special swab racks, including the modern
disposable wallets, which facilitate counting at the
end of the operation.
6. Mark radio-opaque, non-implantable, non-metallic
equipment such as drains and the laparomat
7. Sign the theatre record book and have it
countersigned by the scrubbed and assistant
nurses.
233
22
OPERATION
8. Ensure the count is complete and correct before you
commence closure.
9. Record and sign that the count was correct at the end
of the operation note in the patient's record.
tk~
Key points
Establish a simple routine of accountability,
and a permanent and accurate record.
Precautions are like a chain - every link must
be intact or it fails.
SKIN CLOSURE
^;^&'&3^^^-59&^
1. Close skin perfectly, avoiding tension and inversion
of the edges. Several techniques are available: continuous
or interrupted, simple or mattress and subcuticular. All
are acceptable but the last gives the best results.
2. Skin clips give a good cosmetic result, are easy to
apply and remove, and are associated with a low infection
rate.
3. Tape closure using Steri-strips also gives good
results, and does not disrupt the blood supply to the
tissues, as sutures might They do, however, require a dry
surface for adhesion. They act as an adjunct to sutures
and spread wound tension to provide the best cosmetic
effect.
4. Cyanoacrylate skin adhesives are expensive and
demand near perfect haemostasis. They may be most
appropriate in children for closing lacerations.
5. Remove sutures at, as a working rule, 3-5 days in
head and neck, 7 days inguinal and upper limb, 10 days
abdominal and lower limb, and up to 14 days for dorsal
incisions. Place knots well to the side of the incision to
facilitate removal.
Hypertrophic skin scars
These present as a proliferation of heaped-up and red scar
tissue, but this stays within the boundaries of the wound
and do not extend beyond it, as do keloids. They tend to
occur in scars around joints and in areas of skin tension.
With the passage of time, at least 6 months, they become
avascular, and may regress to form a white, stretched,
widened scar. It is alleged that covering these scars with
a silicone gel produces a clinical improvement but the
exact mechanism is still unknown.
Contractures
Do not confuse these with the normal process of wound
contraction. Contractures follow delayed wound healing
and occur after infection and inadequate treatment of
deep burns in particular. Established contractures can be
released by excising them and covering the raw area with
split-thickness grafts or with transposition flaps.
Keloids
Formed by abnormal collagen metabolism, keloids (Greek
chele = claw) result in a proliferation of scar tissue beyond
the boundaries of the original wound. They occur in
dorsal areas of the body and over the face and delto-
pectoral region. Keloids occur most frequently in dark-
skinned people and may be encouraged to form as a
cultural body decoration.
Simple excision is almost always followed by a more
exuberant recurrence. X-rays have been used but topical
steroid creams or steroid injections are more effective.
Pressure on an excised keloid scar may also prevent recur-
rence. Experimental work is in progress, using calcium
antagonists and manipulating the effects of transforming
growth factor p.
SURGICAL DRESSINGS
Langer's lines
The lines described by the Viennese Carl von Langer in
1861 mainly correspond with the skin tension lines and
natural skin creases. An incision across them risks an
unacceptable hypertrophic scar. Whenever possible,
incise along the tension lines. If you have to cross them for
surgical access, as in operations on small joints, cross the
skin creases obliquely or employ Z-plasties, or plan an
S-shaped incision.
The ideal surgical dressing does not exist, but should:
1 . Be absorbent and able to remove excess exudate
2. Maintain a moist environment, aid tissues to remove
necrotic material, and promote healing
3. Prevent trauma to underlying healing granulation
tissue and exclude foreign particles from the wound
4. Be leak-proof, preventing "strike through' (passage of
organisms through soaked dressings) causing
secondary infection
5. Maintain temperature and gaseous exchange
234
SURGICAL ACCESS: INCISIONS, AND THE MANAGEMENT OF WOUNDS
22
6. Allow easy, pain-free, simple dressing changes, with
less frequent application and removal
7. Be odourless, cosmetically acceptable and comfortable
8. Be inexpensive.
The last 30 years have seen an increasing depth of under-
standing of wound healing processes. Many dressings are
now manufactured to provide the requirements of the
ideal wound environment. There is no clear-cut evidence,
however, as to whether wounds should be left open, with
a dry surface of fibrinous coagulum which seals the
wound, or whether they should be covered and hidden
from view. Exuding wounds are at risk of secondary
infection and may not be protected by a dressing.
Pathogenic organisms can track through a soiled wet
dressing from its surface. Only some of the requirements
listed above are based on sound experimental evidence.
The armamentarium of modern surgical dressings is
intended for managing chronic open wounds such as
venous leg ulcers.
Polyurethane incise drapes have become popular as a
primary wound dressing for sutured wound and skin
donor sites. They retain moisture, which enhances epithe-
lial closure, and allow easy inspection and aspiration of
excessive exudate. They are claimed to relieve pain at
donor sites. They are gas and water- vapour permeable
but if the wound becomes macerated (Latin macerate = to
soak) there is a risk of secondary infection. However, the
dressings are impermeable to organisms. More traditional
wound dressings include perforated absorbent plastic
film, such as Melolin, or non-adherent sheet dressings,
which require a secondary pad dressing if there is exces-
sive exudate.
A wide choice exists for managing open wounds such
as a healing pilonidal sinus cavity or a superficially rup-
tured, infected abdominal wound. Moulded polymeric
silicone gel foam dressing is ideal, allowing pain-free
wound care. The patient may be able to perform this.
Bead and powder dressings, such as the exudate-
absorbent Iodosorb and the sterile hydrogel mtrasite, may
be useful. Some incorporate antibiotics or antiseptics.
They absorb exudate and maintain a moist environment.
Reserve sheet polymeric hydrocolloid or hydrogel dress-
ings for more superficial open wounds. They may be
occlusive, such as Comfeel ulcer dressing and Granuflex,
or semiocclusive, such as Geliperm. Some are biological
alginates, such as Kaltostat and Sorbsan, and may be
interactive, promoting granulations. The list of dressings
increases, and satisfactory trials are required to show their
merit and comparative worth. Biologically active dress-
ings and living skin equivalents are examples of these.
Key point
Choose wound dressings of proven
cost-effectiveness, not for novelty value.
PRINCIPLES OF WOUND
1. An operation is a responsibility undertaken with
informed consent (see Ch. 14), performed in optimal cir-
cumstances. Surgery is based on ritual and it is difficult
to measure the quality of operative surgery, although we
achieve much through audit and morbidity and mortal-
ity meetings.
2. Lord Moynihan (1865-1936) taught that an operation
should start with a clean sweep of the knife. William
Halsted (1852-1922) preached gentleness, haemostasis,
asepsis and accurate apposition of tissues. While aseptic
procedures and swab and instrument counts are easy to
teach, gentle handling of tissues is more difficult to learn.
Some trainee surgeons acquire it naturally, others take
time to be able to oppose cut tissues perfectly without
undue suture tension. It is logical to secure haemostasis
in surgical wounds. These principles were directed to the
whole of surgery but apply particularly to the creation
and management of surgical wounds.
Summary
• Do you understand the complex influences
acting on incidental and surgical wounds?
• How will you select appropriate incisions,
particularly in the abdomen, the chest and
near joints?
• What principles underlie surgical closure
of wounds?
• Can you justify your selection of wound
dressings based on evidence or
experience?
References
Jenkins TPN 1976 The burst abdominal wound: a mechanical
approach. British Journal of Surgery 63: 873-876
235
22
OPERATION
Further reading
Anonymous 1986 Dressings for ulcers. Drug and Therapeutics
Bulletin 24: 9-12
Cox PJ, Ausobsky JR, Ellis H, Pollack AV 1986 Towards no
incisional hernias: lateral paramedian versus midline
incisions. Journal of the Royal Society of Medicine 79:
711-712
Harland RNL, Irving MH 1988 Surgical drains. Surgery
1: 1360-1362
Leaper DJ 1985 Laparotomy closure. British Journal of Hospital
Medicine 33: 317-322
Leaper DJ 1992 Local effects of trauma and wound healing. In:
Burnand KG, Young AE (eds) Ian Aird's companion to
surgical studies. Churchill Livingstone, Edinburgh, ch. 2,
pp 27-35
Leaper DJ 1992 Surgical factors influencing infection. In: Taylor
EW (ed.) Infection in surgical practice. Oxford University
Press, Oxford, ch. 3, pp 18-27
Leaper DJ, Foster ME 1990 Wound healing and abdominal
wound closure. In: Taylor I (ed.) Progress in surgery.
Churchill Livingstone, Edinburgh, vol. 3, ch. 2, pp 19-31
Lucarotti ME, Billings PJ, Leaper DJ 1991 Laparotomy, wound
closure and repair of incisional hernia. Surgery 10: 1-6
Wadstrom J, Gerdin B 1990 Closure of the abdominal wall: how
and why. Acta Chirurgica Scandinavica 156: 75-82
236
Minimal access surgery
A. Darzi
Objectives
• Understand the nomenclature and
boundaries of minimal access surgery.
• Recognize that minimal access surgery
aims to accomplish surgical therapeutic
goals with minimal physical and
psychological trauma.
• Recognize the limitations of minimal
access surgery in its current state,
considering future improvement in
training and technology.
Diseases that harm call for treatments that harm less.
William Osier
the essential attribute is the reduction of surgical trauma.
Other terms include endoscopic keyhole and laparo-
scopic surgery.
Technology has effectively miniaturized our eyes and
extended our hands to perform microscopic and macro-
scopic operations in places that formerly could be reached
only through large incisions. It has also provided new
ways to look at tissues, using light, sound waves and
magnetic fields which can detect disease and guide
therapy (Darzi et al 1993). These same technologies, more
highly focused and used at much higher power, can also
be used to give highly controlled resection and tissue
destruction. You must understand the principles of these
devices so that you can help to shape the future develop-
ment of minimal access surgery and not become the
servants of the machines you use.
INTRODUCTION
BOUNDARIES OF MINIMAL ACCESS
SURGERY
Minimal access surgery aims to accomplish surgical thera-
peutic goals with minimal physical trauma. The properly
controlled performance of minimal access surgery with
well-considered pre- and postoperative management
offers benefits, including cost benefits, without sacrificing
the quality of care of the patient. Minimal access tech-
niques are less invasive, less disabling and less dis-
figuring. With increasing experience, they offer cost
effectiveness to both health services and employers by
shortening operating times, shortening hospital stays and
allowing faster recuperation. State-of-the-art video
recording can help communication, bring the patient and
family closer to the process, improve clinical decision
making and enhance rapport.
The urologists Wickham and Fitzpatrick (1990), who
were instrumental in highlighting the need for techniques
which reduced therapeutic and surgical trauma, advo-
cated the term "minimally invasive therapy 7 . Cuschieri
(1992) argues that this inaccurately implies increased
safety but there is no correlation between invasiveness
and risk. He suggests minimal access surgery (MAS), as
Techniques
Minimal access surgery has crossed all traditional bound-
aries of specialities and disciplines. Shared, borrowed and
overlapping technologies and information are encourag-
ing a multidisciplinary approach that serves the whole
patient rather than a specific organ system. Broadly
speaking, minimal access techniques can be categorized
as follows.
1. Laparoscopy. A rigid endoscope is introduced
through a port in the abdominal wall into the peritoneal
cavity, which has been inflated with carbon dioxide
(pneumoperitoneum). Further ports are then placed in
the abdominal wall, through which operating instru-
ments can be introduced. Laparoscopic cholecystectomy
has revolutionized the surgical management of chole-
lithiasis and is now the mainstay in its management. As a
result of improved instruments and increasing experi-
ence, Nissen fundoplication, hiatal and inguinal hernia
repair, appendicectomy, and colorectal surgery are now
performed laparoscopically.
237
23
OPERATION
2. Thoracoscopy. A rigid endoscope is introduced through
an incision in the chest to gain access to the thoracic con-
tents. The lung is deflated, producing a natural cavity
without the need for gas insufflation. A common thoraco-
scope procedure is sympathectomy for hyperhydrosis.
3. Endoluminal endoscopy. Flexible or rigid endoscopes
can be introduced into hollow organs or systems for
diagnosis and therapy. Examples are the urinary tract
(cystoscopy), upper (oesophagogastroduodenoscopy) or
lower gastrointestinal tract (colonoscopy), respiratory
tract (bronchoscopy) and vascular systems.
4. Perivisceral endoscopy. Body planes can be accessed
even in the absence of a natural cavity. Examples are
mediastinoscopy, retroperitoneoscopy, and retroperi-
toneal approaches to the kidney aorta and lumbar sym-
pathetic chain. A recent example is subfascial ligation of
incompetent perforators in varicose vein surgery.
5. Arthroscopy and intra-articular joint surgery. Ortho-
paedic surgeons have long used arthroscopic access to the
knee and have now extended the techniques to other
joints, including the shoulder, wrist, elbow, hip and ankle.
Apart from diagnosis, therapeutic procedures include
meniscectomy.
6. Neurosurgeons employ minimal access procedures
within the cranial cavity and the spinal canal.
7. Combined approaches. A diseased organ may be
visualized and treated using a combination of endolu-
minal and extraluminal endoscopes and other imaging
devices.
damage, which may be as painful as the wound itself. By
contrast, during laparoscopy the body wall is retracted by
the low pressure pneumoperitoneum, giving a diffuse
force applied gently and evenly over the whole body
wall, causing minimal trauma.
3. Exposure of any body cavity to the atmosphere is
harmful because of loss of heat and loss of body fluid by
evaporation. There is evidence from the surgical literature
that the incidence of postsurgical adhesions is reduced in
laparoscopic compared with open procedures because
there is less damage to the delicate serosal coverings.
Handling of intestinal loops reduces peristaltic activity
and provokes adynamic ileus; this is reduced following
laparoscopic surgery.
Key points
Compared with laparoscopy, open laparotomy
produces more trauma, exposure, heat loss and
fluid evaporation.
Postoperative pain, immobility, the risk of
pulmonary and deep vein complications and of
adynamic ileus are more frequent following
open procedures.
There is probably a lower incidence of
postoperative adhesions following
laparoscopy.
Key point
Endoscopic techniques for diagnosis and
therapy can be adapted wherever a space
exists or can be created.
COMPARISON OF SURGICAL TRAUMA
FROM OPEN AND LAPAROSCOPIC
SURGERY
1. Most of the trauma of an open procedure stems from
the need for a wound large enough to give exposure for
safe dissection at the target site. The wound is often the
cause of morbidity, including infection, dehiscence,
bleeding, herniation and nerve entrapment. Wound pain
prolongs recovery time and, by reducing mobility, con-
tributes to increased incidence of pulmonary collapse /
chest infection and deep venous thrombosis.
2. Mechanical and human retractors exert additional
trauma. Body wall retractors tend to inflict localized
LIMITATIONS OF MINIMAL ACCESS
SURGERY
1. When performing minimal access surgery you are
remote from the operative field, using a two-dimensional
imaging system to represent the operative site. You must
learn to navigate the anatomical landscape without the
usual clues by which you judge depth.
2. The instruments are longer and sometimes more
complex than those used in open operations.
3. These two factors combine to create significant prob-
lems of hand-eye coordination, but with experience these
difficulties can be overcome.
4. Three-dimensional imaging is available,, using two
cameras side by side, delivering a stereoscopic image. It
can be used to perform robotically assisted minimally
invasive surgery. This confers benefits in the ability to
perform complex laparoscopic tasks, such as intracorpo-
real suturing. In the future, continuing cost reduction will
make elaborate image-processing techniques available for
a wide range of transformed presentations. Ultimately it
will be possible to call up any view of the operative region
238
MINIMAL ACCESS SURGERY
that is accessible to a camera presented stereoscopically in
any size or orientation, superimposed on past images
taken in other modalities. We shall need to decide which
of these many imaginative possibilities will contribute
most effectively.
5. Intraoperative bleeding may be very difficult to
control endoscopically because blood obscures the field of
vision and there is a significant reduction in the image
quality due to light absorption.
6. Some of the new procedures are more technically
demanding and are slower to perform. Indeed, on occa-
sions a minimally invasive operation is so technically
demanding that both you and patient are better served by
conversion to an open procedure. Do not feel a sense of
embarrassment or humiliation, which is quite unjustified.
It is vital for you and your patients to appreciate that the
decision to convert to open operation is not a complica-
tion but rather implies sound surgical judgement.
7. Loss of tactile feedback is a disadvantage. Laparo-
scopic ultrasonography might provide a substitute for the
need to 'feel' in intraoperative decision making. Although
ultrasonography has progressed significantly, laparo-
scopic ultrasound is still in its infancy. The rapid progress
in advanced laparoscopic techniques, including biliary
tract exploration and surgery for malignancy, provides a
strong impetus for the development of laparoscopic
ultrasound, which already offers advantages that far out-
weigh its disadvantages:
a. It offers a safe, easily performed and economic sub-
stitute for a sense of touch, allowing visualization
through tubular fluid-filled and solid organs as well as
vascular structures.
b. It differentiates between solid and cystic masses.
c. The wall layers of hollow viscera can be evaluated.
d. Better staging of tumours is possible because the
dimensions, infiltration and dissemination can be
detected.
e. Guided biopsies can be obtained.
f. It does not involve the use of ionizing radiations or
contrast media.
g. It has no contraindications, can be used during
pregnancy and can be employed at any time during the
operation.
8. In more advanced techniques, the large piece of
resected tissue, such as the lung or colon, must be
extracted from the body cavity (Monson et al 1992).
Occasionally it can be removed through a nearby natural
orifice, such as the rectum or mouth. At other times a
novel route can be used, such as extraction of a benign
colonic specimen through an incision in the vault of the
vagina. Tissue mincers, morcellators and liquidizers can
be used but have the disadvantage of reducing the
amount of information available to the pathologist.
9. Minimal access techniques are applied to staging
and resection of gastrointestinal, urological, gynaecologi-
cal and thoracic malignant tumours. Reports of tumour
implantation in port sites, particularly early on, are being
studied in a prospective controlled trial (CLASICC) of
laparoscopic colorectal resections for malignancy in the
UK.
10. There is a growing need for improved dissection
techniques in laparoscopic surgery, specifically the safe
use of electrocautery and lasers. Ultrasonic dissection and
tissue removal is utilized in a growing number of spe-
cialities. Adaptation of the technology to laparoscopic
surgery grew from the search for alternative and possibly
safer methods of dissection. Current units combine the
functions of three or four separate instruments, reducing
the need for instrument exchanges. This flexibility, com-
bined with the ability to provide a clean, smoke-free field,
saves time and improves safety.
11. Dramatic cost savings are possible with laparo-
scopic cholecystectomy, particularly as some can be per-
formed as day cases, but the position is less clear for other
procedures. In contrast, there has been a rise in the chole-
cystectomy rate, resulting from a lower threshold for
referral, following the introduction of the laparoscopic
approach - increasing the overall cost of treating symp-
tomatic gallstones.
TRAINING FOR MINIMAL ACCESS
It is probably true to say that no previous surgical inno-
vation has aroused so much public questioning of how
surgeons are trained. While the pioneers of a new tech-
nique are inevitably self-trained, patients then rightly
demand that their successors are properly trained to
perform it safely and effectively. This is particularly so in
laparoscopic surgery, which employs skills not commonly
used in everyday life.
The importance of training in minimal access surgery
has been recognized with the establishment of several
centres dedicated to teaching the fundamentals of safe
minimal access surgery. These centres, including the
Minimal Access Therapy Training Unit (MATTU) at the
Royal College of Surgeons of England, are working to
develop training methods using various methods of
simulation, allowing surgeons to complete a significant
part of their skills training before operating on patients.
Virtual reality training simulators are now in use and the
technology will improve further, to generate an artificial
environment in which surgeons can practise in complete
safety.
239
23 1
i
OPERATION
Key points
The skills you require to undertake minimal
access surgery are exceptional. Take every
opportunity to acquire and practise them.
The principles of good surgery still apply: case
selection, exposure, retraction, haemostasis,
technical expertise.
Minimal access has changed practice but not
the nature of disease. A conventional
procedure that does not make sense does not
make sense performed by minimal access
techniques.
Summary
Do you understand:
• The scope and limits of minimal access
surgery?
• The potential benefits for the patients?
• The need for careful selection and for
conversion to open surgery in response to
difficulties?
• The imperative need to train yourself
before embarking into a field requiring
exceptional skills?
Improvements in instrumentation and the development
of structured training programmes are the key to the
future of minimal access surgery. There is much that is
new in minimal access surgery; time will tell how much
of what is new is better.
The cleaner and gentler the act of operation, the less
the patient suffers, the smoother and quicker his con-
valescence, the more exquisite his healed wound.
Lord Moynihan of Leeds
References
Cuschieri A 1992 A rose by any other name: minimal access or
minimal invasive surgery. Surgical Endoscopy 6: 214
Darzi A, Goldin R, Guillou PJ, Monson JRT 1993 Extracorporeal
shock wave thermotherapy: new anti tumour option. Surgical
Oncology 2: 197-204
Monson JRT, Darzi A, Carey PD, Guillou PJ 1992 Prospective
evaluation of laparoscopic assisted colectomy in an
unselected group of patients. Lancet 340: 831-833
Wickham }, Fitzpatrick JM 1990 Minimally invasive surgery
[editorial]. British Journal of Surgery 77: 721
240
24
Principles of skin cover
P. E. M. Butler, J. L Atkins
E
Objectives
• Understand the pathophysiological
changes accompanying, and resulting
from, different types of skin loss.
• Recognize the importance of pre-existing
conditions in the skin and contiguous
tissues before the skin loss.
• Differentiate between the special features
of skin in different parts of the body.
• Identify circumstances in which primary
closure is possible, better deferred, and
contraindicated.
• Recognize the available methods of
achieving closure and their indications.
INTRODUCTION
The skin is the largest organ of the body, forming just
under a sixth of the total body weight. Skin function
varies in different parts of the body and this is reflected
in its qualities. Although the basic structure of skin is
constant, thickness and elasticity, pigmentation, and the
presence or absence of specialized skin appendages, such
as exocrine glands, nails, hair and sensory apparatus,
differ.
Skin provides a number of diverse but vital functions
to the body. Most obviously, it provides a physical barrier
to the outside world, giving limited protection against
mechanical, chemical and thermal damage as well as pre-
venting invasion by microorganisms, including viruses.
Its integrity is critical for homeostasis, maintaining the
internal milieu by providing a relatively impermeable
barrier to the passage of water, proteins or electrolytes in
either direction. Similarly, a vital role in thermoregulation
is manifest by the controlled release of sweat and vari-
ability of blood flow to the body surface, leading to heat
loss or conservation as required. Melanin pigment within
the dermis protects the skin by absorbing ultraviolet rays
of long (UVA) and medium (UVB) wavelength. Sensory
information received from sensory appendages located
within the dermis is both vast and subtle, while the
synthesis of vitamin D and deposition of fat in the
subcutaneous layer are functions of metabolic import-
ance. The appearance and feel of our skin is critical;
abnormalities are readily visible to the world at large, can
be socially stigmatizing and are a source of psychological
distress as well as physical discomfort to the affected
individual.
Skin loss through disease or trauma exposes an indi-
vidual to the risk of bacterial and viral infections, uncon-
trolled loss of serous fluid, proteins and electrolytes, and
loss of mechanical protection to vulnerable underlying
tissue. When skin wounds are very extensive they can be
painful, disabling and life threatening, as is seen in burn
injuries. Smaller wounds also deserve careful attention as
they provide a defect through which serious infections
may enter and produce life threatening conditions such
as gas gangrene, toxic shock syndrome and necrotizing
fasciitis. Chronic skin wounds can undergo malignant
transformation, as seen in Bowen's disease (intradermal
precancerous skin lesion described by the Harvard der-
matologist in 1912), which may progress to squamous cell
carcinoma.
Poorly managed wounds heal slowly, and form ugly,
weak scars with a poor functional result. Your primary
aims in restoring skin cover are to provide optimal func-
tion and form in a timely fashion. Understanding how
certain injury types affect tissue viability and lead to skin
loss is paramount. Undertake a systematic and thorough
assessment of the patient in general, and the wound in
particular, before instituting an appropriate course of
treatment and rehabilitation.
SKIN CHARi\CTERISTICS
1. You are not dealing with a homogeneous body
covering but with a varied, dynamic, responsive complex
surface overlying varying supportive tissues.
2. Skin varies in different parts of the body in thick-
ness, vascularity, nerve supply, ability to tolerate trauma,
241
24 *
OPERATION
mobility, and also in special attributes; for example,
palmar skin of the hands, and especially of the fingertips
of the index finger and thumb, are irreplaceable. Although
it is tough and able to withstand and respond to hard
usage, it is richly supplied with a variety of afferent nerve
endings, enabling us to utilize our fingers as important
sensory organs.
3. The elasticity of the skin varies with age and the
individual, producing tension lines. These tend to run cir-
cumferentially around joints and the trunk, at least in
early life. They are often named Langer's lines after Carl
von Langer, the Austrian anatomist. By puncturing
cadaveric skin with round spikes, he observed, in 1832,
how the circular defects deformed as a result of skin
tension. Incisions orientated parallel to tension lines heal
with superior scars.
4. Fetal skin heals without scar formation; at birth skin
is extremely elastic but with increasing age it becomes less
so. In old age, following loss of fat and muscle bulk, the
inelastic skin hangs in folds, especially on the abdomen
and neck.
5. Viability is reduced by defective nutrition (such as
vitamin C, zinc, protein), ischaemia, denervation, vascu-
lar congestion, inflammation and infection. The skin is
friable overlying an abscess and also in an area of celluli-
tis or erysipelas (Greek erythros ~ red + pella - skin).
6. Pathological changes may develop as a result of
exposure to solar or ionizing radiation, cancer chemother-
apy and various drug treatments. A variety of drugs, such
as sulphonamides, barbiturates and non-steroidal anti-
inflammatory substances (NSAIDs), may induce toxic
epidermal necrolysis (TEN or LyelTs syndrome), in which
fluid-filled bullae develop, separating sheets of epithe-
lium from the underlying dermis.
WOUND ASSESSMENT
H
Key point
• The history is as important as the appearance
when assessing wounds.
1 . Ascertain the timing, nature and force of the injury
sustained. Accurately describe the appearance of a
wound, and recognize how this changes over time; time
elapsed since injury influences how you manage the
wound. Ascertain exactly what tissue has been lost and
what remains; are tendons, bones or neurovascular struc-
tures exposed? These may need urgent soft tissue cover
to preserve function and prevent infection, and may
require a more complex reconstruction. Wounds present-
ing early (<48 h) exhibit features of an acute inflammatory
response. Following this acute phase, observe signs of
healing in an untreated wound with some or all of the
features of the acute inflammatory response having
dispersed. Identify slough and granulation tissue in the
wound base, with an advancing epithelial edge at the
wound margin. Chronic inflammation occurs with con-
tinuing tissue damage; the wound exhibits features of
ongoing tissue necrosis, acute inflammation, granulation
tissue and fibrous scarring.
2. If you are inexperienced you may be distracted by the
presence of an obvious or dramatic wound from other
pathology. Carry out a full, careful examination of trauma-
tized patients. Give priority to potentially life-threatening
injuries; they require urgent treatment.
3. Different mechanisms of injury compromise tissue
in different ways. Recognize and understand the effects
of patterns of injury. The severity of the wound is
affected by a number of factors. Elderly patients have
thin, delicate skin, easily lost with relatively minor
trauma compared with the skin of children or young
adults. Take note of the anatomical area; pretibial skin is
thin, vulnerable to trauma and slow to heal; skin on the
back is thick and robust, while facial skin is delicate but
heals quickly because it has a rich blood supply. Chronic
systemic steroid use produces thin, atrophic skin, easily
lost following minor trauma. Diabetics may develop
peripheral neuropathy leading to chronic or recurrent
ulceration of the lower limb; combined with micro-
vascular disease and an impaired immune response, the
ulcers heal reluctantly.
SKIN LOSS
Mechanical trauma
1. Contusion (Latin tundere = to bruise) results from
blunt trauma. This is not usually a serious skin injury, but
if it produces a haematoma, the swelling may cause
pressure necrosis of the overlying skin. In elderly or anti-
coagulated patients large haematomas may develop
following a minor blow, leading to the formation of very
large haematomas. Incise and evacuate these urgently to
prevent loss of the overlying skin. Blood loss may be great
enough to require transfusion.
2. Abrasion (Latin ab = from + radere = to scrape) is a
superficial epidermal friction injury, often patchy. The
epidermis regenerates by advancement of epithelium
remaining within the skin appendages deep within the
dermis. Healing is usually complete and can be encour-
aged by gently and thoroughly cleaning the wound with
a mild antiseptic to remove dirt or debris, and applying a
moist, non-adherent occlusive dressing. Unless you
242
PRINCIPLES OF SKIN COVER
24
remove the dirt ground into the wound, permanent skin
tattooing (Tahitian ta'tau) will develop.
3. Retraction (Latin re = back + trahere = to draw) of skin
edges occurs when it is lacerated (Latin lacerare = to tear).
Skin is innately elastic, the extent varying with age, race,
familial trait, the use of systemic steroids, smoking and
nutrition. If you are inexperienced you may mistake skin-
edge retraction for skin loss, most commonly seen in chil-
dren whose greater skin elasticity may lead to dramatic
opening up of the wound. Avoid this mistake by carefully
examining the wound and recognizing the pattern and
markings of one edge that match those of the opposite
edge if the skin has merely retracted.
4. Degloving results from severe shearing of the skin, for
example, a pneumatic tyre running over a limb, detaching
the skin from the underlying tissue. This separation may
occur superficially, or beneath the layer of deep investing
fascia, causing skin loss over a large area. The skin may
tear, or remain intact initially, disguising the severity of
this injury. Rupture of the vessels connecting the deeper
tissues to the skin commonly produces ischaemic necro-
sis of the skin and other tissues superficial to the plane of
separation. Prejudiced skin perfusion may be apparent
from an absence of dermal bleeding at the skin edges, as
may the absence of blanching followed by capillary refill,
when you apply then release pressure. Subsequently the
area of injury becomes more defined as the skin becomes
mottled, then necrotic. You may be able to resurface the
underlying tissue using a split thickness skin graft,
5. Avulsion (Latin ab = from + vellere - to pull) is the
partial or complete tearing away of tissue and may
involve skin, deeper structures such as bone, tendon,
muscle and nerve, including digits, limbs or scalp. The
force required to do this is considerable and creates a zone
of injury around the point at which the tissue separates.
Tissue is usually stretched, twisted and torn, leading to
irreversible damage, in particular of neurovascular struc-
tures. It may be possible, when you have appropriate
experience, to reattach or replant avulsed tissue using
microvascular techniques. Completely avulsed tissue can
be temporarily stored in moistened sterile gauze, sealed
in a plastic bag and placed in ice, or stored in a refrigera-
tor at 4°C. Vascular tissue such as muscle cannot be safely
replanted if it has been ischaemic for more than 6 h.
Tendon, skin and bone are more tolerant of ischaemia.
Make every effort to salvage an avulsed or amputated
upper limb, thumb, multiple lost digits, or digits in chil-
dren. They are important for restoration of function, and
especially in children they offer greater potential for
recovery. Loss of individual digits is relatively less import-
ant in terms of benefit. An avulsed toe or foot is rarely
suitable for microvascular replantation because sensory
and functional recovery is poor and therefore unlikely to
be satisfactory. If the patient has other significant life
threatening injuries you may decide against attempting to
reimplant divided tissues.
Key point
• Remember that even trivial skin loss may offer
entry to strains of Staphylococcus aureus that
may cause toxic shock syndrome, especially in
vulnerable patients such as children, the elderly
and the sick.
Thermal injury
1. A scald (Latin ex - from + calidus = warm, hot) is
caused by contact with hot liquids. A variety of agents
may cause burns, such as flames, contact with hot
objects, radiant heat and corrosive (Latin rodere = to
gnaw) chemicals.
2. Through and through electrical injuries differ from
other burns in that the passage of the electrical current
through the body causes injury to deep tissue that may
not be immediately apparent. A small entrance and exit
burn of the skin may be the only visible manifestation of
the injury. The electrolyte-rich blood acts as a conduit for
the current flow and the vascular endothelium is
damaged so that the vessels subsequently undergo
thrombosis. Deep-seated tissue necrosis becomes appar-
ent as the patient becomes increasingly unwell over hours
or days. High voltage injuries are the most destructive,
and alternating current is more likely to cause myocardial
fibrillation than direct current.
Surgical diathermy heats the tissues as a result of
intense vibration of the ions caused by the low amperage
high frequency, high voltage, alternating current (see
Ch. 17). Faulty equipment and inexpert use may result in
skin burns.
3. Exposure to cold air may cause frostbite. Excessive
exposure to cold causes peripheral vascular spasm, with
ischaemia and anoxia of the extremities, affecting a local-
ized area of soft tissue. The extent of the injury is affected
by temperature, duration of contact and pre-existing
hypoperfusion of tissues. Four phases of injury have been
described. These are;
a. Pre-freeze (3-10°C): increased vascular permeability
b. Freeze-thaw (-6 to -14°C): formation of intra- and
extracellular ice crystal.
c. Vascular stasis: blood is shunted away from the
damaged area
d. Late ischaemic phase: cell death, gangrene.
Thawing, with restoration of the circulation, liberates
inflammatory mediators. Microemboli form on the
damaged endothelium and these increase the ischaemia
and tissue loss. Treatment includes rewarming by
243
OPERATION
immersion of the affected part in circulating warm water,
elevation and splinting. Ischaemic areas are allowed to
demarcate prior to amputation of the necrotic parts.
Cryosurgery (Greek kryon = frost) offers a method of
destroying skin lesions almost painlessly (see Ch. 17).
A lesser result of exposure to cold is chilblains (Old
English blain = a boil or blister).
Contact with very cold objects can result in adherence
of the skin, which is pulled off on separation.
4. Assess burns, in terms of site, percentage of the body
surface damaged and depth of damage, to determine the
prognosis and as a guide to treatment. Depth is super-
ficial (1st degree), partial skin thickness including the
dermis (2nd degree) and full thickness of all the layers of
the skin (3rd degree). Burn depth is difficult to assess.
White, insensate areas are generally full thickness. Partial
thickness burns usually blanch on pressure and refill
when the pressure is released; it remains sensate and may
be blistered. Superficial burns are often erythematous,
perfused, painful and tender to touch.
5. Generally, full thickness burns are managed by exci-
sion and skin grafting of the underlying tissue bed; partial
thickness burns may be suitable for conservative treatment,
allowing epidermal regeneration from remaining epithelial
elements within the skin appendages of the dermis.
Ulceration
'Ulcer' (Greek elkos, Latin ulcus = sore) usually has a con-
notation of chronicity. An acute loss of skin is not called
an ulcer unless it fails to heal.
1. Pressure sores develop from unrelieved pressure on
the tissues in a debilitated patient, especially if there is
neurological impairment. Other factors include nutri-
tional deficit, diabetes mellitus, immunosuppression,
incontinence and an inappropriate physical environment.
The commonest affected areas are on the lower body
within tissue overlying bony prominences. The sore
develops as the tissue becomes compressed and oedema-
tous; the pressure within the tissue exceeds the capillary
perfusion pressure, leading to ischaemia and tissue necro-
sis. The tissue adjacent to the bony prominence suffers the
most extensive injury, with the least at the level of the
skin; the visible skin wound belies the reality of a much
more extensive tissue loss.
5"
Key point
• Development of pressure sores represents a
failure to protect skin at risk from continuing
pressure or contact with damaging substances,
including body secretions and excretions.
Treatment is predominantly conservative. Institute
measures to relieve pressure, such as the use of specially
adapted wheelchairs, beds and other padding, correct any
nutritional deficiency, eliminate infection, control incon-
tinence and apply appropriate dressings. A minority
require surgical intervention, such as wound debride-
ment, excision of the bony prominence to encourage
closure, or covering the area with a soft tissue flap. Use
flaps cautiously in the presence of chronic predisposing
illness such as multiple sclerosis.
2. Other common causes of ulceration include diabetes,
autoimmune disorders, infection, ischaemia, venous
disease and neoplastic lesions. Identify the underlying
cause, if necessary by obtaining an incisional or punch
biopsy of the margin, and treat the underlying cause. Any
chronic ulcer may undergo malignant change, with the
formation of Bowen's disease prior to malignant invasion
as squamous cell carcinoma.
3. Raynaud's disease, described by the Parisian physi-
cian in 1862, is an excessive arteriolar sensitivity to cold
of the extremities. In Raynaud's phenomenon the spasm
is secondary to vascular or connective tissue disease, or
occupations in which vibrating tools need to be used. The
spasm causes necrosis and ulceration of the extremities.
Key point
Record the progress by keeping serial
photographs of wound size, extent and
healing.
BIOLOGY OF SKIN HEALING (see also
Ch.33) ^
1. Wound healing is a multistep overlapping process
involving an inflammatory response, granulation tissue
formation, new blood vessel formation, wound closure
and tissue remodelling. Tissue damage causes extra-
vasation of blood and its constituents. Platelets and
macrophages release a number of chemical mediators
including transforming growth factors (TGF), fibroblast
growth factor (FGF), vascular endothelial growth factor
(VEGF), platelet-derived growth factor (PDGF), insulin-
like growth factor (IGF) and keratinocyte growth factor
(KGF).
2. The injured cells and other cells and platelets
generate vasoactive and chemotactic (Arabic al kimiea,
Greek chemeia + tassein = to arrange; cell movement in
response to a chemical stimulus) substances that attract
inflammatory neutrophils. Monocytes are also attracted
and convert to macrophages. These phagocytes remove
244
PRINCIPLES OF SKIN COVER
24
dead tissue and foreign material, including bacteria. As
inflammatory exudate accumulates, there is a cascade of
events leading to oedema, erythema, pain, heat and
impaired function. Macrophages and factors derived
from them are essential in stimulating repair (Singer &
Clark 1999).
3. Epidermal cells from skin appendages break
desmosomal contact with each other and also with the
basement membrane; they migrate in the plane between
the viable and necrotic tissues by producing collagenase,
which degrades the intercellular substance (matrix)
reinforced by matrix metalloproteinase. Epithelial cells
behind the migrating ones proliferate after 1 or 2 days,
probably from the release of growth factors. As re-
epithelialization proceeds, the epithelial cells reattach
themselves to the basement membrane and underlying
dermis.
4. As a result of hypoxia, growth and angiogenesis
factors are released by macrophages and activated
epithelial cells. The wound is invaded by blood capil-
laries, macrophages, fibroblasts after 3-4 days, bringing
nutrients and oxygen. The crests of the capillary loops
appear like small cobblestones, hence the name of 'granu-
lation' tissue. Blood capillaries require the presence of
perivascular fibronectins (Latin nectere - to bind, tie) in
order to move into the wound. Vascular growth is a deli-
cate balance of positive regulators such as VEGF and
PDGF, and negative regulators such as angiopoietin-2,
endostatin and angiostatin. Once the wound is covered
with granulation tissue angiogenesis stops. The fibro-
blasts synthesize extracellular matrix, which is later
replaced with acellular collagen, when cells in the
wound undergo apoptosis (Greek apo - from + piptein =
to fall; programmed cell death). During the second week
following injury, fibroblasts become myofibroblasts,
acquiring actin-containing microfilaments (Greek aktinos
= ray) and cell-to-cell and cell-to-matrix linkages.
Probably under the influence of TGF and PDGF, the
fibroblasts attach to the collagen matrix through integrin
receptors and form cross-links. Myofibroblast contrac-
tion draws together the attachments at each end of the
cell. However, in animal experiments the evidence for
the role of myofibroblasts has been questioned (Berry
etal 1998).
5. The contribution of epithelial migration and wound
contraction to healing is not fully resolved. There are also
differences in the factors involved between humans and
in animal experiments. One suggestion is that wound
contraction in granulation tissue results from the com-
paction of collagen fibres influenced by cellular forces,
not directly from contraction of cells pulling on the
surrounding tissues.
6. When closure of large raw areas has failed or is
unavailable, healing and scar formation continues for
weeks, months or years. This is often termed scar con-
tracture. Powerful forces draw in skin and scar tissue is
laid down, often causing severe limitation of function. A
classical example is that of a young child who pulls over
a pan of scalding water, burning the face, neck, shoulder,
chest, axilla and upper arm. The head is permanently
drawn to the side of the burn, the neck is webbed, the
shoulder is drawn upwards and fixed; the shoulder
cannot be abducted and the deltoid muscle atrophies,
while the anterior axillary fold and skin over the chest
circumference is tight, restricting inspiration.
7. Collagen degradation proceeds in step with wound
contraction. The wound gains only 20% of its final
strength in the first 3 weeks, and the maximum strength
it achieves is only 70% of that of normal skin.
8. Healing is prejudiced in diabetes, especially in the
presence of neuropathy and ischaemia. Wounds are prone
to infection because of impaired granulocyte function and
chemotaxis.
9. Abnormal accumulation of collagen causes hyper-
trophic scarring and keloid formation. Normal mature
scars and keloids display no scar contraction and they do
not contain any myofibroblasts. Increased levels of TGF(3,
PDGF, interleukin 1 (IL-1) and IGF-I are present in both,
with TGFp appearing to predominate.
10. Growth factors have proved disappointing in
accelerating wound healing, possibly because they need
to be administered in carefully graded doses and
sequence.
11. Fetal skin wounds heal rapidly without scarring;
the epithelial cells are drawn across the wound by con-
traction of actin fibres. Scarring does not occur because
there is a reduced level of TGFpl. PRX-2, a member of
the Paired Related Homeobox gene family, is upregu-
lated in dermal fibroblasts during scarless fetal wound
healing.
DEBRIDEMENT
1. Debris, foreign material, devitalized tissue, slough,
pus or heavy contamination with pathological bacteria
form a focus for infection, irritate the wound, prevent the
formation of granulation tissue and obstruct epithelial
migration.
2. Excise all non-viable skin under anaesthesia and, if
you are in doubt regarding viability, return the patient to
the operating theatre for a second inspection and debride-
ment after 24^8 h. Debridement (French de = from +
bridle; unbridle = release from constriction) was origi-
nally used for releasing tension but has been extended to
mean the removal of dead tissue.
3. It can often be achieved non-surgically using saline
irrigation, topical agents to lift slough or with dressings
245
24
OPERATION
or sharp dissection under anaesthesia. Debride areas with
specialized and precious tissue, such as the fingertips,
palm and face, adequately but minimally. If there is
uncertainty at the time of surgery as to the viability of
tissue or adequacy of debridement, be willing to redress
the wound with an occlusive non-adherent dressing and
return the patient to the operating theatre for a second
inspection after 24-48 h.
ACHIEVING WOUND CLOSURE AND
SKIN COVER
No skin loss
1. Clean incised wounds vary, depending on where
and how the wound is made. If it is made parallel to the
lines of tension the edges remain closely apposed, if made
across the tension lines they gape. There is virtually no
damage to contiguous tissues so that, apart from the
almost singular layer of cells along the line of division, the
remainder of the tissues are viable. Such a wound, once
closed, is said to heal by primary intention, and should
heal with a fine linear scar.
2. If the incision is only partial thickness the deeper
intact parts maintain the edges in good apposition. If the
wound extends through the full thickness this support is
partially lost, depending on the strength and attachment
of the deeper tissues.
3. Abraded skin has intact deeper layers and will heal
spontaneously. Torn skin dragged as a flap may initially
appear viable; a triangular flap attached distally over
the subcutaneous face of the tibia notoriously fails to
survive.
4. In wounds with very irregular margins, it is helpful
to close the most obvious matching points first and then
to close the other points in between. Do not be afraid to
remove and reposition sutures until the edges are per-
fectly matched. Small bridges of skin separating lacera-
tions are best excised to achieve a cosmetic result.
Skin loss
1. When a skin or other superficial lesion has been
excised, the surviving edges and the base are normally
left healthy, dry and free of bacterial contamination,
foreign material or dead tissue.
2. Closure can usually be performed immediately
(primary closure); indeed the excision is usually planned
with this in mind, except in the presence of malignant
disease, when total clearance of the tumour is paramount.
Primary closure allows more rapid healing and an earlier
return to normal function.
3. In elective surgical procedures, the closure can be
planned before operation and discussed with the patient.
It may be possible to close the defect directly, reconstruct
or resurface it.
4. As far as possible, replace large defects with skin
and tissue giving the closest possible match to the
surrounding tissues with regard to colour, thickness and
texture.
5. To achieve the best results the wound edges must be
accurately opposed. If the wound is irregular, perfect
apposition can be aided by first identifying and apposing
landmarks with key sutures before inserting intervening
sutures.
6. Perfect closure is prejudiced by unevenness, inver-
sion of the edges and tension, as inevitable postoperative
oedema increases the tension.
7. Many small wounds of 1 cm in diameter or less,
including many fingertip injuries, usually heal with
a satisfactory result by secondary intention within
2-3 weeks. Treat larger wounds conservatively in ill, frail
patients, and those likely to heal within a reasonable time.
This may include pressure sores.
Key point
Assess the nature of the skin at the margins of
the defect that you intend to close.
Complicating factors
1. The skin may be atrophic or stretched, especially in
elderly people, or affected by eczema, solar or ionizing
radiation, hypertrophy or the scar of a previous oper-
ation. Neonatal and infant skin usually heals well.
2. Inflammation, neoplasm, ischaemia, oedema, infec-
tion, congestion or injury - possibly with the presence of
foreign material - of contiguous tissues such as bones,
muscles, tendons, nerves or vessels may force a change of
strategy.
3. Repair is prejudiced if the patient is very old,
undernourished, immunosuppressed is undergoing
chemotherapy, or has general infection, neoplasia or
organ failure.
4. The wound may be too large to close.
Achieving closure
1. Grafting (Greek graphein = to write; from the
Roman use of tree grafting using shoots sharpened like
a pencil), may allow transfer of completely detached
partial or full thickness skin from a donor site to a
246
PRINCIPLES OF SKIN COVER
wound that cannot be closed directly. The graft adheres
by fibrinous bonds, initially gaining nourishment by
serum imbibition - metabolites diffusing through the
thin film of intervening serum. Capillaries connect from
the recipient site and are functioning by the second day
but the connection is fragile and susceptible to shear
stress for 2-3 weeks. The best recipient sites for skin
grafts are clean, granulating and well vascularized;
unsuitable sites include bone lacking periosteum,
tendons stripped of paratenon, denuded cartilage, irra-
diated or avascular wounds and those covered in blood
clot. Gross contamination with microorganisms preju-
dice graft survival and Streptococcus pyogenes is an abso-
lute contraindication because it produces fibrinolysin,
destroying the fibrin bond between the bed and the
graft. The likelihood of graft movement can be reduced
by applying moderate pressure with a conforming, tie-
over dressing, which will also inhibit the development
of a seroma or haematoma.
2. A split thickness skin graft consists of epidermis
and a variable proportion of dermis, harvested in sheets
using a handheld knife or electronic dermatome.
Retained epidermal components, such as pilosebaceous
follicles, provide foci for epidermal regeneration. The
thinner the graft harvested, the more epidermal ele-
ments left behind, the quicker the epidermis regenerates.
If the volume of donor skin is inadequate, split skin
grafts can be expanded by the use of a meshing machine;
this creates fenestrations throughout the graft, allowing
it to expand and cover a larger area, with a net-like
appearance. Split skin grafts can be harvested, wrapped
in sterile saline-soaked gauze and stored in a refriger-
ator at 4 Q C, with up to 3 weeks viability. The common-
est donor site for these grafts is the thigh or buttock area.
The donor site often heals with altered pigmentation,
and occasionally with a hypertrophic scar. Split thick-
ness grafts, especially thin ones, tend to contract during
the healing process, limiting movement across flexor
surfaces. The application of compression garments when
the graft is healed improves the appearance, flattens the
scar and minimizes contraction, aided by daily massage
with moisturizing cream.
3. Full thickness skin grafts comprise the epidermis
and full thickness of the dermis. It is harvested using a
template to plan the size and shape, and subcutaneous fat
is removed. The donor site, such as post- or preauricular,
supraclavicular or groin, is closed directly. It generally
provides good colour match on the face and contracts
minimally. Such grafts are inevitably limited in size and
must be placed on a healthy, vascular base.
4. Flaps are detached tissue, containing a network of
arterial, venous and capillary vessels, transferred from
one site to another. They can retain their intact circulation
on the original vascular pedicle. Random pattern flaps do
not have an anatomically recognized vascular supply and
as a general rule the length of the flap should not exceed
twice the length of the attached base. Some flaps have
identified vessels supplying them - axial pattern flaps,
including the forehead, groin and deltopectoral region;
these may be raised on a narrow pedicle and discon-
nected completely, for the vessels to be joined to vessels
at the recipient site - a free flap. This is achievable as a
result of microsurgical techniques. They may include
other tissues, including deep fascia, muscle or bone.
Useful sites include the forehead, groin and deltopectoral
region.
5. Myocutaneous flaps provide a robust vascularized
wound cover over exposed bone, tendon or areas sub-
jected to high mechanical demands. Skin in many areas is
supplied by perforating vessels from the underlying
muscle and an island of skin can be transferred with the
muscle to provide simultaneous skin cover. The muscle is
isolated onto its vascular pedicle alone and rotated into
the defect. Commonly used myocutaneous flaps include
the latissimus dorsi, rectus abdominis, pectoralis major
and gastrocnemius.
6. Deep fascia included with overlying layers of skin
improves vascularity and safety; they can also be trans-
ferred as vascularized free flaps.
7. Tissue expansion allows the skin and subcutaneous
tissue to be stretched in order to nil a defect nearby An
expandable silicone (Silastic) bag is inserted beneath the
skin and subcutaneous fat. When the wound is healed,
the sac can be filled percutaneously with increasing
volumes of saline though a special subcutaneous port.
Once the overlying skin is sufficiently stretched, the
implant is removed and the stretched excess skin can be
advanced into the defect.
SKIN SUBSTITUTES
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Wound coverage is vitally important. If sufficient skin is
not available it may be possible to apply a substitute. The
main need for these substitutes is in the management of
extensive burns.
1. Autologous (derived from the same individual)
cultured epidermal cells provide permanent coverage
but they require 3 weeks in order to grow sufficient
cells.
2. Allografts (Greek alios = other; from another indi-
vidual) cultured epidermal cells from living persons or
cadavers do not appear to be rejected, possibly because
they do not express major histocompatability complex
247
24
OPERATION
ir - ..vvjjjimmK
class II antigens and are not contaminated with
Langerhans cells, which are the antigen-presenting cells
of the epidermis. They are eventually replaced by host
cells, so they offer temporary coverage.
3. Neonatal epidermal cells, for example from excised
foreskins, release growth factors. Cultured cells accelerate
healing and relieve painful chronic ulcers,
4. A composite collagen-based dermal lattice in a sili-
cone covering may be valuable in the treatment of burns.
The dermal cells are gradually degraded but after 3 weeks
the Silastic sheet cover can be removed and replaced by
cultured autologous cells. Human epidermal cells and
viable fibroblasts may be included in the composite.
Viable fibroblasts may also be included in a nylon net
cover overlaid with Silastic to reduce evaporation.
5. In order to provide substitute dermal as well as
epidermal cells, bovine collagen and allogeneic human
cells may be combined.
Summary
• Are you aware of the multiplicity of
factors to which the skin is exposed?
• Do you recognize the varied causes of skin
damage and loss?
• Do you understand the complex biology of
skin healing?
• Can you discuss the methods of skin
closure?
References
Berry DP, Harding K, Stanton MR, Tasani B, Ehrlich HP 1998.
Human wound contraction: collagen organization, fibroblasts
and myofibroblasts. Plastic and Reconstructive Surgery 102:
124-131
Singer AJ, Clark RA 1999. Mechanisms of disease: cutaneous
wound healing. New England Journal of Medicine
341: 738-746
Further reading
Brough M 2000. Plastic surgery in general surgical operations,
4th edn. Churchill Livingstone Edinburgh, pp 727-773
Kirk RM 2002 Basic surgical techniques, 5th edn. Churchill
Livingstone, Edinburgh
McGregor I A, McGregor AD 1 995 Fundamental techniques in
plastic surgery and their surgical applications. Churchill
Livingstone, Edinburgh
Nedelec B, Ghahary A, Scott PG, Tredget EE 2000, Control of
wound contraction. Basic and clinical features. Hand Clinics
16: 289-302
Richard R, DerSarkisian D, Miller SF, Johnson RM, Staley M
1999. Directional variance in skin movement. Journal of Burn
Care and Rehabilitation 20: 259-264
Saba AA, Freedman BM, Gafh'eld JW, Mackay DR, Ehrlich HP
2002. Topical platelet-derived growth factor enhances wound
closure in the absence of wound contraction: an experimental
study. Annals of Plastic Surgery 49: 62-66
Witte MB, Barbul A 2002. Role of nitric oxide in wound repair.
American Journal of Surgery 183: 406^412
Younai S, Venters G, Vu G, Nichter L, Nimni E, Tuan TL 1996.
Role of growth factors in scar contraction: an in vitro
analysis. Annals of Plastic Surgery 36: 495-501
248
Transplantation
P. McMaster, L. J. Buist
w
Objectives
Appreciate the causes of organ rejection.
Understand the principles of
transplantation and immunosuppression.
Be aware of the source of transplanted
organs, and the associated ethical and
legal considerations.
Table 25.1 Forms of tissue transfer
BASIC PRINCIPLES
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Early Christian legends attest to the attempts to replace
diseased or destroyed organs or tissues by the transfer
from another individual. The father of modern surgery,
John Hunter, carried out extensive experiments on the
transposition of tissues and concluded what he thought
were successful experiments on the transposition of teeth!
However, it was not until the dawn of the 20th century
that the practical technical realities of organ transfer were
combined with sufficient understanding of the immuno-
logical mechanisms involved to allow transplantation to
become a practical reality.
While it had long been recognized that successful blood
transfusion was in large measure dependent on matching
donor and recipient cells, it was only in the 1950s that
Mitchison (1953) demonstrated that, while cell-mediated
immunity was responsible for early destruction and
rejection, it was the humeral mechanism with cytotoxic
antibodies that was primarily involved in the host
response to foreign tissue. It became increasingly recog-
nized that all tissue and fluid transfer was governed by
basic immunomechanisms (Table 25.1).
The need in the Second World War to find improved
ways of treating badly burned pilots led Gibson &
Medawar (1943) to carry out a series of classic experi-
ments on skin transplantation. They were able to con-
clude that the transfer of skin from one part of the body
to another in the same individual (an autograft), survived
indefinitely, whereas the transfer of skin from another
• Transfer of tissue
Blood
Bone marrow
* Tra nsf er o f solid o rga n
Skin
Cornea
Kidney
Heart
Liver
Pancreas
individual (an allograft) was in due course destroyed and
that the recipient retained memory of the donor tissue
and further transfers or allografts were destroyed in an
accelerated mechanism. Thus the wider recognition of
the universal acceptance of autografts became realized,
whereas the failure of an allograft was recognized as part
of an immune response. An alternative source of organs
is, of course, the animal world, and the transfer from
another species is known as a xenograft.
FIRST CLINICAL PROGRAMMES
The recognition that an autograft would be universally
acceptable led to the first successful attempts at organ
grafting in humans. In the early 1950s, Murray et al (1955)
at the Peter Bent Brigham Hospital in Boston, were able
to demonstrate the successful transfer of a kidney graft
from an identical twin, with acceptance and successful
function, and to develop a programme of renal trans-
plantation between monozygotic twins.
Some of the recipients of kidney transplants from
identical twins remain well more than 40 years after
grafting; however, grafts between unrelated living indi-
viduals performed by this same group invariably failed,
although not as quickly as experimental studies might
have suggested.
249
25
OPERATION
RESPONSE
The other major human source of organs, other than from
living relatives, is from individuals who have died as a
result of road traffic accidents or cerebral injuries.
Cadaveric organ grafting from non-related individuals is
now the major source of organs. Within Europe, more
than 80% of all organs transplanted are from brain-dead
donors.
Thus, although technical considerations presented the
initial formidable barrier to organ transfer, it was increas-
ingly the understanding of the immune response causing
organ destruction by rejection, which led to clinical
schedules permitting practical transplantation services to
be established. The body's immune response to destroy
the invading organ we now recognize as rejection.
REJECTION
Early experimental studies involving tissue transfer sug-
gested genetic regulation of the rejection process. It was
suggested in the 1930s that rejection was a response to
specific foreign antigens (alloantigens) and that they were
similar to blood groups of other species. The development
of inbred lines of experimental animal models allowed
the demonstration of antigens present on red blood cells
and the concept of histocompatibility. This suggestion of
an immunological theory of tissue transplantation stimu-
lated Meda war's (1944) work in rabbits and later in mice,
and led to similar studies in humans, with the discovery
of the human leucocyte antigen (HLA) system.
Further experimental studies defined the concept of
rejection into three primary categories: hyperacute rejec-
tion, which can occur in a matter of hours due to pre-
formed antibodies in a sensitized recipient; acute rejection,
which takes place in a few days or weeks and is usually
caused by cellular mechanisms; and chronic rejection,
which occurs over months or years and remains largely
undefined, but involves primarily humeral antibodies. A
detailed review of experimental and modern transplan-
tation biology is quite beyond the scope of this chapter,
but increasing understanding of this area will allow more
refined changes in rejection management and increas-
ingly successful organ grafting.
AVOIDING REJECTION
The degree of disparity between donor and recipient is an
important key element in the severity of the immune
rejection response. In xenografting (transfer between
species) the presence of preformed antibodies leads to
rapid endothelial damage, causing vascular thrombosis,
gross interstitial swelling and necrosis of the graft, all
within a matter, usually, of hours.
Similarly, when transfer occurs between human beings,
the degree of compatibility between donor and recipient
is important to the success, or otherwise, of the graft.
As indicated earlier, transfer between identical twins is
associated with universal success, without the need to
modulate the immune mechanism. However, transfer
between non-identical relatives or using cadaveric
organs produces the recognition of non-self by the re-
cipient and the mounting of an immune response. It is
the avoidance or modification of this immune response
that has been the main target over the last 25 years, and
the avoidance of overwhelming rejection has been a
prime goal.
Two approaches have been taken to the problem: tissue
typing and reduction of immune response.
Tissue typing
In the attempt to match the donor and recipient more
closely, the concept of typing has become widely devel-
oped. Early work demonstrating that blood transfusion
was dependent on matching between donor and recipient
was extended into experimental and then clinical trans-
plantation studies in the 1960s and 1970s.
The human chromosome 6 contains the genetically deter-
mined major histocompatibility complex (MHC), i.e. the
HLA-A, HLA-B, HLA-C (class I) and HLA-DR (D-related;
class II) loci. A whole series of additional genetic regions
have been linked to the HLA complex, although in clinical
terms these are probably less significant.
Thus it has become increasingly possible, using sero-
logical studies, to map genetically an individual on the
basis of the HLA region of this chromosome. Since one
chromosome is inherited from each parent and each indi-
vidual has two HLA haplotypes, there is a 25% chance
that two siblings will share both haplotypes (i.e. identi-
cal) and, by standard and mendelian inheritance, a 50%
chance that they will share one haplotype. Thus in first-
degree relatives when the donor and recipient are
matched for HLA-A and -B antigens there is an excellent
likelihood of graft success, whereas because of the com-
plexity of the MHC allele, the wide divergence of anti-
gens and random cadaveric donors, even if matched for
one or two antigens, there may still be very substantial
disparity.
Thus, in order to avoid rejection, the concept of tissue
typing trying to match more accurately the donor and
the recipient has gained wide acceptance. Serological
methods allow class I HLA antigens to be defined using
typed serum obtained from nulliparous women. Using a
microcytotoxicity assay, multiple antisera against HLA-A,
-B, -C and -DR antigens are provided on Terasaki trays
250
TRANSPLANTATION
25
and then frozen until required. When needed, the trays
are thawed and the donor lymphocyte cells are added to
the wells containing complement and the antisera against
specific HLA types. If the antibody causes the cells to lyse,
acrid ine orange (a dye) enters the damaged cell and
appears orange under fluorescence microscopy. Thus, by
using microcytotoxicity tests it is possible to identify quite
rapidly the HLA class I antigens present in a donor.
Until recently class II antigen typing required a mixed
leucocyte reaction to determine individual constituents,
but more recent techniques have avoided this laborious
investigation. From the clinical standpoint the practical
importance of identification of the degree of compatibil-
ity between donor and recipient is clearly defined in
many organ-grafting systems. Cadaveric grafting can
only achieve this level when beneficially matched donor
and recipient pairs r in which all major class I and class II
antigens are identical, are grafted. This so-called 'full
house' HLA match can give 1 year cadaveric graft sur-
vival approaching 90%. However, this is only when com-
bined with chemical non-specific immunosuppression.
When grafts are transferred between cadaveric donor
and recipient with a complete mismatch an additional
20-25% of grafts will be lost over the ensuing 5 years.
Thus, in cadaveric grafting the degree of matching has an
important role in determining the severity of the immune
response and the ultimate success, or otherwise, of the
graft.
Nevertheless, no matter how good the matching is in
cadaveric situations, modulation of the immune response
continues to be necessary to ensure graft survival.
Reduction of immune response
Reduction in the immune response occurs frequently in
clinical practice in such situations as uraemia, profound
jaundice and in patients with advanced malignancy and
acquired immunodeficiency syndrome (AIDS). The con-
trolled reduction of an immune response to foreign
antigen on the graft requires careful clinical judgement.
Initial attempts using widespread radiation produced
severe depletion of not just lymphocytes but also a pan-
cytopenia, and although the recipients readily accepted
skin grafts and other organs immunologically, the major-
ity of patients quickly died from overwhelming infection.
A refinement of this technique, in which partial lym-
phocyte irradiation was used, has been successful both
experimentally and in clinical practice, depleting the
immune response so that grafts can be accepted.
Chemical immunosuppression
Since the mid-1950s the primary mode of immunomodu-
lation has been the administration of chemical agents. A
demonstration by Hitchings & Elion (1959), over 40 years
ago, that 6-mercaptopurine had immunosuppressive
potential, allowed Schwartz & Dameschek (1959) to treat
rabbits stimulated by foreign antigen. The treated
animals did not produce antibodies to the antigen stimu-
lation, and work by Calne in 1960 showed that 6-
mercaptopurine could also inhibit the immune response
in dogs. A number of other agents were studied at that
time and those found to be of clear benefit were steroids,
reducing the cellular response, and eventually azathio-
prine, which showed improved results when compared
to 6-mercaptopurine.
For more than 20 years chemical irnmunomodulation
with the combination of steroids (prednisolone) and
azathioprine was to be the main non-specific immuno-
suppressant used. They inhibited the immune response
largely by depressing circulating T cells.
The production of antilymphocytic globulin by sensiti-
zation in animals was also demonstrated to inhibit the
immune response, although variability and efficacy
limited its clinical use.
Ciclosporin. Clearly the ultimate goal of selectively
inhibiting the recipient's immune response remains a
long way off, and in clinical practice non-specific agents
continue to be used. In 1976, Borel and colleagues
working in Sandoz laboratories assessed the potent
immunosuppressive properties of ciclosporin A, a cycli-
cal peptide with 11 amino acids. The demonstration of
both the in vitro and in vivo immunosuppressive activity
was quickly followed by extended clinical studies. It was
clearly demonstrated that ciclosporin could suppress
both antibody production and cell-mediated immunity,
exhibiting a selective inhibitory effect on T cell-dependent
responses. Of critical importance was the observation that
the drug was neither profoundly lympho- nor myelotoxic
and had no influence on the viability of the mature T cells
or the antibody-producing B cells. Further agents have
recently been introduced to clinical practice, perhaps
resulting in less rejection still (FK506 or tacrolimus,
mycofenolate and monoclonal antibodies).
CURRENT CLINICAL
IMMUNOSUPPRESSIVE USE
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For nearly 30 years the mainstay of clinical immuno-
suppression was the combined use of steroids and aza-
thioprine. With increasing clinical experience it became
possible to adjust the dosage of these agents so that in
many individuals it was possible to maintain immuno-
suppression and thus prevent rejection, while minimiz-
ing the risk to the recipient of over irnmunomodulation,
a delicate balance that requires considerable clinical
skill.
251
25
.
OPERATION
Patients receiving steroids and azathioprine required
careful monitoring for signs of early infection and the
presence of organ rejection. Progressive reduction in
haemopoietic production leads to thrombocytopenia and
leucopenia, with the attendant risk of infection (bacterial/
fungal and viral). The major complications of long-term
steroid and azathioprine immunosuppression are out-
lined in Table 25.2.
Thus, considerable clinical skill was needed to avoid
the risks of infection, and in cadaveric grafting, when the
degree of matching between donor and recipient was
often less than optimal, death from infection was the
commonest cause of death in the first 3 months after graft-
ing. In addition, the need to administer steroids continu-
ally became a major limiting factor, particularly in
children, where the complications of steroids can be so
crippling (Table 25.3).
The results of organ grafting using prednisolone and
azathioprine left much to be desired, and so the intro-
duction of ciclosporin into clinical trials in the early 1980s
was an important step forward in the more selective use
of immunomodulation. Not only could steroids be mini-
mized or avoided in some individuals, but also pancyto-
penia was rarely encountered. Nevertheless, ciclosporin
was rapidly found to have its own attendant problems
and difficulties and nephrotoxicity remains a persistent
problem (Table 25.4).
Table 25.4 Side-effects of ciclosporin
Nephrotoxicity
Hepatotoxicity
Tremors, convulsions
Skin problems
Gingival hypertrophy
Haemolytic anaemia
Hypertension
Malignant change
With increasing clinical experience, however, many of
these toxic effects can now be minimized, such that excel-
lent rehabilitation can be achieved and organs can now be
grafted which previously would have been unsuccessful
in the prednisolone and azathioprine era. The overall
results of ciclosporin will be outlined in the individual
sections, but there have been no clinical series in which
the results of ciclosporin have been inferior to the treat-
ment with azathioprine and prednisolone, and for the
most part an improved benefit of between 15 and 20% of
graft survival at 1 year has been reported.
Postoperative monitoring of all patients with trans-
planted organs involves regulation of the immunosup-
pressive regimen, detection of the development of organ
rejection and constant vigilance for signs of infection.
Table 25.2 Side-effects of steroids and
azathioprine
Steroids.
Avascular necrosis of bones
Diabetes
Obesity
Cushing's syndrome
Pancreatitis
Cataract
Skin problems
Psychosis
Azathioprine
8one marrow suppression
Polycythaemia
Hepatotoxicity
Table 25,3 Side-effects of steroids in children
* Growth retardation
* Cushingoid appearance
• Diabetes
• Obesity
CADAVERIC ORGAN DONATION
The concept of the diagnosis of brain death and
increased awareness by both the public and doctors alike
of the need for organ donation have improved the
supply of cadaveric organs for grafting. In the UK, about
half of patients who become organ donors have died
from spontaneous intracranial haemorrhage, although
head injuries and road traffic accidents also provide
donors.
SPECIFIC ORGAN TRANSPLANTATION
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Kidney
Kidney transplantation is now well established as the
most effective way of helping patients with end-stage
renal failure. Despite a significant expansion in the
number of kidney transplants, long waiting lists exist for
those on dialysis awaiting treatment. In the UK an
integrated approach has shown a steady increase in the
proportion of patients treated by transplantation, such
that nearly 50% of patients now have a functioning
transplant.
252
TRANSPLANTATION
25
Patient selection
With kidney transplantation affording the optimal quality
of rehabilitation few patients will be denied the prospect,
although the patient's age and underlying renal condition
may need to be taken into account.
Age. In general, children do very well after trans-
plantation, although infants below the age of 5 years
present a more controversial issue because of the diffi-
culty of management of immunosuppressive agents. The
newer immunosuppressive regimens, however, allow
adequate growth and physical development. The goal for
children must be the establishment of normal renal func-
tion before maturity and to take full advantage of the
growth spurt that occurs at puberty.
While in the early days patients over the age of 55 years
were frequently denied transplantation, many centres
now offer renal transplantation to patients over 65 or
70 years. Patient and graft survival has been very satis-
factory in this group, but immunosuppressive schedules
frequently need to be reduced in the elderly to ensure that
overwhelming infection does not occur.
Renal disease. Renal transplantation is now offered
for many primary and secondary renal conditions result-
ing in chronic renal failure, including glomerulonephritis,
pyelonephritis and polycystic disease. Some types of
autoimmune glomerulonephritis antibodies have been
demonstrated to cause damage to the transplanted
kidney, but this is not a contraindication to transplanta-
tion, as probably less than 10% of grafts will be seriously
injured.
Assessment of potential recipient
Careful review of both the physical and psychological
status of the patient is needed before transplantation, and
factors that may increase the hazards of surgery or
immunosuppressive management require evaluation.
Patients in renal failure frequently suffer from cardiovas-
cular problems (hypertension with left ventricular hyper-
trophy, and coronary artery disease) and the symptoms
are increased by anaemia. There is a high incidence of
peptic ulceration in uraemic patients, and of metabolic
bone disease, causing renal osteodystrophy All these
associated conditions must be optimally treated or con-
trolled before transplantation surgery. Sources of under-
lying or potential infection, such as an infected urinary
tract or peritoneal cavity from peritoneal dialysis, must be
eradicated or treated and the patient's status for viruses
such as hepatitis B, HIV and cytomegalovirus must be
known to minimize activation following immunosup-
pression. Careful surgical review related to previous
abdominal operations, peripheral vascular ischaemia
or the presence of ileal conduits following previous
urogenital surgery needs also to be carefully taken into
account and a surgical plan initiated.
Careful counselling and support are also needed to
ensure that the patient understands and is prepared for
transplantation.
Surgical technique
The technique of renal implantation has remained
unchanged now for nearly 40 years, with the donor
kidney being implanted extraperitoneally in one of the
iliac fossae. The renal artery is anastomosed to either the
internal or the external iliac artery, and the renal vein to
the recipient's external iliac vein. The donor ureter is then
implanted into the recipient's bladder. Over 150 000
kidney grafts have been performed around the world, but
total transplantation rates vary significantly from one
country to another.
Postoperative problems
Monitoring of the kidney allograft is required to detect
signs of rejection, suggested by a reduction in urinary
output and an elevation in serum creatinine, and then
confirmed by biopsy or aspiration cytology. This allows
the prompt recognition of an acute rejection crisis and its
treatment by steroids.
With increased clinical experience the hurdles of acute
rejection and infectious complications can usually be
overcome, and patient survival at 1 year is in excess of
95% in many programmes, with over 85% of kidney grafts
functioning well; however, a steady attrition of renal
grafts will occur over the next 10 years, so that only just
half of all renal transplants will be functioning well at
10 years, with many having been lost from the slow
process of chronic rejection.
Rehabilitation can be spectacular, allowing patients the
freedom to eat without restriction on salt, protein or
potassium, the resolution of anaemia and infertility and
an improvement in their overall sense of well-being.
Renal transplantation in the diabetic patient can be
combined with pancreas transplantation, with implanta-
tion of the whole organ and drainage of the pancreatic
duct into the gastrointestinal tract or the urinary bladder.
Transplantation of isolated pancreatic islets is in its
infancy.
Heart
While the patient afflicted by renal disease has the benefit
of chronic haemodialysis, the individual with progressive
cardiac problems has no life support system and death
invariably ensues unless cardiac transplantation is under-
taken. Initial efforts in the late 1960s by Barnard (1967) led
253
25 ■OPERATION
to a progressive expansion of increasingly successful
programmes. The majority of patients will suffer from
cardiomyopathy, terminal ischaemic cardiac disease or,
more rarely, some congenital form of cardiac disease.
Donor selection must be rigorous because immediate life-
sustaining function is required of the graft.
Orthotopic replacement of the diseased heart has been
the most frequently undertaken procedure, although the
heterotopic placement of auxiliary cardiac implants has
been undertaken. The donor atria are anastomosed to
the posterior walls of the corresponding chambers of the
recipient prior to joining the pulmonary artery and the
aorta.
Postoperative cardiac function is monitored and
endomyocardial biopsy allows histological examination
of heart muscle for ventricular cellular infiltration indica-
tive of acute rejection. While the early attempts at cardiac
grafting resulted in poor overall survival, the situation
has improved remarkably. A 1 year survival of over 85%
and a 5 year survival of 60% of patients with excellent
quality of rehabilitation are most encouraging.
This solid foundation of cardiac grafting inevitably led
to an extension to combined heart and lung transplanta-
tion, primarily for those suffering from pulmonary hyper-
tension, or for some terminal lung diseases, such as cystic
fibrosis or emphysema. If the recipient has lung disease
but a good functioning heart on receipt of a combined
heart— lung graft, the heart from the first recipient can be
implanted into a second cardiac patient - the domino pro-
cedure. As a result of technical advances, transplantation
of single lung is now possible. Because of the risk of infec-
tion in the implanted lungs, immunosuppressive man-
agement is critical. Sputum cytology and even lung
biopsy may be needed to differentiate infection from
rejection. In spite of this, the Stanford University Series
now reports 2-year survival of over 60% in heart-lung
recipients.
Liver
Although the first attempts at liver transplantation were
made in the early 1960s, the formidable technical, preser-
vation, immunological and organ availability difficulties
meant that it was only in the early 1980s that successful
programmes were established. The majority of adult
patients coming to liver grafting have extensive cirrhosis
(primary biliary cirrhosis, chronic active hepatitis and
hepatitis B) or, less frequently, primary liver cancer. In the
paediatric group the most common indication for liver
transplantation is biliary atresia.
The liver is particularly susceptible to ischaemic injury
and the ability to harvest and store livers for only a few
hours led to an extremely complex surgical procedure,
undertaken often in the most difficult emergency situations.
The liver is placed orthotopically after removal of the
diseased organ, and veno venous bypass is employed to
reduce the physiological changes during the anhepatic
phase. Improvements in organ preservation (principally
the introduction of the University of Wisconsin solution)
mean that livers can now be stored for 12-14 h and trans-
ferred from one country to another. The evidence that
tissue matching is important in liver grafting has yet to be
fully established, but, as in other forms of transplantation,
this may prove to be the case.
Patients coming to liver grafting are frequently criti-
cally ill with multisystem failure, and the complexity of
the operation has inevitably meant that technical failures
have been frequent. In spite of this, results have con-
tinued to improve, and with nearly 30 000 liver trans-
plants performed in Europe and 1 year survival of over
85%, liver transplantation is increasingly being estab-
lished as one of the most effective modalities of treatment
for liver disease. In some groups the results have shown
even more impressive improvement. Infants and children
with biliary atresia undergoing grafting stand a greater
than 90% chance of 1-year survival, with more than 75%
well at 5 years. The longest survivor is now over 25 years
after transplantation.
The major limiting factor in liver grafting now is donor
availability and, while in the UK some 650 grafts were
performed in 2001, the need is probably double that. The
most acute shortage is of paediatric organs, and often a
larger liver has to be divided and only part transplanted
into a child. Recently partial lobe donation has become
possible from live donors, usually a parent, especially in
countries where cadaveric programmes are not available,
such as Japan. This same approach is also being explored
in adults.
Other organs
Pancreas transplantation is increasingly being undertaken
in diabetics, often in kidney failure who need a kidney
transplant. The techniques developed allow the pancreas
to drain through the bladder and >85% of patients are
insulin free at 1 year. It remains to be confirmed that the
improvement in carbohydrate control will improve the
diabetic complications, but sugar control is excellent.
In children, programmes of intestinal transplantation
are also developing with encouraging results, allowing
the children to come off total parentral nutrition and
resume normal feeding.
ETHICAL ISSUES
The development of transplantation in the 1950s and
1960s caught not just the imagination of the medical
254
TRANSPLANTATION
25
profession but that of the public as well, and led to the
reappraisal of fundamental beliefs in many areas. The
concept of death was challenged, from the traditional one
of the cessation of the heart beat to that of the concept
of brainstem death, and wide public and professional
debates ensued. Death, the great taboo of the 20th century,
was addressed in a new, fundamental way. The majority
of countries enacted legislation or medical guidelines
identifying new criteria which would allow more effec-
tive recognition of an individual's incapacity to regain
essential and vital functions. Some of these issues were
challenged in courts of law and were often widely
reported in the media.
Thus ethical and moral issues were raised from the very
outset of organ grafting. With the increasing success of
organ transplantation these pressures have grown. The
rights of the individual to dispose of his or her own
organs as they wish has been a matter of debate, and the
profession has loudly condemned the commercialism
which is in danger of entering clinical practice. The pur-
chase or sale of organs is now condemned by almost all
international transplantation organizations.
Should a living individual during his or her lifetime
voluntarily donate an organ to another? The first suc-
cessful grafts between identical twins from within a
family were clearly perceived to be an act of great charity
and compassion. Living-kidney grafting in the USA
accounts for more than a third of all grafts, but should
such altruism be permitted between non-family
members, or those in whom a loving and caring bond
does not exist? These new issues continue to be addressed
by society.
One other issue has particularly focused on cardiac and
liver transplantation and this relates to the consumption
of economic resources for an individual. In the UK the
cost of renal transplantation in total is approximately
£8000-10 000, whereas the cost of dialysis per year per
patient approaches £15 000. While renal transplantation is
clearly the most cost-effective way of dealing with renal
failure, compared with some other forms of medical and
surgical treatment and perhaps healthcare initiative, it is
seen as being expensive.
Cardiac and liver transplantation can equally be seen to
consume a large amount of health resources and may be
given a low priority in some health systems.
The development of live related liver lobe donation is
also giving rise to some concerns because of the potential
risk of such major surgery to the donor.
Each new development in science and clinical medicine
raises its own issues, which need to be addressed, and, as
these modalities of treatment spread to other countries,
different cultural approaches may be required. It will be
for the individual community to decide whether such
treatments are appropriate for its members and to what
extent resources can be made available.
Clinical organ transplantation has evolved rapidly
over the last 25 years, affording treatment to many thou-
sands of patients who would otherwise be dead or endur-
ing an existence of chronic illness. Further advances are
sought in the fight against the recipient immune response
and to procure donor organs of the highest quality, thus
enabling even more patients to experience the increasing
benefits of transplantation.
Summary
• Successful whole organ transplantation
has depended on a number of advances in
understanding of infection and
immunosuppression.
• Awareness of the public and of doctors
has increased the supply of cadaveric
organs but a severe shortage remains so
that many patients who could benefit will
die while awaiting a donor organ.
• Results have improved because of better
monitoring and management, rather than
from any technical changes.
References
Barnard CN 1967 The operation. A human cardiac transplant:
an interim report of a successful operation performed at
Groote Schuur Hospital, Cape Town. South African Medical
Journal 41: 1271-1274
Borel JF, Feurer C, Gutter HU, Stahelin A 1976 Biological effects
of cyclosporin A: a new antilymphocytic agent. Agents and
Actions 6: 468-475
Calne RY 1960 The rejection of renal homografts: inhibition in
dogs by 6-mercaptopurine. Lancet i: 417-418
Gibson T, Medawar FB 1943 The fate of skin homografts in
man. Journal of Anatomy 77: 299-309
Hitchings GH, Elion GB 1959 Activity of heterocyclic
derivatives of 6-mercaptopurine and 6-thioguanine in
adenocarcinoma 755. Proceedings of the American
Association for Cancer Research 3: 27
Medawar PB 1 944 Behaviour and fate of skin autografts and
skin homografts in rabbits. Journal of Anatomy 78: 176-199
Mitchison NA 1953 Passive transfer of transplantation
immunity. Nature 171: 267-268
Murray JE, Merrill JP, Harrison JH 1955 Renal
homotransplantation in identical twins. Surgery Forum
6: 423^26
Schwartz R, Dameschek W 1959 Drug induced immunological
tolerance. Nature 183: 1682-1683
255
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257
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Pathogenesis of cancer
P. D. Nathan, D. Hochhauser
Objectives
Recognize that gene defects cause cancer.
Understand the processes involved in
normal cell cycle control.
Understand the genetic events leading to
loss of cell cycle control.
Appreciate the genetic background to
invasion, metastasis and angiogenesis.
Recognize that this understanding is
leading to new therapeutic approaches.
INTFtoDU^
Cellular processes are controlled by the products of gene
expression. A gene is a unit of inheritance that carries
information representing a protein; it is a genetic store-
house, a stable information packet, transmitted from one
generation to the next. Information flows from DNA to
RNA (transcription) to proteins (translation). Some genes
have key functions controlling cell growth, and, if these
are damaged, abnormal cell proliferation may result.
Deregulation (freedom from control) of genes, either
inherited or acquired, may result from mutations (Latin
mutate = to change), deletions and other mechanisms of
gene 'silencing'. This may result in a breakdown of
normal cell cycle control, including the avoidance of pro-
grammed cell death - apoptosis (Greek apo- - from +
piptein = to fall).
Cancer (Latin = crab, German = krebs; possibly from
the appearance of the distended veins extending out-
wards in all direction, like crab's legs) is now a major
cause of death in the United Kingdom. Cancers develop
because of genetic alterations, including the acquisition of
power to invade normal structures and to metastasize
(Greek meta = often implies change + stasis - a standing).
As our understanding of these processes develops, we
can identify novel therapeutic targets, improving anti-
cancer treatment.
CJl L CYCJUE C<WT^
1. Successful cell cycle control is critically important.
Fortunately, a number of key regulatory elements have
evolved that reduce the likelihood of uncontrolled cell
growth. Regulatory signals may be positive or negative.
The normal cell cycle is controlled by a balance of positive
and negative signals from both outside and inside the cell.
2. A normal gene that exerts a positive growth signal is
a proto-oncogene (Greek protos = first, primitive; onkos =
tumour). If it is damaged, it gives an abnormally increased
'on' drive to cell growth and is termed an oncogene if such
an alteration results in development of a cancer cell.
3. A normal gene that exerts a restraining effect on cell
growth is a tumour suppressor gene. If it is damaged or
lost, the cell is deprived of the 'off signal.
4. The activation of oncogenes and absence of tumour
suppressor genes deregulates (frees from restraint) cell
cycle control.
5. Under normal circumstances, environmental infor-
mation from outside the cell is relayed to the cell via cell
surface receptors which may bind growth factors such as
epidermal growth factor (EGF), inhibitory factors or com-
ponents of the extracellular matrix (ground substance).
When a molecule such as a growth factor (a ligand, from
Latin Hgare - to bind) unites with its receptor, this
receptor-ligand binding induces a change of form in the
receptor. This in turn activates an enzyme, for example a
tyrosine kinase. Tyrosine kinases function within cells to
attach phosphate groups to the amino acid tyrosine -
phosphorylation. This triggers an intracellular signalling
cascade, mediated via protein-protein interactions,
inducing enzyme activity. The result is a change in gene
expression, producing an increased cellular proliferation.
Tyrosine phosphorylation is thus an early event in a
complex signalling system. Depending upon the incom-
ing information, the cell may respond in a variety of
ways. If the ligand is a growth factor, the cell enters into
the S phase of the cell cycle (Fig. 26.1).
6. Once a resting cell is in G it can remain quiescent
and viable, yet it can reinitiate growth after latent periods
of months or years. When a resting cell enters the late G :
259
MALIGNANT DISEASE
GO
(quiescence)
Growth
factors
mitogens
Inhibitory
V>x (actors
S phase
(DNA synthesis)
M phase
(mitosis)
Fig. 26.1 Resting or quiescent cells (G ) can pass into
the cell cycle by the action of growth factors. Once past
the restriction point R, they are committed to progress
through S phase where DNA synthesis occurs. The stars
indicate checkpoints that allow the fidelity of the
process to be monitored and errors dealt with.
phase it passes a restrictive checkpoint where any
damage to DNA is detected. If no abnormality is detected,
the cell is committed to DNA synthesis (Fig. 26.1). There
are further checkpoints at S (synthesis), G 2 (second gap)
and M (mitosis) phases to ensure the fidelity of the DNA
synthetic process.
Key point
Checkpoint controls ensure that, if an error is
detected, further replication is prevented.
7. Repair of an abnormality in the DNA may be poss-
ible but, if not, the cell undergoes programmed cell death.
Apoptosis is the final common pathway for a large
number of cellular insults and allows cells to avoid
passing damaged DNA sequences on to the next gener-
ation. Under normal circumstances apoptosis is avoided
by a combination of the presence of antiapoptotic signals
and the absence of proapoptotic signals.
ABNORMAL OE^^
1 . Oncogenes and suppressor genes have been identi-
fied at many of those stages of cell cycle control described
above.
2. Cancer cells escape reliance on exogenously pro-
duced growth factors to stimulate their growth. They may
do this by (Fig. 26.2):
a. Overproducing growth factors which are released
into the cellular microenvironment and which auto-
stimulate the cancer cells
b. Overexpressing growth factor receptors
c. Expressing mutated or truncated receptors that give
constant 'on' signals
d. Expressing altered components of the downstream
signalling pathway.
3. Cancer cells also avoid normal antiproliferative
signals. For example, the effects of the antigrowth
signal, transforming growth factor beta (TGFp), can be
downregulated at the receptor level or within its signal
transduction pathway (Latin trans = across, beyond +
ducere - to lead; the path followed by the signal) in a
Fig. 26.2 How cells escape reliance on external growth
factors: a, overproduction of growth factors;
b, upregulation of growth factor receptors;
c, constitutive signalling by mutated receptor;
d, constitutive signalling by mutated components of
signal cascade.
260
PATHOGENESIS OF CANCER
26
similar way to those growth factors described above.
Many antiproliferative signals ultimately appear to exert
their action through the retinoblastoma protein (Rb)
which inhibits E2F transcription factors; these are pro-
teins with DNA-binding motifs. They bind to specific
nucleotide sequences - promoters close to the initiating
codon of each gene, thus controlling transcription. They
control the expression of many genes involved in cell
cycle progression and DNA synthesis. Mutations in the
Rb gene, the archetypal tumour suppressor gene, de-
regulate this pathway, allowing E2F transcription factors
to exert their effect by stimulating the release of genes
involved in proliferation.
4. Avoidance of apoptosis is a central feature of most,
if not all, cancers. A variety of pro- and antiapoptotic
signals converge on a final common pathway of mito-
chondrial release of cytochrome c, the pigment that trans-
fers electrons in aerobic respiration. Mitochondria (Greek
mitos = thread + chondros = granule) are cytoplasmic
organelles involved in cellular respiration. Apoptosis is
regulated by members of the bcl-2 gene family, an onco-
gene, described initially in B-cell lymphoma, which pre-
vents cell death by apoptosis. The effect of increased
expression of bcl-2 may in part explain resistance to the
effect of chemotherapy in cancer cells that express high
levels. The most common proapoptotic signal lost in car-
cinogenesis is the p53 suppressor gene, which is mutated
in over 50% of human common solid tumours. Under
normal circumstances, p53 plays a key role in detecting
DNA damage, and initiating cell cycle arrest and DNA
repair.
New blood vessel
formation (angiogenesis)
=5S
Metastatic spread
o
%
o
o
o
c
c
©
7
o
O
O
O
Basement
membrane
Blood vessel
Fig. 26.3 Cancers must traverse the basement
membrane before infiltrating blood vessels,
metastasizing to distant sites and stimulating new blood
vessel growth if they are to spread and grow.
E
Key point
Loss of cell cycle regulatory control is a critical
factor in the development of cancer cells and
resistance to treatment.
ANGIOGENESIS AND METASTASIS
1. The features that differentiate benign from malig-
nant growth are invasion and metastasis. Cells must
traverse the basement membrane and other extracellular
boundaries and then attract a blood supply to support
tumour growth (Fig. 26.3). Changes in expression of
cell-cell adhesion molecules (CAMs) and cell-matrix
adhesion molecules (integrins) are thought to be pivotal.
Loss of E-cadherin function, a CAM facilitating epithelial
cell-cell interaction, occurs in many epithelial tumours.
Integrin expression is switched on to allow movement
through local extracellular matrix and adhesion to distant
matrix, and enzymes which digest matrix components,
matrix metalloproteinases (MMPs), are expressed and
digest local stroma (connective tissue framework), facili-
tating movement of the cell through the extracellular
matrix.
2. In addition to loss of adhesion, previously static,
specialized cells may lose their special function, their
ability to differentiate, and migrate. Many solid tumour
cells attract fibroblasts, which lay down collagen around
them. It is the appearance of the resulting radiating
strands of fibrous tissue that makes cancers resemble a
crab's body - the primary tumour, with claws - the result
of cancer cell migration, hence the name of cancer.
Key point
• Angiogenesis is a key factor in development of
tumours.
261
26 -
MALIGNANT DISEASE
■■-■■■ L. -,■■ ,
3. Control of new blood vessel formation, angiogene-
sis, is dependent upon the interaction of pro- and anti-
angiogenic stimuli. Vascular endothelial growth factor
(VEGF) is upregulated in some tumours, and in animal
models VEGF inhibitors have antitumour activity. The
angiogenesis inhibitor thrombospondin has also been
shown to be downregulated. Other components of this
process are being identified and may offer future thera-
peutic targets.
4. Although cancer cells are thought of as being rapidly
dividing cells, the rate of division of many cancers is not
as high as in many normal tissues such as the gut mucosa,
bone marrow and skin. However, the loss of apoptosis
and the reduction of telomeric erosion mean that the
malignant cells have increased survival, provided that
they retain their blood supply.
ACQUISITION AND ACCUMULATION
OF GENETIC DAMAGE
1 . Damaged genes may be inherited through germline
DNA (see Ch. 40). This is responsible for cancer families
that have a preponderance of cancer often presenting at
an early age. A variety of genes have been identified that
are associated with an inherited high risk of cancer. For
example, mutations, and consequent loss of function of
the tumour suppressor genes BRCA-1 and BRCA-2, occur
in breast and ovarian cancer, and of the familial adeno-
matous polyposis (FAP) gene in some forms of inherited
colon cancer.
2. The majority of cancers are sporadic - scattered,
occurring casualty and caused by derangement of somatic
(Greek soma = body) genes. It is now well recognized that
there is a latent period, sometimes of many years,
between the time of the initiating influence and the devel-
opment of the cancer. Cancers do not result from a single
mutation but from a stepwise accumulation of abnormali-
ties. The fact that cancers arise more commonly as age
increases is in keeping with the accumulation of muta-
tions with time. Those who inherit a germline risk factor
that affects every cell in their bodies are already primed,
awaiting further stepwise mutations.
3. Environmental factors are recognized as important,
as the incidence of cancer arises between different stable
populations and between stable populations and
members who migrate elsewhere. For example, when
Japanese migrate to Hawaii the incidence of gastric carci-
noma is reduced, and is even further reduced if they
move to the USA. The best known environmental cause
of bronchial cancer is cigarette smoking. Gastric cancer is
associated with a diet rich in smoked foods; mesothe-
lioma is closely linked to contact with asbestos; aflatoxins
released by the fungus Aspergillus flavus are implicated in
hepatocellular carcinoma.
4. Electromagnetic and particulate radiation act by
increasing mutations. X-rays initiate them, especially in
the bone marrow; ultraviolet light from solar radiation
affects the skin.
5. DNA oncogenic viruses act by encoding proteins
that interfere with growth regulation (Table 26.1).
Epstein-Barr virus (EBV), may promote cancers, includ-
ing Burkitt's lymphoma and nasopharyngeal cancer.
Hepatitis B virus (HBV) is associated with hepatocellular
cancer. Human papillomavirus (HPV) is associated with
cervical carcinoma.
r.
^— tatri" i
Table 26.1 Carcinogenic agents
Agent
Viruses
Human papilloma virus (HPV)
Hepatitis B and C viruses (HBV, HCV)
Epstein-Barr virus (EBV)
Human T-lymphocyte virus 1 (HTLV-1)
Chemical carcinogens
Cigarette smoke
Asbestos
Nickel, chrornates, arsenic
Aromatic amines
Polyvinyl chloride
Afiatoxin
Radiation
Ionizing radiation
Ultraviolet radiation
Tumour type
Cervical cancer
Hepatocellular carcinoma
Burkitt's lymphoma, nasopharyngeal cancer
AduftT-cell leukaemia and lymphoma
Lung, laryngeal and bladder cancer; some increased risk of many others
Mesothelioma
Lung
Bladder
Angiosarcoma of liver
Hepatocellular carcinoma
Leukaemia, breast cancer, thyroid cancer
Melanoma, basal cell and squamous cell cancers of skin
262
PATHOGENESIS OF CANCER
26
6. RNA retroviruses, single-stranded viruses, initiate
copies into DNA pro viruses. They do not appear to cause
human cancers directly but human immunodeficiency
viruses (HIV) are associated with Kaposi's sarcoma.
7. Some substances are believed to initiate cancers not
by causing mutations directly but by increasing cell
growth and turnover, thus increasing the opportunities
for mutations to occur. Alcohol abuse may act by causing
chronic liver inflammation, producing high liver cell
turnover. Oestrogen is a stimulant for breast and endome-
trial cell multiplication.
8. Some substances do not initiate cancer if given first,
but if given repeatedly following mutation from an ini-
tiator they induce cancer development. They are called
promoters.
9. Parasites may be involved in the development of
cancer, notably the liver fluke (Schistosoma spp) and
Clonorchis sinensis, which causes bladder cancer.
Key point
• Most cancers are generated by factors in the
environment, not by inherited gene mutations.
10. Point mutations, deletions (a portion of a chromo-
some is lost) and translocations (a chromosome segment
is transposed to a new site) all occur and they are all
capable of interfering with normal gene function.
11. Every gene exists as two copies or alleles (a short-
ened form of allelomorph: Greek allelon - of one another
+ morpke = form; one of two or more alternative forms of
a gene). Mutation of only one allelle of a proto-oncogene
may result in oncogenesis if it produces much variation
of the patient's oncogenic phenotype. The phenotype
(Greek phainein = to show + typtein - to strike) is a struc-
tural or functional characteristic resulting from combined
genetic and environmental activity. Damage is required to
both allelles of a protosuppressor gene if a tumour sup-
pressant effect is to be overcome. This was described by
Knudson in his 'two-hit hypothesis' (Fig. 26.4).
12. Given the complexity of the biological processes
that must be overcome for a cell to exert a malignant
phenotype, it can be seen that damage to a number of
critical genes is required. This "multi-hit hypothesis' was
Hereditary
retinoblastoma
RB
Sporadic
retinoblastoma
Germline mutation ^^
rb
X •
RB
RB
Nv
RB
Somatic
mutation
\
\
RB
Somatic
mutation
rb
X X
rb
rb
X •
RB
rb
*
2nd somatic
mutation
rb
Fig. 26.4 Knudson's two-hit hypothesis. RB, normal
retinoblastoma gene; rb, mutated gene. Patients who
inherit (i.e. in the germline) one defective (mutated)
copy of the gene have a high chance of acquiring a
somatic mutation at an early age, resulting in loss of RB
function. Patients who inherit two normal genes require
two somatic mutations, resulting in sporadic disease
occurring at a later age.
described by Vogelstein, who argued that the progression
from premalignant to malignant lesions seen in colorectal
carcinoma is associated with the accumulation of key
mutations in oncogenes and suppressor genes (Fig 26.5).
This model is now generally accepted as occurring in
many cancers.
13. It would be unlikely for a normal cell with intact
DNA repair machinery to accumulate the significant
amounts of genetic damage required to exert a malignant
phenotype. The fact that cancer cells accumulate exten-
sive DNA damage may be a reflection of their damaged
DNA repair mechanisms and genomic instability.
APC Ki-ras smad4
p53 E-cadherin
Normal
colonic
Small Large
►* adenoma +- adenoma ►
Pre-malignant Colorectal
changes *■ carcinoma ►
Invasion
epithelium
Fig. 26.5 The multi-step pathway to colorectal cancer. The accumulation of 5-10 mutations in several tumour
suppressor genes or oncogenes over a lifetime results in cancer.
263
MALIGNANT DISEASE
Summary
• Do you understand the genetic damage to
those genes responsible for normal cell
cycle control and cell behaviour that result
in cancer?
• Do you realize that multiple events, in a
number of oncogene and suppressor gene
activities, are required for carcinogenesis?
• Can you understand why therapies are
targeted to gene products responsible for
carcinogenesis?
M Further reading
Hanahan D, Weinberg RA 2000 The hallmarks of cancer. Cell
100: 57-70
Kinzler KW, Vogelstein B 1996 Lessons from hereditary
colorectal cancer. Cell 87: 159-170
Sporn MB 1991 The war on cancer. Lancet 347: 1377-1381
264
Principles of surgery for
malignant disease
P. J. Guillou, I. A. Hunter
Objectives
• Appreciate the importance of histological
diagnosis.
• Realize the multidisciplinary implications
of management.
• Accept that surgery may be valuable even
when cure is no longer possible.
INTRODUCTION
In 2000 malignant disease was responsible for 151 200
deaths in the UK, a figure that accounts for 25% of all
registered deaths (Cancer Research UK). Tables 27.1 and
27.2 indicate the contribution of different types of malig-
nant disease to both cancer incidence and cancer-related
mortality. Over the last 50 years there have been major
Table 27.1
The most common cancers in 1997
Males Females
Lung
Prostate
Breast
Colorectal
24 440 (19) 14 430(11)
21 770(17)
38 000 (29)
18 130(14) 16 180(12)
Values in parentheses are percentages of total
malignancies registered.
Table 27.2 Gastrointestinal cancer deaths, 2000
Males
Females
Oesophagus
Stomach
Large bowel
Pancreas
4300
4060
8540
3370
2G20
2530
7730
3530
improvements in the survival rates of some solid
tumours, but for many the prognoses remain poor and
largely unchanged (Fig. 27.1).
Despite recent advances in the use of adjuvant therapies
(Latin ad - to + juvare = to help) such as chemotherapy and
radiotherapy, surgery remains the main modality of treat-
ment for many solid organ tumours, including cancer of the
breast, lung, urogenital tract and gastrointestinal tract. You
must fully assess the tumour and the patient before decid-
ing on surgical intervention. This demands detection, his-
tological diagnosis, staging and consideration of the role of
other adjuvant interventions. The process is best planned,
carried out, monitored and followed up in cooperation
with a multidisciplinary team including radiologists,
pathologists, radiotherapists and medical oncologists.
ASSESSMENT
Patient assessment is a vital part of operative planning.
Establish a pathological diagnosis and the extent of
100%
&
«<>
^
V
* </ jr <f
Fig. 27.1 Changes in 5 year survival rates from
1971-1975 to 1991-1993 according to cancer type.
(Source Office for National Statistics, Cancer Trends in
England and Wales 1950-1999).
265
27
MALIGNANT DISEASE
spread of the disease prior to operative intervention, as
these factors have a major influence on the treatment you
can offer an individual patient. Assess the patient's
physiological and psychological status; as in all surgery
they impact on the extent of the operative intervention
that you can safely consider.
Pathological diagnosis and tumour grading
Before considering operative intervention obtain a biopsy
specimen for histological analysis to confirm the presence
of malignant disease and indicate its expected behaviour.
Biopsies of gastrointestinal and urogenital tumours can
usually be obtained by luminal endoscopy. For most solid
organs, biopsy specimens can be obtained using needle core
biopsy or fine needle aspiration cytology, if necessary under
ultrasound or radiological guidance or at laparoscopy.
Histological grading helps predict the behaviour of a
neoplasm based on its histological appearance. Grading
systems focus on the apparent differentiation status of the
tumour. Simple histological grading has poor prognostic
value and is an unreliable guide to treatment. Advances
in molecular biology now allow specific molecules to be
identified that more accurately predict tumour behaviour
and response to available treatment.
Immunohistochemical detection of oestrogen receptors in
breast cancer tissue is a good example of the predictive
value of identifying a molecular marker, as it gives the
probable response of the tumour to oestrogen antagonists
such as tamoxifen. In the future, molecular grading will
increase in value.
Tumour staging
Staging often has a direct impact on the extent of surgery
that must be performed to eradicate malignant disease, or
may indicate that curative resection is not possible and
that only palliative (Latin palliare = to cloak) procedures
are worth considering.
imaging (MRI), conventional and intraluminal ultra-
sound and [ 18 F]-fluorodeoxyglucose-linked positron
emission tomography (FDGPET) have greatly improved
the quality of preoperative staging (see Ch. 5). Despite
these advances, preoperative staging is by no means 100%
sensitive or specific and accurate staging may still be
possible only at, or after, operative intervention. In many
cases true staging is determined by the histological exam-
ination of resection specimens. Although preoperative
assessment is essential, you must be prepared to alter
your planned interventions in the light of the findings at
operation.
SURGICAL MANAGEMENT
^&^^?^&ift7&&?>
w^^m^^mww^^
The aims of surgery in malignant disease are:
• To remove all malignant cells from the patient to
achieve a complete cure. The complete removal of
tumour is termed an Rq resection.
• To maintain or restore the integrity of tissues in order
to preserve function following tumour removal.
Curative resection may be impossible or unsuccessful
because:
• The tumour has invaded vital, unresectable, local
structures.
• An intra-abdominal tumour has seeded into the peri-
toneal cavity.
• Tumour cells have metastasized into distant organs and
still be undetectable (micrometastasis).
• Tumour cells have metastasized into distant organs and
these deposits cannot be safely removed.
R resection usually involves removing the tissue con-
taining the tumour with an intact covering of unaffected
tissue to leave the resection margins free of disease, to
avoid exposing and shedding viable tumour cells.
Imaging techniques cannot yet detect individual tumour
cells, therefore you must expect undetected local spread.
Key point
• In planning surgical intervention, the staging
of tumours is of greater relevance than
grading.
The tumour, node, metastases (TNM) system describes
the extent of spread and generally correlates well with
prognosis. It is based on the size and local spread of the
primary tumour (T), the presence of lymph node met-
astasis (N) and distant metastasis (M). Imaging modalities
such as computed tomography (CT), magnetic resonance
I I Key point
• Learn how tumours spread, in order to obtain
clear resection margins and avoid local
recurrences (see Ch. 26).
Local invasion
Tumours spread locally into the surrounding tissues.
1. Epithelial gastrointestinal tract tumours often
spread longitudinally in the submucosal layer or laterally
266
PRINCIPLES OF SURGERY FOR MALIGNANT DISEASE
27
through the muscular layers towards the serosa; for
example, oesophageal tumours tend to spread longitudi-
nally in the submucosa beyond the visible luminal limits,
so the longitudinal resection must be extensive to avoid
local recurrence at the resection margins. In contrast,
rectal carcinoma spreads a relatively short distance lon-
gitudinally, so resection margins 3 cm from the tumour
are considered safe.
2. If surrounding tissues are invaded, consider these
for resection, based on the principles outlined in this
chapter. For instance, if gastric carcinoma invades the
body and tail of the pancreas, transverse colon, or
retroperitoneal nodes and spleen, resect them en bloc
(French = in one piece) with the stomach.
Lymphatic spread
Tumour cells also spread within draining lymphatics to
regional nodes and may develop into metastatic foci.
Anticipate this and, where possible, remove local nodal
groups in continuity with the lymphatic connections to
the primary tumour.
1 . Colonic lymphatic drainage is initially via the para-
colic nodes, then through the nodes lying alongside the
supplying arteries and on into the preaortic nodes at the
origin of the superior or inferior mesenteric arteries. The
supplying vessels are removed at their origins in order
to excise as many draining lymph nodes as possible.
Therefore the full extent of colon that is dependent on
those arteries for blood supply must be resected. Rectal
cancers tend to spread laterally in lymphatic vessels
within the pelvic mesorectum. Recognition of this has led
to total mesorectal excision, resulting in a lowering of
local recurrence rate.
2. Lymphatic drainage of the testis is to the para-
aortic lymph nodes (due to their embryological
origin within the abdomen). Testicular tumours are
treated surgically by orchiectomy, an approach that does
not address potential lymphatic involvement; however,
surgical treatment of anticipated lymphatic involvement
is usually not required due to the sensitivity of semi-
nomas to radiotherapy. Following orchiectomy for
seminoma it is standard practice to give adjuvant radio-
therapy to the para-aortic nodes, even in stage I disease
(where no lymphatic metastasis are clinically or radio-
logically evident). Such approaches have resulted in
5 year survival rates approaching 100% in stage I
disease.
3. The main route of lymphatic drainage of breast
tumours is to the ipsilateral (Latin ipse = same) axilliary
nodes.
a. The great American surgeon William Halsted
(1852-1922) described in 1882 the principle of radical
(Latin radix - root; hence, by the roots) mastectomy. The
primary tumour should be removed together with the
draining lymphatics and a wide margin of intervening
tissue in one block.
b. The psychological consequences of radical mastec-
tomy and the development of adjuvant therapies have
introduced alternative treatments. In wide local excision,
the breast tumour is excised with a surrounding cuff of
unaffected tissue. This risks leaving residual undetected
disease in the axilliary nodes and in the breast. It is there-
fore combined with adjuvant radiotherapy to the breast,
and either a sampling, or partial clearance, of the ipsilat-
eral axilliary nodes. This is potentially curative, but can
also be considered as a form of staging surgery; later
examination of the resected breast tissue and nodes may
reveal the presence of residual disease or nodal involve-
ment On the basis of postoperative staging, further
radical surgery or systemic chemotherapy can be planned
if necessary.
c. Sentinel lymph node biopsy (SLNB) offers a further
option instead of axilliary clearance or nodal sampling.
It is based on the principle that the lymphatics will ini-
tially drain to a single node before progressing to further
nodal groups. A tracer molecule such as patent blue V
dye, or radiolabeled technetium, can be injected into the
vicinity of the primary tumour at operation, allowing it
to enter local lymphatics and become concentrated in the
sentinel node. Once the sentinel node has been identified
it is removed and subjected to histological examination.
If the node is free of metastatic deposits then the axilla
can be considered free of disease, as it is unlikely that
more distant nodes are involved. A positive sentinel
node indicates axilliary spread, demanding further
operation or adjuvant therapy. Its role is currently under
investigation in a number of UK randomized clinical
trials.
4. Cutaneous malignant melanoma is another tumour
that commonly spreads to local lymph nodes. Treatment
of the primary tumour again follows oncological princi-
ples and aims to remove the melanoma together with a
clear margin of uninvolved tissue; however, this approach
fails to address possible involvement of local lymph
nodes.
a. Elective lymph node dissection (ELND) of regional
nodes has been advocated in an attempt to reduce recur-
rence in the draining nodal basin. However, in stage I
disease only 20% of patients are found to have histo-
logically positive nodes, and ELND is associated with
increased postoperative morbidity and cost. The practice
of ELND has also failed to emerge as a statistically
significant predictor of improved survival in several
prospective randomized trials.
b. SLNB can also be considered in the management of
malignant melanoma. As with breast cancer its role is still
267
27 _
MALIGNANT DISEASE
controversial, although it has been declared as standard
care for patients with melanoma by the World Health
Organization.
Transcoelomic spread
Tumours within intra-abdominal organs can breach the
serosal covering to reach the peritoneal cavity -
transcoelomic (Latin trans = across + Greek koilos =
hollow) spread - and may there form multiple deposits.
Clearance of all tumour cells is now practically imposs-
ible. This accounts for the poor prognosis associated with
serosal involvement in gastric carcinoma. Bear this in
mind when removing tumours so that you do not spread
or encourage the seeding of primary tumour cells within
the peritoneal cavity.
Haematogenous spread
Tumour cells can gain direct access to the vascular system
through the endothelium of their supplying vessels, or
through lymphatics to major ducts draining into the
bloodstream. They may then form metastatic (Greek meta,
signifying change + stasis = a placing; a change of situ-
ation) tumour deposits, typically in the liver, lung and
bone marrow. These are often undetectable at the time of
surgery and become clinically apparent months or years
after the primary resection. Although metastatic deposits
threaten survival, some are suitable for resection. Of the
50-60% of patients with colorectal cancer who develop
liver metastases, around 25% are suitable for attempted
curative resection, with 5 year survival rates of 27-37%.
Likewise, in selected cases, pulmonary metastases may
also be considered for surgical treatment using solitary
wedge resection, multiple wedge resections or lobectomy.
Five year survival rates of 21-43% have been achieved,
although a high preoperative carcinoembryonic antigen
(CEA) level or lymph node metastases are both predictors
of a poor outcome in these patients.
Palliative procedures
Curative (R ) resection involves the removal of the
tumour and a large amount of unaffected tissue.
Extensive resections increase the short- and long-term
risks of complications; therefore, such resections are
warranted only with the prospect of achieving a cure. If
removal of all malignant tissue is not possible, tumour
recurrence is inevitable unless adjuvant therapy, such as
chemotherapy or radiotherapy, is given to destroy re-
sidual tumour. If this is ineffective, consider a palliative
(Latin palliare = to cloak) procedure if it offers symp-
tomatic benefit.
1 . Oesophageal, gastric, small bowel or colonic obstruc-
tion can often be relieved by palliative resection, bypass or
construction of an external stoma. Malignant oesophageal
or colonic obstruction is often amenable to endoscopic
insertion of a stenting tube, or a self-expanding stent
introduced under radiological control, avoiding open
operation. Intraluminal tumour incursion can be
temporarily destroyed with a laser beam controlled
endoscopically.
2. Despite modern imaging methods it is often difficult
to decide, preoperatively, whether malignant biliary
obstruction is amenable to curative surgery. Potentially,
25% of pancreatic cancer patients and 35% of those with
ampullary carcinoma may survive 5 years following
resection. Alternatively, a plastic stent may be inserted
percutaneously or endoscopically, but it tends to block
and then needs to be replaced. Metal stents are less likely
to block but are more expensive. Consequently, there is
considerable controversy about the management of
malignant biliary obstruction.
3. In some cases surgery may alleviate symptoms or
reduce the need for treatment, even though it does not
affect the outcome. For example, patients with incurable
carcinoma of the stomach or colon may bleed chronically
and require regular blood transfusions. Resection of the
affected tissue stops the bleeding and mitigates the symp-
toms of anaemia.
4. Apart from relieving obstruction-related colic,
resecting locally invasive bowel tumours rarely reduces
pain. Neurectomy occasionally helps but often results in
motor loss. Coeliac axis block is usually more effective
than systemic analgesia in relieving the deep infiltrating
pain of, for example, unresectable pancreatic cancer.
Curative surgery for secondary malignant
disease
Local or locoregional malignant recurrences are not
always irrecoverable.
1. Regional nodal metastases from malignant
melanoma may follow excision from a limb or trunk. If
there are no detectable distant secondaries, block dissec-
tion may produce 20-25% 5 year survival.
2. Recurrent colorectal cancer suspected clinically, or
through regular monitoring of plasma CEA (see Ch. 30)
and liver ultrasound, may be indications for 'second look'
surgery. Locally recurrent colorectal cancer is rarely cured
by further resection but valuable palliation can often be
provided.
268
PRINCIPLES OF SURGERY FOR MALIGNANT DISEASE
27
Reconstructive surgery for malignant disease
Radical excision of malignant disease often demands
subsequent reconstruction, restoration or replacement:
1 . Stomach mobilized and supplied only by the right
gastric and gastroepiploic arteries can be drawn up
to the neck to replace the resected pharynx or
oesophagus.
2. Following mastectomy, a myocutaneous flap of rectus
abdominis or of latissimus dorsi can be used for
reconstruction.
3. Free tissue transfer may be employed, with
anastomosis of the divided supplying vessels to
local vessels, using microvascular surgical
techniques.
4. Lost skin and tissue can sometimes be replaced by
inserting an inflatable tissue expander to stretch the
skin or develop a space. This is then removed,
allowing the skin to be closed. Following mastectomy
a silicone implant can be inserted as a substitute for
the breast.
ADJUVANT THERAPY
to around 2% after two courses of adjuvant chemotherapy
containing cisplatin.
^^m^^^vK^:S^£;ig:i^
Adjuvant treatment is an extra remedy added to the treat-
ment to increase its effectiveness (see Chs 28, 29). When
applied before surgery it is called neoadjuvant (Greek
neos - new - perhaps revived in a new form) therapy.
Examples are preoperative radiotherapy for rectal cancer,
chemoradiotherapy for oesophageal cancer and some
stages of breast cancer. In these cases the intention is to
'down stage' the primary tumour.
Adjuvant therapy may be administered after surgery,
when the histological staging is available. Patients at high
risk of postoperative recurrence can now be identified
and given additional therapy. An example of this is the
administration of 5-fluorouracil and folinic acid to
patients undergoing resection of Dukes' stage C colonic
cancer (Cuthbert Dukes, pathologist at the famous
St Mark's Hospital in London, classified rectal cancers as
'A' if the tumour was limited to the rectal wall, 'B' if it
extended through the wall but without involving
adjacent lymph nodes, and 'O when regional nodes
were invaded). This adjuvant therapy provides a 30%
improvement in 5 year survival compared with surgery
alone.
Postoperative chemotherapy has also proved to be
highly effective in the management of testicular cancer.
Recurrence rates for men with high risk (those with
vascular invasion within the resection specimen) non-
seminomatous germ cell tumours are reduced from 50%
THE MULTIDISCIPLINARY APPROACH
^^^V^P^f^i^^^l^^^^-i
The multidisciplinary approach to cancer management
combines the expertise of pathologists, radiologists,
oncologists, radiotherapists and surgeons. This has
resulted in the development of new treatment protocols
that in the case of some tumours have seen a great
improvement in survival and functional outcome. The
advances in the treatment of osteosarcoma provide a
good example of how different disciplines can work
together in the management of malignant disease.
1. Osteosarcoma is classically a disease of young
adults; it exhibits aggressive local invasion and a propen-
sity to metastasize early. Historically, treatment involved
amputation of the affected limb and achieved survival
rates of only 10-20%. Osteosarcomas are usually con-
tained within a pseudocapsule of reactive tissue around
the primary tumour. Although well-defined anatomical
compartments initially limit their spread, these tumours
do have a tendency to metastasize via the haematogenous
route, mainly to the lungs and other bones. As well as
forming distant metastatic deposits, more local meta-
stases also occur in the form of intramedullary 'skip
lesions' within the same bone.
2. The surgical principles applied to the treatment of
osteosarcoma are in keeping with those outlined within
this chapter. Ideally a tumour is removed in its entirety
with a margin of unaffected tissue. This may have to
include joints and other local soft tissue structures. Such
an approach often necessitated amputation, due to bone
loss or the removal of neurovascular bundles; however,
advances in reconstructive surgery and neoadjuvant
therapies have resulted in the increased success of limb-
sparing surgery and a reduction in the occurrence of
distant disease.
3. A biopsy specimen is usually obtained at open
biopsy by the surgeon planning the definitive operation.
This allows the biopsy incision to be incorporated in the
final resection specimen. Histological examination con-
firms the diagnosis and also grades the tumour.
Osteosarcoma is one example in which grade is a part of
the staging system and therefore has an influence on
treatment protocols.
4. Initial assessment using combined imaging modali-
ties such as CT, MRI and scintigraphic bone scanning
allow accurate assessment of local and distal spread. This
is essential in the planning of surgical intervention. The
269
27 '
MALIGNANT DISEASE
degree of surrounding soft tissue involvement, the iden-
tification of skip lesions and intramedullary spread will
dictate the extent of the resection margin required for
potentially curative surgery. The feasibility of limb
salvage can also be assessed. Although bone and soft
tissue will be lost in order to achieve local control, func-
tion may be restored by the utilization of prosthetic
implants, cadaveric bone allografts, bone autografts and
rotationplasty. In some cases a "down staging' of the
primary tumour can be achieved by using neoadjuvant
chemotherapy. A good response to such therapy may
induce necrosis in the tumour and reduce surrounding
inflammation. This may make a surgeon more inclined to
attempt limb salvage surgery. The use of preoperative
chemotherapy in non-metastatic high grade resectable
osteosarcoma is now standard.
5. Postoperative chemotherapy is employed, even
after a successful resection of the primary tumour, in an
attempt to target micrometastases to distant organs.
Following resection and reconstruction, histological
examination of the resection specimen is used to establish
the tumour's response to neoadjuvant chemotherapy.
The degree of induced tumour necrosis has been shown
to be a good predictor of clinical outcome. A poor
histological response after neoadjuvant therapy is often
addressed by modification of the postoperative
chemotherapy regimen.
6. This combined approach to the treatment of
osteosarcoma has resulted in a reduced amputation rate
and an improvement in long term survival rates to over
60%.
Summary
Do you recognize that clinical assessment
of patients with suspected malignant
disease is still paramount?
Why does early diagnosis improve the
prognosis?
Can you reason why emergency
intervention carries a poorer outlook than
elective surgery?
Why is it inappropriate to plan operative
treatment of malignant disease in
isolation from other modalities?
Why is it imperative to make a tissue
diagnosis before embarking on ablative
operation for suspected cancer?
What can surgical operation offer patients
when malignant disease has extended
beyond curative resection?
Have you made a decision with the
patient, or for the patient? (see Ch. 14).
Can you offer palliation if you cannot cure
cancer, or if it recurs following resection?
Taylor I, Cooke TG, Guillou PJ 1996 Essential general surgical
oncology. Churchill Livingstone, Edinburgh
270
Principles of radiotherapy
/?. A Huddart
Objectives
Understand the physics and biology of
radiation, determining how radiotherapy is
used.
Understand the process of delivering a
course of radiation.
Recognize the role of radiotherapy
treatment in modern oncology, with
emphasis on its interaction with surgical
oncology.
Understand the basis of radiation
side-effects and how they may interact
with surgical treatment.
beam produced by a linear accelerator has several proper-
ties that make it well suited for present day radiotherapy:
1. The greater penetration of the 7-rays means that a
high proportion of the dose applied to the body surface
reaches the tumour.
2. All X-ray beams have a fuzzy edge (the penumbra)
due to the reflection and scattering of the beam by tissues.
High energy X-rays suffer relatively little sideways scatter
as they pass through tissues, and this helps to keep the
edge of the beam sharp.
3. The forward scattering effect is also indirectly
responsible for the point of maximum dose being 1-2 cm
below the skin surface (Fig. 28.1). The skin therefore
receives a low dose and is spared from radiation reac-
tions. It was the high skin doses associated with low
SOURCES OF IONIZING RADIATION
Radiotherapy is the therapeutic use of ionizing radiation
for the treatment of malignant disorders. Natural sources
of radiation include radioactive isotopes which decay
with the production of p-particles (electrons) and 7-rays
(a form of electromagnetic radiation). Originally radium
was used, but over the last 20 years this has been replaced
by safer artificial isotopes such as cobalt-60, caesium-137
and iridium-192, which are generated in nuclear reactors.
Isotopes are used mainly as sources implanted directly
into tissues, such as iridium needles in the treatment of
carcinoma of the tongue, or inserted into a cavity, for
example caesium sources inserted into the uterus and
vagina for the treatment of carcinoma of the cervix.
Radioactive isotopes may also be given systemically, such
as iodine-131 in the treatment of thyroid cancer.
External beam radiotherapy was revolutionized in the
1950s by the advent of mega voltage treatment machines;
initially cobalt machines and later linear accelerators. The
linear accelerator generates a stream of electrons which is
accelerated to high speed by microwave energy before
hitting a tungsten target. This interaction results in the
emission of high energy X-rays. The high energy X-ray
Or
cm 10
15
20
Fig. 28.1 Dose distribution of a linear accelerator. Note
the maximum dose is below the skin surface and 65% of
the applied dose is present at 10 cm.
271
28
MALIGNANT DISEASE
energy X-ray machines that in the past caused the uncom-
fortable skin reactions and limited treatments of deep-
seated tumours.
In addition, cyclotrons can be used to produce ionizing
beams of heavier particles such as neutrons or protons;
however these machines are yet to find a place in routine
clinical practice.
ACTIONS OF IONIZING RADIATION
^^^■te^v^^^ym^^^^fftfr
X-rays (from linear accelerators) and -y-rays (from iso-
topes) are both forms of electromagnetic radiation and are
biologically indistinguishable. High energy X-rays consist
of packets of energy (photons) which interact with the
molecules of body tissues to cause ionization and release
electrons of high kinetic energy These electrons cause sec-
ondary damage to adjacent molecules, including DNA,
via an oxygen-dependent mechanism. The resultant DNA
damage is mostly repaired by enzymes in a matter of
hours, but certain DNA lesions are irreparable. In some
normal cell lineages (e.g. lymphoid, myeloid, germ cells)
the DNA damage triggers immediate programmed cell
death (apoptosis). Non-repairable DNA damage causes a
variety of chromosomal abnormalities. This DNA damage
does not stop most cells from performing their normal
physiological functions effectively, but when the cell tries
to divide it dies in the attempt. Thus damage is expressed
when the cell undergoes mitosis, and in fully differenti-
ated cells incapable of further division (e.g. muscle cells)
this damage may never be expressed.
Key points
• Tissues may be severely damaged by irradiation
but appear essentially normal; damage is
expressed only if they are stimulated to divide.
• Response to radiotherapy by tumours may be
delayed, especially in tumours with slow rates
of growth (e.g. pituitary tumours).
There are many data on the respective effects of radio-
therapy on normal tissues and tumours. It appears that
tumour cells may not differ greatly from the cell of origin
in response to single doses of radiotherapy, although
there may be differences in the ability of tumours and
normal tissues to recover from the effects of cell damage.
For example, normal tissues have a greater ability to
respond to radiation-induced cell depletion by acceler-
ated repopulation, an ability which seems to be less devel-
oped in tumours. To eradicate a tumour within the limits
of tolerance of surrounding normal tissues, radiotherapy
must exploit these and other subtle differences in DNA
repair and regrowth of normal tissues.
In external beam treatments, therapeutic advantage is
generally achieved by dividing the total dose of radio-
therapy into small parts over several weeks, a practice
called fractionation. A full discussion of the effects of frac-
tionation is not possible in this chapter, but generally:
1. Reducing the dose per fraction allows certain critical
normal tissues, such as the nervous system, the lungs and
other slowly proliferating tissues, to repair damage more
effectively than tumours.
2. Fractionation over a period of several days or weeks
gives rapidly proliferating normal tissues, such as skin
and gut, a chance to repopulate and hence recover from
radiotherapy-induced damage faster than tumours.
3. Many tumours contain hypoxic areas. As the major
effect of radiotherapy is by an oxygen-dependent mech-
anism, these areas are relatively resistant to radiotherapy.
Each fraction of radiotherapy reduces the number of
tumour cells and allows some hypoxic areas to become
better oxygenated. Fractionation allows this process of
reoxygenation, which may take hours or days to occur
and is thought to make tumours more radiocurable.
The above comments help to explain the empirical
finding that radiotherapy is most effective when given
daily over several weeks. A comparable effect to fraction-
ation is seen with interstitial and intracavity treatments
where a continuous low exposure over several days is
biologically equivalent to multiple small fractions.
The ability to cure a tumour probably depends on being
able to eliminate every clonogenic tumour cell from the
target volume. This is influenced by a variety of factors,
as discussed below.
Size of tumour
A number of factors means that the larger the tumour the
less successful radiotherapy tends to be:
• The larger the tumour the greater the number of cells
present and hence a larger number of fractions will be
necessary to have a high probability of eliminating the
last clonogenic tumour cell. For example, the majority
of 2 cm carcinomas can be controlled by 60 Gy, whereas
a 4 cm carcinoma needs 80 Gy for similar control rates.
• Large tumours may contain large hypoxic areas which
are relatively radioresistant and thus reduce the chance
of cure.
• Large tumours usually need a larger treatment volume
than small rumours. This generally increases the volume
of normal tissue irradiated; the greater the volume of
normal tissue, the higher the chance that a part of that
272
PRINCIPLES OF RADIOTHERAPY
28
tissue is damaged by the radiotherapy, and hence the
normal tissue complication rate rises. To reduce this
complication rate a dose reduction is often necessary,
with a corresponding reduction in the chance of cure.
Radiosensitivity of tumour cells
The commonest histological types of tumour have cells of
similar radiosensitivities (e.g. squamous carcinoma cells
and adenocarcinoma cells). Differences in tumour cure
between these common histological types probably relate
more to differences in tumour bulk, oxygenation and pro-
liferation. There are exceptions, with the cells of some
tumours being more radiosensitive, such as seminoma
and lymphoma, and others being more radioresistant,
such as melanoma, glioma and sarcoma. The reasons for
these differences are not clear. Radiosensitive tumours
may be more sensitive due to a greater tendency to
undergo apoptosis in response to DNA damage, but there
is evidence, at least in vitro, that a variety of other mech-
anisms may have a role; for example, melanoma seems to
be more resistant to radiotherapy due to an increased
ability to repair DNA damage.
Tolerance of normal tissues
The total dose that can be applied to a tumour is limited
by the tolerance of the surrounding normal tissue. This
varies greatly between tissues. If the tumour lies close to
a sensitive organ, such as the spinal cord, then the total
dose that can be safely delivered is much less than if the
tumour lies within muscle or bone, for example. Hence
the chance of cure may be reduced. The dose that can be
applied will also depend on the volume that needs to be
irradiated. A good example of this is the lung. The toler-
ance dose for whole lung to be able to function after treat-
ment is in the region of 20 Gy in 10 fractions of 2 Gy.
Therefore, if the whole lung or large sections need to be
treated, as in selected cases of Hodgkin's disease, this is
the maximal fractionated tolerated dose. However, doses
as high as 60 Gy can be given to portions of a lung, such
as a lobe, because small areas of permanent damage are
acceptable and have little overall effect on lung function.
RADIOTHERAPY PLANNING
Key point
The major principle of radiotherapy is to give
the maximum possible dose to the smallest
volume that will encompass all the tumour.
This volume, termed the treatment volume, consists of:
1 . The macroscopic tumour volume determined from
clinical findings, imaging by, for example, X-rays,
computed tomography (CT) scans and radioisotope
scans, and operative findings, termed the gross
tumour volume (GTV)
2. A biological margin (often 0.5-1 cm) which allows for
microscopic tumour; spread beyond the visible
tumour: the clinical target volume (CTV)
3. A technical margin, usually 0.5 cm to allow for errors
and variability in daily set-up such as that due to
respiratory movements of the patient: the planning
target volume (PTV).
Minimizing these errors and improving quality assurance
is an area of active research. Techniques such as mega-
voltage imaging may enter clinical practice in the future;
in this, an X-ray image of the patient is produced as the
treatment beam passes through the tumour, showing how
well the area actually treated corresponds to the treatment
plan.
Accurately localizing the tumour in the patient is essen-
tial to the success of radiotherapy. In most cases the
tumour cannot be visualized directly and localization
depends on physical examination, imaging and operative
notes. The importance of accurate and detailed operative
records cannot be overemphasized. An operation is a
unique opportunity to visualize the tumour directly. Take
full advantage of this opportunity to describe the extent
of disease and acquire as much additional information as
possible about local pathology. Limited information
invariably leads to larger target volumes, increased radio-
therapy morbidity and reduced cure rates.
Once the radiotherapist has determined the exact size,
shape and location of the target volume the aim is to
encompass the target volume with a radiation dose dis-
tributed as homogeneously as possible. A variation of
under 10% is aimed for and achieved. Single fields are
usually inadequate in this respect, except for superficial
tumours. Opposing two fields at 180° to each other treats
intervening tissue homogeneously. This arrangement is
very simple to plan and is suitable for most low dose pal-
liative and a few radical treatments. Two opposed fields
usually include more normal tissue in the high dose
volume than is strictly necessary (Fig. 28.2). Therefore,
more complex multifield arrangements are normal for
curative treatments to confine the high dose volume more
closely to the target. These arrangements are usually
planned by the cross-sectional target volume from CT
scans of the* patient in the treatment position.
Conventional therapy uses rectangular fields to encom-
pass the target volume. As tumours are not cubes, an
unnecessary amount of normal tissue is included in the
273
MALIGNANT DISEASE
b.
Fig. 28.2 Comparison of the dose distribution of
different field arrangements. The parallel opposed field
arrangement (a) adequately treats the target volume
(the bladder) but gives a high rectal dose. A three-field
arrangement (b) covers the target volume with a much
reduced rectal dose and is therefore preferable.
treated volume. This causes increased morbidity and
limits the doses that can be given (e.g. for pelvic tumours
the dose given is limited by the amount of small bowel
included in the target volume). Conformal therapy uses
new engineering and computer technology to generate
irregularly shaped fields so that tumours can be encom-
passed by high dose volumes that correspond more pre-
cisely to the tumour's shape. A recent randomized trial in
prostate cancer at the Royal Marsden NHS Trust has
demonstrated a reduction in the risk of late side-effects
and has allowed dose escalation which should improve
cure rates (Dearnaley et al 1999).
Directing several beams of radiation accurately to
intersect across the target volume does not necessarily
guarantee an even dose distribution because the X-rays
have to pass through different amounts of tissue on the
way from the entry point on the skin to the target
volume. In addition, lung absorbs less energy than other
tissues because of the air it contains. These potential
sources of dose inhomogeneity (Greek in - not + homos
+ genos = kind; not having the same constituent elements
throughout) within the target volume must be calculated
and compensated for using a number of measures that
alter the beam shape and profile, for example different
weightings on each X-ray beam and the introduction of
wedge-shaped filters which absorb different amounts of
energy across the beam (Fig. 28.3). Production of homo-
geneous dose distributions has been greatly facilitated
by the introduction of planning computers and CT plan-
ning which can visualize and allow for tissue inhomo-
geneities directly. This area continues to develop rapidly,
and in the future more sophisticated means of compen-
sating for potential sources of uneven dose distribution
will come into routine practice, as will more advanced
beam-defining devices.
Once satisfactory dose distribution and treatment plans
have been produced and checked, treatment of the patient
can begin. It is important that treatment is applied in a
reproducible fashion. The patient must be positioned,
lying in a recorded position, with appropriate supports to
maintain stability. Lasers are frequently used to help
establish and monitor patient alignment. If extra accuracy
is desirable, especially in the head and neck region, a light
Fig. 28.3 Treating the breast without compensation for
breast curvature produces an inhomogeneous dose
distribution (a). When this is compensated for by a
wedge filter (b) the dose distribution is improved.
274
PRINCIPLES OF RADIOTHERAPY
28
plastic shell may be used to immobilize the patient. The
machine is then positioned according to skin markings
and recorded settings determined during planning / and
treatment is commenced.
Planning radiotherapy
The radiotherapist:
• Defines the volume to be treated.
• Designs radiation fields to encompass the
volume to be treated. Complex 3 or 4 beam
field arrangements are used for radical
treatment to minimize the volume of normal
tissue irradiated. Irregularly shaped
('conformal') fields are now being used to
further reduce the volume of normal tissue
treatment.
• Produces a radiotherapy plan which allows for
dose inhomogeneity to produce a uniform dose
distribution across the volume to be treated.
In recent years several new techniques have improved the
therapeutic ratio in selected circumstances.
Accelerated radiotherapy
This involves giving multiple daily treatments of the
same size as used in conventional fractionation but given
to shorten the overall treatment time from 6 weeks to less
than 3 weeks. Recent research suggests that clonogenic
tumour cells can proliferate significantly during a treat-
ment course of 6 weeks and this could, theoretically,
reduce the chance of tumour control. Reducing the
overall treatment time could make an important differ-
ence, allowing less time for proliferation and leaving
fewer tumour cells to kill; however, reducing treatment
time also gives normal tissues less time to recover.
Enhanced early skin and mucosal reactions may limit this
approach.
Hyperfractionation
This delivers two or three smaller fractions a day over the
conventional treatment period; the number of treatment
days remains the same but the number of fractions is
increased. Reducing fraction size reduces late tissue
damage, with relatively less effect on tumour control.
This has allowed dose escalation, with an increased
chance of cure, especially in head and neck cancer
(Horiot et al 1992).
CHART (continuous hyperfractionated
accelerated radiotherapy)
This new regimen aims to combine the advantages of
accelerated and hyperfractionated radiotherapy by giving
three treatments a day over a 12 day period with no gaps
- including no breaks for weekends and bank holidays.
Results from a multicentre trial have shown that CHART
improved survival in patients with localized lung cancer
and, to a lesser extent, local control and survival in
patients with head and neck cancer (Dische et al 1997).
Stereotactic radiosurgery
This technique utilizes fixation devices adopted for
neurosurgical practice to localize tumours precisely in
three dimensions, using fiducial (Latin fidere = to trust;
trustworthy) markers. By using arcing radiation beams,
conformally shaped fixed fields or multiheaded cobalt
units (gamma knives), radiation beams can be delivered
to a concentrated area with a high degree of precision.
Particularly applicable to cranial radiotherapy, this
allows a high dose to be delivered to the target but a very
low dose to surrounding tissue. This technique can be
used as a boost after a conventional treatment course,
retreatment of recurrences, or as a sole ablative treatment,
as for arteriovenous (AV) malformations not suitable for
surgery (Brada & Ross 1995).
Conformal radiotherapy
Conformal radiotherapy (see above) is now entering
routine clinical practice. Further technical advances,
including the use of multileaf collimators (Latin col =
together + linea - a line; to make parallel: beam defining
devices allowing irregular shaping of fields), which can
vary during treatment administration, and 'inverse plan-
ning' where the radiotherapist determines what he or she
wishes to achieve and the computer determines optimum
field size, shape, direction and weighting, are likely to
lead to further sophistication in treatment administration,
including treatment of concave or annular shapes. This
should further reduce radiation morbidity, particularly
near sensitive structures such as the spinal cord, optic
chiasm and eye.
ROLE OF RADIOTHERAPY
Radiotherapy may be used in the management of malig-
nant disorders in the following ways:
275
28
MALIGNANT DISEASE
• As primary treatment
• As adjuvant treatment before or after primary surgery
or chemotherapy
• For palliation of symptoms
• As a systemic treatment, either in the form of external
beam total body irradiation or of systemic administra-
tion of a radioactive isotope.
Radiotherapy as primary treatment
When radiotherapy is used as the primary treatment the
aim is to effect cure with the minimum of side-effects. It
is an alternative modality (method) of local control to
surgery (Table 28.1). Radiotherapy, like surgery, is most
effective at controlling small, well-localized and defined
tumours, but has the advantage of preserving normal
function. For many cancers, surgery and radiotherapy are
equally effective modes of treatment and close liaison
between surgeons and radiotherapists is essential if the
appropriate modality of treatment is to be chosen for any
given patient. This choice may vary between patients and
depends on a variety of factors, such as tumour site, stage
and histology, and patient age and performance status.
Choice of treatment is not restricted to either surgery
alone or radiotherapy alone; the patient may be best
served by a policy of initial radiotherapy followed by
planned salvage surgery if this fails, as in many head and
neck tumours, or initial combination therapy.
Radiotherapy may be indicated as the initial treatment
by a variety of circumstances, including:
1. Sites where surgery and radiotherapy are equally
effective but radiotherapy gives better functional or
cosmetic results, as in bladder cancer where radical
radiotherapy gives good results and avoids the
necessity for cystectomy and ileal conduit, or
laryngeal cancer where radiotherapy gives equal
results to surgery but allows preservation of the
voice.
2. Very radiosensitive tumours, such as lymph node
metastases from testicular cancers or early Hodgkin's
disease.
3. Inoperable tumours; occasionally radiotherapy can
be used for attempted cure of brainstem gliomas or
pelvic sarcomas.
4. At sites where operations carry a high
morbidity /mortality and equivalent results are
gained by radiotherapy, as for carcinoma of the
upper or mid-oesophagus.
5. In patients unfit for the radical surgery that would
otherwise be the treatment of choice; for example,
patients with bronchial cancer and chronic airways
disease.
All cases, however, need to be carefully assessed to decide
the appropriate treatment option. In some cases where
radiotherapy would normally be indicated, other factors
Table 28.1 Results of curative radiotherapy
Site
Stage Five year survival {%) Comments
Skin
Alf
90-95
Head and neck
Tongue
Tl
91
Glottis
Tl
90
Other sites
All
30-80
Lung
Conventional
Tl
30
Gastrointestinal tract
Oesophagus
All
9
Anal canal
All
66
Urofogy
Bladder
12/3
34
Prostate
T1/2
80
T3
60
Penile
All
75
Gynaecology
Cervix
IB
85-90
2A/6
61-S5
Endometrium
All
60-65
Vagina
Stage 1
75
Equivalent to surgery. Choice depends on site
50-60% for all stages
Local control rates with salvage surgery used for
local relapse
40% 2 year survival
Equivalent to surgery
Better results than anoperineal resection
Salvage cystectomy for local relapse. Surgery only 28%
5 year survival
Equivalent to surgery
Over 90% cure for stage 1 tumours
Equivalent to surgery in randomized studies
For patients unfit for surgery only
276
PRINCIPLES OF RADIOTHERAPY
28
may make surgery preferable for that patient. For
instance, it may not be possible to apply a radical dose
because of an adjacent sensitive structure; cystectomy
may be indicated if small bowel is adherent to the affected
bladder, precluding a full radical dose without a risk of
severe morbidity. Operation may be preferred, especially
in head and neck cancer, as the tumour may involve bone
or cartilage, risking osteoradionecrosis following radical
radiotherapy
Key points
Radiotherapy is an effective alternative
modality to surgery to obtain local control.
• The choice of radiotherapy versus surgery
often depends on tumour- and patient-related
factors.
• Closely cooperate with the radiotherapist to
achieve an optimum treatment strategy for
each patient.
Adjuvant radiotherapy
For some tumours, preoperative or postoperative radio-
therapy may improve local control. Adjuvant (Latin ad =
to + juvare = to assist) radiotherapy (Table 28.2) achieves
this by controlling microscopic spread beyond resection
margins, tumour spilled at operation or lymph node
metastases. The low tumour burden means that lower
doses than those normally used in radical treatments can
Table 282 Effect of adjuvant radiotherapy (RT)
on local control a
nd/or survival
Site
Stage
Criteria
Results (%)
Comment
No RT
RT
Breast
T1/2 NO
LC
63
88
NSABP randomized trial of
conservative surgery
T1/2 N +
LC
57
94
Radiotherapy
Central nervous system
Astrocytoma
Gd1
S
25
58
Oligodendroglioma
All
10 year S
27
50
Pituitary
All
1 year LC
10
90
RMNHST data
Craniopharyngioma
Incomplete excision
S
35
90
70% survival for complete excision
Lung small cell
Thoracic
Limited stage
2 year LC
23
48
}
Overview of nine randomized
2 year S
16
22
trials*
Cranial RT
Limited stage
2 year LC
2 year S
45
16
84
25
1
f
Danish trial'
Gastrointestinal tract
Pancreas
Operable tumour
2 year S
15
42
GITSG trial (NO RT versus RT with
5-fluorouracH)
Rectum
Dukes' C
LC
65
90
MRC 3rd trial survival advantage
In some series
Gynaecology
Endometrium
Stage 1
LC
88
99
Stage 1
S
64
81
Stage 2
S
20
56
Carotid
Carcinomas
All
LC
62
87
Pleomorphic adenomas
Incomplete excision
LC
76
98
Bladder
T2fT3B
S
28
45
Nonrandomized data
Soft tissue sarcoma
Limited stage
LC
60
75
Review of French experience 1
LC local control; S, survival; NSABP r National Surgical Adjuvant Breast and Bowel Project; RMNHST, Royal
Marsden NHS Trust.
*Warde & Payne (1992).
! Work et al (1996).
: Coindre et al (1996).
277
28
MALIGNANT DISEASE
be employed, with a resultant reduced morbidity, while
obtaining a high rate of local control. If local control is an
important determinant of survival, then this may equate
with an improvement in overall survival. Even if meta-
stases limit survival, adjuvant radiotherapy often has a
valuable role in improving locoregional control and
quality of life. This may be especially important if symp-
toms of relapse cannot be easily controlled, for example
in rectal cancer.
Adjuvant treatment may be given to (1) the site of
primary disease to reduce local recurrence or (2) sites of
potential metastatic spread.
Postoperative radiotherapy gives the radiotherapist the
advantage of having details of the surgical and patho-
logical findings in addition to the clinical and radio-
logical assessments. This allows for accurate staging, and
selection of those patients who will most benefit from
radiotherapy. However, the planning of postoperative
radiotherapy can be more difficult, as the radiotherapist
can no longer directly image the tumour. Accurate oper-
ation notes greatly aid localization of treatment, as does
marking the tumour bed with clips. If it is likely that post-
operative radiotherapy will be given, invite the radio-
therapist to see the patient preoperatively, for example,
before wide local excision of a small breast cancer.
Postoperative radiotherapy is of proven value in reduc-
ing local recurrence at many sites, some of which are dis-
cussed below. At most sites postoperative radiotherapy is
of no proven benefit in prolonging survival after com-
plete resection of the primary tumour.
In selected circumstances, preoperative radiotherapy may
be of value. This has the potential advantage of 'down-
staging' the tumour, potentially allowing an easier or less
extensive operation to be performed, for example in rectal
cancer or limb sarcomas. It may also reduce the risk of
seeding at the time of operation and control microscopic
disease at the edges of the tumour. Certain problems have
limited the usefulness of this approach; foremost is the
fear that radiotherapy increases the surgical morbidity.
However, it is now thought that, as long as the operation
is performed within 4 weeks of radiotherapy, this increase
is minimal with doses of radiotherapy up to 40 Gy. A
further problem is that the downstaging effect of the
radiotherapy makes interpretation of the subsequent
surgical specimen and pathological staging difficult. This
also causes difficulties in comparing different series of
patients, assessing prognosis and giving advice on further
treatment. It is therefore a less established form of treat-
ment, but has been used in bladder cancer, rectal cancer
and sarcomas and, less often, in the treatment of
oesophageal and endometrial cancers (Pollack & Zagars
1996, Graf etal 1997).
Radiotherapy to sites of lymph node spread has been
used in the treatment of many cancers, especially when it
was thought that blood-borne spread followed lymph
node invasion. Increasingly, studies suggest that lymph
node metastasis may be a marker of synchronous blood-
borne metastasis, and at several sites prophylactic lymph
node irradiation has been shown to be of little value in sur-
vival terms, such as in bladder and prostate cancer ( Asbell
et al 1988). Despite this, in a variety of cancers, lymph
node irradiation is of value when initial spread is to lymph
nodes and is an important determinant of survival, as in
head and neck cancers, or relapse-free survival, as in semi-
noma. Prophylactic lymph node irradiation is also justi-
fied in reducing the risk of macroscopic nodal disease
when symptomatic relapse is difficult to salvage. An
example of this is supraclavicular fossa irradiation in axil-
lary lymph node-positive breast cancer. Node relapse at
this site is difficult to salvage and has a high morbidity in
terms of lymphoedema and brachial plexus neuropathy.
The risk of such relapse is markedly reduced by applying
adjuvant radiotherapy.
In a similar fashion, craniospinal irradiation improves
prognosis when central nervous system (CNS) spread is
common, for example, in medulloblastoma and ependy-
momas. Chemotherapy only poorly penetrates the CNS,
and for some otherwise chemosensirive tumours the CNS
may act as a sanctuary site, such as in acute lymphoblas-
tic leukaemia (ALL) and small cell lung cancer. If cerebro-
spinal fluid (CSF) metastases are common, cranial or
craniospinal irradiation is a highly successful form of
prophylaxis. For example, following the introduction
of irradiation, the incidence of CNS relapse in patients with
acute lymphoblastic leukaemia has been dramatically
reduced and it has had a major impact on the chances of
cure in this illness.
Key points
• Adjuvant radiotherapy may significantly reduce
the risk of locoregional recurrence, especially if
the tumour is larger or excision is marginal.
• Accurate preoperative staging and operation
records improve the effectiveness of
radiotherapy.
Palliation
Of all modalities used to treat advanced cancer, radio-
therapy is the most useful for the palliation of symptoms
either from advanced primary or metastatic disease. The
278
PRINCIPLES OF RADIOTHERAPY
28
criteria of success must be in terms of quality of life rather
than survival. The aim is therefore to give sufficient treat-
ment to relieve symptoms without short-term side-effects
for as long as the patient is expected to survive. The trend
is towards short courses delivering a few large fractions of
radiotherapy, thereby achieving maximum symptom relief
with minimal interference in the patient's life. Frequently,
a single large fraction of radiotherapy is all that is necess-
ary to palliate symptoms. For example, most patients with
lung cancer present with disease too advanced for any
radical treatment. Such patients are frequently symp-
tomatic with, for example haemoptysis, dyspnoea, pain or
cough. These are usually well controlled with one or two
fractions of radiotherapy (Bleehen et al 1991). In certain
circumstances in pelvic tumours, or recurrent chest wall
breast cancer, longer fractionated courses to higher doses
are necessary to offer a good chance of sustained symptom
relief. In addition, palliative radiotherapy may be used for
relief of symptoms due to metastases. The treatments of
different types of metastasis are considered below.
Bone metastasis
Symptomatic bone metastases affect approximately 20% of
patients at some stage during their illness. Radiotherapy is
a highly effective means of controlling local pain due to
such bone involvement. Recent work has shown that a
single 8 Gy fraction of radiotherapy will relieve pain par-
tially or completely in 80% of patients 4 weeks after treat-
ment (Price et al 1986). Orthopaedic fixation followed by
radiotherapy should be used to prevent fracture for lesions
with substantial cortical bone erosion. Patients with exten-
sive bone metastases, as are frequently seen in prostate
cancer, obtain good palliation from wide-field hemibody
irradiation given as a single treatment. The other half-body
can be treated 4r-6 weeks later. Approximately two-thirds
of patients will obtain good pain relief from such treat-
ments. An alternative approach is to use a radioactive
isotope (strontium-89) which is taken up by bone meta-
stases. It is given as a simple intravenous injection and
may be repeated. In randomized studies in prostate cancer,
strontium-89 produced pain relief equivalent to local or
hemibody irradiation, with the advantage of lower toxicity
and the appearance of fewer new sites of pain on sub-
sequent follow-up (Quilty et al 1994).
Spinal cord compression
This is an emergency which can cause devastating motor,
sensory and sphincter disturbances. Metastatic disease can
cause cord compression by direct extension from vertebral
disease, epidural deposits or, rarely, intramedullary disease.
There has been no large trial of radiotherapy versus surgery
in the treatment of this disorder, but most series suggest
radiotherapy alone, in most instances, is as effective as
surgical decompression followed by radiotherapy. Surgical
treatment should be considered when there is no diagnosis,
in radioresistant tumours such as melanoma and sarcomas,
where there is evidence of spinal instability or progression
through radiotherapy. Over 70% of patients will achieve
good pain relief and 50% a useful response if treated before
a major neurological deficit develops. Some patients will
regain the ability to walk, but only 10% of total paraplegics
regain useful function (Huddart et al 1997).
Brain metastases
This is a frequent complication of advanced cancer and is
associated with a high morbidity. They are especially
common in lung cancer, breast cancer (10% of all patients
at some stage), melanoma, kidney and colon carcinomas.
They are usually multiple and the prognosis is poor, with
the median survival if untreated being 6 weeks. A 50%
symptomatic response rate to radiotherapy and dexa-
methasone is expected, the radiosensitive tumours such
as small cell lung, breast and colon cancers responding
better than average. A good response to dexamethasone
and good performance status also predict for good
outcome. Frail patients with poor performance status
tend to gain little and treatment may not be indicated in
such patients. Short courses of treatment seem to be as
effective as longer courses (Priestman et al 1996). Patients
with a single metastasis have a better outlook, with a
median survival of 4-6 months, and 30% of patients with
breast cancer survive over 1 year. There is some evidence
that surgical resection followed by whole-brain irradi-
ation is better than whole-brain irradiation only, in
selected patients fit for surgery. Recent work with stereo-
tactic boost (see above) suggests that similar results may
be obtained with radiosurgery (Wurm et al 1994).
Superior venal caval obstruction (SVCO)
SVCO is caused by enlarged right-sided mediastinal
lymph nodes or tumours, especially lung cancers. It
causes engorgement of veins to the neck, cyanosis, facial
oedema and dyspnoea. Following mediastinal radio-
therapy, 70% of patients gain relief within 14 days.
Other indications
Some other indications for palliative radiotherapy are
retinal metastases, skin metastases and lymph node
metastases.
279
28
MALIGNANT DISEASE
Key points
• Radiotherapy is effective at relieving symptoms
of advanced local or metastatic disease.
• Short courses of treatment are usually
sufficient to palliate symptoms.
• Longer courses of treatment are sometimes
justified, especially to obtain locoregional
control.
Radiotherapy for the treatment of systemic
disease
Radiotherapy is generally used to treat local disease.
There are, however, two areas where radiotherapy is used
to treat systemic disease: total body irradiation and
radioactive isotopes.
Total body irradiation
A total body dose of >4 Gy will result in bone marrow
failure. This has limited the usefulness of the technique for
the treatment of malignant disease until the onset of bone
marrow transplantation. Total body irradiation using a dose
of 8-10 Gy as a single dose or a higher fractionated dose is
a highly effective conditioning regimen for the treatment of
leukaemias. It is also being examined in trials in the treat-
ment of other radiosensitive tumours such as lymphomas.
Radioactive isotopes
This technique uses radioactive isotopes which emit
short-range p-particles and /or 7-rays. If the rumour con-
centrates the isotope compared to the surrounding tissues
it will be preferentially irradiated. The best example is the
use of iodine- 131 in the treatment of follicular and papil-
lary thyroid cancer. The malignant tissue takes up and
concentrates iodine, and hence residual tumour is irradi-
ated to a high dose. Using this technique, lung and some-
times bone metastases can be eliminated. Other examples
are the use of phosphorus-32 in polycythaemia rubra vera,
strontium-89 in metastatic prostate cancer (see above) and
m-iodo-benzylguanidine (MIBG) in neuroblastoma.
COMJ^G^ONS >w _
Normal tissue side-effects are due to cellular damage
inflicted at the time of irradiation. This damage is largely
expressed at the time of mitosis, so the sensitivity to and
the expression of this damage depend on the proliferative
characteristics of each tissue.
Acute effects
In some tissues, such as the epidermal layers of the skin,
the small intestine and bone marrow stem cells, turnover
is rapid and damage is expressed early. Skin is the classic
example of such a tissue. Stem cells in the basal layers of
the skin divide; the daughter cells differentiate and move
to the surface over a 2 week period to replace shed cells.
After irradiation, production of replacement cells is
reduced or halted. The epidermis gradually thins and, if
sufficient damage has occurred, epidermal integrity is lost
and desquamation occurs. Recovery will occur over a
period of days or weeks after the end of treatment by sur-
viving stem cells producing enough daughter cells to
cover the deficient area. It can be seen that:
• The time to onset of side-effects is determined by the
skin turnover time: 2 weeks for skin but 5 days for
small intestine
• The severity and length of time to recovery depend on
the amount of damage to the stem cells and hence on
radiation dose
• Provided there is a certain number of clonogenic cells
surviving, recovery is likely to be complete.
Although this mechanism is responsible for most acute
reactions, the clinical effect varies from site to site. For
example, in the upper gastrointestinal tract acute reac-
tions cause inflammation and discomfort with mucositis
and oesophagitis; small or large bowel damage by similar
mechanisms causes vomiting, diarrhoea or, more rarely,
ulceration and bleeding.
Other acute reactions, however, may operate by differ-
ent mechanisms and are less well understood, such as
somnolence after cranial irradiation.
Late irradiation effects
Although acute effects are important for the tolerance of
radiotherapy, the dose of radiotherapy applied is usually
limited by long-term, late radiation effects.
Stem cell effects
Stem cell damage usually recovers completely but, if it is
severe, long-lasting effects can occur. The most important
example of this is gonadal damage. Oocytes are particu-
larly radiosensitive and even moderate doses of a few
grays of radiation precipitate premature menopause.
Spermatogenesis is also sensitive to radiotherapy. Doses
in the region of 3 Gy cause oligospermia or azoospermia
that may last 6 months to 1 year, but higher doses, more
than 6 Gy, cause permanent sterility.
280
PRINCIPLES OF RADIOTHERAPY
28
Depletion of parenchymal or connective
tissues
In many tissues the parenchymal cells turn over very
slowly. As radiation damage is expressed at mitosis, lethal
damage will not be expressed until cells divide, weeks,
months or even years later. Irradiation of the thyroid
gland, for example, leads to gradual depletion of thyroid
follicular cells and can cause hypothyroidism over a
period of many years.
Vascular damage
Damage to the vasculature is a common mechanism of
damage, especially in tissues that never replicate, such as
neurons or cardiac muscle, or which replicate only very
slowly, such as fibroblasts. Radiation has a wide range of
pathological effects on the vasculature, due to damage to
both endothelial cells and connective tissue. This leads to
impairment of the fine vasculature, often in a patchy
fashion. The damage can result in poor wound healing,
tissue atrophy, ulceration, strictures and formation of
telangectasia.
The precise clinical effect depends on the organ
involved. For example, in the bladder the telangiectasia
can cause haematuria, while fibrosis, ulceration and
tissue atrophy can cause a constricted fibrotic bladder
resulting in frequency and nocturia. Similar changes in
the gastrointestinal tract may cause bowel obstruction by
stricturing of the viscus or by peritoneal adhesions.
At other sites vascular damage manifests differently. In
the central nervous system, glial tissues are depleted as a
direct effect of radiation and via vascular effects, causing
secondary demyelination and neuronal loss. Damage to
the cardiac vasculature may result in early ischaemic
heart disease if the dose is high enough, with myocardial
infarction being an increasingly recognized cause of late
morbidity and mortality in a minority of patients 15 years
after internal mammary irradiation for breast cancer.
Lymphatic damage
High-dose radiotherapy can also damage lymphatic
vessels, leading to reduced drainage and limb lymph-
oedema. The risk is increased if there has been previous
or successive surgery. For example, radiotherapy to the
axilla after complete axillary dissection for early-stage
breast cancer carries a much higher risk of arm lymph-
oedema than either modality alone.
Late effects are usually irrecoverable and show a dose
response. Low doses are less likely to cause damage,
while progressively higher doses have a greater chance of
causing complications and this damage becomes clini-
cally relevant at an earlier stage. The radiation dose there-
fore has to be chosen carefully, taking into account normal
tissue tolerance as well as predicted tumour cure dose
and, as long as this is done, organs will function normally
for the remainder of the patient's life. The actual dose
chosen depends on a variety of factors. For each site an
acceptable level of damage must first be decided and bal-
anced against the chance of tumour control (Fig. 28.4).
Damage to the spinal cord has such disastrous conse-
quences that no morbidity can be accepted. A lower dose
than that used at many other sites has to be accepted,
even at the expense of tumour cure probability. Damage
to other soft tissues, such as muscle and fat, is undesirable
but of lesser importance and a higher dose and higher risk
are accepted. As mentioned previously, the volume
treated is important: the larger the volume, the greater the
risk of damage and the lower the tolerable dose; for
example, for the spinal cord a short length of cord can be
treated to 50 Gy, but long segments, over 1 cm, will not
tolerate more than 40 Gy. Other factors affecting tolerance
include age, children and the elderly being less tolerant,
or pre-existing vascular disease and previous surgery
Second malignancy
In addition to specific organ complications the problem
of secondary malignancies is being increasingly recog-
nized. This has been best studied in Hodgkin's disease,
where an increased incidence of acute leukaemias are
seen 3-10 years after irradiation, with a smaller increased
risk of solid tumours following (Swerdlow et al 1992).
100-1
•A
O.
2
E
3
50-
Patients cured
Patients with
complications
Dose
Fig. 28.4 The relationship between cure and
complications. A dose may be chosen with a very low
risk of observable side-effects, but this may mean a very
low chance of tumour cure as well (A). On the other
hand, a high tumour cure rate may be associated with
an unacceptable rate of complications (C), forcing an
intermediate dose to be chosen as optimal under a
particular set of clinical circumstances (B).
281
28
MALIGNANT DISEASE
The precise risk is difficult to quantify, but data give an
overall risk of leukaemia of approximately 1-2% at
15 years. The risk is greatest if radiotherapy is given in
conjunction with, or is followed by, chemotherapy -
especially chemotherapy with alkylating agents such as
cyclophosphamide or chlormethine (mustine); in one
series it was 0.2% if no chemotherapy was used and 8.1%
if the patient received multiple courses. Similar increased
incidence of leukaemia has been seen in other cohorts of
patients, including those with ankylosing spondylitis
who have received spinal irradiation (Weiss et al 1994).
Of perhaps more concern is the risk of solid malignancy,
which is increasingly recognized, estimates rising to 10%
of patients surviving Hodgkin's disease 15-20 years
following radiotherapy, although a disease-related
phenomenon could also be responsible (Swerdlow et al
1992). This risk of secondary malignancy has to be
balanced against the risks of dying from the primary
disease in most cancer sufferers.
In conclusion, radiotherapy is set to remain the chief
curative modality in patients with non-surgical cancer. As
screening and other early detection methods diagnose an
increasing percentage of individuals with truly localized
disease, its importance is likely to increase. This con-
tinued role in the curative treatment of cancer patients
continues to stimulate research into the technical and
biological basis of radiotherapy. In future years, further
improvements in the efficacy and safety of radiotherapy
should be expected to result from this research.
Summary
• Do you recognize that treatment with
multiple beams of high energy X-rays given
daily over several weeks is the optimal
method? This is because of the physical
and biological attributes of radiotherapy.
• Can you identify circumstances when
radiotherapy offers an effective
alternative to surgery for local control of
many cancers?
• Do you understand what adjuvant
radiotherapy is and its frequent value in
improving local control?
• In advanced cancer do you appreciate the
value of short courses of palliative
radiotherapy?
• Will you remember the limitations on
radiation dose because of possible late
effects that may develop after months or
years?
References
Asbell SO, Krall JM, Pilepich MV et al 1988 Elective pelvic
irradiation in stage A-2, B carcinoma of the prostate: analysis
of RTOG 77-06. International Journal of Radiation Oncology
Biology Physics 15(6): 1307-1316
Bleehen NM, Girling DJ, Fayers PM, Aber VR, Stephens RJ 1991
Inoperable non-small-cell lung cancer (NSCLC): a Medical
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Brada M, Ross G 1995 Radiotherapy for primary and secondary
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Coindre JM, Terrier P, Nguyen-Binh B et al 1996 Prognostic
factors in adult patients with locally controlled soft tissue
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Oncology 14(3): 869-877
Dearnaley DP, Khoo VS, Norman A et al (1999) Comparison of
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radiotherapy in prostate cancer: a randomized trial. Lancet
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Dische S, Saunders M, Barrett A, Harvey A, Gibson D, Parmar
M 1997 A randomised multicentre trial of CHART versus
conventional radiotherapy in head and neck cancer.
Radiotherapy and Oncology 44(2): 123-136
Graf W, Dahlberg M, Osman MM, Holmberg L, Pahlman L 7
GHmelius B 1997 Short-term preoperative radiotherapy
results in down-staging of rectal cancer: a study of 1316
patients. Radiotherapy and Oncology 43(2): 133-137
Horiot JC, Le Fur R, N' Guy en T et al 1992 Hyperfractionation
versus conventional fractionation in oropharyngeal
carcinoma: final analysis of a randomized trial of the EORTC
cooperative group of radiotherapy. Radiotherapy and
Oncology 25(4): 231-241
Huddart RA, Rajan B, Law M, Meyer L, Dearnaley DP 1997
Spinal cord compression in prostate cancer: treatment
outcome and prognostic factors. Radiotherapy and Oncology
44(3): 229-236
Pollack A, Zagars GZ 1996 Radiotherapy for stage T3b
transitional cell carcinoma of the bladder. Seminars in
Urology and Oncology 14(2): 86-95
Price P, Hoskin PJ, Easton D, Austin D, Palmer SG, Yarnold JR
1986 Prospective randomised trial of single and multifraction
radiotherapy schedules in the treatment of painful bony
metastases. Radiotherapy and Oncology 6(4): 247-255
Priestman TJ, Dunn J, Brada M, Rampling R, Baker PG 1996
Final results of the Royal College of Radiologists' trial
comparing two different radiotherapy schedules in the
treatment of cerebral metastases. Clinical Oncology
8(5): 308-315
Quilty PM, Kirk D, Bolger JJ, Dearnaley DP et al 1994 A
comparison of the palliative effects of strontium-89 and
external beam radiotherapy in metastatic prostate cancer.
Radiotherapy and Oncology 31(1): 33-40
Swerdlow AJ, Douglas AJ, Vaughan Hudson G, Bennett MH,
MacLennan KA 1992 Risk of second primary cancers after
Hodgkin's disease by type of treatment: analysis of 2846
patients in the British National Lymphoma Investigation.
BMJ 304(6835): 1137-1143
Warde P, Payne D 1992 Does thoracic irradiation improve
survival and local control in limited-stage small cell
carcinoma of the lung? A meta-analysis. Journal of Clinical
Oncology 10(6): 890-895
282
PRINCIPLES OF RADIOTHERAPY
28
Weiss HA, Darby SC, Doll R 1994 Cancer mortality following
x-ray treatment for ankylosing spondylitis. International
Journal of Cancer 59(3): 327-338
Work E, Bentzen SM, Nielsen OS et al 1996 Prophylactic cranial
irradiation in limited stage small cell lung cancer: survival
benefit in patients with favourable characteristics. European
Journal of Cancer 32A(5): 772-778
Wurm R, Warrington AP, Laing RW et al 1994 Stereotactic
radiotherapy for solitary brain metastases as alternative to
surgery (Meeting abstract 050). British Journal of Cancer
70(suppl22):21
Further reading
Dobbs J, Barrett A 1985 Practical radiotherapy planning.
Edward Arnold, London
Horwich A 1995 Oncology: a multidisciplinary textbook.
Chapman & Hall, London
Steel GG 1993 Basic clinical radiobiology for radiation
oncologists. Edward Arnold, London
283
Cancer chemotherapy
V. M. Macau lay, C Coulter
m
Objectives
Understand the actions of cytotoxic drugs,
endocrine therapy and the new biologicals.
Recognize the indications for, and timing
and administration of, chemotherapy by
multidisciplinary teams.
Understand objective clinical response, and
adjuvant, neoadjuvant and palliative
chemotherapy.
Appreciate the importance and design of
new drug trials.
INTRppyCTION
Localized tumours can be cured by surgery and /or radio-
therapy. Primary tumours are rarely the cause of death
unless they are in critical sites such as the brain. Most cancer
deaths are attributable to direct or indirect effects of
metastatic disease, and this requires systemic treatment.
There are three main types of systemic anticancer therapy:
chemotherapy, endocrine therapy and biological therapy.
Paul Ehrlich was the first to use the term 'chemother-
apy', in the early 1900s. Chemotherapy was initially shown
to be effective in the 1940s and 1950s when nitrogen
mustard, aminopterin and actinomycin were used to treat
lymphoma, leukaemia and Wilms' tumour. Subsequent
work has confirmed that cytotoxic drugs can indeed cure
disseminated disease in a significant proportion of patients
with germ cell tumours, lymphomas, leukaemias and a
few with small cell lung cancer and ovarian cancer.
Unfortunately, most metastatic common solid tumours
remain incurable, although cytotoxic and endocrine ther-
apies undoubtedly have useful anticancer activity that can
effectively palliate symptoms. The last 10-20 years have
seen many advances in our knowledge of the cellular and
molecular processes that characterize cancer cells. The
challenge now for oncologists is to translate these advances
into new therapeutic approaches that will improve the
outlook for patients with common cancers.
BASIC PRINCIPLES
Growth characteristics of tumours
1 . Cancers are caused by mutations in genes that influ-
ence critical aspects of normal growth regulation (see
Ch. 26). A common early event is the loss of ability to
replicate (copy) faithfully deoxyribonucleic acid (DNA).
This so-called genomic instability (genome = the full
set of genes) leads in turn to mutations in other genes,
including those that regulate growth and survival, drug
resistance, cell-cell interactions, invasion, angiogenesis
(formation of new blood vessels) and the ability to evade
immune recognition. These changes give the cell a growth
advantage, leading to tumour formation.
2. Within an individual tumour only a subset of cells is
proliferating — the growth fraction 7 . In general, small
tumours have high growth fractions, but as the tumour
enlarges the growth fraction often falls. Chemotherapy
tends to be less effective in larger tumours because the
growth fraction is smaller, and there has been a longer
time for mutation to occur in genes that determine drug
resistance. In addition, central regions of large tumours
are often poorly perfused, reducing drug access, and the
hypoxic cells are usually chemoresistant. This is why
early diagnosis is so important.
3. The smallest tumours currently detectable are well
advanced in their natural history: a tumour of -1 cm 3
weighs "1 g, contains 10 9 cells, and has gone through
30 doublings. In only 10 more doublings it will reach 10 12
cells, representing -1 kg of tumour, which is usually
lethal. This problem of the threshold of detectability
applies not only in the diagnosis of a primary tumour, but
also in patient management after apparently curative
resection of a localized cancer. Many such patients
harbour tiny tumour deposits, so-called micrometastases.
These can be found by examining bone marrow using
specialized immunostaining or molecular techniques, but
cannot be detected by currently available clinical scans.
Little is understood about how tumour cells can remain
viable but quiescent, presumably in the G phase of the
cell cycle, and how or why they can reinitiate growth after
latent periods of months or years.
284
CANCER CHEMOTHERAPY
29
Principles of cytotoxic chemotherapy
Cytotoxic drugs damage DNA, inhibit DNA
synthesis or block cell division
Many standard cytotoxic (Greek kytos - vessel, hollow,
cell + toxon = bow, toxikos = for the bow, toxikon = arrow
poison) drugs kill rapidly-growing cells by damaging
their DNA. DNA double-strand breaks are highly toxic,
and if not repaired will lead to cell death. Other drugs act
by interfering with DNA synthesis or cell division
(Fig. 29.1). Cytotoxic drugs show no intrinsic specificity
for cancer cells versus normal tissues: in addition to
killing tumour cells, they damage normal tissues that are
rapidly dividing, including the normal bone marrow, gut
lining and hair follicles. An element of selectivity can be
introduced by careful adjustment of dose and schedule to
maximize damage to the tumour while allowing recovery
of normal tissues (Fig. 29.2).
Pyrimidine
synthesis
Cyclophosphamide
Alkylaling agent, links R*CH 2 + to DNA
forming inter- and inlra- strand cross- links
Purine
synthesis
Ribonucleotides
nm
mmmmmm
Cisplatin
Inter- and intra- strand crass-links
Bleomycin
DNA strand breaks
mvRTTPfpmfHPmii
Doxorubicin
Etoposide
Inhibit Topoisomerase II causing
DNA strand breaks
xyribonucleotides
i
:..:::::::::::;::::;:: ::...::
Irinotecan
Inhibits To poj some rase I
DRUGS CAUSING DNA DAMAGE
DNA
_T
RNA
I
Protein
Methotrexate
Inhibits di hydrate I ate reductase (DHFR)
Hydroxyurea
nhibits ribonucleotide reductase
hmmmmmmmmmmmmimmmimimmm
I 5 Flourouracil
\ Inhibits thy mid y late synthetase.
: blocks DNA synthesis
Cytosine arabinostde
j Cytosine analogue terminates DNA synthesis
Inhibits DNA polymerase
Actinomycin D
Blocks RNA synthesis
DRUGS BLOCKING SYNTHESIS
OF DNA OR RNA
Vinca alkaloids
Btock micratubular assembly
so block cells in M phase (mitosis)
Taxanes
Block disassembly of microtubules in
mitotic spindle so block cells in M phase
1
DRUGS CAUSING SPINDLE DAMAGE
Fig. 29.1 Actions of cytotoxic drugs at the molecular level. Pathways involved in DNA synthesis and gene expression,
the process whereby information encoded in DNA is transcribed (copied into RNA) and translated into protein.
Cytotoxic drugs in the box on the left-hand side act primarily by causing DNA damage. This may be a direct effect
(e.g. due to bleomycin) or may occur indirectly, e.g. via inhibition of topoisomerases, enzymes that bind to DNA and
induce and reseal strand breaks. These breaks are important for relieving torsional stress as the DNA double helix
unwinds prior to DNA synthesis. Drugs in the box on the right-hand side block specific steps in DNA or RNA synthesis,
and drugs in the lower box interfere with the function of tubulin, the protein in the mitotic spindle. Modified with
permission from Grahame-Smith DG, Aronson JK 2002 Oxford textbook of clinical pharmacology and drug therapy,
3rd edn. Oxford University Press, Oxford.
285
29 "
MALIGNANT DISEASE
^^^^^^^UHUhi
Classification of cytotoxic drugs
The mechanism of cell kill dictates when cytotoxic drugs
are effective, and how cell kill varies with increasing dose
(Table 29.1 and Figs 29.2 and 29.3):
• Non-phase-dependent drugs:
Are equally toxic to cycling cells and those that are non-
cycling (i.e. G )
Kill by damaging DNA directly
Kill exponentially with increasing dose.
• Phase-dependent drugs:
Kill cells only in a specific part of the cell cycle, usually
S (DNA synthesis) or M (mitosis)
Linear cell kill up to a plateau, limited by proportion of
cells in target phase.
Some drugs have multiple mechanisms of action. For
example doxorubicin intercalates between the DNA
strands, generating free radicals, and also inhibits
the enzyme topoisomerase II (see Fig. 29.1). It is toxic
ID
12
10
11
IHH
Chemotherapy
treatments
| 10 10 -
in
rt 1 er-
as
o TQ B 1
$
E 10 7 -
z
10 6 H
10 5 -
Bone
marrow
Tumour
Time
Fig. 29.2 Effect of chemotherapy cycles on tumour
growth and blood count. The effect of repeated cycles
of chemotherapy (arrows) on tumour growth (solid line)
and marrow progenitor cells (hatched line). The interval
between treatments is designed to allow normal tissue
recovery without tumour regrowth; however, with
repeated doses there is less killing of tumour cells,
indicating the emergence of drug resistance. At some
point all the sensitive tumour cells will have been killed
and only the resistant cells remain. The marrow recovers
quickly after initial treatments, but with repeated doses
recovery is less complete and myelosuppression becomes
clinically evident. Modified with permission from
Souhami and Tobias (2002).
Vinca alkaloids
Taxanes
Methotrexate
Cytosine arabinoside
Cam plot hecms
Doxorubicin
Etoposide
J
Fig. 29.3 Actions of cytotoxic drugs within the cell
cycle. M, mitosis; S, DNA synthesis; G 1f first gap phase;
G 2 , second gap phase; G , quiescent non-cycling cells.
during all phases of the cell cycle but particularly in S
phase.
'Fractional cell killing'
In 1964, Skipper showed that survival is inversely related
to tumour burden and that for most drugs there is a clear
relationship between drug dose and the eradication of
tumour cells. A given dose of a drug kills a constant pro-
portion of cells, not a constant number. The implication of
this concept of "fractional cell killing' is that tumour eradi-
cation requires either a sufficiently high dose of the
drug(s) within limits tolerated by the host, or that treat-
ment is started when the number of cells is small enough
to allow tumour destruction at reasonably tolerated doses.
Standard chemotherapy uses doses that often cause
mild/ moderate side-effects, most of which can be
controlled by simple symptomatic treatments such as
antiemetics (see below). In contrast, high dose chemother-
apy, used for example in the treatment of leukaemias and
lymphomas, causes severe and sometimes life-threatening
toxicity, including profound myelotoxicity (Greek myelos
= marrow; bone marrow).
286
Tabte 29.1 Cytotoxic drugs
Class of agent
Mode of action
Examples
Uses (examples)
Main toxicities
Alkylating agents
Link alkyl group (R-CH-) to
chemicat groups in proteins
Cyclophosphamide
Breast, SCLC, NHL,
Hodgkin's, sarcomas
Marrow, cystitis
and nucleic acids
Cisplatin
Ovary, teratoma,
seminoma, bladder, lung,
head and neck
Neuropathy, renal (irreversible),
deafness (irreversible)
Carboplatin
Ovary
Marrow
Gemcitabine
Pancreatic, NSCLC
Flu-Jike symptoms, skin rash
Dacarbazine {OTIC)
Melanoma
Marrow, flu-like symptoms, arm pain
Chlorambucil
Low grade NHL
Marrow, leukaemia
Antimetabolites
Resemble DNA precursors,
Methotrexate
Breast, sarcomas, NHL
Mucositis (eyes, mouth), renal, fiver
block DNA synthesis or
5-Fluorouracil (5FU)
Colorectal, breast
Gut toxicity, hand-foot syndrome
replication
Capecitabine
Colorectal
AsSFU
Antitumour antibiotics
Bind to DNA, intercalate
between base pairs.
Doxorubicin,
Breast, lymphomas, SCLC,
ovary, bladder
Marrow, cardiotoxic
Inhibit topoisomerase II
Epirubicin
Breast
Marrow, mild cardiotoxtctty
Mitoxantrone
NHL, breast
Mild cardiotoxicity
Single-and double-strand
Bleomycin
Teratoma, seminoma, head
Pulmonary toxicity
DNA breaks
and neck, lymphomas
Vmca alkaloids
Bind to tubulin, prevent
Vincristine
NHL, SCLC
Neuropathy, constipation
assembly of mitotic spindle
Vinblastine
Testicular, NHL
Marrow, mucositis
Vindesine
Melanoma
Neuropathy
Vinorelbine
NSCLC, breast, ovary
Neuropathy, constipation
Taxanes
Bind to tubulin, stop
Paclitaxel (Taxol)
Ovary, breast
Neuropathy, rash
disassembly of mitotic
Docetaxel (Taxotere)
Breast, ovary
Neuropathy, rash
spindle
Epipodophylotoxins
Inhibit topoisomerase II
Etoposide
Lung, testicular
Bone marrow
Camptothedns
Inhibit topoisomerase I
Irrnotecan
Colorectal
Gut, bone marrow
Topotecan
Lung, ovary
Marrow
NHL r non-Hodgkin's lym
phoma; NSCLC, non-small cell lung cancer; SCLC, small ce
>ll lung cancer.
>
m
n
X
m
O
H
30
>
I
00
ID
29 '"
MALIGNANT DISEASE
Mechanisms of drug resistance
Resistance to specific drugs can be conferred by:
• Drug efflux, i.e. the cancer cell is able to pump the
drug out. The product of the multidrug resistance
(MDR) gene, a transmembrane protein (P-glycoprotein),
acts as a drug efflux pump. Unfortunately clinical
trials of efflux pump inhibitors have so far been dis-
appointing,
• Increased synthesis within the cell of:
Cytoplasmic enzymes that detoxify the drug, e.g. over-
expression of certain glutathione-S-transferases confers
resistance to cyclophosphamide
The drug target, e.g. amplification (increased copy
number) of the dihydrofolate reductase (DHFR)
gene confers resistance to methotrexate.
• Reduced expression of:
Enzymes that activate the drug, e.g. enzymes that
convert 5-fluorouracil (5FU) to its active metabolite
Proteins targeted by the cytotoxic drug, e.g. reduction
in levels of the enzyme topoisomerase II confers
resistance to topoisomerase II inhibitors e.g. anthra-
cyclines, etoposide.
In addition, cancer cells may become generally resist-
ant to killing via mutation or altered expression of
proteins that regulate cell survival and susceptibility to
apoptosis (Greek apo = from + ptosis = a falling), such
as Bcl-2, p53.
Likelihood of cell killing
This depends on:
• Whether the cell is intrinsically sensitive or resistant to
the action of the drug.
• The cycling of the tumour cell (for phase-specific
agents).
• The concentration of drug delivered to the tumour.
This is a function of dose and schedule. There is evi-
dence of a dose-response relationship for some cyto-
toxic drugs, and in breast cancer doxorubicin has been
shown to confer greater therapeutic benefit at high
dose. Very high dose chemotherapy, with autologous
bone marrow or stem cell support, is a technique used
for treatment in acute leukaemia or as second-line
therapy in lymphomas. So far no benefit has been
shown for trials of this approach as treatment for
women with high risk early breast cancer or metastatic
breast cancer.
Combination chemotherapy
To maximize the chance that a tumour will respond to
therapy, cytotoxic drugs are often used in combination.
The principles of combination chemotherapy are that the
selected drugs should:
• Be active against the tumour when used alone
• Have different mechanisms of action, to maximize
tumour cell kill
• Have a different spectrum of side-effects, to minimize
toxicity to the patient.
Timing of chemotherapy
• Primary therapy for chemosensitive tumours such as
lymphomas, leukaemias and teratomas. Here chemo-
therapy is the main treatment modality and can achieve
cures.
• Palliative chemotherapy (Latin palliate = to cloak; hence
mitigate, extenuate). Most common cancers are less
chemosensitive, and patients with metastatic disease
cannot hope to be cured, but they may obtain useful
symptomatic benefit. It is important to monitor tumour
response and stop or change treatment if there is no
evidence of objective response (see point 11 below).
• Adjuvant chemotherapy (Latin ad = to + juvare = to
help). Many patients with early cancer can be cured by
surgery. Certain features suggest a high risk of recur-
rence; these vary with tumour type but often include
size of the primary, grade (i.e. degree of differentiation),
involvement of local lymph nodes, and vascular inva-
sion. Current imaging techniques are unable to detect
tumour deposits smaller than 2-3 mm, so it is imposs-
ible to know with certainty which patients have been
cured by surgery and which have micrometa static
disease that will later cause overt recurrence and
death. In cancers of the breast and colon, patients at
high risk of recurrence should be offered adjuvant
chemotherapy and /or endocrine therapy, in an attempt
to kill residual tumour cells remaining after apparently
complete local resection. There is no way to judge the
efficacy of this approach in individual patients other
than to await relapse. Therefore, in designing adjuvant
therapy, use only those agents shown to be active in
advanced disease.
• Neoadjuvant chemotherapy describes the use of
cytotoxic drugs as initial (presurgery) treatment for
patients who present with localized but extensive
cancer, such as large primary breast cancers. The aim
is to shrink the primary tumour to permit a more con-
servative operation, and to control micrometastatic
disease. The effect can be monitored by serial measure-
ment of the size of the primary tumour. In patients
with breast cancer this is most accurately done by serial
magnetic resonance imaging (MRI) scans, or failing
that by ultrasound; clinical measurements are notori-
ously inaccurate.
288
CANCER CHEMOTHERAPY
29
Manage cancer patients within
multidisciplinary teams
• Work closely with pathologists, clinical oncologists
(radiotherapists), medical oncologists, clinical nurse
specialists, radiologists and palliative care physicians.
• Unit policies for cancer treatment should be based on
the results of published studies including randomized
trials.
• Make management decisions after joint consultation
with other members of the team.
• Offer patients treatment options appropriate for their
age, health, tumour type and stage.
Practicalities of administration
• It is essential that cytotoxic drugs be given by a trained
doctor or nurse.
• Most standard chemotherapy regimens are given on an
outpatient basis every 3-4 weeks.
• The dose is usually calculated on the basis of milli-
grams per square metre of body surface area.
• Dose and schedule may need to be adjusted according
to the function of:
Liver, principal site for metabolism/excretion of doxo-
rubicin, mitozantrone and vinca alkaloids. If the
serum bilirubin is elevated use these agents with
caution, at reduced dose.
Kidneys: drugs that are cleared by the kidney may cause
increased toxicity if the patient has impaired renal
function. Check the renal function before each course
of chemotherapy when giving certain drugs, espe-
cially cisplatin, cyclophosphamide, ifosfamide and
procarbazine, and any high dose chemotherapy.
Ensure that the patient is well hydrated before,
during and after drug administration. Carboplatin
has similar activity to cisplatin and may be given to
patients with renal impairment, tailoring the dose to
creatinine clearance.
Key points
A given dose of chemotherapy kills a constant
proportion of cells, not a constant number of
cells.
Cytotoxic drugs are used in combination to
maximize tumour cell kill.
Cancer patients should be managed by
multidisciplinary teams.
It is essential that cytotoxic drugs are given by
a trained doctor or nurse.
• Tumour responses are defined by objective
criteria.
• Chemotherapy works better in fit patients.
Routes of administration
• Intravenous injection/ infusion: the commonest route
for cytotoxic drugs, usually via a temporary venous
cannula (drip). Long term venous access devices may
be required for convenience, because of poor veins or
for infusional chemotherapy. Long term catheters are
inserted so that the tip lies in a large central vein.
Various catheters are available, including those suit-
able for insertion into the subclavian or internal
jugular veins, such as Hickman or Groshong, and
others for insertion into a peripheral (e.g. antecubital)
vein.
• Oral administration, e.g. cyclophosphamide, methotrex-
ate, etoposide, capecitabine.
• Subcutaneous administration: commonly used for
interferon or interleukin-2 administration.
• Intra-arterial: an implanted pump may be placed into
the common hepatic artery to infuse chemotherapy
continuously into the liver. This technique is being
evaluated in patients with liver metastases from the
colon and rectum.
• Intrathecal chemotherapy with methotrexate or cytosine
arabinoside is used for brain /meningeal involvement
by leukaemias, lymphomas, teratomas, choriocarcino-
mas and occasionally for central nervous system (CNS)
involvement by common solid tumours such as breast
cancer. As with all chemotherapy, this should be
administered only by trained personnel, to avoid the
catastrophic and invariably fatal consequences of
intrathecal administration of vincristine.
Clinical assessment of response
So that oncologists around the world can compare the
efficacy of different agents, it is important to define what
is meant by a response. One or more tumour deposits
(marker lesions) are selected for measurement in two
dimensions, on plain X-ray, ultrasound, computed
tomography (CT) or MRI scan. This enables calculation of
the cross-sectional area (product of the two dimensions)
of each deposit. These measurements are made immedi-
ately before the start of treatment and again during /after
treatment, and responses are defined as shown below. It
is worth remembering that tumour shrinkage need last
for only 4 weeks to count as a response. These are the
World Health Organization criteria:
• Complete response (CR): no evidence of disease
remains after treatment
289
29 "
MALIGNANT DISEASE
• Partial response (PR): marker lesion(s) shrink by 50%,
no new lesions have appeared
• Stable disease (SD): marker lesions remain at 50% to
125% of pretreatment size (to allow for observer error
in measurement)
• Progressive disease (PD): marker lesions have
increased to >125% of pretreatment size or appearance
of new lesions
• Response rate: CR plus PR.
There has recently been a move to replace these criteria,
emphasizing the role of CT and MRI imaging of marker
lesions and formalizing the monitoring and analysis of
response. Time will tell whether these new 'RECIST'
criteria (response evaluation criteria in solid tumours)
will replace the WHO criteria listed above.
Fit patients do better with chemotherapy
In general, chemotherapy has greater benefit in patients
who have 'good performance status', that is, they are fit
and able to walk about. In patients with 'poor perfor-
mance status', that is, confined by their illness or by con-
comitant disease to a bed or chair for most of the day,
chemotherapy often has more severe side-effects and less
benefit than in fit patients. This should not deter you from
offering chemotherapy to a patient with a potentially
curable tumour. However, in a patient with a cancer that
can only be palliated by chemotherapy, it may be better
to face the reality that such treatment may do more harm
than good. In either case, make full use of simple
measures such as analgesics and laxatives, which palliate
symptoms without severe toxicity.
TOXICITY OF CHEMOTHERAPY
^£^^*^^X&^^^
?^^^^^gSSSii^
The dose of an anticancer drug is limited by its toxic
effects on normal tissues. Some of these effects are mani-
fest acutely, within minutes to weeks of administration,
and may necessitate adjustment of dose or schedule.
Some effects may be delayed for months or years, in some
cases long after completion of the therapy that caused
them, that is, when it is too late for dose modification or
cessation of treatment.
>~
Neutropenic sepsis:
• Can cause collapse and death within a few
hours.
• Can occur any time after chemotherapy.
• Greatest risk 7-14 days after most drugs.
• Always check blood count if the patient is
unwell.
• Requires urgent admission and intravenous
antibiotics.
Acute toxicity
Extravasation
Doxorubicin and vinca alkaloids are vesicant (Latin vesica
= blister) drugs; they cause tissue destruction when
extra vasated. This leads to severe pain, burning and scar-
ring and can be avoided by ensuring that the needle is
within the vein and that the vein is tested using a non-
vesicant substance before starting injection of the vesicant
drugs. If extravasation does occur, stop drug administra-
tion immediately. Tissue damage can be limited by
promptly administering corticosteroids by local injection
or topical application.
Key point
Every chemotherapy unit should display clear
protocols outlining action to be taken in the
event of extravasation.
Bone marrow toxicity
For many cytotoxic drugs, bone marrow toxicity is dose
limiting. It is mandatory that a full blood count is taken
on the day of the treatment; most treatments can go
ahead with a white blood count of >1 .5—2 x 10 9 1~\ and
platelets of >100 x 10 9 l 1 , although this varies with
different protocols. Delay or modify treatment, that is
reduce the dose, if the blood count is inadequate. The
risk of myelosuppression is greatest approximately
10-14 days after cycles of most sorts of chemotherapy.
Warn patients to alert the oncology department if they
have a fever above 37.5 D C. Act promptly, because
patients can die from neutropenic sepsis within a few
hours. Manage fever in a patient with an absolute neu-
trophil count of less than 1.0 x 10 9 by urgent admission
and treatment with intravenous broad -spectrum anti-
biotics. Include in the investigations cultures of blood,
urine and from any indwelling line. It is unusual to
isolate a pathogen, although patients with indwelling
lines are at particular risk of staphylococcal infection,
which may necessitate line removal if it cannot be erad-
icated with antibiotics. Spontaneous bleeding does not
usually occur until the platelet count falls to 20 x 10 9 , but
check patients with low counts for signs of haemorrhage.
Give platelet support if bleeding occurs - typically on
290
CANCER CHEMOTHERAPY
29
the shins but you should check all over, including the
mouth and ocular fundi, and prophylactically if the
count falls below 10-20 x 10 9 per litre.
Key points
• Chemotherapeutic agents are dangerous. They
must be administered only by skilled, trained
people.
• Monitor the white cell count assiduously and
respond to falls by delaying or modifying
treatment.
• Keep neutropenic sepsis in mind - always.
Gastrointestinal toxicity
Nausea and vomiting are caused by many drugs and can
be severe with cisplatin, cyclophosphamide, doxorubicin
and actinomycin C This is probably the result of a
combination of stimuli from the chemoreceptor trigger
zone, the gut and the cerebral cortex. Patients receiving
mildly emetic chemotherapy, such as cyclophosphamide,
methotrexate, fluorouracil (CMF) for breast cancer,
respond to metoclopramide or domperidone and dexa-
methasone. For patients receiving highly emetogenic
drugs such as cisplatin, give a 5-hydroxytryptamine
antagonist such as ondansetron or tropisetron prophyl-
actically, together with dexamethasone. Oral premedi-
cation with lorazepam may help the patient to relax
before treatment. Uncontrolled vomiting is not only
extremely unpleasant, but also dangerous, as dehydra-
tion can increase toxicity, for example, the nephrotoxic-
ity of cisplatin. You may need to admit a patient for
intravenous rehydration if vomiting cannot be controlled
by oral medication. Standard dose methotrexate can
cause mucositis, manifest as soreness of the mouth and
eyes. If this is severe, give calcium leucovorin (folinic
acid) for 48 h, starting 24 h after subsequent courses of
chemotherapy. Folinic acid is an alternative intermediary
metabolite that bypasses the block in DHFR activity, ter-
minating the cytotoxic effect of methotrexate (note that
folinic acid enhances the activity of 5-fluorouracil). High
dose methotrexate requires prophylactic folinic acid, at
doses that depend on the results of methorexate drug
level monitoring. Vincristine may cause constipation
and paralytic ileus, which may respond to laxatives.
5-Fluorouracil and its oral analogue capecitabine can
cause severe gut toxicity. Loperamide can be used pro-
phylactically or for mild diarrhoea, but stop treatment of
patients with severe diarrhoea - that is, 4-6 times a day
or at night, or bloody.
Alopecia (Greek alopex = fox; fox-like, patchy
baldness)
This results from treatment with doxorubicin, cyclophos-
phamide, etoposide, vincristine, paclitaxel and docetaxel.
Hair loss usually starts 18-21 days after the first injection
of these drugs, but is temporary and patients can be reas-
sured that the hair will regrow after treatment has been
completed. Wigs are available on the National Health
Service (NHS) and should be provided for patients before
hair loss occurs. Alopecia due to doxorubicin and doce-
taxel may be avoided or reduced by scalp cooling, which
limits blood flow and hence drug access to the scalp. This
carries a theoretical risk of scalp recurrence, but in
practice this is very rare.
Neuropathy
Irreversible peripheral neuropathy and ototoxicity can be
a serious problem with cisplatin. Vinca alkaloids and
taxanes inhibit, respectively, the assembly and disassem-
bly of microtubules; as well as blocking mitosis, this also
interferes with nerve conduction. Peripheral neuropathy
causes paraesthesia and numbness, which improve on
stopping taxanes but can be severe and irreversible with
pain and muscle weakness with the vinca alkaloids.
Vincas also cause autonomic neuropathy, manifest as
paralytic ileus and constipation.
Long-term toxicity
Cardiotoxicity
This is the most important chronic and dose-limiting side-
effect of doxorubicin, and causes arrythmias and cardiac
failure. The risk of cardiotoxicity is dose-related (so total
dose should not exceed 450 mg m~ 2 ) and is increased in
patients with pre-existing heart disease, previous treat-
ment with trastuzumab (Herceptin), or radiotherapy to
the mediastinum or left chest, for example postmastec-
tomy. The risk of cardiotoxicity appears to be less with the
related drugs mitoxantrone and epirubicin. Herceptin
itself causes cardiac dysfunction in approximately 5% of
patients and should not be administered in combination
with anthracyclines.
Pulmonary toxicity
Bleomycin can cause acute pulmonary infiltrates that may
disappear when the drug is stopped, but which often heal
leaving chronic fibrosis. This is a dose-related effect, com-
monly occurring at total doses over 300 000 units, but it can
occur after lower doses in patients with renal impairment.
Remember to alert the anaesthetist if a patient previously
treated with bleomycin is being prepared for operation.
291
29
MALIGNANT DISEASE
An example is a young man with a teratoma undergoing
excision of a residual tumour mass; high concentrations
of oxygen can acutely damage lungs exposed to
bleomycin. Mitomycin C can also cause pulmonary infil-
trates and fibrosis, and busulphan and other alkylating
agents can cause fibrosis.
form of systemic treatment offered to patients with
cancer, when in 1896 Beatson performed oophorectomy
for metastatic breast cancer. Surgical approaches have
now been almost completely replaced by medical treat-
ments designed to manipulate the levels or activity of key
hormones (Fig. 29.4).
Carcinogenesis
After long-term treatment with alkylating agents such as
chlorambucil and melphalan, patients are at risk of devel-
oping acute leukaemia. Leukaemia with specific chromo-
somal characteristics can develop after treatment with
etoposide. The risk is directly related to the total dose of
the drugs given. This is an important reason for reducing
the length of treatment and, therefore, the cumulative
dose of these agents. There is negligible risk of develop-
ing a second solid tumour after chemotherapy alone,
although the risk increases if chemotherapy is combined
with local irradiation.
Gonadal damage
This can follow treatment with alkylating agents, espe-
cially when used in combination. Ensure that patients
receiving chemotherapy receive counselling about the
risk of long-term infertility and the inadvisability of preg-
nancy during chemotherapy. After combination chemo-
therapy (e.g. MOPP; mustine, Oncovin, procarbazine,
prednisolone) for Hodgkin's disease, the majority of men
are azoospermia although the risk of this effect is reduced
by using alternative regimens such as ABVD (adriamycin,
bleomycin, vinblastine, dacarbazine). Offer all male
patients sperm banking before starting chemotherapy.
With modern assisted reproductive techniques it is
possible to achieve ovum fertilization with a very low
sperm count. Men do not need hormone replacement
therapy. For women aged over 30 years there is a very
high risk of permanent amenorrhoea when they have
received combination chemotherapy for Hodgkin's
disease. It is now possible,, but time-consuming and
expensive, to hyperstimulate the ovaries before
chemotherapy to obtain ova which can be fertilized and
frozen. Female patients will need hormone replacement
therapy. Men who receive treatment with cisplatin for
germ cell tumours usually retain fertility, as do women
who have received chemotherapy for choriocarcinoma.
Breast cancer
Breast cancer cell growth is stimulated by oestrogens, and
hormone responsiveness is likely if the tumour cells
express the nuclear hormone receptors oestrogen receptor
(ER, for US spelling, estrogen) and progesterone receptor
(PgR). Approximately one-third of all breast cancer
patients respond to hormonal measures; response rates
are -70% in patients with ER+, PgR+ tumours, and
30-40% in tumours positive for ER or PgR. Active agents
include:
• Tamoxifen (Nolvadex): a drug that acts as an antioestro-
gen in tumour cells, blocking activation of the ER by
endogenous oestrogens. In the rest of the body, tamox-
ifen acts as an oestrogen, protecting against osteopor-
osis and cardiovascular disease but also causing a
slightly increased incidence of endometrial cancer.
Tamoxifen is used both in the adjuvant setting and in
metastatic disease, and trials indicate that it can signi-
ficantly reduce the incidence of breast cancer in women
whose family history puts them at high risk of the
disease.^ In recent years, pure antioestrogens have
become available, and these are currently being
assessed in advanced disease.
• Anastrozole (Arimidex): an aromatase inhibitor that
blocks the conversion of androgens to oestrogens.
Aromatase inhibitors are effective in postmenopausal
patients but not in premenopausal women where the
intact hypothalamic-pituitary-gonadal axis is able to
overcome the drug-induced enzyme block.
• Goserelin (Zoladex): a leutinising hormone releasing
hormone (LHRH) analogue that prevents pituitary LH
release, leading to a fall in gonadal steroid production
in premenopausal women.
• Megestrol acetate (Megace) and medroxyprogesterone
acetate (Provera): synthetic progestins that antagonize
the cellular effects of oestrogens. These drugs are less
active than the above and they are usually used as
third-line therapy, for example after tamoxifen and an
aromatase inhibitor.
HORMONE THERAPY
Hormone therapies (= endocrine therapies) are used in
the management of patients with cancers of the breast,
prostate and endometrium. Historically this was the first
Prostate cancer
Prostate cancer cell growth is stimulated by androgens,
and treatment here aims to reduce circulating levels or to
block androgen effects at the cellular level. Since Huggins
292
CANCER CHEMOTHERAPY
29
r^.^.-r^^.y,..-^.,,,,,,,:..,,^.;,,
LHRH ANALOGUES
Hypothalamus
Gonad
J=>LHRHi=>
Pituitary s* — ^
Adrenal
l.
ADRENAUGONADAL
STEROID SYNTHESIS
Cholesterol
Pregnenolone
Progesterone
DHT ty
17a- Progesterone
^>
Testosterone < $- - !> Androstenedione
: Oestradiol ( E 2 ) <■ ={> Oestrone
Fig. 29.4 Endocrine pathways, sites of action of main hormonal agents. The main pathways involved in synthesis of
adrenal and gonadal hormones (shaded box) are shown. Dihydrotestosterone (DHT) binds to and activates the
androgen receptor (AR), which drives expression of androgen-responsive genes. Similarly, the expression of estradiol-
responsive genes is activated by binding of oestradiol (E 2 ) to the oestrogen receptor (ER). Hormonal anticancer agents
act either by blocking hormone production, e.g. aromatase inhibitors (note that luteinizing hormone releasing
hormone (LHRH) analogues first stimulate then suppress luteinizing hormone (LH) release, leading to a fall in
production of testosterone from the testis or oestrogen from the ovary). Other agents block the effect of the steroid
hormone at the molecular level, e.g. antiandrogens, antioestrogens. ACTH, adrenocorticotrophin.
discovered, in 1941, that metastatic prostate cancer is
almost always androgen-dependent, orchidectomy and
oestrogen therapy have been standard treatments.
Nowadays hormonal control can be achieved with fewer
side-effects using LHRH analogues such as goserelin,
and antiandrogens such as flutamide (Drogenil) and
bicalutamide (Casodex), which block the binding of
dihydrotestosterone to the androgen receptor.
Endometrial cancer
Progestogens such as medroxyprogesterone acetate are
useful in the treatment of patients with locally recurrent
or metastatic endometrial cancer. Approximately one-
third of patients respond, and responders live longer than
non-responders.
BIOLOGICAL THERAPY
Biological therapy produces antitumour effects through
the action of natural substances, or the use of agents that
block key biological processes in tumour cells.
Cytokines
Recombinant cytokines are agents that have roles in
normal physiology, and can now be made by recombinant
technology. This means that the cytokine gene is put into
bacteria or yeast, expression of the gene is induced, that
is the gene is 'switched on', leading to production of
messenger ribonucleic acid (RNA) and hence protein, and
the protein is purified from the culture in sufficient
quantities to be used as therapy.
293
29 *
MALIGNANT DISEASE
Interleukin 2 (IL-2) is a T-cell growth factor that is central
to T-cell-mediated immune responses. IL-2 has been
approved for treatment of metastatic renal cell carci-
noma. Response rates of 20% have been observed, and
50% of responding patients remain progression free 4-7
years following therapy. IL-2 also has activity against
malignant melanoma, but again the response rate is
only -20%.
Colony stimulating factors (CSFs) such as erythropoietin and
granulocyte CSF (filograstin) stimulate haematopoiesis
and immune functions. They do not have antitumour
effects but reduce chemotherapy-induced haematologi-
cal toxicity and are useful in the context of high dose
chemotherapy and bone marrow transplantation.
a-Interferon (IFNa). Interferons are made by the body in
response to viral infection. It is they rather than the
virus per se, that are responsible for the malaise and
myalgia characteristic of influenza. IFNa has demon-
strated activity against many solid and haematogenous
malignancies. A response rate of 80-90% has been
observed among patients with hairy cell leukaemia,
with apparent prolongation of survival. IFNa has been
approved for use in chronic myeloid leukaemia,
Kaposi's sarcoma, malignant melanoma and renal
cancer, with response rates of 20-30%. As might be
expected from their physiological role, interferons are
toxic, causing influenza-like symptoms which can be
intolerable.
Inhibitors of key biological processes
Current research is generating many new agents of
potential therapeutic value that interfere with tumour
growth by blocking the function of key pathways in
cancer cells (Fig. 29.5 and see Ch. 26).
• Antibodies. Herceptin is a monoclonal antibody directed
against the HER2 protein, a growth factor receptor
HERCEPTIN
I R ESS A
HER2
GLEEVEC
FARNESYL
TRANSFERASE
INHIBITOR (FTI)
Intracellular signals
influence activity of
cytoplasmic proteins
V
Enhance survival. Gene expression
motility etc. Cell division
Fig. 29.5 Simple growth pathways with sites of action of selected novel biological anticancer agents. A growth
factor binds to a specific ceil surface receptor, generating intracellular signals that activate cytoplasmic proteins.
Depending on the signal, this may lead directly to increased resistance to killing, increased motility, changes in
attachment to other cells or substratum. Activation of cytoplasmic signalling cascades also leads to changes in gene
expression (i.e. switching on/off protein production from specific genes) and changes in the rate of progression
through the cell cycle (i.e. faster/slower growth). The sites of action of Herceptin, a monoclonal antibody to HER2 (a
growth factor receptor), and of Iressa and Gleevec, small molecule inhibitors of the enzyme activity of the epidermal
growth factor receptor (EGFR) and BCR-ABL, respectively, are shown. Farnesyl transferase inhibitors are agents that
block the attachment to the cell membrane of ras protein, a specific signalling intermediate, so inhibiting ras
activation and thus blocking ras-mediated proliferation.
294
CANCER CHEMOTHERAPY
29
expressed by -20% of breast cancers but not by normal
cells. The antibody is generated in mice but has been
'humanized' to avoid triggering immune responses to
mouse proteins. Herceptin has been in clinical use for
several years and has significant anticancer activity in
patients whose breast tumours are strongly HER2 posi-
tive. It can enhance response to cytotoxic drugs such as
taxanes, and is now being assessed as adjuvant therapy-
Like most new treatments, it is very expensive, and it can
cause cardiotoxicity, but it is an extremely valuable new
drug in the treatment of aggressive breast cancer. Several
other antibodies have been shown to have objective anti-
cancer activity, including anti-CD20 for B-cell lym-
phomas and edrecolomab (Panorex) for colorectal cancer.
Small molecule inhibitors. Chemical inhibitors are gener-
ally more successful drugs than antibodies; the latter
are large molecules that require administration by
intravenous infusion, and generally penetrate poorly
into tumours. In contrast, chemical inhibitors are small
molecules that penetrate well, they can be modified to
improve characteristics of specificity, stability, solubil-
ity, etc., and they can often be administered orally. A
recent success story is Gleevec (STI-571), rationally
designed as a small molecule inhibitor of the enzyme
activity of the BCR-ABL fusion protein that is produced
as a result of the chromosomal translocation character-
istic of chronic myeloid leukaemia (CML). Gleevec has
recently been shown to have dramatic anticancer activ-
ity in patients with CML. Iressa is a small molecule
inhibitor of the epidermal growth factor receptor
(EGFR); it has anticancer activity in cancers of the lung
and colon that express high levels of the EGFR. Many
other small molecule inhibitors are currently being
developed, including those that influence the activity
of cytoplasmic signalling pathways and regulation of
gene expression (Fig. 29.5).
Gene therapy. Although cancer often results from defects
in multiple genes, it may be possible to influence its
course by altering the expression of individual genes.
Strategies include replacement of a missing tumour
suppressor gene, inhibition of production of an onco-
gene (see Ch. 26), introduction of genes that cause the
cancer cell to convert a prodrug to a toxic product, and
production of proteins that enhance the host immune
response. Many trials are currently evaluating such
approaches, and some trials are reporting clinical activ-
ity, but at present these remain in the realms of research.
NON-SURGICAL TREATMENT OF
COMMON CANCERS
fr^^^:^5^£^
Anticancer treatments are particularly demanding and
have potentially serious side-effects. You must confirm
the diagnosis histologically before treatment begins, and
ensure that patients understand why each treatment is
offered and what it is intended to achieve. In the treat-
ment of early, curable cancers, ensure that patients
understand what sort of survival benefit may accrue
from the multiple treatment modalities on offer. In the
management of metastatic common cancers, you must
unfortunately explain that chemotherapy cannot cure,
nor with certainty prolong life, but may shrink tumours
temporarily and so give symptom relief. See Chapters 27
and 28 for more information on cancer surgery and
radiotherapy.
Breast cancer
Early breast cancer is treated surgically (see Ch. 27).
Analysis of the resected specimen indicates the main
prognostic factors: tumour size, grade, nodal involvement
and tumour expression of oestrogen receptor (ER) and
progesterone receptor (PgR)- Patients at risk of
micrometa static disease include those with large or high
grade tumours and /or involved axillary lymph nodes.
These patients should be offered adjuvant or neoadjuvant
chemotherapy (Fig. 29.6). For patients aged <50 with
involved nodes, adjuvant chemotherapy leads to a 12%
improvement in 10 year survival, from 41% to 53%. The
benefit is less in patients with node-negative tumours and
those aged over 50. Patients should have radiotherapy
after breast-conserving surgery to reduce the risk of local
recurrence. If the tumour was ER positive, patients
should be offered tamoxifen 20 mg daily for 5 years.
Tamoxifen should not be used in patients with ER-
negative tumours. The timing of these treatments is
shown in Figure 29.6, and the magnitude of the benefit is
summarized in Table 29.2. You will need to explain the
plan to patients during admission for surgery. Reassure
them that they will be given effective antiemetics to
combat nausea, that they may temporarily lose their hair
(depending on the chemotherapy offered), and that radio-
therapy can cause local skin soreness. The whole
treatment plan is long, tiring and daunting, especially
if reasons for giving each component are not clearly
understood.
Metastatic breast cancer can be treated with endocrine
therapy and /or chemotherapy. Patients may work their
way through a range of different regimens and agents,
depending on the pattern of disease. Radiotherapy is
useful for controlling local symptoms, for instance due to
bone or brain metastases. Endocrine therapy such as
tamoxifen or anastrozole is a good option for patients
with slow tempo ER-positive disease involving the skin,
lymph nodes and /or bones. Rapid tempo disease, espe-
cially involving the viscera, for example lungs or liver,
should be treated with chemotherapy. Many single agents
295
MALIGNANT DISEASE
Diagnosis
ADJUVANT CHEMOTHERAPY
Surgery
t r r
1 2 3
ER +ve: TAMOXIFEN for 5yr
TT ♦ ▼¥▼▼¥
RADIOTHERAPY
1 I 1 T 1 1 1
7 8 9 10 11 12 13 14
Months
NEOADJUVANT
CHEMOTHERAPY
Diagnosis
Surgery
ADJUVANT
CHEMOTHERAPY
ER +ve: TAMOXIFEN for Syr
I I I I 1 I I I I I
RADIOTHERAPY
1 T
2 3 4
6
7 8
Months
1 1 f < 1
9 10 11 12 13 14
Fig. 29.6 Treatment of early breast cancer. Patients at risk of recurrence after surgery should be offered adjuvant
chemotherapy (upper panel), usually 4-6 cycles of an anthracycline-containing combination (e.g. doxorubicin plus
cyclophosphamide) or CMF (cyclophosphamide, methotrexate, 5FU). Patients with large tumours or those at very high
risk of recurrence (e.g. high grade tumour) may be offered neoadjuvant chemotherapy (lower panel). This is given
before surgery, with the aim of controlling micrometastatic disease and shrinking the tumour, enabling more
conservative surgery. The timing of endocrine therapy and radiotherapy is also shown. ER, oestrogen receptor.
and combinations have activity in breast cancer but the
objective response rates are often no more than 20-50%.
In general, as with many tumour types, responders live
longer than non-responders, but responses are often
short-lived, so weigh these benefits against the adverse
effects in non-responders.
Lung cancer
A small proportion of patients with non-small cell lung
cancer (NSCLC) may be cured by operation, and occa-
sionally by radical radiotherapy if surgery is inappropri-
ate or is refused by the patient. However, 35-65% of
patients suffer recurrent disease within 5 years of appar-
ently curative resection. Meta-analysis of many trials sug-
gests a small but significant benefit from chemotherapy
given before or after surgery or radiotherapy. Fit patients
with metastatic disease can be offered combination
chemotherapy; responses occur in 20-60% and are asso-
ciated with symptomatic improvement and modest
survival benefit.
Small cell lung cancer (SCLC) has usually metastasized
at the time of presentation. Even in patients with limited
disease, such as a tumour confined to one hemithorax,
there is a high risk of micrometastases, and so all patients
who are fit enough should be offered combination
chemotherapy. Unlike most common solid tumours,
SCLC is highly chemosensitive and 70-85% of patients
respond to combination chemotherapy; however, most
relapse with drug-resistant disease, and only a very few
(~8% with limited disease, 2% with extensive disease)
survive 5 years.
Cancers of the gastrointestinal tract
Localized carcinomas arising in the oesophagus and
stomach are treated surgically (see Ch. 27); however
only 40% of patients are eligible for potentially curative
resection, and recurrence rates are high. Recent evidence
suggests that the survival of high risk gastric cancer
patients can be significantly improved with postoper-
ative irradiation and concurrent 5FU. Fit patients with
advanced or recurrent adenocarcinoma should be
offered chemotherapy. Compared with intermittent
conventional dose 5FU, response rates are significantly
better with continuous low dose infusional 5FU com-
bined with cisplatin and epirubicin. Pancreatic cancer is
unfortunately highly chemoresistant, and most patients
are too unfit for systemic treatment because of advanced
disease at presentation.
296
CANCER CHEMOTHERAPY
I*
29
Table 29.2 Benefits of adjuvant
therapy for
early
breast cancer
Subgroup treatment
Relapse-free(%)
Risk reduction
Survival (%>
Risk reduction
Node -ve Tamoxifen*
79.2
14,9
78.9
5.6
Control
64,3
73.3
Node +ve Tamoxifen*
59.7
15.2
61.4
10.9
Control
44, S
50.6
<50 years
Node -ve Chemotherapy 1
683
10,3
77.6
5.7
Control
58.0
71.9
Node +ve Chemotherapy*
47.6
15.4
53.8
12.4
Control
32.2
41.4
50-69 years
Node -ve Chemotherapy*
65,6
5,7
71.2
6,4
Control
59.9
64.8
Node +ve Chemotherapy'
43.4
54
4S.6
2,3
Control
38.0
463
TabJe shows figures at 10 years for: percent of patients free of relapse; percent surviving (including mortality
from any cause); and reduction in risk of relapse and death.
*Oata for -5 years tamoxifen treatment in patients with tumours that were oestrogen receptor-positive or
unknown.
*Data for patients involved in trials of polychemotherapy, including CMF {cyclophosphamide, methotrexate, 5FU)
and anthracydine-containing regimens. There was clear benefit from chemotherapy in young women (<50 years)
especially those with node-positive tumours {Early Breast Cancer Trialists* Collaborative Group, 1998a, b), A more
recent analysis suggested that young women (<50 years) gained an average of approximately 10 months of
relapse-free survival, and 5 months of overall survival, compared with patients receiving no adjuvant
chemotherapy. These benefits significantly outweighed the toxicity of chemotherapy. Benefits in older women
{50-69 years) were atso significant, though smaller, and outweighed the toxicity burden to a lesser degree (Cole
et at 2001).
Adjuvant 5FU-based chemotherapy has been shown to
improve survival after surgery for localized colorectal
cancer, and is now standard treatment for patients with
Dukes' C colon cancer (see Ch. 27). In metastatic disease,
20% of patients respond to 5FU, with improvement in
tumour-associated symptoms; several studies have
shown survival benefit. Newer drugs with activity in
colorectal cancer include capecitabine, an orally active
prodrug which is converted in the body to 5FU,
irinotecan, a topoisomerase I inhibitor, and oxaliplatin, a
cisplatin analogue.
Urological tumours
Renal cancer can be cured only by complete resection. If
technically feasible, nephrectomy may also confer sur-
vival benefit and symptom relief in fit patients with low
volume metastatic disease. Metastatic renal cancer is
resistant to hormone therapy and cytotoxic drugs.
Biological therapy with IL-2 or IFNa offers a chance of
inducing response, but only in 15-20% of patients.
Superficial bladder cancer is treated surgically, and
localized invasive bladder cancer is managed by surgery
and /or radiotherapy. In approximately 50% of patients
with advanced bladder cancer a response can be induced
with combination chemotherapy, usually including cis-
platin, although this may be problematic if renal function
is compromised.
Organ-confined prostate cancer can be cured by radical
surgery or radiotherapy, either external beam or brachy-
therapy, but metastatic disease is incurable. Most patients
(80%) respond to endocrine therapy, using an LHRH
analogue or an antiandrogen, or the two combined -
'total androgen blockade 7 . Tumour responses are associ-
ated with improvement in symptoms such as bone pain,
and a fall in the tumour marker prostate-specific antigen
(PSA, see Ch. 30). Unfortunately, all tumours become
androgen-resistant, usually after 12-18 months of
endocrine therapy. At this point there may be minor
symptomatic improvement with oral steroids or mito-
xantrone, but metastatic prostate cancer is essentially
chemoresistant.
297
29 \
MALIGNANT DISEASE
Gynaecological cancers
Early stage cervical cancer can be treated with radical
surgery or radical chemoradiation. There is a high risk of
recurrence in those with positive lymph nodes, para-
mesial invasion or positive resection margins. If these
patients are fit enough they should be offered postoper-
ative radiotherapy and concurrent cisplatin chemother-
apy, which have recently been shown to significantly
prolong survival. Advanced cervical cancer is treated
with irradiation, and recurrent disease may respond tem-
porarily to chemotherapy
Patients with ovarian cancer often present with
advanced disease that has spread within the peritoneal
cavity. This is optimally treated by maximal cytoreductive
surgery - removing all visible tumour, and platinum-
based chemotherapy.
Malignant melanoma
Patients with localized melanoma may be cured by
surgery, and thickness of the primary lesion is the most
important prognostic factor. Patients who experience skin
recurrence near the primary site may be salvaged by
further resection. In the 1960s and 1970s there was a
vogue for regional limb perfusion, usually with melpha-
lan, in patients with skin metastases confined to one limb.
Responses occurred in 40% but were generally short-
lived, with no convincing survival benefit. Many trials
have assessed the role of IFNct as adjuvant treatment in
high risk patients. Recent analyses suggest that low dose
adjuvant interferon confers no survival benefit. High dose
adjuvant interferon does, however, appear to be of benefit
but has significant toxicity. The outlook for patients with
metastatic disease is grim; only -20% of patients respond
to chemotherapy, usually with DTIC (dacarbazine), or to
immunotherapy with IFNct, but these responses are
usually brief and without survival benefit. A small per-
centage of patients obtain durable complete remissions,
most often those with a small tumour burden.
Sarcomas
The outlook for patients with osteosarcoma is signifi-
cantly improved if surgery is followed by immediate
adjuvant chemotherapy, typically using cisplatin,
doxorubicin and high dose methotrexate. This cures
approximately 60% of patients. Neoadjuvant chemo-
therapy is increasingly used as well, to gain control of
micrometastatic disease and to shrink the primary
tumour to facilitate limb-sparing surgery. Pulmonary
metastases are not necessarily incurable; patients
with fewer than six metastases may be salvaged with
second-line chemotherapy, thoracotomy and excision of
metastases. The prognosis of adults with soft tissue sar-
comas is less good: tumours often recur after surgery,
and are relatively resistant to both chemotherapy and
radiotherapy.
Myeloma
In ~75% of cases, patients with myeloma respond to oral
melphalan and prednisolone. Younger, fitter patients
may derive greater benefit from more complex or inten-
sive chemotherapy regimens, such as intravenous combi-
nation chemotherapy or high dose melphalan with bone
marrow transplantation.
NON-SURGICAL TREATMENT OF
HIGHLY CHEMOSENSITIVE CANCERS
Approximately 12% of cancer patients have tumours
that are highly responsive to chemotherapy. These
patients are often young, and even those with advanced
disease may stand a good chance of being completely
cured. Therefore it is essential that they should be
managed in specialist centres by experienced multi-
disciplinary teams, as this has been shown to lead to
improved survival.
Lymphoma
Hodgkin's disease can now be cured in most patients.
The best chance of cure is when the patient first presents,
and disease recurrence worsens the outlook. Patients
with localized disease are treated with radiotherapy (see
Ch. 28), and those with advanced disease are offered
combination chemotherapy. Both chemotherapy and
irradiation are used in defined situations such as a large
mediastinal mass.
Non-Hodgkin's lymphomas (NHLs) are a heteroge-
nous group of conditions for which there is a plethora of
classifications based on cellular, immunological and
molecular criteria. In essence the prognosis is better
when the cellular infiltrate is comprised mainly of small
rather than large cells, and shows evidence of organiza-
tion into a follicular pattern rather than diffuse infiltra-
tion. 'Low grade' lymphomas are generally treated with
intermittent oral chlorambucil plus prednisolone. These
lymphomas often pursue an indolent course with a long
median survival, but cannot be cured. Approximately
30-40% of patients with 'high grade' NHL can be cured
with intravenous chemotherapy, typically with CHOP
(cyclophosphamide, doxorubicin (= hydroxydauno-
rubicin), vincristine (= Oncovin), prednisolone).
298
CANCER CHEMOTHERAPY
29
Germ cell and trophoblastic tumours
Key point
Germ cell tumours are highly curable.
Teratomas limited to the testis can be cured in 80% of
cases by orchidectomy. Combination chemotherapy is
required in those that relapse, and in patients presenting
with poor risk features. Most regimens are intensive,
incorporating cisplatin, etoposide and bleomycin, and
are often highly toxic to the gut, bone marrow, kidneys
and lungs. Surgery may be required after chemotherapy
to excise residual lymph node masses or pulmonary
metastases. Modern combination chemotherapy can
achieve cures in 80-90% of patients, although survival
rates fall to -50—60% in poor prognosis patients with
liver, bone or brain metastases, extreme elevation of
tumour markers a- fetoprotein, human chorionic
gonadotrophin or lactate dehydrogenase, or primary
mediastinal mass.
Seminomas are highly curable. Patients with stage 1
disease can be treated with prophylactic para-aortic irra-
diation or a single dose of carboplatin. Alternatively they
can be managed by surveillance; many will be cured by
surgery alone, and virtually all the 10-15% that relapse
can be cured by chemotherapy or irradiation. Patients
with stage 2-4 disease are treated with chemotherapy,
and the majority are cured.
Choriocarcinoma is a rare tumour which usually
follows a pregnancy resulting in a hydatidiform mole.
Choriocarcinomas are extremely sensitive to chemother-
apy, which can cure virtually 100% of patients with local-
ized disease and over 70% with advanced disease. See
Chapter 30 for more details on the clinical monitoring and
treatment of patients with these tumours.
TALKING TO PATIENTS ABOUT
CANCER
■BSisejs? g!383Sia«5*i
It does not need to be said that a diagnosis of cancer is a
devastating and extremely frightening situation for any
family. You should be aware that the way you talk to
patients and their families can have a huge bearing on
how they view the situation and try to come to terms with
it. Clear, sympathetic and sensitive explanations can help
to minimize the fear, anger and confusion that patients
and their families experience. If people ask direct ques-
tions about their anticancer treatments and prospects of
survival, it usually means that they are ready to hear
straight answers. If you need to talk to patients about
such issues and you are not sure how much they know or
want to know, start by asking what they understand
about the situation. This will let you know what they
have been told (or what they remember - not always the
same thing), and what terminology they are comfortable
with (e.g. lump/tumour/cancer/adenocarcinoma). Then
explain what the situation is as you see it, using and
expanding on the terms they are already familiar with.
Don't use words like 'lesion' or 'neoplasm' which are
meaningless to a non-medic. Then go on to explain what
can be done about the situation.
In patients embarking on complex treatments for early
stage, potentially curable cancer, it is important to be
encouraging and to explain the role of each component of
therapy. If the prospects of long-term survival are poor, it
is best not to be too brutally accurate. For example, the
meta-analyses may suggest that a woman with high
grade breast cancer and more than four positive nodes
has only a 20-30% chance of survival. Knowing this
would inevitably cause severe anxiety that may be hard
to live with, and it may be reasonable in such a case to be
vague about the long-term outlook.
When discussing the prognosis with patients who
have advanced and incurable disease, it is generally
better to be honest. There is never 'nothing that can be
done', and it is important to explain sympathetically
what support and treatments are available. For each
treatment you should highlight the main advantages and
disadvantages, but keep it simple and avoid giving too
much information at once. Outline the chances of
response, and the main side-effects, and be realistic
about the overall benefit. You could say, for example:
This treatment has a 40% chance of shrinking the
tumour and helping you to feel better. But I am afraid it
is not going to cure you, and the cancer will catch up
with you in the end/ This will give the patient the oppor-
tunity to ask, if they wish, the $64 000 question 'How
long have I got?' Explain that this is impossible to
answer with accuracy. You could reply 'Months, perhaps
many months or a few years' to a fit patient with
metastatic cancer, but an ill patient may expect only a
few weeks or months. If a patient is clearly terminally ill
and could die within a few days or weeks, assess
whether the patient can cope with this information, and
gain his/her permission to tell the family. Many relatives
feel a lasting sense of bitterness if they were unaware up
to the last moment that death was imminent. Patients
and their families usually give fairly clear verbal and
non-verbal clues to indicate how much of this sort of
information they can take at any one time. See Chapter
47 for a discussion of the principles of palliative care and
the effective use of analgesia.
299
29
MALIGNANT DISEASE
EVALUATION OF NEW ANTICANCER
DRUGS
^$$x&?^&
There is intensive laboratory -based effort to address the
urgent need for more effective anticancer therapy. These
may be derivatives of standard cytotoxic drugs, such as
oxaliplatin and capecitabine, which are related to cis-
platin and 5FU, respectively. Increasingly, research is
generating new biological agents. Drugs that block key
biological processes can be sought by large scale screen-
ing, such as that conducted at the National Cancer
Institute in the USA using assays suitable for processing
large numbers of compounds. Alternatively the first step
can be the identification of a biological target, which
could be a process or a specific protein, and a drug is
designed that is capable of inhibiting the function of that
target. Potential treatment targets include not only the
genes that regulate growth but also those that influence
motility, invasion, cell-cell interaction, the formation of
new blood vessels (angiogenesis), resistance to killing,
and the ability to evade immune recognition (see Ch. 26).
If a drug is shown to be effective in animal models of
cancer, the next step is to assess its effect in clinical trials
(Table 29.3).
Table 29.3 Organization of new drug trials
Phase I Phase II
Phase III
Conducted in a range of tumour types. Assess;
■ Maximum tolerated dose
■ Toxicity
■ Pharmacology
* Therapeutic effect
Assess:
* Therapeutic effect in specific
tumour types
* Dose-response relationship
Controlled clinical trials:
• Compare with existing
standard therapy
New drug trials are conducted in distinct phases to assess toxicity and efficacy. It can take up to 10-15 years for a
promising new agent to complete preclinical evaluation and the standard phase I, II and III clinical trials.
Summary
• Chemotherapy and radiotherapy should be
used only in patients with confirmed
histological diagnosis of malignancy.
• Adjuvant chemotherapy definitely
increases the proportion of patients cured
after surgery for cancers of the breast,
colon and osteosarcoma, and may have a
similar effect in cancers of the stomach,
lung and cervix.
• Chemotherapy can cure patients with
advanced teratoma, lymphoma, and some
patients with SCLC and ovarian cancer.
• Chemotherapy and endocrine therapy are
only palliative for most patients with
metastatic disease.
• New biological therapies hold promise for
the future.
References
Cole BF, Gelber RD, Gelber S, Coates AS, Goldhirsch A 2001
Poly chemotherapy for early breast cancer: an overview of the
randomised clinical trials with quality-adjusted survival
analysis. Lancet 358: 277-286
Early Breast Cancer Trialists' Collaborative Group 1998a
Tamoxifen for early breast cancer: an overview of the
randomised trials. Lancet 351: 1451-1467
Early Breast Cancer Trialists' Collaborative Group 1998b
Polychemotherapy for early breast cancer: an overview of the
randomised trials. Lancet 352: 930-942
Further reading
Nature Reviews Cancer has regular reviews on new therapeutics, for
example:
Greenwood E 2002 Therapeutics: stop signals. Nature Reviews
Cancer 2: 640
Hurley LH 2002 DNA and its associated processes as targets for
cancer therapy. Nature Reviews Cancer 2: 188-200
300
CANCER CHEMOTHERAPY
29
McCormick F 2001 Cancer gene therapy; fringe or cutting edge?
Nature Reviews Cancer 1: 130-141
De Vita V, Hellman S, Rosenberg S (eds) 2001 Cancer: principles
and practice of oncology, 6th edn. Lippincott Williams and
Wilkins, Philadelphia. Extremely comprehensive textbook with
good references to primary sources.
Souhami R, Tobias J (eds) 2002 Cancer and its management, 3rd
edn. Blackwell Science, Oxford. Medium length texbook,
excellent general read.
Therasse P, Arbuck SG, Eisenhauer EA et al 2000 New
guidelines to evaluate the response to treatment in solid
tumors. Journal of the National Cancer Institute
92(3):205-216
Useful links
www.cancerbacup.org.uk This is an extremely useful resource
to pass on to patients for information, practical advice and
support.
www.cancer.gov/cancer_information/pdq The National Cancer
Institute's 'Physicians Data Query' site, with pages for medical
stuff and patients. Very detailed information on management of all
types of cancer including all relevant references, levels of proof,
updated monthly.
www.cancerresearchuk.org Informative UK site for health care
professionals and patients, includes general and tumour site specific
information on incidence, diagnosis and treatment, downloadable
leaflets, etc.
301
Tumour markers
G. J. 5. Rustin, A. E. Guppy
w
Objectives
Appreciate the potential uses of circulating
tumour markers.
Recognize which tumour markers are most
commonly elevated in particular tumours.
Understand how tumour markers can be
used to affect management of certain
tumours.
Lead to more appropriate requesting of
tumour marker measurements.
INTRODUCTION
Tumour markers are substances present in the body in a
concentration that is related to the presence of a tumour. A
tumour marker does not have to be tumour specific. It may
be secreted or shed into blood and other body fluids or
expressed at the cell surface in larger quantities by malig-
nant cells than by non-malignant cells. Tumour markers
can be detected either by measuring the concentration of
the marker in body fluids (usually by immunoassay) or by
detecting the presence of the marker on the cell surface in
paraffin sections or fresh biopsies (by immunohistochem-
istry). This chapter examines critically those situations
where estimation of circulating tumour marker levels may
be of clinical value.
DEFIMTIONS^^^
The terms most commonly used to describe the useful-
ness of a tumour marker are defined in Table 30.1.
Sensitivity is a measure of how commonly a tumour
marker level is elevated in the presence of that particular
tumour. Specificity measures the proportion of patients
without tumour who have normal marker levels, and are
therefore the true negatives. The positive predictive value
is the percentage of positive results (i.e. elevated marker
levels) which are true positives. An ideal tumour marker
would have 100% sensitivity thus detecting all cases of a
particular tumour, and 100% specificity, being elevated
only in the presence of that tumour and not in any other
situation.
POTENTIAL USES OF TUMOUR
MARKERS
The potential clinical uses of tumour marker estimation
are:
• Screening
• Diagnosis
• Prognostic indicator
• Monitoring therapy
• Early diagnosis of relapse.
Examples of these uses will be given for the cancers
where tumour markers are currently of greatest value.
Although they will not be discussed in any further detail
Table 30.1 Terms used to describe tumour markers
Tumour
Present
Absent
Assay positive TP
Assay negative FN
Sensitivity =
Specificity
Positive predictive value =
Negative predictive value =
TP
TP + FN
TN
FP + FN
TP
TP + FP
TN
FN + TN
FP
TN
x 100
x 100
x 100
x 100
TR true positive; FP, false positive; FN r false
negative; TN, true negative.
302
TUMOUR MARKERS
30
in this chapter, the existence of cell surface tumour
markers is being exploited to localize a tumour either for
imaging purposes, using a radiol a belled antibody, or as a
treatment modality, using antibodies to carry radioactiv-
ity or toxins selectively to the tumour.
REVIEW OF THE USE OF TUMOUR
MARKER ESTIMATION IN THE
MANAGEMENT OF PARTICULAR
TUMOURS
Gestational trophoblastic tumours (GIT)
The role of human chorionic gonadotrophin (hCG) in the
management of GTT comes closest to the ideal use of a
tumour marker. hCG is a glycoprotein produced by
trophoblast cells. The ct-subunit is identical to that of
follicle-stimulating hormone (FSH), luteinizing hormone
(LH) and thyroid-stimulating hormone (TSH), but the
C-terminal end of the p-subunit is unique to hCG and
provides the basis of the specific immunoassay There are
many different assays for hCG available. It is essential to
know whether the assay in use locally recognizes just the
p-subunit or the intact complete hCG molecule, as they
can give quite different results.
Diagnosis and screening
Elevated levels of hCG are found with as few as 10 5
trophoblast cells, but elevated serum hCG levels are also
found in normal pregnancy, in ectopic pregnancy, in
patients with germ cell tumours and, occasionally, in
patients with non-germ-cell tumours. Pelvic ultrasound
examination therefore remains the best method for diag-
nosing hydatidiform mole. The great sensitivity of hCG,
however, allows it to be used to screen a high risk popu-
lation. The first national screening programme for any
cancer was set up in 1972 so that, following a diagnosis of
hydatidiform mole, all patients are centrally registered.
Patients are then followed using serial hCG measure-
ments in blood or urine. This screening allows those
patients with persistent trophoblastic disease after evacu-
ation of hydatidiform mole to be detected on the basis of
plateauing or rising tumour markers before any clinical
evidence of disease develops (Bagshawe et al 1986).
Prognosis and monitoring response to
treatment
Since hCG levels in patients with GTT reflect the total
body burden of viable tumour, the level is a major factor
in deciding whether a patient fits into a good or poor
prognostic group. In patients with GTT, serial hCG
estimation is used to monitor response to chemotherapy
and to detect the development of drug resistance. The
hCG value may initially increase after starting treatment,
possibly due to tumour lysis or to increased syncytial dif-
ferentiation induced by the therapy. The hCG level then
falls at a rate which is a function of metabolic clearance
and the rate of synthesis. Plateauing of hCG values or
rising values during the course of chemotherapy indicate
the development of drug resistance, and need to change
chemotherapy.
Detection of recurrence
Serial measurement of hCG will detect any recurrence of
GTT with 100% sensitivity. The accurate measurement of
hCG in urine, which is stable in the post, increases the
ease of monitoring and obviates the need for frequent
hospital visits. A rise in hCG is not, however, diagnostic
of recurrent disease, and a new pregnancy must always
be considered and ruled out by ultrasound examination.
Patients who have had a hydatidiform mole have a
slightly increased risk of choriocarcinoma after any sub-
sequent pregnancy and should have further hCG estima-
tions at 4 and 12 weeks postpartum.
Germ celt tumours
a-Fetoprotein (AFP) and hCG are elevated, either singly
or in combination, in more than 80% of patients with
disseminated non~seminomatous germ cell tumours
(NSGCT) and in approximately 60% of patients with
localized, stage I disease (Bower & Rustin 1996). Other
markers of use in patients with germ cell tumours include
lactate dehydrogenase (LDH), but many laboratories
only measure hydroxybutyrate dehydrogenase (HBD),
which is mostly isoenzyme 1 and 2 of LDH. Placental
alkaline phosphatase (PLAP), although elevated in about
50% of patients with seminomas and in smokers, adds
little to clinical management, as it is rarely greatly elev-
ated and usually falls to normal so quickly on therapy
that it adds little to monitoring (Nielsen et al 1990).
Diagnosis and staging
All patients who are suspected of having a germ cell
tumour should have serum sent for tumour marker esti-
mation before excision of the primary tumour. Patients
whose clinical status could be compromised by a biopsy
(e.g. a patient with severe dyspnoea due to extensive lung
metastases) should be considered to have an NSGCT if
the distribution of the disease is compatible with such a
tumour and there is gross elevation of either hCG or AFP
Elevated hCG is associated with the presence of tropho-
blastic elements in an NSGCT, and can be produced
303
30
MALIGNANT DISEASE
by syncytial giant cells in a pure seminoma. AFP, a
glycoprotein with a molecular weight of 63-70 kDa, is
secreted by the yolk sac element of an NSGCT, and a
patient with an elevated AFP should never be considered
to have a pure seminoma, regardless of the histological
findings.
Failure of tumour marker levels to fall to normal post-
operatively indicates the presence of occult metastatic
disease, even if all other staging investigations are
normal. One further situation in which hCG estimation
may be of diagnostic value is in the detection of brain
metastases. A pretreatment cerebrospinal fluid hCG level
that is more than one-sixtieth the serum hCG level indi-
cates the presence of brain metastases; the normal ratio,
however, does not exclude brain metastases (Bagshawe &
Harland 1976).
Prognosis and staging
Initial tumour marker levels are now recognized as the
single best predictor of failure to achieve complete
response following chemotherapy. An international col-
laborative group has recently proposed a prognostic
classification (Table 30.2) based on an analysis of 5202
patients that found tumour marker levels and the pres-
ence or absence of mediastinal and non-pulmonary, non-
nodal visceral metastases as the important risk factors
(International Germ Cell Collaborative Group 1997).
Monitoring response to treatment
In patients with elevated hCG or AFP, these markers are
the most sensitive method for assessing response to treat-
ment. Although, in general, successful chemotherapy is
invariably accompanied by a fall in serial hCG and AFP
levels, there are two situations in which this may not
occur. Firstly, an initial rise in tumour marker levels may
occur soon after starting the first course of chemotherapy
due to tumour lysis. The second situation is a plateau or
even a rise in AFP levels, despite evidence of response
from all other investigations. This is thought to be due to
AFP production by the liver in response to toxicity and
appears to be more common in those patients receiving
hepatotoxic drugs such as methotrexate and ifosfamide.
The only situation where falling marker levels are not
associated with a decreasing germ cell tumour mass is
when there is enlargement of cystic differentiated tera-
toma. These masses require resection before they become
inoperable.
Early detection of recurrence
All patients with germ cell tumours should continue to
have serial tumour marker estimation after completion of
chemotherapy to detect relapse early The other situation
in which serial marker estimation is invaluable is in
surveillance of patients with stage I disease following
orchidectomy. Close follow-up by clinical examination,
tumour markers, chest X-rays and CT scans will detect
relapse early in the 25-30% of those in whom the disease
is destined to recur and, with adequate treatment, virtu-
ally all patients will be cured. In view of the potential for
tumour markers to double rapidly, it is important that
markers are measured at least monthly, and more fre-
quently if raised.
Gastrointestinal tumours
There are a number of antibodies currently available
which detect antigens expressed by gastrointestinal
tumours. The most widely used are the antibodies which
react with carcinoembryonic antigen (CEA), a 200 kDa
glycoprotein. Assays dependent on monoclonal anti-
bodies include CA 19.9, an antigen derived from a human
colon adenocarcinoma cell line with an epitope (the
portion of an antigen which combines with the antibody
binding site) structurally identical to the sialylated Lewis
A antigen, and CA 50, which is similar but not identical
to CA 19.9. Elevated levels of several other markers such
as CA 72-4 have also been found.
Table 30,2 Tumour markers
in prognostic classification of
germ
cell tumours
■
Marker
AFP (ng ml" 1 )
hCG* (ng ml 1 )
LDH 1 (x N)
Good
Intermediate
Poor
<1000
1000-10 000
>10 000
and <1000
or 1000-10 000
or >10 000
and <1.5
or 1.5-10
or >10
*For hCG, 1 ng ml
T A/, upper limit of
_1 is approximately equal to 5 iu 1 *■.
normal.
304
TUMOUR MARKERS
30
Diagnosis and screening
Serum CEA is elevated in fewer than 5% of patients with
Dukes' grade A colorectal cancer, about 25% of Dukes'
grade B, 44% of Dukes' grade C and about 65% of
patients with distant metastases (Begent & Rustin 1989).
CEA can be elevated not only in cancers of the gastro-
intestinal tract but also in a variety of other conditions,
including: severe benign liver disease; inflammatory
lesions, especially of the gastrointestinal tract; trauma;
infection; collagen disease; renal impairment; and
smoking. The low incidence of high serum CEA levels in
early disease and its poor specificity explain its lack of
value in screening normal populations for colorectal
cancer. The low sensitivity precludes it being useful
even for screening patients with ulcerative colitis or
familial polyposis coli; although these patients are at
high risk of developing colorectal cancer, both condi-
tions may cause raised serum CEA in the absence of
malignancy.
Prognosis and monitoring treatment
A raised preoperative CEA level has been shown to be
associated with a poorer prognosis, but the value of pre-
operative CEA as an independent prognostic factor is
unclear. Serum CEA levels should fall to normal within
4-6 weeks of complete resection of a colorectal carcinoma,
the mean half-life being about 10 days. Levels usually rise
with disease and fall with response to chemotherapy or
radiotherapy. Failure of CEA to fall during radiotherapy
usually indicates the presence of tumour outside the radi-
ation field. Several studies have shown that survival is
longer in patients who have a fall in serum CEA level
during chemotherapy than in those in whom there is no
change or an increased level (Allen-Mersh et al 1987). CA
19.9 is elevated in 75-90% of patients with pancreatic car-
cinomas and is increasingly used to monitor palliative
chemotherapy.
Foilow-up and detection of relapse
In approximately two-thirds of patients with recurrent
colorectal cancer, a rise in serial serum CEA values pre-
dicts recurrence on average 11 months before it becomes
clinically apparent (Begent & Rustin 1989). Surgical resec-
tion of isolated metastases of colorectal cancer has been
advocated. Unfortunately, a randomized, multicentre trial
under the auspices of the Cancer Research Campaign has
failed to show any survival benefit from surgery after
early detection of recurrence by rising CEA levels
(Lennon et al 1994); however, further work is required to
determine whether such patients would benefit from
chemotherapy.
Ovarian cancer
The site and pattern of spread of ovarian cancer make it
very difficult to detect and monitor using conventional
clinical and radiological techniques, so a circulating
tumour marker is potentially very valuable. CA 125 is the
most commonly used tumour marker for ovarian cancer.
CA 125 is found in derivatives of coelomic epithelium,
including pleura, pericardium and peritoneum, but is not
detected in normal ovarian tissue.
Diagnosis
CA 125 is elevated in over 95% of patients with advanced
(stage III or IV) ovarian cancer, but in less than 50% of
patients with stage I disease (Bast et al 1983). However, an
elevated CA 125 is not diagnostic of ovarian cancer.
Levels above 30 iu ml" 1 are frequently seen during the first
trimester of pregnancy, in patients with endometriosis or
with cirrhosis, especially if ascites is present, and in 1% of
healthy controls. In addition, over 40% of patients with
advanced non-ovarian intra-abdominal malignancies
have elevated CA 125 levels. None the less, in a patient
suspected of having ovarian cancer, the presence of an
elevated CA 125 should prompt you either to refer the
patient to a gynaecological oncologist or to perform the
surgery through a more extensive midline incision to
allow adequate debulking of tumour.
Screening
Despite the low sensitivity of CA 125 for potentially
curable stage I tumours, large screening studies have been
performed. One study at the Royal London Hospital
measured serum CA 125 in 22 000 postmenopausal well
women. Those women who had CA 125 levels above
30 iu ml -1 underwent pelvic ultrasound, and if that was
positive a laparotomy was performed. In all, there were
11 confirmed cases of epithelial ovarian cancer (true posi-
tives) and 11 cases in whom laparotomy did not reveal an
ovarian tumour (false positives). Of note, however, is the
fact that only 3 of the 11 patients with screen-detected
ovarian cancers had stage I disease (Jacobs et al 1993). A
large randomized trial is currently investigating whether
serial CA 125 screening with ultrasound in patients with
elevated or rising levels leads to improved survival. New
research tools such as the use of proteomic (the protein
profile) patterns in serum of patients with ovarian cancer
which have both an increased specificity and sensitivity
may have a future role in screening (Petricoin et al 2002).
However until further work has been conducted, screen-
ing for ovarian cancer should not be offered to women
outside a clinical trial unless there is a high risk of
familial ovarian cancer.
305
30
MALIGNANT DISEASE
Assessing completeness of excision
In order to decide optimum postoperative management,
it is important to know whether one is dealing with a
patient with completely excised stage I disease, or
whether the patient has residual tumour after surgery. A
persistently elevated CA 125 after oophorectomy for sus-
pected stage I disease is definite evidence of residual
tumour.
Prognosis and response to treatment
Very high CA 125 levels prior to surgery are associated
with a worse prognosis, but knowledge of this is
unlikely to lead to any alteration in management. The
exception is in women with stage I disease where a pre-
operative level > 65 iu ml -1 has been shown to be a
powerful adverse prognostic indicator (Nagele et al
1995). Such patients are candidates for chemotherapy
rather than surveillance. Several groups have shown that
the CA 125 level after one, two or three courses of
chemotherapy, a long half-life or greater than seven-fold
fall are the most important prognostic factors for sur-
vival. Prognostic information based on CA 125 should
not be used to decide therapy as in nearly 20% of cases
where CA 125 predicts a poor prognosis the patient has
no cancer progression in the next 12 months (Fayers et al
1993).
Definitions for response based on serial CA 125 esti-
mations have been proposed (Rustin et al 1995) and
appear more accurate than scans for monitoring therapy.
For use in clinical trials they have to be very precise and
use mathematical logic in a computer program. Put
simply, response according to CA 125 has occurred if
either of the following criteria are applicable:
• Either 50% response has occurred if there is a 50%
decrease in serum CA 125 levels. There must be two
initial elevated samples. The sample showing a 50% fall
must be confirmed by a fourth sample (requires four
CA 125 levels).
• Or 75% response has occurred if there has been a serial
decrease in serum CA 125 levels of more than 75% over
three samples (requires three CA 125 levels).
(In each the final sample has to be at least 28 days after
the previous sample.) These definitions are particularly
useful for clinical trials, where they indicate which new
treatments are active more easily and cheaply than the
use of standard response criteria.
Detection of progression or relapse
A serial rise of CA 125 of more than 25% appears the most
accurate method of predicting progression of ovarian
cancer during therapy and could lead to ineffective, toxic
and expensive therapy being withheld. A confirmed dou-
bling from the upper limit of normal during follow-up
predicts relapse with almost 100% specificity. There is
controversy about the role of serial CA 125 measure-
ments during follow-up in asymptomatic patients, with
the anxiety from knowing CA 125 levels often inducing
CA 125 psychosis. Although the use of CA 125 estimation
to define progression may reduce the number of radio-
logical investigations performed, there is no evidence at
present that early reintroduction of chemotherapy or
searching for a resectable site of relapse produces any
survival benefit A large Medical Research Council
(MRC) and European Organization for Research and
Treatment of Cancer (EORTC) trial is currently withold-
ing all serial CA 125 results from clinicians and patients
during follow-up until the levels double. Patients are
then randomized between immediate therapy or the
clinician not being informed of the result so the patient
continues on observation. Until the results of this trial
are available, monitoring by CA 125 during follow-up
should be discouraged.
Prostate cancer
Prostate-specific antigen (PSA) is the most useful tumour
marker in patients with prostate cancer. PSA is a serine
protease, produced by prostate epithelium, with the
function of liquefying the gel which surrounds spermata-
zoa to enable them to become fully mobile. In serum, PSA
is found either free or complexed to proteins. PSA esti-
mation has superseded that of prostatic acid phosphatase
as it is elevated in a higher proportion of men with
prostate cancer.
Diagnosis, screening and staging
Elevated levels of PSA (>4 ng ml" 1 ) occur in about 53% of
men with intracapsular microscopic prostatic cancer, and
77% of men with intracapsular macroscopic prostatic
cancer, but can also occur in 30-50% of men with benign
prostatic hypertrophy (BPH), a condition common in men
of similar age group to those who develop prostate cancer
(Dorr et al 1993). The combination of PSA and digital
rectal examination, followed by prostatic ultrasound in
patients with abnormal findings, is commonly used for
screening in the USA but is not recommended in the UK
as there is so far no evidence of survival benefit from early
detection of prostate cancer. There is a vocal debate
raging, with those who advocate screening stating that an
individual with early prostate cancer may be cured by
radical surgery or radiotherapy. Those against screening
306
TUMOUR MARKERS
30
point out that, despite a 9% chance of developing clinical
prostate cancer, there is only a 1 % chance of dying from
it and we cannot predict which cancers will be aggressive,
so most patients will suffer the side-effects of therapy
without any benefit. Furthermore, about 40% of those
patients with PSA levels of 4.0-9.9 ng ml -1 at screening
will already have tumour spread outside the prostate
(Catalona et al 1991).
Several methods are being used to improve diagnostic
specificity. The best appears to be the measurement of
the ratio of free to total PSA, as more of the PSA is
protein bound in patients with prostate cancer than in
those with BPH. The ratio of free to total PSA is low
(about 10%) in prostate cancer, compared with >16% in
BPH and prostatitis. Using this ratio increases the speci-
ficity for diagnosing prostate cancer from 30% to 61%
(Froschermaier et al 1996). PSA density and PSA density
of the transition zone rely on ultrasound size estimations
leading to lack of precision, but some centres have
shown this measurement to improve specificity. Another
method is based on the observation that PSA levels
generally rise by more than 20% per annum in cases of
malignancy. The PSA velocity calculated from serial
levels can improve specificity but at the expense of
delaying diagnosis.
PSA is less reliable than transurethral ultrasound in
the detection of capsular invasion. A recently studied
research tool is the use of the ultrasensitive reverse tran-
scriptase polymerase chain reaction to detect PSA gene
expression on circulating prostate cells. This technique
might improve staging by detecting preoperatively those
patients with extracapsular extension who do not benefit
from radical surgery. Patients with PSA levels of
<20 ng ml" 1 can be assumed to have no bone metastases
and do not necessarily need bone scans. However, not all
patients with a PSA of >20 ng ml" 1 will have distant
metastases. Lymph node metastases are usually associ-
ated with elevated PSA.
Prognosis, monitoring response and
detection of recurrence
As the PSA level correlates with prostatic volume and
tumour differentiation, it is not surprising that a high pre-
treatment PSA is associated with a poor prognosis. PSA
levels fall rapidly to normal after complete removal of
tumour by radical prostatectomy, although the rate of fall
is slower after successful radiotherapy or endocrine
therapy. A serial rise in PSA frequently precedes other evi-
dence of disease progression in the patient with a past
history of prostate cancer. The development of back pain
in the presence of an elevated PSA level suggests the
development of bone metastases.
Hepatocellular carcinoma
Serum AFP is elevated at presentation in 50-80% of UK
patients with hepatocellular carcinoma (HCC). Although
HCC is one of the most common malignant tumours in
the world today, the relatively low incidence in the UK
does not justify general population screening, although
such screening may be justified in areas, such as China,
with high incidence populations. In the UK, serial AFP
estimation and ultrasound examination can be justified,
however, for selective screening of high risk populations
(i.e. patients with cirrhosis, chronic hepatitis B or
haemochromatosis) because patients who have successful
resection of a solitary, screen-detected tumour have a
higher chance of long-term survival. Modest elevations of
AFP occur in about 20% of patients with hepatitis, cir-
rhosis, biliary tract obstruction and alcoholic liver disease
and in up to 10% of patients with hepatic metastases.
Despite these caveats, a massively elevated AFP in a
patient with known cirrhosis is virtually diagnostic of
HCC.
Breast cancer
A variety of tumour markers have been studied in
patients with breast cancer, including CEA and tissue
polypeptide antigen (TPA) and several polymorphic
epithelial mucin markers (HMFG1, HMFG2, MSA, MCA,
CAM-26, CAM-29 and CA 15-3). The most widely inves-
tigated mucin marker in breast cancer is CA 15-3. The
commercially available CA 15-3 kit utilizes a sandwich
technique which employs two monoclonal antibodies: the
115D8 antibody as the capture antibody and the DF3 anti-
body as the tracer antibody.
Diagnosis and screening
Although elevated levels of CA 15-3 are found in
55-100% of patients with advanced breast cancer, serum
CA 15-3 is raised in only 10-46% of patients with
primary breast cancer and in about 10% of patients with
early (T1/2N0M0) operable disease. As 2-20% of
patients with benign breast disease have elevated levels,
it is clear that mucin assays such as CA 15-3 are lacking
in both specificity and sensitivity as a screening tool. No
other tumour marker or combination of markers con-
tribute to the diagnosis of breast cancer (Nicolini et al
1991).
Prognosis and monitoring response to
treatment
Elevated preoperative levels of CA 15-3 have been
shown to be associated with a poorer prognosis
307
30
uauuaiiiiiiuutfSBGttiita
MALIGNANT DISEASE
(Kallioniemi et al 1988). However, this may well be due
to the association between CA 15-3 and tumour burden,
and there is no convincing evidence to date that
measurement of CA 15-3, or any other tumour marker,
provides significant independent prognostic informa-
tion. Although tumour marker levels can fall with reduc-
tion in tumour burden following systemic therapy, the
variation between patients makes tumour markers
unreliable for assessing response.
Early detection of relapse
The observation that over 60% of patients who develop
recurrent breast cancer have raised levels of CA 15-3 sug-
gests a potential value in early detection of recurrence.
The use of a panel of tumour markers might further
increase the pick-up of recurrent disease. However, it is
questionable whether such early detection of relapse will
alter survival and thus whether the patient will benefit.
Other cancers
• Neuron-specific enolase is elevated in many patients
with advanced small cell lung cancers and in children
with neuroblastoma, where it is used for screening.
• Paraprotein levels are very important in the manage-
ment of patients with myeloma, where ^-microglobulin
may be of prognostic value.
• Carcinoid tumours can be monitored by urine levels of
5-hydroxyindoleacetic acid (5HIAA), and polypeptides
such as gastrin or glucagon are useful in the manage-
ment of rare gastrointestinal tumours.
• Squamous cell carcinomas are associated with elevated
levels of squamous cell carcinoma antigen (SCC) as
well as cytokeratin fragments. SCC and CA 125 give
valuable prognostic information in patients with cervi-
cal carcinoma, and may indicate relapse before scans.
• Calcitonin and calcitonin-gene-related peptide are used
in the diagnosis and screening for medullary thyroid
carcinoma.
• Serum S-100 and reverse transcriptase polymerase
chain reaction to detect mRNA of tyrosinase on circu-
lating melanoma cells are being studied for staging and
following patients with melanoma.
There are many other markers not mentioned, either
because they are not considered to be of clinical value or
because information related to value is inadequate. Many
cytokines, growth factors, oncogenes and oncogene
products are being investigated as tumour markers, and
some may well prove to be useful. Despite many claims,
there are no markers that are of use as general cancer
screens.
Summary
• Tumour markers may have a high
sensitivity in patients with advanced
cancer but most have a low sensitivity in
patients with early stage cancer.
• When using a tumour marker to help in
diagnosis it is essential to know its
specificity.
• The potential uses of tumour markers are
best demonstrated by hCG, where it is
used for screening, diagnosis, determining
prognosis, monitoring therapy and in
follow-up of patients with gestational
trophoblastic disease.
• The most commonly used tumour markers
are PSA for prostate cancer, CA 125 for
ovarian cancer, CEA for colorectal cancer,
and hCG and AFP for germ cell tumours.
• Before requesting detection of a tumour
marker, always consider whether the result
would alter your management.
References
Allen-Mersh TG, Kemeny N, Niedzwiecki D et al 1987
Significance of a fall in serum CEA concentration in patients
treated with cytotoxic chemotherapy for disseminated
colorectal cancer. Gut 12: 1625-1629
Bagshawe KD, Harland S 1976 Immunodiagnosis and
monitoring of gonadotrophin producing metastases in the
central nervous system. Cancer 38: 112-118
Bagshawe KD, Dent J, Webb J 1986 Hydatidiform mole in
England and Wales, 1973-1983. Lancet ii: 673-677
Bast RC, Klug TL, St John E et al 1983 A radioimmunoassay
using a monoclonal antibody to monitor the course of
epithelial ovarian cancer. New England Journal of Medicine
308: 883-887
Begent RJ, Rustin GJS 1989 Tumour markers: from
carcinoembryonic antigen to products of hybrid oma
technology. Cancer Surveys 8: 107-121
Bower M, Rustin GJS 1996 Serum tumor markers and their
role in monitoring germ cell cancers of the testis. In:
Vogelzang NJ et al (eds) Comprehensive textbook of
genitourinary oncology. Williams & Wilkins, Baltimore,
pp 968-980
Catalona WJ, Smith DS, Ratliff T L et al 1991 Measurement of
prostate specific antigen in serum as a screening test for
prostate cancer. New England Journal of Medicine
324: 1156-1161
Dorr VJ, Williamson SK, Stephens RL 1993 An evaluation of
prostate-specific antigen as a screening test for prostate
cancer. Archives of Internal Medicine 153: 2529-2537
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Fayers PM, Rustin GJS, Wood R et al 1993 The prognostic
value of serum CA 125 in patients with advanced ovarian
cancer: an analysis of 573 patients by the Medical
Research Council Working Party on Gynaecological
Cancer. International Journal of Gynaecological Cancer
3: 285-292
Froschermaier SE, Pilarsky CP, Wirth MP 1996 Clinical
significance of the determination of noncomplexed prostate-
specific antigen as a marker for prostate carcinoma. Urology
47: 525-528
International Germ Cell Collaborative Group 1997 International
germ cell consensus classification: a prognostic factor-based
staging system for metastatic germ cell cancers. Journal of
Clinical Oncology 15: 594-603
Jacobs I, Prys Da vies A, Bridges J et al 1993 Prevalence for
screening for ovarian cancer in postmenopausal women by
CA 125 measurement and ultrasonography. BMJ 306:
1030-1034
Kallioniemi OP, Oksa H, Aaran R et al 1988 Serum CA 15-3
assay in the diagnosis and follow up of breast cancer. British
Journal of Cancer 58: 213-215
Lennon T, Houghton J, Northover J on behalf of the CRC/NIH
CEA Trial Working Party 1994 Post-operative CEA
monitoring and second-look surgery in colorectal cancer: trial
results. British Journal of Cancer 70: 16
Nagele F, Petru E, Medl M et al 1995 Preoperative CA 125: an
independent prognostic factor in patients with stage 1 epithelial
ovarian cancer. Obstetrics and Gynecology 86: 259-264
Nicolini A, Colombini C, Luciani L et al 1991 Evaluation of
serum CA 15-3 determination with CEA and TPA in the
postoperative follow up of breast cancer patients. British
Journal of Cancer 64: 154-158
Nielsen OS, Munro AJ, Duncan W et al 1990 Is placental
alkaline phosphatase (PLAP) a useful marker for seminoma?
European Journal of Cancer 26: 1049-1054
Petricoin EF, Ardekani AM, Hitt BA et al 2002 Use of proteomic
patterns in serum to identify ovarian cancer. Lancet 359:
572-577
Rustin GJS, Nelstrop AE, McClean P et al 1995 Defining
response of ovarian carcinoma to initial chemotherapy
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311
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The body's response to
surgery
J. P. S. Cochrane, C G. Ha rg reaves
Objectives
• Understand the multisystem nature of the
impact of surgery on the body.
• Recognize the clinical features resulting
from the body's response.
• Appreciate that these responses can be
modified, resulting in improved clinical
outcomes.
INTRODUCTION
^^rStf^Stf^^^^^
The body responds to trauma with local and systemic
reactions that attempt to contain and heal the tissue
damage, and to protect the body while it is injured. The
response is remarkably similar whether the trauma is a
fracture / burn, sepsis or a planned surgical operation, and
the extent of the response is usually proportional to the
severity of the trauma.
The response, with neuroendocrine and inflammatory
cytokine components, increases the metabolic rate,
mobilizes carbohydrate, protein and fat stores, con-
serves salt and water and diverts blood preferentially to
vital organs. It also stimulates important protective
mechanisms such as the immunological and blood clot-
ting systems. However, the overall result is one of
immunosuppression leading to increased vulnerability
to infection.
The interplay between the many inflammatory medi-
ators and cellular responses is very complex and events
at a molecular level are only slowly being unravelled.
New signalling systems and feedback mechanisms con-
tinue to be discovered. These will provide opportunities
for future therapies aimed at blocking the unwanted
aspects of what can be an exaggerated, detrimental
systemic inflammatory response.
Remember also that major surgery has other inevitable
consequences (such as hypothermia and immobility)
which predispose to postoperative morbidity. With
optimal perioperative management, however, their
impact can be minimized. Another common sequel,
anaemia, appears to be well tolerated and physiologically
less significant for most patients than previously
assumed.
Key point
Surgical operation is a controlled form of
trauma in which many aggravating factors can
be manipulated.
INITIATION OF THE RESPONSE
£:^;^^^^^^^
^Vi - S^ -i ^ -\- " -s -* "
Various noxious stimuli produce the response but they
rarely occur alone, and multiple stimuli often produce
greater effects than the sum of single responses. The
response is modified by the severity of the stimulus, the
patient's age, nutritional status, coexisting medical con-
ditions, medication and if the trauma or operation has
affected the function of any particular organ. Recent
trauma or sepsis will also modify the response to a sub-
sequent surgical operation.
Pain. Stimuli from the skin, the musculoskeletal
system, the visceral stretch receptors and, especially,
pulling on the mesentery stimulate the sympathetic
nervous system, adrenocorticotrophic hormone (ACTH)
and arginine vasopressin (AVP).
Tissue injury. Tissue disruption causes local cytokine
release with capillary endothelial damage and leak. This
in turn leads to the migration of inflammatory cells,
amplifying the release of mediators, which can develop
into a systemic inflammatory response. Another mech-
anism of tissue injury is ischaemia followed by reperfu-
sion, leading to production of oxygen free radicals
(reactive oxygen species, ROS).
infection. This is often the underlying reason for
presentation in surgical patients, especially emergencies,
and so the effects of sepsis are often present. Endotoxin
313
31 j
POSTOPERATIVE
from the cell walls of Gram-negative bacteria is the most
powerful stimulus for release of one of the cytokines,
tumour necrosis factor (TNF), from macrophages.
Infection can also enter the circulation from the bowel if
the mucosal barrier is impaired.
Hypovolemia. Most injuries lead to hypovolemia,
either from haemorrhage, plasma loss in burns or third-
space losses. This stimulates baroreceptors, releasing
vasopressin (AVP), catecholamines, renin-angiotensin
and aldosterone, and leads to impaired excretion of
sodium and water, manifesting clinically as oliguria.
Hypoperfusion, especially in the presence of hypo-
tension, can also initiate endothelial damage and progress
to organ dysfunction. Recent evidence suggests that
maintaining optimal circulating volume throughout the
perioperative period can avoid these consequences and
reduce mortality after major surgery.
Starvation. If starvation accompanies trauma it
causes the body to use muscle protein as a source of
energy, leading to muscle wasting and weakness, which
slows recovery. Failure to provide nutritional support can
also impair the immune response, resulting in poorer
healing and more postoperative infections, especially in
those malnourished prior to surgery.
Hypoxia, hypercarbia or pH changes. Chemo-
receptors in the carotid and aortic bodies react to these
changes and stimulate the sympathetic nervous systems,
ACTH and AVR
Energy substrates. Hypoglycaemia stimulates
ACTH, growth hormone, 3 -en dorphin, AVP and cate-
cholamines. This catabolic state also favours muscle
breakdown. Certain amino acids also have particular
effects.
Fear, anxiety and emotion. These stimulate the
sympathetic nervous system, AVP and ACTH.
Temperature. Hypothermia, which is difficult to
avoid in lengthy major surgery, stimulates the hypotha-
lamus and leads to increased secretion of AVP, ACTH,
growth hormone, thyroxine and catecholamines. Studies
have shown improved recovery times with fewer infec-
tions when normothermia is maintained intraoperatively.
SYSTEMS CONTROLLING THE
RJESPOJNSJE__^
The response to surgery is modulated both by the neuro-
endocrine system and the inflammatory mediators, and
the cells controlling their release. The effects are closely
intertwined, with locally produced cytokines having
systemic effects proportional to the extent and severity
of tissue injury. There are multiple feedback loops
which prevent excessive activation of the inflammatory
cascades.
Sympathetic nervous system. The immediate fight
and flight reaction may help the injured person avoid
further injury, but it has short-lasting effects on
metabolism. Activation of the sympathetic pathways also
stimulates the adrenal glands.
Endocrine response. This includes not only the
hypothalamic— pituitary-adrenal (HPA) axis but also
growth hormone, AVP, thyroxine, insulin and glucagon,
causing some metabolic effects, particularly changes
in carbohydrate and fat metabolism. This response
appears to protect not so much against the stress but
more against the body's acute phase response from
overreacting.
Acute phase response. The wound becomes a
'cytokine organ' whose metabolism and local healing
responses are controlled by cytokines and other medi-
ators that are produced locally and also released from
activated inflammatory cells, including neutrophils and
monocytes. In severe trauma, proinflammatory cytokines
produce a systemic "acute phase' response, with profound
changes in protein metabolism, and immunological acti-
vation; these effects are mostly beneficial but in severe
trauma can be lethal.
Vascular endothelial cell response. This affects
vasomotor tone and vessel permeability, so it affects per-
fusion, circulating volume and blood pressure and can
lead to the clinical picture of shock and lung injury. There
are close interactions between the endothelium, acute
phase mediators and leucocytes (neutrophils and mono-
cytes). Endothelial damage also activates the coagulation
cascades and can result in microvascular clotting despite
a generalized abnormal bleeding tendency.
Sympathetic nervous system
The central and peripheral sympathetic systems are stimu-
lated particularly by pain and hypovolemia and this has
direct actions and indirect effects, by releasing adrenaline
(epinephrine) from the adrenal medulla and nor-
adrenaline (norepinephrine) predominately from periph-
eral ganglia. These catecholamines have both a and p
effects on sympathetic receptors that prepare the body
rapidly for fight or flight by cardiovascular, visceral and
metabolic actions. These effects begin when the operation
starts and continue for several days into the postoperative
period for all but minor procedures.
Cardiovascular effects
Blood is redistributed from the viscera and skin (ct effects)
to the heart, brain and skeletal muscles (|3 2 effects),
and there is an increase in heart rate and contractility
(Pt effects).
314
THE BODY'S RESPONSE TO SURGERY
31
Visceral effects
Non-essential visceral functions such as intestinal mo-
tility are inhibited; resulting in paralytic ileus / and
bladder sphincter tone is increased; other actions are;
bronchodilatation (j3 2 ); mydriasis - dilatation of the pupil
(a,); uterine contraction (c^); and relaxation (f* 2 ); visual
field increases.
Metabolic and hormonal effects
Blood glucose rises due to increased breakdown of liver
and muscle glycogen and by gluconeogenesis (c^), and
indirectly by suppression of insulin secretion (a 2 ) and
stimulation of glucagon secretion (p). Other hormonal
actions are stimulation of growth hormone (a) and renin
(p T ). Lipolysis is stimulated in adipose cells, and keto-
genesis is stimulated in the liver.
Endocrine response
The HPA axis is stimulated mainly by the injury itself, but
probably its most important function is to control the
effects of systemically released cytokines.
ACTH. This is released from the anterior pituitary by
neurological stimuli reaching the hypothalamus, or by
hormones such as AVP, angiotensin II or catecholamines.
The ACTH response to stress is not inhibited by adminis-
tered steroids. ACTH stimulates the adrenal cortex to
release glucocorticoids and also potentiates the action of
catecholamines on cardiac contractility.
Glucocorticoids. These usually have only a 'per-
missive' action (allowing other hormones to function)
but the increased levels after trauma have important
metabolic, cardiovascular and immunological actions
proportional to the severity of the trauma. Cortisol is the
main glucocorticoid and its serum level usually returns to
normal 24 h after uncomplicated major surgery but may
remain elevated for many days in extensive burns or if
infection supervenes. It stimulates the conversion of
protein to glucose (catabolic action); it stimulates the
storage of glucose as glycogen; it is an antagonist of
insulin and this assists gluconeogenesis to increase
plasma glucose (diabetogenic action); it helps to maintain
blood volume by decreasing the permeability of the vas-
cular endothelium and enhancing vasoconstriction by cat-
echolamines and suppressing synthesis of prostaglandins
and leucotrienes (anti-inflammatory action); it also
inhibits secretion of interleukin 1 (IL-1) and IL-2 antibody
production and mobilization of lymphocytes (immuno-
suppressant action).
The normal glucocorticoid response can be reduced or
absent (due to previous long-term administration of
steroids, adrenalectomy or adrenal infarction). This
presents with hypoglycaemia, hyponatremia and refrac-
tory hypotension.
Key point
• Adrenal failure is often fatal if you fail to
recognize it at an early stage; it requires
immediate steroid replacement.
Aldosterone. The inevitable release of ACTH after
trauma stimulates a short-term release of aldosterone
from the adrenal cortex, but the rise may be prolonged if
other stimuli such as hypovolaemia or vasomotor
changes (which activate the renin-angiotensin system in
the kidney) occur. A rise in plasma potassium concentra-
tion can also stimulate aldosterone release. Aldosterone
causes increased reabsorption of sodium and potassium
secretion in the distal convoluted tubules and collecting
ducts, and hence a reduced urine volume.
Arginine vasopressin (AVP). Also referred to as
antidiuretic hormone (ADH), this is released from the
posterior pituitary by pain, a rise in plasma osmolality
(via osmoreceptors in the hypothalamus), hypovolaemia
(via baroreceptors and left atrial stretch receptors),
anaesthetic agents or a rise in plasma glucose. Its actions
on the distal tubules and collecting ducts in the kidney
lead to increased reabsorption of solute-free water; it
causes peripheral vasoconstriction, especially in the
splanchnic bed, and it stimulates hepatic glycogenolysis
and gluconeogenesis. Its secretion increases for about
24 h after operation, and during this time the kidney
cannot excrete 'free 7 water (water that is not solute led),
so the urine osmolality remains higher than plasma.
After head injury, burns or prolonged hypoxia there may
be continued secretion of AVP, resulting in oliguria and
hyponatraemia.
Insulin. In the ebb phase after injury, plasma insulin
concentration falls because catecholamines and Cortisol
make the p-islet cells of the pancreas less sensitive to
glucose. Glucagon also inhibits insulin release and Corti-
sol reduces the peripheral action of insulin; less carbohy-
drate is transported into cells and blood sugar rises. In the
flow phase, plasma insulin rises but blood sugar remains
elevated because various intracellular changes make the
tissues resistant to insulin.
Glucagon. Secretion of glucagon from the a-islet cells
of the pancreas increases after injury and this plays a small
part in increasing blood sugar by stimulating hepatic
glycogenolysis (Greek lyein = to loosen; hydrolysis of
glycogen), and gluconeogenesis (Greek glykos - sweet +
neos = new + genesis - origin; the formation of glucose
from non-carbohydrate substances). It also stimulates
315
31
POSTOPERATIVE
hepatic ketogenesis and lipolysis in adipose tissue.
Cortisol prolongs its actions.
Thyroxine. Total T 4 (but not usually free T 4 ) and total
and free T 3 (tri-iodothyronine, the more active hormone)
decrease after injury because Cortisol impairs conversion
of T 4 to T 3 .
Growth hormone. Growth hormone is released
from the anterior pituitary as a result of neurological
stimulation of the hypothalamus or by a rise in circulat-
ing levels of catecholamine s, ACTH, AVP, thyroxine or
glucagon. Its plasma levels increase after trauma, hypo-
volemia, hypoglycaemia or a decrease in plasma fatty
acids or increase in serum arginine. Its main effects are to
promote protein synthesis and enhance breakdown of
lipid and carbohydrate stores. It increases plasma fatty
acids and ketone bodies through direct stimulation of
lipolysis and potentiation of catecholamine effects on
adipose tissue and by stimulation of hepatic ketogenesis.
It is also associated with a fall in insulin levels that allows
plasma glucose to rise.
Acute-phase response
Local effects
Noxious stimuli such as infection, trauma, toxins, haem-
orrhage or malignancy attract granulocytes and mono-
nuclear cells to the site of injury, and these cells, together
with local fibroblasts and endothelial cells, release
cytokines. Cytokines (Greek kytos = hollow, cell + kineein =
to move) are peptides produced by a variety of cells
(unlike true hormones) and produce mainly paracrine
(direct cell-to-cell) effects. Interleukins (IL) 1, 2 and 6, TNF
and the interferons are the main cytokines released early.
Their actions help to contain tissue damage by contribut-
ing to the inflammatory reaction through vasodilatation,
increased permeability of vessels, migration of neutro-
phils and monocytes to the wound, activation of the coag-
ulation and complement cascades, and proliferation of
endothelial cells and fibroblasts.
Systemic effects
If cytokine production is large enough, systemic (Greek
syn = together + histanai = to set; affecting the body as a
whole) effects occur, such as fever, malaise, headache,
myalgia (Greek mys - muscle + algos = pain) as well as
vasodilatation. They may also produce a leucocytosis,
activation of immune function, release of ACTH and glu-
cocorticoids, activation of clotting cascades, an increase in
erythrocyte sedimentation rate (ESR), a decrease in circu-
lating levels of zinc and iron (inhibiting the growth of
microorganisms requiring iron). They also affect the
serum levels of acute phase reactants (APRs) which are
host-defence proteins synthesized in the liver; most
increase (such as C-reactive protein, fibrinogen, comple-
ment C3, a-antichymotrypsin, caeruloplasmin and
haptoglobin), but the levels of albumin and transferrin
decrease.
• IL-6 is the main mediator of this altered hepatic protein
synthesis.
• TNF - tumour necrosis factor (cachectin) released pri-
marily from macrophages by bacterial endotoxin,
causes anorexia, tachypnoea, fever and tachycardia,
with proliferation of fibroblasts and widespread effects
on neutrophils; it stimulates production of other
cytokines, ACTH, APRs and amino acids from skeletal
muscle, hepatic amino acid uptake, and elevation of
plasma triglycerides and free fatty acids. High concen-
trations cause multiple organ dysfunction syndrome
(MODS).
• IL-2 enhances immune function by T-lymphocyte pro-
liferation and by enhancing the activity of natural killer
cells.
• IL-1 in low dosage causes fever, neutrophilia, low
serum zinc levels, increased APR synthesis, anorexia,
malaise, release of ACTH, glucocorticoid and insulin,
and, in high dose, the features of MODS.
• Interferons, such as ^-interferon are glycoproteins pro-
duced by T lymphocytes which activate macrophages,
enhancing both antigen presenting and processing as
well as cytocidal activity; 7-interferon is synergistic
with TNF, inhibits viral replication, and inhibits
prostaglandin release.
• Prostaglandins are important components of the inflam-
matory response. They can be produced by all nucle-
ated cells except lymphocytes; they increase vascular
permeability and cause vasodilatation and leucocyte
migration.
• Leucotrienes are 1000 times as effective as histamine
at increasing postcapillary leakage and they cause
increased leucocyte adhesion, vasoconstriction and
bronchoconstriction.
• Kallikreins and kinins. Bradykinin release is stimulated
by hypoxia and it is a potent vasodilator that increases
capillary permeability, producing oedema, pain and
bronchoconstriction and affecting glucose metabolism.
• Heat shock proteins (HSPs). These are produced by vir-
tually all cells in response to many stresses (not just
heat), mainly via the stimulus of the HPA axis, and they
are also elevated in certain tissues in chronic diseases.
The ability to produce them declines with age and they
appear to protect cells from the deleterious effects of
stress and to inhibit synthesis of APRs.
• 5-Hydwxytryptamine (5HT). This is a neurotransmitter
produced from tryptophan and found in enterochro-
maffin cells of the intestine and platelets. It is released
316
THE BODY'S RESPONSE TO SURGERY
31
when tissue is injured and it causes vasoconstriction
and bronchoconstriction, increases platelet aggregation
and increases heart rate and contractility.
• Histamine. Histamine is released from mast cells,
platelets, neurons, and the epidermis by trauma, sepsis
and hypotension. Its main action is to cause local
vasodilatation and increased vascular permeability, so
large concentrations may lead to hypotension. It acts on
Hj cell surface receptors to increase histamine precursor
uptake and cause bronchoconstriction, and increased
intestinal motility and cardiac contractility; it also acts
on H 2 receptors that inhibit histamine release and
produce changes in gastric secretion, heart rate and
immunological function.
* Endogenous opioids. Endogenous opioids such as
[J-endorphin increase after trauma and produce
analgesia, a rise in blood sugar, a lowering of blood
pressure and effects on immune function.
Interactions between APRs and the
endocrine response
IL-l and IL-6 can activate the HPA axis by increasing
ACTH secretion and also directly stimulating glucocorti-
coid release from the adrenal gland. Glucocorticoids ini-
tially help cytokines to regulate APRs, but if glucocorticoid
levels remain elevated they inhibit cytokine production.
The vascular endothelial response
The scattered 'endothelial organ' weighs about 1.5 kg.
After tissue injury it is activated locally, resulting in
the appearance of glycoprotein selectins (adhesion
molecules) on the endothelial cell surface along with
intercellular adhesion molecules (ICAMs). Neutrophils
recognize these surface molecules, begin to stick and then
migrate out into the interstitium, with a concurrent
increase in endothelial permeability, particularly in the
postcapillary venules.
Nitric oxide is a powerful vasodilator produced mainly
by endothelial cells but also by macrophages, neutrophils,
Kupffer cells and renal cells. It is inactivated by
haemoglobin and opposed by endothelins. Its other
action is to increase production of APRs.
Endothelins are a family of potent vasoconstricting pep-
tides with mainly paracrine actions. They are released by
thrombin, catecholamines, hypoxia, cytokines and endo-
toxins. They counteract nitric oxide and prostacyclins to
maintain vasomotor tone.
Platelet-activating factor (PAF) is released from endo-
thelial cells by the action of TNF, IL-l, arginine vaso-
pressin (AVP or antidiuretic hormone) and angiotensin II.
When platelets come into contact with PAF they release
thromboxane which causes platelet aggregation and
vasoconstriction. PAF also reduces the permeability of
endothelial cells to albumin and may also affect glucose
metabolism.
Prostaglandins cause vasodilatation and reduce platelet
aggregation. Other arachidonic acid derivatives include
thromboxanes, which are also produced by cyclo-
oxygenase. An inducible form of this enzyme (COX-2) is
activated.
Atrial natriuretic peptides (ANPs) are potent inhibitors of
aldosterone secretion and are released by atrial tissue
(which is specialized endothelium) in response to changes
in chamber distension. They can also be released by the
CNS. It is not yet clear what role they play in the response
to injury.
Intracellular signalling processes and
regulation of the acute stress response
• Gene transcription: stimulation of cells by cytokines and
other products of inflammatory damage, such as
oxygen free radicals, appears to be coupled to sig-
nalling systems that lead to upregulation of the genes
coding for enzymes and cytokines by increasing RNA
transcription. These inducible enzymes then greatly
increase the production of mediators, sustaining the
inflammatory response. Families of transcription factor
proteins known as inhibitor of kappa B kinase /nuclear
factor kappa B (IKK/NF kappa B) seem to be one of the
central components. They appear to control inducible
nitric oxide synthetase (iNOS) and COX-2, as well as
transcription of the IL-6 and TNFa genes.
• Apoptosis (Greek apo - from + piptein = to fall) is the pro-
grammed death of cells which ensures turnover of
short-lived immune cells. It increases after trauma and
also in sepsis, contributing to immunosuppression by
loss of lymphocytes. Apoptosis also appears to be
under the control of complex intracellular signalling
processes.
CLINICALLY APPARENT SYSTEMIC
EFFECTS OF THE RESPONSE
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Body temperature
Following correction of any intraoperative hypothermia
in the immediate postoperative period, there is often a
1-2°C increase in body temperature because the increased
metabolic rate is accompanied by an upward shift in the
thermoregulatory set point of the hypothalamus. Pyrexia
can be difficult to interpret when infection is suspected or
already present. Some of the effects of fever are detri-
mental, but more are beneficial.
317
31
POSTOPERATIVE
Cardiovascular system
A mild tachycardia is commonly seen, along with peri-
pheral vasodilatation. Cardiac output can rise at least
threefold provided intravascular volume is maintained.
Hypovolaemia due to blood and other fluid losses can
exaggerate the tachycardia and lead to hypotension
and peripheral shutdown, indicating inadequate fluid
replacement. The acute phase response of vasomotor
changes and increased vessel permeability causes fluid
loss into the 'third space', the name for a sequestered part
of the extracellular fluid (ECF) which includes oedema
fluid in the peripheral tissues, wound, peritoneal cavity
or the lungs.
Pulmonary effects
Reduction in forced vital capacity and functional residual
capacity lead to shunting of blood and a decreasing Pa0 2
after major surgery. Hypoxaemia is more pronounced and
prolonged after upper abdominal surgery. The changes
are significantly lessened by laparoscopic compared with
open operation and by good quality pain relief. If secre-
tions obstruct bronchioles, basal collapse can progress to
pneumonia after any operation, particularly in immobile
patients recumbent in bed. Tachypnoea leads to a respir-
atory alkalosis and a fall in Paco 2 .
Acute lung injury is the inflammatory reaction due to
pulmonary capillary endothelial damage and fluid leak into
the alveoli and interstitium. This 'non-cardiogenic pul-
monary oedema' leads to hypoxaemia due to ventilation-
perfusion inequalities (i.e. shunt). This can be a component
of systemic inflammation or directly triggered by specific
factors, e.g. blood transfusion. There is a spectrum of sever-
ity, with the most extensive, acute respiratory distress syn-
drome (ARDS), leading to severe respiratory failure and
widespread infiltrates on X-ray. The changes improve with
resolution of the underlying inflammation but overall
survival in ARDS is at best 60-70%.
Effects on the gastrointestinal tract
• Adynamic ileus. There is inhibition of gastric emptying
and reduced colonic motility from increased sympa-
thetic tone and the effects of opioid analgesics. Small
intestine peristalsis is minimally affected. Usually, ady-
namic (Greek a - not + dyasthai = to be able) ileus is
transient and enteral intake can restart early in the post-
operative period.
• Gut mucosal barrier. Increased permeability is thought
to allow translocation of bacterial toxins into the circu-
lation, leading to escalation of the inflammatory
response. It is still unclear whether this is a primary
cause or secondary response.
Biochemical and fluid balance disturbance
1. Salt and water retention. This results from the miner-
alocorticoid effects of both aldosterone and Cortisol. This
is compounded by raised levels of AVP, further hindering
excretion of free water and resulting in lower volumes of
high osmolality urine. Any reduction in renal perfusion
from hypotension secondary to hypovolaemia or from the
administration of non-steroidal anti-inflammatory drugs
also worsens oliguria and can lead to acute renal failure.
Although the maintenance of intravascular volume by
administered intravenous fluids offsets these effects,
weight gain of several kilograms from retained fluid can
be seen. A major but uncomplicated surgical operation
with adequate fluid replacement is, therefore, usually fol-
lowed by 24 h of impaired free water clearance and about
5 days of impaired sodium excretion. This can be more
pronounced in the presence of systemic inflammation
where "third space' losses are greater (see Cardiovascular
system above). The diuresis that occurs when this third
space fluid mobilizes is a welcome sign of recovery.
2. Hyponatraemia. This often accompanies the above
changes, partly a dilutional effect from retained water
(due to AVP), and partly because sodium drifts into cells
(impaired sodium pump); it does not indicate sodium
deficiency, as it occurs at a time when the total body
sodium is elevated. Serum potassium may rise due to cell
death, liberation of potassium by protein catabolism and
from impaired potassium excretion. However, it is more
usual to see increased urine potassium excretion, which
can lead to an overall potassium deficit.
3. Acid-base abnormalities. The commonest change is a
metabolic alkalosis because intense reabsorption of
sodium in the distal tubules of the kidney is accompanied
by excretion of potassium and hydrogen ions; this impairs
oxygen delivery to the tissues because it affects the
oxygen-haemoglobin dissociation curve. In more severe
injuries a metabolic acidosis supervenes due to poor
tissue perfusion and anaerobic metabolism with accumu-
lation of lactic acid. Acidosis may decrease myocardial
contractility and produce arrhythmias, as well as decreas-
ing the effect of catecholamines on the myocardium and
peripheral vessels. Respiratory compensation with
tachypnoea and reduced PaC0 2 then occurs.
Metabolism after injury
1. There is an initial 'ebb' phase (Fig. 31.1) of reduced
energy expenditure after injury for up to 24 h. This
changes to a catabolic 'flow' phase with increased
metabolism, negative nitrogen balance, hyperglycaemia,
increased heat production, increased oxygen consump-
tion and lean bodyweight loss. The increase in metabolic
rate ranges from about 10% in elective surgical operations
318
THE BODY'S RESPONSE TO SURGERY
31
EBB PHASE
FLOW PHASE
Catabolic Anabolic
Injury
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o
E
1
L 1
1 1 1
1 1 1 1
Days
Fig. 31.1 Change in metabolic rate relative to preoperative level.
to 50% in multiple trauma and 200% in major burns. This
may last for days or weeks, depending on the severity of
the injury, previous health of the individual and medical
intervention; it is less marked at the extremes of age or
in previously malnourished individuals. Once started,
it cannot be stopped rapidly by controlling infection,
correcting hypovolaemia or blocking pain. If recovery
occurs, it is followed by an anabolic phase in which
weight gain is accompanied by restoration of protein and
fat stores. This process is slow and prolonged.
2. Lipids are the principal source of energy following
trauma. Lipolysis is produced mainly by catecholamines
and increased sympathetic nervous system activity and
also by lower plasma insulin, a rise in ACTH, Cortisol,
glucagon, growth hormone and, probably, cytokines.
Ketones are released into the circulation and are oxidized
by all tissue except the blood cells and the CNS. Free fatty
acids provide energy for all tissues and for hepatic
gluconeogenesis.
3. Carbohydrates. Hyperglycaemia occurs immedi-
ately after injury because glucose is mobilized from
stored glycogen in the liver by catecholamines and glu-
cocorticoids, and because insulin resistance of peripheral
tissues impairs their uptake of glucose (the 'diabetes of
injury'). Glucose provides energy for obligate tissue such
as the CNS, leucocytes in the wound and red cells (cells
not requiring insulin for glucose transport). In major
injuries the inflammatory cell infiltrate can account for
70% of glucose uptake.
4. Body glycogen stores can only maintain blood
glucose for about 24 h. Subsequently it is maintained by
gluconeogenesis, stimulated by corticosteroids and
glucagon, and this is helped by the initially suppressed
insulin levels encouraging the release of amino acids from
muscle. Even when insulin levels rise, they do not sup-
press this increased hepatic gluconeogenesis because it is
required for clearance of lactate and amino acids that are
not used for protein synthesis.
5. Amino acids, protein and skeletal muscle. Shortly
after injury skeletal muscle protein breakdown supplies
the three- to fourfold increased demand for amino acids
(unless there is an exogenous protein source); this
reaches a peak after 1 week and may continue for several
weeks. The nitrogen loss is proportional to the severity
of the trauma, the extent of sepsis and the muscle bulk
(so it is greatest in fit young males). The mobilized
amino acids are used for gluconeogenesis, oxidation in
the liver and other tissues, and synthesis of APRs.
Glutamine is a major energy source for the gastroin-
testinal tract, for lymphocytes and for fibroblasts during
catabolism, and may become an 'essential' amino acid at
this time. The negative nitrogen balance and skeletal
muscle breakdown can be offset but not reversed by
nutritional support. The catabolic phase is followed by
an anabolic phase produced by growth hormone, andro-
gens and 17-keto steroids.
6. Other reasons for skeletal muscle loss include rhab-
domyolysis in trauma and limb ischaemia, disuse
319
31
POSTOPERATIVE
atrophy from prolonged immobility and denervation
from the polyneuropathy of critical illness. These factors
can all produce weakness which requires prolonged
rehabilitation.
Haematological changes
Serum albumin falls after trauma because production by
the liver decreases, and loss into damaged tissue increases
due to the action of cytokines and prostaglandins on
vessel permeability. The accompanying shift of fluid out
of the intravascular compartment is a contributing cause
of dysfunction in various organs.
The coagulation cascade and platelet activation leads to
a state of hypercoagulability that may be beneficial at the
site of injury but increases the risk of venous thrombi
forming. If coagulation is triggered away from the
wound, for example by sepsis or hypoxic damage to
endothelial cells, then disseminated intravascular coagu-
lation can result.
Leucocytosis occurs; it appears to be due mainly to
cytokine-stimulated release of neutrophils from bone
marrow.
Immunological responses
Trauma leads to impairment of the immune system, with
defects in cell-mediated immunity, antigen presentation,
neutrophil and macrophage function complement acti-
vation and bacterial opsonization. This occurs at a time
when the initial injury has usually breached mechanical
defences, when catabolism impairs the mucosal barrier in
the bowel and when many factors contribute to produce
pneumonia and other infections.
Wound healing
The systemic responses give 'biological priority' to
wound healing, but a wound still heals more slowly if
there are other major injuries.
Systemic inflammatory response syndrome
(SIRS)
This is defined by set criteria of fever, tachycardia,
tachypnoea and leucocytosis. This cluster of clinical fea-
tures is seen in a range of conditions where inflammation
is present. These include those where infection is the
cause, e.g. appendicitis, as well as those which can mimic
sepsis but where infection is absent, e.g. pancreatitis or
blunt trauma. SIRS features are often present in the post-
operative surgical patient and reflect the extent of activa-
tion of the inflammatory cascades.
Multiple organ dysfunction syndrome
In some patients the inflammatory response may become
so amplified that shock supervenes and support of failing
organs is required. There may then be an irreversible pro-
gression to multiple organ failure and death. In this situ-
ation, inflammatory damage appears to be excessive and
uncontrolled and not amenable to treatment. The clinical
picture is the same as that in septic shock, even though
infection is absent.
There is some evidence that an initial inflammatory
stimulus, such as infection, trauma or surgery, 'primes'
the cellular control of inflammation and that a second
stimulus, e.g. sepsis, triggers an overwhelming response
(two-hit theory). This may be linked to intracellular pro-
cesses such as apoptosis.
WAYS OF AFFECTING THE RESPONSE
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Although the local response to trauma is beneficial, the
systemic response becomes less helpful as the degree of
trauma increases, and in a hospital setting it is an advan-
tage to suppress and control the response. In trauma and
emergency surgery, pain, bleeding with hypovolemia,
hypoxia and anxiety have often been present for some
hours before operation starts, whereas in elective surgery
it is usually possible to control these stimuli and thereby
reduce the systemic response.
Recent studies demonstrate that preoperative opti-
mization of the circulation by the use of fluid loading and
inotropes to increase cardiac output and oxygen delivery
can improve the outcome of major surgery.
Beta blockers given through the perioperative period
confer cardiac protection in vulnerable patients. There
appears to be a prolonged survival advantage well
beyond the duration of administration.
Reduce stimuli causing the response
Less trauma
- care in handling tissues
- minimally invasive surgery.
Control of infection
- remove source of toxins
- debride wounds and drain pus
- antibiotics (selective gut decontamination
with antibiotic combinations is still being
investigated).
Nutritional support
- enteral feeding to maintain the gut mucosal
barrier integrity
320
THE BODY'S RESPONSE TO SURGERY
31
- 'immunonutrition' with added glutamine,
arginine and omega-3 fatty acids may be of
some additional benefit when delivered
early.
• Control of pain
- analgesics, local and regional blockade
(given, if feasible, before the noxious stimuli
occur).
• Correct hypovolaemia
- prompt replacement of fluids and
electrolytes lost
- transfusion for haemorrhage only if anaemic
with Hb < 80 g I 1 in fit patients
- colloid for plasma losses.
• Correct metabolic alkalosis or metabolic
acidosis.
• Correct hypoxaemia
- attention to airway, breathing and
administration of oxygen.
• Remove fear and stress
- give explanations
- administer analgesics or anxiolytics.
Metabolic manipulation
Protein administration to malnourished patients improves
their immune function but has no immediate benefit on
wound healing. Enteral feeding has particular benefits over
the parenteral route because it helps to maintain the gut
mucosal defence barrier. Increased intake of arginine
(which improves weight gain, nitrogen balance, wound
healing and immune function) and glutamine (which
improves nitrogen balance and prevents the redistribution
of body water) can be helpful.
Drug administration
Ways of manipulating the body's response to trauma are
being sought but are still experimental. Many agents are
only effective if given before the injury or sepsis occur,
and it is difficult to block deleterious responses and still
preserve beneficial ones.
Steroids, antiendotoxin antibodies, anti-TNF anti-
bodies, IL-1 receptor antagonists and specific PAF recep-
tor antagonists have increased survival in septic animals
but have been disappointingly ineffective in humans. A
recent study involving activated protein C in septic shock
appears more promising; however, as bleeding tendency
is increased it may not be suitable for septic patients
undergoing surgery. Other agents that have been used
are adrenergic blockers (decrease the metabolic rate),
aspirin (attenuates cytokine actions), growth hormone
and anabolic steroids (stimulate protein synthesis),
mannitol (hydroxyl radical scavenger), propranolol
(improves postoperative nitrogen balance), allopurinol
(inhibits free radical formation) and atrial natriuretic
factor (natriuretic).
Summary
• Do you appreciate that multiple factors in
the underlying disease, comorbidity, and
the effects of the trauma of a surgical
operation cause widespread effects in the
body?
• Are you aware of the wide range of
clinically detectable effects?
• Are you aware of your potential to reduce
the stimuli, including trauma, in order to
alleviate the effects of surgery?
Further reading
Beal AL, Cerra FB 1994 Multiple organ failure syndrome in the
1 990s. JAMA 271 (3): 226-233
Davies MG, Hagen PO 1997 Systemic inflammatory response
syndrome. British Journal of Surgery 84: 920-935
Hill AG, Hill GL 1998 Metabolic response to severe injury.
British Journal of Surgery 85: 884-890
Holte K, Kehlet H 2000 Post-operative ileus: a preventable
event. British Journal of Surgery 87: 1480 -1493
Huljamae H 1993 The pathophysiology of shock. Acta
Anaesthesiologica Scandinavica 37(suppl. 98): 3-6
Le Quesne LP, Cochrane JPS, Fieldman NR 1985 Fluid and
electrolyte disturbances after trauma: the role of
adrenocortical and pituitary hormones. British Medical
Bulletin 41(3): 212-217
Mainous MR, Block EFJ, Deitch EA 1994 Nutritional support of
the gut: how and why. New Horizons 2(2): 193-201
Molloy RG et al 1 993 Cytokines, sepsis and
immunomodulation. British Journal of Surgery 80(3): 289-297
Schmidt H, Martindale R 2001 The gastrointestinal tract in
critical illness. Current Opinion in Clinical Nutrition and
Metabolic Care 4(6): 547-551
Senftleben U, Karin M 2002 The IKK/NF-kB pathway. Critical
Care Medicine 30(1) (SuppL): S18-S26
Treasure T, Bennett D 1999 Reducing the risk of major elective
surgery. BMJ 318: 1087-1088
Woolf PD 1992 Hormonal responses to trauma. Critical Care
Medicine 2(2): 216-226
321
Wound healing
5. R. Lakhani, A. Dogan
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Objectives
Understand the stages of wound healing.
Understand the mechanism of wound
contracture, its usefulness and its
complications.
Recognize the factors that affect wound
healing.
Be familiar with complications that may
arise as a result of healing and repair.
INTRODUCTION
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The processes involved in wound healing are some of the
most fascinating biological phenomena you are likely to
encounter. In this chapter we shall examine the processes
involved/ and hopefully appreciate the complex interplay
that allows the body to restore the integrity of its tissues.
As a surgeon, you rely on the normal functioning of these
processes on a daily basis.
Three fundamental things must happen if wound
healing is to occur. First, the circulatory system must be
able to control the bleeding (establish haemostasis; Greek
haima - blood + statikos = causing to stand). Second, the
inflammatory response must be effective and provide a
defence against microbial infection as well as provide the
necessary chemical environment for attracting and stimu-
lating the cells needed for repair. Finally, the process of
repair requires many different cell types to proliferate and
to synthesize proteins necessary for restoring integrity
and strength to the tissue. Although these three basic pro-
cesses must occur in the healing of all wounds, you will
be aware that not all your patients behave in exactly the
same way. The process described above may be modified
considerably by the size of the wound, the nutritional
status of the patient, and hence his or her immune com-
petence, the state of the vasculature at the site of injury,
and the metabolic demands of the tissue that has been
injured. It is not any one thing, but rather a complex and
dynamic interplay between many factors within an intri-
cate network, that determines the final outcome.
Wound healing requires:
• Haemostasis
• Inflammation
• Cell proliferation and repair.
THE PROCESS OF WOUND HEALING
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The biological objectives of wound healing are twofold:
• To restore the integrity of epithelial surfaces if they have
been lost, and hence protect the underlying tissues
against infections and insults from the environment
• To restore the tensile strength of the subepithelial tissue.
Healing by 'primary' and 'secondary' intention
Although the basic mechanisms involved in wound
healing are the same, by convention the healing of cleanly
incised wounds, where the edges are in close apposition,
is considered separately from those in which there is
extensive loss of epithelium, a large subepithelial tissue
defect that has to be filled in by scar tissue and where the
edges cannot be brought together with sutures. These two
circumstances are described as 'healing by primary inten-
tion" or 'healing by secondary intention'. These terms
first appeared in a surgical treatise published in 1543,
although Thomson (1813) in Lectures on Inflammation,
gives the credit for introducing these terms to Galen.
THE HEALING OF AN INCISED
WOUND: 'HEALING BY PRIMARY
INTENTION'
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Incision involves the division of:
• Epidermis
• Dermal connective tissue fibres and matrix
322
WOUND HEALING
32
• Subcutaneous tissue
• Blood vessels.
The very first thing that must be established is haemosta-
sis. Severing of blood vessels obviously leads to haemor-
rhage, with the resulting accumulation of blood within the
tissue defect. Injury to blood vessels leads to arteriolar con-
traction, which helps to reduce the bleeding. Platelets and
plasma proteins, particularly fi brinogen and fibronectin, also
accumulate. Clotting occurs by both the 'intrinsic' and
'extrinsic' pathways. The former is due to exposure of the
collagen and the latter due to release of 'tissue factors 7
from damaged cells. The platelet plug becomes converted
to a clot consisting of polymerized fibrin, which is stabi-
lized by fibronectin binding to it by means of a gluta-
minase bridge. 'Fibronectin' (Latin nectere = to bind, tie) is
the term used for a set of large, extracellular matrix glyco-
proteins, and the gel formed by fibrin and fibronectin acts
in the early stages of healing as a 'glue' which helps to
keep the severed edges of the tissue apposed. Thrombin,
which is involved in the generation of fibrin, also attracts
macrophages and induces fibroblasts to divide. So here we
have a molecule that not only has a role in haemostasis but
also begins the process of repair. Platelet-derived growth
factor (PDGF) released from degranulating platelets has a
similar effect on fibroblasts. Transforming growth factor p
and monocyte chemoattractant protein 1 are also respon-
sible for pulling macrophages into the area, which in turn
can release PDGF.
At the same time as haemostasis is being established,
the process of inflammation is also kicking into action.
This involves dilatation of capillaries and the formation of
a fluid and cellular exudate. The polymorph leucocytes
will attack and remove any bacteria and also scavenge
any tissue debris from the cell death. The exudate is
responsible for the tissue swelling that occurs. This not
only splints and immobilizes the affected area but also the
network of fibrin within the exudate forms an infrastruc-
ture that helps to localize the microorganisms, hence
allowing the polymorphs easy access to them. As men-
tioned above, one of the biological objectives is to protect
the tissues from infectious and environmental hazards
and the exudate performs exactly this task by clotting and
forming a scab over the wound.
The next important stage is one of cell proliferation and
migration. Purely for convenience, the events are divided
into those involving the epidermis and those involving
the dermis.
Epidermal events
Within a few hours of wounding, a single layer of epi-
dermal cells start to migrate from the wound edges to
form a delicate covering over the raw area exposed by the
loss of epidermis. This is a fascinating process. The epi-
dermal cells have to undergo a phenotypic change that
will allow them to detach from each other, from the base-
ment membrane and hence dermal cells, and acquire
properties that help them to move into the wound space.
This is achieved by loss of intracellular tonofilaments, loss
of desmosomes and formation of actin filaments, which
allows cell movement. The cells express a family of inte-
grin receptors that allows them to interact with extracellu-
lar proteins, in particular fibronectin and vitronectin.
Epidermal cell migration across the area of epithelial loss
depends on interaction between the keratinocytes at or
near the wound edges, fibrin and fibronectin. Fibronectins
are present both within plasma and within tissues.
Originally they were thought to be cell surface proteins
but it is now realized that they constitute part of the extra-
cellular matrix and exert much of their effect by provid-
ing sites which act as ligands for receptors on a wide
variety of cell types. This ligand-receptor binding medi-
ates cell matrix adhesion. Keratinocytes from normal,
unwounded skin do not possess receptors which bind to
fibronectin, being tightly attached to basement mem-
brane, which contains laminin and collagen type IV.
Those derived from wounds, however, express a
fibronectin receptor which is very similar to a fibronectin
receptor expressed on fibroblasts. The cells migrate at a
rate of approximately two cell diameters per hour.
Key point
• Recognize that static, adherent, epithelial cells
have detached themselves and moved, like
amoebae, to cover the wound.
Epidermal cell movement can provide an initial cover-
ing for very small wounds, but in most instances epi-
thelial recovering cannot be accomplished without
proliferation of epidermal cells. The new cells are derived
from the stem cell compartment of the epidermis. From
about 12 h after wounding, there is a marked increase in
mitotic activity in the basal cells about 3-5 cells from the
cut edges. The exact biological mechanisms that lead to
this proliferation are still unclear, although release of
growth factors and expression of growth factor receptors
must play a role. Candidates include epidermal growth
factor, transforming growth factor a and keratinocyte
growth factor. The new epidermal cells grow under the
surface fibrin /fibronectin clot and for a little distance
down the gap between the cut edges to form a small
'spur' of epithelium, which afterwards regresses. If the
wound has been sutured, a similar downgrowth of new
epidermis occurs in relation to the suture tracks and, on
323
32
POSTOPERATIVE
occasion, these may form the basis of keratin-forming
cysts within the dermis - so-called 'implantation dermoid
cysts'. This ability of epidermal cells to grow along tracts
created by sutures or other foreign material is of course
the basis for piercing of tissues for ear-rings, nose-rings,
etc. Once re-epithelialization is complete, basement pro-
teins will reappear and the epithelial cells revert to their
normal non-migratory phenotype.
vascularized gel in which both inflammatory cells and
collagen-producing fibroblasts are present is known as
granulation tissue. The term, coined by the great German
pathologist Rudolf Virchow (1821-1902), is derived from
the observation that the raw surface of a wound shows a
granular appearance rather like that seen on the surface
of a strawberry. Each of these 'granules' contains a loop
of capillaries and hence bleeds easily if traumatized.
Dermal events
After the initial arrival of neutrophils to the site of injury,
there is recruitment of macrophages into the area (1-2 days
after wounding). This is a key event because it is these
cells that orchestrate the complex interplay of chemical
signs that now takes place. The macrophages are involved
in:
• Demolition and removal of any inflammatory exudate
and tissue debris.
• Restoring the tensile strength of the subepithelial con-
nective tissue. This is accomplished by: (1) secretion of
chemoattractants, which recruits cells that synthesize
and secrete collagen and other connective tissue pro-
teins (i.e. fibroblasts); (2) expansion of the existing
small fibroblast population by stimulating the cells to
proliferate; and (3) stimulation of these new fibroblasts
to secrete extracellular connective tissue proteins.
• The ingrowth of new small blood vessels (angiogene-
sis) into the area undergoing repair; this is thought to
be due to the secretion of vascular endothelial growth
factor (3, angiogenin, angiotropin, TNF-et (tumour
necrosis factor), hypoxia and accumulation of lactate
that occurs in anoxic tissues. The angiogenesis
involves: (1) budding of new endothelial cells from
small intact blood vessels at the edges of the wound;
and (2) chemoattraction of these new endothelial cells
into the fibrin /fibronectin gel within the wounded
area.
In a surgical wound, fibroblasts and myofibroblasts
appear in the wound between 2 and 4 days after wound-
ing, and endothelial cells follow about 1 day later. The
infiltration of macrophages and fibroblast proliferation
are followed/ as stated above, by the ingrowth of new
capillary buds, which are derived from intact dermal
vessels at the margins of the wound. Initially these buds
consist of solid ingrowths of endothelial cells, but they
soon acquire a lumen. An essential starting step for the
ingrowth of new vessels is local degradation of the base-
ment membrane of the existing capillary, this local defect
permitting the budding of new endothelial cells. At this
stage newly formed capillaries have little basement
membrane substance and, compared with a normal ca-
pillary, are extremely leaky. This combination of a richly
Mi
Key point
• Granulation tissue formation is common to all
forms of repair.
The ultimate development of tensile strength in a wound
depends on the production of adequate amounts of
collagen and on the final orientation of that collagen.
Collagen is the only protein that contains large amounts
of the amino acids hydroxyproline and hydroxylysine.
Within 24 h of wounding, protein-bound hydroxyproline
appears within the damaged area, and within 2-3 days
some fibrillar material may be seen, although at this time
it lacks the dimensions and the typical 64 nm banding of
polymerized collagen. Within a few weeks, the amount of
collagen in the wounded area is normal, although pre-
operative tensile strength is not regained for some
months. This suggests that replacement and remodelling
of the collagen formed early in wound healing is an
important part of the whole process. The final result is a
scar composed of collagen fibres and very few cells or
vessels. The scar therefore changes from pink to white,
but this may take many months to occur. It will be appar-
ent that abnormal regulation of this process is responsi-
ble for development of keloid scars.
HEALING OF WOUNDS ASSOCIATED
WITH A LARGE TISSUE DEFECT:
'HEALING BY SECONDARY
INTENTION'
1 ■> , ---1. *■ _ ' ^ I =, i _^ ■■"• - ■*•-> _» - i
A large volume of tissue loss can occur in cases of severe
trauma or extensive burns, or, much less frequently, in
relation to certain surgical procedures. Although qualita-
tively there are few differences between healing of an
incised wound and healing of larger wounds, the most
significant problem relates to filling the large defect.
Clearly the formation of granulation tissue, and ulti-
mately of scar tissue, occurs, albeit on a far larger scale.
One feature, however, that helps to speed up the healing
process, and which is not seen in relation to healing of
incised wounds, is wound contraction.
324
WOUND HEALING
32
Wound contraction
Two or three days after the formation of large open
wounds, the area of raw tissue starts to decrease. This is the
expression of a real movement of the wound margins and
is quite independent of the rate at which covering by a new
epithelial layer can take place. In some fur-bearing animals
the raw area may decrease in size by as much as 80% in
2 weeks, and sometimes the degree of contraction may be
so great as virtually to close the wound. The wound con-
traction occurs at a time when relatively little new collagen
is being formed in the dermis and subcutaneous tissue, and
it therefore seems unlikely that shortening of collagen fibres
at the wound margins is responsible for the contraction.
Indeed, inhibition of collagen formation does not interfere
with the process of wound contraction. There appear to be
two mechanisms by which wounds contract. Initially, the
scab formed from coagulated exudate containing fibrin
contracts. Later, contraction is brought about by the action
of cells which appear at the margins of the wound in the
first few days and which, on electron microscopy, show fea-
tures suggesting both fibroblast and smooth muscle differ-
entiation. These cells are called myofibroblasts. The cells
contain actin, but no smooth muscle-type myosin within
their cytoplasm. For a pulling force to be exerted there must
be a connection between the object being pulled and what-
ever is applying the force. In wound contraction the con-
nection is provided by nbronectin molecules which form
bridges between collagen fibres on the one hand and recep-
tors on the myofibroblasts on the other. Thus strips of
granulation tissue from healing wounds can be made to
shorten in vitro by any pharmacological agents that cause
actin fibrils to contract. In vivo, it appears that transform-
ing growth factors pi and [32 may play a role. It has been
postulated that a similar mechanism is responsible for the
contracture of dermal connective tissue seen in such con-
ditions as Dupuytren's contracture.
Key point
• Wound contraction takes place before a
significant amount of collagen has been laid
down or matured, to contribute to it.
Growth factors and cytokines in wound
healing
It is clear from what has been said in the previous sections
that the cellular events in wound healing must depend on
a series of 'instructions' which:
• Facilitate migration of fibroblasts and endothelial cells
• Induce these cells, as well as the epithelial cells, to
proliferate.
These instructions consist of a set of chemical signals
derived from a number of sources. They fall into two
principal types: growth factors and cytokines.
Growth factors
Growth factors are peptides which act via one or more of
three pathways:
• The endocrine pathway, where the growth factors are
synthesized at some considerable distance from their
targets and are delivered via the bloodstream
• The paracrine pathway, where the growth factors are
synthesized and released by cells which are in close
proximity to their targets
• The autocrine pathway, in which the same cells both
synthesize and stimulate their own growth.
The growth factors important in wound healing include
platelet-derived growth factor, epidermal growth factor
and transforming growth factors a and |3. We will con-
sider these briefly
1. Platelet-derived growth factor. Platelet-derived growth
factor is a basic protein which has a molecular weight of
about 30 000. It consists of two peptides (an A chain and a
B chain) which are bound by disulphide bridges. The
name 'platelet-derived growth factor' is somewhat mis-
leading in two senses. First, while it is certainly stored in
the a granules of platelets and released from them when
the platelets are activated, the growth factor is also syn-
thesized and secreted from other cells. These include
endothelial cells, macrophages, arterial smooth muscle
cells and cells from certain tumours. Secondly, PDGF has
a number of functions apart from its undoubted powerful
mitogenic effect. It is chemotactic for the same cells for
which it is a mitogen; it increases intracellular synthesis of
cholesterol; and also increases binding of low density
lipoprotein (LDL) by increasing the number of LDL recep-
tors expressed on the plasma membrane of the target cell.
It increases prostaglandin secretion, initially by making
more of the starting material (arachidonic acid) available,
and later by stimulating the synthesis of cyclooxygenase.
It is able to induce changes in cell shape by a reorganiza-
tion of actin filaments within the cells and it induces
increased synthesis of RNA and protein. It is also a potent
vasoconstrictor. Thus PDGF can carry out both tasks that
were outlined at the beginning of this section. It can attract
mesenchymal cells into the wound (with the exception of
endothelial cells which do not possess the PDGF receptor)
and it acts as a mitogen and stimulator of protein produc-
tion. PDGF and other growth factors bind to receptors
which, after ligand-receptor interaction, act as tyrosine
kinases and hence activate the signal transduction path-
ways for mitogenesis.
325
POSTOPERATIVE
2. Epidermal growth factor and transforming growth
factor a. Epidermal growth factor (EGF) is a 53 amino acid
polypeptide which is cleaved from a larger precursor
protein. It was discovered by the Nobel laureate Cohen in
the course of experiments in which he was engaged in a
search for a nerve growth stimulating factor in the
salivary glands of baby mice, such a factor having been
discovered previously in the salivary glands of snakes.
However, extracts of these glands, when injected into
baby mice, caused their eyes to open prematurely and
their incisor teeth to grow faster, these effects being due
to a stimulation of epidermally derived tissues. The factor
was purified and is now known as epidermal growth factor,
although it stimulates mitogenesis in connective tissue as
well as in epithelial cells. The salivary glands and the
lacrimal glands are storage sites for EGF, which can be
released in saliva and tears. Thus, licking one's wounds
in the literal rather than in the metaphorical sense may be
of definite biological advantage, as may be the irrigation
of the cornea by tears in corneal abrasion or ulceration.
EGF, or a molecule with considerable homology, is also
produced in the Brunner's glands in the duodenum, and
its metabolite, urogastrone, may be measured in the urine.
In rodents, EGF may be found in the plasma but in
humans, blood-borne EGF is concentrated within the a
granules of platelets. Since EGF protein can also be found
in the cytoplasm of megakaryocytes in the bone marrow,
it seems almost certain that platelet EGF is derived from
synthesis within the megakaryocytes rather than by
uptake from the plasma. In experimental wounds the
application of EGF has been found to significantly accel-
erate the rate of epidermal regeneration and it has also
been shown to have a beneficial effect on the dermal com-
ponent. In humans, topical application of EGF accelerates
the healing of donor sites for skin grafts. There is no evi-
dence that EGF is produced by any of the cells taking part
in the healing process, although, as already stated,
platelets store EGF. However, there is another factor,
known as transforming growth factor a (TGF-a), which
shows a considerable degree of homology with EGF and
which can be produced by both epidermal cells and by
macrophages in healing wounds. TGF-a binds to the
same receptor on target cells as does EGF and has the
same mitogenic effect. In this way TGF-a may be a direct
mediator of wound healing.
3. Transforming growth factor j8. Transforming growth
factor p (TGF-fJ) is a polypeptide, first discovered in
culture media conditioned by transformed cells, but pro-
duced by almost all cell lines in culture. In the presence
of EGF it acts as a mitogen, but in some assays it has also
been found to inhibit growth. It is possible that these con-
tradictory actions may be a reflection of the different
types of assay used and may not tell us much about what
is happening in vivo. There is, however, good evidence
that macrophages in healing wounds express mRNA for
TGF-fJ as well as for TGF-ct. TGF-J3 has also been shown
to be a powerful chemoattractant for monocytes and its
release from the first wave of inflammatory cells migrat-
ing into the wound may act as a mechanism for recruit-
ing additional monocytes/macrophages. Studies from
fetal wound healing suggest that TGF-pl may be an
important cytokine in scar formation. Fetal skin has very
low levels of TGF-fJl and fetal wounds are able to heal
without scarring. In animal models, antibodies to TGF-(31
and p2 are also able to reduce scarring.
Cytokines
'Cytokine' (Greek kytos = vessel, cell + kineein - to move)
is the term used for a group of protein cell regulators that
includes such members as lymphokines, monokines,
interleukins and interferons. These are low molecular
weight proteins (usually less than 80 kDa). They tend to
be produced rapidly and locally and can act in either an
autocrine or a paracrine fashion. They are produced by a
wide range of cells and have many overlapping actions
which are mediated by their binding to high affinity
receptors on their target cells. The response of an indi-
vidual cell to a given cytokine is dependent on the cell
type, what other chemical signals are being received at
the same time, and the local concentration of the cytokine.
Two cytokines which play a significant role in wound
healing are interleukin 1 (IL-1) and tumour necrosis factor
a (TNF-a) (syn. cachectin).
1. IL-1 (formerly known as endogenous pyrogen) is a
small (17 kDa) protein which is produced by a wide
variety of cell types, including macrophages and epider-
mal cells. IL-1 has many biological actions which, in rela-
tion to healing, include a proliferative effect on dermal
fibroblasts and upregulation of collagen synthesis by the
fibroblasts. It also increases collagenase production and
this may be one of the ways in which the collagen in
wounds is remodelled so as to achieve maximal tensile
strength.
2. TNF-a is another monocyte /macrophage product
which is released following tissue injury or infection. It is
the main factor responsible for macrophage-mediated
tumour cell killing and is also responsible for the wasting
(cachexia) which is seen in certain chronic bacterial and
parasitic infections. Its biological activity has a remark-
able overlap with that of IL-1, although it does not appear
to have the immunoregulatory functions of that molecule.
Its receptors, however, are quite distinct from those of
IL-1 and presumably the similarities in their actions indi-
cate that they stimulate the same 'second messenger'
systems. The expression of TNF-a by monocytes and
macrophages requires activation of these cells. This may
326
WOUND HEALING
32
be brought about by interaction with fibrin (which is
always present in wounds), binding of TGF-p, the action
of a-interferon and the action of endotoxin.
3. TNF-a is a potent stimulus for the ingrowth of new
blood vessels in healing wounds, being not only chemo-
tactic for endothelial cells but also the agent responsible
for the focal degradation of capillary basement mem-
branes which precedes the migration of endothelial cells
into a healing wound.
4. Both TNF-a and IL-1 play an important role in
recruitment of inflammatory cells to the injury sites by
regulating expression of adhesion molecules on the
surface of endothelial cells.
Important growth factors and
cytokines in healing
PDGF, EGF, TGF-a and TGF-p (which appears to
have a role in scarring).
IL-1 , TNF-a.
REPAIR IN SOME SPECIALIZED
TISSUES
Bone
The processes involved in the early stages of fracture
healing are basically the same as those which have been
described in the foregoing sections. Thus the tissue defect
created by the fracture is, in the first instance, filled by
granulation tissue similar to that in large open wounds.
Later, more specific features peculiar to bone are imposed
on the basic model of healing. These are necessary
because bone, unlike soft tissues, has a mechanical and
weight-bearing role. Two types of specialized cell play a
central role:
• The osteoblast, which lays down seams of uncalcified
new bone (osteoid)
* The osteoclast, a multinucleated cell, probably of
macrophage lineage, which resorbs bone and which,
therefore, remodels the new bone.
Stages of fracture healing
1 . When a bone is fractured, tearing of blood vessels
leads to haemorrhage, hence the defect between the frac-
tured ends of the bone becomes filled with blood clot and
other plasma-derived proteins. As in any other tissue, the
injury elicits an acute inflammatory reaction, although the
degree of neutrophil infiltration is mild. The combined
effect of the haemorrhage and the inflammatory oedema
causes loosening of the periosteum from the underlying
bone ends and this results in a fusiform swelling at the
fracture site. Some degree of bone necrosis is almost
inevitable and is due to the blood supply to some areas
being cut off as a result of damage to blood vessels. It
takes 24-48 h for the first morphological evidence of bone
necrosis to become apparent, the marrow being the site of
the first changes. Fat necrosis is seen and, if haemopoietic
marrow is involved, the cells lose their nuclear staining.
As far as the bony tissue itself is concerned, the extent
of necrosis depends on the anatomy of the local blood
supply, and some sites such as the talus, the carpal
scaphoid and the head of the femur are particularly likely
to show significant ischaemic necrosis after fracture.
Empty lacunae, the dead osteocytes having disappeared,
are a reliable indication of bone necrosis. Macrophages
then invade the fracture site and commence the process of
demolition. This is followed by the formation of granula-
tion tissue, which also extends upwards and downwards
within the marrow cavity for a considerable distance from
the fracture site. Within the granulation tissue small
groups of cartilage cells begin to differentiate from con-
nective tissue stem cells.
2. Provisional callus is the term used to describe a cuff
of woven bone admixed with islands of cartilage which
serves to unite the severed portions of bone on their exter-
nal aspect but not across the gap between the bone ends.
The origin of the callus is from two sources, and the rela-
tive proportions of these vary depending on a number of
factors. The first and more important is the periosteum.
The cells on its inner aspects proliferate and begin to lay
down woven bone (i.e. bone in which the collagenous
osteoid tissue is not deposited in a lamellar or 'onion skin'
fashion but in series of short bundles of parallel fibres,
each bundle having a different orientation). Where the
periosteum has been raised from the external surface of
the bone, the new woven bone fills the gap so that there
are two cuffs of new bone around the periosteal aspect
of the separated fragments. These cuffs then extend
upwards and downwards until they meet, although there
is as yet no direct union across the gap between the sep-
arated bone ends. The degree of efficiency with which the
external callus formation occurs depends on the ade-
quacy or otherwise of the blood supply around the frac-
ture site. Some of the new blood vessels are derived from
the periosteum itself, while others come from the muscle
and other soft tissues which abut onto the fractured bone.
The amount of cartilage admixed with this periosteal new
bone is small in human fractures which are healing well,
but tends to be greater in cases where the local blood
supply is poor or where the fractured bone ends have not
been properly immobilized. The second source of provi-
sional callus is the medullary cavity, where, following
the formation of granulation tissue, fibroblasts and
osteoblasts start to proliferate and lay down bone matrix.
327
32 "
POSTOPERATIVE
Some of this is deposited on trabeculae of dead bone,
while the remainder forms new trabeculae. Well after the
provisional callus has been formed, the clot, which fills
the gap between the fragments, is invaded, first by
granulation tissue capillaries and then by osteoblasts.
Ossification within this gap may occur as a primary event,
the osteoblasts being derived from the provisional callus.
In some cases the bone ends are united by fibrous tissue
and over a period of time this is replaced by woven bone.
This takes far longer than direct ossification and is more
likely to occur if the fracture has not been properly immo-
bilized or if there is any other factor present which is
likely to inhibit healing (i.e. infection or extensive and
severe periosteal damage). Occasionally the fibrous tissue
filling the gap is not replaced by bone (non-union) and
weight bearing by the affected limb is not possible. In
cases of delayed or non-union some improvement may be
brought about by electrical stimulation, which appears to
accelerate ossification at fracture sites. Once union has
occurred and the patient is bearing weight, the lumpy
new cortical bone gradually becomes resorbed and
smoothed out and the excess medullary new bone is simi-
larly removed, with restoration of a normal medullary
cavity. Woven bone, which is quite rapidly formed and
which is much less efficient at weight bearing, is resorbed
completely and is replaced by lamellar bone. This is a
lengthy process of remodelling and restoration to normal
may take up to a year.
Nervous tissue
Central nervous system
Most neurons cannot be replaced once they have been
lost, although there is some evidence to suggest that a
limited degree of regeneration can take place in the
hypothalamic-neurohypophyseal system. In contrast to
the peripheral nerves, where injury is not associated with
any marked tendency towards scarring, necrosis within
the central nervous system elicits the proliferation of glial
cells, which, together with the ingrowths of capillaries,
may constitute a physical barrier to the regeneration of
new neuronal fibres. Recent work using bone marrow-
derived stem cells is challenging these concepts and this
area is likely to see major advances in the next 5 years.
Peripheral nerves
When an axon is severed, the nerve cell shows chromato-
lysis (i.e. it swells and the Nissl granules, which represent
zones of the endoplasmic reticulum studded with many
ribosomes, disappear). The axon swells and becomes ir-
regular, and its Iipid-rich myelin sheath splits and later
breaks up. The surrounding Schwann cells proliferate and
accumulate some of the lipid released from the damaged
myelin. Soon new neurofibrils start to sprout from the
proximal end of the severed axon and these invaginate the
Schwann cells, which act as a guide or template for the new
fibrils. The neurofibrils push their way down through the
Schwann cells at a rate of about 1 mm per day. Eventually
they may reach the appropriate end organ and their myelin
sheaths are reformed as a result of the secretory activity of
the Schwann cells; in this way, a degree of functional recov-
ery is attained. In some instances neurofibril sprouting
takes place but the fibrils do not grow down existing
endoneurial channels, and grow instead in a haphazard
fashion. The end result may thus be a tangle of new nerve
fibres embedded in a mass of scar tissue. This produces a
'traumatic' or 'stump' neuroma.
FACTORS AFFECTING WOUND
HEAyNG
Failure to heal satisfactorily can be the result of either
systemic or local factors.
Systemic factors
Nutrition
The state of nutrition of the patient is a potent factor in
determining the success or failure of the healing process
(see Ch. 10). Malnutrition causes depression of the
immune system and hence wound infection, and the
inflammatory response to this may delay healing.
Deficient protein intake may inhibit collagen formation
and so inhibit the regaining of tensile strength. In this
regard, sulphur-containing amino acids such as methion-
ine seem to be particularly important, and increasing the
intake of this amino acid alone can partially offset the
effects of a low protein intake on wound healing. Vitamin
C has an important role in healing. It has been known
since the seventeenth century that scurvy is associated
with poor healing of wounds and fractures. Indeed, there
are colourful descriptions of old wounds, acquired hon-
ourably or otherwise in combat, breaking down after the
onset of scurvy. Lack of vitamin C has been found to
inhibit the secretion of collagen fibres by fibroblasts; this
is due to a failure of hydroxylation of proline in the endo-
plasmic reticulum of the fibroblast. In addition, vitamin C
concentrations in biological fluids appear to affect the
production of galactosamine and hence the deposition of
chondroitin sulphate in the extracellular matrix of granu-
lation tissue. Vitamin A has important functions in
relation to morphogenesis, epithelial proliferation and
epithelial differentiation, and the latter two are believed
to be important in wound healing. A role for zinc in
328
WOUND HEALING
2
wound healing was discovered more or less by accident.
In the course of a study on the effects of certain amino
acids on wound healing, a phenylalanine analogue that
had been expected to impair healing instead accelerated
it. Careful study of this analogue revealed that the sample
used had been contaminated by zinc. Further studies
showed that zinc does indeed accelerate the healing of
experimental wounds. Zinc deficiency such as is found in
patients who have been on parenteral nutrition for long
periods and in patients with severe burns, is associated
with poor healing and this is reversed by the administra-
tion of zinc.
Steroid hormones
Many studies show that glucocorticoids have an
inhibitory effect on the healing process and on the pro-
duction of fibrous tissue. Steroids are therefore adminis-
tered in situations where inappropriate scarring is taking
place, such as in interstitial fibrosis in the lung. It is still
not clear whether steroids exert their effect indirectly by
damping down the inflammatory process or whether they
act directly on fibroblasts to alter collagen deposition.
Local factors
Presence of foreign bodies or infection
The presence of infection or of a foreign body increases
the intensity and prolongs the duration of the inflamma-
tory response to injury. It is worth remembering that frag-
ments of dead tissue, such as bone, and other elements of
the patient's own tissues that have become misplaced,
such as hair or keratin, act as foreign bodies.
Excess mobility
The oedema that occurs following tissue injury may lead
to immobilization of that part, hence the fifth cardinal
sign of inflammation: 'loss of function'. Although this can
be troublesome, it also has the benefit of aiding the
healing process. It will be clear to everyone that a frac-
tured bone is not going to heal unless it is immobilized.
Excess mobility in any tissue will impair healing and
prolong the time to full recovery
Vascuiar supply
The degree of arterial perfusion and the efficacy of venous
drainage play key roles in the healing of injured tissues.
Where the arterial perfusion is compromised by stenosis
or occlusion, a trivial injury may give rise to a dispropor-
tionate degree of tissue damage and healing may be
delayed or even completely inhibited. A good example is
diabetes mellitus. In patients with longstanding disease,
trivial injuries develop into chronic, non-healing ulcers.
Blood vessel disease affecting both the large muscular
arteries of the lower limb (atherosclerosis and its compli-
cations) and changes in the walls of arterioles and capil-
laries probably make the major contribution to failures of
healing. These patients are of course also susceptible to
infection (particularly if their diabetes is badly controlled)
and may also have a sensory neuropathy which makes
them more liable to sustain injuries to their extremities.
Adequate venous drainage is also important, and
impairment of this may play a part in the genesis of
chronic ulcers, which often occur on the anterior surface
of the legs in elderly patients. Histological examination of
the margins of these lesions suggests that drainage is
compromised by the presence of cuffs of polymerized
fibrin round the venules. This can, in part, be prevented
by administration of the synthetic steroid stanozolol.
Suboxygenation of normally perfused tissue, such as may
occur in the presence of severe anaemia, will also lead to
defective healing.
Factors modifying healing
• Nutrition malnutrition, vitamin deficiency.
• Steroids.
• Systemic disorders, e.g. diabetes.
• Vascular supply.
• Mobility of affected tissues.
• Infection.
COMPLICATIONS OF HEALING
££/*fi(-^
Although the basic processes involved in healing are
designed to be protective, they do occasionally go wrong.
This occurs as a result of a loss of control in the complex
interplay between the many varied cellular and chemical
processes. Two complications worthy of mention are
hypertrophic scar and keloid. Although these haunt all
surgeons, they are a particular problem for the plastic
surgeon. Hypertrophic scar is simply an overgrowth of
scar tissue which causes a raised firm ridge. When the
tissue overgrowth is so exuberant that it greatly exceeds
the borders of the scar, it is called a keloid. Unfortunately,
some patients have a tendency to form keloids (more
common in black people) and hence excision of the keloid
only results in more keloid.
It is worth remembering that, due to the contraction
that occurs during wound healing, excessive tissue
destruction, especially around joints, may result in con-
tractures and joint deformity.
329
32
POSTOPERATIVE
Summary
• Wound healing is a complex process
relying on the integrated actions of the
coagulation system, the inflammatory
response and the chemical mediators
required to stimulate cell proliferation and
protein secretion.
• The processes are fundamentally the same
in cleanly incised wounds and in large
open wounds.
• A similar process also occurs in specialized
tissues such as bone, with some changes
related to functional demands of that
tissue.
• The healing process can be modified by
many factors, including nutritional status,
steroids, infection and excess mobility of
affected parts.
• Although designed to be protective,
complications as a result of contractures
and exuberant scar formation produce
clinically significant morbidity.
Further reading
Kirsner RS, Eaglestein WH 1993 The wound healing process.
Dermatology Clinics 11(4): 629-640
Lakhani SR, Dilly S A, Finlayson CJ 1 998 Basic pathology: an
introduction to the mechanisms of disease, 2nd edn. Edward
Arnold, London, pp 78-86
Majno G, Joris 1 1996 Wound healing. In: Cells, tissues and
disease. Principles of general pathology. Blackwell Science,
Oxford, pp 465-485
Singer AJ, Clark RAF 1999 Cutaneous wound healing.
New England Journal of Medicine 341: 738-746
Waldorf H, Fewkes J 1995 Wound healing. Advances in
Dermatology 10: 77-96
330
Responses of connective tissue
and bone
1/1/. J. Ribbans, M. Saleh
Objectives
• Appreciate that bone and connective
tissues are not static but are living,
dynamic and responsive to their changing
environment.
• Understand the responses of connective
tissue and bone to trauma.
• Be aware of the factors modifying the
structure, strength, growth of bone and
connective tissue.
• Understand the response of bone to
various surgical procedures.
• Appreciate the inbuilt redundancy that
often permits patients to overcome
physical and functional defects.
• Recognize the importance of restoring
function following trauma and surgical
intervention.
INTRODUCTION
We shall consider the responses of connective tissues and
bone to their environment and stresses/ including trauma
and iatrogenic (Greek iatros = physician + -gen = to
produce) interventions, which include operative surgery.
There is a tendency to regard the skeleton and connective
tissues as static but they are responsive and dynamic
(Greek dynasthai = to be able). Do not regard any of these
structural tissues as being simple; they are just as complex
as any other parts of the body. Although bone is inter-
spersed with inorganic calcium phosphate, it is largely
composed of type I collagen. Collagen can be laid down
by fibroblasts or reabsorbed, and in bone, calcium phos-
phate can be laid down, remoulded and reabsorbed.
The dynamic properties are well illustrated by the
response to stress. Just as muscles undergo hypertrophy
(Greek hyper = over + trephein = to nourish) when exer-
cised, so do the tendons that transmit their tension. If
bone is stressed, new bone is laid down to compensate; if
the direction of the stress changes, the architecture of the
bone adjusts to meet it. In contrast, connective tissues and
bones that are not stressed respond rapidly by undergo-
ing atrophy, including bone decalcification. Striking
examples are the changes that occur in the ligaments and
bones of women during pregnancy, and in the muscles
and skeleton of astronauts in space when the effects of
gravity are removed.
None of the tissues works in isolation and all of them
are involved in movements that require them to function
in concert (Latin com- = with + certare = to strive).
Fortunately we are constructed in a fashion that has
inbuilt redundancy (Latin re- = again + undare = rise in
waves; to overflow). If there is a failure of one part, there
is 'spare' function available that can compensate. For
example, if the hip is stiff, part of its function can be taken
over by swinging the pelvis, using vertebral flexion and
rotation, in order to swing the affected leg forward, using
the other hip joint as a fulcrum. Animals can survive
happily with severe disabilities; young humans are
remarkably adaptable when born with congenital defects
and functional incapacities. However, it is possible to
overcome or alleviate many functional losses; a simple
splint may provide lost support, an ankle foot orthosis
(Greek orthos = straight; the straightening of a distorted
part) can compensate for foot drop. An artificial limb
(prosthesis; Greek pros = to + thesis = putting) provides
effective replacement of a lost limb. Orthopaedic sur-
geons can aid fracture fixation using internal and external
fixation, and repair or divert tendons to overcome paral-
ysis or rupture. The field of activities constantly increases
as joint replacement, limb lengthening, limb transplanta-
tion and minimal access procedures are developed and
extended.
Make sure that you acquire a deep understanding of
the connective tissues; they are fundamental to the
success of surgical procedures.
Trauma
1. Damage can occur from sharp or blunt injury, or
from a combination of the two. It may be direct or indirect,
331
POSTOPERATIVE
open or closed (see Ch. 2). As a result of the injury, deep
tissues may be distracted or misaligned and become
incorporated within a large haematoma. Open, contami-
nated wounds are at increased risk of infection.
2. Operative surgery is a form of trauma but gentle
handling of tissues, perfect haemostasis and meticulous
technique, as advocated by the great American surgeon
William Halsted (1852-1922), together with observance of
sterile precautions minimize its effects. Injury may be
increased by rough handling, thermal damage from using
diathermy haemocoagulation, power-driven tools, and
bone cement. Healing can be prejudiced by inserting
unsuitable materials, such as excessive or irritating
sutures.
3. The initial injury may be compounded by the effects
of immobilization and disuse on bones, joints, muscles,
tendons and ligaments, including those not directly
involved within the surgical field.
coNi^cr^
Collagen
1 . This is a family of proteins accounting for about one-
third of the total body protein, comprising about 90% of
the organic matrix of bone. The molecule is about 280 nm
long. A number of polypeptide chains are involved. Type
I is the most widely distributed in fascia, dermis, cornea
and tendon, providing excellent tensile strength. Type II
is the main component of hyaline (Greek hyalos = glass)
cartilage and also occurs in the nucleus pulposus of the
intervertebral discs. Type III forms part of the wall of
blood vessels, heart valves, dermis and the network of
connective tissues in the walls of organs. Type IV is
present in basement membranes. Type V is widely dis-
tributed in membranous sheaths of muscles, Schwann
cells and in basement membranes.
2. Collagen was once thought to be relatively static but
it can be rapidly laid down or degraded. Excessive colla-
gen formation occurs in hypertrophic and keloid scars,
and also in rheumatoid arthritis. In old age, collagen
atrophy is progressive. It is defective in the syndrome
described in 1896 by the French physician Bernard
Marfan (1858-1942) and in the overstretched collagen
syndrome descibed by two dermatologists, Edvard
Ehlers (1901) in Germany and Henri Danlos (1908) in
France.
Elastic fibre
1. This is composed of the protein elastin enclosed
within elastic fibrils. It occurs in the aorta and its large
branches, in the ligamentum nuchae, the lungs and the
skin. It may be difficult to distinguish between elastic
fibres and altered collagen fibres.
2. Elastin is generated by fibroblasts and elastic
fibres appear to be produced by smooth muscle cells.
Although stable in most circumstances, elastic fibres are
rapidly destroyed by elastase, an enzyme produced by
some microorganisms. Elastic fibres are reduced in old
age, the most obvious feature being the loss of tautness
of skin.
Ground substance
This consists of glycoproteins and proteoglycans (pre-
viously called mucoproteins), which include hyaluronic
acid and chondroitin. They are synthesized in fibroblasts
and osteoblasts.
Muscle
1. Skeletal muscle is often stated to be incapable of
regeneration but this is not entirely so. A damaged
muscle cell initially undergoes degeneration, followed by
regeneration. Recovery depends heavily upon the ade-
quacy of revascularization from surrounding tissues.
Necrotic tissue is removed initially and replaced by satel-
lite pluripotent undifferentiated cells in the near vicinity,
as mature myofibroblasts lack ability to regenerate and
divide. The cells of the original syncytium dedifferenti-
ate, undergo cell division, then fuse, recreating the fibre.
The satellite cells may account for one-third of all muscle
nuclei of newborns, but this falls to less than 5% in
adults, clearly affecting the relative ability of newborns
and adults to recover from injury. Myoblasts appear and
fuse to form myotubes, which coalescence into muscle
fibres. This occurs within a newly laid down extracel-
lular matrix and basal lamina surrounding the muscle
fibres.
2. If part of a muscle is destroyed, function is restored,
not by cell hyperplasia (Greek hyper - over + plassein =
to form) but by hypertrophy (trephein - to nourish); the
individual fibres thicken up, at best creating a muscle
mass comparable with the original bulk. When a muscle
is transected, the ends contract and separate, the inter-
vening space being filled with haematoma. This is even-
tually replaced by collagenous scar tissue, so that a
single bellied muscle is transformed into a double bellied
one.
3. Muscle is frequently incised to facilitate exposure.
Whenever possible, split muscle along the line of the
fibres rather than dividing it across them. Incisions paral-
lel to the fibres are expected to disrupt functional recov-
ery less than transection of the muscle belly. However, it
has been shown that fibroblasts lay down collagen fibrils
at right angles to the axis of the surgical incision in the
332
RESPONSES OF CONNECTIVE TISSUE AND BONE
33
muscle. Where scar tissue intervenes between muscle
fibres and the motor endplate, the isolated fibres exhibit
features of denervation. Excessive scar tissue formation
affects the ability of a muscle to contract and lengthen
normally, A muscle transected at mid-belly recovers only
about half its ability to develop tension and exhibits about
20% reduction in shortening during contraction.
4. Apart from direct laceration by scalpel, scissors or
diathermy muscle is injured by excessive pressure from
instruments causing contusion (Latin tundere = to bruise),
resulting in postoperative oedema, bleeding and acute
inflammation. Provided the muscle unit remains vascu-
larized and the patient can mobilize, functional recovery
is usually adequate, with minimal scarring.
5. Ischaemia results from de vascularization, or from
excessively long application of a tourniquet. Transient
ischaemia usually recovers completely but, if it exceeds
several hours, irreversible changes occur in the myo-
fibrils, with dilatation of mitochondria and sarcoplasmic
reticulum.
6. Postoperatively, ischaemia may develop secondary
to compartment syndrome. Muscle that is starved of
blood supply undergoes fibrosis, described in 1 881 by the
German surgeon Richard Volkmann (1830-1889). Too
tight bandaging, or application of plaster, and limb
swelling within them may cause ischaemia.
7. If a muscle is denervated or transected, functional
recovery depends upon the degree of nerve regeneration
across the surgical incision, and the completeness of
reinnervation.
8. Within the healing environment, dense scar tissue
forms and can interfere with muscle regeneration and
functional recovery. Experiments in the small muscles of
rodents suggests that, in a fully re vascularized area, com-
plete muscle regeneration is possible. This seems unlikely
in humans and partial recovery is generally the norm. The
gap usually fills with dense scar tissue. Myotubes may
penetrate the fibrous tissue but complete regeneration is
unusual.
9. Following division of the Achilles tendon, there is
some evidence of a change in the proximal muscle fibre
type from type I slow-twitch fibres to type II fast-twitch
fibres.
10. Prolonged immobilization adversely affects the
functional recovery of muscles following injury. Indeed,
it has been reported that protein synthesis starts to
decrease within 6 h of applying an immobilizing cast. On
the other hand, repetitive loading increases the number
and size of the muscle cell mitochondria, muscle glyco-
gen concentration and oxidative capacity. Active mobi-
lization favours a rapid and more complete regeneration.
Low-tension high-repetition exercise promotes muscle
endurance, while high-tension low-repetition exercise
promotes muscle strength.
Key point
• Disuse atrophy occurs in skeletal muscle
following prolonged immobilization.
11. These features can be minimized by immobilizing
muscles under tension. Muscle mass and strength are lost
quickly following immobilization, and fatiguability
increases. For example, lying in bed with knee extended
causes more rapid functional decline in the relatively
relaxed quadriceps than in the hamstrings, which are
relatively stretched. Therefore, when placing an external
fixator fine wire through muscle and into bone, prefer-
ably hold the muscle in an eccentric position while
passing the wire. For instance, as a wire passes through
the gastrocnemius-soleus complex dorsiflex the ankle to
ensure the muscle is transfixed in a lengthened position,
minimizing the risk of the development of an equinus
(plantar-flexed) deformity at the ankle.
12. Muscle sensitivity to insulin is decreased during
immobilization so it is more difficult for glucose to enter
it, depriving it of energy supplies and allowing lactate
to accumulate. Aerobic metabolism of fat is reduced.
During postoperative recovery the ability of muscle to
synthesize protein is reduced because of increased levels
of corticosteroids.
13. Heterotopic (Greek heteros = other + topos = place;
displaced) ossification occurs in some patients within soft
tissues, especially muscle, and following certain proce-
dures. The pathogenesis is uncertain but may involve
damage to muscle, tendon and periosteum, residual bone
debris, and haematoma formation in the presence of
pluripotent (Latin pluris = more + potentia = power;
multiple potential), uncommitted fibroblasts. On careful
inspection, up to 30% of postoperative hip replacement
radiographs reveal evidence of ossification although re-
exploration and bone excision is required in less than 1 %
of patients. The incidence is greatest in males, younger
patients and following an anterolateral approach to the
hip joint. The new bone is found within fascial connective
tissue with extensions into the muscle mass. There is an
acute rise in the levels of serum alkaline phosphatase
during the early weeks following operation.
Tendons
1 . Tendons (Greek tenon = sinew) are composed of fas-
cicles (bundles) of collagen. Each fascicle contains fibrils
of predominantly type I collagen, produced by fibro-
blasts, embedded in a proteoglycan matrix. Each bundle
is surrounded by an endotenon of loose connective tissue
and the whole tendon is surrounded by an epitenon.
333
POSTOPERATIVE
2. Many tendons are enclosed in a tendon sheath, espe-
cially those that change direction abruptly, such as flexor
tendons of the hand. The tendon sheath acts as a pulley
and prevents / bow-stringing / of tendons. The synovial
membrane on its inner surface combined with the
epitenon serve as sources of lubricating fluid for the
tendon. The tendons themselves are relatively avascular;
blood reaches them at isolated points through flimsy
attachments termed vinculae (Latin vincire = to bind).
These tendons possibly have a dual pathway for tendon
nutrition - through blood vessels and also by synovial
diffusion. Tendons not surrounded by a sheath have a
paratenon surrounding them, such as the Achilles tendon;
they are known as vascular tendons and receive vessels
from many points.
Key points
• Damage to the vinculae that bring blood
vessels to the tendons seriously prejudices
healing.
• Damage to tendon sheaths and paratenon
roughens the surfaces and generates
irregularities and adhesions.
3. Repetitive loading is a stimulus for increase in
strength, size, matrix organization and strength of the
insertion into bone. Endurance training in optimal posi-
tion, with minimal resistance, facilitates revascularization
and can result in an increase in strength of up to 3(MrO%.
4. However, the overall blood supply of tendons is not
bounteous and certain areas within them are recognized as
being relatively avascular. They are prone to damage and
disability because of their inability to repair; for example,
the supraspinatus tendon in the shoulder, the Achilles
tendon, and the tibialis posterior tendon at the ankle.
5. 'Vascular' tendons undergo repair by the normal
inflammatory response. Macrophages and fibroblasts fill
the tendon gap. Type I collagen predominates in the
initial healing process, orientated at this early stage
perpendicular to (across) the long axis of the tendon.
Subsequent remodelling and reorientation follows but
maximum strength is not achieved for 5-6 months.
6. The timing of mobilization is crucial following
tendon repair. Too early mobilization weakens the repair
and leads to gap formation between the tendon ends.
Early controlled passive motion appears to stimulate
intrinsic repair from the epitenon itself, and improves
tendon strength.
7. Prolonged immobilization of flexor tendons of the
hand leads to increased adhesions and stiffness resulting
from ingrowth of scar tissue from the surrounding sheath.
Again, early controlled passive movement gives optimal
restoration of flexibility and strength, especially of the
finger flexors.
Fascia and compartment syndromes
1. The upper and lower limbs are divided into rela-
tively inelastic compartments bounded by fascia and
bone (Fig. 33.1). Each contains soft tissues, principally
muscle, tendon and neurovascular structures. The devel-
opment of a compartment syndrome after trauma is well
recognized (see Ch. 2). Similar changes can occur after
elective surgery to the limbs. The boundaries of each com-
partment allow only a finite amount of expansion before
ischaemic changes develop. Fig. 33.2 outlines the patho-
genesis of a compartment syndrome.
2. Postoperative swelling and bleeding increase the
volume, and therefore the pressure, within compartments.
3. Monitor 'at risk' patients clinically after operation by
testing sensation and movement; this is not possible if you
have used nerve block anaesthesia. It is possible to measure
objectively the pressure within, for example, the anterior
tibial compartment, to detect an abnormal rise in pressure.
Key points
• Avoid excessive tourniquet inflation times
because this results in postoperative swelling
within compartments.
• Drain compartments within which
postoperative bleeding is likely.
Ligaments
1. Ligaments (Latin ligare = to bind) span joints and
provide stability. Additionally, they have important pro-
prioceptive (Latin proprius = one's own + receptive; sense
of one's position) and nocioceptive (Latin nocere = to hurt;
pain perception) functions because of the specialized
nerve endings embedded within them.
2. Fibroblasts within the ligaments lay down collagen
(90% type I), and some elastin fibres in an extracellular
matrix. The collagen fibres are generally laid down along
the direction of the tensile forces but not as rigidly as in
tendons. Ligaments are relatively avascular, the most
important source of vessels being the surrounding soft
tissue rather than the osseous attachments. The anterior
cruciate ligament within the knee derives most of its
blood supply from the synovial membrane, which
surrounds it.
3. Repetitive loading promotes increased strength, size,
matrix organizition and attachment to bone.
334
RESPONSES OF CONNECTIVE TISSUE AND BONE
Bone
Anterior compartment
Lateral compartment
Deep posterior compartment
Superficial posterior compartment
Bone
Anterior compartment
Posterior compartment
Tibia
Anterior
intermuscular
septum
Interosseous
membrane
Fibula
Posterior
intermuscular
septum
Transverse
intermuscular
septum
Radius
Interosseous
membrane
Ulna
Antebrachial
fascia
Fig. 33.1(a) Transverse section of leg, (b) transverse section of forearm.
4. Repair of a damaged extra-articular ligament, such
as the medial collateral ligament of the knee, is induced
by the normal inflammatory response. The resulting
haematoma is rapidly invaded by inflammatory media-
tors. Vascular granulation tissue contains many fibro-
blasts, laying down predominantly type III collagen,
which provides early stability. After several weeks, a
period of remodelling and maturation commences, which
may be completed only after a year. The collagen type is
gradually converted back to type I.
5. Operative repair of intra-articular ligaments, such as
the anterior cruciate ligament of the knee, is not associated
with great success. The blood supply is sparse and synovial
fluid dilutes the initial haematoma, inhibiting the normal
repair mechanisms. Usually reconstruction is necessary,
either with a hamstring tendon or with a part of the patella
tendon that includes at one end a portion of bone from the
tibial tubercle and at the other end a portion of patella.
Key point
Careful apposition of the divided ends, with
minimal disturbance of the local soft tissues
which carry the blood supply, are essential
requirements for successful repair.
6. Immobilization of a joint following operation com-
promises the biomechanical properties of a previously
healthy ligament. Tensile strength, elasticity and tough-
ness deteriorate, only slowly reversed as joint movement
is resumed.
7. Joints immobilized after operation need to be
splinted in a 'position of function' to avoid unnecessary
contractures of the ligaments. Immobilization should be
minimized to encourage recovery of the normal biomech-
anical properties of the stabilizing ligaments.
Synovial membrane
1. The function of synovium within articulations and
around moving tendons is to provide synovial fluid for
lubrication and nutrition and to remove unwanted ele-
ments from the area. Its superficial cells are served by a
dense subsynovial plexus of vessels. Muscle bellies also
slide over each other with minimal friction, although this
is often ignored or overlooked. The apposed smooth
external investing fascias must be separated by some form
of synovial fluid. A.K. Henry, the poetic Irish surgeon-
anatomist, eloquently describes the appearance of vastus
intermedius muscle, when the overlying muscles are sep-
arated, as a 'silvery fish-like belly'; it is shiny and slippery
like the scales of a freshly caught fish (Henry 1945).
335
POSTOPERATIVE
Osseous
I
Vascular
Tissue trauma
—
i
r T £ >
Increased
intracompartmental fluid
Tissue swelling
Increased
intracompartmental pressure
i
Decreased pressure gradient
between arteriovenous
vascular beds
j
Decreased blood flow
J
Increased metabolic deficit
Fig. 33.2 The vicious cycle of haemodynamic changes that occurs in the development of a compartment syndrome.
2. Although the secreted fluid resembles white of egg
(Greek ovon - egg), the origin of the name is obscure. The
membrane invests many tendons and joints within the
body. Membrane injury from trauma or operation
increases its vascularity, cellular content and permeabil-
ity resulting in increased production of synovial fluid
and white blood cells. Vacuum drainage of the joint may
be valuable in removing excess synovial fluid.
3. Synovial fluid is viscous, lubricating and nourishing
joint and tendon surfaces. Its viscosity and pH varies in
diseases such as osteoarthritis and rheumatoid arthritis.
Changes in the constituents can be detected by infrared
spectroscopy and as the viscosity falls the lubricating
function is reduced.
4. Haemarthrosis (Greek haima = blood + arthron = joint
+ -osis = morbid process), following injury or operation,
stimulates the synovial layer to phagocytose the erythro-
cytes and haemoglobin molecules. Type A synovial cells
are probably the most active phagocytes. Ingested blood
may form whorled bodies, known as siderosomes (Greek
sideros = iron), within the cells. The haemarthrosis induces
a chronic inflammatory response within the subsynovial
layer and there is evidence of angioneogenesis (Greek neos
- new), cellular hyperplasia and some villous prolifera-
tion within the membrane. Large amounts of ingested
blood may be toxic to the phagocytic cells, killing them.
The dead cells release enzymes such as collagenase and
neutral proteinase, which are potentially harmful to the
joint and, in particular, to articular cartilage. Synovial iron
deposits can still be found for up to 2 years following a
major haemarthrosis.
5. Inflammatory disease processes, such as rheumatoid
arthritis, mediate many of their pathological processes
by direct action upon the synovium. The inflammatory
stimulus causes cellular proliferation and increased vas-
cularity. The inflammation, secondary to synovitis and
effusion, causes joint swelling and distension of the joint
capsule and ligaments. The latter may lose their stabiliz-
ing influence upon the joint, increasing deformity and
joint destruction. The joint articular cartilage is gradually
destroyed by the formation of a pannus of inflammatory
vascular tissue, which spreads from the junction of the
336
RESPONSES OF CONNECTIVE TISSUE AND BONE
33
cartilage and synovium until it envelops the whole
articulation. The detrimental effect of the pannus is due
to the direct proteolytic effect of its enzymes and the
mechanical effect of its covering presence, depriving the
articular cartilage of the benefits of the synovial fluid.
A combination of the osteoclastic cytokine action
within the overlying pannus, relative inactivity and drug
treatment causes the subchondral bone to become rela-
tively demineralized and osteoporotic.
Joint instability can cause life-threatening changes to
the cervical spine, affecting the safety of surgical proce-
dures. Replacement will be undertaken in a joint more
prone to instability and periarticular fracture. At times /
different artificial joint designs will be required, e.g.
increasingly stabilized prostheses. Wound healing may be
compromised as a result of the patient's drug therapy and
the generally more delicate nature of the adjacent soft
tissues. Any inflamed synovial tissue, with its hypervas-
cularity, is more at risk of infection from systemic causes.
The extra-articular sites of synovial tissue undergo
changes causing similar damage to tendons, affecting
strength and ultimately leading to rupture in many cases.
Tendon repair following rupture may be impossible
because of the poor quality of the tissue: a series of tendon
transfers have been described for such eventualities.
B
Key point
Be aware of the changes that synovial tissue
has undergone, and the consequent limitations
placed upon you.
JOINTS
%^.^^^^i\^J^^4-^f^!M^'^'^.^Si
Some joints may not permit movements, such as
synarthroses (Greek syn = together) between the bones of
the skull. Amphiarthroses (Greek amphi = both) joined by
fibrocartilage, as in intervertebral discs, or synovial mem-
branes, as in the pubic symphysis, permit very little
movement, Di arthroses (Greek dia = through) are freely
moveable, as in the hip and shoulder joints; the bone ends
are covered in articular cartilage and they are enclosed in
a synovial membrane (Table 33.1).
Joints can be damaged if weight is exerted through
them in an abnormal fashion. This is very true of the
complex knee joint. Weight should be transmitted equi-
tably between the femoral condyles, through the menisci
and the tables of the tibial platform.
Be aware of the importance of axes and alignments in
determining the forces on joints and strains and stresses
on musculotendinous units. In the lower limb, there are
various lines along which bones rotate or are conceived to
revolve, or about which the parts are symmetrically
arranged (Greek axon, Latin axis - an axle) (Fig. 33.3):
• Anatomical axis of bones: a line running along the
midpoint of the femur and tibia.
• Vertical axis: from the body's centre of gravity to the
ground.
• Mechanical axis: a line that normally passes from the
centre of the femoral head to the centre of the ankle
joint through the centre of the knee. Any deviation of
this axis, such as congenital deformities, operative or
post-traumatic deformity, may cause uneven loading
on joints, with consequent arthritis and instability.
Lubrication of synovial joints
Synovial joints are lubricated by synovial fluid. The
science of friction, wear and lubrication is known as
tribology (Greek tribein = to rub). Lubrication acts to
Hip centre
Mechanical
axis
Anatomical
axis
Knee centre
Ankle centre
Body centre
of gravity
Vertical axis
Fig. 33.3 Lower limb axes.
337
POSTOPERATIVE
^^uaunaa^saasBasuut
Table 33.1 Classification of joints
Joint type
Fibrous
Subtype
Examples
Characteristics
Movement
Skull sutures;
Bones joined by fibrous tissue
Variable from nil, e.g.
syndesmosis of the
continuous with periosteum or
skull sutures, to
inferior tibiofibular
perichondrium
considerable, e.g.
joint; interosseous
interosseous membrane
membrane of the
forearm
Cartilaginous
Primary
Physeal plate of the
growing long bones
May be temporary, e.g. during
bone growth and converts to
bone at the end of growth
None
Secondary
Pubic symphysis;
manubriosternal joint;
intervertebral discs
Joints are found in the midline.
Each bone is covered with
hyaline cartilage and joined by
a central fibrous tissue which
Slight movement
may cavitate, e.g. gel for discs
Synovial
Bone covered by hyaline
cartilage. Enclosed by fibrous
capsule, which is lined by
synovial membrane. Joint cavity
is filled with synovial fluid
derived from membrane
Plane
Acromioclavicular joint
Flat surfaces
Permits gliding or sliding
Hinge
Elbow joint
Hinge joint
Moves in one plane
Saddle
First metacarpotrapezial
joint
Biaxial joint
Permits circumduction
Condyloid
Metacarpophalangeal
joints
Biaxial
Permits movement in
two planes
Ball and
Hip; shoulder
Multiaxial
Circumduction. Amount
socket
of movement depends
upon depth of socket
and Ifgamentous
arrangement
Pivot
Forearm pronation/
supination; atlantoaxial
Uniaxial
Rotation
joint
reduce frictional resistance and wear. The coefficient of
friction for a synovial joint is lower than that achieved in
any synthetic (Greek syn - together + thesis - a placing;
putting together) bearing surface yet designed.
There are several mechanisms of lubrication (Fig. 33.4):
1. Hydrodynamic
2. Elastohydrodynamic
3. Weeping
4. Mixed
5. Boundary
6. Squeeze him
7. Hydrostatic.
A normal synovial joint relies predominantly upon mech-
anisms 2, 3 and 5. Artificial joints rely on 2 and 5.
Menisci
1. The menisci (Greek meniskos, diminutive of mene =
moon) increase the contact area in certain joints, partici-
pate in load distribution, act as shock absorbers and aid
in distribution of lubricating synovial fluid.
2. The long-term absence of all, or a substantial part of,
a meniscus is associated with increased risk for the devel-
opment of osteoarthritis.
3. The meniscus is composed primarily of type I colla-
gen, with lesser contributions from types II, III, V and VI.
The cellular elements responsible for the synthesis of col-
lagen and other constituents of the extracellular matrix
are termed fibrochondrocytes. The collagen fibres are
orientated predominantly circumferentially with a few
338
RESPONSES OF CONNECTIVE TISSUE AND BONE
3
Types of lubrication
jT >v
^SrtfiPS^*
Boundary
Load
Mixed
E lastohyd rody namic
Velocity
Viscosity
riw-.t ' ■ »fi n '.
\./
"^V^pra^^fl^'* 15
Hydrodynamic
NX
Lubrication mechanisms II
p-
Load
Velocity
Viscosity
III INI IIIIIBMII
Hydrostatic
Weeping
Squeeze film
Classical:
* Boundary;
low film factor <j> (very thin film) < ralher high m and wear rate
* Mixed:
higher film factor ih (discontinuous film), mixture ol boundary
and elastohydrodynamic i : highest friction and wear rate
* E lastohyd rody namic:
higher Itlm factor <D, film maintained through pressure shocks
*: relatively low coefficient of friction and wear rate, occurs
in replaced joints
* Hyd rody namic:
higher film lactor (D {thick film} ■: coefficient of friction and
wear rate low
In addition:
• Hydrostatic:
high pressure in fifm is maintained from external source (P)
• Weeping:
porous and deformable surfaces^ from which additional
lubricant is squeezed upon relative motion (eg cartilage,
'soft cushion bearing')
• Squeeze film:
structured surfaces prevent lateral flow of lubricant from
Ihe sliding interface
Fig. 33.4 Types and mechanisms of lubrication.
positioned radially, tying together the other fibres and
limiting motion.
4. The vascular arrangement of knee menisci is import-
ant for nutrition and the ability to repair. A circumferen-
tially arranged perimeniscal plexus sends radially
orientated vessels into the meniscus. Unfortunately, they
penetrate only 10-30% of the peripheral area. This has led
to the concept of the outer "red zone' and inner 'white
zone'. The synovium extends for a couple of millimetres
over the peripheral edges of the meniscus and contains
blood vessels. Within the 'white zone', nutrition is depen-
dent upon diffusion from the synovial fluid.
5. The ability of the meniscus to repair following a
sporting injury or degenerative tear depends upon the
site of damage. Within the 'red zone', repair can take
place along similar lines to other connective tissue struc-
tures. Vessels from the synovium and circumferential
plexus support this process. Success depends upon the
size of the lesion, the delay between injury and repair, and
the adequacy of the blood supply. Apposition of the torn
edges can be aided by meniscal suturing.
6. Most meniscal tears occur in the avascular zone and
are incapable of repair. Operation, usually through the
arthroscope, involves excision of the torn fragment to
prevent further propagation of the tear and to abolish
pain, clicking and occasional joint locking experienced
by the patient. If unstable segments are excised, later
development of osteoarthritis is minimized. While not
capable of repair, the meniscus may undergo remodel-
ling following partial excision in the 'white zone'. The
'raw area' resulting from the surgical removal of the torn
fragment fills with a fibrin clot and synovial-derived
cells. Later, the tissue appears, on gross inspection, to be
similar to fibrocartilage. It seems that this process is
related to the ability of meniscal fibrochondrocytes to
proliferate in the presence of haematoma-derived
factors.
Articular cartilage
1 . Articular cartilage is composed largely of an extra-
cellular matrix populated with relatively few chondro-
cytes. It consists of predominantly water, collagen (mostly
type II) and proteoglycans with link proteins. In contrast
to the opaque fibrocartilage seen in menisci, articular car-
tilage is hyaline. Synthesis of the matrix is increased by
moderate repetitive loading.
2. Mechanical loading of normal joints contributes to
maintenance of the articular cartilage but high shear
stress causes degeneration and loss of function.
339
POSTOPERATIVE
3. Small defects may heal spontaneously. Superficial
lesions do not provoke an inflammatory reaction because
there is no bleeding and chondrocytes cannot repair the
damage. They do not inevitably progress to full thickness
damage and osteoarthritis / as a thin layer of matrix may
form over the damaged surface. For deeper lesions, not
only the cartilage but also the subchondral bone is
breached. This allows bleeding from the deeper bone to
fill the defect and induce an inflammatory response. Some
mesenchymal cells assume the appearance of chondro-
cytes. However even 6 months after the injury the carti-
lage is not fully repaired. While areas of hyaline cartilage
may appear, there is a substantial amount of fibrous tissue
present. The ultimate composition of the repair tissue is
usually a hybrid of hyaline and nbrocartilage.
4. Operative repair of damaged articular cartilage rarely
reproduces the original structure. This failure results from
the relative avascularity of articular cartilage and a paucity
of cells available to provide the necessary materials. A lack
of blood vessels disrupts the normal connective tissue
response to injury: haemorrhage, fibrin clot formation,
inflammatory reaction, phagocytosis and the synthesis of
extracellular matrix components. Hyaline cartilage is
uniquely composed of predominantly type II collagen and
large cartilaginous macromolecules. The pluripotent (Latin
pluris = several + potentia = power), undifferentiated cells
available for repair do not consistently metamorphose into
mature cells capable of replacing these elements.
5. When treating fractures involving an intra-articular
element, aim to reduce the joint surfaces as anatomically
as possible and stabilize the fragments to minimize steps
and gaps that will cause later degeneration of the joint.
6. Osteoarthritis is a condition affecting predominantly
the articular cartilage. The severity of the wear is classi-
fied accordingly:
Grade I: Softening of the articular cartilage
Grade II: Fibrillation and fissuring of articular cartilage
Grade III: Partial thickness cartilage loss, clefts and
chondral flaps
Grade IV: Full thickness cartilage loss with exposed bone
Once the articular cartilage surface is breeched, the
hyaline structure rapidly deteriorates. There is a loss of
the proteoglycan and collagen in the matrix. The damaged
cartilage breaks up and becomes free within the joint. It is
regarded as irritant to the articulation and induces a syno-
vitis as the lining attempts to phagocytose the fragments.
NERVOUS TISSUE
1. The organization of peripheral nerves is well
described. An individual nerve fibre is separated from
others by a loose connective tissue network, known as
endoneurium. Some nerve fibres are enveloped by myelin
(Greek myelos - marrow).
2. A group of nerve fibres form a fascicle, defined by a
circumferential layer of perineurium. A group of fascicles
forms an individual nerve. The fascicles are separated by
epineurium, which is condensed to form a sheath around
the whole nerve.
3. The blood supply to a nerve has both intrinsic and
extrinsic components. Within the nerve are vascular
plexuses at epineurium, perineurium and endoneurium
levels. Externally, blood reaches the nerve at intervals
from segmental regional vessels, which run in the con-
nective tissue around the nerves. There are longitudinal
anastomoses between the different supplying vessels,
ensuring a rich microvascular network to support the
metabolic activity of the nerve.
4. The environment of the individual nerve fibres is
regulated and protected by the physical diffusion barrier
of the perineurium and the structural and functional char-
acteristics of the endoneurial capillaries, which function
as a blood-nerve barrier similar to the blood-brain
barrier in the central nervous system. Injury can affect
these barriers and affect nerve function.
5. When mobilizing a nerve, as in ulnar nerve trans-
position, handle it and its surrounding tissue as little as
possible to avoid damaging the nerve and its supplying
vessels. Avoid tension and unnecessary dissection to
minimize interruption of the longitudinal anastomoses.
Avoid compressing the nerve (Fig. 33.5).
Nerve injuries are classified in a number of different
ways. In 1951, injuries were classified into five degrees
(Table 33.2).
6. Nerves can be damaged by undue traction during
surgery. Depending upon the force of stretching and the
duration of the insult, the nerve may suffer any injury
between the first and fifth degrees.
Key point
• Ensure that you revise the anatomy of
neurological structures before, not during,
operation.
7. Certain approaches are associated with particularly
high rates of inadvertent nerve damage, such as the ulnar
nerve at the elbow and radial nerve at mid-humeral level.
At the beginning of the procedure, identify, appropriately
mobilize and preserve the 'nerve(s) at risk'. Exercise par-
ticular care when undertaking procedures through previ-
ously explored areas, as the nerve position may have
changed and identification is more difficult in dense scar
tissue.
340
RESPONSES OF CONNECTIVE TISSUE AND BONE
33
Fig. 33.5 Protective effects of the epineurium when a nerve is subjected to mechanical trauma. Several small fascicles
embedded in a large amount of epineurium (left) are less vulnerable to transection injuries and compression than
large fascicles in a small amount of epineurium (right).
8. Nerve damage at sites distant from the operative
area may be caused during operation. Ensure that vul-
nerable nerves are suitably protected when positioning
the patient before operation, particularly the radial nerve
in the arm and the common peroneal nerve in the leg.
r^
Key point
Beware prolonged inflation, and overinflation,
of tourniquets.
Table 33,2 Nerve injury classification
Degree
II
IV
V
Description
Conduction block
Lesion confined to the axon. Wallerian degeneration occurs
within an intact endoneural sheath
Both the axon and endoneurium lose continuity within an
intact perineurium
Loss of the perineurium around the fascicles. Only the
epineurium remains to provide continuity
Complete loss of division of the nerve
Previous classification (1943)
Neurapraxia
Axontmesis
Neurotmesis
341
POSTOPERATIVE
9. If you inflate a tourniquet much beyond the patient's
systolic pressure, the cuff may deform and damage
peripheral nerves beneath it. The effects are mediated by
mechanical pressure and ischaemic change. Mechanical
compression causes obstruction of intraneural blood
vessels and ischaemia causes damage to the same vessels,
affecting permeability and leading to intraneural oedema.
To minimize the effects of tourniquet ischaemia on nerve
and muscle, make sure the pressure in upper limb tourni-
quets is no more than 50-100 mmHg above systolic pres-
sure and no more than double systolic pressure in the leg.
Do not exceed 2 h maximum tourniquet pressure.
10. When planning surgical incisions, take into account
the concept of 'internervous planes'. Consider the skin
areas and muscles supplied by individual peripheral
nerves. When possible, incise between the 'territories' of
major nerves. For instance, Henry's approach to the volar
(palmar) aspect of the forearm is placed between brachio-
radialis muscle, supplied by the radial nerve, and flexor
carpi radialis, innervated by the median nerve.
11. Neurological structures are clearly in danger of
thermal injury from injudicious use of diathermy close to
nerves. In such situations, use bipolar diathermy
12. The outcome following nerve repair depends
heavily upon surgical technique and operator experi-
ence. Prepare the nerve ends carefully, appose and
realign individual fascicles, and leave a small gap
between the ends, with minimal tension, to achieve the
best results.
mechanisms triggered by an intact sensory system.
Frequently, the situation is exacerbated by a concomitant
arteriopathy. As a result, diabetics are more prone to the
development of ulcers, deep sepsis (including osteomyeli-
tis), delayed wound healing postoperatively, and Charcot
joints (after repetitive trauma).
GAIT
: : ^>#$&^*^^^
fi^^^^^,^ m ^;^t^i'i?%^^ ! :
1 . Normal gait (Old Norse gat = way, path; a way of
walking, pattern of leg movements) is extremely complex.
It requires equilibrium, the ability to stand upright in
balance, and also to initiate locomotion (Latin locus =
place + mover e = to move). In order to achieve both of
these requirements, the skeletal, muscular, sensory and
motor nervous systems must work in concordance.
2. Different people walk in a wide variety of ways,
depending upon the body shape and weight, urgency of
moving, and other factors. The variation is so great that it
is often possible to identify a close companion at a dis-
tance by recognizing the gait.
3. Carefully observe the gait of people and identify the
stages of the cycle (Fig. 33.6).
4. You should be able to describe the main stages of the
normal walking pattern.
5. Patients may limp (Old English lemp-healt = halting)
for several reasons. The Latin word is claudus, and the
Emperor Claudius was so named because he was lame.
The main causes are listed in Table 33.3.
0mm
Key point
• If there is a neuropathy, always consider
diabetes.
13. Diabetes is frequently affected by neuropathy.
Musculoskeletal tissue, especially in the_extremities, can
be prone to trauma because of loss of normal protective
BONE
1 . Bone forms the skeleton (Greek skellein = dry; origi-
nally + soma = body; dried body), a supporting structure.
It is a highly vascular hard tissue with the capacity to
grow in width (accretion, as a tree trunk expands) and
length by endochondral ossification. The body is com-
posed of flat bones and long bones. The long bones have
Table 33,3 Major causes of limp
Cause
Example
Pain: antalgic (Greek znti = against + afgos = pain;
Arthritis of a joint, fracture, ligament injury
pain relieving) gait
Weakness: paresis (Greek parienai = to relax;
Gluteal muscle weakness (= Trendelenburg gait);
diminished function) or paralysis
neurological injury
Leg length discrepancy
Congenital deformity; post-traumatic
Stiffness
Arthritis of a joint
Post-traumatic soft tissue swelling
342
RESPONSES OF CONNECTIVE TISSUE AND BONE
33
Double limb
support
Single limb
support
Double limb
support
Heel
strke
Opp.
toe
Heel
oft
Opp. heel
strike
Opposite angle
limb support
I
Toe
off
Heel
strike
10%
1 5%
30%
30%
50% 60%
Percent of walk cycle
55% 60%
100%
100%
Stance phase - 60% of cycle
Critical
event
Heel
strike
Foot
flal
Swing phase - 40% of cycle
Knee Toe
bend off
Toe clearance
Heel
strike
Fig. 33.6 Phases and events of walking cycle. Stance phase constitutes approximately 62% and swing phase 38% of
cycle.
a central tubular structure, the diaphysis (Greek dia =
through + physis = nature, growth), and an expanded end,
the metaphysis (Greek meta = after), which incorporates
the growth plate, the physis, and the subchondral bone
plate covered by the articular cartilage of the adjacent
joint. At skeletal maturity the architecture of the metaph-
ysis becomes homogeneous, with loss of the cartilaginous
growth plate. Bone is largely composed of type I collagen.
It contains cells (osteocytes) embedded in an amorphous,
fibrous collagen matrix interspersed with calcium phos-
phate, an inorganic bone salt. Osteoporosis is character-
ized by a reduction in bone mass. Loss of structural
strength may lead to fracture and also affects implant
fixation.
2. Bone exists in two forms, depending on the arrange-
ment of the collagen fibre and the osteocytes. Immature
bone has fibres and osteocytes irregularly arranged. The
osteomucin is basophilic and there is a sparsity of
calcium. It forms, during development of differentiating
mesenchyme, into the bones of the skull vault, mandible
and clavicle, and when bone is laid down in differenti-
ating mesenchyme, as in fracture healing. It also occurs in
various bone diseases, including osteogenic tumours.
Adult bone has the collagen arranged in parallel sheets
or bundles, as flat plates or, in long bones, as tubular
vascular canals surrounded by concentric systems of
cortical bone, described in 1689 by the English physician
Clopton Havers (1650-1702). The bone is less compact in
the central canal of long bones and is termed cancellous
(Latin cancellus = lattice; porous). Most of the skeleton is
formed on a cartilagenous model from ossification
centres in the diaphysis and epiphyses (Greek epi -
upon) which spread in all directions, replacing cartilage
with bone. During growth, the cartilagenous physis
grows as it is invaded from both sides, so the bone con-
tinues to lengthen. At the interface between expanding
ossification and the cartilage, osteoblasts, resembling
fibroblasts, lay down collagen and osseomucin, which
becomes osteoid, which immediately becomes calcified
with calcium phosphate deposition. This interferes with
cartilagenous nutrition so the chondrocytes die, being
replaced by osteocytes, the mature osteoblasts, which
are locked in the newly created bone. At maturity the
cartilagenous physis plate is invaded from both sides,
which eventually fuse across it, so further growth in
length ceases. A similar process occurs during the
healing of bony fractures. Adult bone replaces mem-
brane bone so that the whole skeleton of adults is
composed of it.
3. There may be varied stimuli for changes in bone,
including fatigue damage, stress-generated potentials,
changes in the hydrostatic pressure of the extracellular
fluid, and changes in the cell membrane diffusion
resulting from direct loading. In 1892 the German-born
orthopaedic surgeon Julius Wolff stated that if bone is
mechanically stressed it is stimulated to build up bone in
response to the force. It is considered likely that stretch
receptors are associated with ion channels on osteocytes.
343
3
POSTOPERATIVE
A minimum level of repetitive load is necessary to
maintain normal bone. A number of biochemical changes
can be detected during the process including raised
prostacyclin, prostaglandin E2, intracellular enzyme
glucose-6-phosphate dehydrogenase (G6PD), nitrous
oxide (NO) and growth factors, including insulin-like
growth factor 1 (IGF-1), which is a mediator of metabolic
activity. Bone remodelling is accomplished by large
multinucleate osteoclasts (Greek clasis = a breaking),
which absorb bone, creating spaces or lacunae, described
in 1841 by the London surgeon John Howship; osteo-
blasts lay down bone elsewhere. Cancellous bone has
more extensive surfaces than cortical bone so it is more
responsive to stimuli. Advances in imaging, combined
with high-speed digital computers, have permitted
analysis of the mechanical stresses to the level of
individual trabeculae within bone. Bones carry electrical
potentials at rest, resulting from metabolic processes.
Active growth plates are electronegative. If bones are
loaded to bend them, a negative charge develops on the
compressed side and a positive charge is generated on
the distracted side. Bone deposition occurs on the
negative compressed side, and resorption on the
positively charged distracted side. The electrical changes
were thought to be the result of a piezo- electric {Greek
piezein = to press) effect - compression of a crystalline
structure generating an electrical charge. This mechan-
ism has been challenged. Bone behaves as a composite
viscoelastic material (Latin viscosus = sticky). It has
multiple channels and lacunae within it, the lining of
which may have a charge. Ions in the fluid within the
channels tend to stay in the vicinity of the ions in the
lining which carry an opposite charge. If the fluid flows,
as a result of bone deformation, the ions are separated,
resulting in an electrical field and a potential difference.
This is called a streaming potential. The alternative
explanation to a piezoelectrical effect is that when the
bond is strained, movement of the non-mineralized
matrix produces fluid movement, resulting in streaming
potential which sensitizes the osteocytes and osteoclasts
(Greek klasis - fracture; hence, absorption). The osteo-
cytes respond by laying down bone and the osteoclasts
by absorbing bone; the result is a remodelling to adapt
the bone structure to any change in the forces exerted on
it. In the hope of exploiting this mechanism, direct
current, capacitative coupling, and pulsed electro-
magnetic fields have been used to stimulate osteogenesis
in fractures and osteoporosis.
4. Bones and soft tissue respond to the loads placed
upon them. Regular exercise has been shown to improve
muscle strength and endurance and has important,
although less obvious, ramifications for the structure and
function of bone. This is particularly important for the
elderly in an attempt to partially offset the development
of osteoporosis. Bone conforms to Wolff's law. Julius
Wolff was a German scientist, who in the late 1800s, stated
that 'every change in the form and function of bones or of
their function alone is followed by certain definite
changes in their configuration in accordance with mathe-
matical laws' — to borrow a modern sporting phrase 'use
it or lose it!'. Increasing the load upon a bone increases the
overall bone mass and causes remodelling of the bone to
best withstand the types and directions of stress placed
upon it. In normal long bones, the bone is strongest in
resisting compressional forces, weakest in shear and
intermediate in tension.
5. In osteoarthritis, the subchondral bone reacts to the
loss of cushioning from the progressively diminishing
articular cartilage. The bone becomes thicker and radio-
logically denser as a result of the loss of its 'stress
shielder'. Eventually, the bone decreases in height as a
result of successive trabecular fractures. Witness the
increased work required to resect the medial femoral
condyle compared to the lateral side during knee replace-
ment surgery for a varus osteoarthritic joint.
6. The bone is continually repairing small defects
developing within it. Usually, that process takes place
before more major fractures occur. However, in impaired
bone or bone subjected to higher than normal forces,
fractures may occur. Patients who inhale nicotine, take
catabolic steroids, or regular long-term non-steroidal
anti-inflammatory medication, represent common groups
with impaired ability to heal bone under various circum-
stances. The beneficial effect of postsurgery rehabilita-
tion, with early weight-bearing and joint mobilization, is
clear.
7. Certain conditions can lead to markedly increased
density of bone. Sickle cell anaemia causes bone to
undergo repeated infarcts as a result of vascular insults.
The medullary cavity of long bones can be converted
from a lattice- work pattern to an ivory-dense bone mass.
Be aware of this or you can experience considerable
problems in breaching such bone, as when placing an
intramedullary implant.
8. Surgical operations to bone may be required for
many reasons. The most common indication is to facilitate
fracture healing. Bone may need to be divided to realign
it, an osteotomy. Bone biopsy is carried out to obtain
specimens to determine suspicious pathology. Bone may
require resection because of infection or neoplasia. An
increasingly common reason for operations is to replace
worn articulations with prosthetic implants.
9. Healing of bone may be stimulated in a number of
ways, including the use of demineralized bone matrix
harvested from donor bones. Electrical stimulation has
been in use since the 1880s. It is now known that when a
bone breaks it generates a low-level electrical field, which
stimulates repair.
344
RESPONSES OF CONNECTIVE TISSUE AND BONE
33
MMMIM^,.
Osteoporosis and osteomalacia
Distinguish between osteoporosis (Greek poros = a
passage; permeable) and osteomalacia (Greek malakos =
soft) in terms of the way the bone responds (Fig. 33.7). In
both pathological conditions the bone is less able to with-
stand repetitive stresses or abnormal loads. As a result,
such patients are more liable to develop pathological
fractures and are at increased risk of developing peri-
operative injury.
Neoplastic bone lesions
1. Bone can be affected by primary and secondary
tumours. In primary lesions, a number of different cells of
origin can be implicated, such as osteoblasts in osteogenic
sarcoma and chondrocytes in chondrosarcoma.
2. Some tumours are osteosclerotic, with increased
bone formation, for example, prostatic secondaries, but
the majority are osteolytic. Whatever the pattern, the bone
involved with such lesions is abnormal and does not
follow predictable biomechanical patterns when placed
Normal bone
Osteoporosis
Osteomalacia
Normal volume and
mineralization ot bone
^
Bone present is
normally mineralized
but of reduced volume
Normal volume of
bone, but bone
present has
reduced amount
of mineralization
Key
Mineralized bone
Unmineralized bone
Fig. 33.7 The volume of bone is represented by the
total number of boxes. The amount of mineralized bone
is represented by the dark shaded boxes.
under stress. As a result, the patient experiences pain and
potential fracture at the point of weakness.
3. Repeated imaging can monitor the progress of such
lesions, and the healing response following such treat-
ment as radiotherapy. However, there are certain param-
eters which gauge the potential for impending fracture
and provide information about the desirability of pro-
phylactic surgical intervention:
a. Long bone lesion greater than 2,5 cm increases the
risk.
b. Lytic destruction of more than 50% of the bone's
circumference has a greater than 50% risk of fracture.
c. Persistent pain on weight-bearing despite radiother-
apy treatment is an ominous signal of impending fracture.
Periosteum
1 . This is a thin lining tissue which surrounds the bone.
It consists of two layers when examined histologically, an
outer layer and an inner cambial layer (Latin cambium, is
the exchange layer between the bark and wood of trees),
although the layers cannot be separated macroscopically.
It is easily peeled off the bone except at the juxta-
articular region, where it is densely adherent at the point
of attachment of the joint capsule, and at the insertion of
muscles and tendons. For example, the insertion of the
patellar tendon into the tibial tuberosity requires sharp
dissection. In childhood, the periosteum is thick but it
becomes thin with age.
2. Periosteum is relatively inelastic and is therefore dif-
ficult to suture and repair. It has a rich blood supply, often
with prominent blood vessels on its surface, so that it
bleeds readily when incised.
3. Periosteum is the most important structure involved
in bone repair, so protect it. When performing an
osteotomy it may be incised by cutting hard down onto
the bone with a scalpel, elevating it to separate it from the
bone, followed by formal bony division, or it can be per-
forated at intervals using a drill or fine osteotome (Greek
osteon - bone + temnein = to cut) as part of a percutaneous
osteotomy.
4. Occasionally it is released circumferentially in an
attempt to accelerate growth in children. It is also
elevated and separated from underlying bone in infection
and in neurological conditions such as spina bifida - a
congenital cleft of the vertebral column with meningeal
protrusion.
Bone blood supply
1. The blood supply to long bones is well defined,
coming from both endosteal (within the bone) and
periosteal (around the bone) surfaces. Normal blood flow
is centrifugal, vessels running distally away from the
345
33 * :
POSTOPERATIVE
heart. The bone receives most of its blood supply from
medullary vessels,
2. Fracture disrupts the blood supply and revascular-
ization occurs from the periosteum and surrounding soft
tissues. In the early stages of repair, blood flow is pre-
dominantly centripetal (Latin petere = to seek; flowing
proximally).
3. There are three primary components of the blood
supply in long bones: the nutrient artery, metaphyseal
arteries and periosteal arterioles. The diaphyseal supply
is from the nutrient artery, which divides into ascending
and descending medullary arteries supplying the major-
ity of the diaphyseal cortex. The metaphysis is supplied
by a rich network of metaphyseal arteries. It is much
more vascular than the diaphysis and this is reflected
in its ability to undergo repair following a fracture or
osteotomy. The periosteal arterioles supply the outer
third of the diaphyseal cortex in a patchy manner and
anastomose with terminal branches of the medullary
arteries.
4. The efferent vascular drainage is through large
emissary veins and venae comitantes of the nutrient
artery, which drain the medullary contents almost exclus-
ively, whereas the cortex drains through cortical venous
channels into periosteal venules.
5. In flat bones the blood supply is closely reflected in
its periosteal attachments and is therefore tenuous in the
navicular and scaphoid bones, which are at risk from
avascular necrosis following fracture and dislocation.
Also at risk is the head of the femur following femoral
neck fracture, as it receives one-fifth of its blood supply
through the ligamentum teres.
In children, haematogenous spread of osteomyelitis
may occur to the joint if there is an intracapsular
physis.
6. Under certain circumstances, the vascularity of bone
may be increased, with an effect upon surgical proce-
dures. In Paget's disease, described in 1877 by the
London surgeon Sir James Paget (1814-1899), the
increased metabolic activity induced by osteoclastic and
osteoblastic activity necessitates an increased blood
supply and may induce a high-output cardiac failure in
the patient. The increased activity renders the bone more
brittle and more liable to fracture following injury or
during operation.
Certain tumours are associated with an increased blood
supply. A common example that of metastatic lesions to
bone from renal cell carcinoma. The leash of vessels
around the deposit can cause profuse bleeding during
surgical procedures.
In osteoarthritis, much of the pain is thought to be
derived from the altered subchondral bone, with its
hypervascularity and venous stasis.
Natural bone healing
1. Following fracture or osteotomy, bone enters a repair
cycle of overlapping processes involving inflammation,
haematoma formation, development of granulation
tissue, callus formation and remodelling. Healing is influ-
enced by the amount of damage, and therefore the local
tissues available for repair. Callus (Latin = hard) is woven
bone, cartilage, or a mixture of the two.
2. Primary callus response develops following a frac-
ture and is initiated from the bone itself. It is short lived,
lasting a few days to weeks, and sustained by bone
contact. The second process is that of bridging external
callus, which is a rapid process, tolerant of fracture move-
ment and dependent on recruitment from the surround-
ing soft tissues. A third response, in which fibrous tissue
is replaced by bone, is seen within the medulla. It is
relatively independent of movement and is termed late
medullary callus. The response depends on the amount of
motion at the fracture site (interfragmentary strain).
3. If movement is obliterated, following, for example,
rigid plate fixation, a different form of healing occurs,
without intermediate callus formation. This is known as
primary cortical healing. In most cases fixation reduces
but does not entirely abolish strain, leading to the con-
version of bridging fibrous tissue into cartilage, and, as
the strain diminishes, bone is laid down. If tissue viabil-
ity is poor, if there is excessive motion, a fracture gap, or
if infection supervenes, healing is impaired.
Implants
Plates
1. Plate fixation involves extensive dissection of the
soft tissues, with incision and elevation of the peri-
osteum. The fracture site is exposed, the haematoma is
evacuated and the periosteal circulation of the bone is
interrupted. Preservation of the haematoma may be
valuable, although whether the haematoma provides
cellular elements contributing to fracture healing is
controversial.
2. Following fracture or osteotomy, blood flow
becomes centripetal and the periosteal circulation
becomes dominant, primarily through dense connective
tissue attachments. A plate reduces the local cortical blood
supply. Blood perfusion is reduced by the close plate-to-
bone contact because of periosteal damage and, by
drilling through the bone for bicortical screw anchorage,
both endosteal and intramedullary damage.
3. Rigid plate fixation eliminates micromotion at the
fracture site, facilitating primary cortical healing.
Terminal bone death is minimized and union occurs
slowly, mainly by creeping cortical substitution. The plate
346
RESPONSES OF CONNECTIVE TISSUE AND BONE
33
reduces stress on the bone and so may lead to bone
atrophy, with the risk of refracture following plate
removal. New low-contact compression plates inserted
with minimal access may reduce the effects.
Intramedullary nails
1. A nail can be inserted without disturbing the frac-
ture site or fracture haematoma. High intramedullary
pressures may be induced while inserting the awl, guide
rod and reamers and they may produce local damage and
embolization. The nail is inserted down the length of the
medullary canal, providing stability through areas of
endosteal contact and also by the insertion of locking
screws that pass through both cortices. Intramedullary
nails permit more fracture motion than do compression
plates, although nails vary significantly in their resistance
to torsion (twisting) and to bending.
2. Reaming (Old English ryman = to open up) may be
used to allow larger diameter nails to be inserted, increas-
ing the contact area between the nail and the internal
surface of the bone; however, although this benefits frac-
ture stability, it can weaken the bone. Rigid nails provid-
ing stress protection may prejudice full recovery of
strength.
3. Cortical reaming and nail insertion both injure the
medullary vascular system, resulting in avascularity of
significant portions of the diaphyseal cortex; nails
inserted without preparatory reaming show more rapid
revascularization.
4. Healing is more rapid than with plates, and refrac-
ture is rare. The limb reacts to medullary damage by
exhibiting a significantly raised extraosseous blood
supply. Primary callus response and bridging external
callus both occur but medullary healing is inhibited.
Reliability and speed of healing are both affected by frac-
ture motion.
5. In animal studies the blood flow at the fracture site
and within the whole bone was higher when using nails
compared with plates, and it remained elevated for a long
period.
External fixation
1. This can be applied without invading the fracture
area. Unilateral fixators are applied with large, 5-6 mm
diameter screws across the medullary canal, possibly tem-
porarily disrupting the medullary blood flow. The bone is
supported more effectively on the near cortex, referred to
as 'cantilever loading'. Bridging external callus is seen
more readily on the far cortex.
2. Dynamization (permitting movement within the
body of the fixator within 3-6 weeks of injury) reduces
the amount of fracture movement and allows slight frac-
ture collapse, resulting in reduced pin site stresses and
more rapid healing. Micromotion may speed up healing
rates.
3. Fine-wire circular fixators are believed to produce
less interference with the blood supply because the wires
are only 1.5-2 mm in diameter. They provide an entirely
different mechanical environment compared to unilateral
fixators, with relatively even support for the whole bone
('beam loading'), permitting more fracture motion.
Unusually, as the limb is loaded the fixator becomes
stiffer, hence supporting high activity levels while con-
trolling fracture motion. Rapid healing rates with little
visible callus may be seen, perhaps reflecting a rapid
medullary response unique to this device.
Osteotomy
1. There is complete transection of the bone; studies in
dogs have shown a 50% decrease in blood flow at 10 min
and 66% at 4 h. Following double osteotomy in the dog
tibia, 80% of the intermediate fragment had vessels in the
haversian canals that were derived from the endosteal cir-
culation. Both the intermediate fragment and the bone
ends showed bone resorption and new bone formation in
the haversian systems.
2. In order to spare the tissues, corticotomy, a low-
energy osteotomy of the cortex, preserving the local
blood supply to both periosteum and medullary canal,
may be used. In open corticotomy the periosteal struc-
ture is preserved. Preservation of the periosteum and
intramedullary vessels are both important in the forma-
tion of new bone.
Distraction
1. Controlled mechanical bone distraction after
osteotomy can produce unlimited quantities of living
bone and direct the new bone formation in any plane fol-
lowing the vector of applied force. The new bone sponta-
neously bridges the gap and rapidly remodels to the
normal macrostructure of the local bone.
2. Within the distraction regenerate three zones can be
recognized, according to morphology and the calcium
content. They are a fibrous interzone, a primary mineral-
ization front and a new bone formation zone. Other con-
nective tissues and skin respond to the distraction
process; the pioneer Russian surgeon Gavril Ilizarov
(1921-1992), working in Kurgan, Siberia, described the
Law of Tension Stress: gradual traction on living tissues.
As ossification occurs in the callus between the bone ends,
if the bone ends are carefully and slowly distracted the
callus is extended in a similar manner to growth of a
physis during normal bone growth. In consequence the
bone lengthens.
347
3
POSTOPERATIVE
3. Taw of tension stress' - gradual traction on certain
living tissues creates stresses that can stimulate and main-
tain the regeneration of active growth. Slow, steady trac-
tion of tissues causes them to become metabolically
activated, resulting in an increase in their proliferative
and biosynthetic functions.
Bone cement
1 . Polymethylmethacrylate (PMMA) has been used as
a self-curing grout (filler) for implants since the
Manchester orthopaedic surgeon Sir John Charnley
(1911-1982) began replacing hips in the 1960s. Mixing the
powder and liquid components induces polymerization.
This is an exothermic (Greek ex = out + therme = heat)
reaction generating significant heating of local tissue
and the potential for bone necrosis. This has been exten-
sively researched as a possible cause of later implant
loosening.
2. Orthopaedic surgeons are aware of the potential for
cardiovascular collapse following the insertion of PMMA,
especially into the femoral canal. It seems likely that the
resulting elevated pressures (up to 900 mmHg) within the
canal force fat and marrow contents from the bone into
the circulation. These elements reach the pulmonary
circulation within 2 min, initiating the aggregation of
platelets and other clotting elements.
Key point
Cardiovascular collapse can be partially
prevented by ensuring the patient is well
hydrated before inserting bone cement.
Summary
• Have you appreciated how dynamic are
the connective tissues, including bone?
• Do you have a basic understanding of the
responses of bone and connective tissues
to trauma?
Can you name some of the factors that
modify the strength and growth of
connective tissues, and how they act?
Are you able to name some redundancies
that function in spite of injury or disease?
Do you appreciate the importance of
preserving and restoring function resulting
from injury and disease?
Reference
Henry AK 1945 Extensile exposure applied to limb surgery.
Livingstone, Edinburgh, p 101
Further reading
Aronson ], Good B, Stewart C, Harrison B, Harp JH 1990
Preliminary studies of mineralization during distraction
osteogenesis. Clinical Orthopaedics 250: 43-49
Bolander ME 1994 Regulation of fracture repair and synthesis of
matrix molecules. In: Brighton CT, Friedlander G, Love JM
(eds) Bone formation and repair. American Academy of
Orthopedic Surgeons, Rosemont, pp 186-187
McKibbin B 1978 The biology of fracture healing in long bones.
Journal of Bone and Joint Surgery 60B: 150-162
O'Sullivan ME, Chao EYS, Kelly PJ 1989 The effects of fixation
on fracture healing. Journal of Bone and Joint Surgery
71 A: 306-310
Rhinelander FW 1968 The normal microcirculation of
diaphyseal cortex and its response to fracture. Journal of
Bone and Joint Surgery 50A: 784-800
Rhinelander FW 1974 The normal circulation of bone and its
response to surgical intervention. Journal of Biomedical
Materials Research 8: 87-90
Smith SR, Bronk JT, Kelly PJ 1990 Effect of fracture fixation on
cortical bone blood flow. Journal of Orthopeadic Research
8: 47M78
Yang L, Nayagam S, Saleh M 2003 Stiffness characteristics and
interfragmentary displacements with different hybrid
external fixators. Clinical Biomechanics 18: 166-172
348
Postoperative care
J. J. T. Tate
W
Objectives
Understand the principles of patient
management in the recovery phase
immediately after surgery.
Understand the general management of
the surgical patient on the ward.
Consider the initial management of
common acute complications during the
postoperative period.
INTRODUCTION
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Postoperative care of the surgical patient has three
phases:
1 . Immediate postoperative care (the recovery phase)
2. Care on the ward until discharge from hospital
3. Continuing care after discharge (e.g. stoma care,
physiotherapy, surveillance).
The intensity of postoperative monitoring depends upon
the type of surgery performed and the severity of the
patient's condition.
THEREODVE^
Basic management
Immediately after surgery patients require close monitor-
ing, usually by one nurse per patient, in a dedicated
recovery ward or area adjacent to the theatre. Monitoring
of airway breathing and circulation is the main priority
but a smooth recovery can only be achieved if pain and
anxiety are relieved; monitoring the patient's overall
comfort is essential. The nature of the surgery will deter-
mine the intensity of monitoring and any special precau-
tions, but children, the elderly patients with coexisting
medical disease and patients who have had major surgery
all require special care.
Management of the general comfort of the patient
includes:
• Relief of pain and anxiety
• Administering mouthwashes (a dry mouth is common
after general anaesthesia)
• The patient's position, including care of pressure points
• Prophylactic measures against:
- atelectasis by encouraging deep breathing
- venous stasis by passive leg exercises.
These steps, including the prophylactic measures, all
start in the recovery area and will continue on the main
ward.
Airway and breathing
Patients may have an oral airway, a nasopharyngeal
airway or, occasionally, may still be intubated on arrival
in recovery; all secretions must be cleared by suction and
the artificial airway left until the patient can maintain his
or her own airway. Breathing may be depressed and a
patient hypoxic due to three factors:
• Airway obstruction
• Residual anaesthetic gases
• The depressant effects of opioids.
Oxygen is given, ideally by mask, and the oxygen satu-
ration monitored by a pulse oximeter. Special care is
needed for patients with a new tracheostomy If there is
concern about vomiting and the risk of aspiration,
patients can be sat up or nursed head-up rather than
supine.
Circulation
Blood pressure is recorded quarter-hourly or, after major
surgery, continuously via a radial artery cannula. The
pulse rate is recorded regularly and continuously moni-
tored by a pulse oximeter. The wound and any drains are
monitored for signs of reactionary bleeding.
349
34
POSTOPERATIVE
Fluid balance
Before patients are returned to the ward their calculated
fluid losses should be replaced with blood, blood prod-
ucts or crystalloids, and, ideally, fluid balance achieved.
Monitoring of central venous pressure (CVP) can assist
fluid balance management in severely ill patients or after
major surgery. Urine output measurement may also
provide useful information.
Core temperature
The patient's temperature is monitored, as there may be
a significant drop during surgery, which should be cor-
rected before the patient leaves the recovery room (e.g.
with a space blanket). As the temperature rises, periph-
eral vasodilatation may occur; if not anticipated this can
lead to hypotension after the patient has returned to the
ward.
Special factors
Specific medical conditions and certain types of surgery
will require additional monitoring. Some examples are:
• Diabetes mellitus - blood sugar monitoring
• Cardiac disease - electrocardiogram (ECG) monitor
• Orthopaedic surgery - monitoring of distal perfusion
in a treated limb, position of limb, maintenance of
fracture reduction, examination for peripheral nerve
injury
• Neurosurgery - quarter-hourly neurological observa-
tions, intracranial pressure monitoring (intraventricu-
lar catheter or a transducer in the subarachnoid space)
• Urology - catheter output (after transurethral prostatec-
tomy bladder irrigation is usually implemented and
pulmonary oedema can develop if glycine has been
absorbed into the circulation; fluid balance is particu-
larly important)
• Vascular surgery - distal limb perfusion.
Pulse oximeter versus arterial blood gas
The pulse oximeter is an essential piece of equipment for
the management of the postoperative patient. It moni-
tors three parameters: pulse rate, pulse volume and
oxygen saturation. The fingertip sensor contains two
light-emitting diodes (LEDs): one red, measuring the
amount of oxygenated haemoglobin, the other infrared,
measuring the total amount of haemoglobin. The actual
amount of oxygen carried in the blood relative to the
maximum possible amount is computed - this is
the oxygen saturation (Sao 2 ). The delivery of oxygen to
the tissues depends on:
• Cardiac output
• Haemoglobin concentration
• Oxygen saturation (Sao 2 ).
The relationship between oxygen in the blood and Sao 2 is
linear and thus easy to interpret. A fall in oxygen reach-
ing the tissues can be detected far more rapidly with Sao 2
monitoring than by clinical observation of the lips,
nailbeds or mucous membranes for cyanosis (which may
only be apparent when the Sao 2 is 60-70%) or by measur-
ing arterial blood gases. It should be noted that pulse
oximetry does not indicate adequate ventilation; the Sao 2
can be normal due to a high inspired oxygen level.
Blood gases
Arterial blood gases measure pH, arterial oxygen and
carbon dioxide tensions (Pao 2 , Paco 2 ), bicarbonate and
base excess. These measurements are affected by many
variables and can be difficult to interpret. The Pao 2 has a
non-linear relationship to the oxygen content of the blood
(the oxygen dissociation curve), and hence oxygen satur-
ation is easier to use in practice.
Paco 2 reflects the rate of excretion of carbon dioxide by
the lungs and is inversely proportional to the ventilation
(assuming constant production of carbon dioxide by the
body). The base excess and bicarbonate reflect acid-base
disturbances and may be used in conjunction with the
Paco 2 to distinguish respiratory from metabolic problems.
r^
The recovery phase
Management of pain and anxiety is as important
as care of airway, breathing and circulation.
Restoring body temperature is important for
prevention of circulation and clotting problems.
Sao 2 (pulse oximeter) has a linear relationship
to the amount of oxygen in the blood, giving a
sensitive indication of tissue oxygenation.
CARE ON THE WARD
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Patients may be discharged from the recovery area when
they are able to maintain their vital functions indepen-
dently (i.e. full consciousness and stable respiratory and
cardiovascular observations).
On the ward, the aim is to maintain a stable general
condition and detect any complications early. Initially,
closer and more frequent observation is necessary and the
priorities are the same as in the recovery room. Nursing
350
POSTOPERATIVE CARE
34
staff perform routine observations; medical staff must
undertake additional, clinical monitoring dictated by the
nature of the case, including daily review of drug pre-
scriptions (Table 34.1).
General care
General care includes those measures described pre-
viously and control of pain. Early ambulation can reduce
the risk of thrombotic complications. Patients who cannot
mobilize require particular attention to skin care and
pressure areas. Appropriate explanation of the results of
the operation and the expected postoperative course
should be given to the patient and relatives. The nature of
the surgery or underlying disease will determine ad-
ditional specific management (e.g. physiotherapy after
orthopaedic surgery, stoma care for a new stoma).
Pain control
It is impossible for a patient to make a smooth recovery
from surgery without adequate pain control (see Ch. 35).
There has been a general shift from intermittent intra-
muscular analgesia to intravenous analgesia, either by
continuous infusion or patient-controlled bolus, or epi-
dural analgesia after major surgery. An epidural is
particularly useful after major abdominal surgery, but
insertion of an epidural catheter in patients who have
received a preoperative dose of heparin for deep vein
thrombosis prophylaxis is controversial and contraindi-
cated if the patient has a coagulopathy.
For day surgery or minor operations oral analgesia is
suitable and is most effective when prescribed regularly
Narcotics can still be used if required. Non-steroidal anti-
inflammatory drugs (NSAIDs) are popular but must be
avoided in some patients, including asthmatics and those
with a history of peptic ulcer or indigestion. Rectal
administration of NSAIDs to a sedated patient should
only be given with preoperative consent.
Fluid balance
Fluid balance is important after major surgery and easier
if a urinary catheter is in situ, allowing accurate charting
of urine output. Visible fluid losses are recorded on a fluid
balance chart at regular intervals (e.g. hourly for urine
output, 4-hourly for nasogastric aspirations, and 12- or
24-hourly for output into drains) and totalled every 24 h.
Unrecorded fluid losses (e.g. evaporation from skin and
lungs, losses into hidden spaces such as the intestine, and
diarrhoea) must be estimated and added to the recorded
losses to calculate the patient's subsequent fluid require-
ments (see Ch. 9).
Table 34.1 The postoperative ward round: a daily
checklist
:
A fresh assessment of each patient is required at
each ward round, often daily but more frequently
for seriously ill patients- Only a few factors may
change on each occasion but all should be
considered.
Look at the patient, look at the charts, took at
the drug chart and communicate.
Enquire
General comfort
Pain control
Thirst
Specific symptoms
Examine
General condition
Respiration and chest (oxygen saturation if
appropriate)
Surgical wound
Peripheral circulation/nerves (vascular/limb
surgery)
Drains and tubes (content, kinks or blockage, loss
of vacuum)
Pressure areas
Drip sites
Check
• Pulse and blood pressure
Temperature
Urine output
Fluid balance (assess insensible loss. e.g.
sweating, diarrhoea)
Special monitoring (e.g. diabetics - blood sugars)
Results of blood testsVinvestigations
Review
NutritionVoral fluid and dietary intake
Analgesia management
Intravenous fluid prescription (volume, sodium
and potassium need)
Antibiotic prescription
Other postoperative drugs
Regular prescription medicines (when to start
oral medication)
inform
• What operation/treatment has been done and
result
• Comment on progress over previous 24 h
• Expected course over next few days
• Results of investigations/histology
• Likely day of discharge (identify any special
requirements early)
Co mm uni cafe
• Receive reports from named nurse,
physiotherapist, etc.
• Advise changes of management
• Advise frequency/nature of observations required
• Write in the notes
351
POSTOPERATIVE
Fluid requirement
For the typical 70 kg patient, intravenous fluid require-
ment after operation is 2.5 litres per day, of which 0.5 litre
is normal saline and the remainder 5% dextrose; potas-
sium is added after the first 24 h once 1 .5 litres of urine
have been passed. Typically the sodium requirement is
1 mmol kg -1 (normal saline contains 140 mmol l" 1 of
sodium) and potassium 1 mmol kg -1 .
If the dissection area at operation has been large, there
will be a greater loss of plasma into the operation site and
this may need to be replaced with colloid (e.g. Haemaccel)
in the early postoperative period. In addition to these
basic requirements, gastrointestinal losses are replaced
volume-for-volume with normal saline with added pot-
assium. Daily plasma urea and electrolyte measurement
are advisable while the patient is dependent on intra-
venous fluids.
Monitoring
Clinical monitoring should include asking the patient
about thirst, assessing central and peripheral perfusion,
examination of dependent areas for oedema, and auscul-
tation of the chest. Tachycardia is an important sign that
can indicate fluid overload or dehydration, but is also
caused by inadequate analgesia.
Patients in whom fluid balance is difficult to manage,
or where there is a particular risk of cardiac failure, may
require central venous pressure monitoring or even left
atrial pressure recording.
Hypovolaemia
Oliguria (defined as a urine output of less than 20 ml h" 1
in each of two consecutive hours) in postoperative
patients is caused by hypovolaemia in the majority of
cases, but always consider a blocked catheter or cardiac
failure. Hypovolaemia may be due to:
• Unreplaced blood loss
• Loss of fluid into the gastrointestinal tract
• Loss of plasma into the wound or abdomen
• Sequestration of extracellular fluid into the 'third'
space.
Blood transfusion
Haemoglobin measurement will be a guide to the need
for blood transfusion unless plasma or extracellular fluid
loss causes an artificially high measurement; this is most
likely in the first 24 h after surgery and it is generally not
necessary to monitor haemoglobin levels more than 72 h
postoperatively. In a stable patient, a top-up transfusion
is indicated if the haemoglobin level is less than 8 g%
(determined by studies in Jehovah's Witnesses), while
above this level patients should be given oral iron. An
unstable patient, one who may rebleed, requires a higher
threshold for transfusion of at least 10 g%. If blood trans-
fusion is given, frequent, regular monitoring of pulse,
blood pressure and temperature are routine to detect a
transfusion reaction.
Complications
A major ABO incompatibility can result in an anaphylac-
tic hypersensitivity reaction (flushing /urticaria, broncho-
spasm, hypotension). Incompatibility of minor factors is
usually less severe and is indicated by tachycardia,
pyrexia and possible rash and pruritus. The transfusion
should be stopped, some blood sent for culture (both from
patient and donor blood) and the remainder of the unit
returned to the blood bank for further cross-matching
against the patient's serum. However, if the reaction is
mild it may be appropriate to give steroids or an anti-
histamine and to continue the transfusion (see Ch. 8).
Nutrition
Nutrition in postoperative patients is frequently poorly
managed and treatment delayed. Dietary intake should
be monitored in all patients, but usually only requires
specific management in patents undergoing major
abdominal surgery or in whom eating or swallowing is
impossible. A basic indication for postoperative nutri-
tional support is inability to eat (actual or expected) for
more than 5 days. Serum protein is a crude but easily
measured index of nutrition, and measurement of weight
is useful over a period of time; more specific tests such as
skin-fold thickness or estimation of nitrogen balance are
used infrequently (see Ch. 10).
If nutritional support is required, enteral feeding is
preferable, if possible, because it has a lower complica-
tion rate than parenteral nutrition. Fluid balance and
electrolyte monitoring are required and treatment
should be given to reduce diarrhoea, which may be pre-
cipitated by high calorie regimens. Parenteral feeding
requires monitoring of the venous access point for
sepsis, plasma and urinary electrolytes, blood sugar,
plasma trace elements (e.g. magnesium) and liver func-
tion. The patient's fluid balance must be carefully
managed.
Surgical drains
Nasogastric tubes
Nasogastric tubes drain fluid and swallowed air from the
stomach and should be left on free drainage at all times
352
POSTOPERATIVE CARE
34
with intermittent aspiration (4-hourly). There is rarely a
need to leave a nasogastric tube spigoted; once drainage
has fallen below 100-200 ml per day the tube can be
removed.
Erosion by the drain of adjacent tissue
Fracture of drain during removal (retained foreign
body).
Chest drains
Pleural drains are attached to an underwater seal
because the pleural space is at subatmospheric pressure.
If the lung does not expand fully, then low pressure,
high volume suction may be added. When a drain is
bubbling it should not be clamped because there is a
danger of tension pneumothorax if the clamp is forgot-
ten or left too long; however, it is essential that the bottle
is never raised above the level of the patent's chest, as
there is a risk that fluid will syphon back into the pleural
cavity.
The drain is removed when:
• Bubbling has stopped for 24 h
• There is no bubbling when the patient coughs
• The daily chest X-ray shows that the lung is fully
expanded.
Check X-rays should be taken at 24 and 48 h after removal
of the drain.
Drains at the operative site
Drains at the operative site are used for the removal of
anticipated fluid collections, not as an alternative to ade-
quate haemostasis, and are usually simple tube drains or
suction drains (check daily that the vacuum is main-
tained). Such drains should be removed early; if left in
place they will not reduce the risk of a subsequent abscess
and may introduce infection, if there is a chronic collec-
tion of fluid (such as an abscess or empyema) the drain
may be left for several days to create a track. This type of
drain is often removed a few centimetres at a time over
several days (shortening) in an attempt to prevent the
track closing too quickly; a sinogram may be used to
confirm that the abscess cavity is shrinking.
DAYCASE SURGERY
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After daycase operations the postoperative period is
inevitably short, but management should follow the same
basic principles outlined above. Special considerations are:
* Is the patient being discharged to a suitable
environment?
* Can adequate, non-parenteral pain control be
achieved?
* Possible side-effects of sedation and anaesthesia.
Patients who have had a general anaesthetic or sedation
must be accompanied home and should not drive for at
least 24 h. Written advice and instructions should be
given both to the patient and to the accompanying
relative or friend.
Local anaesthetic
The main problems with local anaesthesia are systemic
toxicity of the anaesthetic agent and reactionary haemor-
rhage if adrenaline (epinephrine) has been employed.
Toxicity
All the commonly used local anaesthetics (lidocaine
(lignocaine), bupivicaine and prilocaine) are cardiotoxic.
Initial symptoms are paraesthesiae around the lips, tin-
nitus and /or visual disturbance. These are followed by
dizziness, which may progress to convulsions and cardiac
arrhythmia and collapse. Such complications are pre-
vented by strict adherence to maximum dosage schedules
(Table 34.2).
Treatment of systemic toxicity is directed firstly
towards maintaining ventilation (hypotension is uncom-
mon in the absence of hypoxia):
Complications
All drains have similar potential complications:
• Trauma during insertion
• Failure to drain adequately due to
- incorrect placement
- too small size
- blocked lumen
• Complications due to disconnection
• Introduction of infection from outside via the drain
track
Tabic 34.2 Maximum doses of anaesthetic agents
Lidocaine
(lignocaine)
Buptvacaine
Prilocaine
Plain solution With adrenaline
(mg) (epinephrine) (mg)
200
(20 ml of 1%)
150
(30 ml of 0.5%)
400
(80 ml of 0.5%}
500
(50 ml of 1%)
200
(40 ml of 0.5%)
600
(120 ml of 03%)
353
POSTOPERATIVE
• Give 100% oxygen and maintain the airway (by intu-
bation if necessary)
• Control convulsions with intravenous diazepam
• Establish an ECG monitor; various arrhthymias can
occur
• If cardiac arrest occurs, start with high energy
(360-400 J) DC shock and continue resuscitation
attempts for at least 1 h.
Sedation
For sedoanalgesia or sedation alone (e.g. endoscopy
patients), particular attention is paid to monitoring respir-
ation. During upper gastrointestinal endoscopy, delivery
of oxygen by nasal spectacles is mandatory. All sedated
patients should have a pulse oximeter attached during the
procedure and until they are fully awake. The use of the
antagonist flumazenil to reverse the sedative effects of
benzodiazepines can be associated with delayed respir-
atory depression as the reversal agent may have a shorter
half-life than the sedative itself. Midazolam/ with a
shorter half-life, is preferred to diazepam. All patients
given sedation should be observed for at least 2 h before
being sent home.
CARE AFTER HOSPITAL DISCHARGE
The key is good communication. The patient should
understand what treatment he or she has had, its effect,
the likely time period required to complete recovery and
special restrictions on normal activity. Whenever appro-
priate, the relatives should also have this information. As
many complications (e.g. wound infection) occur in the
first week or two after hospital discharge, it is essential
that the patient's general practitioner is aware of the diag-
nosis and treatment given and also what information the
patient has received. Ensure arrangements are made to
communicate histology results to the patient and plans
for additional investigation or treatment have been made
and explained to the patient.
Postoperative care
Adequate management of postoperative pain
is essential.
Poor management of fluid balance is probably
the greatest cause of avoidable morbidity after
major surgery.
It is essential to know the maximum dosage for
local anaesthetic agents and how to manage
toxicity.
Clear and concise communication with the
patient and other health professionals
involved in care will prevent problems and
confusion.
PROBLEMS IN THE POSTOPERATIVE
PATIENT
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The incidence and nature of postoperative complications
depends upon the nature and extent of the operative
intervention (see Ch. 36). Many are self-evident, but some
specific problems are discussed below.
Cyanosis/respiratory inadequacy
The time between onset of respiratory problems and
surgery may suggest the cause. In the recovery phase, it
may be due to inadequate reversal of anaesthesia or
excess opiates and the anaesthetist should be called.
Opiate overdosage usually presents in a drowsy patient
with shallow, infrequent breaths, while airway obstruc-
tion is associated with obvious efforts to breathe,
undrawn intercostal muscles and agitation.
Airway obstruction
If a patient is in respiratory distress, give verbal reassur-
ance and 100% oxygen by mask. If cyanosed, check the
pulse, as the most common cause is cardiac arrest. If
breathing appears obstructed, call for anaesthetic help
and:
• Inspect the mouth for foreign bodies (e.g. vomit,
slipped denture and surgical swab after surgery in the
mouth).
• Extend the neck and pull the jaw forward to clear the
tongue from the back of the mouth and get an assistant
to maintain the position.
• Insert an oral airway.
• If the patient has had a thyroidectomy, open the
wound (skin and deep fascia) at the bedside.
• If the patient has had surgery in the mouth, throat or
neck, or if there is no improvement with an airway in
place perform a cricothyroidotomy without delay.
• Check that the patient can exhale.
• Monitor the oxygen saturation and obtain blood gases
and chest X-ray as soon as possible.
354
POSTOPERATIVE CARE
34
Do not attempt to intubate a patient after surgery in the
mouth or neck unless experienced: do a cricothyroido-
tomy and call an anaesthetist. In an emergency, a
large-gauge intravenous cannula can be used for
cricothyroidotomy but requires jet ventilation, whether
the patient is breathing or not, because of the small
lumen (attach a rigid oxygen line to the cannula via the
barrel of a 5 ml syringe). During insertion, check that the
needle is in the trachea, which may be displaced, by
aspiration of air and be careful not to pass it straight
through the back. The cannula can kink or displace and
should be replaced as soon as possible with a purpose-
made device.
• Increase the rate of intravenous fluids.
• Elevate the legs.
• Give oxygen up to 50% by mask.
• Obtain an ECG (dysrhythmia, acute ischaemia, signs of
pulmonary embolus).
If the ECG is normal, place a central venous pressure line
while giving additional intravenous fluid. Listen to the
chest to exclude tension pneumothorax (chest trauma,
chest surgery, surgery around the oesophageal hiatus, or
failed neck line) and consider pulmonary embolus and
septicaemia. If no cause is apparent, and the blood pres-
sure responds to volume infusion, hidden blood loss is
likely.
Normal breathing
Cyanosis in a patient who appears to be breathing nor-
mally may be due to a problem in the lungs or circulation.
Listen to the chest for bronchospasm (wheeze is absent in
severe bronchospasm) and for uniform air entry. Is the
patient asthmatic? Is this a hypersensitivity reaction? Loss
of air entry in the upper chest suggests pneumothorax,
and in the dependent part of the chest, haemothorax or
pleural effusion. Has the patient had attempts at intra-
venous line insertion in the neck?
Acute circulatory problems that can cause cyanosis
are loss of venous return (massive sudden blood loss),
pump failure (myocardial infarct) and obstruction
(massive pulmonary embolus). Check the blood pres-
sure and get an ECG. Other possible causes include
severe adverse drug reaction and severe sepsis (air
hunger).
Hypotension
The commonest cause of hypotension in a postoperative
patient is hypovolaemia, either due to inadequate fluid
replacement or to bleeding. Myocardial infarction needs
to be considered and excluded. Poor management of
pain control, either too much or too little analgesia, may
be a factor and hypotension is a side-effect of an epi-
dural (local anaesthetic drugs may cause dilatation of the
main capacitance vessels). It is difficult to confirm that
an epidural is responsible without turning it off;
however, treatment by volume replacement is the same
whether hypotension is caused by hypovolemia or the
epidural.
An assessment of the overall clinical situation may
suggest an obvious cause of hypotension in a given
patient If not:
Hypertension
This may be dangerous in patients with ischaemic heart
disease, cerebrovascular disease or following vascular
surgery. Obtain anaesthetic assistance with the manage-
ment of such patients if a cause cannot be found; the
commonest causes of hypertension are inadequate
control of pain and /or anxiety, urinary retention and
shivering.
Postoperative infection
The patient's temperature is a basic, but crude, observa-
tion for infection. Clinical monitoring includes exami-
nation of the chest and inspection of the wound. The
upper limit of normal temperature is 37°C, but there
is considerable variation and occasionally a patient may
be pyrexial despite a temperature below this 'magic'
figure. The timing of postoperative pyrexia may suggest
a cause (e.g. after a large bowel resection: pyrexia within
the first 48 h - chest infection; fifth or sixth day - an
anastomotic leakage or wound infection; tenth day -
venous thrombosis).
If a patient develops a pyrexia, a routine 'infection
screen' is carried out:
1 . Examine the chest - chest X-ray; sputum for culture;
ECG (if ?pulmonary embolus).
2. Examine the wound - wound swab for culture.
3. Enquire about urinary symptoms - urine culture.
4. Examine for signs of deep vein thrombosis.
5. Examine intravenous sites (phlebitis) and other
catheter sites (epidural).
6. Examine pressure areas.
7. If a child - look in the ears and mouth.
8. If cause uncertain - send blood cultures; measure
white cell count.
355
POSTOPERATIVE
9. Consider the underlying disease (e.g. pyrexia of
malignancy).
10. Consider hidden infection (e.g. subphrenic or pelvic
abscess).
Delayed gastric emptying/aspiration
Abdominal surgery is frequently associated with
delayed gastric emptying and impaired colonic motility,
even though small bowel activity, and hence bowel
sounds, may return relatively early. If there is intra-
abdominal sepsis, metabolic disturbances or retroperi-
toneal haematoma or inflammation there may be
prolonged inactivity of the small bowel also (paralytic
ileus). Colonic pseudo-obstruction occurs most often in
elderly patients confined to bed (e.g. after fracture or
orthopaedic surgery) and postpartum. Reintroduction of
diet too soon can lead to gastric dilatation with vomiting
and the risk of aspiration. Monitoring nasogastric aspir-
ates, abdominal distension and the passage of flatus
determines the timing of reintroduction of normal diet.
However, a restricted intake of oral fluids (30 ml h -1 ) is
permissible almost without exception, and increases
patient comfort.
Gastric aspiration can be life-threatening:
• Place the patient head-down in the recovery position.
• Suction out the mouth.
• Give 100% oxygen by mask.
• Pass a nasogastric tube to empty the stomach.
• Examine for bronchospasm - if present, §ive nebulized
salbutamol ± intravenous aminophylline and consider
intubation and ventilation.
• Obtain chest X-ray.
• Arrange early chest physiotherapy.
Steroids are not thought to be helpful.
Summary
• Postoperative care is divided into three
phases.
• The recovery phase is the immediate care
of patients after surgery until they can
maintain all vital functions independently.
• The second phase is care on the ward,
during which the three most important
general considerations are pain control,
fluid balance management and nutrition.
• The third phase of care follows discharge
from hospital and includes consideration of
appropriate follow-up and/or survei Hence.
• The intensity of monitoring in the
postoperative phase depends on the
severity of disease and/or the nature of
surgery.
• Many specialized features of postoperative
care are determined by the type of
operation.
• Good communication is essential
throughout postoperative care to ensure
the best outcome.
Further reading
In addition to the chapters in this book referred to in the text, several
pocket-sized texts aimed at trainee anaesthetists are available and
provide useful guidelines on the management of acute postoperative
problems, for example:
Eaton JM, Fielden JM, Wilson ME Anaesthesia action plans.
Abbott Laboratories Ltd, Abbott House, Norden Road,
Maidenhead, Berks SL6 4XE
356
Management of postoperative
pain
V. Sodhi, R. Fernando
m
Objectives
• Define the pathophysiology of pain.
• Define the effects of pain on the
postoperative patient.
• Discuss pharmacological and non-
pharmacological methods of analgesia.
• Discuss the assessment of postoperative
pain.
• Discuss the causes and treatment of
postoperative nausea and vomiting.
INTRODUCTION
^##^$,^^
Key points
• Up to 75% of postoperative patients
experience moderate to severe pain.
• In many cases this pain is not relieved
adequately.
A joint working party was set up by the Royal College of
Surgeons and College of Anaesthetists in 1990 to address
these findings. They concluded that the main failures
were:
• That postoperative pain is given low priority in ward
regimens
• Lack of education among medical and nursing staff
• Lack of provision of responsible personnel to manage
postoperative pain.
Despite some advances in our understanding of the physi-
ology of acute pain and the introduction of some new
analgesics, improvements in the quality of acute pain
management in the past 10 years have tended to focus on
using existing drugs and techniques more effectively.
Better postoperative pain control has been demonstrated
following the sequential introduction of a staff education
programme, pain scoring and a more proactive regimen
for administering intramuscular morphine. Further,
although less dramatic, improvements were seen when
the more expensive 'high tech' interventions, such as
patient-controlled analgesia (PC A) and epidural infusion
analgesia were added.
WHAT IS PAIN?
^i^M^^^^m^^
The International Association for the Study of Pain (IASP)
defined pain as 'an unpleasant sensory and emotional
experience associated with actual or potential tissue
damage'. This definition is important, as it states that pain
is never only a physical sensation but always ultimately
a psychological event, and responses to a given stimulus
are variable between individuals. Pain perception thresh-
old is defined as the least experience of pain that a subject
can recognize. It is highly reproducible in different indi-
viduals and in the same individual at different times. Pain
tolerance threshold, defined as the greatest level of pain
that the subject is prepared to tolerate, is, in contrast,
highly variable. That is, it can vary from person to person
and within the same individual on different occasions. It
is highly dependent on psychological variables, including
cultural factors, past experience and the meaning of the
pain for the individual
HOW DOES POSTOPERATIVE PAIN
ARISE?
s««^iS^W!mS«^!;^SSftW^,^M^^
Pain involves four physiological processes: transduction,
transmission, modulation and perception. Pain begins
when local tissue damage, a noxious stimulus, occurs
during surgery, causing the release of inflammatory sub-
stances (prostaglandins, histamine, serotonin, bradykinin
and substance P). This leads to the generation of electri-
cal impulses (transduction) at peripheral sensory nerve
endings, or nociceptors. These electrical impulses are con-
ducted by nerve fibres (A-delta and C fibres) to the spinal
357
35
POSTOPERATIVE
cord (transmission). Further relay to the higher brain
centres can be modified within the spinal cord (modula-
tion) before an individual perceives a painful stimulus
(perception). Therefore pain can, in theory, be blocked at
various levels in this complex chain. Non-steroidal anti-
inflammatory drugs (NSAIDs) can reduce the peripheral
inflammatory response by reducing prostaglandin pro-
duction. Local anaesthetic drugs injected into the epi-
dural or subarachnoid spaces can block impulses to the
spinal cord by acting on spinal nerve roots. Opioids can
produce analgesia through modulation by binding to
opioid receptors in the spinal cord and other higher brain
centres such as the periaqueductal grey, the nucleus raphe
magnus and the thalamus, whereas binding to opioid
receptors in the cerebral cortex can affect the perception
of pain (Fig. 35.1).
Skin
Post central gyrus
Internal capsule
Thalamus
Dorsal root ganglion
Spinothalamic + Spinoreticular tracts
?
Dorsal horn of
* \
% — *
• i
* *
** ** Ascending
tracts
Spinal cord
Site of action
1. Nocioceptors in skin and subcutaneous tissues
These receptors are stimulated by inflammatory
substances, e.g. prostaglandins
2. A- beta fibres
Stimulation of these fibres inhibits transmission
of pain to higher centres
3. Primary afferent neurons (A-delta, C fibres)
Transmit impulses from nocioceptors to the
spinal cord
4. Dorsal horn of spinal cord and higher centres
Further relay/transmission of painful stimuli to
the cerebral cortex
Analgesic /effect
NSAIDS, e.g. diclofenac, ibuprofen, ketorolac,
block pathways involved in the formation of
inflammatory agents
Transcutaneous electrical nerve stimulation (TENS);
stimulates A-beta fibres
Local anaesthetics, e.g. lidocaine, bupivacaine,
ropivacaine. Block the transmission of impulses
along neurons
Opioids, e.g. morphine, pethidine, diamorphine,
fentanyl, act as agonists at opioid receptors [also
ketamine]
Fig. 35.1 Sites of action of common analgesics.
358
MANAGEMENT OF POSTOPERATIVE PAIN
35
WHY SHOULD WE TREAT
POSTOPERATIVE PAIN?
^fflZ&%i?ffi£S;ffi$^H&i~?fffi^$&&ff/!& 1 fi^&'i'f,
#W%Jf^&;ffi;f$iJ?£>f/>
Apart from the humanitarian aspect, it is accepted that
effective postoperative pain relief is fundamental to good
quality patient care and is a legitimate therapeutic goal.
There is increasing evidence relating good postoperative
analgesia to reduced clinical morbidity. Some authorities
suggest that there may be economic benefits associated
with enhanced patient well-being and early rehabilita-
tion. There are also several physiological reasons for treat-
ing postoperative pain.
Respiratory effects
Surgery involving the upper abdomen or chest reduces
vital capacity, functional residual capacity and the ability
to cough and deep breathe. This in turn can lead to reten-
tion of secretions, atelectasis and pneumonia. Inadequately
treated pain aggravates these changes, while analgesia
improves respiratory function.
Cardiovascular effects
Pain causes an increase in sympathetic output (tachycar-
dia, hypertension and increasing blood catecholamines),
which leads to increasing myocardial oxygen demand,
which may in turn increase the risk of postoperative
myocardial ischaemia, especially in those patients with
pre-existing cardiac disease.
Neuroendocrine effects
The stress response to surgery and pain includes the
secretion of catecholamines and catabolic hormones. This
increases metabolism and oxygen consumption and pro-
motes sodium and water retention.
Effects on mobilization
Mobilization of a patient in the postoperative period may
be delayed if the patient is experiencing pain. This may
in turn increase the risk of developing a deep vein
thrombosis and also prolong hospital stay.
patient preoperatively as to the nature of the operation,
likely postoperative pain and methods of analgesia avail-
able. Ideally, assess each patient jointly with the anaes-
thetist and a member of the nursing staff, to discuss the
site and nature of the surgery (Table 35.1), the extent of
the incision and the physiological and psychological
make-up of the patient, which are all relevant in planning
intraoperative and postoperative analgesia. Once these
things have been ascertained, the various methods avail-
able for postoperative analgesia (including opioids,
NSAIDs, isolated nerve blocks and epidural and spinal
anaesthesia and analgesia) can be discussed between the
patient and medical staff in order to reach a mutually
agreeable postoperative treatment plan.
Transcutanenous electrical nerve stimulation
(TENS)
A TENS machine consists of a pulse generator, an ampli-
fier and a system of electrodes. It acts by stimulating
afferent myelinated (A-beta) nerve fibres at a rate of
70 Hz. This activates inhibitory circuits within the spinal
cord that reduce the transmission of painful nerve
impulses to the higher cortical centres, thereby theoreti-
cally reducing the level of postoperative pain. However,
in a systematic review of studies of TENS in postopera-
tive pain relief, 15 out of 17 randomized control trials
found no benefit compared with placebo. TENS has been
shown to exert maximal relief in neurogenic pain, which
is experienced in phantom limb pain and following nerve
damage.
Acupuncture
Acupuncture has been clinically evaluated in postoper-
ative patients. Although there is some variability in the
way in which acupuncture is administered, there are a
number of studies that suggest that it reduces pain and
analgesic consumption after dental and abdominal surgery.
Other methods
Massage, hypnosis or application of superficial heat or
cold are sometimes used.
METHODS AVAILABLE TO TREAT
POSTOPERATIVE PAIN
NON-PHARMACOLOGICAL
?^W&W&F&'&#W£&,
yS^i'!;^:-^
Preoperative counselling
The management of postoperative pain does not begin
after the completion of surgery. Therefore inform your
_ _
Table 35,1 Pain associated with different surgical
procedures (decreasing order of severity)
Thoracic surgery
Upper abdominal surgery
Lower abdominal surgery
Inguinal and femoral hernia repair
Head/neck/limb surgery
359
35
POSTOPERATIVE
Key point
Although there is little evidence to support the
effectiveness of unconventional methods,
certain patients do derive some benefit from
them, so do not dismiss them without
consideration.
PHARMACOLOGICAL
i&^S-^Ss^^^
■'?:^^S&S^'^
In the majority of cases, acute pain is managed solely with
drugs. There is good evidence that patients benefit from
the use of multimodal, or balanced, analgesia after
surgery. This involves the use of a variety of different
classes of analgesics in combination, perhaps given by
different routes, to achieve pain relief with a reduction in
the incidence and severity of side-effects.
Paracetamol
Paracetamol is effective for mild to moderate pain, and as
an adjunct to opioids in more severe pain. It has both
analgesic and antipyretic effects but is not thought to be
anti-inflammatory. Although there remains some contro-
versy regarding its mechanism of action, it is generally
thought to act by inhibiting the cyclo-oxygenase enzyme
in the central nervous system, while sparing peripheral
prostaglandin production. It is rapidly absorbed from the
gut, and peak plasma levels are reached 30-60 min after
oral administration. Paracetamol is metabolized in the
liver and excreted by the kidneys, thus its dose should be
decreased in renal and hepatic impairment. Contra-
indications include acute liver disease, alcohol-induced
liver disease and glucose-6-phosphate dehydrogenase
deficiency. Oral paracetamol is more effective when com-
bined with other compounds such as codeine, dihydro-
codeine or dextropropoxyphene. Numerous different
compound preparations are available.
Key point
• Be careful to avoid inadvertent overdose of
paracetamol when prescribing by mixing
different compound preparations.
If the oral route is inappropriate, paracetamol may be
given rectally. In some European countries the drug is
given intravenously, as the precursor propacetamol, 2 g of
which is converted to 1 g of paracetamol. Studies have
shown propacetamol to be a more effective postoperative
analgesic than paracetamol. A recent study demonstrated
a 46% decrease in opioid requirement in orthopaedic
patients given regular propacetamol.
NSAIDs
Sodium salicylate, a chemical manipulation of the glyco-
side salicin obtained from extracts of willow bark, was
introduced in 1875 to treat rheumatic fever. Acetylsalicylic
acid (aspirin) was introduced about 25 years later and
since then numerous NSAIDs have been marketed,
including diclofenac, ibuprofen and ketorolac.
NSAIDs do not relieve severe pain when used alone,
but they are valuable in multimodal analgesia because
they decrease opioid requirement and improve the
quality of opioid analgesia. They have the benefit of
improved analgesia without sedation or respiratory
depression, and are more effective for the pain associ-
ated with movement than opioids. There is no evidence
that NSAIDs given rectally or by injection perform any
better or more rapidly than the same dose given orally.
These routes become appropriate when the patient
cannot swallow or absorb drugs from the gastrointesti-
nal tract.
Km
Key point
The adverse effects of NSAIDs are potentially
serious, and it is imperative that you respect
any contraindications to their use.
The most important adverse effects for surgical patients
are:
• Gastric ulceration - avoid NSAIDs in patients with
symptoms of gastrointestinal intolerance and ulceration.
• Nephrotoxicity - risk factors include concomitant use
of nephrotoxic antibiotics (e.g. gentamicin), increased
intra-abdominal pressure (e.g. at laparoscopy), hypo-
volemia and age greater than 65 years.
• Impaired haemostasis - NSAIDs inhibit the production
of prostaglandin thromboxane A 2 within platelets,
resulting in reduced platelet aggregation. They may
also increase the risk of bleeding.
• Aspirin-induced asthma - NSAIDs may induce bron-
chospasm in susceptible patients.
NSAIDs block the synthesis of prostaglandins by inhibit-
ing the enzyme cyclo-oxygenase, of which there are at
least two isoenzymes, COX 1 and COX 2. Research has
shown that COX 1 synthesizes prostaglandins responsi-
ble for physiological housekeeping functions, which
360
MANAGEMENT OF POSTOPERATIVE PAIN
35
include gastrointestinal and renal protection. COX 2, on
the other hand, is responsible for the biosynthesis of
inflammatory prostaglandins. Thus it would seem logical
that by selectively inhibiting COX 2 it would be possible
to develop an NSAID which retained the anti-inflamma-
tory, analgesic and antipyretic actions required, without
the undesirable side-effects of gastric irritation and renal
injury. Two highly selective COX 2 inhibitors (celecoxib,
rofecoxib) are now available, and have been shown to
cause significantly less gastric mucosal injury than non-
selective NSAIDs in patients without gastrointestinal
pathology. However, some caution has been expressed
over these findings. Chronic treatment with selective
COX 2 inhibitors in patients with pre-existing gastro-
intestinal injury or inflammation may show a significant
increase in damage. COX 2 appears to have an important
role in promoting the healing of ulcers. The overall effec-
tiveness of this group of drugs therefore awaits the
outcome of long-term trials.
• Orally absorbed opioids from the gut reach the liver,
via the splanchnic blood flow, where they are highly
metabolized (first-pass metabolism), causing insuffi-
cient plasma concentrations of drug, e.g. 70% of orally
administered morphine is eliminated through first-pass
metabolism. Pethidine, morphine and codeine are all
available as oral preparations.
The intramuscular route is the traditional method of
administration. It is convenient and is associated with few
side-effects, although the degree of analgesia varies
between patients. Up to 40% of patients on a p.r.n. intra-
muscular opioid regimen may have inadequate pain
relief. The dose prescribed should be based on the
patient's age and medical condition. The onset of analge-
sia following intramuscular morphine begins after about
20 min, with a peak effect at about 60 min. With careful
patient selection, and nursing staff trained to use this
administration technique correctly, intramuscular opioids
can thus be highly effective.
Opioids
The analgesic properties of opium were first described
over 6000 years ago, and opioids are still the first-line
treatment for severe postoperative pain in most patients.
They act at opioid receptors in the spinal cord and
higher brain centres to produce analgesia. The three
main subtypes of receptor have most recently been classi-
fied as OP1 , OP2 and OP3 (formerly 8, k and (x, respec-
tively). Opioids mimic endogenous opioid peptides at
these receptors, causing their activation within the
central nervous system. This decreases the activity of the
dorsal horn relay neurons that transmit painful stimuli,
thereby reducing the transmission of these stimuli to
higher centres and producing analgesia. Activation of
the receptors also causes the unwanted side-effects of
opioids, namely, itching, sedation, respiratory depres-
sion, nausea and vomiting, euphoria or dysphoria and
bladder dysfunction.
Opioids may be administered orally, intramuscularly,
intravenously or centrally (into the epidural or subarach-
noid space by an anaesthetist). Although novel tech-
niques such as transdermal, inhalational and rectal
administration of opioids have been used, and may offer
certain advantages over conventional routes, their place
in mainstream postoperative care is unproven.
The oral route for opioids is not recommended initially
after major surgery for the following reasons:
• The use of opioids during general anaesthesia can lead
to postoperative nausea and vomiting and delayed
gastric emptying.
• Intra-abdominal surgery can result in postoperative
ileus.
Key point
• Take care when administering multiple doses of
intramuscular opioids to shocked patients with
poor peripheral perfusion. A large depot of
opioid can accumulate intramuscularly, to be
later released into the bloodstream when the
peripheral circulation is restored, with
unpredictable and often dangerous results.
Morphine, diamorphine and pethidine are also
commonly administered via the intravenous route.
Intermittent intravenous bolus doses allow titration to
effect, although care must be taken not to 'overshoot'. The
peak effect of intravenously injected morphine is reached
at about 15 min, and most of the effect by 5 min. Thus
incremental titration with a 1-2 mg bolus every 5 min
generally represents the best compromise between rapid
pain relief and safety. Continuous infusion of opioid can
abolish the wide swings in plasma drug concentration
found with the intramuscular route and allow adjustment
of the rate to the individual needs of a patient.
Unfortunately, plasma drug concentrations may continue
to increase with such regimens, leading to sedation and
respiratory depression.
Key points
Side-effects of opioids are reversed by the drug
naloxone, which should always be available on
the ward.
361
35 *
POSTOPERATIVE
• Optimum safe analgesia requires reliable
infusion devices, frequent assessment and
monitoring, with appropriate adjustment of
the infusion rate. In UK practice, this level of
care may not always be achievable in a general
ward setting.
Intravenous opioid patient-controlled analgesia (PC A) was
developed to address the need for an improved mode of
administering standard opioids. The first demonstration
of a PC A machine was in 1976 at the Welsh National
School of Medicine, and this became the first commercially
available PC A machine, The Cardiff Palliator'. Modern
PCA regimens have been shown to provide greater patient
satisfaction and improved ventilation compared with
other conventional routes of opioid administration.
PCA is superior to both intramuscular and continuous
infusion routes because it allows the patient to self-
administer small doses of opioid when pain occurs.
PCA is administered using a special microprocessor-
controlled pump which is triggered by depressing a
button held in the patient's hand. When triggered, a
preset amount (the bolus dose) is delivered to the patient,
usually via a separate intravenous line. A timer prevents
the administration of another bolus for a specified period
(the lock-out interval). Before PCA is started, a loading
dose of opioid must be given to achieve adequate anal-
gesia. Background infusions of opioid are no longer used
with PCA because of increasing side-effects. From a safety
aspect, if patients become oversedated on PCA, they
cannot give themselves another bolus. This will lead to a
fall in plasma opioid concentration to safer levels.
Regardless of this, regular monitoring of patients with
PCA is essential. Naloxone should once again be available
to treat respiratory depression and excessive sedation.
Patient selection is again an important factor in the
effectiveness of PCA. The patient must have adequate
preoperative instruction in its use, and be mentally able
to understand the concept of self -administration of pain
relief, as well as be physically able to press the button to
activate the device.
PCA is suitable for many patients:
• After major surgery and who are fasting
• With marked 'incident pain' (e.g. pain associated with
physiotherapy or dressing changes)
• During acute episodic pain (e.g. vaso-occlusive sickle
cell crisis)
• When intramuscular injections are contraindicated (e.g.
coagulopathy).
Relative contraindications for use of PCA are:
• History of illicit drug abuse
• Major metabolic disorders (e.g. sepsis) or severe fluid
and electrolyte abnormalities
• End-stage renal or hepatic disease
• Severe chronic obstructive airways disease
• Sleep apnoea.
Miscellaneous routes of opioid
administration
Transdermal. Fentanyl, a potent short-acting opioid,
has been used in a drug-containing patch which adheres
to the skin. The drug diffuses through the skin and into
the bloodstream. Unfortunately the dose cannot be
titrated to the patient's needs and it may take several
hours to achieve adequate pain relief.
Sublingual. Since the drug is delivered directly into
the bloodstream via the sublingual route, first-pass
metabolism is avoided. Sublingual buprenorphine, a
partial agonist, is available, but has a 20% incidence of
nausea and vomiting and a 50% incidence of sedation or
drowsiness.
Rectal. The rectal route is useful for providing a high
systemic bioavailability of drugs that have a low oral
bioavailability. Absorption, however, is slow, with peak
concentrations being reached 3-4 h after administration.
Pethidine and pentazocine are commonly administered
by this route in Europe.
Subcutaneous. Morphine is commonly administered
by the subcutaneous route in cancer patients and is occa-
sionally used for postoperative pain. This route is better
tolerated than the intramuscular route of administration
but the entry site must be changed every 24-48 h to avoid
infection, and rapid titration of the dose of drug against
patient response is difficult to achieve.
Nebulizer. Morphine, diarnorphine and fentanyl have
all been administered as nebulized solutions, with the
advantage that the lungs can provide a large surface area
on to which the opioids can be rapidly absorbed;
however, systemic absorption is variable, probably
because an indeterminate amount of the agent is swal-
lowed by the patient.
Intra-articular. In orthopaedic surgery, morphine may
be of benefit by binding to opioid receptors that are
present in inflamed tissue formed after injury within the
joint spaces. Systematic review of the literature has so far
failed to reveal evidence of efficacy for this route of
administration.
Epidural and spinal (intrathecal). These routes are dis-
cussed below.
Tramadol - a new opioid
Tramadol is a synthetic analgesic, which has been used
in Germany for over 20 years, but has only been available
in the UK since 1994. It acts as a weak agonist at some
opioid receptors, but also has important non-opioid and
362
MANAGEMENT OF POSTOPERATIVE PAIN
35
central nervous system effects via noradrenergic and
serotoninergic pathways. It can therefore be classified as
both an opioid and a non-opioid analgesic. When given
parenterally, tramadol produces equivalent analgesia to
morphine, except in severe postoperative pain, when it
has been shown to be equipotent to pethidine. The
advantage of tramadol is that it is analgesic with minimal
respiratory depression, sedation, gastrointestinal stasis
or abuse potential. Its disadvantages are its relative
expense and side-effects, including dizziness, nausea,
dry mouth and sweating. It may also lower seizure
threshold.
Relative efficacy of commonly used oral
drugs and intramuscular morphine
Relative analgesic efficacy can be expressed in terms of
the number needed to treat (NNT); that is, the number
of patients who need to receive the active drug for one
to achieve at least 50% relief of pain compared with
placebo over a treatment period of 6 h. For analgesics to
be considered effective they require an NNT of 2-3 or
less. Table 35.2 shows the relative efficacy of some
common analgesics. The results have been gleaned from
many meta-analyses of hundreds of clinical trials involv-
ing thousands of patients. The results should, however,
be interpreted with some caution as they may hide
effects such as non-standardization in the pain being
treated.
Local anaesthetics and regional anaesthesia
The use of local anaesthetics for the treatment of acute
pain can be traced back to the time of the Pharaohs.
Hieroglyphics show that the ancient Egyptians used a
Ta bl e 3 5.2 Rel at i ve efficacy
of common analgesics
Analgesic
Number needed
to treat
Paracetamol 1 g
4.6
Paracetamol 1 g + codeine 6C
1 mg
3
Codeine 60 mg
18
Dihydrocodeine 30 mg
10
Tramadol 50 mg
8.9
Tramadol 100 mg
4,8
Tramadol 150 mg
2.9
Diclofenac 50 mg
23
Diclofenac 100 mg
2.1
Ibuprofen 200 mg
5.5
Ibuprofen 400 mg
2.9
Morphine 10 mg (single Lm. <
dose)
2.9
topical substance to ease the pain of circumcision. Local
anaesthetic (LA) drugs (e.g. bupivacaine, ropivacaine and
lidocaine (lignocaine)) are sodium channel blockers and
as such prevent the propagation of nerve impulses when
applied to peripheral nerves or nerve roots. Sensory and
sympathetic nerve fibres are blocked by smaller amounts
of LA than are motor nerves. In the treatment of post-
operative pain, LA drugs can be used in many ways:
• Local wound infiltration (e.g. after an inguinal hernia
repair)
• Injection close to a peripheral nerve (e.g. digital nerves
in a ring block)
• Injection close to a plexus of nerves (e.g. brachial plexus
in an axillary block)
• May be used to provide central neural blockade (e.g. a
spinal or epidural).
Key point
• All local anaesthetic drugs can cause toxic
effects if given in large doses or if accidental
intravascular injection occurs. Central nervous
system and cardiovascular toxicity can result in
restlessness, hypotension, convulsions, cardiac
arrhythmias and even cardiorespiratory arrest.
Suggested safe maximum doses of LA are 2 mg kg -1 for
plain bupivacaine and 3 mg kg" 1 for plain lidocaine. LA
solutions are also available with small amounts of
adrenaline (epinephrine) (e.g. 1 in 200 000), which, acting
as a vasoconstrictor due to its action on alpha- 1 receptors,
reduces the absorption of the LA, thereby allowing larger
volumes of LA to be given. Adrenaline (epinephrine) has
also been found to act on alpha-2 receptors in the spinal
cord, which helps to potentiate the analgesic effect of local
anaesthetics at spinal cord level.
Key point
• Remember that injection of adrenaline
(epinephrine)-containing solutions is absolutely
contraindicated in areas supplied by end
arteries, such as the fingers, toes and the
penis, as prolonged ischaemia may lead to
tissue necrosis.
Bupivacaine is the most commonly used LA drug for
both central and peripheral nerve blockade by virtue of its
relatively long duration of action (2-3 h). It is prepared
commercially as a racemic mixture of its R and S isomers.
363
35
■ . -■,-.. ■■■„ „^. -...■,;-- .-^-r.^^-r^-^
POSTOPERATIVE
The R isomer is thought to be responsible for the main
drawbacks of bupivacaine, that is its greater potential for
cardiac and central nervous system toxicity and the fact
it can also cause profound motor block in high concen-
tration. The drive within the pharmaceutical industry to
produce single isomer drugs with improved safety has
resulted in the manufacture of two new LA drugs, ropi-
vacaine and levobupivacaine.
Ropivacaine is the S isomer of the propyl homologue of
bupivacaine, and was claimed by its manufacturers to be
less cardiotoxic than its parent drug, and also to have a
more selective blockade on A-delta and C fibres, produc-
ing less motor blockade. However, further research has
shown that it is about 40% less potent than racemic bupi-
vacaine, so that in equipotent doses there may be no sig-
nificant difference between them.
Levobupivacaine is the S isomer of bupivacaine itself,
and has a more favourable safety profile in laboratory
testing than the racemate. Clinical trials have shown it to
have similar potency to racemic bupivacaine.
Epidural analgesia
The epidural space is a fat-filled space within the spinal
canal. Anaesthetists inject local anaesthetics into this
space, and, by doing so, block nerve root transmission of
pain. Epidural opioids can also modulate pain pathways
once within the epidural space by diffusion through the
dura rnater into the cerebrospinal fluid (CSF) and so to the
opioid receptors of the spinal cord. A continuous epidural
infusion using an indwelling epidural catheter, through
which drugs are given for postoperative analgesia, is the
most common catheter technique used for acute pain.
Most hospitals in the UK nowadays use epidural infu-
sions consisting of combinations of low dose LA (e.g.
bupivacaine 0.1%) and opioid (e.g. fentanyl 0.0002% or
2 (xg ml" 1 ). Such low dose combinations are synergistic.
Side-effects related to epidural opioids alone include
nausea and vomiting, pruritus, sedation and delayed res-
piratory depression. Low dose mixtures, by reducing the
amount of both LA and opioid, actually reduce the side-
effects of both drugs. However, monitoring of the patient
is still important. Naloxone should once again be avail-
able to reverse opioid side-effects such as excessive
sedation and respiratory depression. Typically, patients
receiving low dose LA plus opioid epidural infusions
have superior analgesia, improved cardiovascular stabil-
ity, and the ability to mobilize due to a reduction in motor
block. A relatively novel method of epidural pain relief,
which may become more common, is patient-controlled
epidural analgesia (PCEA). Similar to the PC A, it allows
the patient to titrate the analgesia required. The same low
dose mixture of bupivacaine and fentanyl can be used for
a PCEA regimen.
Indications for epidural analgesia include:
• Surgery (intraoperative and postoperative)
• Trauma (especially fractured ribs or pelvis)
• Labour pain
• Acute ischaemic pain
• Severe angina not controlled by conventional means
(seldom used but some papers have shown a clear
benefit).
Absolute contraindications are patient refusal, allergy to
LA drugs, infection at the site of insertion, and lack of
resuscitation equipment or skills. Relative contraindica-
tions require an assessment of the individual's risk
and benefit, and include hypovolemia, coexisting
neurological disease, coagulopathy and compartment
syndrome.
The benefits of epidural analgesia include:
• Effective analgesia (especially thoracic and major
abdominal surgery)
• Reduced opioid requirement
• Reduction in the stress response after surgery
• Reduction in the incidence of deep vein thrombosis and
pulmonary embolism
• An earlier return of gastrointestinal function after
abdominal surgery
• Reduction in mortality and serious morbidity post-
operatively.
There are, however, several complications that may arise
following epidural analgesia:
1. Cardiovascular. The LA causes a sympathetic block,
which can result in hypotension due to peripheral vaso-
dilatation. If the cardiac sympathetic fibres (T1-T4) are
involved, this can cause bradycardia and reduced con-
tractility. This obviously causes reduced cardiac output
and further contributes to hypotension.
2. Respiratory. Motor blockade of the intercostal
muscles causes respiratory depression, and may cause res-
piratory arrest. Epidural morphine can cause late onset
respiratory depression (up to 24 h after administration), as
it is the least lipophilic of the epidural opioids and hence
takes the longest time to diffuse through the dura mater.
3. Dural puncture. This may be caused by the epidural
needle or catheter and, if not recognized, can result in
extensive or total spinal block, which may require cardio-
respiratory support. Leakage of CSF at the puncture site
can lead to 'postdural puncture headache".
4. Infection. This is uncommon but can result in menin-
gitis; thus strict asepsis during epidural insertion by the
anaesthetist is mandatory.
5. Spinal haematoma. This is a rare but potentially dev-
astating complication. It may occur spontaneously or be
triggered by antiplatelet or anticoagulation therapy.
354
MANAGEMENT OF POSTOPERATIVE PAIN
35
Although it is difficult to determine the incidence rate
accurately, a rate of 1 / 150 000 for epidurals and 1 /220 000
for spinals has been quoted. This risk increases if there is
a haemostatic abnormality or there has been difficulty
with needle insertion (87% of reported cases of spinal
haematoma had one of these problems). The signs and
symptoms of spinal haematoma are:
a. Increasing motor block
b. Increasing sensory block
c. Back pain.
If spinal haematoma is suspected, an urgent CT or MRI
scan and a neurosurgical opinion must be obtained. If a
haematoma is present, a laminectomy is required to
decompress the spinal cord and prevent or limit perma-
nent neurological damage. (Note that epidural abscess
presents in a similar fashion, with the additional signs of
fever and a raised white cell count. Investigation and
management are similar to those for spinal haematoma.)
Key point
• Successful acute pain management with
epidural catheters requires regular assessment
of the patient to detect signs of any
complications early. Large audits of closely
supervised epidural analgesia show the safety
of the technique to be equivalent to traditional
analgesic methods when coordinated by an
acute pain service, with appropriate patient
observations and monitoring.
Epidurals and thromboprophylaxis. Patients at
risk of venous thrombosis postoperatively often require
regular subcutaneous injections of heparin. Although
unfractionated heparin is still used, there is a growing
move towards the use of low molecular weight heparins
(LMWH), e.g. dalteparin and enoxaparin. Guidelines
have therefore been drawn up to deal with the obvious
safety issues regarding the siting and removal of epi-
dural catheters in these patients. It is imperative that the
nursing and medical staff caring for the patient are aware
of these recommendations:
• Low dose (unfractionated) heparin. Following administra-
tion of low dose heparin, there should be a minimum
of 4 h before the epidural is sited. A minimum of 1 h is
recommended following the siting, or removal, of an
epidural catheter before low dose heparin is given.
• LMWH. An interval of 10-12 h is required after LMWH
before performing epidural blockade. The recom-
mended interval between epidural blockade and
giving LMWH is 4 h. This 4 h interval also applies to
catheter removal.
It is accepted that aspirin and NSAID therapy per se do not
increase risk, but in combination with low dose heparin or
the increasingly used low molecular weight heparins, the
risk of spinal haematoma may potentially increase.
A caudal epidural is a single shot epidural injection via
the sacral hiatus (sacrococcygeal membrane), which can
be used to provide perineal analgesia for a limited
period. It is most commonly used in children for post-
operative pain relief after circumcision, and for some
gynaecological procedures.
Spinal analgesia
Local anaesthetic drugs with or without an opioid may be
administered intrathecally as a 'single shot" spinal injec-
tion. An opioid such as morphine or diamorphine may
provide useful postoperative analgesia for up to 12-24 h.
Side-effects and complications are similar to epidural
analgesia. Intrathecal (spinal) catheters are available, but
owing to some case reports of cauda equina syndrome
and arachnoiditis, they are not widely used in the UK.
Methods of treating postoperative
pain
• Preoperative patient counselling and
education.
• Administration of opioids by various routes.
• Wound infiltration and regional blockade with
local anaesthetics.
• Non-steroidal anti-inflammatory agents.
Pre-emptive analgesia
A hypothesis exists that surgery, which produces a
barrage of pain signals to the spinal cord, is a 'priming'
mechanism which sensitizes the central nervous system.
This is said to lead to enhanced postoperative pain. The
rationale behind several studies is that, by providing
presurgery, or pre-emptive, analgesia using parenteral
opioids, regional blocks or NSAIDs, either individually or
in combination, these sensitizing neuroplastic changes
can be prevented within the spinal cord, leading to dimin-
ished postoperative analgesic requirements. Therefore the
concept of pre-emptive analgesia may have implications
in reducing not only acute postoperative pain, but also
chronic pain states such as post-thoracotomy chest wall
pain and postamputation lower limb stump pain. Taken
to an extreme, a single dose of analgesic drug adminis-
tered before surgery could theoretically abolish post-
operative pain. Unfortunately, no current study proves
the existence of pre-emptive analgesia in humans.
365
35 "•
POSTOPERATIVE
Specific patient groups
Day surgical patients
The ability to perforin increasingly complex surgery on
a daycase basis highlights the need for appropriate
screening, selection, preoperative preparation, treat-
ment and discharge of these patients. The brevity of the
patient's hospitalization and contact with healthcare
professionals make adequate pain management a par-
ticular challenge.
Pharmacological options for postoperative analgesia
include opioids, NSAIDs and local anaesthetics. Try if
possible to prescribe opioids with shorter half-lives, to
avoid side-effects which may delay discharge from
hospital. The use of NSAIDs may reduce postoperative
opioid requirements and offer a better tolerability profile,
and is highly recommended after ambulatory surgery.
The use of LA drugs in laparoscopic surgery, e.g. in
wound infiltration or intraperitoneally at the time of oper-
ation, is also effective in the treatment of postoperative
pain, and can produce a prolonged analgesic effect. Once
again, multimodal analgesia has been shown to be more
effective in day surgical patients than any of these agents
administered alone.
Elderly patients
When treating pain in the elderly, you must appreciate
their generally reduced reserve and high incidence of
concomitant disease and polypharmacy. Use NSAIDs
with caution, as the elderly have an increased incidence
of gastric and renal toxicity. Consider coadministration of
a proton pump inhibitor (e.g. omeprazole) if gastric
ulceration is of particular concern. Opioids are effective,
with patients experiencing a higher peak and longer
duration of pain relief, but remember that these patients
are more sensitive to sedation and respiratory depression
- probably as a result of altered drug distribution and
excretion.
Key point
• Titrate opioid dosage carefully in the elderly to
take into account analgesic effects and
side-effects, including possible cognitive
impairment.
Children
Preparation of the patient starts at home, as psychologi-
cal support may decrease anxiety and fear of surgical
procedures. The presence of parents or carers in the
anaesthetic room decreases postoperative pain and
reduces the risk of adverse psychological sequelae. Make
sure that drugs are given by the least painful route, and
analgesic efficacy is assessed at regular intervals. It has
been clearly demonstrated that children as young as
5 years old can understand the principles and workings
of a PCA device.
Opioid tolerance and addiction
Tolerance describes the decrease in efficacy of a drug as a
result of its previous administration. This is manifest as a
high requirement for opioid analgesia and relative
resistance to side-effects. Patients taking chronic opioid
therapy require significantly increased doses of opiate in
the acute situation. If the oral route is available, continue
chronic oral opiates, with parenteral supplementation as
required. Use non-opioid alternatives, if at all possible, as
adjuncts or even as sole therapy.
Key point
• Surgical review is warranted if opioid
requirements appear to increase rapidly, in
order to rule out any surgical complication.
Opioid addiction is unlikely to occur following the use of
opioids for postoperative pain in opioid naive patients.
However, when treating patients with known opioid
dependence or addiction it is important to realize that
pain-scoring systems are unreliable. In patients still
using opioids, PCA may be advantageous, as it allows
the use of high doses of opioids and may reduce con-
frontation with staff members. Background infusions are
a reasonable way of delivering the patient's daily
requirement. Non-opioid therapies should always be
considered, and epidural analgesia can be valuable after
major surgery. In the reformed addict there is significant
onus on clinical staff to avoid re-establishing depen-
dency. Patients in this category presenting for major
surgery are a particular challenge, but make every effort
to avoid opioids without subjecting the patient to
unrelieved pain.
MONITORING OF POSTOPERATIVE
ANALGESIA
ft^;#:&*&frm^S^^
The effectiveness of any postoperative analgesic regimen,
as well as any side-effects, needs to be assessed regularly.
Ensure that the patient is monitored regularly to deter-
mine the level of pain, sedation and respiration.
366
MANAGEMENT OF POSTOPERATIVE PAIN
35
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Monitoring of pain
The simplest method of monitoring pain is through obser-
vation of the behaviour of the patient, for example the
time taken for the patient to sit or stand or the ability of
the patient to cough. You can also monitor the analgesic
requirements of the patient (e.g. the total dose of analge-
sia administered over a 24 h period or the number of
demands of a PC A pump). Physiological measures such as
heart rate and blood pressure may also increase in the
presence of pain, but these parameters at best simply
improve the discriminatory power of other measures.
However, patient self-report is the most reliable and valid
measure of pain in the clinical situation, and this is usually
done using unidimensional scales, as illustrated (Fig. 35.2).
Pain scores can be difficult to interpret because indi-
vidual patients vary in their perception of pain. The
verbal rating scale (VRS) and visual analogue scale (VAS)
are the most commonly used methods when adjusting
Unidimensional measures of pain Intensity
Verbal rating scale
The patient rates the pain verbally (e.g. none, mild,
moderate or severe)
Numerical rating scale
The patient rates pain on a scale typically from
(no pain) to 10 (severe pain)
2 i 3
4 S
6 7
8
No pain
To]
Severe pain
Visual analogue scale
The patient indicates intensity of pain on a line typically
10cm long marked from no pain' at one end to severe
pain f at the other end. The pain is then scored in cm or
mm, often with a sliding marker to aid measurement
No pain
Severe pain
Faces scale
The child indicates which face represents how much
pain they have. Clearly this may measure other factors
such as general distress rather than pain exclusively
No pain
Severe pain
analgesic regimens such as opioid PCA or epidural
infusions. Most pain scores only measure pain when the
patient is resting. Obviously such a score will change
when, for example, a patient after upper abdominal
surgery attempts to cough to clear secretions or receives
chest physiotherapy. Therefore pain scores on coughing
or moving will be just as important as those at rest.
Monitoring of sedation and respiration
The major fear with opioids, administered by any route
(intravenously, intramuscularly or epidurally) is that of
respiratory depression. Epidural opioids have the added
risk of delayed respiratory depression. This risk is
extremely small. Highly lipid-soluble opioids such as fen-
tanyl have a lower risk of this complication, administered
epidurally, than does morphine, which is less lipid
soluble. Of course you must also consider the general
medical condition of the patient, as elderly patients with
cardiorespiratory disease are at a higher risk of this poten-
tially dangerous complication. Traditionally it has been
assumed that intermittent observation of a patient's
respiratory rate by a ward nurse is adequate to detect
respiratory problems. It should be noted, however, that a
decrease in respiratory rate has been found to be a late and
unreliable indicator of respiratory depression. Sedation is
a better indicator and all patients receiving opioids should
be monitored using a sedation score, for example:
= None
1 = Mild, occasionally drowsy, easy to rouse
2 = Moderate, constantly or frequently drowsy, easy to
rouse
3 = Severe, somnolent, difficult to rouse
S = Normal sleep
Key point
Fig. 35.2 Commonly used pain scales.
• A sedation score of 3 or respiratory rate less
than 8 breaths per minute should be treated
immediately with intravenous naloxone.
The development of pulse oximetry, which allows a
patient's blood oxygen saturation (Sp0 2 ) to be measured
non-invasively using a simple finger probe, is already a
minimum monitoring standard during anaesthesia and
the immediate recovery period. Several studies, which
have extended the use of pulse oximetry to the postoper-
ative period on the ward, have detected periods of hypox-
aemia 3-4 days after major surgery. The relationship of
these events to the risk of myocardial ischaemia is a
subject of ongoing research.
367
35
POSTOPERATIVE
Key point
If using pulse oximetry, treat an Spo 2 of less
than 94% in a patient breathing air with
supplemental oxygen through nasal prongs or
a face mask.
POSTOPERATIVE NAUSEA AND
VOMITING (PONV)
The vomiting centre is found in the reticular formation of
the medulla. It receives afferent impulses from various
pathways, including the chemoreceptor trigger zone
(CTZ). This area is located within the floor of the fourth
ventricle and is activated by various stimuli (Fig. 35.3).
Risk factors associated with postoperative nausea and
vomiting include:
• History and examination
- Past history of PONV
- History of motion sickness or migraine
- Prolonged starvation
- Recent oral intake
- Obesity
- Female sex
• Type of surgery
- Gastrointestinal
- ENT/ophthalmic
- Gynaecological
- Orthopaedic
- Emergency
• Drugs, e.g. thiopentone, opioids.
A number of general measures may be employed in the
treatment of PONV, including:
• Hydration and maintenance of adequate blood
pressure
• Avoiding excessive movement in the immediate post-
operative phase
• Reducing the patient's anxiety.
The following agents may be useful in treating PONV:
• Anticholinergic agents, e.g. cyclizine/hyoscine
• Antidopaminergic agents, e.g. domperidone and
metoclopramide
• 5-HT3 antagonists, e.g. ondansetron.
Oropharyngeal &
Gut stimulation
Raised intracranial pressure
Hypotension Migraine
VOMITING CENTRE
(trans m itter : acety Ichol i ne)
Hyoscine / Cyclizine
-4 Vestibular stimulation
<4 Pain
CTZ
(transmitter: dopamine, 5-HT)
Domperidone, Ondansetron,
Metaclopramide
Hypoxaemia
Anaesthetic drugs
Opioid drugs
Fig. 35.3 Management of postoperative nausea and vomiting.
368
MANAGEMENT OF POSTOPERATIVE PAIN
35
ACUTE PAIN SERVICE (APS)
^^^^^■^
An anaesthesia-based multidisciplinary team approach to
acute pain relief was first described by Ready in Seattle,
USA. In 1990 the Royal College of Surgeons of England and
the Royal College of Anaesthetists recommended that each
hospital should have an APS team. The establishment of an
APS requires medical, nursing and pharmaceutical exper-
tise. Anaesthetists have a major role to play, as they not only
initiate postoperative analgesic regimens, such as PCA and
epidural infusions, but are also familiar with the drugs and
equipment used in such cases. Many hospitals have an
acute pain team consisting of a dedicated pain nurse, con-
sultant anaesthetist and sometimes junior anaesthetic staff.
The role of the acute pain team includes:
• Devising, implementing and auditing pain protocols
• Reviewing patients in whom postoperative analgesia is
proving difficult
• Reviewing patients with epidural and intravenous
infusions
• Managing patients with chronic pain.
CONCLUSION
■£ v j£?V£* '&?■& ■ ; ■ j'&?&&i?i& £&3i >'?^i^'^:^yM^J^'^'^f>ft^Ji;
■f^^iT^^M^^^M^&^i^'^^^^
'&&''$*&£'*& S^jfe J;
Currently, in the treatment of postoperative pain, there is
no single analgesic therapy that can treat all aspects of
pain without causing side-effects. The emphasis should
be on a 'balanced analgesic' technique, especially after
major surgical procedures, using NSAIDs in combination
with other drugs such as opioids or local anaesthetics.
The future of acute pain management lies in better edu-
cation of healthcare staff, universal introduction of pain
scoring and improved use of existing facilities. The chal-
lenge lies in disseminating knowledge and expertise to
ensure that best practice is adopted universally.
Summary
• Pain can be treated by various methods
which affect the transmission of a painful
stimulus at different levels along its
pathway to the central nervous system.
Treatment of pain may reduce the incidence
of some postoperative complications and
hence reduce hospital stay.
Opioids, given i.v. or i.m. remain common
analgesics for the treatment of
postoperative pain. Regional blockade
using a low dose combination of local
anaesthetic and opioid is also now
popular. The concurrent use of NSAIDs is
useful in reducing opioid requirements.
The degree of analgesia and sedation
must be carefully monitored on the ward.
In most hospitals an acute pain service is
available to advise on the methods
available for the treatment of postoperative
pain and potential complications associated
with such methods.
Further reading
1998 Guidelines on the use of NSAIDs in the perioperative
period. Royal College of Anaesthetists, London
Liu S, Carpenter RL, Neal JM 1995 Epidural anesthesia and
analgesia, their role in postoperative outcome.
Anesthesiology 82: 1474-1506
Lumley JSP, Craven JL (series eds) 2001 Pain, Anaesthesia and
Intensive Care Medicine 2(11).
McQuay HJ 1992 Pre-emptive analgesia. British Journal of
Anaesthesia 69: 1-3
National Health and Medical Research Council 1999 Acute pain
management: the scientific evidence. NHMRC, Canberra
Ogilvy AJ, Smith G 1994 Postoperative pain. In: Nimo WS,
Rowbotham DJ, Smith G (eds) Anaesthesia. BlackweU,
Oxford, pp 1570-1602
Rawal N 2002 Editorial: Acute pain services revisited - good
from far, far from good? Regional Anaesthesia and Pain
Medicine 27: 117-121
Ready LB 1 990 Acute postoperative pain. In: Aitkenhead AR,
Smith G (eds) Anesthesia, 3rd edn. Churchill Livingstone,
Edinburgh, pp 2135-2145
Rowbotham DJ 1994 Gastric emptying, postoperative nausea
and vomiting and antiemetics. In: Nimo WS, Rowbotham
DJ, Smith G (eds) Anaesthesia, BlackweU, Oxford,
pp 350-371
Sabanathan S 1995 Has postoperative pain been eradicated?
Annals of the Royal College of Surgeons 77: 202-209
369
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371
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Complications: prevention
and management
J. A. R. Smith
w
Objectives
Accept that complications are best
anticipated and avoided.
Recognize the incidence of comorbidity.
Understand the importance of matching
the procedure to the associated risks.
Appreciate the importance of recognizing
complications early and treating them
vigorously.
Table 36.1 Risk of cardiovascular disease with age
RISK FACTORS
• General - applicable to all procedures, or
• Specific to the operation and /or the complication
concerned.
Old age
In older age, some conditions are encountered more
commonly:
1. Neoplastic conditions.
2. Peripheral and cardiovascular disease. The inci-
dence of cardiovascular disease rises with age (Table 36.1)
and this is associated with an increased risk of postoper-
ative myocardial infarction. Over age 50 years the risk is
6%, with a 70% mortality rate. There is also an increased
incidence of atrial fibrillation and hypertension and
therefore of serious dysrhythmia and death.
3. Respiratory disease. Several changes occur in the
elderly. These include reduced arterial oxygen tension,
especially over 80 years of age. There are also: increased
physiological dead space; decreased lung capacity, vital
capacity, maximal breathing capacity, forced expiratory
volume and peak expiratory flow rate.
4. Renal function deteriorates with age because of
peripheral vascular disease, loss of nephrons, and
impaired cell function. Therefore fluid overload and dis-
turbance of both acid-base and electrolyte balance are
more common in the elderly.
Age
(years)
Incidence of
cardiovascular disease {%)
40-50
G
60-70
41
70-80
100
5. Medication. Elderly patients are more likely to be on
regular medication for a number of disorders. The risk of
drug interaction is therefore increased.
Neonatal period
At the other end of the age spectrum, neonatal surgery is
also hazardous:
1. Tolerance of intravenous fluids is poor.
2. Gastrointestinal losses by vomiting and diarrhoea
are common and can be life threatening. There is
increased susceptibility to disturbance of acid-base
balance, and accurate replacement of fluid and elec-
trolytes and correction of disturbance of pH is much more
difficult.
3. Thermal regulation is poor, resulting in an increased
risk of hypothermia. Enzyme systems are immature, so
that jaundice is more common, and both general and drug
metabolism may be impaired.
4. Congenital abnormalities are often multiple and
major, and surgery is more demanding because of the
physical size of the patient and the delicacy of the tissues.
Obesity
Patients may be overweight (up to 10% above their ideal
bodyweight), obese (10-40% above) or morbidly obese
(more than 40% above their ideal).
Anaesthetic difficulties include difficulty in intubation
and in the placement of intravenous lines. Chest wall
compliance is reduced, with consequent difficulties with
ventilation. Positioning the patient on the operating table
373
36 .
COMPLICATIONS
while avoiding pressure injuries requires considerable
skill. In morbidly obese patients, cardiomyopathy and
respiratory dysfunction may be severe enough to be life
threatening. In some series, mortalities of 10-25% because
of anaesthetic risks alone have been reported.
Surgery is complicated by technical difficulties; these
can include limited exposure, adipose tissue obscuring
the view and making trauma to associated structures
more likely and problems in minimally invasive surgery
because of difficulty in gaining access to the peritoneal
cavity.
In addition, blood vessels are less well supported and
tend to retract if divided. Control of haemorrhage is there-
fore more difficult and haematoma formation more
common. As a consequence, wound infection and
impaired wound healing are encountered more often. The
risk of venous thromboembolism is increased because fat
patients tend to be less mobile, their weight exerts greater
pressure on the calf veins during surgery, and there is an
increased likelihood of endothelial trauma. In some obese
patients there is an association with atherosclerosis and
therefore with peripheral vascular disease.
In orthopaedic practice, obesity increases the incidence
of arthritis, makes joint replacement more difficult from a
technical view point and places an extra strain on lower
limb prostheses. Indeed, such patients may require
bariatric surgery, such as vertical banded gastroplasty, to
allow weight loss before joint replacement. A reduction of
between 50 and 75% of the excess body weight over
12 months can be anticipated.
Table 26,2 Risk of myocardial infarction with time
MP
Key point
• There is no scientific evidence that weight
reduction is rewarded by a reduction in the
incidence of postoperative complications.
Cardiovascular disease
Myocardial infarction. A recent infarct is the most
serious predisposing factor (Table 36.2). The more recent
the infarct, the greater the risk of a further infarct. The risk
remains higher than normal even after an interval of
3 years. The mortality from recurrent infarcts is also time
related, being 75% in the first 6 months and falling to 25%
after 1 year. Therefore, defer operations with a low risk of
morbidity and mortality for at least 6 months post infarct.
Angina. The severity of angina dictates the risk of
cardiovascular complications in general and myocardial
infarction in particular.
Dysrhythmias. Dysrhythmias such as atrial fibrilla-
tion and heart block carry the worst prognosis. Correction
Time since infarct
Incidence of further
infarction after surgery (%)
0-6 months
55
1-2 years
22
2-3 years
6
>3 years
No infarct
1
0,66
of the dysrhythmia reduces but does not abolish the risk
of cardiovascular complications.
Cardiac valve disease. The presence of an artificial
valve causes a major risk of bacterial colonization follow-
ing surgery. Administer prophylactic antibiotics for all
procedures. Mitral valve disease increases the risk of
atrial fibrillation and of atrial thrombosis. Significant
valve disease impairs cardiac responses to surgery and to
infused fluids.
Cardiac pacemakers. These are 'foreign bodies',
therefore administer prophylactic antibiotics. If a pace-
maker is at a fixed rate, an inability to increase heart rate
renders the patient vulnerable to hypovolemia. Take care
when using diathermy, especially if it is unipolar.
Atherosclerosis. The incidence of atherosclerosis
tends to increase with age, e.g. at age 50 the incidence is
23% with a 0.7% risk of myocardial infarction, while at
age 70 the incidence of arteriosclerosis is 100%. The risk
of cardiovascular complications shows a similar pattern
to the incidence of atheroma.
Hypertension. This does not increase the risk of
myocardial infarction in abdominal surgery, but there is
an increased risk as a result of cardiac surgery. Remember
that surgery for phaeochromocytoma, and sometimes for
carcinoid disease, can be associated with wide fluctu-
ations in blood pressure. This increases the risk of cerebral
vascular accident.
Key points
The combination of respiratory and
cardiovascular disease is more serious than one
of them alone. A combination results in arterial
hypoxaemia and is more common in older
patients.
If renal function is also impaired, the risk of
fluid overload is greatly increased.
A normal myocardium can compensate well
down to a haemoglobin level of 10 g dM.
Below this level, or if there is myocardial
374
COMPLICATIONS: PREVENTION AND MANAGEMENT
36
disease, peripheral hypoxaemia is more likely.
Even at this level, subendocardial ischaemia
and fibrosis may occur.
nidus for infection. Where diabetes is poorly controlled
there may be a higher sugar level in blood and tissues;
this also encourages bacterial growth.
Respiratory disease
There is an increased risk of respiratory complications in
smokers / in patients with bronchiectasis and emphysema,
and if surgery is undertaken in the presence of tonsillitis,
bronchitis or even coryza (Greek kara = head + zeein = to
boil; a head cold). In this group postpone elective surgery
until the infection has cleared.
As indicated above, with advancing years there is a
reduction in arterial oxygen tension and various changes
in lung physiology. This results in a greater difference in
alveolar-arterial oxygen tension and thus any respiratory
complication produces more severe hypoxaemia.
e
Key point
• A combination of cor pulmonale and ischaemic
heart disease produces a mortality of about
50%.
Diabetes mellitus
Insulin-dependent diabetics are high risk patients for a
number of different reasons.
Metabolic factors
The metabolic response to surgery results in hypergly-
caemia. Maintenance of blood sugar can be difficult in the
perioperative period and even non-insulin-dependent
diabetics may require insulin for a short time. If compli-
cations such as infection arise, both hyperinsulinaemia
and hyperglycaemia may coexist - so called insulin resist-
ance. The major danger is the development of severe
ketoacidosis. This is seen most commonly in poorly con-
trolled diabetic patients, or indeed in those who are pre-
viously undiagnosed. Remember that one presentation of
diabetic ketoacidosis is as an 'acute abdomen 7 . It is always
sensible to measure blood and urinary glucose in all
patients with abdominal pain.
Infection
In diabetes mellitus, polymorphonuclear phagocyte func-
tion is impaired. There is an increased incidence of
peripheral vascular disease affecting both medium and
small vessels. Diabetic neuropathy reduces sensation to
touch and to pain. Skin ulceration commonly acts as a
Wound healing
The disease in medium and small vessels reduces blood
supply to healing tissue. The impaired polymorph phago-
cyte function interferes with the acute inflammatory reac-
tion. As described, there is an increased risk of infection.
All of these factors contribute to impaired wound healing.
Peripheral vascular disease
The increased risk of atheroma affecting both medium
and small arteries increases the risk of gangrene.
Neuropathic ulcers are more common. If infection does
occur in the presence of gangrene, wet gangrene is more
likely to be encountered.
Renal disease
If diabetes mellitus has been present for 20 years there is
a 15% incidence of glomerulosclerosis. This impairment
of renal function makes fluid and electrolyte balance more
complex. Diabetic patients are more sensitive to protein
depletion, and are at increased risk of severe ketoacidosis
during a surgical illness.
drug™ef^
Antibiotics
Misuse of antibiotics is said to be a major cause of litiga-
tion in the USA. Anaphylactic reactions are rare but can
be life threatening. Hypersensitivity reactions, however,
are slightly more common and only marginally less
serious. Ask about drug allergy during the systematic
enquiry of every patient.
Misuse of antibiotics may result in the development of
resistance. The most serious from the point of view of the
patient and the surgical department is the methicillin-
resistant Staphylococcus aureus (MRS A). It is important to
have a hospital antibiotics policy, with clear indications
for the use of antibiotics. Use them for a specific period
only and take advice from the microbiologist for complex
infections or immunocompromised patients.
The risk of MRSA infection in healthy individuals is
very small but to ill patients in hospital can be life threat-
ening. Isolate patients who have bacteriological evidence
of MRSA infection and barrier nurse them. In patients
who are unwell, administer appropriate antibiotic
therapy according to advice from the microbiologist.
375
3il
COMPLICATIONS
Pseudomembranous colitis
This may present as a surgical emergency. Exposure to
antibiotics combined with a period of hypovolaemia or
hypotension are joint factors in pathogenesis. Diagnosis is
made on the basis of a frozen section biopsy taken at sig-
moidoscopy and confirmed by the demonstration of the
Clostridium difficile toxin in the faecal fluid. Intravenous
vancomycin or metronidazole are usually effective in
treatment. Occasionally total colectomy is required for
resistant cases.
Aminoglycocides
Gentamicin causes ototoxicity in 3% of patients. The
elderly and those with impaired renal function are at
increased risk. It causes nephrotoxicity in 2% of patients.
For that reason monitor peak and trough blood levels in
all patients receiving this therapy.
Corticosteroids
The greatest risk of complications occurs in patients on
high dosage or on long courses of therapy.
Corticoids act to interfere with the mobility and phago-
cytic activity of polymorphonuclear leucocytes. This means
that acute inflammation and the handling of bacteria are
impaired, including the inflammatory reaction which is an
essential part in the repair of wounds. Therefore deficient
wound healing and wound infection are more common.
The production of ground substance is reduced.
Therefore capillary fragility is increased and wound
haematoma is more common. This contributes to impaired
wound healing and also provides a nidus for infection.
Note, however, that in experimental circumstances the
short term use of methylprednisolone has not been asso-
ciated with impaired healing of colonic anastomoses.
Stress response
Steroid therapy within the 6 months before surgery
depresses the endogenous production of glucocorti-
coids. The output of endogenous glucocorticoid is an
essential part of the response to surgery and anaesthesia.
In order to avoid this complication the patient should
receive 100 mg of hydrocortisone intravenously at the
induction of anaesthesia and at 6-hourly intervals for
48 h. Over the next 5-7 days reduce the intake of gluco-
corticoid either to zero or to the preoperative level.
Delay in diagnosis
Because of the depression of the acute inflammatory
reaction, steroid therapy may delay the diagnosis of
postoperative complications. It may also render some
complications more likely to occur. For example, if a
peptic ulcer perforates in someone on steroid therapy the
diagnosis may be delayed, with resulting increase in
morbidity and mortality.
There is some evidence that glucocorticoids in
dosages used for immunosuppression may encourage
the development of certain virally induced tumours. In
transplant patients there is evidence that the incidence
of head and neck tumours and the virally induced
tumours may be increased. This has not been reported in
more common tumours of lung, breast or gastrointesti-
nal tract.
Orthopaedic practice
Patients who are on steroid therapy in general, and those
on steroids for rheumatoid arthritis in particular, have an
increased risk of osteoporosis, which makes them more
prone to suffer pathological fractures. Joint replacement is
more difficult in such patients because of bone thinning
and because of the general complications mentioned
above.
Cytotoxic agents
Patients on cytotoxic chemotherapy have well-recognized
problems of gastrointestinal upset and hair loss.
Depression of the white cell count and white cell function
interfere with acute inflammation. This produces an
increased incidence of wound infection and of impaired
wound healing. Bone marrow depression is common. This
also increases the risk of infection, especially with oppor-
tunistic organisms. It also risks purpuric eruption and
frank bleeding. The expected reduction in cell-mediated
immunity increases the risk of developing a second neo-
plasm; for example, in patients successfully treated for
primary lymphoma there is a 3% risk of a second tumour
developing.
Ciclosporin
Ciclosporin A carries all the risks of depressing immune
responses. More specifically it can result in depression of
renal function. This is the usual reason for having to dis-
continue therapy with this agent.
BLOOD TRANSFUSION
Incompatibility
Major incompatibility reactions are now rare, even with
emergency crossmatching. Minor group incompatibility
376
COMPLICATIONS: PREVENTION AND MANAGEMENT
is more common, especially in patients who have had
repeated transfusions. This involves, in order of import-
ance, the Kell, Duffy or Kidd systems. It is common to
attribute febrile reactions to incompatibility. Remember
that transfusion of pyrogens or antibodies to white cells
are alternative explanations for a febrile reaction.
Consequences of storage
The lifespan of red cells is finite and therefore lysis is an
inevitable consequence of storage. This may produce
transient jaundice but is not of dire consequence. More
importantly there is a potential for hyperkalemia after
massive blood transfusion because of the release of the
intracellular potassium ion. Careful monitoring of such
patients by regular assessment of urea and electrolytes
and of ECG changes, which begin to occur above a level
of 6 mmol 1"\ are essential.
Acid citrate dextrose
This is the most commonly used anticoagulant.
Transfused citrate may bind free calcium, resulting in
hypocalcaemia. Careful monitoring of the ECG is essen-
tial. Both platelets and clotting factors are consumed
within some hours of storage. As a consequence, trans-
fused stored blood cannot be relied upon to correct haem-
orrhagic tendencies and transfusion of fresh platelets or
fresh frozen plasma may be required.
Oxygen carriage
The level of 2,3-diphosphoglycerate falls in stored red
cells. This produces a shift of the oxyhaemoglobin dis-
sociation curve to the left, resulting in an increased affin-
ity of haemoglobin for oxygen. Delivery of oxygen at
tissue level is therefore reduced. Stored red cells become
more rigid. This impairs capillary circulation and encour-
ages sludging.
Transmission of disease
In the past, both syphilis and hepatitis B were transmit-
ted by transfusion (see Ch. 21). These diseases have been
virtually abolished by stringent screening methods.
Hepatitis C remains a significant risk in some countries
where screening is not well established. Earlier serologi-
cal tests were unsatisfactory but more specific immuno-
logical tests, such as immunoblotting, are now available.
In Britain most case of hepatitis C are associated with
drug abuse. More recently, the human immunodeficiency
virus (HIV) has been transfused, mainly to haemophilic
patients, with disastrous consequences.
Alteration in immunity
In transplantation surgery it is clear that the risk of renal
rejection is reduced after blood transfusion. In patients
undergoing resection for colonic cancer, perioperative
transfusion results in a poorer prognosis, even when
groups are matched for stage of disease, degree of oper-
ative trauma, age, sex and other factors. This is attributed
to a reduction in cell-mediated immunity. Other neoplas-
tic processes and the relevance of blood transfusion to
prognosis remain under investigation. In colorectal
surgery, the use of blood transfusion is also associated
with an increased risk of infective complications in the
postoperative period. This risk has not been identified in
patients undergoing joint replacement in orthopaedic
practice.
Obstructive jaundice
1. Effect on coagulation. Patients with obstructive jaun-
dice have an increased risk of haemorrhage in the peri-
operative period. The absorption of the fat-soluble
vitamin K is impaired in the absence of bile salts. This
interferes with the production of the vitamin K-dependent
factors II, VII, IX and X. The liver manufactures most clot-
ting factors and therefore back pressure from obstruction
may interfere with the synthesis of these factors and also
factors V, XI, XII and XIII. The liver also clears activated
coagulation factors such as fibrin degradation products
(FDPs). When there is severe impairment of liver function
there may also be disseminated intravascular coagulation.
All patients with obstructive jaundice should have a
full clotting screen. Depending on the results of that
screen, patients should be given systemic vitamin K a
and /or fresh frozen plasma. The intravenous route for
vitamin K T is recommended because it reduces the risk of
intramuscular haematoma.
2. Effect on wound healing. Back pressure interferes with
hepatocellular function and therefore disturbs protein
metabolism. There is clear evidence that where obstructive
jaundice is due to a malignancy there is impairment of
healing of wounds and anastomoses. It is also taught that
the same problem occurs in all patients with obstructive
jaundice. The evidence for this is less clear. However,
sufficient doubt remains for all patients with obstructive
jaundice to be considered at high risk of wound failure.
As already indicated, an increased incidence of wound
haematoma and infection will also interfere with wound
healing.
3. Effect on infective complications. Stasis within the
biliary system increases the risk of infection, particularly
377
36
COMPLICATIONS
with Gram-negative organisms. It is well established that
opening the common bile duct produces a threefold
increase in the incidence of wound infection relative to
cholecystectomy alone. Where obstructive jaundice is sec-
ondary to stones or to postoperative stricture, the inci-
dence of infected bile is at least 75%. With malignant
obstruction, incidences of infection of 25% have been
reported. The more often the bile duct is operated upon,
the more likely there is to be infected bile with a conse-
quent increase in postoperative infective complications.
The whole picture is complicated by the fact that there
is reduced efficacy of the reticuloendothelial (Kupffer)
cells in the liver. In the presence of infected bile there is an
increased incidence of septicaemia, but also an increase in
the production of endotoxins. Furthermore, there is a poss-
ibility of translocation of bacteria from the small bowel.
This combination may overcome the capacity of the retic-
uloendothelial system. The result is increased mortality
and morbidity, particularly from ascending cholangitis.
This means that the incidence of septicaemia and endo-
toxinaemia is increased. Increased mortality and morbid-
ity result, particularly from ascending cholangitis.
4. Effect on renal function. Following surgery for
obstructive jaundice, patients are at risk from acute renal
failure - the 'hepatorenal syndrome'. There are a number
of theories as to aetiology.
Acute renal failure is also a. complication of Gram-
negative septic shock, believed to be caused by the effects
of endotoxins. The effects include activation of comple-
ment by the alternative pathway, the release of a number
of cell mediators, including tumour necrosis factor and
interleukins, and inappropriate disseminated intravascu-
lar coagulation (DIC). DIC results in microthrombi being
found in the renal parenchyma, thus interfering with
renal function.
It is also said that at least some part of renal failure
occurs because the tubules are blocked by excess biliru-
bin. Histological evidence of this is variable and, at most,
it is likely to be no more than a contributing factor.
The hormones responsible for maintaining fluid and
electrolyte balance, such as antidiuretic hormone (ADH),
aldosterone and natriuretic factors, are metabolized in the
liver. Disturbance of hepatic function may interfere with
the activities of these hormones. Because of the increasing
problems of haemorrhage, patients with obstructive jaun-
dice are at greater risk of hypovolemia. Protection
against the effects of obstructive jaundice on renal func-
tion are to ensure adequate perioperative fluid infusion
and a good diuresis, e.g. by the use of the osmotic diuretic
mannitol. Give prophylactic antibiotics.
5. Effects on drugs and metabolism. It is assumed that
general drug metabolism is altered in the presence of
obstructive jaundice. The evidence in support of this is
not strong. However, a particular problem does arise for
drugs which are oxidized in the liver. In surgical practice
great caution is required with analgesic and sedative
therapy with, for example, morphine-like agents.
6. Take note of the specific problems relating to
warfarin and the interference with the International
Normalized Ratio (INR) produced by certain antibiotics.
Neoplastic disease
Venous thromboembolism
The association between superficial thrombophlebitis
migrans and pancreatic carcinoma is well established.
However, it seems likely that malignant tumours secrete
factors, such as thromboplastins, which affect the throm-
botic cascade. In general terms, oncological procedures
tend to be prolonged, they are associated with greater
operative trauma, and they often require blood transfu-
sion; all of this increases the incidence of deep vein
thrombosis. Both in urology and in gynaecology, major
procedures in the pelvis are at particular risk of this com-
plication. In addition to the factors mentioned above,
pressure on the iliac veins is a significant problem.
Wound healing
It is generally accepted that patients with carcinoma are
at increased risk both of primary wound failure and later
incisional herniation. This relationship has been most
clearly confirmed in malignant obstructive jaundice. In
this condition malnutrition is combined with impaired
protein metabolism in the liver.
The whole concept of cancer cachexia is complex, and
in patients who have lost more than 10% of their premor-
bid body weight, or who present with a serum albumin of
less than 30 gl -1 , there is impaired healing both of
wounds and anastomoses.
Patients with ovarian cancer have a high incidence of
ascites with omental and peritoneal deposits. In contrast
to gastrointestinal malignancy, radical surgery in these
patients can be rewarding. However, this involves the
rapid loss of protein-rich fluid. If the ascites reaccumu-
lates rapidly in the postoperative period there will be
associated abdominal distension and leaking through the
wound. Both of these factors also impair wound healing.
TWE^OF SURGERY
Minimally invasive surgery
No field of surgical practice has escaped the introduction
of minimally invasive procedures. The picture is most
clearly established in laparoscopic cholecystectomy,
where there is evidence of more rapid recovery from
378
COMPLICATIONS: PREVENTION AND MANAGEMENT
36
surgery, earlier discharge from hospital and earlier return
to normal activities. The operation of minicholecystec-
tomy has been compared with the laparoscopic route,
with no clear benefit of the latter being proven.
The learning curve for this new form of operation can
be long. This is because hand-eye coordination is differ-
ent from conventional surgery and because the handling
of tissues at a distance means that tactile sensitivity is
reduced. Visual fields are limited, which is of particular
importance when diathermy, laser or intracorporeal
suturing are being applied. Take great care to visualize
probes and needles and to keep them within your visual
field at all times.
More recently, the concept of hand-assisted laparo-
scopic surgery has been developed. This is of particular
relevance to gastrointestinal surgery. Only time will tell
whether such a combined approach avoids some of the
problems of laparoscopic surgery, for example, radical
ablation of neoplastic disease and port-site recurrence.
A particular problem exists when diathermy is used
when capacitance coupling may occur, resulting in burn
injuries at the trocar sites. Initially there was a vogue for
the use of laser-assisted dissection; this has largely been
overtaken by diathermy. However, if you use laser, take
all the normal precautions for the use of lasers, and gain
a clear understanding of the characteristics of the differ-
ent forms of laser in current use.
With specific reference to cholecystectomy, it is clear
that there is at least a fivefold increase in the incidence of
bile duct injury in comparison with conventional surgery.
Take great care to identify the anatomy and be willing to
convert to open cholecystectomy if you encounter diffi-
culty or if your held of view is obscured.
Orthopaedic surgery
Thromboembolism
Operations on the hips and pelvis have an increased risk
of deep venous thrombosis (DVT), so prophylactic war-
farin is often administered. Recent reports have demon-
strated the value of low molecular weight heparin. The
risk is higher if surgery is performed after major trauma.
Blood transfusion also increases the risk of DVT.
Wound infection
Most orthopaedic procedures are classified as clean.
Therefore the incidence of wound infection is low.
However, the consequence of infection, for example after
joint replacement, is catastrophic. If a foreign body such
as a joint prosthesis becomes infected, the chance of
eradicating the infection by antibiotics is minimal. It is
necessary to remove the prosthesis.
Use of tourniquets
In orthopaedic surgery tourniquets are widely used and
it is recognized that tourniquet time must be kept to a
minimum. However, it is vitally important that you assess
the vascular supply, especially to the lower limbs. If you
do not, the potential hazard of, for example, knee replace-
ment is greatly increased. Remember also that skin
ischaemia may complicate badly planned incisions.
Steroid therapy
The problem with steroid therapy has already been men-
tioned. Especially in patients on steroids for rheumatoid
arthritis, surgery is more difficult and anaesthetic problems
may be faced, for example if the cervical spine is involved.
Gynaecological surgery
In operations within the pelvis, and particularly those
lasting over 45 min, there is increased risk of trauma to the
pelvic veins. This increases the risk of iliofemoral throm-
bosis. Extensive oncological eradication carries, in addi-
tion, all the risks relevant to cancer surgery (see above).
Thoracic and upper abdominal procedures
Incisions used for this type of surgery usually cause
exceptional postoperative pain. Respiratory movement
may be restricted, increasing the risk of atelectasis and
infective complications, especially in elderly patients.
Prolonged operations
Traditional teaching is that prolonged operations increase
the risk of respiratory difficulties, fluid and electrolyte
imbalance and deep vein thrombosis. Experience with
prolonged keyhole operations by the laparoscopic route
have proved them relatively free of complications. This
seems likely to be related to reducing the influence of
such factors as:
• Intraoperative trauma
• Need for blood transfusion
• Loss of fluid and heat from exposed cavities
• Minimal damage to tissues.
Key point
Prolonged time spent on the operating table
does not inevitably cause respiratory
thrombotic, fluid balance and electroyte
disturbances.
379
36
COMPLICATIONS
Remember that although the incidence of complications
may be lower in minimally invasive surgery, they are not
abolished. Deep vein thrombosis, wound infection and
wound hernia at port sites do occur. Therefore take pro-
phylactic measures and carefully monitor patients in the
postoperative period.
COMPLICATIONS AND THEIR
MANAGEMENT
Venous thromboembolism
Risk factors
These include obesity, old age and malignant disease.
Long operations, pelvic and hip surgery, a past history of
DVT or pulmonary embolism and varicose veins increase
the risk. Other provoking factors are pregnancy and the
oral contraceptive pill.
Incidence
The incidence varies with the type of operation and the
risk factors mentioned.
Key point
• It is estimated that for every 1000 operations
there are 100 deep vein thromboses, ten
pulmonary emboli and one death.
Diagnosis
Early diagnosis is difficult and clinical diagnosis inac-
curate. Experimentally, 125 I-hbrinogen scanning is sensi-
tive in detecting developing thrombi but is of no value for
established thrombosis. It is likely this test overestimates
the incidence of clinically significant thrombi. The new
D-dimer assay is a very sensitive screening test which can
be performed at the bedside. Validation is still required
but it seems likely that, if the test is negative, DVT is not
present. Be cautious in interpreting the result as it may be
positive, for example in the presence of an inflammatory
process. Doppler ultrasound scans are valuable detecting
peripheral sites. However, isolated calf vein thromboses
are probably of no significance.
For suspected iliofemoral thrombosis a colour duplex
scan is the investigation of choice. Where this is negative,
repeating the scan in 1 week is probably preferable to
venography. Venography has been the gold standard for
diagnosis in the past but colour duplex appears to be
more accurate and is clearly less invasive.
Prophylaxis
Because of the difficulties of diagnosis, prophylaxis is the
cornerstone of management. Correct risk factors such as
obesity, or stop the taking of the contraceptive pill if clini-
cally possible. The time of maximum risk of a thrombosis
developing in surgical practice is during the operation,
when the three factors of stasis, endothelial trauma and
increased coagulability are most prevalent.
Electrical methods of stimulating muscle function and
thereby maintaining blood flow have been superseded.
Mechanical methods, such as intermittent pumping of the
calves by air insufflation of below knee stockings, are
again popular.
Subcutaneous calcium heparin (5000 units), injected 2 h
before surgery and continued postoperatively 12-hourly
until the patient is fully mobile, is a well-established
method of reducing the incidence of DVT. Calcium
heparin causes less bleeding than sodium heparin. More
recently, the low molecular fragment heparin has been
shown to be at least as effective for general, gynaecologi-
cal and orthopaedic surgery. It may reduce the risk of
perioperative bleeding, although this is still debated. A
once per day dosage regimen saves nursing time,
decreases patient discomfort and is cost effective. Some
orthopaedic surgeons favour full anticoagulation with
warfarin as prophylaxis for major joint replacement, espe-
cially for revision surgery. Shorter operating times and
earlier mobilization have contributed to the decreased
risk.
Treatment
Do not anticoagulate the patient if the thrombus can be
shown to be confined to the calf and is less than 5 cm
long. Analgesics and support stockings may well be
helpful. Take care when actively treating patients with a
dyspeptic history or with a history of cerebrovascular
accident.
Most patients require intravenous heparin; give a
loading dose of 10 000 units, followed by continuous
intravenous infusion to prolong the activated partial
thromboplastin time (APTT) by twice the control level.
Thereafter, continue anticoagulation with warfarin for at
least 3 months. Especially in hip replacement, the risk of
DVT persists for several weeks. Low molecular weight
heparin by subcutaneous injection is being used increas-
ingly for established DVTs.
Complications
Pulmonary embolism may be fatal. Multiple emboli
produce pulmonary hypertension. Diagnosis is on the
basis of a radioisotope ventilation/ perfusion lung scan.
380
COMPLICATIONS: PREVENTION AND MANAGEMENT
36
More recently spinal computerized tomography (CT) scans
have proved of greater value. If surgery is contemplated,
as for a major embolism in a specialist centre, perform pul-
monary angiography if time allows. Alternatively, stimu-
late thrombolysis using streptokinase or urokinase, or fully
anticoagulate the patient, as described for DVT.
Postphlebitic limb is more likely to follow an occlusive
iliofemoral thrombosis. Treatment is symptomatic with
support stockings and analgesics or aimed at treating the
venous ulcers, which can complicate this condition, prob-
ably secondary to dermatoliposclerosis.
Respiratory complications
Postoperative respiratory complications are the most
common, but because of the various risk factors involved
a true incidence is difficult to establish.
Risk factors
Arterial oxygen tension falls gradually with age, more
rapidly over the age of 80. Vital capacity, lung capacity,
peak expiratory flow rate and postexpiratory volume are
all reduced. Cardiovascular disease is more common with
advanced years and a combination of cardiovascular and
respiratory problems is particularly serious.
The risk of respiratory complications is increased with
obesity, excessive sedation, immobility, pre-existing lung
disease and myocardial disease, especially following
cardiothoracic, upper abdominal and vertical wounds,
all of which reduce expiratory movements.
Pathology
The commonest problem after surgery is atelectasis
(Greek a = not + telos = complete + ektasis = stretching out,
expansion). Small plugs of mucus block minor air pas-
sages and cause localized collapse. The plugs can usually
be coughed clear with the aid of physiotherapy, but if
they are not, superinfection may result. Pulmonary
embolus (see above) may also predispose to infection.
Pulmonary effusion often complicates pulmonary pathol-
ogy such as infection, infarct or metastatic disease. An
effusion may also result from a subdiaphragmatic abscess
or pancreatitis, or complicate congestive cardiac failure
and hypoalbuminaemia. Pneumothorax may complicate
ventilation, or cannulation of central veins, either for
monitoring central venous pressure or for parenteral
nutrition.
Adult respiratory distress syndrome (ARDS) is the
most serious pulmonary complication in surgical practice.
It may complicate severe sepsis, fluid overload, chest
trauma, fat emboli, burn injury and inhalation pneu-
monitis. The cause is unclear but contributing factors are:
Changes in type I and II alveolar cells, resulting in loss
of surfactant and alveolar collapse.
Impaired capillary to alveolar diffusion.
Arteriovenous shunts.
The effects of endotoxin resulting in complement
activation by the alternate pathway and disseminated
intravascular coagulation (DIC).
Consequent upon the effects of endotoxin, numerous
mediatory cytokines such as tumour necrosis factor or
interleukins are released; these contribute to pul-
monary damage.
The effects of hyperoxide radicals.
Management
Where possible, correct clinical risk factors such as obesity
and smoking habit prior to surgery. Ensure that the
patient receives adequate analgesia without excessive
sedation. Encourage regular physiotherapy administered
both by the therapist and by the nursing and medical
staff. Time physiotherapy so that the patient is free of pain
but not oversedated.
Carefully monitor the pulse, respiratory rate and tem-
perature. Administer appropriate antibiotics to patients
who are pyrexial despite conservative measures, clinically
ill, at high risk, especially if there is combined myocardial
and pulmonary disease, and all patients with features of
ARDS.
Key point
• Give supplementary oxygen by mask; if despite
that, the Pao 2 falls below 75 mmHg, consider
ventilatory support.
Figure 36.1 illustrates the procedure when a 'trigger'
necessitates considering transferring a patient to the high
dependency unit for more intensive monitoring and
treatment.
Infective complications
Risk factors
Alimentary surgery generates a higher incidence of
infection: this is often associated with endogenous
organisms. In 'clean 7 surgery, infection is usually sec-
ondary to exogenous agents. Wounds may be classified
as:
Clean, such as thyroid or hernia surgery
Potentially contaminated, as in elective gastrointestinal
surgery
381
36
COMPLICATIONS
Patient 'triggers'
(using EWI)
I
HO review
5
Resolves <}
To be reviewed by
SHO or Reg,
within 30 minutes
I
Continues to
'trigger 1
JL
Critical Care
opinion
To be reviewed by Registrar
and Consultant
^^^^^^^^^™
Fig. 36.1 Patient referral algorithm. EWI = Early
Warning Indicator.
• Contaminated, as following bowel perforation
• Dirty, when there is faecal contamination.
The incidence of infection, morbidity and mortality
increases from clean to dirty. The risk of infection is
greater in all categories if surgery is performed as an
emergency.
In 'clean' operations, infection is usually secondary
to exogenous agents such as Staphylococcus aureus.
Whenever there is a series of infections in one unit fol-
lowing clean procedures, seek a source of carriage of such
organisms. In alimentary surgery the infecting organisms
are usually endogenous. These are usually Gram-negative
aerobes. Where surgery is performed in the lower ileum
and in the large bowel, remember the importance of
anaerobic infection.
Key point
• Although the incidence of wound infection is
low after clean procedures, its consequences
may be catastrophic, as following joint
replacement or valvular heart surgery.
The risk of wound infection is increased in the presence of
obesity, in haematomas and in patients with diabetes
mellitus. Other factors are glucocorticoid therapy, immuno-
suppression, malnutrition and obstructive jaundice.
Prophylaxis
Identify the patients at risk. This includes those in whom
the incidence of infection is higher and those for whom
infection is particularly hazardous. Reduce or control risk
factors if possible. Ensure that your surgical technique is
as perfect and as meticulous as possible, with particular
reference to haemostasis, avoiding excessive use of
diathermy, leaving dead space or traumatizing tissues by
rough handling.
Select the appropriate antibiotic to give the greatest
protection and tissue penetration at the time of surgery.
Remember to take account of possible patient allergies
and the cost involved. It is sufficient to give one dose
intravenously at the time of induction. Alternatively, give
one dose intramuscularly with the premedication. Give
more than one dose only if the operation lasts longer than
4 h or if there has been contamination during gastro-
intestinal surgery. In this case you are practising
treatment rather than prophylaxis.
Remember the value of mechanical bowel preparation,
which reduces loading at the time of large bowel anasto-
mosis but does not remove pathogens from the gastro-
intestinal tract.
There is continuing controversy about the need for, and
timing of, shaving the operative area (see Chs 15, 22).
There is some evidence that shaving increases the number
of potential pathogens on the skin. There is also contro-
versy about the agent used for skin preparation,
Chlorhexidine in spirit (Hibiscrub) or aqueous povidone-
iodine (Betadine) are both acceptable. Debate continues
about the value of intracavity antibiotics or antiseptics
and these have probably been superseded by prophylac-
tic antibiotics.
In potentially contaminated surgery there is no value in
using plastic drapes; these tend to increase the number of
pathogens on the skin. The use of danger towels, separate
knives for incising skin and deeper tissues and changing
gloves after performing anastomoses are now of histori-
cal interest only
The principles of antibiotic prophylaxis are:
1. Identify patients at risk.
2. Select an appropriate antibiotic according to the type
of operation.
3. Take account of the patient's allergies and the costs
involved.
4. Administer the antibiotic, either intravenously at
induction or intramuscularly with the premedication;
ensure adequate serum and tissue levels at the time
of surgery.
382
COMPLICATIONS: PREVENTION AND MANAGEMENT
5. Repeat the administration of antibiotic in operations
lasting longer than 4 h.
E
Key point
• Antibiotics are no substitute for gentle
handling of tissues, careful haemostasis,
judicious use of diathermy and avoiding
strangling tissues with ligatures and sutures.
Treatment
Wound infection. Open the wound to allow ade-
quate drainage. Obtain pus for culture to establish the
infecting organism(s) and their antibiotic sensitivity.
Irrigate the wound for adequate drainage and debride-
ment. Formally reopen and surgically debride dirty
wounds. If clean wounds become infected, consider
cross-infections and investigate the likely sources.
Use antibiotics only if specifically indicated (for cellu-
litis or septicaemia) or if the consequences of infection
would be disastrous (see above).
If the wound infection is chronic, consider the possibil-
ity of specific organisms such as Actinomyces, a foreign
body, such as a suture in the wound, an associated fistula
as may occur in Crohn's disease/ or associated factors
such as irradiation and perineal wounds. Remember the
danger of synergistic infections and dermal gangrene.
Postoperative abscess. These are usually intraperi-
toneal but can occur deep in the wound. Localize the
abscess and attempt drainage, if necessary under ultra-
sound or computed tomography (CT) control. Monitor
resolution of the cavity radiologically if necessary.
Exclude anastomotic leakage as a cause (see below).
If the patient remains toxic or the cavity fails to resolve,
proceed to operative drainage and definitive treatment of
any underlying sepsis. If you strongly suspect an abscess,
this may involve an exploratory laparotomy, even when
the scan is inconclusive.
Septicaemia and septic shock. The septic compli-
cations mentioned above may progress to septicaemia
and septic shock in patients who are debilitated by
disease or drug therapy such as steroids or cytotoxic
chemotherapy. However, some organisms may be partic-
ularly virulent from the outset.
Remain alert after operation for all septic problems. The
danger signs are:
• Persistent, often swinging pyrexia with tachycardia
• Signs of toxicity - flushed warm skin, glazed eyes,
tachypnoea
• Falling urinary output - less than 40 ml fr 1
• Hypoxaemia.
Key point
• Treat suspected septic shock effectively to
avoid low output septic shock with its
associated high mortality (>50%).
The nature of death in such patients is multiple organ
failure, and while a patient may survive failure of a single
organ system such as the kidneys, the more organs which
fail the higher the mortality (Table 36.3).
This problem is most likely to be encountered if you
delay identifying and localizing a septic focus, and fail to
institute adequate initial treatment.
The principles of treatment are:
1 . Ensure adequate circulating blood volume using a
mixture of crystalloid and colloid fluids, aiming for a
central venous pressure of 10-15 cmH 2 in a
ventilated patient.
2. Oxygen supplementation.
3. Broad-spectrum intravenous antibiotic(s).
4. Ventilatory support if the Pao 2 is less than 75 mmHg
despite 40% oxygen by mask.
5. Cardiac support with such drugs as dopamine,
dobutamine, digitalis and catecholamines, as
indicated.
6. Attention to renal function with dialysis for
established renal failure.
7. Early recognition and treatment of any evidence of
multiple organ failure.
8. Collaborate closely with specialist colleagues in
intensive care, and where required with cardiac,
respiratory and renal physicians.
More controversial are the methods used in some centres
to ensure gastrointestinal decontamination. This involves
a combination of enteral antibiotic and antiseptic agents,
combined with a parenteral antibiotic, and this is gaining
popularity. The value of enteral glutamine and/or a-
ketoglutarate is considered vital in several intensive care
units. This is yet to be proven in a controlled trial.
However, enteral nutritional support is preferable to the
parenteral route.
Table 36.3 Multiple organ failure: rates of survival
No. of organs
1
2
3
Survival (%)
90
40-50
5-10
383
36 7
COMPLICATIONS
Anastomotic leakage
Anastomotic leakage may complicate any anastomosis,
but is seen most commonly following oesophageal and
colorectal surgery. In the latter group, leakage results in a
threefold increase in operative mortality.
Colonic anastomoses below the pelvic peritoneal
reflection are associated with an increased risk of
leakage, both clinically and radiologically detected
(Table 36.4). The clinical rate always underestimates the
true incidence of leakage, as detected by Gastrografin or
barium enema.
Predisposing factors
The general factors are similar to those which apply to
wound healing in general, such as nutritional deficiencies
(particularly protein, vitamin C and zinc), old age and
impaired local blood flow from general conditions such as
arteriosclerosis and cardiac disease.
Local factors include tension at the anastomosis and
poor surgical technique with regard to preparing the
bowel ends, handling of tissues / excessive use of
diathermy and the insertion and ligation of sutures.
Contamination of the anastomosis with liquid faeces
prejudices healing, as does an inadequate vascular supply
to one or both sides of the anastomosis. Less important
factors are the suture material, the number of layers
employed, and whether a stapling or suturing technique
is used. However, there is preliminary evidence that
tumour recurrence is lower in experimental studies when
stainless wire is used for the anastomosis and, in clinical
work, if the anastomosis is stapled.
Presentation
Gastrointestinal contents may be identified in the wound
or at a drain site. An intra-abdominal abscess or more
serious septic complication may develop. There may
be prolonged adynamic ileus, unexplained pyrexia or
Table 36,4 Rates of clinically evident and
radio logically detected leaks following colonic
anastomoses performed above and below the
pelvic peritoneal reflection
Location of anastomoses Detected leaks {%}
Clinical Radiological
Above pelvic peritoneum 1.2
Below pelvic peritoneum 16
18.3
33
tachycardia, sudden collapse postoperatively or develop-
ment of an internal fistula.
Where there is any doubt, confirmation can often be
obtained from a gently performed X-ray using a contrast
medium. In this regard, Gastrografin, which is water
soluble, is preferable to barium because leakage of barium
has much more serious consequences if present free in the
peritoneal cavity.
Management
If the patient is adversely affected by peritonitis, shock or
infection, be prepared to intervene with:
1 . Adequate resuscitation
2. Antibiotic cover
3. Operation.
The surgical procedure depends on the operative find-
ings, but the principles are:
1. Thorough peritoneal lavage with cefuroxime and
warmed saline (1.5 g l -1 ).
2. Identification of the leak and any associated
pathology, such as Crohn's disease.
3. Resection of the affected area. Never try to insert a
few extra sutures, as the tissues are very friable and
you may cause more damage rather than achieve
repair.
4. Be prepared to establish a proximal stoma and a
distal mucous fistula or carry out a Hartmann's type
procedure of closing the distal rectal stump.
5. Very occasionally, if contamination is slight,
conditions are satisfactory and you are expert, you
may elect to excise the margins and reform the
anastomosis.
6. As a rule, after restoring the patient's health and
nutritional status over a minimum of 6-12 weeks,
you may reanastomose the bowel ends.
In the presence of a fistula, management depends on the
state of the patient and the volume draining. When the
volume is small (i.e. less than 500 ml per 24 h) and the
patient is well, initially treat the patient conservatively:
1. Restrict oral intake.
2. Give intravenous fluids.
3. Correct fluid, protein, electrolyte, acid-base and
vitamin deficiencies (see Chs 9, 10).
4. Treat associated sepsis.
5. Institute nutritional support.
6. Consider the somatostatin analogue octreotide to
reduce gastrointestinal secretion and motility. If such
treatment fails or the output is high (>500 ml day" 1 )
or there is associated sepsis, you must intervene
surgically.
384
COMPLICATIONS: PREVENTION AND MANAGEMENT
36
Problems with the wound
Failure of wound healing may result (in descending order
of importance) in wound dehiscence, incisional hernia or
superficial wound disruption. Wound dehiscence should
now be less than 0.1%. Incisional hernia is more common
but should occur in less than 10% of abdominal wounds.
Risk factors
General risk factors include respiratory disease, smoking,
obesity obstructive jaundice (especially secondary to
malignant disease), nutritional deficiencies of protein,
zinc and vitamin C, malignant disease, steroid therapy,
and following emergency procedures.
Local risk factors include wound infections, impaired
blood supply, foreign body in the wound and previous
irradiation to the area. Clean incised wounds heal better
than ragged traumatic wounds. The site of wound is
important: the anterior tibial area is notorious for wound
breakdown, as are flap wounds with inappropriate
length-to- width ratio. Poor surgical technique is another
important factor.
Prevention
As in all complications, the cornerstone of success is to
recognize risk factors, correct those that can be corrected
and use an appropriate surgical technique for all wounds.
For closing the abdominal wall, the best results are
obtained by suture with a non-absorbable material, such
as nylon, or an absorbable suture with prolonged tensile
strength, such as polydioxanone. The Jenkins technique of
mass closure is now well-established: take 1 cm bites,
1 cm apart, avoiding too much tension in the closed
wound.
Key point
• To avoid wound complications, ensure that
your surgical technique is perfect, and choose
your materials appropriately.
Management of superficial disruption
• Evacuate haematoma and /or pus.
• Excise and remove slough.
• Remove any foreign body.
• Irrigate with, for example, hydrogen peroxide and
povidone-iodine.
• Pack gently to avoid too rapid healing over of the skin,
but avoid trauma to granulation tissue.
• Carefully monitor healing by secondary intention.
• Use newer materials such as Kaltostat or Sorbsan,
which are well tolerated, highly absorbent alginates for
wounds containing slough.
Management of wound dehiscence
The mortality reported following abdominal wound
rupture varies from 24% to 46%.
• Recognize the problem early.
• Do not overlook premonitory serous discharge from
the wound, a prolonged ileus, or low grade pyrexia.
• Resuscitate the patient.
• Re-explore the abdomen and perform adequate peri-
toneal lavage.
• Proceed to resuture the abdomen under general anaes-
thetic, using an adequate length of non-absorbable
suture without tension.
• Use 1 cm bites about 1 cm apart.
• Avoid pulling the suture tightly in the tissues.
• It may be helpful to decompress the small bowel in
retrograde fashion to reduce intra-abdominal tension.
Recurrence is uncommon but incisional herniation com-
plicates approximately 25% of cases.
Management of incisional hernia
The indications for surgical intervention are obstruction,
pain, or increasing size that makes control difficult. First
spend time reducing such risk factors as obesity, smoking,
constipation and prostatism. Assess the overall prognosis.
Not all patients require or want surgical repair. Repair is
unrewarding in the presence of unresected neoplastic
disease. An abdominal support will control symptoms in
most elderly and high risk patients.
Historically, a number of options are available as
regards surgical technique, including Mayo or Keel
repairs. However, except where the hernia is very small,
a mesh repair is now the treatment of choice. Operative
mortality should be less than 1 % and the recurrence rate
5-10%. If a patient is morbidly obese at the time of repair
a satisfactory result is less likely The main problem with
mesh repair is if infection supervenes. Under those cir-
cumstances it is most unusual that the repair will heal
because of the presence of a foreign body. You will need
to remove the mesh, allow the sepsis to settle completely,
then start afresh. Meshes impregnated with antibiotics for
high risk recurrent cases are under trial.
Hypertrophic and keloid scarring
Hypertrophic scars are limited to the wound area and do
not advance after 6 months. Keloid (Greek kele — claw +
eidos = like) scars are more extensive and continue to
385
36
COMPLICATIONS
expand beyond 6 months, but fortunately are much less
common. Predisposing factors are pigmented skin, burn
trauma, wounds on posterior aspects, younger age
groups, and a past history of keloid scarring.
There is excessive production and contraction of fibrous
tissue. The synthesis of collagen is increased but the scar
contains embryonic or fetal collagen. Only in hypertrophic
scars is there an increased lysis of collagen. The main com-
plication is joint deformity but the cosmetic problems can
be considerable in exposed sites and with younger patients.
Successful treatment is difficult, and should not be con-
templated until 6 months from injury. There is no treat-
ment for hypertrophic scars; do not attempt to treat keloid
scars until they are mature. Re-excision with and without
pressure or plastic procedures are as disappointing as
radiotherapy Greater success has been claimed for injec-
tion of steroids into the wound. The mode of action
appears to be increased collagen lysis, with depression of
the proliferation of fibroblasts. Injection of triamcinolone
can be repeated at intervals of 1 or 2 weeks, depending on
the result achieved.
Prevention
r
Key points
• Recognize patients at risk of bleeding and
reverse the risk factors before operation.
• Control infection.
• Ensure your surgical technique is meticulous.
In patients on long-term warfarin it is relatively straight-
forward to convert the anticoagulation to intravenous
heparin, which can be reversed more rapidly than war-
farin by the injection of protamine.
Cooperate with a haematologist (see Ch. 8) in managing
patients with coagulation disorders. Infuse specific factors
as required. Timing is vital; for example, if fresh platelets
are required for patients undergoing splenectomy, they
must be given after the spleen has been removed. Give
vitamin K by the intravenous route to reverse the prob-
lems associated with the obstructive element of jaundice.
Haemorrhage
Incidence
The incidence and severity of haemorrhagic complica-
tions are not easy to quantify. It is uncommonly necessary
to re-explore a wound, evacuate haematoma and secure
haemostasis. Wound haematoma and local bruising are
sufficiently common to make it difficult to differentiate a
complication from a normal sequel of surgery.
Where bleeding complicates intra-abdominal surgery
warning signs are haemodynamic instability with rising
pulse and falling blood pressure, reduction in hourly
urine volume to less than 40 ml h" 1 , and excessive volume
draining from the abdominal drain.
Predisposing factors are obesity, long-term steroid
therapy, and jaundice. Recent transfusions of stored
blood, coagulation diseases, platelet deficiencies and
anticoagulant therapy may result in haemorrhage, and in
old age there is increased capillary fragility. Severe sepsis
may result in disseminated intravascular coagulation.
Pathology
It is conventional to consider primary haemorrhage as
that occurring within 24 h of surgery This is usually a
technical problem of haemostasis. The operative area
appears dry but with restoration of normal blood press-
ure or continuous infusion of intravenous fluids a vessel
may dilate and bleed. In secondary haemorrhage, bleed-
ing usually occurs 5-10 days after operation. It is due to
local infection, sloughing of a clot or erosion of a ligature.
Management
The need for intervention is dictated by the patient's
symptoms and vital signs. Where haemorrhage is overt it
is usually easier to decide whether exploration of the
wound and cavity is indicated or not. When bleeding is
internal you cannot rely on the effectiveness of an intra-
cavity drain.
• Check a clotting screen to assess any established prob-
lems and to identify any new ones.
• Correct any deficit appropriately with vitamin K by
injection for problems with the clotting mechanism,
expressed as the international normalized ratio (INR).
Use specific factors for deficiencies, fresh frozen
plasma, and fresh platelets as indicated by the results
of the coagulation study.
• Do not undertake surgical exploration until you have
corrected any deficit, at least in part.
• It is unusual to identify a specific bleeding point at
exploration.
The principles of surgery are to evacuate the blood and
clot, identify any bleeding point or points, and control
them appropriately If a troublesome ooze persists, try the
effect of a haemostatic agent such as Spongistan, or a col-
lagen derivative. If you still cannot control the bleeding,
pack the raw surface for 24^18 h. Consider leaving the
superficial wound open. When you suspect a deeper
source, and fear recurrent bleeding, as following a pan-
creatic operation, consider creating a laparostomy; leave
the main wound open, packed with sterile packs. This
facilitates re-exploration.
386
COMPLICATIONS: PREVENTION AND MANAGEMENT
36
Summary
• Do you realize that the combination of cor
pulmonale and ischaemic heart disease, or
low output septic shock, carry up to 50%
mortality?
• Do you appreciate the importance of
correcting comorbidity factors before
operation whenever possible?
• Are you aware that there are many
complications that are common to all
types of operation?
• Will you study the special risks you will
encounter in each form of surgery?
Further reading
Cuschieri A, Giles GR, Moossa AR 1988 Essential surgical
practice. Wright Bristol
Pollock AV 1991 Postoperative complications in surgery.
Black well Scientific, Oxford
Smith JAR (ed.) 1984 Complications of surgery in general.
Bailliere Tindall, London
Tayfor I, Karran SJ (eds) 1996 Surgical principles. Edward
Arnold, London
387
Intensive care
J. Jones, R. C Leonard
Objectives
To identify the signs of impending critical
illness.
To understand the early and ICU
management of critical illness.
To appreciate the limitations of intensive
care.
Decision making
1 . Advice on critically ill patients must be provided at
a senior level. Never take it upon yourself to manage the
sickest patients in the hospital without asking your con-
sultant for support. Events proceed much more quickly in
ICU than elsewhere, and what would be an acceptable
delay on the wards is often not tolerated by ICU patients
or staff.
HYTRODUg^
Although it has never been proved, it is likely that very
sick patients can be managed better and more efficiently
in a separate area specially equipped for their needs. In
the UK, the Department of Health has recommended that
intensive care units (ICUs) should represent 1-2% of
acute hospital beds. This proportion is lower than in
almost all other Western countries, and is now manifestly
inadequate.
Organization
1. Critical care is labour intensive, and properly trained
staff represent by far its most valuable resource. There
should be one nurse for each ventilated patient and a
senior nurse whose sole responsibility is to manage the
unit.
2. There should always be at least one doctor capable
of managing the airway on duty within the ICU and free
from other commitments. A consultant must be immedi-
ately available. Although in the past most intensive care
consultants in the UK have been anaesthetists, care of the
critically ill requires close cooperation across many disci-
plines. The recent emergence of intensive care as a spe-
cialty in the UK has resulted in the creation of a small
number of specialists capable of directing this complex
multidisciplinary process. There is now evidence that
intensive care units controlled by intensivists have better
outcomes and shorter patient stays than those that are not
(Carson et al 1996, Ghorra et al 1999, Baldock et al 2001).
Key points
• Offer intensive care only to those who need it
and will benefit from it.
• Respond quickly to requests for advice or
assistance from the ICU staff.
2. It is often said that it is not reasonable to refuse
admission to ICU simply on the grounds of advanced age,
and that old people have been shown to respond to inten-
sive care just as well as younger ones with similar dis-
orders. While this is true, death cannot be postponed
indefinitely, and the humane and reasonable use of inten-
sive care over the age of 80 requires particular care in
patient selection. Regardless of age, when the appropri-
ateness of ICU admission is in question, an assessing
intensivist needs the following information:
a. Current diagnosis and its prognosis
b. Comorbidities
c. Functional status; often a decisive factor - exercise
tolerance, mobility, ability to do housework, shop, and
venture outside the home.
3. Clearly judgements regarding the possible with-
holding of life-sustaining treatment can be difficult. They
should be made at a senior level, whenever possible
involving the patient (see Chs 14, 47). If the patient is not
competent, the role of the next of kin is to represent
the likely wishes of the patient regarding treatment.
However, it is inhumane and morally irresponsible to
leave such decisions to the relatives alone. The current
fashion of seeking written agreement from the next of kin
388
"^
INTENSIVE CARE
37
before making an order not to attempt resuscitation often
leaves families feeling that they must bear ultimate
responsibility for their relative's death. Conduct dis-
cussions in terms of 'working together to decide what the
patient would want us to do', not of 'asking consent to
withdraw or withhold treatment'. Dealing explicitly with
death can be painful and difficult but should not be
avoided until it is too late; patients and their families are
sometimes surprisingly grateful for the chance to discuss
these issues openly.
4. Intensivists often receive requests for manifestly
inappropriate admission to ICU, justified by the words
The family wants everything done'. Such requests repre-
sent failures of communication during the decision-
making process outlined above. The intensivist should
not be asked to take on the responsibility for communi-
cation, which lies with the referring specialist.
5. It has been shown that some patients are admitted to
ICU too late in the course of their disease (McQuillan
et al 1998). Earlier treatment might improve outcome and
perhaps even avoid ICU admission altogether. For this to
succeed, it is necessary to detect deterioration early and
then provide staff capable of intervening effectively. The
concept of a medical emergency team, called in response
to defined physiological criteria, has been suggested as a
solution. While this is theoretically attractive, outcome
benefits have yet to be demonstrated (Bristow et al 2000).
It may be impossible to detect deterioration soon enough
to affect the course of the disease.
6. Successful management of the critically ill patient
requires that two processes occur simultaneously:
a. Resuscitation from the pathophysiological
derangement
b. Diagnosis and specific treatment of the underlying
disease.
Key point
Critically ill patients need resuscitation,
diagnosis and specific treatment.
CORRECTING THE PHYSIOLOGY OF
CRITICAL ILLNESS
We shall consider the vital systems serially (in succes-
sion); in reality they must be dealt with simultaneously -
in parallel. Safe threshold limits for physiological values
are given in order to provide practical guidance but there
are some for whom these limits are too permissive or too
stringent. If you ignore these limits without seeking
senior advice you endanger the patient and will be called
to account.
Cardiovascular pathophysiology
The function of the circulation is to transport oxygen and
nutrients to the tissues and to remove metabolic waste
products. There must be:
• Enough oxygen in the blood
• Enough blood flowing (cardiac output)
• Enough blood pressure to let tissues regulate their own
perfusion.
1. The oxygen content of blood is determined by the con-
centration and oxygen saturation of haemoglobin.
2. Blood pressure is determined by the equation
BP = COxTPR
where BP = blood pressure, CO = cardiac output, and TPR
= total peripheral resistance. Thus hypotension can be
due either to low cardiac output or to inappropriate
vasodilation. Treatment usually requires correction of the
abnormal variable.
3. Cardiac output is determined by:
a. Rate. Too high a heart rate prevents adequate filling
of the ventricle and reduces preload and cardiac output.
Bradycardia reduces cardiac output as ejection simply
does not happen often enough.
b. Rhythm. Loss of atrial contraction in junctional
rhythms or atrial fibrillation also reduces preload and
hence cardiac output by up to 30%.
c. Preload. The law of the heart described by Henry
Starling in 1915, states that the force of contraction of a
cardiac muscle fibre is proportional to its initial length.
The fibre length is determined by the ventricular volume.
However, volumes are difficult to measure clinically and
the simplest substitute is the central venous pressure
(CVP). The relationship between pressure and volume is
not linear and is described by the ventricular compliance,
which varies both between individuals and within each
individual over time. For this reason, and because of the
shape of the ventricular compliance curve (Fig. 37.1), it is
usually not possible to determine the true preload or
volume status from a single measurement of the CVP.
Key point
• To check the volume status, observe the
response of the CVP to a fluid challenge.
Give 250 ml colloid over 10 min. The response indicates
the volume status (Gomersall & Oh 1997):
389
37
COMPLICATIONS
to
Q.
(A
■
C
i-
.5
(J
C
c
3
Low preload High preload
Ventricular end-diastolic volume
Fig. 37.1 The ventricular end-diastolic pressure-volume
curve shows how, for a given pressure, the preload may
be low or high because of the shape of the curve and
the fact that compliance can vary between individuals
and within individuals over time.
- if the CVP rises by more than 7 mmHg the patient is
hypervolaemic
- if the CVP settles to within 3 mmHg of the original
value, the patient is euvolaemic
- if the CVP rises by less than 3 mmHg the patient is
hypovolaemic.
Serial fluid challenges may be given until the response
suggests volume replacement is adequate.
d. Contractility is defined as the intrinsic ability of the
myocardium to contract, independent of loading condi-
tions. It is impossible to measure directly even under lab-
oratory conditions, and must be inferred clinically from
the CVP, blood pressure and assessments or measure-
ments of the cardiac output. If preload is adequate, and
blood pressure remains low, with evidence of a low
cardiac output, contractility is usually impaired.
e. Afterload. Cardiac output is inversely related to the
afterload, which may be defined either as the aortic input
impedance or as the systolic ventricular wall tension.
Afterload is reduced by:
- vasodilation (including rewarming of hypothermic
patients)
- positive intrathoracic pressure
- intra-aortic balloon counterpulsation.
Manipulation of afterload in cardiogenic shock is
complex and difficult, and is outside the scope of this
introduction.
It is not often necessary to measure cardiac output in
clinical situations. It is debated, but with very unreliable
evidence, whether there is an association between the use
of pulmonary artery catheters to measure cardiac output
and an apparent increase in mortality (Connors et al
1996). Less invasive methods of monitoring cardiac
output are gaining in popularity.
4. Shock may be defined as inadequate tissue perfusion.
It can be categorized into four types:
a. Hypovolaemic shock is due to a reduction in circulat-
ing volume following haemorrhage or dehydration.
Venous return to the heart and hence ventricular preload
are reduced, and the cardiac output and blood pressure
fall. Reflex tachycardia and vasoconstriction partially
compensate for the hypotension.
b. Cardiogenic shock results from primary myocardial
dysfunction, reducing contractility and cardiac output.
Causes include myocardial infarction and myocarditis.
Once again, blood pressure is low, and reflex tachycardia
and vasoconstriction occur in an attempt to compensate,
but CVP is raised as the heart fails to eject the venous
return adequately.
c. Obstructive shock occurs when an adequately filled
heart is unable to eject its contents because of pericardial
tamponade, tension pneumothorax or massive pul-
monary embolism. CVP is again high because of the
failure to eject, while cardiac output and blood pressure
are low and the usual compensatory reflexes ensue.
d. Distributive shock refers to a condition of patho-
logical vasodilation and capillary leak, which result in
hypotension with a normal or high cardiac output. The
condition is seen in sepsis, burns, pancreatitis and ana-
phylaxis. As the disease progresses, the capillary leak
produces hypovolaemia. Multiple organ failure is char-
acteristic of septic shock, and causes acute lung injury,
renal failure and coagulopathy. Although there is a high
cardiac output, it appears that there is a defect of tissue
oxygen utilization. It is presently uncertain whether this
is due to derangement of the microcirculation or of mito-
chondrial function.
Anaphylaxis (Greek ana = without + phylaxis - protec-
tion) usually follows immediately after the administra-
tion of drugs, colloids or contrast media. As in septic
shock, there is profound vasodilation and increased ca-
pillary permeability Urticarial rashes and bronchospasm
are also common.
Inadequate tissue perfusion produces the signs of
shock listed in Table 37.1. As can be seen, the disorder
involves several systems.
5. Hypotension.
Table 37,1 Signs of inadequate tissue perfusion
Hypotension (BP < 90 mmHg)
Tachypnoea
Oliguria
Agitation, confusion or coma
Slow capillary refill (not in early sepsis)
390
^9*i
INTENSIVE CARE
37
Ml
Key points
Patients with the signs of shock are critically ill
and are liable to rapid decompensation.
They need urgent resuscitation.
While there may be patients for whom a slightly lower BP
is acceptable (for instance the rule does not necessarily
apply under anaesthesia), if you are inexperienced, do not
take such a decision alone. Conversely if a patient has a
systolic BP of 100 mmHg, but shows all the other signs of
inadequate tissue perfusion, treat them with the same
urgency as a shocked hypotensive patient.
The early management of hypotension follows from
the physiological principles above, and is described in
Table 37.2. ICU admission may become necessary at any
stage in this process, but is usually inevitable if vaso-
active drugs are required.
The most important point to realize is that, contrary to
the myths instilled into all trainees at medical school, it is
generally far safer to give fluids than to withhold them.
It is not clear what the appropriate goals of resuscitation
are. The past fashion for targeting supranormal values
of oxygen delivery (the product of oxygen content and
cardiac output) is no longer sustainable. In the absence of
convincing evidence, aim for these endpoints:
• Mean BP > 70 mmHg
• Resolving tachycardia
• Improved peripheral perfusion
• Urine output improved above at least 0.5 and prefer-
ably 1 ml kg 1 h 1
• Resolving acidosis and falling lactate.
Table 37.2 Management of hypotension
Key points
A non-pregnant adult with systolic blood
pressure below 90 mmHg has dangerous
hypotension and requires immediate
treatment.
It is generally far safer to give fluids than to
withhold them.
Respiratory pathophysiology
The respiratory system transports oxygen to the blood
and removes carbon dioxide from it. Success requires an
adequate volume of gas to ventilate the alveoli and close
matching of the degree of ventilation and perfusion of
each lung unit. Failure results in hypoxaemia / hypercar-
bia (raised blood carbon dioxide) or both.
Check for airway, breathing and circulation
Check the BP yourself
Automatic BP machines measure the mean
arterial pressure; the systolic and diastolic
pressures they display are calculated and may
therefore be inaccurate
Give high flow oxygen
Check for signs of shock
Establish large-bore venous access (14 gauge or
16 gauge) and draw blood for...
Investigations: FBP r coagulation studies, U&E r
amylase, cardiac enzymes, arterial blood gases,
chest X-ray, ECG
Examine for signs of pulmonary oedema. If a
hypotensive patient has pulmonary oedema, he
or she is desperatefy ill and needs expert
assistance from the ICU immediately. If there is
no pulmonary oedema it is safe to give fluid
Give 500 ml of any fluid except 5% dextrose,
and repeat as necessary
Take a history, examine the patient, MAKE A
DIAGNOSIS AND GIVE SPECIFIC TREATMENT
If there is no response after between 1000 and
2000 ml fluid, insert a central venous catheter
and titrate filling using serial fluid challenges as
described above
If hypotension persists despite adequate filling,
give vasoactive drugs: i not ropes (adrenaline
(epinephrine)) if cardiac output is low or
uncertain; vasoconstrictors (noradrenaline
(norepinephrine)) if cardiac output is high. It is
sometimes necessary to measure cardiac output
directly in order to make this distinction
Ventilation-perfusion (VIQ) matching
Consider the idealized alveolar-capillary unit rep-
resented in Fig. 37.2. If perfusion and ventilation are
either perfectly matched or completely mismatched, then
there are three possible situations:
1. Perfect matching of ventilation to perfusion (V/Q = 1).
2. Normal ventilation but no perfusion (V/Q = ~>), as
shown in Fig. 37.3, analogous to that existing in the
anatomical dead space, which refers to that part of the
tidal volume which does not reach a surface where gas
exchange can occur.
3. Normal perfusion but no ventilation (V/Q = 0), as
shown in Fig. 37.4, resembles what happens to the
venous blood which is shunted anatomically past the
lungs without participating in gas exchange because it
passes through the thebesian or bronchial veins (in
normal subjects) or a right-to-left intracardiac shunt (in
patients with cyanotic congenital heart disease). These
391
37 \
COMPLICATIONS
Fig. 37.2 Idealized alveolar-capillary unit showing
ventilation of the alveolus and perfusion of the capillary.
Fig. 37.4 Normal perfusion but no ventilation (V/Q = 0),
referred to as shunt.
situations are therefore referred to as representing the
physiological dead space and the physiological shunt.
Dead space ventilation decreases the proportion of each
breath that participates in gas exchange, and hence alve-
olar ventilation falls. Unless the respiratory rate rises to
compensate, hypercarbia will ensue.
The consequence of blood being shunted through the
diseased, unventilated lung tissue without engaging in
gas exchange is that unoxygenated venous blood is mixed
into the blood that has been oxygenated; hence, arterial
oxygen content falls.
Fig. 37.3 Normal ventilation but no perfusion (V/Q = °°),
referred to as dead space ventilation.
In reality, there exists a spectrum of V/Q relationships
from to oo. The vast majority of lung units of healthy
subjects are tightly clustered around the ideal situation,
with a few outliers, as shown in Fig. 37.5. However, when
the lungs are diseased there is an increase in the scatter of
the V/Q ratios, which causes an increase in physiological
shunting and dead space ventilation.
t/i
en
E
3
1
V/Q relationship
«
Fig. 37.5 Scatter of V/Q ratios in a healthy subject
(solid line) and in a patient with respiratory disease
(dotted line). Note the increase in physiological shunt
and dead space.
392
INTENSIVE CARE
37
Hypercarbia
Caused by reduced alveolar minute ventilation, hyper-
carbia results from:
1 . Reduced respiratory rate (hypoventilation)
2. Increased physiological dead space ventilation.
Both of these can be corrected or compensated by increas-
ing the respiratory rate.
Hypoxaemia
Hypoxaemia is caused by:
1. Hypoventilation. When the rate at which fresh in-
spiratory gas is presented to the alveoli falls, but oxygen
consumption remains the same, the partial pressure of
oxygen within the alveoli must also fall. As a result the
oxygen tension within the pulmonary capillary and hence
the systemic arteries (Pao 2 ) is reduced. Postoperative
patients may hypoventilate because of pain from upper
abdominal incisions, or because of opioid analgesia.
Clearly, the hypoxaemia of hypoventilation can be cor-
rected by increasing the respiratory rate, either pharma-
cologically or mechanically, but also more simply by
increasing the inspired oxygen fraction (Fio 2 ).
2. Shunting. True anatomical shunting cannot be cor-
rected by an increased Fio 2 , because by definition no gas
exchange occurs. Postoperative patients may develop a
shunt because of basal atelectasis (Greek a - not + telos =
end + ectasis - expansion; hence, collapse) or chest infec-
tion. However, relative physiological shunting caused by
imperfect V/Q matching can be partially corrected by
increasing the Fio 2 . Techniques available to reduce shunt
involve raising the mean airway pressure in order to
recruit collapsed lung units.
Key point
• Hypoxaemia is a far more dangerous and
rapidly lethal state than hypercarbia.
Hypoxaemia may be treated by oxygen therapy.
Oxygen therapy. It is incorrect to withhold oxygen
in the presence of chronic obstructive pulmonary disease
(COPD) for fear of inducing hypercarbic narcosis. The
false reasoning for withholding oxygen is that, although
in healthy humans the normal source of ventilatory drive
is the carbon dioxide response, patients with COPD have
a blunted response to hypercarbia and are dependent on
hypoxaemic ventilatory drive. Treatment with oxygen is
then assumed to remove this stimulus to breathe and thus
to cause hypoventilation, hypercarbia and coma. It is true
that some patients with COPD do experience an increase
in arterial carbon dioxide tension when hypoxaemia is
treated with oxygen, but it is irresponsible to treat this
response with a return to hypoxaemia. The increase in
arterial carbon dioxide tension (PaC0 2 ) rarely causes prob-
lems as long as oxygen therapy is controlled to ensure
safe but not excessive oxygen saturations (say 90-92%). If
hypercarbia does occur, and is causing problems, do not
add hypoxaemia to the patient's difficulties, but instead
refer urgently for ventilation.
Oxygen therapy is always prescribed in the early post-
operative period to treat hypoxaemia from the causes
mentioned earlier. It is known that patients continue to
experience episodic nocturnal hypoxaemia for at least
three days after surgery. This coincides with the period of
highest risk for perioperative myocardial infarction, and
anaesthetists commonly prescribe oxygen for 3 days fol-
lowing operation in patients who are at particular risk of
this dangerous complication. Do not countermand these
orders or you will be putting your patient at risk.
Oxygen can be given by the following devices:
1. Nasal cannulae deliver 2-4 1 min" 1 2 ; Hudson
masks deliver up to 15 1 min" 1 2 . Although they deliver
a known flow, the Fio 2 is determined by the amount of air
entrained by the patient during inspiration. This in turn
is determined by the peak inspiratory flow rate, which of
course varies.
2. Venturi masks (G. B. Venturi, 1746-1822, was an Italian
physicist) deliver 24-60% 2 . They use Bernoulli's principle
(as the velocity of a moving fluid increases, the pressure
within the fluid decreases) to deliver a high enough flow of
known Fio 2 to exceed the patient's peak inspiratory flow
rate, thus avoiding entrainment of further air.
3. Continuous positive airway pressure (CPAP) rep-
resents the next level of respiratory support from oxygen
supplementation. A tight-fitting mask connected to either
a large reservoir or high gas flow permits an Fio 2 of up to
1.0, while at the same time a positive pressure is applied
continuously to the patient's upper airway. This positive
pressure recruits alveoli which are collapsed due to lung
disease, and results in:
a. Reduced shunt and therefore increased Pa0 2
b. Increased lung volume and therefore (usually)
improved pulmonary compliance and reduced work of
breathing. CPAP usually has little effect on Paco 2 , despite
the reduced work of breathing.
4. Mechanical ventilation (Latin ventus = wind) may be
applied invasively (via a tracheal or tracheostomy tube)
or non-invasively via a tight-fitting face mask. The latter
technique is only suitable for conscious patients with
adequate ventilatory drive who require a modest reduc-
tion in their work of breathing and shunt. The indications
for mechanical ventilation are:
393
37 1
COMPLICATIONS
a. Respiratory failure refractory to less invasive
treatments
b. Elective postoperative ventilation
c. Physiological control (as for instance in raised
intracranial pressure).
The decision to ventilate a patient with respiratory
failure is complex, and takes into account the following
factors:
• Respiratory distress
• Respiratory drive
• Level of consciousness
• Natural history of underlying disease
• Arterial blood gas results.
Elective postoperative ventilation is often used
in anticipation of respiratory failure in the following
situations:
• Major surgery (e.g. cardiac surgery, thoracoabdominal
aneurysm repair)
• Hypothermia
• Massive transfusion
• Haemodynamic instability
• Staged procedure (e.g. following penetrating abdomi-
nal trauma or faecal peritonitis).
Mechanical ventilation carries a number of complications.
Do not seek to embark upon it without proper indica-
tions. The complications include:
• Cardiovascular compromise
• Fluid retention
• Pneumothorax
• Ventilator-associated lung injury
• Ventilator- associated pneumonia
• Accidental disconnection
• Complications relating to the artificial airway (e.g.
tracheal stenosis).
The various modes of ventilation are confusing, and
classifications of them are unhelpful. Essentially, other
than the basic goal of delivering tidal volumes of
respiratory gas to the lungs a certain number of times a
minute, the different modes are aimed at one of the
following:
• Facilitating the patient's spontaneous respiratory
efforts
• Improving oxygenation in refractorily hypoxaemic
patients
• Limiting dangerously high airway pressures
Respiratory distress
This is one of the earliest indicators of impending critical
illness, as well as the major determining factor of the need
for mechanical ventilation. The signs of respiratory
distress are:
1. Tachypnoea (Greek tacky s = swift + pnoia =
breathing)
2. Use of accessory muscles of respiration - the most
obvious being the sternocleidomastoid muscles,
which contract during inspiration
3. Difficulty speaking
4. Pulse oximeter (Spo 2 = oxygen saturation from pulse
oximeter) reading < 90%
5. Agitation, confusion or coma.
Key points
• Respiratory rate > 30 or < 8 f inability to speak
half a sentence, agitation, coma, Spo 2 < 90%,
indicate potentially serious illness.
• Provide immediate treatment.
Unless a patient with these signs improves rapidly, he or
she may require early intubation and ventilation. In the
setting of respiratory distress, agitation or coma are par-
ticularly worrying, as they make it very difficult to
manage the patient without securing the airway.
1. Spo 2 < 90% requires immediate correction, as further
desaturation is likely to be rapid.
2. A satisfactory Spo 2 reading does not rule out severe
respiratory problems. Oxygen therapy can maintain a
normal saturation until shortly before respiratory arrest
occurs.
Key point
• Monitor the respiratory rate: it is a crucial
indicator in a potentially unstable patient.
Renal dysfunction
Renal failure is a frequent problem in surgical wards and
in ICU. By far the commonest cause is acute tubular
necrosis. The cells lining the renal tubules are metaboli-
cally very active and have a high oxygen requirement; if
they are deprived of it, they swell, die and are shed into
the lumen. The same effects result when toxic substances
are excreted by the kidneys, such as gentamicin, ampho-
tericin B and cisplatin. Fortunately, the cells can regen-
erate. Inadequate renal perfusion is usually due to a
combination of hypovolaemia, hypotension, sepsis,
nephrotoxic drugs and pre-existing renal disease.
394
INTENSIVE CARE
37
In the case of sepsis, renal failure may occur as part of
the syndrome of multiple organ dysfunction, when it
carries a grim prognosis. However, if the patient survives
the acute illness, renal function usually recovers.
Key point
• Monitor urine output hourly; if it falls below
0.5 ml kg 1 rr\ correct it without delay.
Early correction of underlying renal hypoperfusion may
prevent the development of acute tubular necrosis.
Therefore:
1 . Correct hypovolemia, if necessary using CVP
guidance as described above.
2. Correct hypotension and low cardiac output, using
vasopressors or inotropes.
In previously hypertensive patients it may be necessary to
raise the blood pressure to levels close to their normal
pressure (which may be higher than the usual target mean
arterial pressure in ICU of around 70 mmHg). Only then
can the kidneys autoregulate their blood flow, allowing
renal perfusion to occur.
There is no evidence of benefit from other strategies,
including low dose 'renal' dopamine (Bellomo et al 2000).
Furosemide (frusemide) given to promote a diuresis is
common; at least it has the theoretical benefit of reducing
renal oxygen consumption and protecting the struggling
kidney against ischaemia. However, it is essential to
correct hypovolemia first.
Key point
• Do not treat oliguria with excessive early doses
of furosemide (frusemide); hypovolaemia must
be corrected first.
Other causes of oliguria in a surgical patient are
urinary obstruction, of which the commonest cause by
far is a blocked catheter, and sodium and water retention
due to the neuroendocrine stress response to surgical
trauma.
If oliguria persists despite correct treatment, it is likely
that established renal failure will develop. A high urinary
sodium (> 20 mmol I" 1 ) or a low urinary osmolality
(280-320 mOsm I" 1 ) in the absence of recent diuretic
treatment suggest renal failure. Seek the advice of an
intensivist or nephrologist. Meanwhile:
1 . Maintain euvolaemia, which usually involves fluid
restriction to 20 ml Ir 1 plus the previous hour's
output. Be particularly careful to avoid fluid
overload in patients who are not ventilated.
2. Monitor closely for hyperkalaemia and metabolic
acidosis.
3. Measure serum creatinine and urea twice daily.
Renal replacement therapy in the form of haemofiltration
or haemodialysis is indicated for hyperkalaemia, acidosis,
fluid overload or an inexorably rising creatinine. Once
dialysis is inevitable there is nothing to be gained from
procrastination; arrange for it without delay.
Acute neurological problems
You will encounter many patients with an acutely
depressed conscious level resulting from trauma, drugs,
acute intracranial event (such as infarction or haemor-
rhage) and encephalopathy of critical illness.
Key points
• Never forget to check the blood sugar level.
• Glasgow coma score (GCS) < 8 or failure to
localize to pain are indications for intubation,
ventilation, investigation and specific
treatment.
You should only ignore this recommendation for intuba-
tion if it has been decided that the patient should not have
active management under any circumstances, following
an intracranial disaster. If a CT scan shows an unrecover-
able situation, then treatment can be withdrawn at that
point.
Nutrition
1. Nutritional support is needed when the patient is
unlikely to resume normal oral intake within 7-10 days of
it ceasing (Klein et al 1997). If nutritional support is
inevitable, start it as soon as the patient is stabilized (see
Ch. 10). Discuss the timing of commencing feeding with
the intensivists.
2. Enteral feeding is cheaper, easier and therefore
preferable. Evidence for a protective effect on the intesti-
nal mucosa is weak, and complications of enteral feeding
are underreported (Lipman 1998). It has been definitely
indicted as an independent risk factor for ventilator-
associated pneumonia (Drakulovic et al 1999). Thus it is
reasonable to consider parenteral feeding in patients
with doubtful ability to tolerate enteral feeding within
395
37 y
COMPLICATIONS
7 days (Woodcock et al 2001). Meanwhile, make strenu-
ous efforts to establish enteral feeding.
3. When nasogastric feeding is not tolerated despite
giving prokinetic agents, try passing a nasojejunal tube.
This route is now commonly used in patients with pan-
creatitis. Traditionally, such patients were fed parenter-
ally, but jejunal feeding is now known to be safe and
perhaps associated with better outcomes (Pupelis et al
2001).
4. The optimal content of feeding solutions is uncer-
tain. Carbohydrates, essential lipids, protein, vitamins
and trace elements are needed, and it is clear that there
is an upper limit to the amount of both energy and
protein that the body can use. Excessive feeding is at
least as dangerous as underfeeding. There is a vogue for
using regimens containing immunologically active
nutrients such as arginine, glutamine, RNA and
omega-3 fatty acids; they are expensive and not well
evaluated.
Summary
• Do you understand that intensive care
depends on the availability of highly
skilled, dedicated staff, so that selection of
patients for admission must be justified by
expectation of survival with acceptable
quality of life?
• Do you recognize that intensive care is not
different from standard patient care, but
performed in an exemplary fashion?
• Are you aware of the need to adhere
strictly and unremittingly to infection
control measures?
• Will you try to alleviate the stressful
situation of the patients' families by
maintaining good communication and
support (see Ch. 47)?
General considerations
Intensive care medicine consists mainly of the vital
process of nursing patients back to health, and requires
meticulous attention to detail. Four areas deserve
mention:
1 . Nosocomial infection with resistant organisms is an
enormous problem. You must adhere strictly to infection
control measures:
a. Wash hands before and after touching every
patient.
b. Wear gloves and a plastic apron when examining a
patient.
c. Use full sterile technique, as for a surgical procedure,
when inserting a central venous catheter, both in ICU and
on the wards. This reduces catheter-related bacteraemia
rates sixfold.
2. Thromboembolism prophylaxis is needed for most
patients, usually with subcutaneous heparin. Compressive
stockings may be useful.
3. Stress ulcer prophylaxis is necessary, at least until
enteral feeding is established. On current evidence give
H 2 antagonists (Cook et al 1998). If the patient has no
history of, or special risk factors for peptic ulceration,
enteral feeding alone is adequate.
4. Patients' families are under enormous stress; try to
alleviate this with frequent, early communication and
support (see Ch. 47). It can be one of the most rewarding
aspects of working in the ICU.
References
Baldock G, Foley P, Brett S 2001 The impact of organisational
change on outcome in an intensive care unit in the United
Kingdom. Intensive Care Medicine 27(5): 865-872
Bellomo R, Chapman M, Finfer S, Hickling K, Myburgh J 2000
Low-dose dopamine in patients with early renal dysfunction:
a placebo-controlled randomised trial. Australian and New
Zealand Intensive Care Society (ANZICS) Clinical Trials
Group. Lancet 356(9248): 2139-2143
Bristow PJ, Hillman KM, Chey T et al 2000 Rates of in-hospital
arrests, deaths and intensive care admissions: the effect of a
medical emergency team. Medical Journal of Australia
173(5): 236-240
Carson SS, Stocking C, Podsadecki T et al 1996 Effects of
organizational change in the medical intensive care unit of a
teaching hospital: a comparison of 'open' and 'closed'
formats. JAMA 276(4): 322-328
Connors AF Jr, Speroff T, Dawson NV et al 1996 The effectiveness
of right heart catheterization in the initial care of critically ill
patients. SUPPORT investigators. JAMA 276(11): 889-897
Cook D, Guyatt G, Marshall J et al 1998 A comparison of
sucralfate and ranitidine for the prevention of upper
gastrointestinal bleeding in patients requiring mechanical
ventilation. Canadian Critical Care Trials Group. New
England Journal of Medicine 338(12): 791-797
Drakulovic MB, Torres A, Bauer TT, Nicolas JM, Nogue S,
Ferrer M 1999 Supine body position as a risk factor for
nosocomial pneumonia in mechanically ventilated patients: a
randomised trial. Lancet 354(9193): 1851-1858
Ghorra S, Reinert SE, Cioffi W, Buczko G, Simms HH 1999
Analysis of the effect of conversion from open to closed
surgical intensive care unit. Annals of Surgery 229(2): 163-171
396
INTENSIVE CARE
37
Gomersall CD, Oh TE 1997 Haemodynamic monitoring. In: Oh
TE (ed.) Intensive care manual. Butterworth Heinemann,
Oxford, 831-838
Klein S, Kinney J, Jeejeebhoy K et al 1997 Nutrition support in
clinical practice: review of published data and
recommendations for future research directions. Summary of
a conference sponsored by the National Institutes of Health,
American Society for Parenteral and Enteral Nutrition, and
American Society for Clinical Nutrition. American Journal of
Clinical Nutrition 66(3): 683-706
Lipman TO 1998 Grains or veins: is enteral nutrition really
better than parenteral nutrition? A look at the evidence.
JPEN. Journal of Parenteral and Enteral Nutrition 22(3):
167-182
McQuillan P, Pilkington S, Allan et al 1998. Confidential inquiry
into quality of care before admission to intensive care. BMJ
316: 1853-1858
Pupelis G, Selga G, Austrums E, Kaminski A 2001 Jejunal
feeding, even when instituted late, improves outcomes in
patients with severe pancreatitis and peritonitis. Nutrition
17(2): 91-94
Woodcock NP, Zeigler D, Palmer MD, Buckley P, Mitchell CJ,
MacFie J 2001 Enteral versus parenteral nutrition: a pragmatic
study. Nutrition 17(1): 1-12
397
Dialysis
A. Davenport
E
Objectives
Be aware of the indications for dialysis.
Understand the principles of haemodialysis
and peritoneal dialysis.
Recognize the limitations to artificial
replacement of renal function.
PRINCIPLES
■^■k^.^-^:^^
INTRODUCTION
Dialysis (Greek dia = asunder + lyein - to lose; hence
separation of substances through a septum or partition)
offers a method of treating patients with loss or severe
impairment of renal function. The membrane is synthetic
in haemodialysis but the peritoneum forms the mem-
brane in peritoneal dialysis.
Loss of the renal function threatens intracellular home-
ostasis (Greek homos - like, similar + stasis = a standing;
hence, a state of equilibrium) resulting from failure to
maintain salt and water balance. There is an additional
hormone disturbance. Erythropoietin (Greek erythros =
red + poiesis = a making) is produced by peritubular cells
in response to hypoxia. The final step in the synthesis of
active vitamin D takes place in the kidney; vitamin D
increases uptake of calcium in the gut and the resorption
of bone.
Surgical patients may present with impaired renal func-
tion. It may develop as a complication of treatment
following the stress of an operation there is increased
arginine vasopressin (also known as antidiuretic
hormone, ADH) release, resulting in water retention.
Acute renal failure may develop secondary to hypo-
volemia and /or septic shock.
The increased availability of, and survival on, dialysis
makes it likely that you will encounter patients on
dialysis requiring surgical treatment.
Fluid and chemical exchanges take place across a
semipermeable membrane (Latin semi - half or partly +
per = through + meare + to pass). On one side is natural
fluid such as blood, on the other is dialysate, a specially
formulated liquid. In peritoneal dialysis the peritoneal
mesothelium is the natural membrane; in haemodialysis
it is synthetic and the size of the pores determines what
can cross the partial barrier. Across the membrane, inter-
change takes place of water, electrolytes and other solutes
under the influence of hydrostatic and osmotic forces.
Dialysis exploits two physical principles: diffusion and
convection.
Diffusion
1. Molecules within a medium are constantly moving,
the speed determined by the temperature. As they collide,
they bounce off each other and separate. The Scottish
botanist, Robert Brown, observed the result of these col-
lisions in 1827 and this movement is named after him:
brownian movement. In an area of high concentration
there are more collisions and an increased tendency to
separate. This is diffusion (Latin dif, dis = asunder +
fundere to pour out; thus, to pour out in all directions). It
results in an even distribution of the molecules through-
out the medium (Fig. 38.1).
2. If blood is separated from prepared fluid - dialysate
- by a semipermeable membrane that permits the passage
of molecules of a substance in high concentration in the
blood, the molecules will pass through into the dialysate
provided the substance is absent or in lower concentra-
tion in the dialysate.
3. In peritoneal dialysis the membrane is the peri-
toneum; in haemodialysis the membrane is artificial and
has pores of predetermined size in order to control the
size of the molecules that can or cannot pass through.
4. In renal failure, urea, creatinine, potassium and
other waste products accumulate in the blood. Since the
dialysate used in peritoneal dialysis or haemodialysis
398
DIALYSIS
38
DIFFUSION OF SOLUTE
(MEMBRANE PERMEABLE
TO SOLUTE)
ULTRAFILTRATION DUE TO
HYDROSTATIC GRADIENT
peritoneal dialysis by increasing the osmotic pressure of
the dialysate with glucose, raising the concentration
above plasma levels.
Convection
1. Convection (Latin con = together, with + tehere = to
carry) is the transfer of substances or effects by means of
currents. In haemodialysis, as blood is pumped through
the haemodialyser, its hydrostatic pressure is higher than
that of the dialysate, so that plasma water passes through
the membrane into the dialysing fluid. Depending on the
size of the pores in the membrane, any plasma solute that
is small enough to pass through will be carried across
with the plasma water. The rate of permeable solute
removal corresponds to the solute concentration in the
plasma water (Fig. 38.2).
2. Convection also occurs across the peritoneal mem-
brane but there is no significant hydrostatic pressure dif-
ference. Therefore, the dialysate glucose concentration is
raised to increase its osmotic pressure, creating a plasma
water flow current into the dialysate (Fig. 38.3).
I * •
I
ULTRAFILTRATION DUE TO
OSMOTIC GRADIENT
(MEMBRANE IMPERMEABLE
TO SOLUTE)
Fig. 38.1 Diffusion of a solute from a region of high
concentration to one of low concentration.
contains none of these substances, the accumulated sub-
stances diffuse into it from the plasma.
5. Conversely, by adding bicarbonate to the dialysate at
a higher than plasma concentration, so that bicarbonate dif-
fuses into the plasma, metabolic acidosis can be corrected.
6. By similar adjustments of dialysate concentration,
calcium can be introduced into or extracted from, the
plasma.
7. Because the water content of both peritoneal dialy-
sis and haemodialysis fluid is greater than that of plasma,
water should diffuse from the dialysate into the plasma.
This is prevented by the relatively higher hydrostatic
plasma pressure during haemodialysis; it is prevented in
BLOOD
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1
ULTRAFILTRATE
Fig. 38.2 During haemofiltration solute moves by
convection, according to concentration in plasma water.
DIALYSIS
FLUID
Peritoneal
lining
Fig. 38.3 Peritoneal dialysis.
399
38
COMPLICATIONS
Ultrafiltration
The separation of particles by filtration under pressure or
suction is ultrafiltration (Latin ultra - beyond + filtrum =
felt - from the use of fabric formed from fibres that can be
matted together without weaving, through which to
strain liquids). Because there is very little convection
during standard haemodialysis, the transfer effect can be
increased by reducing the pressure in the dialysate com-
partment. Normal kidneys ultrafiltrate 180 litres each day
depending on the pressure difference between the renal
glomerular arteriole and the renal tubule (Fig. 38.4).
Key point
• The majority of solute (dissolved substance)
transfer during dialysis is by diffusion.
Table 38.1 illustrates what can be accomplished by the
different methods.
INDICATIONS
1. Acute dialysis may be required for:
a. Hyperkalaemia refractory to medical treatment. A
level above 6 mmol l l is dangerous; above 7 mmol H it
demands urgent correction.
b. Severe metabolic acidosis unresponsive to support-
ive treatment.
c. Pulmonary oedema not responding to medical
management.
d. Uraemia with serum urea above 30 mmol 1 _1 and /or
creatinine above 500 fimol 1 _1 , or a rise in creatinine of
more than 100 |mmol I" 1 in 24 h.
2. Chronic renal dialysis replaces long-term loss of
excretory functions. It does not, of course, replace
endocrine functions of the kidneys.
METHOJDJS^^ ^^^^^,^^^ mm ^ m
1. Kolff in Holland devised the first practical
haemodialysis machine during the Second World War.
PUMP
HAEMODIALYSIS
Fig. 38.4 Ultrafiltration can occur by applying
hydrostatic pressure during haemodialysis, or osmotic
pressure during peritoneal dialysis.
Scribner, in I960, described a practical method of vascu-
lar access by uniting the cephalic vein and radial artery
using an external shunt but this has been almost com-
pletely superseded by the side-to-side arteriovenous
fistula between the vein and artery described by Simeno
and Brescia. An alternative is a venous end-to-side anas-
tomosis into the artery. Alternative sites may be needed,
such as basilic vein to brachial artery. Care of these fistu-
lae demands skilled management by trained attendants.
2. Chronic haemodialysis is increasingly performed
using higher flux membranes than formerly, to reduce
dialysis times. In the USA, blood flow rates have been
increased up to 450 ml mrrr 1 . To decrease dialysis times
still further, ultrapure dialysate may first be administered
to maximize subsequent haemofiltration.
3. The anaemia resulting from loss of renal production
of erythropoietin can be corrected by administering
recombinant human erythropoietin.
4. Acute dialysis may be required, often on critically ill
patients.
5. Peritoneal dialysis became practical after the devel-
opment of a semipermanent peritoneal catheter by
Tenkhoff, followed by a variety of catheters and methods
of inserting them. Peritonitis may develop, presenting
with generalized abdominal pain, peritonism, absent
bowel sounds, vomiting, dehydration and pyrexia. There
is neutrophilia and cloudy peritoneal dialysate effluent.
Ta bl e 38. 1 Comparison
of modes of filtration.
Peritoneal dialysis
Solute removal
Water removal
Dialyser type
Haemodialysis
ity
Haemofiltration
Diffusion
Ultrafiltration
Low permeabil
Convection
Convection
High permeability
Diffusion
Convection
Peritoneal membrane
400
DIALYSIS
38
The diagnosis is confirmed by detecting in the dialysate,
after a 4 h dwell, more than 100 leucocytes per millilitre,
of which 90% are polymorphs. Because of changing
trends in peritoneal dialysis, it may not be possible to
differentiate between peritoneal dialysis peritonitis and
an intra-abdominal catastrophe. For this reason always
test a 4 h dwell specimen with a Gram stain. Peritoneal
dialysis peritonitis, often resulting from coagulase-
negative staphylococci, usually responds to intra-
peritoneal antibiotics; an intra-abdominal catastrophe
may demand operative intervention.
6. Peritoneal dialysis can be employed in the manage-
ment of acute renal failure. To minimize the changes in
intraperitoneal pressure, which can cause cardiovascular
instability, prefer to use small volume changes, known as
tidal peritoneal dialysis. Reduced mesenteric blood flow
in septic, hypotensive patients may prejudice solute
transfer. Because of technical problems, such as leaks,
peritoneal dialysis may not be possible following abdom-
inal operation.
counter the increased risks of cardiovascular disease in
renal failure.
Key point
The management of patients on dialysis
treatment demands skilled care from trained
attendants - to maintain the system and avoid,
anticipate, detect and treat complications.
OUTLOOK
Key points
Carefully prepare patients with renal failure
before operations by ensuring the haematocrit
is above 30%.
Ensure that the patients are well dialysed
preoperativefy.
Avoid giving low molecular weight dextrans
prior to operation because they will have a
prolonged half-life.
Summary
• Do you understand the physical principles
on which dialysis is based?
• Do you know the aims of dialysis therapy:
the maintenance of patient well-being
until acute renal failure recovers, and the
extension of life in chronic renal failure?
• Do you know what are the major methods
used in a patient with renal failure?
• Do you appreciate the deficiencies of
dialysis compared with normal renal
function?
1. The effectiveness of dialysis is not more than 7% of
that of normally functioning kidneys.
2. Increasing the amount of dialysis increases survival.
3. Because of decreased l,25(OH) 2 vitamin D 3 , patients
tend to develop secondary hyperparathyroidism. Treat
this with vitamin D analogues or patients will develop
tertiary hyperparathyroidism with bone resorption,
requiring operative treatment. It may be possible to
prevent this by injecting vitamin D analogues into the
parathyroid gland.
4. Chronic dialysis patients may develop a form of
amyloid disease owing to the deposition of E 2 microglobu-
lin. Deposits in the wrist may provoke carpal tunnel syn-
drome, in tendon sheaths causing trigger finger, in the
palm causing Dupuytren's contracture, and elsewhere in
the body.
5. The native kidney shrinks and develops cysts, which
have an increasing malignant potential.
6. The effect of uraemia in reducing platelet function
increases the risk of bleeding at operation. This may be
made worse if the patient is taking prophylactic aspirin to
Comprehensive reference
Davison AM, Cameron JS, Grunfeld JP, Kerr DNS, Ritz E,
Winearls CG (eds) 2002 Oxford textbook of clinical
nephrology, 3rd edn. Oxford University Press, Oxford
Future reading
Davenport A, Will EJ, Davison AM 1993 Improved
cardiovascular stability during continuous modes of renal
replacement therapy in critically ill patients with acute
hepatic and renal failure. Critical Care Medicine 21: 328-338
Ronco C, Bellomo R, Kellum } A 2002 Continuous renal
replacement therapy: opinions and evidence. Advances in
Renal Replacement Therapy 9(4): 229-244
Wester JP, de Koning EJ, Geers AB et al 2002 Analysis of renal
replacement therapy in seriously ill (ARTIS) investigators.
Catheter replacement in continuous arteriovenous
hemodiafiltration: the balnce between infectious and
mechanical complications. Critical Care Medicine 30(6):
1261-1266
401
Chronic illness, rehabilitation
and terminal care
A C. Kurowska, A. Tookman
Objectives
Recognize the importance of effective
communication.
Understand the principles of pain and
symptom control.
Prescribe analgesics appropriately
(especially opioids).
Be able to manage the process of dying.
INTRODUCTION
In patients with chronic illness and advanced disease,
effective symptom control forms the basis of management
(Table 39.1). For such patients the primary aim of treat-
ment is not necessarily to prolong life but to make it as
comfortable and meaningful as possible. Effective palli-
ative care enables this to happen. A significant number of
patients experience functional limitations because of their
disease or its treatment. Many of these can be treated by
rehabilitation techniques that enable them to develop to
their maximum potential.
Patients with malignancy form a large proportion of
the patients you see with chronic and terminal illness.
Since such patients present with complex problems, focus
your approach on the whole patient, rather than simply
on the disease. An interdisciplinary team approach,
including the patient and 'family', is essential to achieve
these aims.
The proportion of all deaths occurring in hospital has
increased over the last 15 years. Patients can choose the
most suitable place to spend their terminal illness if
specialist palliative care support teams are used effec-
tively. Such teams provide support and expert advice to
the professionals and other carers involved in the
patient's management. Make sure you are familiar with
your local teams both within the hospital and in the
community.
Table 39,1 Important definitions
• A terminally ill patient is one with a confident diagnosis that cure is impossible. Prognosis is usually months or
less. Treatment is aimed at relief of symptoms. Most such patients have advanced cancer, but non-malignant
disease also falls within this definition, such as the end stage of renal failure, chronic obstructive airways
disease, multiple sclerosis, acquired immune deficiency syndrome (AIDS) and motor neuron disease.
• A chronically iff patient {Greek chronos - time; hence lasting a long time) has a longer and less predictable
prognosis. Many of these patients have non-malignant disease, such as inflammatory bowel disease, peripheral
vascular disease and post-trauma. Some malignant conditions have a protracted course, such as breast and
prostatic cancer.
■ The palliative care approach (Latin palliare = to cloak; disguise, extenuate) aims to promote both physical and
psychosocial well-being. It is a vital and integral part of all cltmcaf practice, whatever the illness or its stage,
informed by palliative care principles.*
• Specialist palliative care is provided by those with palliative care as their core speciality. It is needed by a
significant minority whose deaths are anticipated; it may be provided directly through specialist services, or
indirectly through advice to the patient's normal professional advisers/carers.*
^National Council of Hospices and Palliative Care Services 1995 Specialist palliative care: a statement of
definitions. Occasional Paper 8.
402
CHRONIC ILLNESS, REHABILITATION AND TERMINAL CARE
39
P*
Key points
• Address the psychological, social, sexual,
spiritual and financial needs of the patient as
well as the physical symptoms.
• Provide effective symptom control.
• Offer control, independence and choice. This
enables the patient to participate in decisions
about management problems.
• In terminal illness this includes negotiating the
most appropriate place for the patient to die -
home, hospice or hospital.
• Support 'the family' (i.e. all those who are
important to the patient) as well as the patient.
• Provide bereavement counselling for the
terminally ill patient's 'family'.
tation as soon as the diagnosis is made. Clinical nurse spe-
cialists such as breast, stoma and incontinence advisors
play a key role.
2. Principles of good communication are to:
a. Deal with the patient's concern before yours
b. Fully cover each topic before proceeding to the
next.
c. Elicit all the problems before offering advice or
attempting solutions
d. Be sensitive to non-verbal clues
e. Clarify and summarize what the patient reports and
what is the proposed plan of action.
Key point
• It is not always a question of 'What should the
patient know?' but rather 'What does the
patient want to know?'
COMMUNICATION
Communication is difficult with patients who have
advanced incurable illness. Chronic and terminal illness
can be seen as a failure by you and so generate feelings of
inadequacy, fear and despair. These fears lead to the use
of certain tactics in order to keep patients at a safe
emotional distance (see Ch. 47):
• Premature reassurance. You reassure the patient that you
can control physical symptoms when the real issue is
the patient's underlying emotional fears.
• Selective attention. You avoid addressing the emotional
issue by selecting the physical problem for attention.
• Changing the topic when emotional issues are raised.
• Closed questions.
• Physical avoidance by zvalking past the end of the patient's
bed.
1. Give clear explanations of the physical and func-
tional outcome of surgery. Patients handle side-effects
better and gain trust in you if they understand the ration-
ale for treatment. If they are given accurate facts about
their diagnosis and treatment they adapt better to radical
surgery It gives them the opportunity to prepare psycho-
logically for the major physical changes associated with
procedures such as radical mastectomy colostomy and
head and neck surgery, thereby facilitating postoperative
adaptation. Explore issues surrounding 'loss', such as
altered body image (especially when associated with
cosmetic deformity), sexuality, social role and anxieties
related to death and dying. Be sensitive to patients' psy-
chological needs and educate them in order to ease their
acceptance of their new image and readjust their goals.
Often these issues are not discussed at all. Start rehabili-
COMMON EMOTIONAL REACTIONS
1. Anxiety is a normal reaction to a serious illness. One
of the commonest emotional reactions to a life-threatening
illness is fear. Patients with life-threatening illness com-
monly fear:
a. Unrelieved symptoms, especially pain
b. Death and the process of dying
c. Dying alone
d. Incompleted tasks (e.g. will has not been made)
e. Loss and separation (family, job, income, etc.)
f. Loss of dignity (confusion, incontinence, loss of
control)
g. Altered body image
h. Retribution in the afterlife.
Find out precisely what the patient fears, as many of the
fears on which the anxieties are based can be resolved.
Acknowledge and accept normal levels of anxiety, but
assess the patient for signs of clinical anxiety. Signs of
clinical anxiety include:
a. Persistently anxious mood, which is subjectively
different from normal worrying
b. Difficulty in distracting the patient from his or her
worries
c. Feelings of tension and restlessness
d. Insomnia
e. Autonomic hyperactivity (e.g. palpitations, sensa-
tion of choking)
f. Panic attacks.
Offer treatment with anxiolytics (Latin angere = to press
tightly + lyein = to loosen; release tension and anxiety) to
these patients.
403
39
COMPLICATIONS
2. Despair or depression are normal reactions to a life-
threatening illness. Recognize and acknowledge them.
However, look for signs of clinical depression. The classi-
cal somatic symptoms of depression, e.g. weight loss,
anorexia and lethargy, carry less importance in the assess-
ment of patients with terminal illness as they are often a
manifestation of cancer. Important clues are:
a. Persistently depressed mood, which is subjectively
different from normal sadness
b. Difficulty in distracting the patient
c. Lowering of interest in and enjoyment of social
activities
d. Crying, irritability, etc.
e. Insomnia
f . Feelings of guilt
g. Suicidal ideas may be present.
Offer treatment with antidepressants to these patients.
3. Denial. Assess whether this is causing harm, such as
refusal of necessary medication or psychological turmoil.
In many patients it represents a successful coping strat-
egy, in which case breaking down the denial may cause
unnecessary distress.
4. Anger can be displaced on to staff and /or on to the
relatives. It is important not to react with anger but to try
to accept and understand. Explain to the relatives that
the patient is not really angry with them, but is displac-
ing the anger he or she feels towards the disease, on to
them.
SYMPTOM CONTROL
^^^'^^^>?^^^<^^^-ii^^:^^^.
i$$0^^&iM$& : fe$£&
?&^&^3^^££<£tVf;
%^m , &&^fftf&^i^^
Take a positive but realistic attitude. Offer assurance that
a considerable amount can be achieved. A problem-
oriented individualized approach is the key to effective
symptom control. For each symptom, undertake the
following.
1 . Diagnose the cause and treat appropriately. An accurate
diagnosis is important for good symptom control. A
careful history and examination can be more revealing
than extensive investigations, which are often impractical
and distressing. Investigations may be important but
carry them out only if they alter subsequent management.
The treatment of a symptom varies considerably, depend-
ing on the underlying pathology. For example, in a
patient with cancer, vomiting may be due to:
a. Raised intracraiiial pressure
b. Drugs
c. Hepatomegaly
d. Intestinal obstruction, etc.
Each of these requires specific management. Since
many symptoms are multifactorial in origin, recognize
the contributory factors and tackle each as far as possible.
Other intercurrent illnesses are common in debilitated
patients, hence it is vital to consider non-malignant as
well as malignant causes. Do not assume that the
symptom is related to the primary diagnosis, as this can
lead to inappropriate management.
If the diagnosis is tentative but it is inappropriate to
investigate further, give symptomatic relief. A therapeutic
trial of drugs may be an option. For example, in a con-
fused patient with suspected brain metastases consider a
trial of steroids. If the patient improves, this is a thera-
peutic test.
2. Explain symptoms to the patient. Fear is an important
contributory factor in the patient's interpretation of any
symptom. The fact that you acknowledge the problem,
understand the symptom, can explain its cause and offer
treatment is therapeutic in itself.
3. Discuss the treatment options. Give the patient accur-
ate and balanced information that is appropriate to the
stage of the illness. This allows the patient to make
informed choices about treatment and possible options,
thereby enhancing his or her sense of control. Treatment
with a palliative intent need not be limited to drugs.
Other measures, such as surgery, radiotherapy, nerve
blocks, physiotherapy psychological therapy such as
counselling and hypnotherapy, may be indicated.
4. Set objectives that are realistic. It is frustrating for both
patient and staff alike if expectations are set that will
never be achieved.
5. Anticipate. With advancing illness, symptoms
(Table 39.2) may change rapidly. If such changes are
anticipated, much distress may be avoided. For example,
deterioration in a patient's condition with a progressive,
advanced cancer may make it impossible for the patient
to continue with oral medication. Such deterioration
Table 19.2 Common symptoms in patients with
advanced cancer
Symptom
Approxir
incidenci
Physical
Weakness
80
Pain
70
Anorexia
70
Dyspnoea
50
Cough
50
Constipation
50
Nausea and vomiting
40
Psychological
Depression
30
Anxiety
30
404
CHRONIC ILLNESS, REHABILITATION AND TERMINAL CARE
39
should be anticipated and injectable preparations should
be available. This particularly applies in the home care
setting and can avert an unnecessary crisis.
6. Ensure relatives remain informed and supported. It is
important to treat the 'whole family'.
PAIN
$t^&?&$&&$&
Pain is a common symptom in chronic and terminal
illness and one that is particularly feared by cancer
patients. Pain can be alleviated or modified in all
patients. Proper pain assessment leads to effective man-
agement. The principles outlined here have been devel-
oped in the context of management of patients with
advanced cancer, but are applicable to patients who have
non-malignant pain secondary to chronic disease (see
Ch. 35).
Diagnose the cause
The majority of patients with far advanced disease
have pain at more than one site. Evaluate each pain
individually.
In order to establish the cause of any pain, take a careful
history, particularly noting:
• The site of pain and any radiation
• The type and severity of pain
• When the pain started and any subsequent changes
• Exacerbating and alleviating factors
• Analgesic agents already used.
Physical examination often confirms the diagnosis. If
appropriate, investigate the patient with X-rays, isotope
bone scans, CT scans, etc.
Key point
• Pain may be due to a malignant cause but in
up to a third of patients with advanced cancer
the underlying cause is non-malignant.
Always assess how significant the pain is for the indi-
vidual patient - how does it affect and alter his or her
life-style?
Common causes of pain in cancer patients
Pain in patients with advanced disease is often complex
because it can be due to multiple pathologies. An accurate
assessment of the cause of the pain leads to more effective
management.
• Bone pain from metastatic disease or local infiltration by
adjacent tumour is characteristically a deep gnawing
pain made worse by movement. The bone is often
tender on percussion.
• Visceral pain from a tumour mass in the lung or internal
organs of the abdomen or pelvis causes pain by a
variety of mechanisms:
- Soft tissue infiltration causes deep-seated pain due to
complex pathology. The tumour invades and /or
stretches pain-sensitive structures such as parietal
and visceral pleura, peritoneum, nerve plexuses, and
local bony structures.
- Stretching of a capsule of an organ is painful. The most
common example is right hypochondrial pain due to
stretching of the liver capsule. It can be very severe,
and a sudden exacerbation of pain may stem from a
bleed into a local deposit.
- Stretching of a hollow organ, such as small and large
intestines, bladder or ureters, can cause severe
spasmodic colicky pain.
• Nerve pain from irritation, infiltration and /or compres-
sion is often a deep ache. Nerve destruction pain may
be burning, lancinating and associated with abnormal
sensations such as hyperesthesia. When there is
destruction of nerve plexuses, nerve roots or peripheral
nerves, deafferentation pain may result. This type of
pain is not uncommon and often coexists with visceral
and somatic pain. Deafferentation pain is characterized
by unpleasant pain that is difficult to describe. It is
often associated with sensory changes in the painful
area and patients complain of allodynia (pain that is
evoked by a non-painful stimulus, such as stroking
skin lightly).
• Myofascial pain. Musculoskeletal pains are common
in chronically ill patients. They radiate in a non-
dermatomal pattern. Typically there are localized
hypersensitive areas of muscle known as trigger points,
which are tender to pressure.
• Superficial pain may develop in weak, debilitated
patients; bedsores may be unavoidable and give rise to
distressing pain.
Realistic objectives
Pain can be significantly modified in nearly all patients
and fully relieved in many. In a few of them it can be
intractable and unresponsive to most treatments. These
patients provide the greatest challenge so explore all
avenues of achieving pain relief. Invariably involve your
local specialist palliative care team in the management of
these patients. Pursue realistic objectives. You should
always be able to achieve freedom from pain at night,
usually freedom at rest. Sometimes you may not succeed
in relieving pain on mobility.
405
39 1
COMPLICATIONS
Treat pain appropriately.
Not all pain requires analgesia; for example, the pain of
constipation is best treated with laxatives, not analgesics.
However, when analgesics are indicated, prescribe them
correctly.
Analgesic treatment of pain
The variety of analgesics available for use in the treatment
of pain can be daunting. It is better to use a few drugs
really well than many badly. The following 'three-step'
regimen is effective in the majority of situations:
STEP 1 Non opioid +/- adjuvant, such as paracetamol.
If the pain is not relieved with 2 paracetamol 6-hourly
move on to:
STEP 2 Weak opioid +/- adjuvant, such as paracetamol/
dextropropoxyphene / paracetamol /codeine, tramadol.
If the pain is not relieved with 2 co-proxamol (or equiva-
lent) 6-hourly move on to:
STEP 3 Strong opioid +/- adjuvant, such as morphine
sulphate immediate release, morphine sulphate slow
release, diamorphine subcutaneously.
Principles of prescribing opioids
• Give morphine orally unless the patient cannot tolerate
oral medication.
• Prescribe it regularly to pre-empt pain. An 'as-required'
basis results in poor pain control, increased incidence
of side-effects and the use of higher doses overall.
• Give it an adequate trial at an adequate dose.
• Coprescribe extra doses for breakthrough and incident
pain to be used as necessary - pro re nata (Latin =
according to the condition arising, born).
• Side-effects should be anticipated so that they can be
prevented.
Prescibe p.r.n. doses of analgesic for:
• 'Breakthrough' pain - that breaks through the
background analgesia. Daily use of
breakthrough analgesics implies the regular
dose of analgesic is not adequately controlling
the pain so increase it accordingly.
• 'Incident' pain - that is precipitated by painful
incidents such as dressing changes. The need
for p.r.n. analgesics for incident pain does not
imply that background pain is inadequately
controlled. Therefore do not increase regular
analgesics; this might increase side-effects.
Strong oral opioids of choice
1. Morphine sulphate as tablets or solution are quick-
acting preparations. Prescribe 4-hour ly day and night.
The short duration of action means there is rapid response
to alterations of dose. Use them when the patient first
starts on opioids in order to estimate the overall opioid
requirement for that individual.
2. Morphine sulphate controlled release is a long-
acting preparation. Prescribe it 12-hourly. When the
patient's pain is stable on 4-hourly morphine convert to
the equivalent dose of morphine sulphate controlled
release to simplify the regimen.
3. If the pain is only moderate and urgent control is not
necessary, you may start the patient on morphine sul-
phate controlled release initially
4. The above two morphine preparations are suitable
for most patients. Other strong opioids have a role in
pain management (Table 39.3). These drugs are generally
used when morphine is contraindicated or when opioid-
sensitive pain has become resistant to morphine, when
:
Table 393 Alternative opioids
* Fentanyi This is available in a transdermal preparation, Change the patch every third day, It takes several days
to reach steady state (biological haJf-JHe of 17 h). It is therefore not indicated in patients who need quick
titration nor in the opioid naive. It is particularly useful in patients who cannot swallow, who have absorption
problerns or who are poorly compliant with oral medication. It is metabolized in the liver to inactive
metabolites and is therefore useful in patients with renal dysfunction. It is said to cause less constipation than
morphine. Switching between transdermal fentanyi and other opioids can be difficult; conversion tables are
only a guide.
* Hydromorphone. This ts similar to morphine but 7.5 times more potent. Its metabolites are less active than
morphine metabolites,
* Methadone. Long acting opioid which may have a useful role in neuropathic pain. (Although opioids are said
to be ineffective la neuropathic pain, clinical experience challenges this.) Its long half-life makes it a difficult
drug to use because accumulation can occur,
■ Oxycodone. A step ll/lll analgesic with inactive metabolites.
406
CHRONIC ILLNESS, REHABILITATION AND TERMINAL CARE
f 39
Table 39.4 Relative potency of opioids
Opioid
Relative oral potency
(for repeated dosing)
Typical starting dose
Morphine
1
Codeine
0.1
Dihydrocodeine
0.1
Pethidine
0,125
Tramadol
0.2
Methadone
4-5
Hydromorphone
7.5
Fentanyl
250
10 nig 4-hourly
30 mg 6-hourly
30 mg 6-hourly
50 mg 4-hourly
50 mg B-hourly
5 mg 8-hourly
1,3 mg 4-houriy
25 mg h _1 72-hourly
Equipotent morphine dose
(approx, - great individual variation)
10 mg
3 mg
3 mg
6.25 mg
10 mg
20-25 mg
10 mg
10-20 mg
4-hourly
morphine has been unexpectedly ineffective or when
morphine is causing too many side-effects. They are
generally second-line agents.
5. The dose depends on previous analgesic require-
ments:
a. If not on any previous analgesic, start with 2.5 mg
morphine 4-hourly or 10 mg morphine sulphate slow
release 12-hourly
b. If on weak opioid (e.g. co-proxamol) start with
5-10 mg morphine 4-hourly or 30 mg morphine sulphate
slow release 12-hourly.
c. If on other strong opioid, use Table 39.4 to convert
to equivalent dose of morphine 4-hourly. Titrate the dose
as indicated by the level of pain control achieved.
Key points
• Treat significant pain with early, adequate,
effective analgesics.
• Don't waste a terminally ill patient's time using
ineffective moderate analgesics.
• Opioids are the most effective strong
analgesics.
Routes of administration
1. If the patient is able to swallow, use the oral route.
However, at times it may be necessary to give opioids
transdermally or parenterally; opioids can be given
rectally, but this route is rarely necessary.
2. Indications for transdermal /parenteral opioids:
a. In the last few hours/ days of life when the patient is
unable to swallow
b. Dysphagia
c. Nausea and vomiting
d. Gut obstruction
e. Unable to tolerate taste/number of tablets.
3. Parenteral opioids. Diamorphine hydrochloride is
highly soluble (1 g in 1.6 ml). It is the drug of choice for
parenteral use because of the small volume needed.
Subcutaneous injections are effective and this is the route
of choice. Diamorphine undergoes first-pass metabolism
in the liver, hence the subcutaneous dose should be half
to one-third the oral dose.
4. If the patient is going to require more than two or
three injections, consider a subcutaneous infusion pump.
This is a small battery-driven device that injects the con-
tents of a syringe over a 24 h period. It can be used in the
home as well as in the hospital (Table 39.5).
5. Transdermal opioids. Fentanyl patches may occa-
sionally be used in preference to subcutaneous infusion
(see above under alternative opioids).
Fears of prescribing opioids
Fears about prescribing opioids are common and may
lead to patients having effective analgesia withheld. Both
professionals and patients have unfounded anxieties
Ta b I e 3 9 ■ . 5 Eq u iva lent dose of opioid s
Equivalent doses of opioids
(Dose of oral morphine:dose of injected
diamorphine = 2:1 or 3:1)
10 mg morphine sulphate orally 4-hourly
(60 mg oral morphine in 24 h)
is equivalent to
30 mg slow release morphine twice a day
(60 mg oral morphine in 24 h)
is equivalent to
5 mg of diamorphine s.c. 4-hourly
(30 mg s.o diamorphine in 24 h)
is equivalent to
30 mg diamorphine in a 24 h sx. infusion (syringe
driver)
407
39
COMPLICATIONS
about opioids. An understanding of these myths will lead
to improved communication, more appropriate analgesic
prescribing and better compliance.
1. Fear of addiction. It has been shown in many studies
that psychological addiction does not occur. Patients
reduce and /or stop their opioid if their pain is controlled
by another method (e.g. nerve block, surgical fixation).
Since chemical dependence occurs (as is the case with
many drugs), morphine should be gradually reduced. It
must never be stopped abruptly.
2. Fear of tolerance, which occurs only to a minor degree
and for practical purposes is not relevant. If the dose of
opioid needs to be increased, it is as a result of an increase
in pain secondary to disease progression.
3 . Fear of respira tory depression but with careful attention
to dosage this does not occur. In fact opioids are used in
palliative care to alleviate dyspnoea by reducing ventila-
tory demand and hence the sensation of breathlessness.
4. Fear of hastening death. Opioids do not hasten death
when correctly prescribed. The exhaustion caused by
unrelieved pain may do so.
5. Fear that a morphine prescription signals that death is
imminent. This is a common anxiety for patients, who may
believe that a morphine prescription is given only when
the doctor feels that death is imminent and has kept this
information from them.
Predictable side-effects of morphine/
diamorphine
• Constipation occurs in >95% of patients. Prescribe a
regular prophylactic laxative.
• Nausea and vomiting occur in approximately 20% of
patients. An antiemetic should be prescribed if nausea
or vomiting occurs but it is not necessary to prescribe
antiemetics prophylactically. The antiemetic of choice
for opioid-induced nausea is haloperidol. Nausea due
to opioids is usually self-limiting so the antiemetic can
be withdrawn after 10-14 days.
• Drowsiness occurs in about 30% of patients. This side-
effect wears off after approximately 5 days on a stable
dose.
• Other side-effects. These include dry mouth, which is
very common and should be treated with simple local
measures; confusion and hallucinations are rare (<1%
of patients) and other causes should be excluded;
twitching can occur on high doses.
Key points
Morphine and its metabolites are dependent
on the kidney for excretion.
• Toxicity will result unless you adjust the dose
for a patient with renal dysfunction.
Opioid-resistant pain
Some pains are either partially sensitive or insensitive to
opioids. These pains will need to be managed with an
additional or alternative drug or some other technique.
Bone pain. Although partially sensitive to opioids,
bone pain frequently requires the addition of a non-
steroidal anti-inflammatory drug. Localized bone pain
can often be treated with radiotherapy. Surgical fixation
may be indicated if there is a pathological fracture.
Consider prophylactic fixation if more than 75% of the
cortex is eroded, because a spontaneous fracture is highly
likely. Generalized bone pain in malignancy may need
systemic therapy with bisphosphonates. Chemotherapy,
hormone therapy and strontium-89 all have a role in the
management of bone pain.
Nerve pain. This is very often opioid insensitive;
however, a trial of opioid is usually indicated.
Methadone seems to be particularly effective. Steroids
are useful in nerve compression. Nerve infiltration/
irritation /destruction pain may respond to drugs that
alter neurotransmission (e.g. low dose tricyclic anti-
depressants, anticonvulsants, membrane stabilizers).
Radiotherapy and nerve blocks may also be indicated.
Liver capsule. This pain is partially opioid sensitive.
Steroids are very useful in this context as they may reduce
liver swelling and relieve capsular stretching.
Colic. If caused by constipation, this demands treat-
ment with laxatives. Stop drugs causing hyperperistalsis.
Colic from tumour obstruction may respond to antispas-
modics.
Meningeal pain/raised intracranial pressure.
Steroids are the drug of choice. Consider using
radiotherapy.
Lymphoedema. Non-steroidal anti-inflammatory
drugs and steroids can be helpful. Physical treatment
plays an important role (massage, compression hosiery
and manual lymphatic drainage).
Muscle Spasm. Benzodiazepines or baclofen can be
used.
Infection. It may be appropriate to treat infections in
order to relieve pain.
Jointfmyofascial pain. Use non-steroidal anti-
inflammatory drugs in conjunction with opioids. Local
injections of steroid into joints and trigger points may be
of value. Physiotherapy can also be helpful.
Superficial pain. Patients with bedsores need to be
kept off the pressure areas with regular turning. An effec-
tive mattress to support the patient is essential.
Psychological pain. If management is solely
directed at physical factors, you may fail to control pain
408
CHRONIC ILLNESS, REHABILITATION AND TERMINAL CARE
f 39
adequately in some patients. It is important to treat co-
existent depression or anxiety, and if appropriate offer
counselling and diversionary activities.
Complementary therapies
Although scientifically unproven, these seem to benefit
some groups of patients. If the patient perceives these thera-
pies as adding to their overall well-being then support the
patient, provided the treatment does no harm and does
not interfere with their conventional management.
Injection techniques in cancer pain
Nerve blocks have a place in palliative care. They are
highly effective when used in a selected group of patients
(approximately 4% of patients with pain will benefit).
Consider using nerve blocks for:
• Unilateral pain
• Localized pain
• Pain due to involvement of one or two nerve roots
• Abdominal pain arising from 'upper' gut
• Rib pain.
1. Carefully assess the cause of the pain before carry-
ing out a block and determine the exact site at which the
pain pathways should be interrupted.
2. Many procedures can be performed using local
anaesthetics and steroids. These blocks can give good pain
relief, outlasting the effect of the anaesthetic, and they are
safe procedures. The pain relief from a nerve block may
be transient and repeated blocks may be necessary.
3. Select the patient carefully and offer a nerve block
only if there is a reasonable chance of success.
4. In addition to neural blockade, spinal analgesics
have an important role in selected cases. Epidural and
intrathecal administration of opioids (and local anaes-
thetics) by a catheter system are particularly useful in
patients with opioid-sensitive pain who are experiencing
unacceptable side-effects with systemic therapy.
5. Major neurolytic procedures may carry the risk of
serious side-effects, so first assess the patient carefully.
For example, intraspinal neurolysis for nerve root pain
can produce urinary and faecal incontinence. Coeliac
plexus block for upper abdominal pain can cause postural
hypotension.
debility it is very difficult to treat. Exclude reversible
causes such as cord compression and cerebral met-
astases. Acknowledge the problem and explain to the
patient that it is a result of the illness. This allows realis-
tic goals to be set, which in itself can reduce the patient's
distress. Even very sick patients need to feel a sense of
control. Simple measures such as a wheelchair can help
them achieve this.
2. Steroids improve weakness in a proportion of
patients. The response, however, is often short lived so
take into account side-effects such as proximal myopathy
and poor wound healing. Select patients carefully and
assess the time at which steroids are introduced.
3. A patient who is immobile and confined to bed loses
muscle strength. A normal person loses 10-15% of muscle
strength when completely rested for 1 week and it takes
60 days to restore that strength. It is therefore not sur-
prising that muscle weakness quickly develops in the
immobile cancer patient, especially in the common situ-
ation where protein catabolism is increased. If immobil-
ity continues, contractures can develop, leading to
impaired ability to self -care. Contractures are more likely
when soft tissue damage is present and with improper
positioning in bed. Good nursing care and regular
physiotherapy are essential for these patients.
4. When patients are debilitated and immobile, pres-
sure sores can rapidly develop. This is aggravated by
increased protein catabolism and negative nitrogen
balance as well as other factors (e.g. diabetes, steroids).
Damage can be minimized if pressure on the skin is inter-
mittent. Limit the damage and prevent the consequent
pain by early prophylaxis with scrupulous nursing atten-
tion and the use of effective patient support systems (e.g.
special mattresses, low-loss airbeds).
5. Autonomic dysfunction and impaired peripheral cir-
culation are the cardiovascular consequences of immo-
bility. There is an increased likelihood of deep venous
thrombosis and pulmonary embolism.
6. Atelectasis results from reduced aeration of the pos-
terior lungs and predisposes patients to chest infection.
7. Urinary retention and urinary infection are more
common in immobile patients.
8. Immobility, anorexia and weakness lead to reduced
peristalsis and constipation.
9. Loss of proprioceptors in the skin of the feet will lead
to an inability to balance, which can take many weeks to
recover.
<^^^ft^^&$$&tt#
sreciFicre
Weakness and immobility
1 . Weakness is a common and distressing symptom in
patients with advanced illness. When due to general
Anorexia
1. This occurs in approximately 70% of patients with
advanced cancer. It is important to decide whose problem
it is - the patient's or the carers'. The family need to
understand that as death approaches it is normal to lose
409
39
COMPLICATIONS
interest in food. At this stage the goal of eating is enjoy-
ment, not optimal nutrition.
2. Causes of anorexia are:
a. Tumour bulk and associated biochemical abnormal-
ities (hypercalcaemia, uraemia, etc.)
b. Oral problems (e.g. thrush, oral tumour)
c. Constipation
d. Drugs, radiotherapy
e. Depression or anxiety.
3. Remember that fear of vomiting may lead to avoid-
ance of food, as opposed to true anorexia. Psychological
factors such as anxiety and depression can manifest as
lack of appetite. Presentation of food is important - it
should be in small portions and well presented.
If the above factors have been attended to and it is still
felt to be a problem for the patient, consider progestogens
or steroids as appetite stimulants.
Dysphagia
1. The site of dysphagia can be predicted from the
symptom complex. Drooling, leaking of food and reten-
tion of food in the mouth indicate a buccal cause; nasal
regurgitation, gagging, choking and coughing suggest
pharyngeal pathology; a sensation of food sticking
behind the sternum and pain between the shoulder
blades imply oesophageal obstruction.
2. It is important to explain the cause (Table 39.6) to the
patient so that any dietary adjustments are understood. If
necessary, restrict intake to liquids or soft foods.
3. Treat any associated pain. Mucaine is useful for the
local pain of Candida or radiotherapy, but many patients
require opioids for satisfactory pain relief. Actively treat
Candida with topical or systemic antifungals. If patients
are unable to swallow even liquids, give drugs by another
route. A subcutaneous infusion of drugs (analgesics, etc.)
is both effective and well tolerated.
4. If it is appropriate to attempt to relieve the obstruc-
tion, then possibilities include radiotherapy, endo-
oesophageal tubes, stents, dilatation and laser therapy.
Steroids, by reducing oedema, may palliate dysphagia for
a significant period. They can be particularly useful in the
management of dysphagia syndrome associated with
head and neck tumour. Consider endo-oesophageal tubes
and stents in patients who are relatively independent and
active; they are not for the moribund. Percutaneous gas-
trostomy may be an option in patients with incurable
malignant obstruction but it does not solve the problem
of saliva aspiration. There is a significant morbidity asso-
ciated with percutaneous gastrostomy insertion, so select
patients carefully.
5. In irreversible total obstruction or terminal neuro-
muscular dysfunction reduce secretions to a minimum
using hyoscine.
6. Regard dehydration as a natural process in the last
few days of life. It can help relieve a number of symp-
toms. Intravenous fluids may exacerbate discomfort by
increasing bronchial secretions, gastrointestinal fluid
(increased likelihood of vomiting), urine flow (leading to
need for catheter), etc. However, hydration may be indi-
cated in selected patients, for example if a patient is com-
plaining of thirst /dryness. Usually these patients can be
managed with subcutaneous fluids, preventing the
repeated trauma of cannulation.
Nausea and vomiting
1 . These occur in approximately 40% of patients with
far-advanced cancer. Find the cause in order that rational
treatment can be offered (Table 39.7).
2. If an antiemetic is needed, most nausea and vomit-
ing in patients with advanced illness can be controlled
using the antiemetic drugs in Table 39.8. Most antiemet-
ics act at one of the sites shown in the table. Sometimes
more than one antiemetic is necessary. If this is the case it
is common sense to combine drugs that act at different
sites, i.e. a neuroleptic with an antihistamine.
Table 39,6 Common causes of dysphagia in patients with advanced disease
Problem
Sofids then liquids
Solids and Jiquids
simultaneously
Painful
Implication
Obstruction
Neuromuscular cause
Mucosal causes
— i
Example of cause
Tumour mass
External compression
Terminal neuromuscular dysfunction in very weak patients
Perineural tumour infiltration with head and neck tumours
which damage cranial nerves {V, IX, X)
Bulbar palsy
Candida (Note: only 50% of patients with oesophageal
Candida have clinically apparent oral Candida)
Post-radiotherapy
410
CHRONIC ILLNESS, REHABILITATION AND TERMINAL CARE
39
Table 39,7 Common causes of nausea and vomiting in advanced cancer
Cause
Symptomatic treatment
Drugs
If possible withdraw the drug
Metabolic (hypercalcaemia, uraemia, etc.)
Treat with centrally acting antiemetic
Bowel obstruction
Centrally acting antiemetic (see below)
Squashed stomach syndrome*
Prokinetic antiemetic, proton pump inhibitor/H- antagonist
Gastric irritation (e.g. NSAIDs, gastric ulceration}
Prokinetic antiemetic, proton pump inhibitor/H 2
antagonist7misoprostol
Constipation
Laxatives
Liver metastases
Centrally acting antiemetic/sterotds
High bulk disease
5teroids, centrally acting antiemetic/ondansetron
Raised intracranial pressure
Steroids
NSAIDs, non-steroidal anti-inflammatory drugs.
* Squashed/small stomach syndrome is a constellation
of alimentary symptoms seen in patients with a large
epigastric mass/gross hepatomegaly. It is manifested
as early satiation, epigastric fullness, flatulence, hiccoughs,
nausea, vomiting and heartburn.
Table 39.8 Sites of action of antiemetic drugs
Main site of action
Class of drug
Example
Central
Chemoreceptor trigger zone
Neuroleptic
Haloperidol
Vomiting centre
Antihistamine
Cyclizine
5HT3 receptors
5HT3 receptor anta
gon
ists
Ondansetron
All central sites
Phenothiazine
Levomepromazine
Peripheral
Prokinetic
Domperidone
3. The antiemetic must be delivered by a suitable route.
There is little point in giving a drug orally if the patient is
vomiting! Choose rectal or parenteral routes in these
situations. A 24 h subcutaneous infusion by means of a
syringe driver is a simple and effective method of drug
delivery. (Syringe drivers are discussed in more detail
later.)
Bowel obstruction
1. Gastrointestinal obstruction occurs in approxi-
mately 4% of patients with advanced cancer, more com-
monly in those with colonic primary (10%) and ovarian
primary (25%). Manage these patients surgically if they
are in good general condition, if they have low-bulk
disease and if an easily reversible cause seems likely. Take
into account previous laparotomy findings. Surgery
remains the primary treatment because in selected
patients 10% of obstructions prove to be non-malignant,
10% represent a new primary and approximately 60%
will not reobstruct
2. With conservative treatment, 30% of obstructions
resolve spontaneously. Therefore consider this manage-
ment prior to proceeding to surgery. The medical man-
agement of bowel obstruction is given in Table 39.9.
3. Do not resort to either of these strategies as part of
the primary management of irreversible obstruction in
patients with far-advanced cancer. The majority of such
patients have obstruction at multiple sites. Aim for
symptom control with drugs. Intravenous fluids and
nasogastric tubes are rarely needed.
4. Obstruction may be proximal, in which case the pre-
dominant symptom is vomiting, or distal, when the pre-
dominant symptom is colicky pain. Nausea is often more
411
39
COMPLICATIONS
Table 39.9 Medical management of bowel obstruction
Diet
Nausea and vomiting
Reverse obstruction
Pain
Colic
No restrictions but small meals appropriate.
Cyclizine 1 50 mg per 24 h via syringe pump. If partial/no success combine with
haloperidol 5-10 mg per 24 h in syringe pump. Octreotide via the subcutaneous
route has an important role in bowel obstruction, particularly in high vofume
vomiting.
If constipated, attempt to clear with softeners. Docusate 100-200 mg t.d.s. Consider
dexamethasone 16 mg per 24 h by subcutaneous infusion to reduce oedema. In
certain cases, e.g. cancer of the ovary, chemotherapy may be effective.
Diamorphine in appropriate dose in syringe pump according to previous analgesic
requirement and level of pain.
If colic persists despite the above, add hyoscine butylbromide 60-120 mg per 24 h to
pump. Octreotide is helpful by decompressing the bowel and reducing the
distension.
Gastrokinetic antiemetics such as metoctopramide or domperidone are contraindicated - they wilt exacerbate
vomiting.
distressing than vomiting. The aim is to eliminate nausea,
reduce vomiting to a maximum of once or twice a day and
treat associated pain. Baines et al (1985) reported on this
form of management in 38 patients with advanced malig-
nant disease. They found that nausea and vomiting was
well controlled in 90% of patients, colic in 100% and pain
relief was total in 90 %, with only mild residual pain in
10%. The median survival was 3 months and 24% sur-
vived >6 months.
Syringe drivers in symptom control
Syringe drivers delivering subcutaneous infusions of anal-
gesics, antiemetics, anticholinergics or tranquillizers are
commonly used in patients who require regular parenteral
medication (Table 39.10). The subcutaneous route is
simple, safe, effective and acceptable to most patients.
Indications for the use of such syringe drivers have already
been discussed above in the context of pain control.
Constipation
The need to treat constipation is usually a consequence of
failing to use prophylactic laxatives (virtually all patients
on opioids should have a regular laxative). A rectal exam-
ination is essential on any patient complaining of consti-
pation or diarrhoea to assess for impaction.
TERMINAL PHASE MANAGEMENT
1. When a patient who has advanced illness enters into
the terminal phase, normally a day or so prior to death,
review all medication. Stop all drugs apart from those
aimed at symptom control.
Reason for drug
Analgesia
Colic
Antiemetic
Bronchial secretions
Anxiolysis
Terminal agitation
Other drugs
>nly used in a continuous 24 h subcutaneous infusion
■ r-T— _^_i.
pump
Drug
Dose in 24 h
Diamorphine
According to need
Hyoscine butylbromide
30-60 mg
Halopehdo!
5-10 mg
Cyclizine
150 mg
Levomepromazme
12.5-25 mg
Hyoscine hydrobromide
1.2-1,8 mg
Hyoscine butylbromide
30-120 mg
Glycopyrrolate
0,6-1.2 mg per 24 h
Midazolam
5-10 mg
Midazolam
15-60 mg
Levomepromazine
100-200 mg
Dexamethasone
0.5-16 mg
Octreotide
300-1200 M .g
412
CHRONIC ILLNESS, REHABILITATION AND TERMINAL CARE
39
2. Communication is vital. Explain to the patient and
the carers about anticipated changes in the patient's
condition. Offer reassurance that symptoms will remain
controlled and the patient kept comfortable. Often it
is appropriate to use a syringe driver to administer
medications.
3. Continue analgesia even if the patient becomes
unconscious. The patient may still perceive pain and, in
addition, abrupt withdrawal of opioids can result in an
unpleasant physical withdrawal reaction. If a patient is on
regular opioids, these will need to be continued at an
equivalent dose subcutaneously. If the patient will require
more than a few injections, start a syringe driver.
4. Agitation. Search for the causes and treat them if
indicated; for example, retention of urine requires
catheterization. However, it is not uncommon for
patients to become agitated and confused shortly before
death. If a tranquillizer is indicated, use subcutaneous
midazolam (5-10 mg, 4-6-hourly). Midazolam (20-60 mg
per 24 h) can be combined with diamorphine in a syringe
driver.
5. Bronchial secretions can be controlled using subcu-
taneous hyoscine or glycopyrronium, as required. Either
can also be added into the syringe driver together with
diamorphine and midazolam.
6. Crises. In some circumstances it may be appropriate
to prescribe drugs for an anticipated crisis such as a
massive haemoptysis or rupture of a major vessel. Such
crises cause great distress to the patient and the family, so
handle them speedily and sensitively. Prescribe midazo-
lam with or without diamorphine as required, and give
the nurses instructions to give it immediately should such
an "end of life' crisis occur.
Key points
• Always follow the rules of symptom control
throughout.
• Evaluate symptoms and treat them
appropriately.
• Anticipate crises.
• Communicate.
• A peaceful death alleviates the severity of
bereavement in the family
Bereavement
1. Provide support for the family both during the
patient's illness and at the time of death. It helps them to
cope better and also reduces the likelihood of future com-
plications. Evidence suggests there is higher physical and
psychiatric morbidity and possibly increased mortality in
those recently bereaved.
2. People avoid grieving individuals because they feel
helpless, awkward, embarrassed, they do not wish to feel
sad themselves and they fear releasing strong emotions.
Bereavement counselling
1. Identify those who are likely to have a difficult
bereavement, as they are at risk of developing psychiatric
illness in the bereavement period, such as psychosis,
clinical depression or extreme anxiety states. Some indi-
viduals may resort to alcohol, drugs, denial, idealization,
etc. as a way of coping with loss. Refer them early to the
appropriate agency, such as a psychiatrist or bereavement
counsellor.
2. Individuals at increased risk of difficult bereavement
include those:
a. With a close, dependent or ambivalent relationship
b. Undergoing concurrent stress at the time of
bereavement
c. With memories of a 'bad' death (e.g. uncontrolled
symptoms)
d. Who have a perceived low level of support (the
carer's perception is more important than the actual
support in determining outcome)
e. Experiencing strong feelings of guilt /reproach
f. Unable to say goodbye, who feel there are things left
unsaid (e.g. sudden or traumatic deaths or absence at the
time of death).
Summary
• Do you recognize the essential importance
of clear, effective communication?
• Will you determine to treat the whole
patient not just the disease?
• Do you intend to assess fully each
symptom before prescribing treatment
and revise it as the disease progresses?
• Do you feel confident that you can control
or modify pain?
• Do you recognize the value of using
morphine sulphate as the first choice
when a strong opioid is indicated?
• Will you continue to control symptoms
with analgesia, sedation and antisecretory
drugs for excessive respiratory secretions
during the terminal phase?
• Will you remember to call upon the
expertise of your local palliative care
team/hospice?
413
COMPLICATIONS
References
Baines M, Oliver DJ, Carter RL 1985 Medical management of
intestinal obstruction in patients with advanced malignant
disease: a clinical and pathological study. Lancet ii: 990-993
Further reading
1 998 Directory of hospice and palliative care services in the
United Kingdom and Republic of Ireland. Hospice
Information Service, St Christopher's Hospice, London
Buckman R 1992 How to break bad news: a guide for health
care professionals. Papermac, London
Doyle D, Hanks WC, Macdonald N 1998 Oxford textbook of
palliative medicine. Oxford University Press, Oxford
Faulkner A, Maguire P 1994 Talking to cancer patients. Oxford
Medical Publications, Oxford
Kaye P 1996 Breaking bad news. (Pocket Book) EPL
Publications, Northampton
Parkes CM 1972 Bereavement: studies of grief in adult life.
Tavistock and Pelican, London; International Universities
Press, New York
Regnard C, Davies A 1986 A guide to symptom relief in
advanced cancer. Haigh and Hochland, Manchester
Stedeford A 1985 Facing death. Heinemann, London
Twy cross RG 1997 Symptom management in advanced cancer.
Radcliffe Medical Press, Abingdon, Oxfordshire
Twy cross RG, Lack SA 1986 Control of alimentary symptoms in
far advanced cancer. Churchill Livingstone, Edinburgh
Twycross RG, Wilcock A, Thorp C 1998 PCF1 Palliative care
formulary. Radcliffe Medical Press, Abingdon, Oxfordshire
414
SECTION 8
415
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Genetic aspects of surgery
M. C Winslet
W
Objectives
Recognize genetic disorders which may
produce life-threatening complications
during surgery and anaesthesia:
- defects of haemoglobin and haemostasis
- defects of muscle
- defects of connective tissue
- skeletal dysplasias.
Become familiar with the disorders leading
to a genetic susceptibility to cancer.
RELEVANCE TO SURGERY
In certain genetic disorders life-threatening complications
may occur during surgery and anaesthesia. Recognize
family history and clinical signs suggestive of these
genetic disorders in order to plan appropriate peri-
operative management. It is now possible to study the
molecular basis of genetic disorders, human develop-
ment, carcinogenesis and many other biological events.
This stems from exciting advances in laboratory tech-
niques for the analysis of the human genome.
Genes involved in the control of cell proliferation and
transcription of genetic information have been shown to
cause increased susceptibility to cancer if their function is
defective. Thus, genetic analysis and the development of
new methods for clinical diagnosis, monitoring of cancer
progression and treatment are being reported in medical
literature and incorporated in clinical medicine. These
advances clearly illustrate the link between basic sciences
and clinical practice. They emphasize your need to under-
stand basic genetic concepts in order to keep abreast of
new developments.
BASIC CONCEPTS AND TERMINOLOGY
&£&&&&&?&$&?,
1. Genes are units of genetic information which are
passed on from generation to generation. Biochemically,
genes are stretches of DNA (deoxyribonucleic acid) which
direct the synthesis of a specific protein.
2. DNA is tightly coiled and packaged in chromosomes,
which are visible under the light microscope in the
nucleus of dividing cells. Somatic cells (non-germline
tissue) have 23 pairs of chromosomes (diploid number 46):
one chromosome from each pair is inherited from each
parent. Chromosome pairs 1-22 are called autosomes,
while the 23rd pair are the sex chromosomes, XX in females
and XY in males. In the ovum or sperm (germ cells or
gonadal tissue cells) one set of autosomes and a sex chro-
mosome are present (haploid set), so that, on fertilization,
a diploid set of chromosomes is restored. Thus, males
determine the sex of the offspring.
3. When viewed under the microscope, each chromo-
some has a visible constriction (centromere). The part of
the chromosome above the centromere is usually shorter,
called the short arm or p (from petite); the long arm is
termed a. Each arm of the chromosome is further divided
into bands for easy reference. Thus, 5q21 is the position
of the adenomatous polyposis coli gene on the long arm
of chromosome 5.
4. Mutation is a change in the gene function which
results either in activation (more protein is produced) or,
more often, inactivation of the gene with reduction or loss
of function. Some diseases with a gene component are
sporadic (Greek sporadikos = scattered, from sperein - to
sow); others, on which I shall concentrate, are familial,
that is, characteristic of a family, because the mutation is
passed on to subsequent generations.
5. Single gene disorders account for many defects. A single
base substitution results in sickle cell disease. A single
point mutation results in some forms of p-thalassaemia.
6. Chromosomal disorders. An extra, free-lying chromo-
some 21 accounts for most cases of Down syndrome.
7. Multifactorial diseases are the result of combined
genetic and environmental factors, including some cases
of cleft lip and palate, club foot, long segment
Hirschsprung's disease and hypertrophic pyloric steno-
sis. Combined genetic and environmental factors are
implicated in insulin-dependent diabetes, ankylosing
spondylitis, peptic ulceration and atherosclerosis.
417
GENERAL CONSIDERATIONS
8. Mendelian inheritance (Gregor Mendel, 1822-1884, the
Augustinian monk who studied the inheritance charac-
teristics of peas) refers to the mode of transmission of
genetic information from generation to generation.
Dominant inheritance (autosomal or X-linked) is clinically
expressed when a copy of the mutated gene is inherited
from one parent but not from the other. In recessive in-
heritance the clinical signs of the disease are evident only
when both copies of the gene have the mutation.
9. Proto-oncogenes (Greek protos = first + onkos = bulk,
mass + -gene = born) are normal cellular genes which par-
ticipate in normal proliferation. They may undergo muta-
tion to form oncogenes, which initiate or stimulate neoplasia.
10. Tumour suppressor genes (or antioncogenes) have the
opposite function.
11. Family history is essential for establishing the diag-
nosis of genetic disorders. The drawing of a family tree
(pedigree - French pied-de-grue = crane's foot, possibly
from the arrowhead on the scroll) is straightforward and
shows in graphic form the mode of genetic transmission
(Fig. 40.1). When a complex of symptoms and signs occur
together in a particular disorder, this is referred to as a syn-
drome, usually named after the authors of the first report,
for example, in 1 969, the Li-Fraumeni syndrome - the cri-
teria for inclusion being an autosomal dominant cancer
predisposition, a wide variety of cancer types, young onset
and a potential for multiple primary sites. An important
surgical familial condition is hereditary non-polyposis
colon cancer, often referred to by the acronym HNPCC.
PREOPERATIVE ASSESSMENT AND
PERIOPERATIVE MANAGEMENT
Key points
• Concentrate on the genetic disorders with
which you, as a trainee surgeon, should be
BC
1:1
Dx58y
BC
BC
H:2
ll:3
Dx 55y
BC
BC
6
M:4
Dx 45y
6
m
llhl
:3
:5
:5
64y
40y
Dx30y
bilateral
Dx33y
bilateral
35y
Dx35y
Fig. 40.1 A family tree for establishing a diagnosis of a genetic disorder. Roman numerals l-lll refer to generations;
arabic numerals refer to the individual (e.g. Ill: S, fifth individual from the third generation shown on the pedigree).
(O) female; (Q) male; shaded symbols = affected; crossed symbols = dead; BC, breast cancer; OV, ovarian cancer;
Dx, diagnosed; y, years (present age or age at diagnosis).
418
GENETIC ASPECTS OF SURGERY
40
familiar, because they may result in serious
complications during surgery and anaesthesia.
• These genetic disorders can be divided into
four groups: defects of haemoglobin and
haemostasis; defects of muscle; connective
tissue defects; and skeletal dysplasias.
Haemoglobin and haemostasis
1. Enquire about history of anaemia, bleeding ten-
dency or recurrent venous thrombosis in the patient or
relatives. The development of sickle cell crisis due to
hypoxia during surgery and the need for factor VIII infu-
sion in haemophilia A are well known. If you obtain a
suggestive history, most rare defects of other clotting
factors can be diagnosed on routine screening. For
example, in Noonan syndrome, with a birth frequency of
1 :2000, factor XI and XII deficiency and thrombocytopenia
occur in 60% of patients. The clinical signs include short
stature, neck webbing, congenital heart defects and
usually subnormal intelligence. There is no chromosomal
abnormality and both sexes are affected.
2. Patients with thromboembolic disease due to in-
herited protein C or S deficiency may give a history of
superficial and deep vein thrombosis, thrombosis of the
mesenteric, cerebral, renal and axillary veins and portal
veins, and pulmonary embolism.
Muscle defects
1 . Malignant hyperthermia is the most serious genetic
disorder of muscle presenting in the operating theatre. It
is estimated to affect approximately 1:15000 paediatric
patients and 1:40 000 adult patients. It is triggered by halo-
genated anaesthetic agents, with or without depolarizing
muscle relaxants. The inheritance is autosomal dominant
or recessive and approximately 50% of families have a
mutation in the calcium ion channel gene on chromosome
19. The patient develops an acute onset of skeletal muscle
rigidity, metabolic acidosis and malignant hyperpyrexia.
Immediately reverse it, or it can lead to tissue damage and
death- The mainstay of treatment is dantrolene, which acts
directly to relax skeletal muscle. Administer 1 mg kg" 1 by
rapid intravenous injection, repeated up to a cumulative
maximum of 10 mg kg -1 , either prophylactically or imme-
diately you suspect a hyperthermic episode.
2. Hand-grip weakness and difficulty in walking are
symptoms of myotonic dystrophy. There is usually a posi-
tive family history. Myotonic dystrophy affects approxi-
mately 1:10 000 individuals and the clinical expression is
very variable. Myotonic dystrophy and the other less
common myotonias are due to defects in the chloride and
sodium channels of the muscle membrane. Patients show
undue sensitivity to various anaesthetics and sedative
agents, including opioids, barbiturates and benzodi-
azepines. Tonic spasms during operation, prolonged recov-
ery from anaesthetic and depression of the respiratory
centre necessitating prolonged ventilation have been
reported. Cold and shivering also induces myotonia.
Myotonic dystrophy usually presents between the ages of
15 and 35 years. The most noticeable clinical signs are facial
and neck weakness with ptosis. Patients usually notice
weakness of hand grip, inability to open the clenched fist
and difficulty in walking due to weakness of foot dorsi-
flexion. This is a multisystem disorder: heart block fre-
quently develops in adults. Fully evaluate these patients
prior to operation. Because anaesthetic management may
be difficult, prefer regional anaesthesia whenever possible.
Connective tissue defects
1 . Is there evidence of poor wound healing, paper thin
scar tissue, joint dislocations and possible aortic aneurysm
in relatives? Connective tissue abnormalities may cause
difficulty during suturing, resulting in a high incidence of
anastomotic and wound dehiscence. In Marfan' s syn-
drome, named for the Parisian paediatrician (1858-1942),
the clinical signs are usually obvious: the patient is tall,
thin, with long slim fingers, chest deformity, scoliosis and
dislocated optic lens. Preoperative cardiac assessment is
mandatory, as there is a high incidence of dissecting aortic
aneurysm with aortic valve insufficiency at a young age.
2. Ehlers-Danlos syndrome was described in 1901 by
the Danish physician Ehlers, and by Danlos a Parisian
dermatologist in 1908. The arterial type IV, in particular,
is characterized by friable arteries and veins, and sponta-
neous arterial rupture has been reported. Paper thin scars,
joint dislocation and spontaneous colonic perforation
may also occur. Arteriography and vascular surgery is
particularly hazardous; if varicose vein surgery is
absolutely necessary, perform it with the utmost care.
Skeletal dysplasias
1. Patients with such disorders may have odontoid
dysplasia or C1-C2 subluxation due to ligamentous
laxity. The patient is of short stature, with some body dis-
proportion. The most commonly encountered conditions
are achondroplasia and Down syndrome, described in
1866 by John Langdon-Down of the London Hospital,
which are easily recognized.
2. Skeletal dysplasia due to mucopolysaccharidosis, an
inborn metabolic storage disorder (such as Hurler syn-
drome), is characterized by a 'coarse' looking face and
mental retardation. Take care to limit head and neck
manipulation during surgical operations for fear of
causing cervical medullary compression. In certain cases,
elective cervical vertebral fusion may be required.
419
40 *
GENERAL CONSIDERATIONS
3. Congenital malformations and genetic disorders
may indicate the presence of unsuspected anatomical
abnormalities of obvious importance to the surgeon.
Patients with Sturge-Weber syndrome have a port wine
stain on the skin, which, if present over the face or
cranium, is associated with epilepsy or mental retarda-
tion. Multiple arteriovenous malformations may be
encountered during surgical manipulation of tissues
beneath the port wine stain.
GENETIC MECHANISM OF CANCER
DEVELOPMENT
Table 40,1 Features which increase the probability
of the presence of genetic predisposition to cancer
• The development of specific (e.g. breast/ovary)
or uncommon (e,g. adrenal/rhabdomyosarcoma)
tumours
• Unusually early onset of cancer (<45 years)
■ Multiple primary cancers in one individual
• Relatives with cancer (maternal or paternal side)
• Associated phenotypic or developmental
abnormalities (rare)
Cancer development is the result of the accumulation of
mutations in a number of genes (4-5 in colorectal
cancer) over time in somatic tissues. Each mutation
results in stepwise clonal proliferation of cells, with the
next mutation giving rise to further expansion. The
mutations are present in two types of genes which
regulate cell growth. There is a mutational activation of
oncogenes and mutational inactivation of tumour sup-
pressor genes (see Ch. 26). A genetic model for colorec-
tal tumorigenesis has been particularly well studied, for
example by Fearon & Vogelstein (1990). Early mutations
in the bowel epithelium in the oncogene ras and the
tumour suppressor genes on 5q and 18q give rise to a
colon adenoma. Additional mutation of the tumour sup-
pressor gene p53 (localized at 17p) result in progression
to carcinoma. Further tumour growth results from the
accumulated loss of suppressor genes on additional
chromosomes. This correlates with the ability of the
carcinomas to metastasize and cause death.
GENETIC SUSCEPTIBILITY TO CANCER
Key points
• Most malignant tumours are sporadic (in one
individual in the family) and develop in older
age.
• Cancer occurring in successive generations in a
family is rare.
1 . Features which suggest the probability of the pres-
ence of a genetic predisposition to cancer are shown in
Table 40.1. As molecular genetic analysis methods have
become available, attention has focused over the last
10 years on unusual families where a particular type of
cancer (breast /ovary, colorectal) has developed in many
relatives, over several generations and at a young age.
2. Significantly the tumours are often bilateral or multi-
focal. This clinical presentation could be explained by an
inherited mutation of a tumour suppressor gene (which is
present in all tissues). Subsequent mutations of further
genes frequently result in multiple tumours at a young age
of onset. This mechanism of genetic susceptibility to cancer
was initially proposed by Knudson in 1986 (Knudson
hypothesis) and has recently been confirmed. Among the
first genes to be localized were those causing clinically
well-characterized disorders such as familial retinoblas-
toma, Wilms' tumour and adenomatous polyposis coli
(APC). Table 40.2 shows the gene localization and clinical
presentation of some of the more common cancer suscep-
tibility genetic disorders. Adenomatous polyposis coli is
an important surgical example of an autosomal dominant
disorder presenting in late childhood /early teens, with
abdominal pain or bleeding per rectum due to multiple
large bowel polyps. At colonoscopy numerous polyps are
visible, almost replacing the bowel mucosa. Polyps may be
present in the rest of the gastrointestinal tract. There is a
high frequency of progression of such polyps to the
adenoma-carcinoma sequence. Another serious complica-
tion in approximately 10% of patients with APC is the
development of desmoid (Greek desmos = chain, bundle +
eidos = like) tumours arising mainly from the peritoneum
or abdominal wall; these are highly vascular and difficult
to resect in their entirety. When you make the clinical diag-
nosis of APC, you must inform the patient's close relatives
and counsel them about their increased cancer risk. They
need to decide whether to have regular colonoscopy, as
some gene carriers develop the polyps later, or opt for a
predictive genetic test or CHIRPE (congenital hypertrophy
of retinal pigment assessment).
420
GENETIC ASPECTS OF SURGERY
40
Table 40.2 Gene localization and clinical
presentation of disorders with a genetic susceptibility to cancer
Disorder
Mode of inheritance
Gene localization
Tumour susceptibility
Retinoblastoma
Autosomal dominant
T3qU
Retinoblastoma,
osteogenic sarcoma
Wilms' tumour
Autosomal dominant
11p13
Nephroblastoma
Adenomatous polyposis coli
Autosomal dominant
5q21
Colorectal,
gastrointestinal tract
Li-Fraumeni syndrome
Autosomal dominant
17p12
Rhabdomyosarcoma,
leukaemia, glioma,
breast cancer
Breast and ovarian cancer
Autosomal dominant
SRCA1-
17q2l
Breast and ovarian
BRCA2-
-13q12
Breast? Pancreas
Hereditary non-polyposis colon cancer
Autosomal dominant
HMSH2
-2p12
Colorectal and
KMLH1
-3p21
gastrointestinal,
hPMS1-
-2q31
ureteric, endometrial,
hPMS-7p22
ovarian cancer
Neurofibromatosis 1
Autosomal dominant
17q11
Benign schwannoma,
brain tumours (rare)
Neurofibromatosis 2
Autosomal dominant
22q13
Optic neuroma,
acoustic neuroma,
meningioma, glioma
von Hippel-Lindau syndrome
Autosomal dominant
3p25
Meningioma, renal
Peutz-Jeghers syndrome
Autosomal dominant
19p
Hamartoma,
gastrointestinal tract
Key point
• Predictive tests for adenomatous polyposis coli
may carry a social stigma or be potentially
misused by insurance and employment agencies.
At the same time, for the patients and their families, the
knowledge of cancer risk and subsequent need for major
surgery is stressful. Mutation analysis in the APC gene
must be performed on a sample from the affected family
member, as many different mutations from different fam-
ilies may be found spanning the whole length of the gene.
When the mutation is identified in a family, prenatal
diagnosis is of course also possible, with all its associated
problems regarding the decision to terminate pregnancy
for late-onset disorder.
3. The cloning of breast /ovarian cancer susceptibility
genes (BRCA1 and BRCA2) has been accomplished (Miki
et al 1994, Wooster et al 1995). This constitutes a major
advance in the study of these common cancers.
Mutations have been identified in all areas of these large
genes. For practical clinical application, less expensive
and less laborious methods of gene analysis need to be
developed.
4. Genetic susceptibility to breast and ovarian cancer is
impossible to diagnose clinically in the absence of a con-
vincing pedigree suggestive of autosomal dominant
inheritance. Several mutations occur more frequently in
the Ashkenazi Jewish population; the knowledge of the
patient's background may facilitate mutation detection.
The population risk for breast cancer in a woman aged
30-39 is 4 in 1000. While the numbers of cases analysed to
date are relatively small, and with only preliminary data
available, the percentage of breast cancer due to BRCA1
within that age range has been estimated at 5%.
5. A number of cancer syndromes have been
described, showing a characteristic combination of
cancers (Table 40.2). As relatively small numbers of fam-
ilies have been analysed to date; it is likely that a more
accurate clinical spectrum will be available in the future.
6. The study of families with a high frequency of site-
specific colorectal cancer and colorectal cancer associated
with malignant tumours of the genitourinary tract, uterus,
breast cancer and other malignancies has facilitated the
recent discovery of several new genes. These syndromes
421
GENERAL CONSIDERATIONS
were initially described by Lynch et al (1988), but have sub-
sequently been termed liereditary non-polyposis colon
cancer' and 'cancer family syndrome'. The colorectal cancer
is of early onset with a proclivity to the proximal colon and
an excess of synchronous (Greek syn = together + chronos -
time, hence simultaneous) /metachronous (Greek meta =
after; hence occurring in sequence but separated by inter-
vals) lesions. It is often, but not always, preceded by the
development of colonic polyps. Colonoscopy is advocated
every 3-5 years, with an increasing frequency in the pres-
ence of polyps. The surveillance for the associated cancers
is problematic because, again, clinical diagnosis is difficult.
Genetic diagnosis is now possible, but methodological
problems will need to be overcome for potential clinical
application, as is the case with BRCA1/2 genes.
7. It has been noted that tumours from these affected
individuals contain a large number of DNA replication
errors. The normal function of these newly discovered
genes is to survey the fidelity of DNA replication and
repair. Mistakes are frequently introduced during normal
DNA replication and DNA repair has to take place, espe-
cially when the cell is exposed to carcinogens, ionizing
radiation or alkylating agents. The clinical expression of
mutations in these genes is compatible with their function
as tumour suppressor genes. The frequency of these gene
mutations in the population is unknown, but in patients
with colorectal cancer, genetic susceptibility has been
estimated to account for 5-10% of cases.
8. Advances in molecular genetics continue at an intense
pace. With the current study of oncogene amplification to
tumour stage and ultimately to prognosis, and the further
development of tumour drug targeting and gene therapy,
major practical advances in cancer prediction, detection
and therapy should be forthcoming in the foreseeable
future. Exciting recent developments include predictive
genetic testing for relatives at high risk for developing
cancer by mutation analysis. Clinical trials directed
towards early cancer detection and chemoprevention in
this group will provide statistically significant outcome
data in a shorter time than other general population trials.
Summary
• Can you identify the genetic disorders that
may predispose to life-threatening
complications during surgery or
anaesthesia?
• Which congenital defects in
haemoglobin, haemostasis, muscle,
connective tissue and the skeleton should
you note?
• Do you understand the accumulation of
mutations in oncogenes and in tumour
suppressor genes that may increase
susceptibility to cancer?
• Do you realize that genetic mutations in
specific tumour suppressor genes were
identified in approximately 20% of
individuals with early onset and family
history of cancer?
• While the great majority of cancers are
sporadic, what salient features in the
history and examination suggest a genetic
increased susceptibility to cancer?
References
Fearon ER, Vogelstein B 1990 A genetic model for colorectal
tumorigenesis. Cell 61: 759-767
Lynch HT, Lanspa SJ, Bonan BM 7 Smyth T, Walson P, Lynch JF
1988 Hereditary non-polyposis colorectal cancer, Lynch
syndromes I and II. Gastroenterology Clinics of North
America 174: 679-715
Miki Y, Swensen J, Shattuck-Eidens D et al 1994 A strong
candidate for the breast and ovarian susceptibility gene
BRCA1 . Science 266: 66^-71
Wooster R, Bignell G, Lancaster J et al 1995 Identification, of the
breast cancer susceptibility gene BRCA2. Nature 378(6559):
789-792
422
Screening for surgical disease
T. Bates
*
Objectives
• Identify essentials for justifying a
screening programme.
• Appreciate the practical requirements.
• Recognize the cost-benefits, including
mortality and quality of life.
INTRODUCTION
At first sight, screening the population for the common
forms of surgical disease seems a good idea, as it should
then be possible to cure the condition before it becomes
symptomatic. Cancer of the lung, which is still the com-
monest malignancy, with 22 700 male and 11 000 female
deaths in England and Wales per year (Office of Population
Censuses and Surveys 1994), has such a poor prognosis that
screening the population by mass miniature chest X-ray
failed. In contrast, prevention, by a public health pro-
gramme to stop smoking, has reduced death rates by
almost a third in men. Screening programmes have been set
up for carcinoma of the colon, stomach, breast and cervix,
and more recently the prostate and ovary. It is possible that
screening for non-malignant conditions such as abdominal
aortic aneurysm may reduce the number of deaths in older
men from leaking aneurysm. To be effective, early detection
and treatment must lead to fewer deaths from the disease,
or have a major impact on the quality of life in the screened
population, but in some of these conditions there are still
doubts that this can be achieved.
BIAS
■^^^^■^^^'^^^^^^^^^■^"^^'^y^^ -■■>*"S
Lead time bias
■^;^;-':>>V!^^:^
The term Tead time' originated as the interval between a
decision to begin a process and the completion of the
project. An increased survival time from diagnosis to
death could well be due to earlier, and therefore more
prolonged, observation of the natural history of the
disease, which might be unaffected by the treatment. This
situation is known as lead time bias and in breast screen-
ing is usually reckoned to be about 2 years.
Length bias
1. If the interval between screening episodes is rela-
tively long, the test detects those cases with slowly
growing tumours, whereas rapidly growing cancers with
a worse prognosis tend to present in between screens.
Both lead time and length bias increase the apparent
benefit of screening, without necessarily improving the
natural history of the cancer in question.
2. The acid test for a screening programme is to
compare a screened population with an identical non-
screened population; this is ideally set up as a random-
ized controlled trial (see Ch. 45), to avoid unrecognized
systematic biases (Shapiro 1981, Hardcastle et al 1996). If
the disease carries a relatively good prognosis when ade-
quately treated at an early stage, it may take many years
of observation to show a difference in the number of
deaths between the screened and non-screened groups;
this requires considerable resources.
3. There are many questions which must be answered
before considerable amounts of time, money and effort
are committed to a screening programme. These ques-
tions must be addressed by several disciplines: clinical
scientists in the relevant specialty, epidemiologists with
expertise in screening, social scientists and economists.
4. Is the burden of the disease in the population suffi-
cient to warrant an intervention? Is the screening test
accurate in detecting cases in the population to be
screened, and is the subsequent treatment effective in
curing the disease? In trying to answer these three
critical questions the following specific issues must be
considered.
423
41
GENERAL CONSIDERATIONS
Key points
If longer survival from progressive disease is
claimed to result from improved screening:
• Was the diagnosis being made at an earlier
stage of the disorder than previously?
• Were the patients suffering from a less
rapidly aggressive form of the disease than is
usual?
• Will early detection alter the natural history of
the disease?
To be effective a screening test must
be:
• Sensitive - low false-negative rate
• Specific - low false-positive rate
• Of high negative predictive value - should
effectively rule out the condition
• Safe and acceptable - with a high compliance
rate
• Effective - treatment should reduce the
number of deaths, the severity of treatment
and improve the quality of life.
REQUIREMENTS FOR A SCREENING
TEST
1 . Is the screening test sensitive: does it detect most of
the cases, with few false negatives?
2. Is the test specific: does it detect only cancer cases,
with few false positives?
3. Is the negative predictive value of the test high: does
a negative test provide reassurance that the risk of the
condition is very low?
4. Is the test safe, relatively inexpensive and capable of
achieving adequate compliance in the population to be
screened?
There are many examples of screening where these
criteria have not been met. O-tolidine-based dyes for
detecting occult blood increased the risk of bladder
cancer in laboratory staff. The dose of irradiation initially
used for breast screening mammograms is no longer
regarded as safe. Investigation and treatment of false-
positive cases may lead to psychological or physical
morbidity. A few cases, only, of suicide precipitated by
the anxiety of a positive or doubtful test negate or at
least undermine any real survival advantage from early
diagnosis and treatment.
False-negative screening tests, or clerical failure to
notify people of positive results, cause a public outcry
when a delay in diagnosis has led to the need for more
radical treatment or even a premature or preventable
death. Such failures have tended to undermine public
confidence in the cervical and breast screening pro-
grammes in the UK. Sensitivity and specificity tend to be
inversely related. The individual performance of screen-
ing radiologists is monitored; a radiologist in the breast
screening programme with a high sensitivity has a
high recall rate with more false-positive cases, and there-
fore a low specificity; and vice versa (Grimes & Schulz
2002).
POPUL^ON^T
The at-risk population must be defined. To screen young
people for cancer does not make sense but cancer of the
cervix has become more common in younger women; this
has led to a lowering in the age at which screening is
offered. It is essential to have an accurate register of the
population to be screened, and in city areas this must be
frequently updated if the clients are to receive invitations
for screening. Screening the elderly is likely to show poor
uptake (compliance) with age, and an increasing propor-
tion of patients will die of intercurrent disease. The
cost:benefit ratio is therefore less favourable but there may
be political resistance to the omission of this age group.
Screening of high risk groups, such as those with a
strong family history of cancer, poses special problems
and different criteria must be used.
COLORECTAL CANCER
Colonoscopy is the 'gold standard' test (against which
other tests are measured) for detecting colonic cancer or
polyps. It has both specificity and sensitivity nearing 100%,
but high cost and low compliance rule this out as a screen-
ing test except for those at very high risk from, for example,
familial adenomatous polyposis, or longstanding ulcer-
ative colitis. Those at risk from colorectal cancer should be
ideal candidates for screening, as many cancers are pre-
ceded by benign adenomatous polyps. Furthermore, early
cancer (Dukes' stage A) has a 5 year survival of 90% with
conventional operative treatment. However, the best avail-
able test is poor. The guaiac-based Haemoccult test of three
samples is probably the best available test for faecal occult
blood but it has a relatively low sensitivity, especially for
right-sided and rectal tumours. Immunologically based
tests are more sensitive but less specific and give rise to
false-positive cases which require expensive and unneces-
sary investigation.
424
SCREENING FOR SURGICAL DISEASE
41
Randomized controlled trials of faecal occult blood
screening have shown a reduced number of deaths from
colorectal cancer by 15-33% in the screened group
(Hardcastle et al 1996, Kronborg et al 1996). It is intended
to introduce systematic screening in the UK. The issues
are well reviewed by Ransohoff & Sandler (2002).
CANCER OF THE BREAST
There have been four randomly allocated trials of popu-
lation screening for breast cancer by mammography; of
these, only the Swedish two-counties study has shown
a significant reduction in mortality (Tabar et al 1989).
However, an overview of these trials and other non-
randomized studies shows that all report fewer deaths in
the screened versus the non-screened population (Wald et
al 1991). There has been a recent reduction in the number
of deaths from breast cancer in many countries (Peto et al
2000) but the trend preceded screening and may be
principally related to the increased use of adjuvant
therapy (Latin adjuvere = to aid; something that enhances
the effectiveness of medical treatment).
CARCINOMA OF THE CERVIX
Key point
• The incidence of cancer varies over time for
many reasons. Do not automatically assume
that screening programmes have generated
observed improvements.
There has been an unexpectedly high number of
cancers presenting between 3-yearly screens (interval
cancers) in the UK National Breast Screening Programme,
which has led to the adoption of two-view instead of
single-view mammography for the first screen (Blanks
et al 1997), but a randomized trial of 2 versus 3 years
showed no benefit from an increased frequency of screen-
ing (UKCCCR 2002). The upper age limit will be
increased from 64 to 69 years in the UK, as compliance in
this age group seems better than was expected and there
is evidence of benefit. Screening women under the age of
50 achieves a relatively small reduction in the number of
deaths and remains controversial. Recent criticism of the
methodology used in the randomized trials of breast
screening (Olson & Gotzsche 2001) has been countered by
an updated overview of the Swedish randomized trials
(Gelmon & Olivotto 2002, Nystrom et al 2002). This shows
a 21% reduction in breast cancer deaths but the age-
adjusted relative risk for total mortality was 0.98
(0.96-1.00).
Unfortunately no randomized trial of cytological screen-
ing for carcinoma of the cervix has been carried out.
Although death rates for this disease have fallen in many
countries, this fall has often preceded the introduction of
screening (Williams 1992).
Up to 60% of women who have developed cervical
cancer in the UK had never been screened, and the false-
negative rate for examination of the smears is about 10%.
Not all smears are adequate, and cytoscreening is very
labour intensive and susceptible to problems with quality
control (Miller 2002). This is unsatisfactory because ade-
quate treatment of cervical intraepithelial neoplasia (CIN)
is highly successful. An efficient mechanism has been
developed for recalling and treating patients with posi-
tive smears based on general practice, and compliance
has reached 83% (Austoker 1994a).
The incidence of cancer of the stomach seems to be falling
as colon cancer rises but these changes may be con-
founded (an alternative explanation for the observed
facts) by the vagaries of death certification.
Cancer of the stomach is much more common in Japan,
where screening for early gastric cancer seems to be effec-
tive (Hisamichi & Sugawara 1984) with the use of barium
studies, gastroscopy and, more recently, serum pepsino-
gen. In the UK the search has been less successful. It is
suggested that screening by gastroscopy should be
confined to symptomatic patients over the age of 55
(Hallissey et al 1990).
Q^RaNOMAOF™
Screening for carcinoma of the prostate is controversial, as
the disease mainly affects an elderly population and 30% of
men over the age of 50 have histological evidence of pro-
static cancer at necropsy but in only 1% of these is there
clinically active disease (Austoker 1994b). The available
screening tests, apart from rectal examination, are prostatic-
specific antigen and transrectal ultrasound. Neither the sen-
sitivity nor the specificity of these tests is high, either alone
or in combination, and the treatment of localized prostatic
cancer is also controversial. Radical prostatectomy, radio-
therapy, hormonal manipulation and a watch policy are all
used but there is as yet no randomized trial that is suffi-
ciently mature to indicate survival benefit. It is important
not to cause unnecessary morbidity in elderly men with
asymptomatic disease (Donovan et al 2001).
425
41 ''
GENERAL CONSIDERATIONS
CANCER OF THE OVARY
Evidence for survival benefit from screening for carci-
noma of the ovary is lacking but a large randomized con-
trolled trial has been organized. The main screening tests
are antigen marker CA 125 and transvaginal ultrasound,
but other tumour markers and colour Doppler are being
evaluated. The sensitivity of CA 125 for early ovarian
cancer may be as low as 50%. There is, however, a strong
case for screening a high risk group with familial ovarian
cancer syndrome (Austoker 1994c).
SCREENING FOR NON-MALIGNANT
SURG^
Neonatal screening
Congenital disease is increasingly diagnosed as a result
of routine antenatal ultrasound screening but postnatal
clinical examination must be carried out to exclude
congenital cardiac and renal abnormalities as well as
orthopaedic, sexual and anorectal malformations. Most
congenital abnormalities usually present as a clinical
problem in the first few days of life. Recognize also silent
conditions, such as congenital dislocation of the hip, in
which delayed diagnosis may worsen the outcome.
Abdominal aortic aneurysm
This accounts for 2900 male and 1040 female deaths per
year in England and Wales.
There are several population screening studies from
the UK and the USA, and in men over the age of 65 ultra-
sound screening of the aorta shows a prevalence (the
percentage of population affected, as opposed to
incidence, which is the rate of occurrence) of aneurysm
of about 5%, depending on size criteria. This rate may be
twice as high in men with hypertension or vascular
disease, and the lifetime prevalence in first-degree male
relatives may be as high as 50% (Collin 1994). Deaths
from leaking abdominal aortic aneurysm can be reduced
by screening men at age 65 years, combined with a
policy of electively operating on fit patients with an
aortic diameter of about 5.5 cm or more. (Multicentre
Aneurysm Screening Study 2002).
WHAT COMPLIANCE IS TO BE
EXPECTED?
screening test and the perceived effectiveness of the
treatment. Screening for breast cancer by mammography
achieves 80% in areas with a stable population but may
be less than 50% in inner city areas. Compliance is also
sensitive to media exposure in the short term.
In screening for colorectal cancer, the acceptability of
the faecal occult blood test is very low, leading to poor
compliance; unless public awareness is increased at the
time that screening is offered. There are many reasons
why people decline screening invitations but failure to
receive the letter is a common cause. The true refusers are
an unusual group of people who have a poor outlook
from both a health and a social standpoint. They neglect
or abuse their health in many respects and cannot there-
fore be used as a control group for comparison with those
who accept screening; whatever comparison is made, the
refusers will be disadvantaged. Compliance for cervical
screening is worst in the low socioeconomic group most
at risk from the disease (Segnan 1997).
THE INTERVENTION TO BE USED
&^^^^ft>^j'^fefefe^^^^
^i^i^y^^.^-^
:^^s3fr^^
Compliance, conforming to the advice of the screeners,
varies with the social acceptability and public awareness
of the disease, the inconvenience or discomfort of the
It has already been noted that an operation for early
bowel cancer has a high cure rate but we cannot be sure
that this is the case for breast cancer. Screen-detected
breast cancer has many features known to indicate a good
prognosis (Klemi et al 1992) but ductal carcinoma in situ
is diagnosed in up to 20% of screened cases and the best
treatment for this condition is still in doubt. It is possible
that fear of overtreatment by mastectomy may lead to a
sacrifice of survival advantage by inadequate surgery.
Severe dysplasia of the cervix (CIN III) has an extremely
good outlook with local treatment and close surveillance.
Node-positive carcinoma of the stomach has a 5 year sur-
vival rate of less than 10% but in situ tumours carry a
good prognosis with adequate surgical treatment. The
Japanese have pioneered surgery for gastric cancer that is
more radical than has been the norm in the West; clinical
trials are currently in hand to try and repeat their excel-
lent results in the UK. The place of radical prostatectomy
in the treatment of screening-detected prostatic cancer
remains uncertain.
Abuse of screening
Opportunistic screening may be offered or even adver-
tised to give "peace of mind' where there is no evidence
of benefit. High technology tests, such as electron-beam
computed tomography (CT) for detecting obstructive
coronary artery disease and low dose spiral CT for detect-
ing early lung cancer, have been criticized in this respect,
and it seems likely whole body CT scans will be the next
high technology test (Lee & Brennan 2002).
426
SCREENING FOR SURGICAL DISEASE
41
o—
Key points
Controversies in screening
• False negative tests cause public concern and
fear of litigation, especially in carcinoma of the
cervix and carcinoma of the breast.
• There is doubt as to the actual reduction in the
number of deaths.
• False-positive tests lead to unnecessary
investigations/operations.
• The high cost of screening might be better
spent elsewhere.
WHAT IS THE COST?
i:^^ ; 5^^Sv^^S : : &&^£1S + >v^>&^^ ii
"^-^?££ftiW^^^
Economists wish to know the cost per case detected, per
case treated and per life saved. Sociologists wish to know
the psychosocial cost in those false-positive cases investi-
gated unnecessarily and the quality of life in those
patients who have cancer detected sooner than it other-
wise would have been.
Summary
• How do you decide whether or not a
screening test for cancer is capable of
detecting disease at a stage when earlier
treatment will lead to fewer deaths?
• What are the sensitivity and specificity of a
test, and how can your assess them?
• What is meant by 'high negative predictive
value'?
• Why does the treatment of a screened
disease need to be effective?
• How do cost and quality of life enter into
consideration?
References
Ashton HA, Buxton MJ, Day NE et al 2002 The Multicentre
Aneurysm Screening Study (MASS) into the effect of
abdominal aortic aneurysm screening on mortality in men: a
randomised control trial. Lancet 360: 1531-1539
Austoker J 1994a Screening and self-examination for breast
cancer. BMJ 309: 168-174
Austoker J 1994b Screening for cervical cancer. BMJ 309:
241-248
Austoker J 1994c Screening for ovarian, prostatic and testicular
cancers. BMJ 309: 315-320
Blanks RG, Moss SM, Wallis MG 1997 Use of two view
mammography compared with one view in the detection of
small invasive cancers: further results from the NHS breast
screening programme. Journal of Medical Screening 4: 98-101
Collin R 1994 Abdoiriinal aorta: epidemiology. In: Morris PJ,
Malt RA (eds) Oxford textbook for surgery. Oxford University
Press, New York, pp 377-378
Donovan JL, Frankel SJ, Neal DE, Hamdy FC 2001 Screening for
prostate cancer in the UK. BMJ 323: 763-764
Gelmon KA, Olivotto I 2002 The mammographic screening
debate: time to move on. Lancet 359: 904 — 905
Grimes DA, Schulz KF 2002 Uses and abuses of screening tests.
Lancet 359: 881-884
Hallissey MT, Allum WH, Jewkes A], Ellis DJ, Fielding JWL
1990 Early detection of gastric cancer. BMJ 301: 513-515
Hardcastle JD, Chamberlain O, Robinson MH et al 1996
Randomised controlled trial of faecal occult blood screening
for colorectal cancer. Lancet 348: 1472-1477
Hisamichi S, Sugawara N 1 984 Mass screening for gastric
cancer by X-ray examination. Japanese Journal of Clinical
Oncology 14: 211-223
Klemi PJ, Joensuu H, Tbikkanen S et al 1992 Aggressiveness of
breast cancers found with and without screening. BMJ 304:
467-^69
Kronborg O, Fenger C, Olsen J et al 1996 Randomised
controlled study of screening for colorectal cancer with faecal
occult blood test. Lancet 3348: 1467-1471
Lee TH, Brennan TA 2002 Direct to consumer marketing of
high-technology screening tests. New England Journal of
Medicine 346: 529-531
Miller AB 2002 The (in)efficiency of cervical screening in
Europe. European Journal of Cancer 38: 321-326
Nystrom L, Anderson I, Bjurstam N, Frisell J, Nordenskjold B,
Rutgvist LA 2002 Longterm effect of mammographic
screening: updated overview of the Swedish randomised
trials. Lancet 359: 909-919
Office of Population Censuses and Surveys 1994 Series DH2,
No. 19. Mortality statistics for 1992. Cause. HMSO, London
Olson O, Gotzsche PC 2001 Cochrane review on screening for
breast cancer with mammography. Lancet 358: 1340-1342
Peto R, Boreham J, Clarke M, Davies C, Beral V 2000 UK and
USA breast cancer deaths down by 25% in year 2000 at ages
20-69 years. Lancet 355: 1822
Ransohoff DF, Sandler RS 2002 Screening for colorectal cancer.
New England Journal of Medicine 346: 40-44
Segnan N 1997 Socioeconomic status and cancer screening.
I ARC Scientific Publications 138: 369-376
Shapiro S 1981 Evidence on screening for breast cancer from a
randomised trial. Cancer 39: 618-627
Tabar L, Fagerberg F, Duffy SW, Day NE 1989 The Swedish two
counties trial of mammographic screening for breast cancer:
recent results and calculation of benefit. Journal of
Epidemiology and Community Health 43: 107-114
United Kingdom Co-ordinating Committee on Cancer Research
2002 The frequency of breast screening: results from the
UKCCCR randomised trial. European Journal of Cancer 38:
1458-1464
Wald N, Frost C, Cuckle H 1991 Breast cancer screening: the
current position. BMJ 302: 845-846
Williams C 1992 Ovarian and cervical cancer. BMJ 304:
1501-1504
427
Audit
fl, Davidson, H. J. Schneider
Objectives
Appreciate what audit is and its vital link
with clinical effectiveness.
Recognize that audit is but the first step,
not an end in itself.
Recognize the need to change clinical
practice in the light of audit findings.
Use audit as a valuable educational tool.
INTR^
Audit (Latin auditus - a hearing) is a critical appraisal of
the care dispensed by clinicians. There have been many
examples of audit activity in a number of guises over the
last few centuries. One of the most notable surgeons to
declare his failures as well as successes for the benefit of
colleagues was the great 19th century German surgeon of
Swedish origin, Theodor Billroth (1881).
The improvement in standards of care in surgery as a
whole and in the practices of individual surgeons has,
until recently relied on the apprenticeship of the training
years, and the dissemination of new learning and good
practice through the medium of the book, the journal and
the lecture by the 'expert'. Those who were prepared to
listen and read were able to change practice where appro-
priate. Even now, many surgeons rely on the annual meet-
ings of the various 'craft' associations for education in
current surgical practice.
The roots of modern audit lie in the regular morbidity
and mortality meetings held in many hospitals in the
USA. The value of these meetings as a means of learning
was recognized and formed the basis of broader audit
activities. When transferred to the British Isles in the
1950s, the American drive for change based on the find-
ings, and the educational importance, were missing.
In the early 1980s, microcomputers became available
and made it possible to collect and analyse large amounts
of information very swiftly. Most of us now have, or
should have, access to reliable, peer-reviewed data on all
aspects of medicine and surgery (see Ch. 12). This pro-
vides us with a powerful tool to assist in the interpreta-
tion of types of work done, throughput, complications,
cost and mortality. We have the opportunity to see what
are the best results, compare ours with them, determine
the reason for differences and react to them.
Possession of an audit system is not synonymous with
the successful practice of audit. Systems are merely tools
with which we can get a grasp and some understanding
of the activity for which we are responsible. Moreover,
there is great variation in acquisition, recording,
analysing and using information. For this reason some
people deprecate attempts to collect and compare it -
but imperfect information is better than none at all. A
danger of having easy access to information is that it is
collected but never utilized. Unless it is applied in an
effort to produce improvements, it is merely bureau-
cratic detritus.
Every hospital in the UK is now responsible for ensur-
ing the development of clinical audit in which all
doctors participate. The requirement for audit is now
written into the job descriptions for all new medical
staff. However, effectiveness in securing worthwhile and
lasting improvements in the quality of care for patients
is still very variable (Walshe & Spurgeon 1997). These
authors have developed a clinical audit assessment and
improvement framework designed to improve the effec-
tiveness of audit programmes and individual audit
projects.
Until 1990 there was no funding or allocation of time
for audit activity. Health authorities must now agree
plans for audit, addressing local service and clinical prior-
ities with trust managers and audit groups. As part of the
audit contract with hospitals, health authorities can
request audit of specific clinical areas.
DEF|NITIOIK,______
Clinical audit is defined by the Department of Health as:
'The systematic, critical analysis of the quality of medical
care, including the procedures used for diagnosis and
428
AUDIT
treatment, the use of resources, and the resulting outcome
and quality of life for the patient', and states that 'an
effective programme of medical audit will also help to
provide reassurance to doctors, their patients, and man-
agers that the best quality of service is being achieved,
having regard to the resources available' (Department of
Health 1989). The efficient and effective use of resources
is important (Ellis et al 1990), but it is not the first prior-
ity of clinical audit.
improvement and to provide a mechanism for bringing
them about. As such, it endeavours to get away from the
'single interesting case' and look for patterns of care that
should ideally be evaluated against research-based
evidence or accepted best practice. Audit should initiate
investigation into those areas of clinical care that are con-
sidered as high risk, high cost or very common. Audit
investigation is also suitable for resolving issues of con-
tention or local interest.
Key points
• Omitted from the Department of Health's
definition is the vital educational component
for you as a trainee surgeon.
• Clinical audit is not only a critical assessment of
what has and has not been done but a
potentially powerful and practical teaching aid.
Clinical audit is the responsibility of clinicians and must
be led by us. The terms 'clinical audit' and 'medical audit'
are sometimes used interchangeably, but a consensus has
developed whereby medical audit refers to the assessment
by peer review of the medical care provided by the
medical profession to the patient, and clinical audit refers
to an assessment of the total care of the patient by nurses,
professions allied to medicine (such as physiotherapists)
as well as doctors. The multiprofessional team has an
essential role in patient care and the quality of health care
cannot be determined by doctors alone. Most hospitals
have now focused their audit activity around clinical
rather than medical audit.
A revised position statement on clinical audit identifies
future goals:
• Clear patient focus
• Multiprofessional working
• Patient care managed across primary, secondary and
continuing care
• Closer links with education
• Integration of effectiveness information
• Improvement of clinical effectiveness.
ATTrrilDE S TO AU DIT
1. You may argue that audit is practised already; that
ward rounds, clinical presentations, research and mor-
bidity and mortality meetings fulfil this function.
However, there are differences between these and clinical
audit. Audit must be seen as a systematic approach to the
review of clinical care to highlight opportunities for
P 5 !
I I Key point
• Discussing the rare and clinically interesting
case is not audit. Leave it for the clinical
conference.
2. You may feel that the time spent on audit could be
much better spent on other activities, such as treating
more patients. This is not a wholly spurious argument;
audit was introduced without any prior evaluation and,
although there have been several subsequent evaluations,
the results have, to date, failed to demonstrate clear value
for money or effort expended (Walshe 1995).
3. There is, none the less, general agreement that a
regular review of your own practice against agreed stan-
dards of best practice can lead to improved care of
patients, who must be the principal beneficiaries of the
process.
4. Clinical audit improves patient care not only
through direct changes in clinical practice but also
through indirect effects such as professional education
and team development.
5. An effective clinical audit programme can give the
necessary reassurance to patients, clinicians and man-
agers that an agreed quality of service is being given
within available resources.
6. Clinicians and managers share audit information
within agreed rules of confidentiality. Many deficiencies
revealed by audit relate to the organization of care and,
although audit must remain clinically led, support from
National Health Service (NHS) board directors and man-
agement is vital if it is to achieve the necessary changes
in practice.
7. There is a growing need to base clinical practice on
the knowledge obtained from rigorous research into the
effectiveness of healthcare interventions.
8. However, your freedom to determine the treatment
you offer individual patients must be preserved - but
remember that you may need to justify it as accepted or
evidence-based practice if there is an adverse outcome.
9. An important part of the national research and
development strategy is to make information on research
429
42
GENERAL CONSIDERATIONS
findings easily available to clinical and managerial staff,
both in printed form, such as Effective Health Care
bulletins, and electronic media, such as the Cochrane
Library.
AUDIT COMMITTEE
UK hospital clinical audit committees draw members
from a range of clinical backgrounds, such as nurses,
general practitioners, educational tutors, trainee doctors,
pharmacists and physiotherapists, together with audit
staff. The committee reports to the unit management. The
chairman needs to be well motivated and prepared to
devote time on a regular basis.
Audit committee functions are to:
1 . Coordinate and foster clinical audit for everyone
involved in patient care
2. Offer reassurance that audit is valuable for patients
and clinicians, not threatening
3. Determine existing practice of audit
4. Assist clinicians to implement audit methods
5. Monitor the data, results, conclusions and reporting
of the audit process
6. When changes are indicated, ensure they are
implemented and the effects monitored
7. Promote the educational value of audit
8. Maintain confidentiality
9. Ensure effective liaison with general practitioners
10. Staff requirements include an audit officer and /or
coordinator to enable the implementation of audit,
and to assist clinicians in the execution of the audit
process. They help plan and prepare audit
programmes, plans and literature searches, and
screen case records against determined criteria.
They give computer assistance with databases,
graphics, forms and help with the preparation of
reports.
The Royal College of Surgeons of England has published
guidance on audit, Clinical Audit in Surgical Practice
(1995), as well as a number of clinical guidelines.
A National Centre for Clinical Audit (NCCA) was
established in 1995. Publications include the NCCA
Clinical Audit Action Pack (1996), a regular newsletter and
a series of fact sheets. The centre runs an information
service and has its own web site on the internet.
METHODS
Donabedian (1966) identified three main elements in the
delivery of health care: structure, process and outcome.
1 . Structure includes the quantity and type of resources
available and is generally easy to measure. It is not a good
indicator of the quality of care but should be taken into
account in the assessment of process and outcome.
2. Process defines what is done to the patient. It
includes consideration of the way an operation was per-
formed, what medications were prescribed, the adequacy
of notes, and compliance with consensus policies. There
is an underlying assumption that the activities under
review have been previously shown to produce an
optimal medical outcome. This is the area of patient care
that is most open to change by clinicians.
3. Outcome is the result of clinical intervention and may
represent the success or failure of process. For example,
outcome could be measured by studies of surgical fatal-
ity rates, incidence of complications, or patient satisfac-
tion. It can be considered to be the most relevant indicator
of patient care, but it is the most difficult to define and
quantify. Mortality and length of stay in hospital are very
easily measured outcome indicators, but variations in
these outcomes are rarely related directly to the quality of
the service being delivered. It may be more important to
consider whether patients perceive that their problems
have been solved, their quality of life improved and,
where appropriate, the duration of their survival.
A number of audit techniques have evolved and found
a place in the regular assessment of clinical practice.
Basic clinical audit entails analysing throughput and
case type, and assessing complications, morbidity and
mortality. A review of such data is undertaken by each
clinical firm at intervals of approximately 3 months. The
essential ingredient is to distil out of the data any notable
deviations from an accepted 'norm' and then to investi-
gate the reason for this observation.
Incident review involves discussing strategies to be
adopted under certain clinical situations. An 'incident'
may be a leaking aortic aneurysm or using a department
for an investigation such as emergency intravenous uro-
graphy. The discussions should lead to clear policies for
future actions and use, with the construction of local
guidelines. This audit method is particularly suitable for
multidisciplinary or interdisciplinary audit.
Clinical record review. A member of another firm of the
same or similar speciality reviews a random selection of
case notes, preferably having been given criteria (Greek
krites - judge; hence, standards) against which to assess
them. Clinical record audit has the advantage of sim-
plicity and requires relatively little additional time or
other resources. However, there is a potential disadvan-
tage in that discussion might concentrate too much on the
quality of record keeping and not enough on patient care
- these two are distinct facets of the clinical process,
although related.
430
AUDIT
Criterion audit is a more advanced and structured form
of incident audit. Retrospective analysis of clinical
records is made and judged against a number of carefully
chosen criteria. These criteria should encapsulate the key
elements in management of a particular topic which are
capable of unambiguous interpretation from the medical
record, by a non-medical audit assistant. All cases falling
within the scope of the topic in question are screened and
those that fail to meet any of the criteria are brought
forward for further clinical review. The criteria may relate
to administrative elements such as waiting time, investi-
gations ordered, treatments given, outcome and follow-
up strategies. Criteria for adequate management of a
particular condition can be derived easily from clinical
guidelines. Clinicians need to participate actively in the
preliminary discussion, but thereafter most of the work
can be performed by audit assistants. The method is
applicable to a variety of circumstances and allows data
to be compared between different hospitals (Shaw 1989).
The criteria can be used for setting standards, with targets
identifying the proportion of patients in whom each cri-
terion should be met. After review, new targets can be set
to stimulate improvement. For example, a suitable target
is the reduction of infection rates in colorectal surgery to
those obtained in other published studies (Hancock
1990).
Adverse occurrence screening is intended to identify
events that need to be avoided, such as wound infections,
unplanned readmissions, delayed or erroneous diag-
noses. Occurrences are recorded and those that are
complex or serious are reviewed by clinicians. A database
is accumulated which can then be interrogated to identify
trends and, for example, perform comparative analyses.
Cases can be considered in total or as samples. This tech-
nique can also be used for risk management (Bennett &
Walshe 1990).
Comparative audit implies the collection of data and its
comparison across units, health authorities and even
through a whole region (Gruer et al 1986, Black
1991). Within a single hospital, comparisons may be dif-
ficult because the number of departments undertaking
similar work is often very small, and the case mix even
between two general surgical firms may be disparate. The
Royal College of Surgeons (1991) set up a comparative
audit service in which all surgeons supply information
under a confidential number for comparison with their
peers at regular meetings. Techniques in data presenta-
tion allow such sensitive information to be widely
disseminated and discussed, while maintaining an indi-
vidual clinician's confidentiality (Emberton et al 1991). In
Scotland, a regional computerized audit system main-
tained by general surgeons over 15 years, recording clini-
cal data which is regularly reviewed in a peer group
setting, has provided clear evidence that regional audit
can significantly influence and improve surgical practice
(Aitken et al 1997).
National studies were first used to study perinatal mor-
tality in obstetric units. The report of the first confiden-
tial enquiry into perioperative deaths (CEPOD: Buck et
al 1987) considered the factors involved in the deaths of
patients who died within 30 days of operation within
three regional health authorities. Much was learned,
especially the need for doctors in the training grades to
be given adequate support and supervision. Disaster
was clearly associated with surgeons attempting proce-
dures for which they possessed insufficient skill or train-
ing. Subsequently a national review (NCEPOD) was
launched; data is submitted on a voluntary, confidential
basis by surgeons and anaesthetists. Reports are pub-
lished annually (Gallimore et al 1997). The findings can
identify remedial actions and indicate appropriate topics
for local audit, such as out-of-hours surgery (Campling
et al 1997).
Outcome audit is a review of the whole process of
healthcare delivery during a patient's hospital contact. It
thus measures all the skills of the medical and nursing
staff, the hospital administration and, indeed, all those
with whom the patient comes into contact. Inevitably
there are different perspectives of outcome by the patient,
general practitioner and hospital clinician. Satisfactory
measures have not yet been evolved. Outcome studies,
especially in the surgical specialities, are likely to be
important measures of the quality of care.
American surgical audit practice
Audit is used in American surgical practice for the early
detection of poor surgical results (Kirk 2001, Singer 2001).
There is a customer-oriented approach for cultural and
economic reasons. It is a litigious society where the per-
formance and outcomes of surgeons and surgical estab-
lishments are closely scrutinized. Recent changes in the
UK in the wake of the Bristol affair, such as the publica-
tion of league and performance tables, suggest that some
or all of the following audit practices, which are standard
in the USA, will eventually become commonplace in the
UK.
Morbidity and mortality meetings are closed, confidential,
and attended weekly by the full surgical faculty, residents
and surgical medical students. The departmental chair-
man supervises and guides the debate and, most import-
antly, reaches a conclusion regarding each complication
or death. It is a basic premise that complications
inevitably occur in surgical practice. The chief resident
from each surgical team presents surgical throughput,
complications and deaths for the previous 1 week period.
The methods and outcomes of every surgeon are scruti-
nized in the light of current evidence and research, with
431
42
GENERAL CONSIDERATIONS
the acceptance that complications are an inevitable part of
surgical practice, and from which no surgeon is immune.
These are discussed fully, openly, with reference to con-
temporary evidence-based literature, to define complica-
tions or deaths that were preventable, and identify
corrective steps. This process is termed 'closing the audit
loop'. Passive documentation is unacceptable. The cor-
rective action is recorded, to be effected through letters,
guidelines and alterations in departmental policy
intended to reduce the risk of future similar errors.
Trainees are educated to learn vicariously (Latin vicarius
= substitute) from the errors of others, rather than from
their own failures.
Tissue committee meets monthly to compare every pre-
operative diagnosis with the histological specimen report,
to identify discrepancies and remedy them.
Quality assurance committee meets monthly to audit
outcome. For a specific condition they select a sample of
approximately 20 patients 7 case notes to compare out-
comes with national standards. Any significant lapse in
performance by individuals, teams, departments or
equipment is rectified.
Insurance companies have access, by consent of the
insured patients, to inspect the case notes on a periodic
basis to identify discrepancies in practice, such as pro-
longed stay, complications and significant increase in the
financial cost of patients' care.
ANALYSING AND CORRECTING FAILURES
1. For many years mortality and morbidity conferences
and audit meetings considered isolated failures - now
often termed 'adverse incidents'. A 'cause' was identified
by the senior participants and the meeting passed on to
the next incident. The atmosphere gradually changed
with demands by the public, and therefore by the poli-
ticians, for accountability by doctors for errors, increas-
ingly involving litigation. This was counterproductive
because admission that a failure had occurred inevitably
generated a demand for exposure of the 'culprit', so that
doctors became reluctant to report failures.
2. Contrast this with the situation in the airline
industry:
a. It is accepted that we all make mistakes and the
investigation is pursued on a 'blame-free' basis.
b. It is mandatory (Latin manus - hand + dare - to give;
a command given by hand, allowing no option) to report
any failure. It is not assumed that there is a single 'cause'.
c. The failure can be compared with other potentially
similar failures, from the accessible, international
database.
d. The best and most cost-effective method of prevent-
ing subsequent failures is determined.
e. The correction is implemented - and monitored
thereafter. The national and international aviation safety
boards have the power to order changes in procedures,
design, servicing and manning.
f . Whenever a disaster occurs, teams of skilled investi-
gators search for the causes, aided by flight and speech
recorders. The findings, and corrective actions required,
are promulgated internationally.
Key point
• We need to learn and apply the studies
available within the medical profession and
industry to avoid errors and improve safety
and particularly the US Federal Aviation
Administration's methods of improving civil
aviation safety.
3. Some of the approaches used:
a. System analysis failures demand a clear under-
standing of the failure or failures. This often demands
step by step examination of each piece of evidence, with
immediate recording of the findings.
b. Fault tree analysis was originally developed for the
US Air Force. After identifying the top 'undesired' event
causing failure, the analysis continues sequentially to
detect the subsidiary contributing causes.
c. 'What's different?' may be a valuable question when
an unexpected failure occurs. Changes in assessment,
decision making, technique, equipment, monitoring and
aftercare may have been overlooked.
4. Corrective action may involve system changes - but
some methods are preferable to others on grounds of
safety, reliability or convenience:
a. Improvement in methodology or equipment may elim-
inate failure. The most effective measure may be physi-
cally to prevent an error being committed. For example,
redesign of equipment may make it 'idiot proof. If acci-
dents have occurred because the wrong components were
connected, the connections may be altered so the correct
ones alone can be matched.
b. Monitoring systems may be introduced to identify
potential failures, such as regular, routine checking for
premonitory signs. In some cases automatic warning
systems can be built in to identify impending failures. In
medical practice, intensive care unit monitors relieve
nurses of constantly checking basal measurements, allow-
ing them to concentrate on other problems.
c. Replacement: components of equipment that fail may
be exchanged for new ones after intervals that are shorter
than the earliest recorded failure time.
432
AUDIT
42
d. Duplication and back up is an alternative to anticipat-
ing failure by early replacement of essential components.
e. Training methods may need to be adapted to make
sure that the risk of error is avoided.
f. Routines, protocols, algorithms can be changed but the
resulting benefit depends upon the conscientiousness
with which they are followed.
g. Checks are often employed. A junior may need to ask
approval from a senior to carry out a procedure. A junior
nurse may require to have a drug chart countersigned by
a senior before administering treatment. Routine checks
suffer from overreliance on them; they may become
routine and casually performed and are best reserved for
exceptional circumstances.
h. Warnings are an unreliable method because they are
overused. Visual warnings may not be seen, audible
warnings may not be heard.
Key points
Key point
There are two vital steps after identifying a
solution, or it is useless. Implement it. Evaluate
it.
Human factors
1 . The human factor analysis and classification system
(HFACS) was developed by the US military to investigate
human causes of flying accidents, and was applied to civil
aviation accident investigations. Errors are classified as
skill based, decision errors, violations of safety rules, or
perceptual errors. Other factors were adverse mental or
physical states and supervisory or organizational defects.
2. Acceptance that the hierarchical system of command
has defects (pilot > copilot > cabin crew) is defective and
has led to vital information being ignored. The emphasis
is on the aircraft crew working as a team, with each
member having input.
Changes needed to reduce or prevent medical errors:
1. We cannot totally eliminate errors. They are
inevitable in every human activity.
2. We need an easily accessible / national and inter-
national database of errors, adverse incidents and near
misses - not just the ones that have been harmful, but also
those that were averted or were potentially harmful. This
information can be gathered only in an atmosphere of
trust, without the threat of blame.
3. Errors, harmful or harmless, offer opportunities to
study potential improvements for the future in equip-
ment, systems, decisions and techniques.
• Although comparison between professions is
valuable, remember that many airline problems
are mechanical 'black and white'; many
biological and clinical problems are immensely
complex and are 'shades of grey'.
• Retrospective judgements and actions are less
secure when analysing biological failures
compared with mechanical and structural
failures.
4. In the past, out of a misplaced reluctance to 'tell
tales', we failed to challenge or report failures, mistakes,
lazy corner-cutting, incompetence and lack of commit-
ment by others. As with most failures, no harm usually
follows. Unfortunately, on occasion, other failures
develop simultaneously and disaster occurs. To avoid
disasters, everyone must perform to a high standard all
the time.
Ethics and confidentiality
You must protect the confidentiality of individual
patients; the same principles apply as in clinical confer-
ences, which form part of any academic programme.
Avoid identifying details of a patient in verbal or written
presentations; exclude them.
Protect the confidentiality of the professionals involved,
although this is difficult when, for example, one consul-
tant reviews the clinical records of another consultant's
patient. Nevertheless, this can be successful if you foster
an atmosphere of trust and collaboration. Obtain per-
mission from all consultants involved beforehand.
Anticipate and provide for what should happen if audit
reveals deficiencies in an individual's practice (Ellis &
Sensky 1991). The Joint Consultants Committee recom-
mends that you develop a plan of action, which they
suggest. If necessary, check if the Ethical Committee
requires to give permission before interviewing patients.
Computers
Acquire a working knowledge of the basic uses of a com-
puter. You can utilize word processing and graphics and
obtain access to databases such as MEDLINE from the
postgraduate medical centre. This is faster and more ver-
satile than searching Index Medicus. You may download
abstracts and papers to a personal computer. The internet
offers extensive and rapidly expanding reference sources,
including the Cochrane Collaboration. There are now
433
42_
GENERAL CONSIDERATIONS
many programs available as clinical information systems,
with outputs configured to aid audit, and also some pion-
eering ventures into clinical decision making and artificial
intelligence.
3. Audit helps you to identify areas for improving and
increasing knowledge, or suggests the need for research.
Remember that audit itself does not lead to new clinical
knowledge.
Hospital information systems
Only a few hospitals have completely integrated hospital
information systems covering every function, such as
clinical records, the scheduling of clinics, to the provision
of financial and manpower reports. Other hospitals have
a patient administration system (PAS), including the
'master index' (patients' demographic details) and
records of admissions and diagnostic codes. This repre-
sents the minimum upon which a hospital manager can
rely for information. PAS systems regularly pass aggre-
gated patient-level data according to a national minimum
data set to the local health authority. This, together with
contract activity information, enables local planning of
services.
In hospitals with this minimum configuration some
clinical departments have implemented their own infor-
mation systems, and these may provide sufficient infor-
mation on which to draw patient samples for audit
projects and some limited clinical data.
Current trends favour the integration of all these dis-
parate systems so that key patient-specific information,
once entered, is available throughout the organization.
The surgical trainee will almost certainly be involved in
the gathering of information for the production of a
discharge summary to the general practitioner and for
clinical audit.
Key point
• Research aims to identify 'the right thing to
do'. Audit assesses whether 'the right thing
has been done'.
4. Self-evaluation and peer review, common activities
in audit, are important components of postgraduate edu-
cation. To realize the full educational potential of audit,
you must learn the lessons arising from previous audit
meetings and review the conclusions acted upon.
IMPLEMENTING CHANGE
^l^^^'^viy^^^
rv&i^-t^V;:^^
1. Consider audit as a cycle, the first component of
which is the observation of existing practice to establish
what is actually happening (Fig. 42.1).
Adverse event?
Poor comparison with others?
Opportunity to improve?
EDUCATIONAL COMPONENT
1. Because of the manner in which audit was intro-
duced, with the intention of improving patient treatment
and cost-effectiveness, the educational value was a sec-
ondary consideration. It is now seen as vital that doctors
in training are taught the basic principles of audit.
Equally, conclusions drawn from the audit process should
be seen as an important feeder into education. The edu-
cational benefits of clinical audit have been considered in
depth by Batstone (1990).
2. Acquire and update your knowledge by critically
reviewing current practice and comparing it with pre-
defined standards. The audit process also enables you to
identify important features of clinical practice that help to
make teaching explicit. Audit is an active process of
review. If you are passive, and unclear whether your
current practice is inappropriate, you are unlikely to
respond to information through traditional channels such
as journals or continuing medical education (Lomas 1993).
Continuous
improvement
Further
changes
needed?
Re-audit
change
Observe
Monitor
change
Agree standard
of care
Data
collection
Compare and
implement
change
Fig. 42.1 The audit cycle. There should be no 'closure'
in the terminal meaning of the word, but there should
be 'closure' in the sense that no gap can be left in the
circle of reacting to circumstances that demand action to
improve them.
434
AUDIT
42
2. Now set standards of practice to define what ought
to happen and make a comparison between observed
practice with the standard.
3. Now implement change.
4. Observe again to see whether what has been
planned has been achieved.
5. You may need to decide whether practice needs to
change further, or whether the standards were unrealistic
or unobtainable.
6. This process has become known as the 'cycle of
audit' (Royal College of Physicians 1989) and the achieve-
ment of change has been termed "closing the audit loop'.
7. However, 'closure' implies completion. Always con-
tinue to observe results.
maintained, with cooperation replacing competition. The
quality of care is a priority for everyone.
Chief executives of trusts will be held accountable for
the quality of services they provide. This responsibility
for 'clinical governance' covers quality improvement (see
Ch. 43). The importance of clinical audit, led by clinicians,
in improving the quality of care for patients was recog-
nized in the previous NHS reorganization in 1989. The
new framework signals a more directed but integrated
role for audit within the organization. This can be seen as
an opportunity for audit to deliver the necessary changes
in practice which have been identified, and fulfil its
potential in improving patient care.
Key points
• Never cease to monitor results.
• Once you achieve improvement, if you relax
attention your improvement may relapse.
8. The provision of information on clinical activity
without any evaluation or suggestions for improvement
has almost no effect on clinical practice (Mitchell et al
1990). It needs to be targeted at decision-makers who had
already agreed to review their practice (Mugford et al
1991), A systematic review of 160 interventions directed at
changing clinical behaviour or health outcomes showed
that effects were small to moderate (Davis et al 1995).
Effective strategies were outreach visits, opinion leaders,
patient- media ted interventions and physician reminders.
Audit with feedback gives variable results.
9. The most commonly used approach involves the
publication of guidelines, which have been shown to
change practice and affect outcomes. Guidelines are more
likely to be effective if they have local involvement and
take into account local circumstances, are supported by
active educational interventions and use patient-specific
reminders, for example, in the medical notes (Effective
Health Care 1994). Guidelines need to be reviewed regu-
larly to establish 'ownership' and to incorporate the latest
research findings.
THE NEW NHS
The government white paper The New NHS: Modern,
Dependable (Department of Health 1997) outlines a new
'10 year' structuring and modernization programme. The
internal market is replaced by a system of integrated
care based on a partnership between health and social
care. The split between planning and providing care is
Summary
• Do you recognize the two aims of audit -
improved health care and clinical
education - must both be addressed?
• Do you accept that audit without
application of the findings is a wasted
'paper exercise'?
References
Aitken RJ, Nixon SJ, Ruckley CV 1997 Lothian surgical audit: a
15-year experience of improvement in surgical practice
through regional computerised audit. Lancet 350: 800-804
Bats tone GF 1990 Educational aspects of medical audit. BMJ
301:326-328
Bennett ], Walshe K 1990 Occurrence screening as a method of
audit. BMJ 300: 1248-1251
Billroth TH 1881 Clinical surgery: reports of surgical practice,
1860-1876. New Sydenham Society, London
Black N 1991 A regional computerised surgical audit project.
Quality Assurance in Health Care 2: 263-270
Buck N, Devlin HB, Lunn JN 1987 Report of a confidential
enquiry into perioperative deaths. King's Fund, London
Campling EA, Devlin HB, Hoile RW, Ingram GS, Lunn JN 1997
Who operates when? A report of the national confidential
enquiry into perioperative deaths. King's Fund, London
Davis DA, Thomson MA, Oxman AD, Haynes RB 1995
Changing physician performance: a systematic review of the
effect of continuing medical education strategies. JAMA 274:
700-705
Department of Health 1989 Working for patients (paper no. 6).
HMSO, London
Department of Health 1997 The new NHS: modern, dependable
(Cmnd 3807). Stationery Office, London
Donabedian A 1966 Evaluating the quality of medical care.
Millbank Memorial Federation of Quality 3(2): 166-203
Effective Health Care 1994 Implementing clinical practice
guidelines. University of Leeds, Leeds, vol. 1 : 8
Ellis BW, Sensky T 1991 A clinician's guide to setting up audit.
BMJ 302: 704-707
435
42
GENERAL CONSIDERATIONS
Ellis BW, Rivett RC, Dudley HAF 1990 Extending the use of
clinical audit data. BMJ 301: 159-162
Emberton M, Rivett RC, Ellis BW 1991 Comparative audit: a
new method of delivering audit. Bulletin of the Annals of the
Royal College of Surgeons 73: 117-120
Gallimore SC, Hoile RW, Ingram GS, Sherry KM 1997 The
report of the national confidential enquiry into perioperative
deaths, 1994-5. NCEPOD, London
Gruer R, Gordon DS, Gunn AA, Ruckley CV 1986 Audit of
surgical audit. Lancet i: 23-26
Hancock BD 1990 Audit of major colorectal and biliary surgery
to reduce rates of wound infection. BMJ 301: 911-912
Kirk J 2001 American mechanisms in place for the early
detection of poor surgical results. Bulletin of the Annals of
the Royal College of Surgeons 83: 307
Lomas J 1993 Diffusion dissemination, and implementation:
who should do what? Annals of the New York Academy of
Sciences 703: 226-235
Mitchell MW, Fowkes FGR 1990 Audit reviewed: does feedback
on performance change clinical behaviour? Journal of the
Royal College of Physicians 19: 251-254
Mugford M, Banheld P, O'Hanlon M 1991 Effects of feedback of
information on clinical practice: a review. BMJ 303: 398-402
National Centre for Clinical Audit 1996 NCCA clinical audit
action pack: a practical approach. National Centre for Clinical
Audit, London
Royal College of Physicians 1989 Medical audit. A first report -
what, why and how? RCP, London
Royal College of Surgeons 1991 Royal College of Surgeons
confidential comparative audit service. Bulletin of the Annals
of the Royal College of Surgeons 73: 96
Royal College of Surgeons 1995 Clinical audit in surgical
practice. RCS, London
Shaw CD 1989 Medical audit: a hospital handbook. King's
Fund, London
Singer A 2001 The Bristol affair - a view from New York.
Bulletin of the Annals of the Royal College of Surgeons
83: 306
Walshe K 1995 Evaluating clinical audit: past lessons, future
directions. Royal Society of Medicine Press, London
Walshe K, Spurgeon P 1997 Clinical audit assessment
framework. Handbook Series 24. HMSU, University of
Birmingham, Birmingham
Further reading
National Centre for Clinical Audit 1996 NCCA criteria for
clinical audit. NCCA, London
Royal College of Surgeons of England 1994 Guidelines for
clinicians on medical records and notes. RCS, London
Royal Society of Medicine 1990 Computers in medical audit: a
guide for hospital consultants to personal computer based
medical audit systems. RSM Services, London
Trent Regional Health Authority 1993 Guidelines on
confidentiality and medical audit. Trent RHA, Sheffield
Systems failure analysis
Berk J, Berk S 1993 Total quality management. Sterling,
New York
Wiegman DA, Shappell SA, Christina E 2000 A human factors
analysis of aviation accident data: an empirical evaluation of
the HFACS framework. Aviation Space and Environmental
Medicine 71: 328
These and many more are available on the internet by searching under
the title 'Systems failure analysis'
Also consult:
Reason J 1990 Human error. Cambridge University Press,
Cambridge
Useful links
http://www.ahrq.gov/qual/errback.htm Medical errors: the
scope of the problem: fact sheet.
436
H3 Clin
ical governance
B. Higgs
F
Objectives
• Understand the concept of and need for
clinical governance.
• Outline the framework/system of clinical
governance.
• Understand the role of clinical governance
in delivering quality health care.
INTRODUCTION
Public, political and professional pressure has been
growing to maintain and improve standards of patient
care throughout the National Health Service (NHS).
Clinical governance is one aspect of a system designed to
set, monitor and maintain standards of patient care. The
driving force for the introduction of clinical governance
was the perceived lowering of public confidence in the
NHS, a desire within the medical profession for systems
to be established that set, maintain and improve stan-
dards, and a demand for the government to fulfil public
expectations.
We should all aspire to improving the quality of health
care. Although most health professionals already provide
excellent quality care and many keep records or data sup-
porting their practice, there are inequalities within the
country, instances of substandard care and isolated cases
of abuse of the public's trust.
Clinical governance should identify areas where
patient care is suboptimal. However, not all of the issues
relate directly to the quality of clinical care provided, but
to other aspects that contribute to patient care which may
be economic and managerial, such as underfunding,
understaffing and lack of facilities, beds, equipment and
support services.
Hospital trusts, like other business activities, need to
be well organized to address these and other issues. Any
organization that functions as a single unit can be called
a corporate body. The system of corporate governance
(Greek kybernaein, Latin gubernare = control) is well
established in NHS Trusts, just as it is in the business
world. Within the Trust the responsibilities of those
working within a corporate structure are defined, and
the rules and procedures for pursuing the aims of the
business are decided and defined. The chief executives of
NHS Trusts are the designated accountable officers for
corporate governance.
Clinical governance is the clinical parallel of corporate
governance and defines the responsibilities of all those
who provide service for the patients, provide support for
their activities, monitor the results and ensure that the
quality of care provided meets the requirements of
the patients. The chief executives of NHS Trusts are
also the designated, accountable officers for clinical
governance.
CLINICAL QUALITY
The World Health Organization defines clinical quality
under four headings:
1 . Professional management - quality of the technical
aspects of care
2. Resource use - the efficiency of the management
3. Risk management - the risk of injury, illness or poor
outcome resulting from the care provided
4. Patient satisfaction.
To achieve optimal care we need to:
Set clear standards in each aspect of quality
assessment
Ensure that in each aspect the delivery of
service is the highest attainable
Monitor the outcome in each aspect and if
necessary correct deficiencies.
Audit is used to monitor clinical quality (see Ch. 42).
Medical audit provides a means of determining the
quality of the care by physicians and surgeons. This does
437
43
GENERAL CONSIDERATIONS
not encompass all that is included in clinical quality, and
clinical audit incorporates the total care by nurses and
allied health professionals in addition to doctors.
SCOPE OF CLINICAL GOV ERNANCE
1. For many years the majority of clinicians have
checked results /outcomes and compared them with pub-
lished results from highly respected centres. However,
these have usually been restricted to survival and result-
ing major morbidity. Clinical governance incorporates
these results, and more, with the overall service and
quality of patient care.
2. A patient visiting the outpatient clinic or general
practitioner, or one who is admitted to hospital, does not
judge the experience on the outcome alone. Patient satis-
faction does not depend only on your clinical skills, abil-
ities and judgements, but on the whole episode, which
involves medical, nursing, ancillary, technical, allied
health professionals, managers and secretaries, as well as
the availability of equipment and facilities. Good clinical
care may not compensate for poor facilities or equipment.
The process must, therefore, be a multi- and interdisci-
plinary event. Traditional boundaries and restrictive prac-
tices must be addressed and patient care needs to be more
integrated, involving all staff at all levels.
improves, there can be no doubt that useful information
will be gained, helpful to clinicians and patients alike.
Key points
Professional and clinical culture needs to place
the patient at the centre of the health care
organization.
The effects must extend outside any institution
into all aspects of patient care.
REPORTING OUTCOMES
■£37^^;^^
^^0^^^^^^
Following American experience, there is pressure for pub-
licly available outcome results for comparison between
units in the health service. Access to clinical information
in order to allow monitoring of clinical and organizational
practice appears to be a challenge for many organizations.
The quality of recording and classification is not uniform
and is often unreliable because of differences in facilities,
equipment, trained staff and commitment to accurate
recording. Moreover, the publication in 'ranked order' of
crude survival rates is valueless and could be harmful.
However, comparisons between different units with com-
parable data and informed interpretation may be useful to
both staff and patients. As information and data collection
Key points
Clinical governance challenges us to identify
and address clinical issues to improve them.
Imperfect information is better than no
information.
COMPONENTS OF CLINICAL
GOVERNANCE
1. Clinical effectiveness is concerned with ensuring that
the best care is provided by delivering treatments that
work. Clinical practice should be based on objective evi-
dence. There are several components of clinical effective-
ness that result in the delivery of evidence-based care (see
Ch. 12). Health workers should know what is clinically
effective practice, and how to apply that knowledge in
day to day practice. We should make sure that changes in
practice work to benefit patients.
2. Clinical audit (see Ch. 42) is a systematic and critical
analysis of the quality of clinical care, including the pro-
cedures for the diagnosis, treatment and care, the associ-
ated use of resources and the resulting outcome and
quality of life for the patient. It is used to examine current
practice in relation to a standard. If there is a gap between
current practice and the standard, then practice must be
changed to close the gap. The process is then reaudited to
make sure that the loop is closed and the audit cycle is
completed.
3. Risk management is clinical and non-clinical, and is
proactive - instigating changes in anticipation of future
developments:
a. Clinical risk management is achieved by establish-
ing a process of reporting by all members of the clinical
team whenever unexpected, adverse or 'near miss' clini-
cal incidents occur, whether or not actual harm results.
The reports are reviewed to identify any immediate action
that should be taken to avoid future potentially danger-
ous incidents. The aggregated data, together with recom-
mendations, are fed back to all members of the care team.
This process allows immediate action on incidents when
required and the aggregate data draw attention to risks
that may occur seemingly in isolation. When analysed
over time, patterns may emerge, in isolation or across the
whole establishment, so that steps can be taken to reduce
or eliminate the risk.
b. Non-clinical risk management is applied to con-
siderations such as fire and electrical safety.
438
CLINICAL GOVERNANCE
43
4. Research and development supports clinical govern-
ance by providing the evidence base for good and effec-
tive health care. It is a popular misconception that to be
of any value the research has to be funded by the Medical
Research Council, be international, multicentred and
published in a highly rated journal. While national and
international research collaborations help to identify
modern and effective treatments, many improvements to
the provision of quality health care are made at local level.
There is an obligation on all trusts to support, train and
develop their staff to enhance the staff's research skills
and hence improve the quality of care delivered.
5. Quality indicators and monitoring of quality: Trust
boards identify quality indicators, monitor them and act
accordingly. This is achieved by tracking all national indi-
cators that apply to trusts (Department of Health and
Dr Foster), the most important of which are the clinical
indicators including mortality, other incidents and com-
plaints. There are always problems with standardization
and this makes comparisons difficult. It is vital that data
relating to clinical quality are accurate. All clinicians have
a responsibility to ensure that data about their patients are
correct.
6. User perspective is important: services must be centred
on patients' needs. Strangely, this is an area that pre-
viously was rarely addressed in a systematic, cohesive
corporate manner. Clinical governance will not succeed
unless the patients are involved in the initiation of trust
strategy. There are many different mechanisms for seeking
feedback from patients and involving patients in planning
health care. In addition to clinical needs, it is necessary to
address information, privacy, dignity and religious and
cultural aspects. Feedback can be obtained by question-
naires, surveys, audit and interviews. However, direct
involvement of patients in 'users' groups' is essential to
enable new ideas, concerns and help with planning new
and existing services to be dealt with.
7. Education, training and continuing professional develop-
ment are essential for the provision of high quality care
(General Medical Council 2001). There must be a balance
between teaching and training. Support must be provided
both for trainers and teachers. Lifelong learning should
involve a systematic approach whereby doctors and other
health professionals are helped to identify development
needs that will enable them to do their jobs better and
move toward their career goals. Postgraduate medical
organizations are well placed to help carry this forward.
All staff should have a personal development plan which
balances service needs and career aspirations.
Key points
• All elements of clinical governance must be
active in your trust.
• Are you involved in all these aspects?
8. Other systems and relationships that support or com-
plement clinical governance: in addition to long estab-
lished organizations within the National Health Service,
new ones have been created (see Fig. 43.1). 'Outside'
bodies and national principles involved in clinical
governance in your Trust are:
a. National Institute for Clinical Excellence (NICE). This is
a Special Health Authority It was set up to provide a
strong lead on clinical and cost-effectiveness by drawing
up guidelines based on scientific evidence and to advise
on best practice.
b. National Service Frameworks (NSFs). These are designed
to set national standards and define service models for a
specific or defined service care group. They are, or put in
place, strategies to support implementation /establish
performance milestones.
Patient and public
involvement
0>
National Institute for Clinical Excellence
National Service Frameworks
~"*V~
I
Professional
self -regulation
v
Clinical
governance
>^
Lifelong
learning
I ▼
A^
^
Commission for Health Improvement
National Performance Framework
National Patient and User Survey
^
>
Clear STANDARDS of service
Dependable local DELIVERY
>
MONITORED standards
Fig. 43.1 It is important to note the central position of clinical governance.
439
GENERAL CONSIDERATIONS
c. Commission for Health Improvement (CHI). Established
to assure, monitor and improve the quality of care in the
NHS in England and Wales. It will provide national lead-
ership to develop and disseminate clinical governance
principles. The Commission will visit every NHS Trust
every 4 years and independently scrutinize local clinical
governance arrangements to support, promote and
deliver high quality services. By 2003 it is proposed that
NHS performance indicators will be transferred to CHI
and will be published.
d. NHS Performance Framework. This will be used to
move toward assessing performance of the NHS in the
round, covering quality and efficiency. A set of national
indicators will measure progress against main targets. It
will encourage benchmarking between similar NHS
organizations and underpin national and local perfor-
mance and accountability arrangements. High level
performance indicators (e.g. deaths, surgery rates, cancer
detection, hospital stay etc.) will be used to ensure a more
rounded assessment of NHS performance. Depending on
their performance against the Performance Assessment
Framework, all NHS organizations will annually and
publicly be classified as 'green' , 'yellow' or 'red'. Red
organizations will be those who are failing to meet a
number of the core national targets.
e. Professional organizations and Royal Colleges. The pro-
fessional bodies as well as the newly established Medical
Education Standards Board (replacing the Specialist
Training Authority) will work together to maintain
quality and improve training.
The Commission for Health Improvement will join with
the Audit Commission to form the Commission for
Healthcare Audit and Inspection (CHAI). This body will
lead inspections in the NHS and the private health care
sector and be responsible for all financial and perform-
ance audit as well for the quality of the assessment work
which CHI has been doing.
Key points
(HimPs). However, hospital trusts do not work in isola-
tion! Health authorities, hospital trusts, primary care
trusts and social services work together to develop a
3 year HimP. This plan should consider national and local
priorities. The national priorities for 1999-2000 were cor-
onary heart disease, mental health, cancer and antibiotic
prescribing. Since then, National Service Frameworks
(NSFs) for diabetes and care of older people have been
introduced, and NSFs for renal services, children's ser-
vices and long-term conditions focusing on neurological
disorders are in preparation.
2. Local priorities take into account the needs
and special circumstances of the local population. If
these priorities are to be addressed there needs to be a
mechanism for making certain that the standards
required are monitored and delivered. Similarly there
needs to be evidence that the priorities are being met
and /or pointers toward where resources are being used
effectively.
3. This combination of agreeing and setting priorities
in planning, purchasing and delivering health care,
introducing clinical governance and measuring the
outcomes by means of the National Performance
Assessment Programmes should result in more modern
and effective healthcare delivery by including all the key
partners in planning and tackling the root causes of ill
health.
• Do you understand the interrelationships of
clinical governance?
• Do you understand the role of the outside
bodies?
Summary
• Do you know who is ultimately responsible
for maintaining overall clinical standards
in your hospital?
• Do you know the range of people who
come into contact with patients or provide
a service to them?
• Do you appreciate the range of
experiences on which patients base their
assessment of outcome?
• Do you accept individual and collective
responsibility for the reputation and
quality of care delivered by your firm,
unit, hospital, health service?
HEALTH IMPROVEMENT
PROGRAMMES AND NATIONAL
SERVICE FRAMEWORKS
1. Clinical governance is an integral part of developing
and implementing Health Improvement Programmes
References
General Medical Council 2001 Good medical practice, 3rd edn.
GMC, London (www.gmc-uk.org/standards/good.htm)
440
CLINICAL GOVERNANCE
43
Further reading
Clinical governance: quality in the new NHS (HSC 1999/065).
HMSO, London
Bloor K, Maynard A 1998 Clinical governance: clinician heal
thyself. Institute of Health Service Management, London
NHS Executive 1999 Quality and performance in the NHS: high
level performance indicators. HMSO / London
NHS Executive 1999 Quality and performance in the NHS:
clinical indicators. HMSO, London
Secretary of State for Health 1997 The new NHS, modern
dependable. HMSO, London
Swage T 2001 Clinical governance in health care practice.
Butterworth-Heinemann, Oxford
441
Economic aspects of surgery
R. W. Hoile, 6. Douglas
0F
Objectives
Understand some basic principles behind
economic considerations in surgical practice.
Recognize the potential conflict between
clinical freedom, medical ethics and the
logic of health economics.
Examine areas of clinical practice where
surgeons can influence the costs of surgery.
of the disease, hospitalization and time off work. While
we should be striving to deliver a cost-effective healthcare
system, we should not lose sight of these personal costs.
Measuring cost effectiveness is an unfamiliar process to
clinicians, but it is important in evaluating and practising
modern surgery. Before the cost effectiveness of any sur-
gical management is understood, it is necessary to under-
stand some of the principles, definitions and accounting
practices that are applied to problems of health care and
the way in which they may affect clinical decision making.
INTRODUCTION
This is probably a subject which, up to now in your
surgical career, you have not needed to think about or
understand. Before you progress much further you will
undoubtedly be exposed to economic considerations and
the consequences of your actions, so it is worthwhile dis-
cussing some of the principles used when addressing this
topic.
The National Health Service was developed on the
principle of fairness and that health care was free to the
patient at the point of delivery. With rising costs of health
care, limited resources and the heightened expectations of
our patients, it is inevitable that questions are asked about
cost. There is also a debate about the quality versus quan-
tity of care and the total benefit to the community. Will the
economic arguments take over and conflict with good
patient care, or can good economic strategies mean better
patient care? At all times in this debate keep central the
outcome for your patients.
MEASUREMENT OF COST
EFFECTIVENESS
COST EFFECTIVENESS: WHAT DOES IT
MEAN?
There are four ways of interpreting cost effectiveness in
clinical practice.
1. Cost savings: this can also be considered as avoided
costs, or the estimated costs caused by the disease process
that can be avoided by surgical intervention; for example,
appropriate treatment of venous insufficiency in the leg
can prevent the development of subsequent, costly (in all
senses of the word) chronic venous ulceration.
2. Effective improvement of health care.
3. Cost savings with equal or better health outcome:
this requires no compromise by accountants, financial
directors or clinicians - it is a 'win-win' situation.
4. Additional benefits worth the additional cost: judge-
ment is needed to decide whether additional cost is worth
the anticipated benefit and to select the course of action
with the least cost at the most probable benefit. Both a high
dependency unit (HDU) and an intensive care unit (ICU)
give high benefit for cost. Similarly, critical care outreach
teams effectively identify critically ill patients and advise
on management; they are expensive but cost effective.
The measurement of cost effectiveness can be considered,
in simple terms, as synonymous with economic evalu-
ation. The cost of surgery is not just monetary but also
personal and social. For the patient, there is pain, suffer-
ing, time spent in hospital and the economic consequences
Key points
Surgeons should consider both clinical benefit
and cost effectiveness together.
442
ECONOMIC ASPECTS OF SURGERY
44
• Clinical freedom allows you to choose the best
treatment for a patient (based on the evidence,
clinical knowledge and understanding) but
remember that resources are limited.
• Unwise use of resources is poor cost
effectiveness.
• An unnecessarily expensive remedy for one
patient may deprive other needy patients of
valuable treatment.
HOW ARE BENEFITS MEASURED?
1. Cure.
2. Increased life expectancy.
3. Improved quality of life. One method of evaluating
the value of a year of healthy life is the calculation of
quality-adjusted life years (QALYs). One year of life
in full health is 1 QALY.
HOW ARE COSTS MEASURED?
• Direct costs are those borne by the healthcare system,
community and family.
• Indirect costs are those borne by the individual, family,
society and employer, such as time spent in hospital,
loss of earnings and loss of productivity.
• Intangible costs are those borne by the patient, such as
pain, anxiety, grief, suffering and loss of leisure. Death
following an operation is also often considered as an
intangible loss.
Hospital attendances, medical and surgical risks, mortal-
ity, resulting disability, management of complications and
failures, contribute to all three cost evaluations.
HOW CAN YOU INFLUENCE HOSPITAL
COSTS?
1. Use resources efficiently and appropriately. The
introduction of day surgery as a low cost /high
throughput service reduces the cost of procedures
without increased morbidity. Short-stay, 5 day wards, low
dependency units and hotel use also reduce costs, are not
detrimental and may be advantageous. Preadmission
clinics, which may avoid last minute cancellations, are
also proven to be cost effective.
2. Avoid investigative and operative techniques that are
outdated or of unproven use (see Ch. 12). 'Routine' inves-
tigations for all admissions are valueless unless they influ-
ence subsequent management (see Chs 6, 15). Order the
fewest tests that will provide the speediest, most specific
and reliable results. Tests requested out of hours cost more
to provide so avoid them if they can be deferred. However,
remember that sometimes a quicker diagnosis and prompt
action may ultimately shorten hospital stay and speed
recovery. Can you justify your requests?
3. Critically assess the value of procedures that
demand expensive technological back-up or instrumen-
tation. The gains must be balanced against the costs;
laparoscopic colonic surgery reduces hospital stay,
recovery and back-to-work time. On the other side of the
balance sheet there may be the costs produced by a longer
operating time, increased risks of thromboembolism,
ureteric injury and concerns about the adequacy of resec-
tion. Patient preference must also be considered; for
example, in hernia repair the cost effectiveness of the
'open' and endoscopic techniques are roughly compar-
able but many patients will express a preference for
minimal access procedures. You could probably make
considerable cost reductions and feel more at ease with
resource implications if you and your clinical colleagues
could agree 'best practices' for selected procedures,
develop local protocols and adhere to them; for example,
you might agree to perform laparoscopic procedures but
carefully define the circumstances when it would be
acceptable to use the more expensive disposable pieces of
equipment.
4. Place the patient's interests above those of academia
or research. Patient screening (see Ch. 41) must be shown
to be cost effective. Society must participate in the deci-
sion to introduce screening or compliance will be poor.
5. Keep complication rates low. Postoperative compli-
cations are expensive and can spoil any attempt to
improve the cost effectiveness of surgery. The manage-
ment of complications may triple the costs of an uncom-
plicated procedure. Avoid complications at all stages of
assessment, decision making, preparation, active treat-
ment, recovery, discharge and review. Audit your results.
6. Do not be afraid to develop new ideas and think lat-
erally if you can show a benefit. It is appropriate to seek
funding if there is a proven or predicted benefit for the
service or the patients. For example, an emergency ad-
missions unit (such as that established at Eastbourne
General and other hospitals) allows intensive preadmis-
sion assessment and may prevent 20% of admissions. This
saving in bed occupancy more than justifies the cost of
such a unit.
Key points
• Avoid unnecessary costs.
• Recognize that the benefit and outcome for
the patient are the most important factors.
443
44
GENERAL CONSIDERATIONS
Choose relevant investigations.
Assess the evidence concerning the efficacy
and outcomes of operative interventions.
Do not assume that you have to operate: think
carefully about the benefits first.
Take precautions to minimize complications.
Only adopt new techniques after proper
evaluation.
Develop guidelines for 'best practice' for
selected common procedures.
Liaise with departmental managers in order to
determine the service requirements for your
local population.
CONCLUSIONS
^^^S&yPXui'&^'^X
Thinking about the economics of health care raises issues
that are sometimes uncomfortable. There are questions
about waste, the inappropriateness of investigations and
operations, rationing, cost containment, ethics, etc. The
response to these questions needs to be well thought out
and workable. It is possible to set professional standards
and deliver appropriate care while eliminating the
unwarranted use of medical resources. It is easy to "do
something', particularly when faced with an individual
patient, but perhaps we should stand back, take a broader
view and consider whether an action for the individual
patient is appropriate and /or cost effective. A multitude
of tests and complex procedures do not necessarily
produce an accurate or speedy diagnosis, a lower mor-
bidity or mortality, or 'better' health care. Professional
guidelines and clinical audit may sometimes help us
when it is necessary to say 'no'. A partnership between
clinician and manager may help rationalize the provision
of a surgical service, with maximum benefits to all
concerned.
We have not found all the answers yet but you must
begin to address these difficult issues.
Summary
• You should recognize that the costs of
surgery (and health care in general) are
rising but resources are limited.
• Health economics provides a logical
framework for the allocation of resources.
• You can reduce costs without
compromising clinical freedom and patient
care by investigating wisely, operating
sensibly and keeping complications low.
'Choose well, cut well, get well.'
• You may perceive a conflict between your
medical ethics and the economic logic
applied by your hospital accountants and
trust financial director. However, having
read this chapter, you will appreciate that
the aim of both disciplines is to promote
health and alleviate suffering. The surgical
economic argument is just one more tool
for you to use when making decisions
about the care of your patients.
• Consider the wider implications of your
decisions and actions.
Further reading
Gray AJ, Hoile RW, Ingram GS, Sherry KM 1998 The report of
the national confidential enquiry into perioperative deaths
1996/97, NCEPOD, London
Hicks NR 1994 Some observations on attempts to measure
appropriateness of care. BMJ 309: 730-733
Hodgson K, Hoile RW 1996 Managing health service contracts.
WB Saunders, London
Jefferson T, Demicheli V, Mugford M 1996 Elementary economic
evaluation in health care. BMJ Publishing Group, London
O'Brien B 1986 'What are my chances doctor?' A review of clinical
risks. Health Economics Research Group, Brunei University
Williams A, Anderson R 1985 Efficiency in the social services.
Blackwell, London
444
Statistical concepts: a tool for
evidence-based practice
R. W. Morris
Objectives
• If you wish to apply up-to-date published
research to your clinical practice, you need
to grasp basic statistical concepts and
common techniques that quantify the
benefits of new interventions and
diagnostic tests. You must be able to
appraise critically the design of research
studies, apart from understanding the
handling of quantitative data in published
research. You can then practise evidence-
based medicine (see Ch. 12).
• If you wish to carry out your own
quantitative research, you must have a
firm grasp of statistical principles. In this
chapter I shall aim to provide a
comprehensible outline of various
statistical techniques employed in surgical
research, rather than attempt a detailed
coverage. For this reason I have
recommended useful books for further
reading.
CLINICAL SCENARIO
s ifss'^f ^k*-*; .'■$> ?%&%■■
Mr Dennis Gray is a 49-year-old gardener. He was
diagnosed as having carcinoma of the rectum after
presenting to his general practitioner with bleeding
on defecation. A CT scan of the abdomen suggests
that the tumour is about 3 cm in diameter and has
not yet become locally invasive. There is no sign of
metastatic spread. Mr Gray is scheduled for curative
resection with preservation of anal function. You
feel that adjuvant chemotherapy is not necessary in
this case in view of the many favourable prognostic
features. The consultant, however, wishes to maxi-
mize Mr Gray's chances of complete cure by admin-
istering an intraportal regimen of fluorouracil,
500 mg m~ 2 , on the first day after surgery and a con-
tinuous heparin infusion for 7 days. The patient,
who has three young children, is keen to follow
any regimen that improves his chances of long-term
survival.
Many clinical questions might arise during Mr Gray's
encounters with both the general practitioner and the
surgeon. These may include, in particular:
• Diagnosis. How important is bleeding on defecation in
establishing the presence of a rectal carcinoma?
• Prognosis. What probability of long-term survival (e.g.
for 10 years) does Mr Gray have?
• Therapy. Will adjuvant therapy increase Mr Gray's
chances of a complete cure? If so, by how much?
All three of these questions may potentially be answered
by appropriate studies.
1. It is unlikely that any routine test carried out to
establish the presence or absence of disease will be
entirely accurate. When applying such a test however,
knowledge of its accuracy will be helpful in interpreting
the result gained. Traditionally this will be expressed in
terms of two quantities, namely the sensitivity and speci-
ficity. These can be assessed by a study in which the
routine test has been applied to a number of subjects
where the true presence or absence of disease has been
established, usually by a diagnostic test seen as the 'gold
standard' (Table 45.1).
2. A study was carried out by Fischer et al (1991) on
patients with new knee conditions. All subjects under-
went arthroscopy, which was taken as the gold standard,
as well as magnetic resonance imaging (MRI). A compar-
ison was made for 911 patients on whether arthroscopy
445
45 *
GENERAL CONSIDERATIONS
Table 45.1 Test for presence/absence of disease
Disease present
Disease absent
Totals
Test positive
Test negative
Totals
True positive
False negative
AH with disease
present
False positive
True negative
Ail with disease absent
AH test positive
AH test negative
AH in study
and MRI showed the presence or absence of a medial
meniscal tear. The results were as shown in Table 45.2.
Of 473 subjects who actually had a medial meniscal
tear (according to the arthroscopy), 440 were correctly
picked up by the MRI. Thus the sensitivity of the test was
440/473 = 0.93, or 93%. The MRI missed 7% of the menis-
cal tears.
Of 438 subjects who did not have a medial meniscal
tear, 367 were correctly excluded by the MRI. Thus the
specificity of the test was 367/438 = 0.84, or 84%.
Thus we know that if someone has a medial meniscal
tear, there is a 93% probability that they will be picked up
by an MRI. If they do not have a meniscal tear, there is an
84% chance that this diagnosis will be correctly excluded
by an MRI.
3. As a clinician faced with an individual case,
however, the sensitivity and specificity are of little direct
value to you. The idea of performing an MRI is that its
result will become available before an arthroscopy is per-
formed. The question therefore is not 'If this patient had
a meniscal tear, how likely is it that a positive MRI result
would be shown?' but rather 'When given a positive MRI
result, how likely is it that a medial meniscal tear is actu-
ally present?' The latter question leads to consideration of
the positive predictive value (PPV).
From the data above, the PPV is 440/511 = 0.86, or 86%.
In other words, 86% of all positive MRI scans indicate a
true tear of the medial meniscus.
By analogy, another useful statistic is the negative pre-
dictive value (NPV). 'When given a negative test result,
how likely is it that a medial meniscal tear is actually
absent?'
Table 45.2
Presence/absence of a
medial meniscal
tear
Tear present Tear absent
Totals
MRI scan
440 71
57?
positive
MRI scan
33 367
400
negative
Totats
473 438
911
The NPV is 367/400 = 0.92, or 92%. In other words, 92%
of all negative MRI scans indicate absence of tear in the
medial meniscus.
4. The PPV and NPV are of more intuitive use to you
than the sensitivity and specificity. Unfortunately, their
appeal may be illusory. They depend very heavily on the
actual prevalence of the condition in the population
under study. In the study generating the data shown in
Table 45.2, the prevalence of a meniscal tear was just over
50% (473/911). If a similar study was carried out on a
population where the true prevalence was lower, then the
PPV would be less than calculated above. The NPV
would be even higher. For example, if the prevalence
were 33%, the PPV would fall from 86% to 74%. The NPV
would increase from 92% to 96%.
5. Fagan's nomogram. A more directly useful approach
comes through use of Bayes theorem. When applied to
diagnostic testing, it runs as follows:
pretest odds x likelihood ratio = post-test odds
The pretest odds will be based on a hunch from the clini-
cian prior to application of a diagnostic test such as MRI.
The clinician, having taken a clinical history, may have a
rough subjective idea of how probable it is that the patient
has a medial meniscal tear. The probability may then be
converted into an 'odds', but this step can be omitted by
using Fagan's nomogram (shown and explained in detail
below).
The likelihood ratio (LR) will incorporate information
given by the diagnostic test. When the test gives a posi-
tive or negative result, the LR can take one of two poss-
ible values. If the MRI result is positive:
LR+ =
sensitivity
100 -specificity
93
100-84
= 5.8
If the MRI result is negative:
100- sensitivity
specificity
100-93
84
= 0.08
446
STATISTICAL CONCEPTS: A TOOL FOR EVIDENCE-BASED PRACTICE
45
If you think there is a 50% probability that a meniscal tear
is present, then the pretest odds are 50/50 = 1.
A positive result means that post-test odds = 1 x 5.8 =
5.8. The post- test probability is then around 85%. This
would probably be high enough to indicate a need for
arthroscopy,
A negative result means that post-test odds = 1 x 0.08
= 0.08. The post- test probability is then around 7.5%.
This is probably low enough to render arthroscopy
unnecessary.
Fagan's nomogram (Fig. 45.1) allows direct mapping
from pretest probability to post-test probability once we
know values for the likelihood ratio for a positive and for
a negative result. Use of a ruler will show that a pretest
probability of 50% , combined with a likelihood ratio of
5.8, will translate into a post-test probability in excess of
80%. Similarly a pretest probability of 50%, combined
with a likelihood ratio of 0.08, will translate into a post-
0.1
%
0.2-
0.5-
1
2-
5-
10-
20-
30
40 H
50
GO
70-
80-
90-
95-
1000
500
200
100
50
20
10
5
2
1
99
Pretest
probability
0.5
0,2
0.1
0.05
0.02
0.01
0.005
0.002
■0.001
Likelihood
ratio
99
-95
-90
-60
70
-60
-50
40
-30
-20
10
-5
-2
-1
0.5
0,2
%
01
Post-test
probability
test probability between 5 and 10%. Usually, approxi-
mate answers will be sufficient for decisions on clinical
management.
Key points
Fig. 45.1 Fagan's nomogram.
• Studies that generate the sort of data shown in
Table 45.2 are more useful if their methodology
is sound.
• Many studies are carried out on two
independently selected groups of subjects; one
group with confirmed disease, one healthy
control group.
• This ignores the spectrum of pathologies seen
in clinical practice. It is likely to produce an
unduly optimistic picture of the test's ability to
discriminate between differential diagnoses.
• A study will avoid spectrum bias if it has
included a cohort of consecutive cases seen in a
realistic clinical setting.
6. It would be ideal (although perhaps difficult in prac-
tice) if the result from the test under consideration (e.g.
MRI) and the gold standard diagnosis (arthroscopy) are
independently ascertained. If you already know the result
of the MRI before undertaking the arthroscopy, your
judgement will inevitably be influenced in marginal cases.
Returning to the scenario of Mr Dennis Gray, the 49-year-
old gardener, it might be asked whether there are studies
that address the question of adjuvant therapy. The study
by the Swiss Group for Clinical Cancer Research (1995)
may help to resolve the question.
Answer the following questions before deciding
whether the Swiss study will help the decision:
• Can the methods of the study be trusted?
• What do the results of the study actually show?
• Are the patients in the study like Mr Dennis Gray?
Methods
1. A study that evaluates the effects of a new interven-
tion should be a randomized controlled trial (RCT). By this we
mean that the patients entering the study should be allo-
cated at random to one or other treatment (e.g. adjuvant
therapy, or not). The purpose of this is that the two treat-
ment groups should, on average, be like each other in every
respect other than the treatment given. The two groups of
447
4
GENERAL CONSIDERATIONS
subjects should have the same average age, and the same
ratio of males to females, and so on. Not only should there
be a balance of known prognostic variables, there will also
be a balance of unknown prognostic variables.
2. Random numbers are generated to produce an
assignment to one of the treatment groups for each
patient entering the study. This should to be done so that
the investigators cannot predict the assignment before
entering the subject into the study. Thus, assignment by
whether the patient's date of birth is odd or even, or
alternating assignments between the treatment groups, is
unsatisfactory. Multicentre trials typically involve tele-
phoning a central office to receive a random assignment.
3. Once patients are assigned to a particular treatment
group, they should stay in that group for analysis
purposes. This principle, known as 'intention-to-treat',
should be adhered to even if the patients or doctors are
unable to follow the treatment protocol.
Of course this depends on whether it has been possible
to obtain outcome data on every patient. Sometimes
patients drop out of a study altogether and it is not poss-
ible to analyse all patients according to their original
treatment group, simply because the required data have
not been collected. Sometimes it may be possible to
impute plausible values, but often some subjects simply
have to be omitted from analysis. The proportion of sub-
jects Tosf in this way, out of all those randomized, should
not be too high.
4. 'Blinding' is desirable to prevent subjective bias. For
placebo-controlled drug trials, neither the patient nor the
doctor should know what treatment the patient has
received. Such an ideal is difficult to achieve when surgi-
cal interventions are being assessed. In trials of coronary
artery bypass grafting versus percutaneous angioplasty,
neither the patient nor the surgeon may be blinded. Yet
there may be scope for blinding study personnel who
need to read X-rays or code death certificates to assess
outcome in all the patients.
Results
1 . The first table of results in papers reporting an RCT
should compare the baseline characteristics of the two
groups of subjects. The process of random allocation
should demonstrate broad similarities. However this
balance may not occur if the study is small. If so, any dif-
ferences in outcome later reported should be weighed
alongside possible differences in baseline characteristics
of the groups.
2. You must be clear about the choice of the primary
outcome variable, or endpoint. In the Swiss trial, there
were two endpoints. One endpoint simply concerned
death of the patient. The other concerned 'disease-free
survival', which was denned when a patient did not die
and had no evidence of relapse or a second primary
tumour. We shall consider the simpler 'death' endpoint.
3. It was estimated that of those who received adjuvant
therapy, 43% died within 5 years. For those who did not
receive adjuvant therapy, 52% died. A comparison can be
made between these two rates, both in absolute terms and
in relative terms.
Absolute differences
The absolute risk reduction (ARR) is the event rate in the
control group minus the event rate in the intervention
group = 52 - 43% = 9%. Thus, for every 100 patients who
received adjuvant therapy, nine (9%) fewer subjects died
than would have otherwise been the case.
A popular statistic to express this idea in another way
is the number needed to treat (NNT). This is the reciprocal
of the ARR: NNT = 100/ARR = 100/ 9 = 11. Thus for
every 1 1 patients treated with adjuvant therapy, one fewer
patient will die within 5 years.
Relative differences
When considering the ARR, we concentrated on sub-
tracting one death rate from the other. Another approach
is to divide one death rate by the other: Relative risk (RR)
= 43/52 = 0.83. In other words, use of adjuvant therapy
reduces the probability of death within 5 years to 0.83
(83%) of what it would have otherwise been; that is, 17%
of the risk is removed {relative risk reduction, or RRR).
The pie chart (Fig. 45.2) shows the effect. Suppose the
entire circle represents the risk of death in the next 5 years
for Mr Dennis Gray if he is not offered adjuvant therapy.
The white slice represents the proportion by which his
risk is reduced if adjuvant therapy is administered (17%
of the total). The black region represents the proportion of
his risk still remaining.
Odds ratio
This is another relative measure and in many circum-
stances may be interpreted in a similar way to the relative
17%
83°/
Fig. 45.2 Pie chart showing relative risk reduction.
448
STATISTICAL CONCEPTS: A TOOL FOR EVIDENCE-BASED PRACTICE
risk; however, it uses the idea of an 'odds' rather than a
'risk'. In everyday life, the term 'odds' is most mentioned
in the context of placing bets! When a horse is given odds
of 4:1, it means that there is supposed to be one chance of
it winning to four chances of it not winning. So its prob-
ability of winning is 1 in 5, or 20%.
The probability of death for Mr Gray if he is not treated
with chemotherapy is 0.52 (or 52%). Therefore his odds is
52/(100 - 52 ) = 1.08. Similarly, if he is treated with adju-
vant therapy, his odds will be 43/(100 - 43) = 0.75. The
odds ratio is the odds if treated with adjuvant
therapy /odds if not treated with adjuvant therapy =
0.75/1.08-0.69.
When an event is uncommon (e.g. occurs less than 10%
of the time), the odds ratio and the relative risk tend to
converge to similar values. They are rather different in the
present example, and the odds ratio is probably a more
robust relative measure. However, if fewer subjects died
when given the intervention (as here), then both the rela-
tive risk and the odds ratio will be less than one.
to be larger than 0.97, and it is unlikely to be below 0.57.
At the optimistic end, the true hazard ratio may be as
small as 0.57, suggesting that the hazard of death could
be reduced by almost one half. At the pessimistic end,
the true hazard ratio may be 0.97, suggesting the hazard
would be reduced by only 3%. So the results of the study,
which estimate a 26% reduction in the hazard, are also
compatible with a substantial reduction on the one hand,
or a miniscule reduction on the other. It could be argued
that the results of the study are therefore not very
precise.
Application
There is always some way in which your particular
patient (e.g. Mr Dennis Gray) may seem unique. However
the question 'Is my patient so different from those in the
study that its results cannot apply?' should supply the
right perspective.
Confidence intervals
1 . A group of subjects recruited to a study is a sample.
Our true interest is not in the subjects studied but the
underlying population from which the subjects were
drawn. Any summary statistic (for example, a relative
risk) calculated from a sample is an estimate. We want to
know the true value of the relative risk, say, for the
population. It is inevitable that if we repeated the whole
study with a similar number of subjects included, we
would get a slightly different estimate. We therefore
wish to establish a confidence interval for the relative risk,
based on the estimate from the study we have carried
out.
2. The mathematical theory behind the construction of
a confidence interval cannot be covered in this chapter,
but the idea is to provide a range within which the true
relative risk is likely to lie. Typically a 95% confidence
interval is quoted.
3. In the Swiss study, the authors quote a hazard ratio
(yet another relative measure!), which is a useful statistic
when the data consist of differing follow-up times. The
hazard ratio of death in those treated with adjuvant
therapy was 0.74. This means that at any time point after
surgery, those treated with adjuvant therapy are 0.74
times as likely to die at that point as those not given adju-
vant therapy (26% reduction in the 'hazard'). The authors
also quote the 95% confidence interval as 0.57 to 0.97.
What does this mean?
4. Formally, there is a 95% probability that the confi-
dence interval calculated and quoted above will contain
the true hazard ratio for the entire population. In prac-
tice, we may assume that the true hazard ratio is unlikely
Sample size calculation
If you wish to carry out an RCT you need to answer the
question of how many subjects to study. This depends on
answering several questions, including a specific guess
of how much difference the new intervention might
make.
First, there is the need to define a primary outcome
measure. In the Swiss trial, this was either death, or
disease-free survival. Secondly, we should estimate how
much difference the intervention of interest (adjuvant
therapy) would make to this primary outcome. The
Swiss researchers do not tell us what they expected
before commencing the study. But let us suppose that we
wish to replicate their study. We might expect 50% of
subjects to die within 5 years, and that adjuvant therapy
will cause the risk of death to be reduced by one quarter,
to 37.5%.
In any comparative study, there is a risk of making a
type I error (claiming the new intervention makes a dif-
ference, when it fact it does not) or a type II error (con-
cluding the new intervention makes no difference, when
in fact it does benefit to the degree initially thought). We
would like to avoid making such errors, but the proba-
bility of making such errors can only be diminished by
increasing the sample size. In fact it is standard to set the
probability of a type I error (called a) at 5%, and the prob-
ability of a type II error (called (3) at either 10% or 20%. If
p is 10%, the power of the study is 90%. The power is the
probability of demonstrating a true difference of the
specified magnitude.
Using tables provided by Machin et al (1997), we would
need 329 subjects in each group (658 in all) to have 90%
449
45
GENERAL CONSIDERATIONS
power to demonstrate this sort of effect as statistically
significant at the 5% level.
several variables on survival (e.g. age, gender, stage of
disease).
PROGNOSIS
1. Studies that outline the natural history of a disease
are useful to gauge how worthwhile the application of
treatment is. A relative risk reduction of 30% may be
useful for someone at high risk, but less so for someone
who is already at low risk.
2. Surgical studies frequently follow patients from the
date of operation until some event such as death, or recur-
rence of a tumour. The resulting data can then be used to
produce a Kaplan-Meier survival curve.
3. Not all patients will reach the endpoint within the
time of the study. These are known as censored observa-
tions. They contribute to construction of the survival
curve until the time of censoring.
4. The Swiss study shows a survival curve for each
treatment group. However, the survival curve for the
control group in a clinical trial may not always give a real-
istic estimate of prognosis. Those selected for a trial may
be selectively fitter than average members of this popu-
lation of patients. It is sometimes asserted that many
aspects of medical care given to patients in a trial is su-
perior to that given to other patients. A realistic survival
curve will be obtained using an observational rather than
an experimental study.
Points to consider when reading the
literature
1. Inclusion criteria and selection of patients should be
carefully documented. They should be assembled at a
common, well-defined point in the course of their disease.
The outcome should also be well defined and established
by a standard methodology.
2. Assembling a cohort retrospectively is fraught with
difficulty. Applying a clear selection criterion may be
impossible. In addition, data may be unavailable for some
or all of those who have died, thus producing a biased
sample. In a prospective study, these questions may be
tackled from the start. Prospective studies are likely to be
expensive and take a long time to carry out if a long
follow-up is required.
3. Subgroups within a cohort may have different prog-
noses (e.g. males versus females, older versus younger
patients, stage I disease versus stage II versus stage III
versus stage IV, etc.). Kaplan-Meier survival curves may
be drawn for the whole group, or for a series of sub-
groups. Comparisons of survival curves between sub-
groups are carried out using the Tog-rank test'. Cox
models are used to assess simultaneously the effect of
SYSTEMATIC REVIEWS/
META-ANALYSIS
1 . The last decade has seen an explosion of interest in
formal syntheses of research studies. It was recognized
that single studies did not in themselves provide defini-
tive answers to clinically important questions, and that
bringing together several results was potentially power-
ful. Systematic reviews, however, differed crucially from
the old-fashioned medical review, in that relevant studies
were searched in a comprehensive and explicit manner,
thus reducing potential charges of bias. Published sys-
tematic reviews will outline exactly which databases were
searched, and which key words were used, so that the
methods could be reproduced by the interested reader.
Inclusion and exclusion criteria will be specified.
2. Once relevant studies have been located, they may
be appraised by the reviewers. Those studies whose
methodology is particularly poor may be omitted from
further consideration. Again, explicit criteria for decisions
made will be described.
3. Provided the data are provided in a compatible way
in the studies concerned, it will then be possible to pool
their results using a technique known as 'meta-analysis'.
The confidence intervals from a pooled analysis will be
narrower (i.e. more precise) than from any single study
included.
4. The major drawback concerns the possibility of
publication bias. Using electronic databases such as
MEDLINE, one might reliably identify all published
studies, but what of those studies which are never pub-
lished? Many researchers embark on studies but never
have them published, either because they are rejected by
journal editors, or, more commonly, because they are
never even submitted. It has been demonstrated empiri-
cally that published studies are more likely than unpub-
lished studies to contain statistically significant results.
Thus the published studies are biased towards showing a
new treatment in a more exciting light than is strictly true.
A famous example concerned the use of magnesium after
myocardial infarction; many small trials had indicated a
possible benefit, but a large trial demonstrated that this
treatment was in fact useless, or even slightly harmful!
5. Publication bias, as defined above, tends to be
particularly strong for small studies. Large studies, even
if statistically non-significant, have a reasonable chance of
being published, but this does not happen for small
studies.
For this reason, systematic reviewers often attempt to
locate unpublished studies and include them in their
450
STATISTICAL CONCEPTS: A TOOL FOR EVIDENCE-BASED PRACTICE
meta-analysis. Writing to experts in the field, and scan-
ning abstract lists of conferences, are methods that have
been used to some effect.
Example: Graduated compression stockings
in the prevention of postoperative venous
thromboembolism
Wells et al (1994) searched for articles on graduated com-
pression stockings (GCS). They used MEDLINE, and also
the bibliography of all retrieved articles. They searched
Current Contents to find new reports that might not have
yet appeared on MEDLINE. They found 122 articles, but
only 35 referred to randomized trials. These articles were
assessed by at least two authors. Some were deemed
inadequate in their method of randomization, others did
not contain an untreated control group, while others used
inadequate diagnostic methods. In all, 12 studies were
judged eligible for inclusion in a meta-analysis. Eleven of
the studies were carried out in moderate risk, non-
orthopaedic surgical procedures, including a total of 1752
patients. It was estimated that the use of GCS led to a
relative risk reduction of about two-thirds.
This systematic review was itself later appraised by the
Centre for Reviews and Dissemination, University of
York. It was felt that the authors' insistence on use of
studies with adequate forms of random allocation meant
that the conclusions of the review were robust. However,
it was pointed out that the authors had made no attempt
to identify unpublished studies, thus leaving open the
possibility of publication bias (see above).
The Cochrane Library now contains a more up-to-date
and thorough systematic review on this subject, last
updated in 1999 by Amaragiri and Lees. They found 16
randomized controlled trials, including some not identi-
fied by Wells and coworkers. This was partly because
some trials were published after the Wells group carried
out their review, but these authors searched EMBASE (an
electronic database with good access to articles not pub-
lished in English) and the Cochrane Controlled Trials
Register, in addition to an ever more comprehensive
MEDLINE. They also hand-searched relevant medical
journals. Finally, in order to address the possibility of
publication bias, they contacted companies that manu-
factured stockings.
In fact, Amaragiri and Lees do not mention finding
unpublished trials. But at least they made efforts, and the
results of their meta-analysis revealed essentially similar
conclusions to those of Wells and coworkers. They
divided their 16 trials into nine where patients were not
undergoing any other form of venous thromboprophyl-
axis, and seven where all patients underwent another
prophylactic intervention. The results for the former
category are shown in a 'forest plot' (Fig. 45.3).
Fig. 45.3 Forest plot.
451
45
GENERAL CONSIDERATIONS
A square is shown to denote the results of each individ-
ual trial. In most forest plots, we are hoping to see squares
(representing the estimated treatment effect) to the left-
hand side of vertical line representing the value 1. This is
because stockings are supposed to reduce the risk of DVT.
If the evidence was that stockings increased the risk of
DVT, the squares would appear to the right of the value 1 .
The nine squares seen in the diagram are of different
sizes. The larger the square, the more weight that study
carries. Thus the study of Allan carries most weight. This
is mainly because it was based on more patients than any
of the other trials (200). By contrast, the study of Barnes
included only 18 patients, and thus has an appropriately
small square.
Each square carries a horizontal line, and this represents
the 95% confidence interval for the odds ratio. These tend
to be wider for small studies such as that of Barnes. Those
studies whose confidence intervals include the value 1 are
not statistically significant (Barnes, Hui, Tsapogas, Turner,
Turpie). Each of these studies (when taken in isolation) fails
to demonstrate a statistically significant benefit of GCS,
The other four studies (Allan, Holford, Kierkegaard, Scurr)
all demonstrate the benefit of GCS in their own right.
The diamond shape at the bottom represents the result
of meta-analysis. The centre of the diamond demonstrates
the overall odds ratio of 0.32. This is a weighted average
of the nine odds ratios for the individual studies. The
width of the diamond represents the width of the overall
confidence interval, which is narrower than any individ-
ual study's confidence interval. Because it is based on
1205 patients (compared with 200 patients for the biggest
of the individual trials), it is a good deal more precise. The
diamond does not include the value 1, confirming the sta-
tistical significance. Even the most conservative estimate
suggests an odds ratio of 0.45, which still implies the odds
of a DVT will be cut by over one-half if GCS are used.
COMPARATIVE ANALYSIS
You may become bewildered by the array of statistical ter-
minology used when different analyses are carried out.
When reading or writing a paper, descriptive data should
be provided in such a way that the results of statistical
techniques appear credible. The worst sort of statistical
practice is to provide p values in the absence of descrip-
tive data.
Here are a few guidelines as to the use of common
statistical techniques.
• Quantitative variables. Calculate measures of location
(mean, median, mode) and measures of dispersion
(standard deviation, interquartile range), and compare
between two (or more) groups.
Categorical variables. Calculate proportions, or odds.
Summary statistics to compare rates: relative risk
reduction, absolute risk reduction, number needed to
treat (to quantify effect of intervention).
Comparative statistics need confidence intervals. A con-
fidence interval (e.g. for the difference between two
means, or the difference between proportions) puts
limits on the likely size of the effect of intervention.
Hypothesis tests. These test whether the comparative
statistic calculated in a particular study is compatible
with the 'null hypothesis'. Two sample t tests for com-
paring means, chi-squared tests for comparing propor-
tions. Quantitative variables not following a Normal
distribution (e.g. pain scores) may be compared with a
non-parametric test such as a Mann-Whitney U test.
All tests lead to a p value; a measure of strength of
evidence against the null hypothesis.
Summary
• How can knowledge of the accuracy of a
diagnostic test help you to arrive at a firm
diagnosis in an equivocal case?
• What elements of a published randomized
controlled trial are important in advising
choice of treatment?
• What are the potential strengths and
weaknesses of systematic reviews?
• How can you prepare a justifiable answer
to: 'What is my likely outlook'?
References
Amaragiri SV, Lees TA 2002 Elastic compression stockings for
prevention of deep vein thrombosis (Cochrane Review). In:
The Cochrane Library, Issue 2. Update Software, Oxford
Fischer SP, Fox JM, Del Pizzo W, Friedman MJ, Snyder SJ,
Ferkel RD 1991 Accuracy of diagnoses from magnetic
resonance imaging of the knee. Journal of Bone and Joint
Surgery. American Volume 73-A: 2-9
Machin D, Campbell M, Fayers P, Pinol M 1997 Sample size
tables for clinical studies, 2nd edn. Blackwell Science, Oxford
Swiss Group for Clinical Cancer Research 1995 Long-term
results of single course of adjuvant portal chemotherapy for
colorectal cancer Lancet 345: 349-352
Wells PS, Lensing AWA, Hirsh J 1994 Graduated compression
stockings in the prevention of postoperative venous
thromboembolism. Archives of Internal Medicine 154: 67-72
452
STATISTICAL CONCEPTS: A TOOL FOR EVIDENCE-BASED PRACTICE
45
Further reading
Bland M 1995 An introduction to medical statistics, 2nd edn.
Oxford Medical Publications, Oxford
Campbell MJ, Machin D 1999 Medical statistics. A
commonsense approach, 3rd edn. Wiley, Chichester
Egger M, Smith GD, Altman DG (eds) 2001 Systematic reviews
in health care: meta-analysis in context, 2nd edn. BMJ
Publishing Group, London
ACKNOWLEDGEMENTS
The clinical scenario was written by the NHS Research and
Development Centre for Evidence-Based Medicine, Oxford
(accessed at http://cebm.jr2.ox.ac.uk/docs/scenarios/
sgu.html on 9 April 2002)
453
Critical reading of the
literature
R. M. Kirk
w
Objectives
Apply objective measures whenever
possible - but do not rely only on
measurable evidence to the exclusion of
that which is not measurable.
Have self-confidence. Do not accept
received opinions - make up your own
mind.
Recognize that surgery does not stand still.
Keep abreast of advances - do not become
an expert in outdated practices.
Absence of evidence is not evidence of absence.
Not everything that can be counted counts, and not every-
thing that counts can be counted.
Sign on the wall of Albert Einstein's office at
Princeton University
INTRODUCTION
$^2!^?#$$&;t&<>;&!&m
£&$&&M&^!&$k
The two quotations should remind you that nothing is
settled. However hard we try to think logically, we work
in a complex and incompletely understood subject. We
may know the full extent of the human genome but we do
not understand what happens to change the chemical
formula into something that is living. Although we wish
to apply evidence-based disease prevention and treat-
ment, we cannot ignore factors that are not yet amenable
to scientific understanding.
Lord Kelvin, the distinguished physicist and mathe-
matician, implied that only if we can describe a concept
in numbers do we understand it. This may apply in math-
ematics but it is not totally applicable to biological
phenomena. The study of living organisms is not yet suf-
ficiently advanced for it to be described in numbers. In an
attempt to be - or appear to be - scientific, we often
ascribe numbers to phenomena and then treat them as
objective measurements. But they are not. The numbers
have been allocated subjectively, in an analogue fashion.
Different observers may allocate different numbers.
An essential but indefinable characteristic of a good
doctor is common sense. Beware of specious science. It is
remarkable that if something is expressed in a formal,
especially numerical, manner it takes on an appearance of
authority and reliability. You need only read some of the
commercial advertisements to appreciate the way in
which statistics are misused.
You must keep up to date with the literature because the
rate of change is rapid. However, try to obtain good evi-
dence, especially of newly introduced methods. Remember
the statement by Voltaire, 'Use the new treatment while it
still works/ He had identified the powerful placebo effect
of new treatments (Latin placebo = I shall please).
Favour evidence-based practice when it is available.
Reports in prestigious journals are usually more reliable
than those in which the papers are not refereed; however,
no journals are totally reliable and you must make up your
own mind. Remember, though, that investigation of prac-
tice must be narrowed, with exclusion of many of the poss-
ible variables. Your patients rarely present with exactly the
same strictly limited features as those used in the trials.
Key point
Literature (Latin liters - a letter) is not
confined to books and journals but also to
other media. Exploit the many sources of
information that are now available. Remember,
though, to maintain the highest critical
standards because much of the information
available on, for example, the internet has not
been subjected to strict peer review before
being promulgated.
LOGIC OF SCIENCE
1. Advances in science occur in a multiplicity of ways.
We should all feel capable of making them, or recognizing
454
CRITICAL READING OF THE LITERATURE
f 46
them if we encounter them. Do not dismiss the un-
expected. Louis Pasteur stated, "Dans Ie champs de
1' observation, le hasard ne favorise que les esprits
prepares' (In the field of observation, chance favours only
the prepared mind).
2. Advances are often made as a result of encountered
problems. Do not put aside problems that have so far
resisted solution. There may be unique features that
throw light on an individual unsolved problem.
Consider discussing it with colleagues; we all view
information differently, and someone may have a
sudden idea that triggers a solution or a possible method
of tackling it.
3. You may develop a possible reason or explanation for
a phenomenon. This is a hypothesis (Greek hypo = under +
thesis = placing; a supposition) or theory (Greek theoreein =
to view; an idea that has not yet been proven). Your natural
instinct is to attempt to prove it. The recommendation of
the great scientific philosopher Sir Karl Popper (1902-1994)
is that you should, on the contrary, try to disprove your
supposition. If you fail, you may determine to use it for the
time being. If you disprove your initial belief, this may lead
you to develop an alternative that may be more robust.
Popper declared that you can never prove a theory but you
can disprove it. He used as an example the colour of swans:
if every swan that you see is white, you can never prove
that all swans are white, because you can never see every
swan that exists, has ever existed, or will in the future exist.
However, you need to see but a single black swan to
disprove it - and of course you can see many black swans
on the Freemantle River in Western Australia.
Key point
We all pay lip service to Popper's logic. How
many times have you seen a scientific paper
that conforms to his teaching?
ORGANIZING YOUR READING
^S^K'^i-^^
1. There is insufficient time to read every paper on
your subjects of interest. You must be selective.
2. A valuable first step is to identify the journals that
will form your core list. You should choose one or more
general scientific journals that may have items of great
promise in your field - Nature, Science, New Scientist. Each
week, quickly scan the contents list.
3. Identify the authoritative journals dealing with your
speciality and be prepared to scan through them.
4. You may read the titles of some articles, the
summary of a few, the summary and selected parts of one
or two, and occasionally the whole article. Rarely, read the
article with obsessive critical attention.
CRITICAL READING
1. Some papers state a monumentally important
advance in a short report. A classic example was the letter
in Nature written by James Watson and Francis Crick
announcing the construction of the DNA molecule.
2. More frequently, the idea has a less immediate
impact and must be presented within a conventional
format. Take advantage of the standard presentation.
3. The Title should clearly convey to you what the
content is. It should convey the key words that allow it to
be traced. Is it relevant to your interest?
4. The Summary must encapsulate the whole article.
When you read it, you should know in outline a simple
answer to each of the main questions posed by and
answered in a paper reporting, for example, an investi-
gation stimulated by a question or a hypothesis.
5. The Introduction answers the first question, 'Why did
we do it?' You should be able to understand clearly what
was the starting point, what has generated the need for an
investigation and what is the question that was asked. Do
you think the authors started with the correct premise?
6. The Method section must state clearly, 'What we did/
It must explicitly reveal every detail of how the investi-
gation was organized, carried out and measured. Has the
method been fully and openly described?
7. The Results answer, "What we found/ All the results
must be clearly displayed. Any inconsistencies should be
identified and explained. Do you understand them, are
they justifiable?
8. The Discussion states "What it means/ This is often
the shoddiest part of scientific papers. Until now the
authors should have provided clear, simple facts. They
should now limit themselves to stating how their results
fit into or alter the position from the starting point. They
may briefly suggest possible supplementary investiga-
tions that they or others could pursue to test the evidence.
Are they overinterpreting their findings beyond the justi-
fiable results of the investigation?
9. The Conclusions should not be a mere repeat of the
summary but clearly and briefly summarize what has
been added to our knowledge by the investigation.
Key point
• Apply your most important asset to the
conclusions - your common sense. Are you
convinced?
455
46
GENERAL CONSIDERATIONS
WHAT DIP Y OU LEARN?
1 . Most importantly, you practice making up your own
mind about the 'facts' that are presented to you on the
basis of the evidence placed before you. You are not just
a passive acceptor of the opinion of others. This gives you
confidence to reject evidence you consider unreliable, and
faith in your own good sense, rather than relying
unthinkingly on 'experts/
2. You may not know the fine points of statistics (see
Ch. 45) but you can decide whether they have been
applied correctly and with integrity. When two groups
are compared/ we may be assured that they differ in one
respect only, but this is never so. Biological variation is so
great and capricious that too much cannot be read into
small differences.
PI
I | Key points
• If you are studying a prospective trial of, for
example, two treatments, are you convinced
that the authors had open minds beforehand -
or were they hoping to prove one method
superior?
• Make sure, when comparisons are made
between groups of patients, that 'apples' are
not compared with 'pears'. The groups must be
closely comparable.
3. You may detect imperfections in the manner in
which two populations are to be compared, that are not
clearly stated. Sometimes aspects such as the method of
clinical follow-up is not clear; for example, was it by
independent assessors, by personal interview or exami-
nation, prospective, performed blindly - when the as-
sessor does not know the treatment or procedure to
which the patients were subjected? Follow-up times may
be given in a general way that does not make it clear that
most of them were made too short, with very few long
term follow-up times. Graphs and histograms may be
used to avoid giving individual figures, in the same
manner that advertisers use them to promote their
goods.
4. Are the claimed benefits of one treatment over
another genuine? There are so many variables: among
diseases, such as site, extent, involvement of vital struc-
tures, virulence; among patients, such as age, sex, comor-
bidity; as a result of diagnosis, early, late, confidently or
uncertainly; institution of treatment, promptly, effec-
tively, long enough; and any ancillary treatment.
5. In cancer treatment, an improved method of detec-
tion may appear to produce improved results in two
ways. Survival times may lengthen because the new
method allows earlier detection, lengthening the
recurrence-free time. The apparent improvement is the
result of the 'lead time', the interval that transpired
between the time of pick-up with the improved method,
compared with later detection. In addition, the improved
method may show that the disease is more extensive than
would be shown by previous methods so that the earlier
likelihood of recurrence is recognized. As a result the
'stage' is raised, whereas less effective methods may result
in the tumour being classified as a lower grade. For
example, when staging of breast cancer is limited to clin-
ical assessment, a tumour may be diagnosed as stage I;
imaging scans may demonstrate local, impalpable glands
so that the tumour is classified in a higher stage, with a
poorer prognosis. Chest X-ray may demonstrate,
however, that rib metastases are present and the tumour
must therefore be placed in stage IV - evidence of metas-
tases. A series diagnosed by clinical examination alone
and placed in stage I thus contains more advanced
tumours and the results of treatment appears poor. If the
tumours have been investigated with modern tests, these
advanced tumours would be classified as stage II, III or IV,
leaving only 'true' stage I tumours. Treatment of this
smaller number produces better results than a mixture of
early and undetected later tumours. This is often called
the Will Roger's effect. (Will Rogers, an American homely
sage, despised Californians. He described the often-
despised (as mentally low grade) Oklahama farmers who
were forced to migrate to California during the 1920s
drought - 'thus raising the IQ in both States/)
6. It is often accepted that authors provide only evi-
dence that supports their hypothesis and those contra-
dictory points that can be demolished. Seek out unstated
weaknesses.
7. Papers sometimes appear too perfect. Were there no
patients lost to follow up, people who did not fully
comply with an arduous treatment regimen, tests in some
that were equivocal?
8. Read other investigations in the same field of inter-
est. You will be surprised that very often the results are
not comparable. You may wonder how this can be: the
populations may differ; among many other reasons, the
expertise, case selection, and familiarity with the condi-
tion and the treatment methods may differ.
9. Why not just read authoritative reviews? Reviews
are written by experts who already have a point of view.
However honest and good intentioned they are, they
inevitably argue for their own views — they would not
adhere to them if they did not believe in them. If you read
a review, seek out one that gives an opposing view.
10. During your career you are likely to see patients with
unusual, perhaps unique, conditions. If you retain your
inquisitive and critical enthusiasm you may recognize
456
CRITICAL READING OF THE LITERATURE
what may be an important advance. Your familiarity with
the literature will have nourished your thinking and
writing abilities, allowing you to report your findings to
your colleagues.
AVAILABILITY OF INFORMATION
1 . We now have available a wealth of publications. In
the past the Index Medicus - often called the greatest
American contribution to medical science - was the
'browser' we consulted to find articles not in the journals
to which we had normal access. We would then write for
reprints of important articles.
2. Through the internet we now have available
MEDLINE; many titles are accompanied by summaries.
Other sources may provide access to the full text. Using
the well-known search engines you can find an immense
amount of information; remember, though, that you do
not know the provenance of many reports that have not
been subjected to independent review. However, you can
find easily understood explanations of difficult subjects
that give you a grasp of them, when the scientific papers
assume you must be familiar with the terms used.
3. A list of available sources soon becomes outdated.
Keep abreast of the advances and of the flow of new
discoveries.
Summary
• Do you acknowledge how important it is
that you do not fall behind and practise
outdated medicine and surgery?
• Will you retain your critical faculties?
However eminent the authors, or
prestigious the journal, your common
sense is your best protection against being
misled by what you read.
• Since few of us try to falsify our
hypotheses, will you determine always to
read opposing articles after reading a
seemingly convincing report?
457
Communication skills
R. M. Kirk, V. M. Macau lay
Objectives
• Good communication is essential in all
areas of activity, not just in relation to
patients.
• Recognize non-verbal as well as verbal
communication.
• Empathize with the listener, especially
when giving bad news.
contrast, the tone of voice, the emphasis placed on certain
words and the reaction to the listener's responses help to
guide the speaker to know how to proceed and estimate
the effect of the words.
Telephone conversations are midway, containing vocal
overtones but lacking the non-verbal expression and
gestures that add a layer of meaning to the words.
It is self-evident that if you wish to communicate with
someone over an important or delicate matter, you should
always choose to do so face to face.
'Communication skills' sounds like yet another facility to
be learned, like operating; however, most of us already
have inbred and acquired competence, as it pervades our
contact with all other people.
VERBAL COMMUNICATION
^^v&^^
^M^&sf&iv&'XH
The words we use, the tone of voice, the speed with which
we speak, the pauses that we interject, all have an effect
on the listener. If we are giving similar information to two
different people, we usually do not attempt to employ the
same words to each of them. Some people adopt the word
patterns of those to whom they are speaking; others,
wishing to impress, may use abstruse or jargon words or
acronyms (words formed from the initial letters of other
words).
The tone of voice and rhythm add a layer of meaning.
Terse, staccato speech is sometimes commanding or
threatening or signifies tension in the speaker. Quietly
spoken words may be soothing or, if given in a sibilant
(hissing) manner, may suggest potential threats.
Face to face communication is much richer than
writing. Words have defined meanings and the writer is
limited to choosing the ones nearest to the intended
meaning plus a few symbols such as exclamation and
question marks or underlining. The writer has to guess at
the response to the message and cannot modify it if the
receiver reacts unexpectedly. The words do not have to be
cast on tablets of stone to be irrevocable in their effect. In
NON-VERBAL COMMUNICATION
This is a very deeply ingrained way of informing others
of our mood and intentions. Our dress may indicate that
we are relaxed and informal, or we may wish it to
register professionalism and formality. Posture indicates
depression and humility or confidence and command.
Most revealing are our facial expressions. The giving out
of signals and the reading of them is often unconscious.
Most of us acquire a social awareness of non-verbal
communication. When one person is speaking and the lis-
tener wishes to interject a remark, he or she signals the
wish or intention, perhaps by a movement to attract the
speaker's attention, a raising of the hand, a seeking of eye
contact with the speaker. The speaker responds, some-
times by returning the eye contact, by smiling and bring-
ing the statement to a close, or resists by raising a hand
with palm towards the person wishing to speak or raising
the voice, to indicate resistance to stopping. The giving
and receiving of signals can be confused and confusing.
A smile and a sneer are not dissimilar - indeed one may
change into the other. A gentle touch is a subtle method
of conveying sympathy, a firm grip can convey authority
and trust, but a push or a blow are threatening.
Actors, salesmen and confidence tricksters have always
recognized, sometimes instinctively, the fundamentals of
what is often called 'body language'. In recent years, non-
verbal communication has been studied and brought to
notice by those claiming to advise salespeople, job appli-
cants, interviewers and 'interviewees/
458
COMMUNICATION SKILLS
47
Key point
Strenuously avoid giving potentially upsetting
news, complaining or arguing, by letter or
telephone. You need to watch the reaction of
your listener to what you have just said, so
that you can, if necessary, modify what you
will next say.
COMf^
1. Remember that you are familiar with clinical sur-
roundings but patients associate them with anxiety and
sometimes with dread. They may be apprehensive, con-
fused or yearning for reassurance that all is well.
2. Because most patients are in later adult life, and
often, therefore, more conventional, they may expect
that doctors who dress and behave reasonably formally,
take their responsibilities seriously. Immediate and
casual use of first names is not welcomed by many older
patients. Similarly, casual exposure of their bodies and
clinical features is resented. We owe it to them to respect
their wishes if we are to obtain their cooperation and
trust.
3. Note that some colleagues adopt a serious and grave
manner, others try to appear cheerful and light-hearted.
There is no standard pattern. Sometimes we are serious
with one patient and jovial with another. Avoid attitudes
and speech that denote overbearing and curt superiority,
or the overcasual 'jokeyness' that may suggest we take the
patient's problems light-heartedly.
4. When you wish to discuss important information
with a patient, ensure that the surroundings are quiet and
that you will not be disturbed or distracted. Hand your
'bleep' to someone who can answer it for you. In appro-
priate circumstances suggest that a relative or friend of
the patient is present.
5. The information you give the patient should be
known to your medical and nursing colleagues, and to
other paramedical carers. In many circumstances it is
valuable for them to be present so they can participate in
the discussion and know what has been decided. Patients'
confidence is eroded if different people give them con-
flicting information.
Key point
Patients you see are already apprehensive. Do
not increase their insecurity by placing them in
undignified circumstances.
Questioning
1. When taking a medical history (see Ch. 3), allow
patients time to speak. Do not make them feel that what
they have to say is of little account. If they are stuck for
words, allow them time to choose a suitable one; do not
immediately feed one that fits your prejudice. However,
you must control the interview, so your timing when inter-
jecting a question for clarification, or asking a new question,
must be sensitively judged. A too rapid interruption cuts off
the patient's train of thought, but if too long delayed it may
allow the patient to take a new, diverting, train of thought.
2. Choose words suited to the patient before you. A
simple person needs simple language spoken slowly, and
repeated or rephrased without signs of impatience. For
example, ask one person where is the pain in the belly if
that was the term he or she employed to you. A pro-
fessional person may resent the avoidance of the more
formal 'abdomen'.
3. The ability to communicate is severely tested if the
patient is a young child, deaf, has a speech defect, a
behavioural anomaly, or has difficulty with the language.
When talking to a person who is hard of hearing, always
sit face to face. It can be impossible to communicate
rationally with those under the influence of alcohol or
other drugs, with people who are hysterical or violent, or
with those suffering from diminished consciousness,
whether it is the result of injury or disease.
Key point
• If you have difficulty in communicating, consider
whether you need help from a senior colleague
or an interpreter, or should you defer action if
the patient's cooperation is likely to return later?
Telling and discussing
1. First find out what is already known, what that
information signifies to the patient, and decide how the
additional information should be presented. As a rule it
is best to start by asking questions such as, 'Would you
like to talk about the [problem]? I am not sure how much
you know.' Later, you may ask questions in order to
evaluate the patient's appreciation of the additional
information you have given.
2. In most circumstances do not try to say too much all
at once. Give the patient time to absorb what has already
been said and wait for an indication of readiness to con-
tinue. From time to time ask questions to check that the
patient really understands what has passed between
you, for example, 'Can you tell me then, how you see the
situation?"
459
47 1
GENERAL CONSIDERATIONS
3. Especially when discussing important problems, be
extremely sensitive to the listener's reactions and signals.
In some cases it may be better to defer the interview to a
later date to allow the patient to absorb and react to what
has already been said.
4. Patients anticipating bad news frequently demon-
strate by their body language, or by suddenly ceasing to
ask questions, that they do not wish to be told anything
more at present. Do not ignore it. Allow the patient time
to absorb what has passed between you and come back
later. Before you restart further discussion, reassess the
patient's comprehension of the situation; you may be sur-
prised at the 'adjustments' made to the information so the
patient can cope with it.
5. Remember that distress, anxiety or despair may be
dealt with by total rejection, blame directed at others or
at you, threatening behaviour or aggression. Do not react
antagonistically.
• Do not contradict or respond to aggressive
behaviour. Stay calm, do not interrupt, be
willing to listen.
Relatives
1. Relatives deserve the same consideration that we
give to patients. We hope that they will give encourage-
ment, support and help to the patient throughout the
management of the condition requiring treatment.
2. Occasionally there is conflict between the demands
of the patient and those of the relatives. What do you say
if a patient demands that you do not disclose what is
happening, while the relatives press you for information?
Your contract is with the patient and you must honour
that relationship. The relatives may ask you not to give
certain information to the patient. Again, judge for your-
self the best course, on the patient's behalf.
Advising
1. Discuss with patients what options are available,
what are the advantages and disadvantages of each. This
is not always easy to do, as not many treatment choices
can be scientifically justified. In biology there are few
areas that are either black or white; most are shades of
grey. This explains the differing advice that patients
receive when they ask for a second opinion.
2. Surgeons have a reputation for being decisive, and
in practice most of us are in no doubt about the advice we
wish to give. Our advice is based on our professional
experience - what we have encountered, read about and
talked about. The patient needs to be encouraged to ask
questions and, when there is no urgency, to go away,
think about the advice, come back and discuss it again.
However, we believe it is a rejection of professional
responsibility merely to lay before our patients the pros
and cons of each course of management and leave it to
them to decide which one to follow. Patients are often not
in a suitable state of mind to make the best decision, espe-
cially if they have just been told that they are suffering
from a serious condition. Therefore, we should end with,
'So in my opinion . . .' Of course, patients are free to reject
the suggested course of action.
F^
Key points
Anticipate aggression from an angry or
threatening patient - but do not behave like a
'victim'.
COLLEAGUES
1. A vital professional duty is to inform colleagues
about matters of patient care. Always write up notes,
avoiding abbreviations, jargon and opinionated remarks
that might be misinterpreted. Sign and date them. When
you hand over before you go off duty, inform the on-call
doctor personally of any outstanding problems.
2. If you have had a discussion with a patient about the
future, or about treatment, ensure that you tell the nurses
and your seniors. There is nothing that undermines the
confidence of patients more than being given different
information by different people.
3. Your colleagues include all those with whom you
come into professional contact: doctors of all grades,
students, nurses, physiotherapists, technicians, managers,
clerical staff, porters, cleaners and tradesmen. Do not
draw a line of 'importance', below which you do not
acknowledge people, or bolster your dignity by trying to
diminish others. Each of us counts as just one.
4. One of the most important qualities we have is our
self-esteem. When we fail to carry out a task conscien-
tiously we expect to be reprimanded. When we perform
well, we rightly hope to be congratulated. If you expect
to be acknowledged, remember there are others that hope
you will acknowledge and encourage them.
IMPARTING BAD NEWS
1. Communicating with ill or distressed people
requires great sensitivity. Your behaviour should
460
COMMUNICATION SKILLS
47
be influenced by your feelings of sympathy and
compassion. Our reactions may be modified if we are
able to enter our patient's personality in our imagination
and think how we would feel if we were in a similar
situation; this is termed empathy (Greek em = in + pathos
~ feeling, suffering). Obviously we cannot always
achieve this, but in making the effort we can identify the
likely reactions and apprehension of the patient and
respond sensitively.
2. We have the duty to keep our patients and any close
relatives informed of what is happening, and what it
means. Of course, we must be guided by the patient's
wishes about what we tell the relatives. This often entails
telling them that recovery is failing, the patient has devel-
oped a complication, or our investigations reveal severe
and perhaps terminal disease. At times of crisis you may
be the only doctor present and are therefore responsible
for dealing with the problem.
3. Prepare yourself before disclosing that the patient
has a potential or actual terminal illness such as advanced
cancer. Review the options by recalling or looking up the
published results of the various choices before you go in
to talk to the patient (see Ch. 39).
4. Ensure that this consultation takes place in a calm
and private area. Ask someone to take over your 'bleep',
so you cannot be interrupted. It is usually valuable to
have a nurse with you so that she or he can tell colleagues
what has been said.
5. As you approach, look at the faces of the patient and
family, and try to judge how they are feeling. You are also
being carefully studied in return, for hints of what you are
about to say.
6. You should be prepared to structure the conversa-
tion. A suggested plan is as follows:
a. Ask the patient and the family what they under-
stand of the situation.
b. Describe the situation as you see it, using terms with
which they are familiar.
c. Outline what can be done.
At each stage you should allow the patient to ask
questions so that you can explain the implications in a
manner and speed that does not distress or confuse the
patient. Be as optimistic as realistically feasible given the
situation; if the outlook is poor, do not unthinkingly
deliver the full extent in one encounter. Explain the
reasons for recommending each aspect of the treatment,
but if the results of trials are poor, you do not need to
volunteer them unless the patient wishes to know them.
Remember that the patient will be trying to come to terms
with the diagnosis and may not be in the best frame of
mind to absorb the consequences and make decisions
about the practical implications. It may be necessary to
defer making an important management decision until
the patient has had time to assimilate information given
during the first consultation.
7. It is sometimes stated that information belongs to
the patient and the doctor has no right to withhold it.
Indeed many patients are very knowledgeable, ask direct
questions, and may wish to be told everything that is
known about the situation and the consequences. Be
aware that this will not apply to every patient, and you
should not dismiss the minority who do not wish to be
told the whole truth, by forcing information on them
immediately. Occasionally a very anxious patient blurts
out the words, T want to know everything', but their eyes
are begging for reassurance that all is well. Be sensitive
to verbal and non-verbal cues from the patient and rela-
tives, and be ready to defer answering questions that are
not asked.
8. In human relations we must retain a sense of balance
and sensitivity. Rigid blanket rules are inappropriate. Just
as in our personal life we try to avoid pouring out sensi-
tive bad news, so we need to be as considerate to our
patients and allow them to dictate the way in which we
inform them. Our duty is to interpret the patient's often
unspoken signals and be governed by them.
Key point
• The founder of the hospice movement in
Britain, Dame Cecily Saunders, stated: 'The
patient, not the doctor, or the nurse, or the
relative, must retain control of information to
suit his needs.'
9. Provided you are sympathetic and sensitive, you are
unlikely to make gross mistakes. Those who are told very
serious news, and are later asked what was said, often
give a different and more optimistic version if they are
unable to cope with the full truth. There are some
patients who indicate that they fully understand the cir-
cumstances but do not wish to have them spelled out in
concrete terms. Respect their wishes.
10. Never leave a patient without hope or support. If
treatment such as operation cannot be employed, it is
possible to say, 'Operation is not appropriate but I shall
continue to care for you/
11. Remember that the news may be more distressing
for the relatives and friends than for the patient, because
they are not only sad for the patient but they are desolate
at the prospect of being left alone. However, the informa-
tion belongs to the patient, not the relatives. Ensure that
you do not disclose anything to them against the patient's
wishes.
461
47
GENERAL CONSIDERATIONS
Key point
Now write in the notes exactly what has passed
between you and inform your colleagues
including the family doctor and the nurses.
1. The outcome of any form of medical care does not
always reach expectations. You cannot anticipate and warn
the patient and relatives about every possible complication.
2. Every person makes mistakes from time to time by
failing to notice a complicating factor, by misjudging a
complex situation, by making the wrong decision or by
technical error.
3. Do not attempt to hide the fact from a patient if
something has gone wrong. Explain it and say what
measures you will take to put it right. Just as we detect
evasiveness when we watch a politician being asked an
awkward question on the television screen, so our
patients instinctively recognize any reluctance on our part
to explain a misadventure.
4. One of the commonest complaints of patients is that
when things go wrong, sympathy and openness are with-
held. They naturally become suspicious.
Key point
Telling a patient that you are sorry if an
unexpected complication occurs, is not an
admission of guilt.
Summary
• Do you appreciate that there are no rigid
or absolute rules except to be sensitive to
the patient's signals?
• Do you recognize that communication is
more than mere words?
• Will you remember to give patients time
to absorb your remarks, and time to
respond in their own way?
• As you prepare to give patients
information, will you first enquire how
much they already know?
• Do you accept the need to recognize and
honour the (often non-verbal) signs that
patients do not wish to have more
information forced on them at this time?
• Will you remember to keep your
colleagues informed about the
information passed between you and the
patients?
• Do you recongize the danger of trying to
conceal complications and errors from the
patients?
Further reading
Buckman R 1992 How to break bad news. Papermac, London
Lloyd M, Bor R 1996 Communication skills for medicine.
Churchill Livingstone, Edinburgh
Myerscough PR 1992 Talking with patients. Oxford University
Press, Oxford
462
The surgical logbook
D. M. Baker
Objectives
• Understand the importance of maintaining
a logbook.
• Understand how and what information to
collect in your logbook.
• Know how to analyse the collected data.
• Recognize the difficulties in keeping a
logbook.
|NTR0HDUCTION
A surgical logbook is a record of the activity you have
undertaken. Although important during training, it
remains a central part of the routine throughout your
career. Of the different parts of a surgeon's job, the easiest
to record are:
• Operations performed
• Patients seen in clinic
« Patients admitted and seen while in hospital.
I shall concentrate on logging actual operations under-
taken. Although this is the most commonly kept record,
the other two records are important, as you will see and
treat many more patients than those operated upon. The
outcome of surgical patients treated conservatively is as
important as the outcome of those operated on.
WHY KEEP A LOGBOOK?
1 . Just as airline pilots keep a log of every flight they
make, so it is your duty and self-discipline to keep a
record of the procedures you have performed. Although
not yet legally demanded, you are required by the
Surgical Colleges to keep a logbook during training. This
is to demonstrate that you have been adequately trained
in an operation or procedure before being considered fit
to undertake it independently. It will soon be necessary to
demonstrate that, as consultant surgeon, you continue to
demonstrate your competency
2. The logbook provides a source of self-auditing sur-
gical practice. If, for example, it demonstrates a series of
wound infections following a particular procedure, you
must identify and rectify this.
3. For you, the trainee, a logbook identifies strengths
and weaknesses in your training. It may demonstrate sig-
nificant experience of one procedure but show deficien-
cies in another At the regular formal appraisal you
should be guided to rectify the deficiency.
4. The logbook helps your trainers assess the standards
within the specific posts of a surgical training rotation. If
your log shows that you have undertaken unsupervised
major procedures at night, this can be investigated to
establish if you are very able, or the trainer should be
informed on the training of surgeons!
COy-ECTINGTHE)N
1 . Spreadsheets are ideal for recording information, or a
grid of data divided into rows and columns. Each oper-
ative procedure occupies a row, with each item of infor-
mation occupying a separate column. There are a number
of choices; the most simple is a lined school exercise book
with vertical lines dividing the pages into rows and
columns. The Royal Surgical Colleges have logbooks, and
computer packages are available, at a range of prices,
that are compatible with personal (PC) and palm-top
computers. The data in computerized logbooks can be
analysed quickly, presenting it clearly and neatly. More
complex spreadsheets provide a full database.
Key point
It is not the logbook's complexity, type or cost
that count but the accuracy and completeness
with which you collect and record the data within
it.
463
48 1
GENERAL CONSIDERATIONS
The operative information collected varies with your
expertise and interest. This will change and develop
throughout your career. However, some core information
is always necessary. This includes:
2. Patient details - record name, age or date of birth, sex
and hospital number as a minimum, otherwise your log
cannot be externally audited (see quality assurance later),
and you may fail to trace the notes, or follow up the patient.
3. Demographic details - complete the columns for
hospital, operation, date and time, whether planned,
emergency or 'next routine list'.
4. Staff involvement - what was your involvement, who
performed the operation, who assisted, who was the most
senior surgeon present? You may record the anaesthetist
and even the scrub nurse - although this is entered in the
hospital records.
5. Operation - devote at least three columns, each more
specialized and specific than the last. Within your training
programme you rotate, so enter the name of the speciality
in the first column, such as orthopaedics or neurosurgery.
In the second column name the subspecialty, for example
within general surgery it may be colorectal or vascular.
Record the name of the procedure in the third column.
The Office of Population Censuses and Survey (OPCS)
have developed specific codes for each operation to
ensure uniformity for accurate subsequent analysis.
6. Anaesthesia - record the type, such as local or
general, as a minimum.
7. Selection of procedures - you may decide what extra
procedures you wish to record, for example, rigid sig-
moidoscopies or central lines you insert.
8. Complications - record details of all adverse events
following operation. Anastomostic leaks, wound infec-
tions and haemorrhage are obvious, but even though
urinary tract infection and deep vein thrombosis may not
be technical complications, record them.
9. Mortality - a perioperative death is one occurring
within 30 days of operation. Record all deaths even
though they may not be related to the procedure
Key point
The only way to avoid complications is not to
operate. Be honest with yourself and record all
complications.
PROBLEMS WITH KEEPING A LOGBOOK
^■^^^^'/^■¥i^^^^^^;^^^:^^'/^
2. Develop a routine. Discipline yourself to complete
the entries in your logbook every time - when you leave
the operating theatre, or every night before going to bed.
If you lag behind it is tempting to give up.
3. Record the data soon after the event while it is still
fresh in your mind. Collect it little by little as you accu-
mulate experience. If you defer it for intervals of once a
month, you will miss patients and fail to remember the
data accurately.
4. Collect your data from original sources, from what
you know to have happened in the operating theatre, not
from the operating room logbook or the hospital com-
puter record of admissions and discharges, as this infor-
mation is not reliably accurate.
5. Include all operations. Do not exclude minor proce-
dures such as excision of sebaceous cysts because you
have undertaken the procedure several times before.
Avoid this temptation or your logbook will become inac-
curate and incomplete.
6. Record all complications, even though it may
demand courage to admit them.
1. Inaccurate and incompletely kept logbooks are a
waste of time. Acquire an enthusiasm for keeping an
accurate record of operative activities.
Key point
Keep your logbook up-to-date, comprehensive
and accurate
7. Analyse the data regularly It is a stimulus to assessing
your progress and identifying your strengths and weak-
nesses. It is both important and gratifying, demonstrating
the value of keeping an accurate, complete logbook.
8. Quality assurance checks ensure that your data col-
lection is accurate. At intervals of approximately 3 months,
check your list of operations against an independent
source such as the operating room logbook. Your record
should be more accurate and complete than any other list,
and if it is not, then your data collection is inadequate.
9. Keeping it legal: register your log book with the data pro-
tection agency. Your logbook must not infringe the patient's
personal rights. You must avoid allowing this information
to become publicly available. Ethical and legal restrictions
on ensuring patient confidentiality apply here, as else-
where in medicine. To ensure this, keep minimal patient
information, such as the initials and not the names or hos-
pital number. This creates difficulty for future audits and
follow-up studies. If you keep your logbook always within
the hospital where you work, it can be registered with the
hospital's list of patient databases. This limits your access,
as you must register it each time you move hospitals and
you cannot take it to your home. If you are creating a sur-
gical log for the whole of your working career, which you
should be, then consider registering it under the Data
464
THE SURGICAL LOGBOOK
48
Protection Act, 1988. You need to fill in a form, obtainable
over the internet (http://www.dpr.gov.uk), and pay an
annual nominal fee.
ANALYSING THE DATA
The logbook contains a vast wealth of information from
which many facts about training and, subsequently,
surgical practice can be drawn. Analysing what you have
done can be an exceptionally informative and often enjoy-
able reflection on your progress. Before starting to analyse
your data, clearly determine what information is needed.
For example, while in training it is important to know the
number of operations you have done, their size, the
degree of urgency and the level of supervision received.
Using the above layout, this information can be extracted
either manually or with the aid of a personal computer.
Problems with data analysis
Analysis takes too long
If the logbook data is stored in a paper book, analysis is
done manually by counting through each case. This will
take time once there are several years of cases. If the log
is stored on a computerized spreadsheet, analysis time is
considerably shortened. However, a limited basic knowl-
edge of computers and computer spreadsheet analysis is
necessary first. This should never be considered a hurdle
and all surgeons in training should be prepared to sacri-
fice the single afternoon required to obtain these skills.
The Colleges offer basic computer skill courses.
Analysis appears incomplete
Assuming complete data collection, a lack of uniformity
between cases in recording similar data may result in a
failure to detect all cases. For example, if abdominal aortic
aneurysm repairs are sometimes recorded as 'aneurysm', at
other times as 'AAA' and yet other times under the OPCS
code LI 940, computer analysis looking only for 'aneurysm'
will miss cases coded with either 'AAA' or LI 940.
The logbook is lost
Always keep at least one recently updated copy of your
logbook separate from the original.
WHAT DATA DOES YOUR HOSPITAL
KEEP?
as a surgeon need to undertake this. However, it is
important at all levels of medicine. NHS trusts collect
data about inpatients, outpatients and others on their
patient administration systems. The data include demo-
graphic details of the patients, dates of admitted care and
clinic appointments, the consultants in charge of their
care, diagnostic and operative procedure codes, and a
variety of other such information.
Trusts routinely send nationally specified subsets of
these data to the NHS-wide clearing service (NWCS),
which then electronically redistributes the information
about patients to the appropriate commissioners of health
care. This enables the local commissioners to monitor the
workload of all the trusts serving large or small numbers
of their patients.
Each quarter, a summary of the inpatient data held by
the NWCS is sent to the Department of Health's own
database, the hospital episode statistics (HES) system. It
is HES that is used for the calculation of published clini-
cal indicators - dubbed 'league tables' by the media - and
for high level planning of the NHS, monitoring its per-
formance and other government purposes.
The Department of Health is intending to add more
detail to the data sets held at NWCS and HES, including
the codes of surgeons and anaesthetists present in theatre
during operations.
CONCLUSIONS
Keeping a record of your surgical activities is a central
part of the discipline of being a surgeon. It requires dedi-
cation to ensure its accuracy and completeness, but if well
done you have a valuable record of your activities as a
surgeon.
^^i^:-^:^ 7 ^^
Data collection is very important in reviewing progress
and planning future changes. On an individual level, you
Summary
• Keeping a record of all surgical activity is
an integral part of a surgeon's job, both
while in training and later in professional
life.
• On every procedure, keep information
relating to the patient's details, the site
and time of the operation, the procedure
undertaken and by whom and,
importantly, record all complications.
• Ensure that the data are collected quickly,
accurately and completely.
• Analyse and review your progress
regularly.
465
The MRCS examin
D. Wilkins
Objectives
To explain the new format of the
examination.
To provide insights into the philosophy
that underpins the examination.
To provide advice on how to approach the
examination.
INTRODW
The MRCS (Membership of the Royal Colleges of
Surgeons) examination was devised and introduced in
1 997 and has since been conducted by all four of the Royal
Colleges of Surgeons of the United Kingdom and Ireland.
Successful completion of the examination, which com-
prises a series of assessments, is designed to mark the end
of basic surgical training by the attainment of a 'satisfac-
tory' standard of knowledge and clinical skills. In essence,
the standard of performance expected is that of an ex-
perienced, well-motivated and able senior house officer
(SHO) who has completed a 2 year rotation through a
series of approved basic surgical training posts. I provide
a broad overview of the regulations for the English
College examination appropriate from September 2002.
Changes in format and sequence will apply to those
taking the clinical section for the first time after May 2002.
You must study those for your preferred College as early
as possible.
What of the philosophy that lies behind the MRCS? The
aims of the examination can be expressed succinctly by
stating that it aims to be fair and thorough. 'Fair' means
that we shall examine to a consistent standard, explicitly
stated as clearly as possible in the examination syllabus
and also in the curriculum. Curriculum (Latin currere = to
run) defines the whole breadth of knowledge and skills to
be acquired during training; the syllabus (Greek sittuba =
book label; programme, abstract) sets out the segments
that will be assessed by the examination. Great care is
taken in all modern examinations to achieve consistency.
The expertise required to achieve this is substantial and is
reflected by the infrastructure necessary to support the
examination and subsequently in the cost of the exam-
ination which, surprisingly runs at a loss! Fair also means
that all candidates will be treated in similar manner
without bias of any kind.
Thoroughness' is the other, as yet unachieved, ambi-
tion of examinations. Ideally, examinations test all areas
of knowledge and skill outlined in the curriculum. The
aim of basic surgical training is to train and educate aspir-
ing young surgeons to a level of 'competence' across a
range of skills. Clearly, an examination set outside the
workplace cannot assess all of these competencies.
Operating skill, attitude and values must be assessed in
the workplace. Factual knowledge, ability to examine a
patient properly and communicate effectively can be
tested reliably in an artificial setting. Overall, the exam-
ination sets a demanding agenda of quality and develop-
ment for the examiners.
The MRCS examination is the main hurdle for aspiring
young surgeons and, during the 5 years since its intro-
duction, it has come to be accepted as a well-conducted,
fair and thorough examination. Basic science is empha-
sized to create an adequate foundation of core scientific
knowledge.
Key points
• The MRCS examination aims to be a fair and
thorough series of assessments.
• It will continue to develop to fulfil the
demands of training and available reliable
methods of assessment.
Requirements (Table 49.1)
1. You must have completed a minimum of 24 months
of training in approved posts. Type 1 posts provide
general experience, Type 2 provide specialist experience
and training. Details are available from the examinations
466
THE MRCS EXAMINATION
49
Table 49.1 Timetable and eligibility for the sections of the MRCS (England)
Section
When held
Where held
Criteria for eligibility
Papers
March and September
London and regional centres
Any time after enrolment
Viva
June and December
Royal College of Surgeons,
A pass in MCQ papers
London
20 months tn approved posts
Communication skills
June and December
Royal College of Surgeons,
A pass in MCQ papers
London
20 months in approved posts
Clinical examination
January and July
Regional centres
22 months in approved posts
A pass in MCQ papers
A pass in the viva section
departments of the respective Royal Colleges and their
web sites.
2. You must have satisfactorily completed an approved
course in basic surgical skills.
3. You may sit the multiple choice question (MCQ)
papers at any time after enrolling with the College, You
may attempt it an unlimited number of times. Once you
pass the MCQs you may take the viva after a minimum
period of 20 months in recognized training posts.
4. Once you have taken the viva for the first time you
must pass this plus the clinical examination within 2 years.
5. You must attain a pass in all sections of the
examination.
6. The MRCS itself will not be awarded until the full
24 months of training have been completed.
Advice
1. Prepare by taking every opportunity to examine
patients thoroughly and confidently (see Ch. 3). Use your
clinical time wisely assiduously acquire new skills, take
every opportunity to practise what you have learned and
be totally committed to your craft.
2. Plan your training to mirror the philosophy of the
examination. Choose your training post carefully to
acquire clinical experience. Choose a committed trainer in
preference to a prestigious one.
3. If possible, work with friends and colleagues at the
same stage, as it is difficult to work in isolation. It may be
convenient to meet up once a week or in the evenings.
Ask your senior colleagues to monitor you, question you,
advise you, criticize you and encourge you.
4. You will benefit from the Advanced Trauma Life
Support (ATLS) and Care of the Critically 111 Surgical
Patient (CCrISP) courses if possible. Progress through to
the clinical examination will only be allowed if the viva is
passed, but the communication skills section may be
retaken separately if failed and will not hold up progress
to the clinicals.
5. On the day of each examination, you will have been
asked to present yourself at a time and a place. Note this
carefully, together with any documents that are required.
Arrive on time; do not fail to allow for heavy traffic or bus
and train delays. Examiners try to be helpful but the
margin for error is extremely slim and if you miss your
appointment slot you may be deferred.
6. If you fail any section, the examiners will have made
notes in order to provide some feedback should you fail
the whole examination. You can obtain this information
through the Examinations Department on request. It is
intended to help you direct your learning towards a more
successful outcome at your next attempt.
ASSESSMENTS, STANDARDS AND
MARKING
1. Formative assessments are designed to aid you and
your trainer. They may involve tests or assessments con-
ducted by your trainer; your performance is then used to
help you and your trainer decide on the requirements for
future training. In other words, they help to 'form' sub-
sequent teaching.
2. Summative assessments are designed to confirm that
a prescribed standard of skill, knowledge and /or compe-
tence has been achieved. The driving test is an example.
Understand that the MRCS falls firmly into the sum-
mative category.
3. A single isolated examination at the end of a sub-
stantial period of training is considered unsatisfactory, as
it is unlikely to provide the necessary range of assess-
ments. More importantly, it is unlikely to stimulate you
to acquire skills and knowledge systematically during
training.
4. A single 'exit' examination also suffers from the
drawback that it gives you no indication of your progress
until the end of the course. This is unhelpful and wastes
energy and resources.
467
49
i ii ■ j ■ ■ i in i n MamijiHtMiiiiMMHii^anniii
GENERAL CONSIDERATIONS
5. The MRCS examination addresses this by providing
a series of assessments during, as well as at the end of,
basic surgical training. These will be further refined and
developed as surgical training evolves in the UK, and
worldwide, within a society that is increasingly prescrip-
tive and regulated.
6. The curriculum for basic surgical training in the UK
is being, and will be, revised, as will the pattern and
assessment of training. The end of training will soon be
marked by the award of a certificate of completion of
basic surgical training (CCBST) but the MRCS examina-
tion will remain the most important assessment to be met
and overcome by you.
7. The pass mark must be set at a fair and appropriate
level, and maintained at a constant level from one
examination to the next. When constructing the question
papers (which incidentally are marked by optical scan-
ning), a series of standard setting exercises is conducted
to agree a cut-off point between pass and fail, under the
direction of an expert. The time-consuming and demand-
ing Angof technique combines the views of a substantial
group of surgeons. Such methods are now a prerequisite
for conducting professional examinations. A panel of
external advisors was established initially and continues
to direct the appropriate technical measures for setting
and maintaining standards.
8. You may wish to know the principles of marking
methods. An aggregate of marks is used to measure per-
formance in an MCQ paper or objective structured clini-
cal examination (OSCE). A check list system is impractical
and inefficient for complex tasks such as clinical exam-
inations: examiners must make judgements. To ensure
consistency, new examiners undergo training. Existing
examiners undergo refresher training and regular
appraisal of their performance during each examination.
Furthermore, each examiner has available a set of estab-
lished criteria to help form that judgement, and at the end
of each interview the examiners mark independently before
conferring, discussing details and agreeing a final mark.
Pass /fail is decided on the combined total of marks across
each section, with some small leeway for adjustment for
borderline candidates resolved at the daily examiners'
meeting.
Key points
• Do you match the knowledge and standards of
a well-motivated, competent, experienced
SHO?
• Do you understand the difference between
summative and formative assessment?
Remember, in the clinical examination you may
be able to compensate a substandard
performance in one bay with a good
performance in another.
OVERVIEW OF THE E^WMN^ION
1. Examiners must make judgements regarding the
emphasis on particular areas of the curriculum. This is
intended to encourage systematic learning and training
so you develop sound insights, knowledge and skills.
Throughout your professional life you need a grasp of the
scientific base for surgical practice. In response to this, the
MCQ papers have been increased to accommodate extra
scientific content. Take every opportunity thereafter to
refresh this knowledge beyond the examination, or it will
decay. Be aware that basic sciences are needed for the
Intercollegiate Board examinations sat during higher
surgical training.
2. The examination is divided into four sections:
a. Multiple choice questions (MCQs)
b. Viva voce (Latin vivere = to live + vocare = to call; oral
testimony)
c. Communication skills test, which takes place on the
same day as the vivas
d. Clinical examination (Greek kline = bed; strictly, by
the bedside).
The vivas, clinical examinations and communication
skills tests are taken towards the end of basic surgical
training and pitched at the standard expected of an ex-
perienced SHO. Until recently, the clinical examination
preceded the vivas. A relatively high failure rate in the
vivas was ascribed to the fact that, following clinical
success, candidates had only 2 weeks to prepare for the
vivas. Clinical examination with bays taking 10 min each
was considered too rushed and was expanded. The vivas
are largely knowledge based. The clinical examinations
are rightly the highest tests of skill, knowledge and deci-
sion making.
THE SECTIONS OF THE EXAMINATION
Multiple choice papers
1. There are two papers, each lasting two and a half
hours. One is held in the morning, the other during the
afternoon. They can be taken together or on separate occa-
sions. The examinations are held twice a year.
2. The papers cover two aspects: 'core' topics - a
knowledge of the basic sciences that underpin surgical
practice; and 'systems' topics - general surgical practice
468
THE MRCS EXAMINATION
49
itself. Both papers aim to test these two key areas. When
the examiners set the papers they place the questions
into one of these two categories, or a third 'mixed'
category that combines both basic sciences and clinical
knowledge.
3. Each paper is divided into two sections. The first
comprises 65 questions that are in the multiple true/ false
format (MTF); the other comprises 60 items that are in the
extended matching (EM) format. MTF questions test a
very basic level of recall of factual knowledge and the
answers are, in effect, a pure memory test. Extended
matching questions require you to match one, more or
none of a series of options with a series of clinical sketches
(vignettes). This format is designed to simulate questions
that may be encountered within genuine clinical situ-
ations, thereby testing your ability to apply knowledge.
This is considered to be a better, or more Valid', assess-
ment (Table 49.2).
Tab
Table 49.2 Example of extended matching
question
Theme: postoperative complications
Options:
a. Tension pneumothorax
b. Unstable angina
c Septicaemia
d. Acute massive pulmonary embolism
8. Myocardial infarction
For each of the dinical vignettes described below,
select the single most likely postoperative
complication from the options listed above. Each
option may be used once, more than once or not at
all.
1 . A man of 75 had emergency surgery for a
perforated diverticulum of the sigmoid colon.
Twenty-four hours after operation he was
peripherally warm, hypotensive (95/40 mmHg), and
oliguric. The ECG was within normal limits.
2. A man of 75 had a hip fracture treated by
hemiarthroplasty. In the history it was apparent
that he had fallen a couple of days before he
presented. He received subcutaneous heparin from
the time of admission. Six days after operation he
became hypotensive (95/75 mmHg) and was blue,
cold and clammy, with a high central venous
pressure. He had inverted T waves in lead III.
3. A man of 75 had a laparoscopic cholecystectomy.
The foUowing day he was noted to be peripherally
cold with a tachycardia. He had crackles at the lung
bases. The ECG showed waves and ST segment
elevation in the chest leads.
Answers: l-c,2-d,3-e
4. There is no negative marking for this or the extended
matching section - marks are not deducted for incorrect
answers. However, effective statistical techniques are
applied to counteract the effects of overselecting choices.
Remember that the papers are marked using optical scan-
ning, so use only pencils of the appropriate grade/ which
are supplied, together with erasers. Sampling is carried
out to check the system for accuracy and the scanner
queries uncertain pencil marks; however, be positive with
your pencil marks and if you wish to erase a mark, do so
thoroughly.
Key points
• Carefully read the glossary and instructions set
out in the front of the papers.
• Read the stems of the questions carefully.
• Do not be tempted to 'random guess' the
answers.
Viva voce section
1. This is a test of your ability to apply both pure and
applied basic sciences to the practice of surgery. There are
three sections, each of which is conducted by at least two
examiners:
a. Applied surgical anatomy and operative surgery. A
specialist takes you through some anatomical questions
that may involve photographs, sketches, a model or a
cadaver. A colleague at the same table questions you on
the surgical application of anatomical knowledge for
operations and other practical procedures, and the prin-
ciples underpinning them. Your logbook may be used as
a guide to your experience for the purposes of framing
questions.
b. Clinical pathology and principles of surgery are exam-
ined at another table. One examiner poses questions on
knowledge of basic pathology, the other questions you on
applied pathology.
c. Applied physiology and critical care. At the final table
an examiner with a specialist interest explores your
knowledge of basic physiology; the surgeon examiner
tests your clinical knowledge on critical care or other
acute clinical situations, also assessing your understand-
ing of the underlying physiological principles.
2. Questions are constructed to provide a uniform
approach. They usually start with a fairly straightforward
lead into the subject so as to focus your mind on the topic.
Subsequent questions progress to the limits of your
knowledge before moving on. You may be taken far
beyond the level set for a pass in order to establish that
469
49
GENERAL CONSIDERATIONS
you have attained an adequate level of knowledge across
a range of topics.
3. The examiners are mostly interested in eliciting what
you know. They provide as much opportunity as possible
for you to display it by covering a range of topics.
Questions are framed carefully and it is vitally important
that the candidate listens and responds to the question
asked rather than obfuscating. Much better to admit that
the answer to a question is not known so that the inter-
view can move on to other, hopefully more productive /
areas rather than leaving awkward silences or filling the
space with irrelevant material.
Key points
• Listen to the questions and respond to them.
• Admit ignorance straightforwardly so that the
examiner can move to another subject.
The clinical examination
1. This tests your ability to examine a patient, elicit the
appropriate physical signs, discuss their significance and
formulate a plan of management. It is conducted simul-
taneously at several centres throughout the UK and you
are allocated as close as possible to, but not usually at,
your own hospital. If you had not taken the clinical exam-
ination for the first time by May 2002, the clinical section
comprises four bays, in each of which you will spend
15 minutes. The bays contain cases categorized as follows:
Bay 1 - Superficial swellings and skin
Bay 2 - Musculoskeletal and neurological conditions
Bay 3 - Circulatory and lymphatic conditions
Bay 4 - Trunk (including thorax).
2. You are briefed as a group by the supervising exam-
iner and a member of the examinations department. You
are then shown to a holding area where the documenta-
tion is checked. Thereafter you are addressed by number
to provide anonymity. Following a roll call you are shep-
herded by examination staff, ready for the bell. When this
sounds you are introduced to a pair of examiners who
take you to the bay for examination.
3. Since time is limited, be prepared to move through
topics and cases fairly rapidly. The examiners are anxious
to test the breadth as well as the depth of your knowledge.
Key points
Listen closely to the instructions you are given.
If you are uncertain, ask for clarification.
• Do not 'short cut' the routine of inspection,
palpation, percussion and auscultation.
4. Be prepared to be asked to tell the examiner what
you are doing, why, what you find and what it means, as
you proceed. Practise doing this beforehand. The clinical
problems tend to be straightforward, so concentrate
initially on common conditions, not rarities.
5. One examiner takes the lead in directing the examin-
ation and the other listens, taking notes.
6. Hand-cleaning facilities are available by the bed or
nearby but avoid wasting examination time.
7. A limited number of stations will be based on the
Objective Structured Clinical Examinations (OSCE)
format. These test your expertise in clinical examination
technique. This has been introduced because some candi-
dates are defective in the correct technique. The format
has not yet been finalized, but it is likely to comprise a
station, lasting 3-5 minutes, where you are required to
perform a task under observation by the examiners. A
typical test is the examination of a joint or another region.
A bell rings to finish the interview. The examiners have
2-3 minutes only to mark you independently, confer, and
agree a final mark, so leave promptly
8. You are ushered from the examination. The super-
vising examiner carries out a short, collective debriefing.
You may then leave.
9. You may be given the option of reattending at the
end of the day to receive your results. If you are success-
ful, there is a short congratulatory ceremony.
Communication skills
1 . This section aims to assess your ability to communi-
cate effectively with a patient or patient's relatives in a
typical clinical situation (see Ch. 47). Until the end of 2002
it focuses on the giving of information; for example,
informing an anxious relative about the condition of the
patient, or providing preoperative information to patients
(see Ch. 14). Subsequently it is intended to pilot a test
of the candidate's ability to extract information from a
patient, analyse it and communicate it to fellow pro-
fessionals. It should provide little difficulty if you have
occupied a busy training post.
2. You may wait in a holding room for a maximum of
three-quarters of an hour as your group is directed, singly,
into the examination cycle. You enter the reading room to
be given a vignette - a short character sketch or word
picture - to read for 5 minutes. It outlines a fairly realistic
clinical situation in which you, as the SHO, are obliged to
interview a relative or patient, assess the situation and com-
municate appropriately. The vignette defines your task.
3. You are now conducted to the interview room and
greeted by the two examiners, who introduce you to the
470
THE MRCS EXAMINATION
'patient' or 'relative' by the role-play name. You are now
in control of the interview. The examiners observe but do
not intervene. The actor stays in character' throughout
and is instructed and coached to behave in a typical
manner in that situation and given an itemized series of
'Points of Concern' to discuss with you. You will find that
the atmosphere rapidly ceases to be artificial.
4. After 10 minutes the interview ends, or before this if
you are satisfied you have covered the concerns satisfac-
torily. The examiners then discuss the interview with you.
5. As yet the format of the new sections is not fixed.
Probably you will take an observed history from a simu-
lated patient, followed by a presentation to the examiners.
You may be asked to prepare a written communication.
The time allotted to testing communication skills is likely
to be at least 40 minutes, reflecting the recognition of their
importance.
2. At present the examinations conducted by the four
Royal Colleges of the UK and Ireland are broadly 'equiv-
alent'. It is hoped that an intercollegiate MRCS can be
developed.
3. The curriculum for basic surgical training for the
English Royal Colleges is intended to integrate in-training
and external assessments, including the MRCS examin-
ation. Comprehensive assessments during basic surgical
training should encourage those with appropriate apti-
tudes and commitment, and discourage those without the
essential traits.
4. It is likely that a certificate of completion of basic
surgical training (CCBST) will be introduced.
5. Modern working practice, for example the European
Working Time Directive, discourages long hours of clini-
cal work. The required study will need to be undertaken
out of defined working time.
Key points
Read the vignette carefully to determine the
task you have been set.
Give the simulated patient accurate
information and behave in a professionally
correct manner.
FUTURE DEVELOPMENTS
1. The MRCS examination will develop in line with
accepted good practice in education and in response to
changes in clinical surgery and assessment techniques.
Summary
• Do you appreciate that facts alone are
insufficient unless they are organized and
produced to the examiners at the right
time?
• Have you practised taking a history,
examining a patient and interpreting your
findings until you are confident in your
clinical skills?
• Is the scope of your knowledge broad
enough and sufficiently up to date?
• Have you fulfilled all the requirements to
sit the examination?
471
The intercollegiate
examinations in surgery
R. E. C. Collins
w
Objectives
Provide an introduction to the intentions
of the examination.
Display the need to obtain current details
of your subspeciality examination.
Outline the conduct of the examination.
This examination is a serious hurdle. Initially it was
considered a mere formality but the first candidates had
received many years of prolonged intensive training. It
demands an understanding of the syllabus, appropriate
reading, and capability to respond to questions at con-
sultant level. You need knowledge of and competence in
the generality of your speciality subject that fit you to be
on emergency call. In addition, you must be fully compe-
tent in your subspeciality interest, in which you might be
the sole representative in your hospital.
INTRODUCTION
The four Royal Colleges of the British Isles have formed
the Intercollegiate Examinations Board. Each of the
Specialist Advisory Committees (SAC) in the nine recog-
nized surgical disciplines have produced their own spe-
cialty examination. The examination has exposed areas of
ignorance in some trainees that are a reflection of sub-
optimal standards of training. The intention is to create a
higher standard of rigorous annual assessment of all
trainees, to identify their deficiencies at an earlier stage
and take corrective action. Meanwhile, there have been
significant changes to basic surgical training. In 2003, the
first candidates who have not taken the Primary FRCS or
Clinical Surgery in General (CSIG) examinations (which
contained a significant element of basic sciences) take the
intercollegiate examinations. Inevitably, the intercolle-
giate examination will evolve to take these changes into
account.
A balance will need to be reached between all-round
surgical competence and the recognition that surgery is
now practised on an increasingly subspecialist basis. In
general surgery, for example, candidates may choose to
have a significant part of their examination devoted to the
subspeciality they intend to pursue. In some subspecial-
ties, such as vascular surgery, pressure exists for an exam-
ination purely in that subject. However, this clashes with
the need for surgeons to be capable of contributing to an
on-call rota for emergencies in the generality of surgery.
It is therefore in that aspect of speciality interest that the
emphasis is placed in the examination.
REGULATIONS RELATING TO THE
INTERCOLLEGIATE SPECIALTY
EXAMINATION
These vary from specialty to specialty and also are regu-
larly updated. You should contact the intercollegiate
specialty examinations board for up to date details of
the regulations in your subject. The address is:
The Intercollegiate Examinations Board
3 Hill Square
Edinburgh EH8 9DR
Tel: 0131 6629222
Fax: 0131 6629444
Web site: http://www.intercollegiate.org.uk
Some regulations are common to all nine SAC subjects:
1. You must hold a medical qualification recognized for
qualification by the General Medical Council or the
Medical Council of Ireland and must have been qualified
for at least 7 years.
2. You must satisfy the current requirements for entry
to an approved higher surgical training programme in
Great Britain or Ireland.
3. You must have completed satisfactorily 4 years of
higher training in the specialty acceptable to the relevant
board:
a. If you are a type I trainee, you are training with a
view to being awarded the Certificate of Completion of
Specialist Training (CCST) by the Specialist Training
Authority of the United Kingdom, the Certificate of
472
THE INTERCOLLEGIATE EXAMINATIONS IN SURGERY
50
Specialist Doctor (CSD) or Specialist Registration with the
Medical Council of Ireland. You must have enrolled with
the relevant SAC and completed the above 4 years of
training within a programme approved by them. You
need to have satisfactory fourth year clinical assessment
form(s) covering this year of training, and the appropri-
ate declaration form signed by the Programme Director,
b. If you are a type II trainee, you are not eligible for
the CCST. You need to be registered with the relevant
SAC and must have spent at least one of the above 4 years
in a training programme in Great Britain or Ireland
approved by the relevant SAC. This mandatory clinical
year must offer experience equating to fourth year level
within the specialist registrar grade and you must obtain
written confirmation of this from your trainer. You require
a satisfactory fourth year clinical assessment form(s) cov-
ering this year of training and the appropriate declaration
form signed by the Programme Director. Any other train-
ing posts completed in Great Britain and Ireland must be
approved by the relevant SAC in order to count towards
the examination. If you wish training acquired outside
Great Britain and Ireland to be taken into consideration,
you need to present supporting documentation at the
time of registration with the SAC.
Key points
• If you are a type II trainee you are not be
eligible for the award of a CCST.
• Passing the examination does not
automatically entitle you to enter type I
training.
4. From 1 January 2003 you will be limited to three
attempts at the examination, after which you must seek
specific counselling, retraining where necessary, and
written support from the Postgraduate Dean and
Programme Director in order to resit again. Attempts
prior to January 2003 will not be counted.
clinical signs. You must then decide upon an appropriate
course of management pertinent to that patient. In
urology, on the other hand, there is very limited scope for
spending much time on clinical examination so there is an
understandable natural reluctance to expose patients and
candidates to the evaluation of multiple rectal examin-
ations. The technical skills required of a neurosurgeon
clearly differ from those of a general surgeon with an
interest in hepatobiliary disease. In my judgement, it is
not only appropriate that there is a difference in exam-
ination format between the subjects but that such differ-
ences are actually essential.
2. Examiners are very concerned to maintain consistent
standards. You can be confident of having an examination
and subject content of equal standard to the other candi-
dates. This has produced much debate within the exam-
inations boards; it is now common practice for all of the
questions in oral examinations to be structured and to
conform to a set pattern. A perceived problem in the clini-
cal arena is the difficulty of arranging for large numbers
of candidates to see a large number of similar patients. In
practice, the clinical examination, particularly of short
cases, closely mirrors the procedure in an outpatient
clinic, where we encounter the vagaries of life and vari-
ances of clinical presentation. The examination tests your
ability to deal with whatever problem presents.
3. Recognize that the examination is not an interroga-
tion on surgical esoterica (Greek esoterikos - eso ~ within;
revealed to an elect few), but a standard of international
authority. However, we all encounter some rare condi-
tions and you must demonstrate your ability to tackle an
unusual problem sensibly. In many of the specialist sub-
jects, particularly general surgery, the field and syllabus
are quite colossal. It is almost impossible to go through
the day of an examination without coming across a
subject where one's knowledge or experience is insuffi-
cient. You must not be unsettled. This is a fact of life in
consultant practice. The examination is carefully
designed to balance areas of difficulty with areas of out-
standing competence or experience.
THE FORMAT OF THE EXAMINATION
1 . The format and style of the examinations differ from
specialty to specialty. Although anxieties have been
expressed about lack of consistency in such an approach,
it is apparent that the nature of the different specialties,
and particularly the clinical material involved, varies
from subject to subject. Thus in orthopaedics the value of
a clinical examination with long cases is considered very
important. You need to be able to talk to an individual
patient and outline the lifestyle problems and relevant
Key points
• Recognize that as a surgeon you must expect
to encounter unfamiliar problems.
• As a surgeon you must display common sense
in difficult circumstances.
To varying degrees, therefore, each of the examinations
is composed of essentially two parts: oral examinations
with two examiners, usually lasting half an hour; and
clinical examinations with two examiners, again lasting
473
50
GENERAL CONSIDERATIONS
half an hour. Some of the subjects also have written exam-
inations that are usually multiple choice.
4. In all of the oral and clinical tests, examiners are
instructed to treat you as if you are a consultant colleague
asked to see an interesting or unusual case. There is room
for debate, and you will be questioned on management
strategies, but the examination should never become rude
or aggressive. Almost without exception the examiners go
out of their way to make you feel at ease within the
understandable constraints of the circumstances.
5. If, however, you feel you have had an unfair or dif-
ficult experience in any part of the examination, speak to
the chairman of the examination board, or one of the indi-
viduals who help organize the examination. You should
settle any matter of discontent immediately, between
parts of the examination. You can then start the next part
in a calm and collected frame of mind, and not carry over
any frustrations or anxieties that might otherwise
threaten your subsequent performance.
6. Take the minimum baggage into the examination.
Briefcases are not permitted. You need little instrumenta-
tion for clinical examinations, as it is usually provided.
Regard the clinical examination as a demonstration of
your routine skills. Do not start with rare tests that you
would not normally employ. Concentrate on being thor-
ough, carrying out appropriate examinations, avoiding
inappropriate ones.
7. Be prepared to discuss papers from the literature.
You may be invited to present some of your own work for
discussion, usually of how you performed the studies,
how they relate to previous or subsequent work and how,
in retrospect, your study could have been improved. You
may be asked to comment on a paper, usually taken from
a major journal. Do not, on this account, assume it is
without fault. The discussion concentrates on the
strengths and weaknesses of the paper.
8. Note that statistical method may enter into the
format. This is not, though, an examination in statistics
but on your understanding and use of simple statistical
methodology in the evaluation of scientific work.
9. The emphasis on basic sciences varies, depending on
the speciality. Although there is a view that basic science
teaching and examination belongs to basic surgical train-
ing, you will be expected to apply relevant, and only
relevant, basic sciences to your clinical subject. A candi-
date whose main interest is in upper gastrointestinal/
hepatobiliary disease should understand the basic phys-
iology of digestion and pancreatic secretion, but will not
be asked the details of the relationships of the thalamus.
THE END OF THE EXAMINATION
^.^.;S ; ^£^^^^^
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1. You either fail or pass. No distinction is made
between a bare pass and high marks. However, in some
subjects a prize or medal is awarded for outstanding can-
didates. As a rule you are notified of your result in an
envelope at the end of the day's examination. If you have
been successful you are usually invited to celebrate with
your examiners before departing. If you are unsuccessful
you do not discuss with the examiners why you have
failed. This is because early experience showed that
examiners and failed candidates can become adversarial,
prejudicing the atmosphere at subsequent examinations
or consultant appointment interviews.
2. If you are unsuccessful, you will, in the following
weeks, receive written details from the chairman on your
weaknesses, together with advice for the future. If you are
unsatisfied with your treatment by the examiners you
may appeal. You can obtain details from the Examinations
Board in Edinburgh.
Good luck to all those who undertake the examination.
Summary
• Do you know whether or not you are
eligible to sit the examination?
• Are you aware of the standard and
conduct of the examination?
• Do you recognize that the Colleges owe it
to the public to pass only those who
demonstrate competence?
• Will you accept that the examiners
appreciate the stress involved and will
treat you courteously?
474
Index
Page numbers in bold refer to figures or tables.
Abbreviated Injury Scale (AIS), 45
ABCDE sequence, 3-8
Abdominal incisions, 232, 232-233
mass closure, 232-233, 385
Abdominal pain, 50
Abdominal surgery, 356
postoperative complications, 379
wound dehiscence, 385
see also Gastrointestinal surgery
Abdominal trauma, 25-26
ultrasound (FAST) assessment, 60
Abdominal wall trauma, 26
ABO blood groups, matching, 88
ABO incompatibility, 101, 352
Abrasion, 242-243, 246
Abscess, postoperative, 383
Absolute risk reduction (ARR), 448
Acarbose, 73
Accident and emergency (A & E)
department
initial resuscitation, 3-8
monitoring, 8-13
secondary survey, 13-18
Achondroplasia, 419
Acidaemia, 119
Acid -base balance, 119-122
effects of surgery, 318
interpretation of changes, 120-121
new insights into, 121-122
normal saline and, 117
in resuscitation, 4-5, 10, 10-12
terminology and definitions, 119-120
traditional view, 119-121
treatment of disturbances, 123
Acid citrate dextrose, 377
Acidosis, 10, 10, 119-120
Bohr effect, 12
compensatory changes, 119-120
metabolic see Metabolic acidosis
respiratory, 10, 10 r 119
Acids, weak, 122
Acromegaly, 71-72
ACTH, 30, 315
Activated partial thromboplastin time
(APTT), 92, 93, 103, 103, 380
Activated protein C, 321
Acupuncture, 359
Acute lung injury (AU), 34, 318
Acute normovolaemic haemodilution
(ANH), 94-95, 103
Acute pain services (APS), 182, 369
Acute-phase reactants (APRs), 31, 316,
317
Acute-phase response, 314, 316-317
Acute Physiology and Chronic Health
Evaluation (APACHE) score,
147, 167
Acute renal failure, 41, 378, 394-395, 401
Acute respiratory distress syndrome
see Adult respiratory distress
syndrome
Acute tubular necrosis, 394
Addiction, 78, 366, 408
Addisonian crisis, 15
Addison's disease, 72
Adenomatous polyposis coli (familial
adenomatous polyposis, FAP),
262, 420-421, 421
Adenosine, 68
ADH see Antidiuretic hormone
Adhesions, intra-abdominal, 233
Adjuncts to surgery, 199-205
Adjuvant therapy, 269, 288
Adolescents, consent issues, 158-159
Adrenal gland disorders, 72
Adrenaline (epinephrine)
in arrhythmias, 69
in local anaesthesia, 181, 181, 353, 363
in response to injury, 30, 31-32, 314
Adrenocortical hyperfunction, 72
Adrenocortical insufficiency, 72, 315
Adrenocorticotrophic hormone (ACTH),
30, 315
Adult respiratory distress syndrome
(ARDS), 34, 34, 318
in massive transfusion, 104
postoperative, 381
Advance directives, 160
Advanced life support, 6-7, 7
Advanced Trauma Life Support (ATLS),
3,8
Adverse incidents (occurrences)
analysing and correcting, 432
reporting, 183, 229, 438
screening, 431
see also Audit
Advice, giving, 460
Adynamic (paralytic) ileus, 318, 356
Affective disorders, 78
Afterload, 390
Agammaglobulinaemia, primary, 85
Aggressive behaviour, 460
Agitation
in respiratory distress, 394
terminal, 413
AIDS see HIV infection/ AIDS
Air conditioning, 184
Air filters, 184, 209
Air flow systems, theatre see Ventilation
systems, theatre
Airway
assessment, in primary survey, 4
inhalational injury, 44
management
in initial resuscitation, 4
postoperative, 349
obstruction, 14, 354-355
trauma, 22
Albumin, 107
plasma, 76, 76, 125
in hypovolemia, 113-114, 114
response to injury, 320
solutions, 100, 115, 116
Alcohol misuse (alcoholism), 78, 263
head injury, 13
hypoglycaemia, 13
Aldosterone, 32, 315
Aldosteronism, 72
Algorithms, 148
Alkalaemia, 119
Alkalosis, 10, 10, 119-120
compensatory changes, 119-120
metabolic, 10, 11, 119
respiratory, 10, 10, 119
Alkylating agents, 287
Allodynia, 405
Allografts, 87-88, 249
rejection see Rejection, graft
Alloy implants, 203
Alopecia, chemotherapy-induced, 291
a-adrenergic blockers, 72, 170
475
INDEX
a-fetoprotein (AFP), 88
in germ cell tumours, 303-304, 304
in hepatocellular carcinoma, 307
Alveolar gas exchange, failure, 14
American Society of Anesthesiologists
(ASA) score, 147, 167, 168
Amethocaine, 180, 181
Amino acids, 319, 328
Aminoglycoside toxicity, 376
Amniotic membrane, 200
Amphiarthroses, 337
Amyloid disease, 401
Anaemia, 74-75
of chronic disease (ACD), 91
classification, 91
genetic disorders, 419
oxygen dissociation curve and, 12
postoperative, 105
preoperative assessment, 91-92
Anaesthesia, 174-182
assessing fitness for, 54
general see General anaesthesia
regional, 180-181, 182, 363-365
total intravenous (TIVA), 177
Anaesthetic agents
intravenous, 174, 174-175
volatile, 176, 176-177, 178
Anaesthetist, 174
acute pain services, 369
premedication, 1 72-1 74
preoperative assessment, 172
Analgesia
of anaesthesia, 178
in chronic and terminal illness,
406-409
pain ladder, 179
patient-controlled (PCA), 362
postoperative, 179, 351, 360-366
pre-emptive, 179, 181-182, 365
recent advances, 181-182
in terminal phase, 413
three-step regimen, 406
topical, 180, 181
Analgesics, 360-363
premedication, 173, 173, 178
relative efficacy, 363, 363
sites of action, 358, 358
see also specific agents
Anaphylactic shock, 14, 101, 390
Anastomotic leakage, 384
Anastrozole, 292
Anatomico-pathological grid, 51, 51
Anger, 404
Angina, 374
unstable, 65, 66
Angiogenesis
tumour, 261-262
in wound healing, 245, 324
Angiography, intraoperative,, 196
Anion gap, 121
Anorexia, in cancer, 409-410
Anterior cruciate ligament, 334, 335
Antiandrogens, 293, 293
Antibiotics
adverse effects, 375-376
antitumour, 287
control of resistant organisms, 207-208
preoperative, 166-167
prophylaxis, 166-167, 212-213,
382-383
resistance, 207, 375
resistant organisms, 208
Antibodies, 83
binding region, 83
deficiencies, 85
monoclonal see Monoclonal antibodies
polyclonal, 84
structure and synthesis, 84, 84
Antibody-dependent cellular
cytotoxicity (ADCC), 84
Antibody-mediated immunity, 83-85
deficiency, 85
Anticholinergic drugs, 173, 173-174
Anticholinesterase drugs, 78
Anticoagulants, 93
concurrent therapy, 80, 165
thromboprophylaxis, 167, 380
in venous thromboembolism, 380
see also Heparin; Warfarin
Anticonvulsant drugs, 77
Antidiuretic hormone (ADH,
vasopressin)
deficiency, 72
response to surgery, 315
in trauma, 30, 32
Antiemetic drugs, 410-411, 411
Antifibrinolytic agents, 105
Antigen-presenting cells (APCs), 85, 86
Antigens
recognition, 85-86
tumour, 88
Antiglobulin test, indirect, 94
Antihypertensive therapy, 66
Antilymphocytic globulin (ALG), 88, 251
Antimetabolites, 287
Antioestrogens, 292, 293
Antisepsis, 183-184, 208-212
Antiseptics, 210, 211
Antithymocyte globulin (ATG), 88
Antithyroid drugs, 170
Anxiety
in chronic and terminal illness,
403^04
perioperative, 78, 172, 314
Anxiolytic drugs, 172-173, 173
Aorta
dissecting thoracic, 14
traumatic injuries, 22, 26
Aortic aneurysm, abdominal, 14, 426
Aortic stenosis, 67-68
APACHE score, 147, 167
Apoptosis, 245, 259, 260
avoidance by cancer cells, 261
in surgical trauma, 317
Aprotinin, 104
Arachnoid mater, 23, 23
ARDS see Adult respiratory distress
syndrome
Arginine vasopressin (AVP) see
Antidiuretic hormone
Argon beam coagulator, 195, 195
Argon lasers, 188, 189
Armed conflict, 226
Aromatase inhibitors, 292, 293
Arrhythmias, 68-70
cardiac output and, 389
in massive transfusion, 104
risk of surgery, 374
Arterial blood gases, 10, 121
interpretation, 120-121, 122-123
postoperative monitoring, 350
in resuscitation, 4-5, 10-12
Arterial trauma, 27-28
Arthroscopy, 238
ASA score, 147, 167, 168
Ascites, 76, 77, 378
Asepsis, 208-212
Aspiration of gastric contents, 13, 176,
356
Aspirin, 360
postoperative bleeding problems, 98,
105
preoperative cessation, 90, 93, 165
Assisted ventilation, 393-394
in myasthenia gravis, 78
in resuscitation, 4
Asthma, 70
Asystole, 14
Atelectasis, 381,409
Atherosclerosis, 374
Atracurium, 178
Atrial fibrillation, 68
Atrial flutter, 8, 68
Atrial natriuretic peptide (ANP), 31 7
Atrioventricular (AV) heart block, 69
Atropine
in heart block, 69
for nerve gas poisoning, 17
premedication, 173, 174
in recovery phase, 1 79
Audit, 142, 428-436, 437^38
in American surgical practice, 431-433
attitudes to, 429-430
clinical, 428^29, 430, 438
committee, 430
comparative, 431
computers, 433-434
criterion, 431
cycle, 434, 434-435
definitions, 428^29
educational component, 434
ethics and confidentiality, 433
implementing change, 434—435
infection, 213
medical, 429, 437^138
methods, 430-434
national, 431
outcome, 431
Autoclaving, 201, 211
Autocrine actions, 325
Autografts, 249
Autoimmunity, 83, 87
Autonomic neuropathy, diabetic, 73
Autotransplantation, 87
AVPU mnemonic, 8, 35
Avulsion injuries, 243
Axes, joints, 337, 337
Axonotmesis, 40, 341
476
INDEX
Axons, 27
Azathioprine, 87, 88, 251-252, 252
Bacteria, gut translocation, 126, 127, 318
Bacterial infections
in antibody deficiencies, 85
transfusion-transmitted, 102, 102
Bad news, imparting, 460^62
Bag-valve-mask ventilation, 4
Bariatric surgery, 374
Barium imaging, 60
Baroreflex, in trauma, 30
Base excess (BE) (or deficit), 10, 11-12,
120, 121
standard (SBE), 120, 121
Basilic vein, cutdown, 5
Battery, 157
Bcl-2 gene family, 261
BCR-ABL fusion protein, 294, 295
Beards, 209
Beevor's sign, 39
Benefits, measurement, 443
Benign prostatic hypertrophy (BPH),
306, 307
Benzodiazepines
induction of anaesthesia, 174, 175
overdose, 15
premedication, 173, 173
Bereavement, 413
(^-microglobulin, 308
Beta-blockers, 65, 170, 320
Bias
lead time, 423, 456
length, 423
publication, 450-451
spectrum, 447
Bicarbonate
buffer system, 10, 120
concentration ([HC0 3 ]), 120, 121
standard (SBC), 120, 121
therapy see Sodium bicarbonate
Biliary atresia, 254
Biliary obstruction, malignant, 268
Biliary stenting, preoperative, 169
Biliary surgery 169-170
Biliary tree, trauma, 25
Bilirubin, serum, 76
Biological anticancer therapy, 293-295,
294
Biomechanics, traumatic injury, 19-21
Biopsy, 58
image-guided, 62
sentinel lymph node (SLNB), 267-268
tumour, 266
Bladder cancer, 297
Bladder trauma, 26
Blalock, Alfred, 112
Blast injuries, 21, 21, 25
Bleeding see Haemorrhage /bleeding
Bleeding disorders, 75, 93
postoperative assessment, 105
preoperative assessment, 92-93
see also Coagulation disorders
Bleeding time, 92
Bleomycin, pulmonary toxicity, 291-292
Blinding, in clinical trials, 448
Blood
crossmatching, 94
grouping and compatibility testing,
94, 96-97
intra- and postoperative salvage, 94,
103-104, 192
order schedules (SBOS/MBOS), 94
postexposure measures, 219-220
preoperative autologous deposit
(PAD), 90, 95
procedures with risk of contact, 218
products for transfusion, 95-96, 96,
118
reducing exposure to, 219
spillages, 212, 218
uncrossmatched, 95
whole, 93, 97
Blood component therapy see Blood
transfusion
Blood disorders see Haematological
disorders
Blood gases, arterial see Arterial blood
gases
Blood /gas partition coefficient, 176
Blood loss, 117-118
quantification, 103, 118
reducing intraoperative, 104
see also Haemorrhage/ bleeding
Blood pressure (BP)
collapsed patient, 8-9
determinants, 389
in renal dysfunction, 395
in shock, 5
see also Hypertension; Hypotension
Blood tests, 57
Blood transfusion (blood component
therapy), 95-100, 117-118
autologous, 94-95, 103-104, 192
avoiding, 94
complications, 100-103, 101, 352, 376
disadvantages, 91, 117-118, 118
elective surgery, 93-94
emergency surgery, 95
errors, 100-101
future directions, 105
immune complications, 101, 377
incompatible, 101, 352, 376-377
indications, 97-98
intraoperative, 103-105
massive, 98, 104, 118, 377
in open heart surgery, 104-105
postoperative, 105, 352
preoperative, 74
preoperative arrangements, 93-95
in prostatic surgery, 105
refusal, 160, 161, 163
in sickle cell disease, 92
transmission of disease, 99, 102, 102,,
377
Blow-out fractures, 24
B lymphocytes, 83-84, 86 f 87
clonal expansion, 83
deficiencies, 85, 87
Body fluids
electrolyte content, 115
postexposure measures, 219-220
preventing exposure to, 13, 218, 219
procedures with risk of contact, 218
spillages, 212, 218
transmitting blood-borne viruses, 217
Body temperature
monitoring during resuscitation, 9
oxygen dissociation curve and, 12
postoperative changes, 317
postoperative monitoring, 350, 355
response to injury, 30, 314
Bohr effect, 12
Bomb blast injuries, 21, 21, 25
Bone, 331, 342-348
adult, 343-344
blood supply, 346
cancellous, 343
healing, 39, 327-328, 346
after fixation, 347
electrical stimulation, 345
small defects, 344
immature, 343
implants, 346-347
mechanical stress, 344
metastasis, 279, 346
necrosis, 327
neoplastic lesions, 345
pain, 405, 408
remodelling, 328, 344
surgical procedures, 344-345
trauma see Fractures
woven, 327, 328
Bone (acrylic) cement, 204, 348
Bone marrow failure
blood component therapy, 97-98
cytotoxic drug-induced, 290-291
Bone marrow transplantation,
allogeneic, 88
Bovine spongiform encephalopathy
(BSE), 102
Bowel obstruction, 169
fluid replacement, 111
in terminal illness, 411-412, 412
Bowel preparation, 169, 382
Bowel trauma, 25, 26
Bowen's disease, 241, 244
Bradycardia, suxamethonium-induced,
175
Bradykinin, 316
Brain injury
contra coup, 36-37
diffuse axonal injury, 36-37
primary, 36
secondary, 36
traumatic, 34-37
Brain metastases, 279
Brainstem herniation (coning), 23, 35
BRCA-1 and BRCA-2 genes, 262, 421,
421
Breast cancer, 265
familial, 421, 421
molecular grading, 266
non-surgical treatment, 292, 295-296,
296, 297
screening, 425, 426
spread, 267
477
INDEX
Breast cancer (cont.)
surgical management, 267
tumour markers, 307-308
Breast implants, silicone, 204
Breathing
assessment, primary survey, 4
management, in resuscitation, 4-5
postoperative monitoring, 349,
367-368
British National Formulary (BNF), 131,
133,135
Bronchitis, chronic, 70-71
Bronchogenic cancer see Lung cancer
Bronchospasm, 70, 355
Brown-Sequard syndrome, 39
Bruton's disease, 85
Buffers, 120
Bupivacaine, 180, 181, 363-364
maximum dose, 353, 363
Buprenorphine, 179, 362
Burns, 20-21, 42-45, 243-244
assessment, 244
chemical, 43
depth, 43
diathermy, 187-188, 243
electrical, 20-21, 43, 243
full thickness, 43, 244
metabolic response, 31
mustard gas, 17
partial thickness, 43, 244
shock, 42^3
superficial, 43
toxic shock syndrome, 43-44
CA 15-3, 307-308
CA 19.9, 304
CA 50, 304
CA125, 305-306, 308,426
Cachexia, cancer, 378
Calcitonin, 308
Calcitonin gene-related peptide, 308
Callus, 39, 327-328, 346
Camptothecins, 287
Cancer, 265-270
adjuvant therapy, 269
advanced incurable see Terminal
illness
anorexia, 409-410
biological therapy, 293-295, 294
cachexia, 378
chemotherapy see Chemotherapy
communication with patients, 299
curative (Rq) resection, 266
evaluation of new drugs, 300, 300
genetic susceptibility, 262, 417, 420,
420-422
hormone therapy, 292-293, 293
immunology, 88
investigations, 54
minimal access surgery, 239
multidisciplinary approach, 269-270,
289
non-surgical treatment, 295-299
pain, 405, 409
palliative surgery, 268
pathogenesis, 259-264, 420
pathological diagnosis/grading, 266
postoperative complications, 378
preoperative assessment, 265-266
radiation-induced, 281-282
radiosensitivity, 273
radiotherapy see Radiotherapy
reconstructive surgery, 269
recurrence, 268
response evaluation (RECIST) criteria,
289-290
secondary, 268
second tumours after, 281-282, 292
spread, 266-268
staging, 54, 266
statistics, 265
surgical management, 266-269
symptoms in advanced, 404, 404-405
see also specific types
Cancer family syndrome, 422
Cannulae, 202
Capecitabine, 297
Capillary membrane, 107-110
Capillary refill time, 9
Carbimazole, 170
Carbohydrate metabolism, in response
to injury, 30, 31,319
Carbon dioxide (CO2)
in acid-base balance, 120
tension (partial pressure)
arterial see PaC0 2
end- tidal, 10-11
total (TC0 2 ), 120, 121
Carbon dioxide (C0 2 ) lasers, 188-189
Carbon fibre, 203
Carbonic acid, 120
Carbonic anhydrase, 120
Carbon monoxide
poisoning, 16, 44
in smokers, 70
Carboxyhaemoglobin, 44, 70
Carcinoembryonic antigen (CEA), 88,
268, 304-305
Carcinogenesis, 259-264, 420
abnormal cell cycle control, 260,
260-261
chemotherapy-induced, 292
genetic damage, 262-263
Knudson's two-hit hypothesis, 263,
263, 420
multi-step pathway, 263, 263
Carcinogens, chemical, 262, 262
Carcinoid tumours, 308
Cardiac arrest
acid-base balance, 11-12, 123
resuscitation, 6-8
Cardiac index, 113, 168
Cardiac massage
external chest compressions, 6
internal, 7-8
Cardiac output, 112, 113
determinants, 389-390
response to surgery, 318
Cardiac tamponade, 22
Cardiac transplantation, 79, 253-254, 255
Cardiogenic shock, 14, 32, 390
Cardiomyopathies, 68, 68
Cardiopulmonary bypass (CPB), 104-105
Cardiopulmonary resuscitation (CPR),
6-8
Cardiotoxicity, cytotoxic drugs, 291
Cardiovascular disease, 65-70
age-related risk, 373, 373
fluid management, 113
preoperative preparation, 167
risks of surgery, 374, 374-375
Cardiovascular risk assessment, 65
Cardiovascular system
effects of pain, 359
pathophysiology in critical illness,
389-391 '
response to fluid deficits/ 112-113
response to injury, 32-33, 314, 318
see also Circulation
Carotid pulse, 5, 6
Cartilage, articular, 339-340
Catecholamines, 30, 314
see also Adrenaline
Catgut, 201, 202
Catheters, 202
Caudal epidural block, 365
Cavitron UltraSonic Aspirator (CUSA),
194
CD3, 86
CD4 T helper cells, 86, 86, 216
CD8 cytotoxic T cells, 85, 86
CEA see Carcinoembryonic antigen
Celecoxib, 361
Cell adhesion molecules (CAMs), 261
Cell cycle control, 259-260, 260
abnormal, 260-261
Cell division, cytotoxic drug actions,
285, 285
Cell-mediated immunity, 85-87
deficiency, 86-87
Cell membrane, 108-109
Cell proliferation, in wound healing,
322, 323-324
Cell salvage, autologous, 94, 103-104,
192
Censored observations, 450
Central nervous system
infections, 15
wound healing, 328
Central venous cannulation, 5-6
Central venous pressure (CVP), 112-113,
389-390
monitoring during resuscitation, 9-10
Centre for Reviews and Dissemination,
York, 139, 451
Centromere, 417
Cephalosporins, 167
Cerebellar herniation, 36
Cerebral oedema, in head injury, 35
Cerebral perfusion pressure (CPP), 35
Certificate of completion of basic
surgical training (CCBST), 468,
471
Certificate of Completion of Specialist
Training (CC5T), 472-473
Certificate of Specialist Doctor (CSD),
472-473
478
INDEX
Cervical cancer, 298, 308
screening, 425, 426
Cervical spine
immobilization, 3-4, 13
injuries, 37, 37
Chance fracture, 19
Change
implementing, 140, 140-142, 434-435
individual, 141, 141
organizational, 141, 141
Charnley, Sir John, 348
Charnley exhaust gown, 200, 208
Charnley tent, 184
CHART (continuous hyperfractionated
accelerated radiotherapy),
275
Chemical burns, 43
Chemical weapons, 17
Chemotherapy, 284-301
adjuvant, 269, 288
clinical assessment of response,
289-290
combination, 288
evaluation of new drugs, 300
highly sensitive tumours, 298-299
immune effects, 87
intra -arterial, 289
intrathecal, 289
neoadjuvant, 288
in osteosarcoma, 270
palliative, 288
performance status and, 290
principles, 284-290
risks of surgery after, 376
timing, 288
toxicity, 290-292
see also Cytotoxic drugs
Chest
flail, 4, 22
incisions, 233
trauma, 21-22
Chest compression, external, 6
Chest drains, 353
Chest wall trauma, 21-22
Chilblains, 244
Children
consent, 158-159
drug prescribing, 134
organ transplantation, 253, 254
postoperative analgesia, 366
preoperative preparation, 166, 170
resuscitation, 5
water requirements, 109-110, 110
Child's grading of liver disease, 76, 76
Chitosan, 200
Chlorhexidine gluconate, 210
Chlorpropamide, 73
Cholangiography, intraoperative,
195-196
Cholangitis, acute, 169
Cholecystectomy, laparoscopic, 239,
378-379
Choriocarcinoma, 299, 303
Chromatolysis, 40, 328
Chromosomal disorders, 417
Chromosomes, 417
Chronic illness, 402-414
communication, 403
definition, 402
emotional reactions, 403-404
symptom control, 404-412
Chronic obstructive airways disease
(COAD), 70-71, 170
oxygen therapy, 393
resuscitation, 5
Ciclosporin, 87, 88, 251, 252, 376
side-effects, 252
Circulation
assessment, 5
postoperative care, 349-350
in primary survey, 5-8
traumatic injuries, 22
see also Cardiovascular system
Circulatory overload, 103
Cirrhosis, 76-77, 170
Cisatracurium, 178
Cisplatin, 291
Clean air enclosures, 199
Clean-contaminated operations, 166, 206
antibiotic prophylaxis, 212-213
Cleaning, 210-211
Clean operations, 166, 206
antibiotic prophylaxis, 166, 212
postoperative infections, 382
Clinical effectiveness, 139, 438
Clinical examination, 51-52
intercollegiate specialty examination,
473, 474
MRCS examination, 467, 468, 470
objective structured (OSCE), 468, 470
Clinical governance, 437-441
components, 438^140
reporting outcomes, 438
scope, 438
Clinical skills, 146-147
Clinical trials, 132, 300
see also Randomized controlled trials
Clips, 201-202, 234
Clostridium difficile, 208, 376
Closure, 246-247
abdominal incisions, 232-233, 385
factors complicating, 246
no skin loss, 246
primary, 246
skin, 202, 234
in skin loss, 246-247
surgical incisions, 231-232, 246
Clothing
protective, 218, 218
theatre, 184, 199, 200, 208-209
Clotting see Coagulation
Coagulation, 323
Coagulation disorders, 15, 33, 75
blood component therapy, 98, 99
in chronic liver disease, 77
inherited, 419
in massive transfusion, 104
postoperative, 320
postoperative haemorrhage, 386
preoperative assessment, 92-93
preoperative management, 169
risks of surgery, 377
see also Bleeding disorders
Coagulation factors
concentrates, 100
in fresh frozen plasma, 99
in obstructive jaundice, 377
Cocaine, 180, 181
Cochrane Collaboration, 139
Cochrane Library, 451
Codeine, 179, 407
Coeliac disease, 87
Coexisting disease, 64-81
drug therapy, 80, 80
evaluation, 54
management aims, 65
preoperative preparation, 167-168
see also specific diseases
Cold, common, 170
Cold injury, 243-244
Colic, 408, 412
Collagen, 332
in wound healing, 245, 324
Collapse
causes, 14-15
diagnosis of cause, 13-16
initial resuscitation, 3-8
monitoring, 8-13
Colleagues, 460
Collodion, 204
Colloid osmotic pressure (COP), 107-108
Colloid solutions, 109, 115-117, 116
electrolyte balanced, 117
Colonic anastomoses, leakage, 384, 384
Colonic pseudo-obstruction, 356
Colonic trauma, 26
Colonoscopy, screening, 424
Colony stimulating factors (CSFs), 294
Colorectal cancer, 265
adjuvant therapy, 269, 297
genetic model for development, 420
hereditary, 421-422
local invasion, 267
metastases, 267, 268
non-surgical treatment, 297
palliative surgery, 268
recurrent, 268
risks of blood transfusion, 377
screening, 424^125, 426
tumour markers, 304-305
Colostomy, 169
Coma
causes, 35
pupil size and responses, 8, 9
resuscitation, 3-8
see also Consciousness, altered level
Commission for Healthcare Audit and
Inspection (CHAD, 440
Commission for Health Improvement
(CHI), 440
Common variable immunodeficiency
(CVID), 85
Communication, 458-462
cancer patients, 299
with colleagues, 460
consent aspects, 160, 163
imparting bad news, 460-462
non-verbal, 458-459
479
INDEX
Communication (cont.)
with patients, 459— £60
with relatives, 460
skills, MRCS examination/ 467,
470-471
in terminal illness, 299, 403
in terminal phase, 413
verbal, 458
Comorbidity see Coexisting disease
Comparative statistics, 452, 456
Compartments, limb, 28, 334, 335
pressure monitoring, 40-41
Compartment syndrome, 13, 40, 40-41,
334
pathogenesis, 40, 336
Competence, clinical, 225
Complaints, 229
Complementary therapy, 409
Complement deficiency, 83
Complement system/ 82
Complete response (CR), 289
Complexity theory, 144
Compliance, screening, 426
Complications see Postoperative
complications
Compression forces, 19
Compression stockingS/ graduated
(GCS), 167, 451, 451-452
Computed tomography (CT), 60-61
interventional, 62
intraoperative, 62
three-dimensional reconstruction, 63
Computers
in clinical audit, 433-434
for diagnosis, 49
Concussion, 36
Confidence intervals, 449, 452
Confidentiality, 162-163, 433, 464
Conflict, armed, 226
Conflicts of interest, 228
Conformal radiotherapy, 274, 275
Congenital abnormalities, 373, 420 7 426
Congenital heart disease, 66-67
Coning, 23, 35
Connective tissue
genetic disorders, 419
response to trauma and surgery, 331,
332-337
trauma, 331-332
Conn's syndrome, 72
Consciousness, 35
altered level
blood glucose estimation, 13
causes, 35
in critical illness, 395
resuscitation, 3-8
secondary survey, 13, 16
in shock, 5
in trauma, 35, 36, 37
see also Coma; Unconscious patients
Consent (including informed consent),
155-164
children, 158-159
confidentiality and, 162-163
implied, 157
legal aspects, 157-159
in mental handicap, 159
moral aspects, 155-156
in practice, 156, 159-161, 166
in psychiatric illness, 159
surgical research, 161-162
unconscious patient, 158, 161
Consent form, 156, 157
Constipation, 408, 412
Contaminated operations, 166, 206
antibiotic prophylaxis, 167, 212-213
Continuing professional development,
439
Continuous hyper fractionated
accelerated radiotherapy
(CHART), 275
Continuous positive airway pressure
(CPAP), 393
Contra coup injury, 36-37
Contractility, myocardial, 390
Contractures, 234, 409
Contrast radiology, 58, 59, 60
Contusion, 19, 242
Convection, 399, 399
Coombs' test, 97
Coronary artery disease, 65-66
in diabetes, 73
preoperative preparation, 170-171
Corticospinal tract, 38, 38
Corticosteroid (steroid) therapy, 80
in chronic and terminal illness, 409,
410, 412
immune effects, 85, 87, 376
risks of surgery, 376, 379
side-effects, 252
transplant recipients, 251-252
Corticotomy, 347
Cortisol, 30, 31-32, 315
Cosmetic aspects, incisions, 231
Cost effectiveness, 146, 442-443
in clinical practice, 443-444
measurement, 442, 443
Costs
drugs, 133
investigations, 55, 443
measurement, 443
minimal access surgery, 239, 443
organ transplantation, 255
screening, 427, 443
Counselling
bereavement, 413
preoperative, 359
Craniospinal irradiation, 278
Crash induction, 175-176
Creatinine, serum, 400
Creutzfeldt-Jakob disease (CJD), 211
variant (vCJD), 95, 99, 102, 211
Cricoid pressure, 176
Cricothyroidotomy, 4, 355
Criterion audit, 431
Critical appraisal, 142, 454-457
Critical care see Intensive care
Crohn's disease, 87 ', 169
Crush syndrome, 41
Cryoprecipitate, 75, 99
Cryosurgery (cryotherapy, cryocautery)/
192-194, 193, 244
Crystalloid solutions, 110, 111, 117
Cullen's sign, 26
Curare, 177
Cushing's reflex, 35
Cushing's syndrome (adrenocortical
hyperfunction), 72
Cyanide poisoning, 16, 44-45
Cyanoa cry late tissue glues, 204, 234
Cyanosis, postoperative, 354-355
Cyclizine, 412
Cyclo-oxygenase, 360-361
Cyclo-oxygenase (COX) 2 inhibitors, 1 73,
178,179,361
Cyclotrons, 272
Cytochrome P450 (CYP450) enzymes,
136
Cytokeratins, 308
Cytokines, 82, 86
recombinant, cancer therapy, 293-294
in response to injury, 314, 316
in wound healing, 326-327
Cytology, 58
Cytotoxic drugs, 285-292
administration, 289
classification, 286, 287
fractional cell killing, 286
likelihood of cell killing, 288
mechanisms of action, 285, 285, 286
resistance mechanisms, 288
risks of surgery and, 376
routes of administration, 289
toxicity, 290-292
Cytotoxic T cells (CD8), 85 f 86
Dacron, 203
Dantrolene, 419
Data analysis, surgical logbook, 465
Data collection
by hospitals, 465
surgical logbook, 463-464
Data protection, 464-465
Daycase surgery
postoperative analgesia, 351, 366
postoperative care, 353-354
D-dimer assay, 380
Deafferentation pain, 405
Debridement, 245-246
Deceleration injuries, 19, 20
Decision making, 144-151
aids to, 146-147
in emergencies, 146
essentials, 145-146
in intensive care, 388-389
obstacles to good, 146
patient participation/ 145-146, 460
risk management, 147
Decisions
codified, 14&-149
expected, 149-150
types, 148-150
Decision trees, 148, 148
Decontamination, 210
Deep vein thrombosis (DVT), 380-381
complications, 380-381
diagnosis, 380
480
INDEX
in orthopaedic surgery, 379
prophylaxis see Thromboprophylaxis
risk factors, 167
treatment, 380
Defence reaction, 29, 29-30
Defibrillation, 6-7
internal, 8
Degloving injuries/ 243
Dehydration
assessment of fluid deficit, 112-113
fluid management, 111-112
in terminal illness, 410
Dendritic cells, 83, 86
Denial, 404
Depression, 78, 404
Dermis, wound healing events, 324
Dermoid cysts, implantation, 324
Desflurane, 176 r 177
Desmopressin (DDAVP), 104
Despair, 404
Dexamethasone, 412
Dextrans, 100, 115-117, 116
Dextrose solutions, 111
Diabetes insipidus, 72
Diabetes mellitus, 72-74
chronic complications, 73
kidney and pancreas transplantation,
253, 254
postoperative care, 350
risks of surgery, 375
surgical regimens, 73, 73-74
vascular surgery, 171
wound healing, 242, 245, 329,
375
Diabetic ketoacidosis, 375
Diabetic nephropathy, 375
Diabetic neuropathy, 73, 342
Diagnosis, 51, 52
clinical, 49-52
computer, 49
examination, 51-52
gold standard test, 445^46
history, 49-51
investigations, 51, 52, 53-54
not made, 52
'pay-off/ 51
radiological techniques, 62
statistical analysis, 445-447, 446
Dialysis, 76, 398^01
indications, 400
long-term effects, 401
methods, 400-401
principles, 398-400, 399
see also Haemodialysis; Peritoneal
dialysis
Dia morphine
in chronic and terminal illness, 407,
407,412,413
postoperative analgesia, 179
premedication, 173
routes of administration, 361, 362
side-effects, 408
Diaphragm, traumatic injury, 25
Diaphysis, 343
Diarrhoea, enteral feeding and, 129
Diarthroses, 337
Diathermy, 185-188
bipolar, 186, 186
burns, 187-188,243
cutting, coagulation and blend, 186
earth-referenced generators, 186
isolated generators, 186-187
in laparoscopic surgery, 188, 379
monopolar, 186, 186
pacemakers and, 70, 1 88
patient plate, 186, 187
safety, 187-188
Diazepam, 173
Diethyl ether (ether), 173, 176, 176
Diets
disease-specific, 128
enteral, 128, 396
polymeric, 128
predigested or elemental, 128
Diffuse axonal injury (DAI), 36-37
Diffusion, 398-399, 399
DiGeorge syndrome, 86-87
Digoxin, 67
Dihydrocodeine, 407
2,3-Diphosphogly cerate (2,3-DPG), 12,
97,377
Diplopia, 24
Dirty wounds, 206
Disability, in primary survey, 8
Disinfectants, chemical, 211
Disinfection, 210-211
endoscopes, 192, 203, 211
Disposable accessories, 202
Disposable clothing, 184, 200
Dissection techniques, in minimal access
surgery, 239
Disseminated intravascular coagulation
(DIC), 33, 99, 105
Diving injuries, 28
DNA,417
DNA damage
in cancer pathogenesis, 260, 262-263
cytotoxic drug-induced, 285, 285
radiation-induced, 272, 273
DNA repair, 263, 422
DNA synthesis, 260, 260
cytotoxic drug actions, 285, 285
Dominant inheritance, 418
Domino procedure, 254
Donabedian's structure, process and
outcome model, 430
Down syndrome, 419
Doxorubicin, 286
toxicity, 290, 291
Drains, surgical, 202, 212, 352-353
complications, 353
Drapes, 184, 210, 230-231
polyurethane incise, 231, 235
Dressings, 200, 234-235
Drug abuse, 78
Drug and Therapeutics Bulletin (DTB), 133
Drugs, 131-137
adverse effects, 132-133, 375-376
in cardiac arrest, 8
in children, 134
concurrent, 80, 80, 165, 172
convenience and cost, 133
development and licensing, 131
efficacy, 132
in elderly, 134, 373
genetic background and, 135
information sources, 133-134
interactions, 136
in kidney disease, 135
in liver disease, 135
metabolism, in obstructive jaundice,
378
poisoning, 15-16
postmarketing surveillance, 133
practical use, 134-136
in pregnancy, 134-135
in resuscitation, 6
selection, 131-134
Dukes' staging of colorectal cancer, 269
Duodenal trauma, 25-26
Dural puncture, inadvertent, 364
Dura mater, 23, 23
Dysphagia, in terminal illness, 410, 410
Dysrhythmias see Arrhythmias
E2F transcription factors, 261
Ebb phase, response to trauma, 29-31
ECG see Electrocardiogram
Economics, 442-444
see also Costs
Ectopic pregnancy, ruptured, 14
Edrophonium, 78, 179
Education, 439
Educational component, audit, 434
Ehlers-Danlos syndrome, 332, 419
Eisenmenger's syndrome, 67
Elastic fibres, 332
Elastin, 332
Elderly, 79-80
drug therapy, 134, 373
intensive care unit admission, 388
kidney transplantation, 253
postoperative analgesia, 366
risks of surgery, 373
Elective lymph node dissection (ELND),
267
Electrical burns, 20-21, 43, 243
Electrical stimulation, bone healing, 345
Electrocardiogram (ECG)
in cardiac arrest, 6
in heart block, 69
preoperative, 65
Electrolyte(s)
balance, 109-110
effects of surgery, 318
postoperative management, 352
replacement, 114-115
see also Potassium; Sodium
EMBASE, 451
Emergencies
consent, 158
decision making in, 146
professionalism in, 226
Emergency admissions unit, 443
Emergency surgery
blood transfusion, 95
preoperative preparation, 167-168
481
INDEX
EMLA, 181
Emotion, 314
Emotional reactions, terminal illness,
403^04
Empathy, 461
Emphysema, 70-71
subcutaneous, 24
Endocrine action, 325
Endocrine anticancer therapy, 292-293,
293
Endocrine dysfunction, 71-74
Endocrine response to surgery, 314,
315-316
Endocrine surgery, 170
Endoluminal endoscopy, 238
Endometrial ablation, 194
Endometrial cancer, 293
Endoneurium, 27, 340
^-Endorphin, 317
Endoscopes, 190-192, 203
care, 191-192
cleaning and disinfection, 192, 203,
211
flexible Hbreoptic, 190-191, 191, 192
rigid, 191-192
Endoscopic retrograde
cholangiopancreatoscopy (ERCP),
169
Endoscopic ultrasound (EUS), 60
Endoscopy, 58
endoluminal, 238
perivisceral, 238
Endothelial cells, vascular
response to surgery, 314, 317
in wound healing, 324
Endothelins, 317
Endotoxin, 33
gut-derived, 126, 127
Endotracheal intubation
in critical illness, 395
postoperative, 355
in resuscitation room, 4, 13
Endpoints see Outcomes
Energy requirements, 127-128
Energy transfer
blast injuries, 21
penetrating trauma, 20
Enflurane, 176, 177
Enteral nutrition, 128-129, 321
complications, 129
in critical illness, 395-396
diets, 128, 396
indications, 126, 126-127
postoperative, 352
route of administration, 128-129
Enterococci, glycopeptide-resistant
(GRE), 207
Environmental factors, in cancer
pathogenesis, 262
Epidermal cells
cultured, to aid healing, 247-248
in wound healing, 245, 323-324
Epidermal growth factor (EGF), 323, 326
Epidermal growth factor receptor
(EGFR) inhibitors, 294, 295
Epidural abscess, 365
Epidural anaesthesia/analgesia, 180, 181
in cancer pain, 409
complications, 355, 364-365
mechanisms of action, 358, 358
patient-controlled (PCEA), 364
postoperative pain control, 351,
364-365
thromboprophylaxis and, 167, 365
Epidural haematoma, 1 67, 364—365
Epilepsy, 15, 77
Epinephrine see Adrenaline
Epineurium, 27, 341
Epipodophylotoxins, 287
Epstein-Barr virus (EBV), 262
Errors, 228-229
of judgement, 228 229
systems, 229
type I and type II, 449
see also Adverse incidents
Erythropoietin, 398
in cancer, 294
preoperative therapy, 90, 91, 95
in renal failure, 400
Escharotomy, 43
Escherichia coli, 207
Ether (diethyl ether), 173, 176, 176
Ethical issues
audit, 433
organ transplantation, 254-255
Ethics committees, research, 161
Ethylene oxide (EO), 211-212
Etomidate, 174, 175
Eusol, 200
Evidence-based practice (EBP), 138-143,
454
barriers to, 141-142
definition, 138
examples, 139, 140
fears about, 139-140
implementation, 140-142
Examination, clinical see Clinical
examination
Exercise, 344
Experience, 146, 150
Exposure, in primary survey, 8
External fixation, 347
Extracellular fluid (ECF), 107, 108, 108,
109
expansion, 114, 115
losses, 113-115, 114, 115
Extradural haematoma (EDH), 23, 37, 37
Extravasation, cytotoxic drugs, 290
Exudate
inflammatory, 323
wound, 200, 235
Eye
mustard gas exposure, 17
protection/ visors, 189, 190, 209
Facial skeleton, 24
fractures, 23-25
middle third fractures, 24, 24
Factor Vila, recombinant, 100
Factor VIII preparations, 75, 100
Factor IX preparations, 75, 100
Faecal occult blood testing, 424-425
Fagan's nomogram, 446-447, 447
Falls, from a height, 19, 20
Familial adenomatous polyposis (FAP,
adenomatous polyposis coli,
APC), 262, 420-421, 421
Family see Relatives
Family history, 418, 418
Farnesyl transferase inhibitors, 294
Fascia, 334
Fasting, preoperative, 166, 166
Fat embolism syndrome, 41-42, 42
Fat metabolism
after surgery, 315, 319
response to injury, 30, 31
Fatty acids, non-esterified (NEFA), 30, 31
Fc receptors, 84
Fear, 314
FEIBA, 100
Fentanyl, 407
in anaesthesia, 175, 178
in chronic and terminal illness, 406
postoperative analgesia, 362
Ferritin, serum, 91
Fetal skin, wound healing, 242, 245
FEVj/FVC ratio, 170
Fever, postoperative, 355-356
Fibre optics, 190-192, 191
see also Endoscopes
Fibrin, 323
Fibrin glue, 204-205
Fibrinogen, 323
concentrate, 100
in cryoprecipitate, 99
Fibroblast growth factor (FGF), 244
Fibroblasts, 204
in malignant disease, 261
in wound healing, 245, 324
Fibronectin, 323, 325
Field blocks, 180, 181
Fight or flight response, 29-30, 314
Filograstin, 294
Fine needle aspiration, 58, 266
Fire hazards, operating theatres, 187,
190
Flail chest, 4, 22
Haps, 247
fascial, 247
free, 247
in malignant disease, 269
myocutaneous, 247
Flow cytometry, 84-85
Flow phase, response to trauma, 29,
31-32
Fluid
challenge, 112, 113, 389-390
compartments, 107-109
water movement between, 109
excess, 114, 115
interstitial, 107
losses, 111-114, 115
requirements, postoperative, 352
retention, postoperative, 318
third space losses, 318
see also Body fluids; Extracellular fluid;
Intracellular fluid
482
INDEX
Fluid balance, 109-110, 110
charts, 111, 351
effects of surgery, 318
intraoperative, 118-119
postoperative, 350, 351-352
see also Dehydration; Hypovolemia
Fluid management, 110-119
assessment of deficits, 112-114
basal regimens, 110, 111
in burn injury, 43
choice of fluids, 114-115
in continuing loss, 111
in dehydration, 111-112
in hypotension, 391, 391
intraoperative, 118-119
postoperative, 350, 351-352
in renal dysfunction, 395
in resuscitation, 6
in terminal illness, 410
Flumazenil, 354
Fluoroscopic imaging, 60, 196
5-Fluorouracil (5FU), 291, 296, 297
Focused abdominal sonography in
trauma (FAST), 60
Folic acid supplements, 90, 105
Folinic acid, 291
Footwear, theatre, 209
Foreign bodies, wound healing and,
329
Forensic issues, A & E department, 13,
16
Forest plot, 451, 451-152
Formative assessment, 467
Fractional cell killing, 286
Fractionation, 272
Fractures, 39
blood loss, 27
bone revascularization, 346
fat embolism syndrome, 41
fixation, 346-347
healing, 39, 327-328, 346
intra-articular, 340
limb, 27
non-union, 328
pathological, 39
stress, 39
see also specific fractures
Fresh frozen plasma (FFP), 98-99
indications, 99, 104, 105
in massive transfusion, 104, 118
Frostbite, 243-244
Functional status, intensive care and, 388
Furosemide (frusemide), 395
Gait, 342, 342
cycle, 343
limping, causes, 342
Gallbladder trauma, 25
'y-irradiation
radiotherapy, 271, 272
sterilization, 201,212
Gastric acid, 82
Gastric cancer, 262, 265, 296
screening, 425, 426
spread, 268
Gastric contents, aspiration, 13, 176, 356
Gastric emptying, delayed, 356
Gastric secretions, replacing losses, 115,
115
Gastritis, atrophic, 87
Gastrografin, 60, 384
Gastrointestinal cancer, 265
non-surgical management, 296-207
palliative surgery, 268
spread, 266-267
tumour markers, 304-305
see also specific types
Gastrointestinal haemorrhage, 14
Gastrointestinal surgery
anastomotic leakage, 384
lasers, 189
postoperative infections, 381-382
upper, preoperative preparation, 169
see also Abdominal surgery
Gastrointestinal tract
bacterial translocation, 126, 127, 318
chemotherapy side-effects, 291
decontamination, in septic shock, 383
effects of surgery, 318
radiation side-effects, 280, 281
Gastrostomy, percutaneous endoscopic,
128-129
Gelatin solutions, 100, 116, 117
Gelofusin, 116, 117
Gene(s), 259, 417
damage, in cancer pathogenesis,
262-263
upregulation of transcription, 317
General anaesthesia, 174-179
induction, 174-176
maintenance, 176-178
recovery, 178-179
Gene therapy, for cancer, 295
Genetic disorders, 417
assessment and management, 418-420
family history, 418, 418
Genetics, 417-122
basic concepts and terminology,
417-118
cancer susceptibility, 262, 417, 420,
420-122
mechanisms of cancer pathogenesis,
262-263, 420
Genitourinary system, trauma, 25-26
Genomic instability, 284
Gentamicin, 376
Germ cells, 417
Germ cell tumours, 299, 303-304, 304
Gestalt, 144
Gestational trophoblastic rumours
(GTT), 303
Gibbs-Donnan effect, 108
Glasgow Coma Scale, 35, 36
Gleevec (STI-571), 294, 295
Gloves, 200, 209
holes, 209, 219
Gloving, double, 209, 219
Glucagon, 31-32, 315-316
Glucocorticoids
response to injury, 30, 315, 317
wound healing and, 329
see also Corticosteroid (steroid)
therapy
Gluconeogenesis, 31 9
Glucose
blood
perioperative control, 74
response to injury, 30, 315
in resuscitation, 13
metabolism, in response to injury, 30,
31, 319
solutions, 111, 117
Glucose-6-phosphate dehydrogenase
(G6FD) deficiency, 92, 135
Glues, tissue, 204-205, 205, 234
Glue sniffing, 78
Glutamine, 319, 321
Glutaraldehyde, 201, 211, 212
Glycogen, 319
Glycopeptide-resistant enterococci
(GRE), 207
Glycopyrrolate, 173, 174, 179, 412
Goitre, retrosternal, 170
'Golden hour/ 18-19
Gonadal damage, cancer therapy, 280,
292
Good surgical practice, 225-229
Goserelin, 292, 293
Gowns, 199, 208
alternative materials, 200, 208
Charnley exhaust, 200, 208
disposable non-woven fabric, 184, 200,
208
Graduated compression stockings
(GCS), 167, 451, 451-452
Graft rejection see Rejection, graft
Graft versus host disease (GVHD), 88,
103
Gram-negative bacteria, antibiotic-
resistant, 207
Granulation tissue, 245, 324
in fracture healing, 327
Granulocyte colony stimulating factor
(G-CSF), 294
Grey Turner's sign, 26
Groshong catheters, 289
Ground substance, 332
Growth factor receptor inhibitors, 294,
294-295
Growth factors, 294
in cancer pathogenesis, 260, 260-261
cell cycle control, 259, 260
in wound healing, 325-326, 327
Growth hormone, 71-72, 316
Growth plate (physis), 343
Guedel airway 4
Guidelines, 148, 435
Gunshot injuries, 20, 22, 38
Gynaecological cancer, 298
Gynaecological surgery, 189, 379
H 2 antagonists, 396
Haemaccel, 116, 117
Haemarthrosis, 336
Haematocrit (Hct), in fluid loss/excess,
114, 114, 115
483
INDEX
Haematogenous spread, cancer, 268
Haematological assessment
intraoperative/ 103-105
postoperative, 105
preoperative, 90-93
Haematological changes, in response to
surgery, 320
Haematological disorders, 74-75,
90-106
Haematology, 57
Haematoma, 19, 242
fracture, 346
spinal epidural, 167, 364-365
wound, 386
Haemodialysis, 398-399, 400, 400
Haemodilution, acute normovolaemic
(ANH), 94-95, 103
Haemofiltration, 399, 400
Haemoglobin (Hb)
C disease, 75
concentration, 121
postoperative, 105
preoperative, 74-75, 91, 97-98
fetal, 12
oxygen binding, 12, 13
SC disease, 75, 92
sickle (HbS), 75, 92
Haemoglobinopathies, 75, 92, 419
Haemolytic transfusion reactions (HTR),
101
Haemophilia, 75
Haemorrhage/bleeding
in bone marrow failure, 290-291
in cardiopulmonary bypass (CPB),
105
cardiovascular response, 32, 112
control see Haemostasis
fractures, 327
intraoperative, 103-105
metabolic response, 30
postoperative, 386
preoperative management, 95
primary survey, 5
see also Blood loss
Haemostasis
in minimal access surgery, 239
postoperative bleeding, 386
in wound healing, 322, 323
Haemostatic agents, 202
Haemothorax, 22
Hair
preoperative removal, 166, 210, 230,
382
tying up /covering, 209
Haloperidol, 412
Halothane, 176, 176-177
hepatitis, 177
Halsted, William, 235, 267, 332
Handwashing, 207
before surgery (scrubbing up), 200,
210
Hartmann's solution (Ringer's lactate),
111, 117, 118
Hazard ratio, 449
hCG see Human chorionic
gonadotrophin
Head injury, 15, 22-23
pathophysiology, 34-37
resuscitation, 4, 13
Health, surgeon's, 228
Healthcare workers
infected with blood-borne viruses,
220-221
risks of nosocomial virus
transmission, 215-222
see also Surgeons
Health Improvement Programmes
(HimPs), 440
Heart
transplantation, 79, 253-254, 255
traumatic injury, 22
Heart and lung transplantation, 254
Heart block, 69
Heart disease
congenital, 66-67
cytotoxic drug-induced, 291
postoperative care, 350
preoperative risk assessment, 167, 168
valvular, 67^68, 374
see also Coronary artery disease
Heart failure, 14, 66
congestive (CCF), 65, 66
Heart rate, 389
response to surgery, 318
in trauma, 30
Heart surgery, open, 104-105
Heat loss, minimizing, 184
Heat shock pToteins (HSPs), 316
Helsinki Declaration, 161
Henderson-Hasselbalch equation, 120,
121
Henry, A.K., 335
Heparin, 93
epidural analgesia and, 365
-induced thrombocytopenia (HIT), 93,
98
low molecular weight see Low
molecular weight heparin
neutralization, 105
for thromboprophylaxis, 167, 380
in venous thromboembolism, 380
for warfarin-treated patients, 165
Hepatic failure, 15
Hepatitis B virus (HBV), 215, 216, 262
immunization, 217, 218-219, 220
infected healthcare workers, 220-221
occupational risk, 217
postexposure prophylaxis, 220
reducing occupational risk, 218-220
sources of infection, 217
testing, 54, 218
transfusion-related transmission, 102,
377
Hepatitis C virus (HCV), 215, 216-217
infected healthcare workers, 221
occupational risk, 217
postexposure prophylaxis, 220
reducing occupational risk, 218-220
sources of infection, 217
testing, 54, 218
transfusion-related transmission, 102,
377
Hepatocellular carcinoma (HCC), 262,
307
Hepatorenal syndrome, 169, 378
Herceptin, 291, 294, 294-295
Hereditary non-polyposis colon cancer
(HNPCC), 418, 421,422
Hernia, incisional, 385
Heroin overdose, 15
Hetastarch (hydroxyethyl starch, HES),
100, 116, 117
Hexachlorophane, 210
Hextend, 117
Hickman catheters, 289
High dependency unit (HDU), 168
referral algorithm, 382
see also Intensive care
High-risk surgery, 167-168
Histamine, 175,317
Histopathology, 58
History, clinical, 49-51, 459
general assessment, 50-51
presenting complaint, 50
HIV infection/ AIDS, 78-79, 87, 215-216,
263
in healthcare workers, 220-221
occupational risk, 79, 217, 217
postexposure prophylaxis, 220
reducing occupational risk, 218-220
sources of infection, 217
testing, 54, 218
transfusion-related transmission, 102,
377
HLA (human leucocyte antigen, MHC),
85-86, 250
matching, 88, 250-251
Hodgkin's disease, 292, 298
Hoffman elimination, 178
Hormonal anticancer therapy, 292-293,
293
Hormone replacement therapy, 165
Hospital episode statistics (HES), 465
Hospital information systems, 434, 465
Hospital Transfusion Committee (HTC),
96
Hospital transfusion laboratory, 96
Hounsfield units (HU), 61
Hubris, 227
Hudson mask, 393
Human chorionic gonadotrophin (hCG),
303-304, 304
Human factor analysis, 433
Human immunodeficiency virus
infection see HIV infection /AIDS
Human plasma protein fraction (HPPF),
115, 116
Humidity, operating theatre, 184
Hydatidiform mole, 303
Hydrocolloid dressings, 200, 235
Hydrocortisone, 71, 72, 80, 376
Hydrogel dressings, 235
Hydrogen ions (H + ), 119
concentration, 119, 119
production and elimination, 10, 11
Hydromorphone, 406, 407
Hydroxybutyrate dehydrogenase (HBD),
303
484
INDEX
Hydroxyethyl starch (HES), 100, 116, 117
5-Hydroxyindoleacetic acid (5HIAA),
308
5-Hydroxytryptamine (5HT), 316
Hyoscine
premedication, 173, 174
in terminal illness, 412, 413
Hypercapnia (hypercarbia), 314, 393
intracranial pressure effects, 35
management in resuscitation, 4
Hyper fractionation, 275
Hyperglycaemia, 15, 30, 319
Hyperkalemia, 110
in crush syndrome, 41
dialysis, 400
suxamethonium-induced, 175
Hypermetabolic state, 31-32
after surgery, 318-319
energy and nitrogen requirements,
127-128
Hyperparathyroidism, secondary, 401
Hypersensitivity reactions
antibiotics, 375
blood transfusion, 101
Hypertension, 66
in phaeochromocytoma, 72
postoperative, 355
in renal disease, 76
risks of surgery, 374
Hyperthermia, malignant, 175, 419
Hyperthyroidism (thyrotoxicosis), 71,
170
Hypertrophic scars, 234, 245, 329,
385-386
Hyperventilation, 10, 120
Hypnosis, during anaesthesia, 174, 176
Hypocalcaemia, 15
Hypofibrinogenaemia, 99
Hypoglycaemia, 13, 15, 314
Hyponatremia, 15, 318
Hypopituitarism, 71
Hypotension, 391
epidural analgesia-associated, 355,
364
in hypovolemia, 112
management, 391, 391
postoperative, 355
in shock, 5, 390
Hypothalamic-piruitary-adrenal (HPA)
axis, response to surgery, 314, 315,
317
Hypothermia
in massive transfusion, 104
resuscitation, 9, 15
Hypothesis, 455
testing, 452
Hypothetico-deductive approach, 49
Hypothyroidism, 71
Hypoventilation, 4, 5, 393
Hypovolemia, 109
assessment, 5, 112-113
cardiovascular response, 32
management, 114-117
monitoring, 8-10
postoperative, 352
renal dysfunction, 395
response to surgery and, 314, 321
resuscitation, 5-6
water and electrolyte replacement,
114-115
Hypovolemic shock, 14, 390
in burn injury, 42-43
pathophysiology, 32
Hypoxia /hypoxaemia, 314, 393-394
head injury and, 35
postoperative, 318, 349, 367
risk factors, 374, 375
spinal cord injury and, 38
Hypoxic ventilatory drive, 5, 393
IgA, 84, 85
IgD, 84
IgE, 84
IgG,84
IgM,84
Ileostomy, 169
Ilizarov, Gavril, 348
Image-guided surgery, 62, 62-63
Image intensifiers, 196
Imaging (radiology), 58, 59-63
cancer staging, 266
interventional techniques, 62, 196
role in surgery, 61-63
safety, 60, 60
techniques, 59-61
Immobility, in terminal illness, 409
Immobilization
joint, 335
muscles, 333
Immunity, 82-89
adaptive, 83-87
antibody-mediated, 83-85
cancer, 88
cell-mediated, 85-87
effects of surgery, 320
innate, 82-83
transfusion-induced suppression, 103,
377
transplantation, 87-88, 250
Immunodeficiencies
acquired, 83, 85, 87
B cell, 85
combined T and B cell, 87
iatrogenic, 83, 85
primary, 83
Immunoglobulin, 83
gene rearrangements, 83
intravenous, 100
isotypes, 84
preparations for infusion, 100
structure, 84, 84
see also Antibodies
Immunohistochemistry, 266
Immunosuppressive therapy, 79, 87
cancer risk, 88
side-effects, 252
transplant recipients, 88, 251-252
Immunotherapy, cancer, 88
Implant materials, 203-204
infection risk, 203
tissue response, 204
Implants, orthopaedic, 346-347
Incident review, 430
Incidents, adverse see Adverse incidents
Incisional hernia, 385
Incisions, 230-233
chest, 233
closure see Closure
internervous planes, 342
laparotomy, 232, 232-233
in muscle, 332-333
preoperative marking, 166
principles, 231
Index Medicus, 457
Induction of anaesthesia, 1 74-1 76
crash, 175-176
relaxation at, 175
Infections
in antibody deficiencies, 85
audit, 213
burn injuries, 43
endogenous transfer, 210
epidural analgesia-associated, 364
hospital acquired (nosocomial), 206,
207
in immunodeficiencies, 83
overwhelming postsplenectomy, 85
postoperative, 355-356, 381-383
in diabetes, 375
in obstructive jaundice, 377-378
risk factors, 381-382
treatment, 382
see also Wound infections
prevention, 206-214, 382-383
asepsis and antisepsis, 208-212
control of resistant organisms,
207-208
feedback, 213
in intensive care, 396
in orthopaedic surgery, 184, 199-200
prophylactic antibiotics, 212-213
surgical technique, 212
prosthetic surgery risk, 203
response to surgery and, 313-314
surgical access and, 231
surveillance, 213
in T cell deficiency, 86-87
testing for, 54
transfusion-transmitted, 99, 102, 102,
377
wound see Wound infections
wound healing and, 329
see also Sepsis
Inferior vena cava, traumatic injury, 26
Infertility, in cancer patients, 280, 292
Inflammatory joint disease, 336-337
Inflammatory response, 244-245, 322,
323-324
fractures, 39, 327
implant materials, 204
Information
availability, 457
breaking bad news, 460—462
confidentiality, 162-163
in decision making, 145
for evidence-based practice, 142
for informed consent, 156, 157-158
485
INDEX
Information (cont.)
for postoperative patients, 354
for surgical logbook, 463-464
withholding, 461
Information systems, hospital, 434, 465
Inhalational injury, 4, 44
Inheritance, Mendelian, 418
Inhibitor of kappa B kinase/ nuclear
factor kappa B (IKK/NF kappa B)
proteins, 317
Injury Severity Score (ISS), 45
Innate immunity, 82-83
deficiencies, 83
Inoculation (needlestick) injuries
management, 219-220
prevention, 209, 218, 219
Inotropes, 391
Instruments, 201
cleaning and disinfection, 210-211
precautions against loss, 233-234
sets, 201
sharp see Sharp instruments
sterilization, 201, 211
transmissible spongiform
encephalopathy (TSE)-
contaminated, 211
Insulin
Actrapid, 74
resistance, in trauma, 30, 31
response to surgery, 315, 319
therapy, 73, 74
Insulin analogues, 73
Insulin-like growth factor (IGF), 244,
245
Insurance companies, 432
Integrin receptors, 323
Integrins, 261
Integrity, 228
Intensive care, 388-397
acute neurological problems, 395
cardiovascular pathophysiology,
389-391
decision making, 388-389
general aspects, 396
nutrition, 395-396
organization, 388
referral algorithm, 382
renal dysfunction, 394^395
respiratory pathophysiology, 391-394
Intensive care unit (ICU), 168, 388
'Intention-to-treat' analysis, 448
Intercollegiate Examinations Board, 472
Intercollegiate specialty examinations,
472-^74
format, 473-474
outcome, 474
Interferon-a (IFNa), 220, 294, 298
Interferon-7, 316
Interferons, 316
Interleukin 1 (IL-1), 316, 317, 326, 327
Interleukin 2 (IL-2), 294, 316
Interleukin 6 (IL-6), 30, 33, 316, 317
Interleukin 10 (IL-10), 30
Interleukins, 86
Intermittent pneumatic calf
compression, 167, 380
Intermittent positive pressure
ventilation, in asthma, 70
Internal jugular vein, cannulation, 5-6
International normalized ratio (INR), 93
Internervous planes, 342
Interstitial fluid, 107
Interventional radiology, 62, 196
Intestinal transplantation, 254
Intracellular fluid (ICF), 107, 108, 109
in fluid loss/ excess, 114, 115
Intracellular pathogens, 86-87
Intracerebral haematoma (ICH), 37
Intracranial haematoma
acute traumatic, 23, 37
posterior fossa, 36
Intracranial pressure (ICP), 35
raised, 35, 408
Intradural haematoma (IDH), acute, 37
Intramedullary nails, 347
Intramucosal pH (pHi), gut, 113
Intraoperative assessment,
haematological, 103-105
Intraosseous infusion, 5
Intraventricular conduction defects, 69
Invasive diagnostic procedures, 58
Investigations, 51, 52, 53-58
acceptability, 55
aims, 53-54
availability, 55
complications, 56
cost, 55, 443
limitations, 55-56
in practice, 57-58
preoperative, 166
protocols, 57
routine, 55
safety, 55
selection, 54-55
sensitivity, 54-55
sequence and timing, 56-57
simplicity, 55
specificity, 54-55
urgency, 56-57
Iodine-131 therapy, 280
Iressa, 294, 295
Iron
deficiency, 91, 92, 98
overload, 103
supplements, 90, 91, 98, 105
toxicity, 16
Ischaemia
muscle, 333
tourniquet, 342
Ischaemic heart disease see Coronary
artery disease
Isoflurane, 176,177
Isolation, 'wound and enteric'/ 'source,'
208
Isoprenaline, 69
Isotype switching, 84
Jaundice, 169
obstructive, 377-378
Jehovah's Witnesses, 160, 161, 163
Jejunostomy, needle catheter, 128-129
Joint(s), 337-340
articular cartilage, 338-339
axes, 337, 337
classification, 338
immobilization, 335
inflammatory disease, 336-337
intra-articular surgery, 238
menisci, 338-339
pain, 408
synovial see Synovial joints
Joint replacement surgery, 171, 203
bone cement, 204, 348
infectious complications, 203, 379
tissue response to foreign materials,
204
Journals, 454, 455
Kallikreins, 316
Kaplan-Meier survival curves, 450
Karaya gum, 204
Keloids, 234, 245, 329, 385-386
Keratinocyte growth factor (KGF), 244,
323
Keratinocytes, in wound healing, 323
Ketamine, 174, 175
Kidneys
in acid-base balance, 120
transplantation, 249, 252-253, 255,
377
trauma, 26
Killer inhibitory receptors (KIRs), 83
Kinins, 316
Knife wounds, 20
Knowledge, tacit, 150
Knudson's two-hit hypothesis, 263, 263,
420
Lacerations, 243
Lactate dehydrogenase (LDH), 303, 304
Lamivudine, 220
Langerhans cells, 83
Langer's lines, 231, 234, 242
Laparoscopic surgery, 237
cholecystectomy, 239, 378-379
diathermy, 188, 379
economic aspects, 239, 443
hand-assisted, 379
limitations, 239
preoperative preparation, 169
vs open surgery, 238
see also Minimal access surgery
Laparoscopic ultrasound, 239
Laparoscopy diagnostic, 58
Laparotomy
diagnostic, 58
incisions, 232, 232-233
vs laparoscopic surgery, 238
Large bowel
surgery, preoperative preparation,
169
trauma, 26
Lasers, 188-190
classification, 189
clinical applications, 189
486
INDEX
r : -™^ :aj i"'
hazards, 189-190
safety measures, 190
types, 188-189
Latex allergy, 171,209
Law of Tension Stress, 348
Lead time bias, 423, 456
Learning, lifelong, 439
Le Fort fractures, 24, 24
Left bundle branch block, 69
Left ventricular function, assessment
112-113
Leg ulcers, chronic, 329
Length bias, screening, 423
Leucocytosis, postoperative, 320
Leucodepletion of blood products,
93-94, 97, 102
Leucotrienes, 316
Leucovorin, calcium (folinic acid), 291
Leukaemia
biological therapy, 294, 295
cytotoxic drug-induced, 292
radiation-induced, 281-282
Levobupivacaine, 180, 181, 364
Levodopa, 80
Levomepromazine, 412
Lidocaine (lignocaine), 180, 181
maximum dose, 353, 363
overdose, 16
Li-Fraumeni syndrome, 421
Ligaments, 334-335
Ligatures, 201-202
Likelihood ratio (LR), 44^-447
Limbs
compartments, 28, 334, 335
incisions, 231
trauma, 27-28
Limp, causes, 342
Linear accelerators, 271, 271
Lipid metabolism see Fat metabolism
Literature, critical reading, 454^457
Liver
capsule pain, 408
glucose production, 31
injury, 25
metastases, 268
surgery, preoperative preparation,
169-170
transplantation, 254, 255
Liver disease, 15, 76-77
cancer chemotherapy, 289
drug prescribing, 135
haematological assessment, 105
Living wills, 160
Local anaesthesia, 180-181
daycase surgery, 353-354
Local anaesthetic (LA) agents, 180, 181
epidural analgesia, 364
maximum doses, 353, 363
postoperative analgesia, 363-365, 366
sites of action, 358, 358
toxicity, 353-354, 363
Logbook, surgical, 463-465
data analysis, 465
information required, 463-464
problems, 464-465
rationale, 463
Logic, scientific, 454-455
Log-roll, 8
Lorazepam, 173
Low molecular weight heparin
(LMWH), 93
epidural analgesia and, 365
thromboprophylaxis, 167, 380
in venous thromboembolism, 380
Lung(s)
in acid-base balance, 120
inhalational injury, 44
resection, 170
response to surgery, 318
toxicity of chemotherapy, 291-292
trauma, 21-22
Lung cancer, 265, 279, 296
Lung function tests, 170
Luteinizing hormone releasing hormone
(LHRH) analogues, 292, 293, 293
Lyell's syndrome, 242
Lymphatic drainage
cancer, 267
radiation side-effects, 281
Lymph nodes
elective dissection (ELND), 267
enlarged, 51
irradiation, 278
metastases, 267, 268
sentinel, 267-268
Lymphocyte count, 125
Lymphoedema, 281, 408
Lymphoma, 298
Lysozyme, 82
Macrophages, 82-83, 86
in fracture healing, 327
in wound healing, 244-245, 324, 326
Magnetic resonance imaging (MRI), 61
interventional, 62
intraoperative, 62-63
Maintenance of anaesthesia, 176-178
Major histocompatibility complex
(MHC), 85-86, 250
class I, 85-86
class II, 86
see also HLA
Malaria, 15, 102
Malignant disease see Cancer
Malignant hyperthermia, 175, 419
Malnutrition, 314
detection, 125
immune effects, 87
protein-energy (PEM), 125
wound healing, 328
see also Nutritional support
Mammography, screening, 425
Mandibular fractures, 24-25, 25
Manometry, 58
Marfan's syndrome, 332, 419
Masks, face, 184, 208-209
Mastectomy, 267, 269
Matrix metalloproteinases (MMPs), 261
Maxillofacial fractures, 23-25
Mean arterial pressure (MAP), 35
Mean cell haemoglobin (MCH), 91, 92
Mean cell volume (MCV), 91, 92
Mechanical ventilation see Assisted
ventilation
Medawar, Sir Peter, 49
Mediastinal trauma, 22
Medical Education Standards Board, 440
MEDLINE, 450, 451, 457
Medroxyprogesterone acetate, 292, 293
Megestrol acetate, 292
Melanoma, malignant, 267-268, 298
biological therapy, 294
tumour markers, 308
Mendelian inheritance, 418
Meninges, 23, 23
Menisci, 338-339
Mental handicap, consent in, 159
6-Mercaptopurine, 251
Mesenteric embolism, 14
Mesorectal excision, total, 267
Meta-analysis, 138, 450-452, 451
Metabolic acidosis, 10, 11, 119
dialysis, 400
postoperative, 318
secondary or compensatory, 119
treatment, 123
Metabolic alkalosis, 10, 11, 119
Metabolic rate, 31, 318-319, 319
Metabolic response to injury, 29, 29-32,
125
in diabetic patients, 375
ebb phase, 29-31
flow phase, 31-32
necrobiotic phase, 29, 30-31
in surgical patients, 315, 318-320
Metaphyseal arteries, 346
Metaphysis, 343
Metastasis, tumour, 261, 261-262
Metformin, 73
Methadone, 406, 407
Methicillin-resistant Staphylococcus
aureus (MRSA), 54, 207-208, 375
Methionine, 328
Methods, study, 447-448
Methotrexate, 291
Methylprednisolone, 72
Microbiology, 57-58
Micrometastases, 284
Microscopes, operating, 196-197
Microsurgical instruments, 197
Microwave ablation techniques, 194
Midazolam, 173, 173, 174, 175
daycase surgery, 354
in terminal illness, 412, 413
Minimal access surgery, 237-240
boundaries, 237-238
cost effectiveness, 239, 443
future, 240
limitations, 238-239
postoperative complications, 378-379,
380
training, 239-240
see also Laparoscopic surgery
Minimal Access Therapy Training Unit
(MATTU), 239
Minimum alveolar concentration
(MAC), 176
487
INDEX
Missile injuries, 20
Mitral stenosis, 67
Mobility, wound healing and, 329
Mobilization, pain and, 359
Mobitz type 1 (Wenckebach) heart block,
69
Mobitz type 2 heart block, 69
Monitoring
after initial resuscitation, 8-13
postoperative analgesia, 366-368
recovery phase, 349-350
Monoamine oxidase inhibitors, 78, 80
Monoclonal antibodies, 84-85
radiolabeled, 88
therapeutic use, 88
Monocyte chemoattractant protein 1,
323
Monocytes, 326
Moral rights, 155
Morbidity and mortality meetings,
431^32
Morphine
in chronic and terminal illness,
406-107
postoperative analgesia, 179
premedication, 173
routes of administration, 361, 362
side-effects, 408
Mortality, personal records, 464
Motor vehicle accidents see Road traffic
accidents
Moynihan, Lord, 235
MRCS examination, 466-471
assessments, standards and marking,
467-468
future developments, 471
overview, 468
requirements, 466—167, 467
sections, 468-471
MRSA (methicillin-resistant
Staphylococcus aureus), 54,
207-208, 375
Mucopolysaccharidoses, 419
Multidrug resistance (MDR) gene, 288
Multifactorial diseases, 417
Multiple choice question (MCQ) papers,
MRCS examination, 467, 468^69,
469
Multiple organ failure (MOF), 19, 33-34,
320, 390
pathophysiology, 33, 126, 127
postoperative, 383
renal failure, 395
survival rates, 383
Multiple sclerosis, 77
Muscle
denervation, 333
genetic disorders, 419
healing, 332, 333
immobilization, 333
incisions, 332-333
ischaemia, 333
response to trauma, 31, 319-320,
332-333
spasm, 408
weakness, in terminal illness, 409
Muscle relaxants, 175, 176, 177
depolarizing, 175, 177
non-depolarizing, 177, 178
Muscle relaxation, reversal, 178-179
Muscle wasting, 31
Mustard gas, 17
Mutations, 259, 284, 417
in cancer pathogenesis, 263, 263, 420
Myasthenia gravis, 77-78
Myelin, 340
Myeloma, multiple, 84, 298, 308
Myelosuppression see Bone marrow
failure
Myocardial contractility, 390
Myocardial infarction
in diabetes, 73
perioperative, 66
prior, 170-171, 374, 374
risk factors, 374-375
Myocardial ischaemia, perioperative, 65,
66
Myofascial pain, 405, 408
Myofibroblasts, 42, 245, 324, 325
Myoglobinuria, 13, 41
Myotonic dystrophy, 419
Myxoedema, 15
Nails, intramedullary, 347
Naloxone, 8, 361, 364
Nasal cannulae, 393
Nasoethmoidal-orbital fractures, 23-24
Nasogastric tube feeding, 128
Nasogastric tubes, 8, 352-353
Nasojejunal tube feeding, 396
Nasopharyngeal airway, 4
National Blood Authority (NBA), 95
National Centre for Clinical Audit
(NCCA), 430
National Confidential Enquiry into
Perioperative Deaths (NCEPOD),
64, 168, 431
National Institute for Clinical Excellence
(NICE), 133, 148, 439
National Performance Assessment
Programme, 440
National Prescribing Centre (NPC), 133
National Service Frameworks (NSFs),
439, 440
Natural killer (NK) cells, 83
Nausea and vomiting
chemotherapy-induced, 291
in chronic and terminal illness,
410-411, 411, 412, 412
opioid -induced, 408
postoperative (PONV), 368, 368
Near misses see Adverse incidents
Necrobiosis, in trauma, 29, 30-31
Needles, suture, 202
Needles tick injuries see Inoculation
injuries
Negative predictive value (NPV), 424,
446
Negative pressure, topical, 200
Negligence, 157-158
claims, 229
Neianavir, 220
Neoadjuvant therapy, 269, 288
Neodymium, yttrium, aluminium garnet
(NdYAG) laser, 188, 189
Neonates
risks of surgery, 373
screening, 426
Neostigmine, 179
Nephrotic syndrome, 76
Nerve, peripheral see Peripheral nerve
Nerve blocks, 180, 181, 409
Nerve fibres, types, 180, 180
Nerve gases, 17
Nerve injuries, 27
classification, 340, 341
healing, 39-41, 328
surgical patients, 185, 340-342
surgical repair, 342
Nerve pain, 405, 408
Nervous tissue, 340-342
healing, 328
Neurapraxia, 40, 341
Neuroblastoma, 308
Neurofibromatosis, 421
Neurogenic shock, 14, 32-33
Neurological assessment, 8
Neurological disease, 77-78
Neurological problems, acute, 395
Neuroma, 40, 328
Neuromuscular blockade, reversal,
178-179
Neuromuscular blockers see Muscle
relaxants
Neuron-specific enolase, 308
Neuropathy see Peripheral neuropathy
Neurosurgery, 185, 350
Neuro tmesis, 341
Neutropenia, 83, 290
Neutrophils (polymorph leucocytes),
82-83
in wound healing, 244-245, 323
New chemical entities (NCE), 131
New Injury Severity Score (NISS), 45
The New NHS: Modem, Dependable (1997),
435
New York Heart Association (NYHA)
classification, 167, 168
NHS Performance Framework, 440
NHS- wide clearing service (NWCS),
465
Nicotine, 70-71
Nitric oxide, 317
Nitrogen balance, 128
in response to injury, 31, 319
Nitrogen requirements, 127-128
Nitrous oxide, 176, 178
Non-haemolytic febrile transfusion
reaction (NHFTR), 101
Non-Hod gkin's lymphoma (NHL),
298
Non-seminomatous germ cell tumours
(NSGCT), 303-304
Non-steroidal anti-inflammatory drugs
(NSAIDs), 360-361
adverse effects, 178, 360
mechanisms of action, 358, 358
488
INDEX
postoperative analgesia/ 178, 179, 351 ,
366
preoperative medication, 90, 93, 173
Non-union, 328
Noonan syndrome, 419
Noradrenaline (norepinephrine), 314
Nosocomial infections, 206, 207
NSAIDs see Non-steroidal anti-
inflammatory drugs
Nuclear medicine, 61
Number needed to treat (NNT), 132, 448
Nuremburg Code, 161
Nutrient artery, long bones, 346
Nutrition
postoperative management, 352
wound healing and, 328-329
Nutritional assessment, 125, 165
Nutritional support, 125-130
in critical illness, 395-396
energy and nitrogen requirements,
127-128
monitoring, 128
postoperative, 127, 352
preoperative, 127, 165-166
response to surgery and, 320-321
selection of route, 126
in septic shock /septicaemia, 383
see also Enteral nutrition; Parenteral
nutrition
Nutritional support team, 130
Obesity, 74
morbid, 74, 374
risks of surgery, 373-374
Objective structured clinical examination
(OSCE), 468, 470
Octreotide, 170, 384, 412
Odds ratio (OR), 448^49
Oedema, in tissue injury, 323, 329
Oesophageal cancer, 265, 268, 269, 296
Oestrogen receptors (ER), 266, 292, 293,
295
Oliguria, 352, 395
Oncogenes, 259, 260, 418, 420
Oncogenesis, 263
Oncotic pressure, 107-108
Operating suit, 184
Operating tables, 184-185
Operating tent, 184
Operating theatres, 183-198
airflow, 183-184,199,209
clothing see Clothing, theatre
design and environment, 183-184
equipment, 184-197
management, 199-200
technique, 200
zones, 183
Ophthalmology, laser therapy, 189
Opioid receptors, 361
Opioids /opiates, 361-363
addiction, 78, 366, 408
anaesthetic supplementation, 178
in chronic and terminal illness, 406,
406-108
in elderly patients, 366
endogenous, 317
epidural, 364
equivalent doses, 407
fears of prescribing, 407-408
induction of anaesthesia, 175
mechanisms of action, 358, 358
poisoning, 8, 15
postoperative analgesia, 179, 366
premedication, 173, 173, 178
relative potency, 407
routes of administration, 361-362, 407
side-effects, 361, 367, 408
spinal (intrathecal), 365
tolerance, 366, 408
Opsonization, 82
Oral contraceptives, 80, 165
Oral hypoglycaemic drugs, 73
Orbit, blow-out fractures, 24
Orchiectomy, 267
Organ donors
availability, 254
cadaveric, 250, 251, 252
living related, 249, 250
living unrelated, 255
Organophosphate poisoning, 16, 17
Organ transplantation see
Transplantation
Oropharyngeal (Guedel) airway, 4
Orthopaedic surgery, 199
bone cement, 348
implant materials, 203
implants, 346-347
operating tables, 185
postoperative care, 350
postoperative complications, 379
preoperative preparation, 171
prevention of infection, 184, 199-200
in steroid-treated patients, 376
theatre clothing, 200, 208, 209
theatre management, 199-200
theatre ventilation systems, 199, 209
see also Joint replacement surgery;
Osteotomy
Osmolality, 108-109
plasma, 72
Osmotic pressure, colloid (COP),
107-108
Ossification
centres, 343
in fracture healing, 328
heterotopic, 333
Osteoarthritis, 171, 340, 344, 346
Osteoblasts, 327, 328, 343
Osteoclasts, 327, 344
Osteomalacia, 345
Osteoporosis, 72, 343, 345
Osteosarcoma, 269-270, 298
Osteotomy, 345, 346, 347-348
distraction, 347-348
healing after, 347
Otolaryngology, 189, 197
Outcomes (endpoints)
health care delivery, 430
randomized controlled trials, 448
reporting, 438
surrogate, 132
Ovarian cancer, 298
familial, 421, 421
impaired wound healing, 378
screening, 426
tumour markers, 305-306
Overseas, working, 226
Oxycel, 202
Oxycodone, 406
Oxygen, inspired (Fi0 2 ), 121, 393
Oxygen consumption (TO 2 ), 30
goals in high-risk surgery, 113, 168
in multiple organ failure, 34
Oxygen content of blood, 389
Oxygen delivery (D0 2 ), 30
goals in high-risk surgery, 113, 168
in multiple organ failure, 34
in shock, 32
Oxygen dissociation curve, 12, 13
Oxygen extraction ratio (OER), 30
Oxygen flux, 12
Oxygen saturation (0 2 sat.), 12,
120-121
in critical care, 394
postoperative monitoring, 350
Oxygen tension (partial pressure) see
Pa0 2 ; P0 2
Oxygen therapy, 393-394
methods of delivery, 393-394
postoperative, 349, 381, 393
in resuscitation, 4, 5
p53 suppressor gene, 261
Pacemakers, 69-70, 374
diathermy and, 70, 188
Packs, 202
PaC0 2 (PC0 2 ), 10, 10-11, 120, 121
in acid-base balance, 120, 122
correction, 123
postoperative monitoring, 350
in resuscitation, 4, 5
see also Hypercapnia
Paediatric formulary, 134
Paediatric patients see Children;
Neonates
Paget' s disease, 346
Pain
assessment, 367, 367
bone, 405, 408
breakthrough, 406
cancer, 405, 409
definition, 357
diagnosis of cause, 405
different operations, 359
incident, 406
mechanisms, 357
myofascial, 405, 408
nerve, 405, 408
opioid-resistant, 408-409
perception threshold, 357
postoperative, 357-369
psychological, 408-409
response to surgery and, 313
services, acute (APS), 182, 369
tolerance threshold, 357
visceral, 405
489
INDEX
Pain management
in chronic and terminal illness,
405-409
injection techniques, 409
postoperative,, 351, 357-369
see also Analgesia
Palliative care, 402
approach, 402
chemotherapy, 288
radiotherapy, 278-280
specialist, 402, 402
surgery, 268
symptom control, 404-412
Pancreas
endocrine disorders, 72-74
surgery, preoperative preparation,
169-170
transplantation, 253, 254
trauma, 25-26
Pancreatic cancer, 265, 268, 296, 378
Pancreatitis, 14
Pancuronium, 178
Pannus, 336-337
Pa0 2 , 12, 121
postoperative, 318, 350
in resuscitation, 4, 5
PA0 2 , 121
PA0 2 -Pa0 2 gradient, 121
Papaveretum, 173
Paracetamol, 179, 360
overdose, 15
Paracrine actions, 325
Paralytic (adynamic) ileus, 318, 356
Paramedian incisions, 232, 233
Paraproteins, 84, 308
Parasites, causing cancer, 263
Paratenon, 334
Paravertebral anaesthesia, 180, 181
Parenteral nutrition, 129-130
access, 129-130
central venous, 126, 129-130
complications, 130
in critical illness, 395-396
home, 130
indications, 126-127
monitoring, 130
nutrients, 130
peripheral (PPN), 126, 130
postoperative, 352
Partial response (PR), 290
Patient administration system (PAS),
434
Patient-controlled analgesia (PCA),
362
Patient-controlled epidural analgesia
(PCEA), 364
Patients
breaking bad news, 460-462
clinical governance perspective, 439
communication with, 459-460
participation in decision making,
145-146, 460
preparation for surgery see
Preoperative preparation
trust, 226
Patslide, 185
Pattern recognition, 52
PC0 2 see PaC0 2
Pedigree, 418
Pelvic fractures, 27, 27
Pelvic injuries, 26
Pelvic surgery, 378, 379
Penicillin allergy, 167
Penis, trauma to, 26
Peptic ulceration, prophylaxis, 396
Percutaneous transhepatic
cholangiography (PTC), 169
Perineal trauma, 26
Perineurium, 27
Periosteal arterioles, 346
Periosteum, 327, 345-346
Peripheral nerve, 340
injuries see Nerve injuries
mobilization, 340
structure and function, 27
Peripheral neuropathy
chemotherapy-induced, 291
in diabetes, 73, 342
Peripheral vascular disease, in diabetes,
375
Peritoneal cavity
cancer spread, 268
trauma, 25
Peritoneal dialysis, 400-401
principles, 398-399, 400
Peritonitis
peritoneal dialysis, 400^401
post-traumatic, 25
Perivisceral endoscopy, 238
Pethidine, 361, 362, 407
Peutz-Jeghers syndrome, 421
P-glycoprotein, 288
pH, 119, 119
arterial blood, 10, 10, 121
oxy haemoglobin dissociation and,
12,13
gut intramucosal (pHi), 113
Phaeochromocytoma, 72, 170
Phagocytes, 82-83, 244-245
Pharmacodynamic interactions, 136
Pharmacodynamics, 134
Pharmacokinetic interactions, 136
Pharmacokinetics, 134
Pharmacology, 131-137
Pharyngitis, bacterial, 210
Phenothiazines
overdose, 16
premedication, 173, 173
Phenoxybenzamine, 72, 170
Physiological assessment, 58
Physiotherapy, respiratory, 381
Pia mater, 23, 23
Pituitary gland disorders, 71-72
Placebo effect, 132, 454
Placental alkaline phosphatase (PLAP),
303
Plasma, 107
fresh frozen see Fresh frozen plasma
products, 99-100
virally inactivated, 99
Plasma osmolality, 72
Plasma volume, 109
expansion, 109, 117
quantification of loss, 113-114,
114
replacement/ substitutes, 100, 115-117,
116
Plastic surgery, 189
Plate fixation, bone, 346-347
Platelet-activating factor (PAF), 317
Platelet count, 92, 93, 103
Platelet-derived growth factor (PDGF),
244, 245, 323, 325
Platelet disorders, 75, 93, 93, 98
Platelets, in wound healing, 244,
323
Platelet transfusion, 98
indications, 98, 104, 105
Pleural effusion, 381
Pneumocystis carinii, 58
Pneumonia, postoperative, 318
Pneumothorax
complicating central venous
cannulation, 5, 6
postoperative, 355, 381
tension, 4, 14, 22
traumatic, 21-22
POi, 121
alveolar (PA0 2 ), 121
arterial blood see Pa0 2
Poiseuille, Jean, 5
Poisons, common, 15-16
Polyethylene, high density, 203
Polymethylmethacrylate (PMMA, acrylic
cement), 204, 348
Polypharmacy, 134
Polypropylene, 201, 204
Polytetrafluoroethylene (PTFE), 201, 203
Popper, Karl, 49, 455
Population, 449
Porphyria, 135
Portal hypertension, 170
Positioning, patient, 185, 230
Positive predictive value (PPV), 446
tumour markers, 302, 302
Positron emission tomography (PET),
61
POSSUM, 147
Posterior fossa intracranial haematoma,
36
Postoperative analgesia, 179, 351,
360-366
children, 366
day surgical patients, 366
elderly, 366
monitoring, 366-368
Postoperative assessment,
haematological, 105
Postoperative care, 349-356
after hospital discharge, 354
daycase surgery, 353-354
immediate (recovery phase), 349-350
on ward, 350-353
Postoperative complications, 354-356,
373-387
anastomotic leakage, 384
economic aspects, 443
haemorrhage, 386
490
INDEX
■
infective, 381-383
respiratory, 318, 354-355, 381
risk factors, 373-380
blood transfusion, 376-377
drug therapy, 375-376
type of pathology, 377-378
type of surgery, 378-380
surgical logbook, 464
venous thromboembolism, 380-381
wound problems, 385-386
Postoperative nausea and vomiting
(PONV), 368, 368
Postoperative pain, 351, 357-369
mechanisms, 357
non-pharmacological management,
359-360
pharmacological management see
Postoperative analgesia
reasons for treating, 359
Postphlebitic limb, 381
Postural hypotension, 5
Potassium (K + ), 108
effects of surgery, 318
in fluid regimens, 110, 111
postoperative replacement, 119, 352
requirements, 110
Potassium chloride (KC1), 74, 110, 111
Povidone-iodine, 210, 230
Power, study, 449-450
P-POSSUM, 147
Predictive value
negative (NPV), 424, 446
positive (PPV), 302, 302, 446
Prednisolone, 252
Pregnancy
causes of collapse, 14
drug prescribing, 134-135
uterine trauma, 26
Prejudices, 145
Preload, 389-390, 390
Premedication, 172-174
Preoperative assessment
anaesthetic, 172
cancer, 265-266
genetic disorders, 418-420
haematological, 90-93
risk assessment, 167, 168
Preoperative preparation, 165-171
antibiotic therapy, 166-167
high risk patients, 167-168
infection control aspects, 210
routine, 165-166
in specific patient groups, 168-171
thromboprophylaxis, 167
Presenting complaint, 50
Pressure sores, 244, 409
Prilocaine, 180, 181, 353
Primary survey, 3-8
Prions, 102, 201
Prisoners, 226
Probability, pre- and post-test, 447
Process, health care delivery, 430
Prochlorperazine, 173, 173
Procuren, 200
Professionalism, 226
Professional organizations, 440
Progesterone receptors (PR), 292
Progestins (progestogens), 292, 293
Prognosis, statistics, 450
Prognostic risk scores, 147
Programmed cell death see Apoptosis
Progressive disease (PD), 290
Prolonged operations, 379-380
Promethazine, 173, 173
Promoters, tumour, 263
Propacetamol, 360
Propofol, 174, 175
Propoxyphene, 179
Propranolol, 71, 170
Propylthiouracil, 71
Prostaglandins, 316, 317
Prostate cancer, 265, 279
non-surgical treatment, 292-293, 297
screening, 425
tumour markers, 306-307
Prostate-specific antigen (PSA), 306-307
Prostatic hypertrophy, benign (BPH),
306, 307
Prostatic surgery, 1 05
Prosthetic surgery, 203-204
see also Joint replacement surgery
Protamine, 105
Protein C, activated, 321
Protein-energy malnutrition (PEM),
125
Proteins
catabolism, in response to injury, 31,
319
osmotic effect, 107-108
pH changes and, 10
plasma, in fluid loss /excess, 113-114,
114, 115
Prothrombin complex concentrate,
100
Prothrombin time (PT), 76, 92, 103, 103,
165
Protocols, 57, 148,199
preoperative, 166
Proto-oncogene, 259, 263, 418
PRX-2 gene, 245
Pseudomembranous colitis, 208, 376
Pseudomonas aeruginosa, antibiotic-
resistant, 207
Psychiatric disease, 78, 159
Publication bias, 450-451
Pulmonary capillary wedge pressure
(PCWP), 112-113
Pulmonary embolism, 355, 380-381
prophylaxis see Thromboprophylaxis
Pulmonary metastases, 268, 298
Pulmonary oedema
dialysis, 400
hypotension with, 391
in smoke inhalational injury, 44
Pulse, 8
Pulseless electrical activity, 6, 14
Pulse oximetry, 350, 367-368
Pulse pressure, 9
Pupil size and responses, 8, 9
Pus swabs, 57
Pyrexia, postoperative, 355-356
Pyridostigmine, 17
Quality
clinical, 437-438
indicators, 439
monitoring, 439
Quality-adjusted life years (QALYs), 148,
443
Quality assurance committee, 432
Questioning, 459
Radiation
biological actions, 272-273
in cancer pathogenesis, 262, 262,
281-282
sources, 271-272
Radiation dose
distribution, linear accelerator, 271,
271-272
fractionation, 272
hyperfractionation, 275
late radiation complications and, 281,
281
radiological investigations, 60
tolerance of different tissues, 273
Radioactive isotopes, 271, 280
Radiographs, plain film (X-rays), 58,
59-60, 195-196
fluoroscopy, 60
intraoperative, 1 95-1 96
legal aspects, 196
operating theatre equipment,
196
preoperative, 195
safety, 60, 60, 196
Radiology see Imaging
Radiosensitivity, tumour, 273
Radiosurgery, stereotactic, 275
Radiotherapy, 271-283
accelerated, 275
adjuvant, 269, 277, 277-278
complications, 280-282
conformal, 274, 275
continuous hyperfrac donated
accelerated (CHART),
275
haemoglobin concentrations and,
97-98
immune effects, 87
new techniques, 275
palliative, 278-280
planning, 273-275, 274
postoperative, 278
preoperative, 278
to prevent graft rejection, 251
primary (curative), 276, 276-277
radiation sources, 272-273
role, 275-280
systemic disease, 280
treatment volume, 273-274
tumour size and, 272-273
Random allocation, 448
Randomized controlled trials (RCTs),
138
methods, 447-448
results, 448
sample size calculation, 449^450
491
INDEX
Raynaud's disease, 244
Reaming / intramedullary, 347
Reassurance, premature, 403
Recessive inheritance, 418
RECIST (response evaluation criteria in
solid tumours), 289-290
Records, 227
clinical diagnosis, 51-52
informed consent, 160
resuscitation, 16
review of clinical, 430
see also Logbook, surgical
Recovery
from anaesthesia, 178-179
phase, management, 349-350
Rectal trauma, 26
Red cell concentrates, 93, 96, 97-98
effects of storage, 97, 377
transfusion see Red cell transfusion
Red cell indices, in anaemia, 91-92
Red cells
antibodies, 96-97
inherited disorders, 92
Red cell transfusion, 97-98
indications, 97-98
massive, 98, 104
Re-epithelialization, 245, 323-324
Reflection coefficient, 108
Refusal of treatment, 159, 160, 161
Regional anaesthesia, 180-181, 182,
363-365
Rehabilitation, in chronic and terminal
illness, 403
Rejection, graft, 88, 250
acute, 250
chronic, 250
hyperacute, 250
prevention, 88, 250-252
Relative risk (RR), 448
Relative risk reduction (RRR), 448, 448
Relatives
bereavement, 413
breaking bad news, 461
communication with, 460
consent by, 158
end-of-life decisions, 388-389
intensive care patients, 396
organ donation, 249, 250
terminally ill patient, 299
Remifentanil, 178
Renal cell cancer, 294, 297
Renal disease, 75-76
cancer chemotherapy, 289
in diabetes, 375
drug prescribing, 135
kidney transplantation and, 253
Renal failure, 15, 398
acute, 41, 378, 394-395, 401
chronic, 75-76, 253
in diabetes, 73
dialysis, 400
Renal function
in elderly, 373
in obstructive jaundice, 378
Renal replacement therapy, 395
see also Dialysis
Renal system trauma, 26
Renin-angiotensin system, 32, 315
Research
consent to participation, 161-162
and development, 439
Respiration
accessory muscles, 394
effects of pain, 359
postoperative monitoring, 349,
367-368
Respiratory acidosis, 10, 10, 119
Respiratory alkalosis, 10, 10, 119
Respiratory complications,
postoperative, 318, 354-355,
381
Respiratory depression, 349, 364, 367,
408
Respiratory disease, 70-71
age-related risk, 373
heart and lung transplantation, 254
risks of surgery, 375
Respiratory distress, 394
Respiratory failure, 14
mechanical ventilation, 394
in myasthenia gravis, 78
in spinal injury, 38, 38
Respiratory rate, 4, 8, 367, 394
Respiratory support, 393-394
Respiratory system
inhalational injury, 4, 44
pathophysiology in critical illness,
391-394
response to surgery, 318
Respiratory tract infection, upper, 1 70
Resuscitation, 3-17
cardiopulmonary (CPR), 6-8
critically ill patients, 390-396
goals, 391
initial, and primary survey, 3-8
monitoring after, 8-13
secondary survey, 3, 13-16
withholding, 388-389
Retinoblastoma, 421
protein (Rb), 261
Retraction, skin edges, 243
Retroperitoneal haematoma, 26
Retroperitoneal trauma, 25-26
Revised Trauma Score (RTS), 45
Rhabdomyolysis, 13
Rheumatic heart disease, 67
Rheumatoid arthritis, 336-337, 379
Rib fractures, 21-22
Right bundle branch block, 69
Ringer's lactate see Hartmann's
solution
Risk
preoperative assessment, 167, 168
relative (RR), 448
Risk management, 147, 438
clinical, 147, 438
non-clinical, 438
organizational, 147
Risk reduction
absolute (ARR), 448
relative (RRR), 448, 448
Rituximab, 85
Road traffic accidents (RTA)
biomechanics of injury, 19, 19
prevention of injury, 18, 18
spinal injuries, 28
Rocuronium, 176, 178
Roentgen, W.K., 59
Rofecoxib, 361
Ropivacaine, 180, 181, 364
Royal Colleges, 440
Royal Colleges of Surgeons
intercollegiate examinations, 472-474
membership (MRCS) examination,
466-171
Rugby football, spinal trauma, 28
S-100, serum, 308
SAG-M blood, 97
Salicylate overdose, 15
Saline
hypertonic, 109, 111
normal, 109, 111, 117
Saliva, 115
Sample, 449
Sample size calculation, 449-450
Saphenous vein cutdown, 5
Sarcomas, 298
Sarin, 17
Scalds, 20, 243
Scalp injuries, 22-23
Scars
formation, 245, 324
hypertrophic, 234, 245, 329, 385-386
incisions near, 231
Scientific logic, 454-455
Scintigraphy, 61
Scoline apnoea, 175
Scoline rash, 175
Screening, 423-427
abuse, 426
bias, 423^24
cancer, 424— i26
compliance, 426
controversies, 427
costs, 427, 443
neonatal, 426
non-malignant disease, 426
population at risk, 424
radiological techniques, 62
test, requirements, 424
treatment of detected disease, 426
Scrubbing up, 200, 210
Scurvy, 328
Seat belt injuries, 26
Secondary survey, 3, 13-16
Sedation, 173, 174
daycase surgery, 354
monitoring, 367
opioid-induced, 408
Seizures, epileptic, 77
Seminomas, 299, 304
Semmelweiss, Ignaz, 206
Sensitivity
diagnostic test, 54-55, 446
screening test, 424
tumour markers, 302, 302
492
INDEX
■
Sentinel lymph node biopsy (SLNB),
267-268
Sepsis
acid-base balance, 123
drug therapy, 321
neutropenic, 290
postoperative, 383
see also Infections
Sepsis syndrome, 19
Septicaemia, postoperative, 383
Septic shock, 14, 19, 33, 390
postoperative, 383
Serotonin (5-hydroxytiyptamine, 5HT),
316
Severe combined immune deficiency
(SCID), 87
Sevoflurane, 176, 177
Sharp instruments (sharps)
disposal, 212, 218
injuries see Inoculation (needlestick)
injuries
precautions, 218, 219
Shaving, operation site, 166, 210, 230,
382
Shearing forces, 19
Shock, 14, 32-33, 390-391
anaphylactic, 14, 101, 390
assessment, 5
in burn injury, 42-43
cardiogenic, 14, 32, 390
causes, 32-33
distributive, 390
hypovolemic see Hypovolaemic
shock
neurogenic, 14, 32-33
obstructive, 390
preoperative management, 95
resuscitation, 5-6
septic see Septic shock
signs, 390
spinal, 39
Shoemaker's goals, 113, 168
SHOT (Serious Hazards of Transfusion),
96,101
Showering, preoperative, 210
Shunting, 391-392, 392, 393
Sickle cell crisis, 15
Sickle cell disease, 12, 75, 92, 344
Sidaway case, 157, 158
Signs, clinical, 51
Silicone
joint prostheses, 203
mammary prostheses, 204
tissue response, 204
Single gene disorders, 417
Single photon emission computed
tomography (SPECT), 61
Skeletal dysplasias, 419^120
Skin
characteristics, 241-242
cleansing (scrubbing up), 200
closure, 202, 234
cover, 241-248
functions, 241
healing see Wound healing
infections, surgical staff, 210
loss
closure, 246-247
mechanisms, 242-244
preparation, 184, 210, 230, 382
radiation side-effects, 280
substitutes, 247-248
tension (Langer's) lines, 231, 234,
242
trauma, 29, 242-243
wounds see Wound(s)
Skin grafts, 246-247, 249
donor sites, 235, 247
full thickness, 247
split thickness, 247
Skull fractures, 22-23, 36
Small bowel
immunity, 85
trauma, 25
Small cell lung cancer (SCLC), 296, 308
Small stomach syndrome, 411
Smoke inhalation, 4, 44
Smoking, 70-71, 171, 375
Sodium (Na + ), 108, 109
effects of surgery, 318
in fluid regimens, 111
loss, 114, 115
postoperative replacement, 119, 352
requirements, 110
retention, postoperative, 318
Sodium bicarbonate, 111, 123
hazards of therapy, 12, 123
in resuscitation, 11-12
Solvent abuse, 78
Somatic hypermutation, 83
Specialist Advisory Committees (SAC),
472, 473
Specificity
diagnostic test, 54-55, 446
screening test, 424
tumour markers, 302 302
Spillages, 212, 218
Spinal anaesthesia/analgesia, 180, 181,
365
Spinal cord, 28, 38
compression, in cancer, 279
Spinal cord injuries, 38-39
neurogenic shock, 32-33
partial, 38-39
primary damage, 38
secondary damage, 38
Spinal epidural haematoma, 1 67,
364-365
Spinal injuries, 28 , 37, 37-39
Spinal shock, 39
Spinothalamic tract, 38, 38-39
Spironolactone, 72
Splenectomy, 85, 1 70
Splenic trauma, 25
Sports, spinal trauma, 28
Spreadsheets, 463
Squamous cell carcinoma antigen (SCO,
308
Squashed stomach syndrome, 411
Stable disease (SD), 290
Stab wounds, 20, 22
Stainless steel implants, 203
Staphylococcus aureus
methicillin-resistant (MRSA), 54,
207-208, 375
vancomycin intermediate (VISA), 207
Staples, 201-202
Starling forces, 108
Starling's law, 389
Starvation, 314
Statistics, 445-453
comparative, 452, 456
critical appraisal, 456
diagnostic studies, 445-447, 446
prognostic studies, 450
systematic reviews /meta-analysis,
450-452
therapeutic studies, 447-450
Steam sterilization, 211
Steel's rule of three, 28
Stem cells, radiation damage, 280
Stents, 202
Stereotactic radiosurgery, 275
Sterilants, 211-212
Sterilization, 211-212
instruments, 201, 211
Sterispon, 202
Steri-strips, 234
Sternotomy, median, 233
Steroid hormones, wound healing and,
329
Steroid therapy see Corticosteroid
(steroid) therapy
Stoma appliances, 202
Stomach
cancer see Gastric cancer
trauma, 25
Stress response to surgery, 313-317, 359
in steroid-treated patients, 376
see also Surgery, body's response to
Stress ulcer, prophylaxis, 396
Stroke volume, 112, 113
Strong ion difference (SID), 122
Structure, health care delivery, 430
Sturge-Weber syndrome, 420
Subarachnoid haemorrhage (SAH), 15,
23,37
Subclavian vein, cannulation, 6
Subdural haematoma (SDH), 23, 37
Sugar, blood see Glucose, blood
Sulphonylureas, 73
Sulphur mustard, 17
Summative assessment, 467
Superior vena cava, obstruction (SVCO),
279
Supine hypotension, 14
Supraventricular tachycardia, 8
Surgeons
good practice, 225-229
logbook, 463-465
preparation for surgery, 210
risks of nosocomial virus
transmission, 215-222
Surgery, body's response to, 313-321
acute-phase response, 314, 316-317
clinically apparent systemic, 317-320
connective tissue and bone, 331-348
endocrine changes, 314, 315-316
493
INDEX
Surgery, body's response to (cont.)
initiation, 313-314
intracellular signalling processes, 317
manipulation, 313-321
in open vs laparoscopic surgery, 238
regulation, 314-317
sympathetic activation, 314-315
vascular endothelial response, 314, 317
Surgical access, 230-233
Surgical technique
infection prevention, 212, 381, 382
reducing exposure to blood, 219
Surgicel, 202
Surveillance of infections, 213
Survival curves, 450
Sutures, 201-202, 232
abdominal closure, 232-233
removal, 234
Suxamethonium, 175, 176, 177
Swabs, 202
precautions against loss, 233-234
pus, 57
Swan-Ganz catheter, 112-113
Sweat, replacing losses, 115, 115
SWOT analysis, 147
Sympathetic nervous system, 30, 32,
314-315
Symptom control, 404-412
Symptoms, 50
Synarthroses, 337
Syndrome, 418
Synovial fluid, 336
Synovial joints, 338
lubrication, 337-338, 339
Synovial membrane, 335-337
Syringe drivers, in terminal illness, 412,
412
Systematic reviews, 139, 450-452, 451
Systemic inflammatory response
syndrome (SIRS), 33, 320
Tabun, 17
Tachycardia, 318, 352
Tachypnoea, 32, 394
Tacrolimus, 87, 88
Tamoxifen, 292, 295, 296, 297
Tamponade, cardiac, 22
Tape closure, 234
Taxanes, 287
T cell receptors (TCR), 85, 86
T cells, 85-87
antigen recognition, 85-86
cytotoxic (CD8), 85, 86
deficiency, 86-87
function, 86
selection, 86
Teaching, 226, 228
Team membership, 227-228
Technetium-99m ( 99m Tc), 61
Temazepam, 173
Temperature
body see Body temperature
correction, blood gases, 121
operating theatre, 184
Tendons, 333-334
Tendon sheath, 334
Tensile strength, wounds, 324
Tension forces, 19
Tentorial herniation, 23, 35
Teratomas, 299
Terminal illness, 402^14
breaking bad news, 460-462
communication, 299, 403
definition, 402
emotional reactions, 403-404
symptom control, 404-412
terminal phase, 412-413
Terrorist attacks, chemical weapons, 1 7
Testicular trauma, 26
Testicular tumours, 299
adjuvant therapy, 269
spread, 267
tumour markers, 303-304
Tetracaine (amethocaine), 180, 181
Thalassaemia, 75, 92
Thalidomide, 134-135
T helper cells (CD4), 86, 86
Theory, 455
Therapeutic index, narrow, 136
Thermal injuries, 243-244
see also Burns
Thiazolidinediones, 73
Thiopental, 174, 174-175
Third space fluid losses, 318
Thoracic surgery, 1 70, 233, 379
Thoracic trauma, 21-22
Thoracoabdominal incision, 233
Thoracoscopy, 238
Thoracotomy, 233
emergency, 8
Three-dimensional preoperative
modelling, 63
Thrombin, 323
Thrombin time (TT), 92, 103
Thrombocytopenia, 75
heparin-induced (HIT), 93, 98
platelet transfusion, 98
Thrombocytopenic purpura
immune, 98
thrombotic, 98, 99
Thromboelastogram (TEG), 95, 103
Thrombophlebitis migrans, superficial,
378
Thromboprophylaxis, 167, 380
epidural analgesia and, 167, 365
in intensive care, 396
systematic reviews, 451, 451-452
Thromboxanes, 317
Thymectomy, 77-78, 87
Thymus, 85, 86, 86
agenesis, 86-87
Thyroid cancer, 280, 308
Thyroid disorders, 71
Thyroid surgery, 170
Thyrotoxicosis (hyperthyroidism), 71,
170
Thyroxine (T 4 ), 71, 316
Time management, 227
Tinel's sign, 40
TIPPS on the vowels mnemonic, 35
Tissue committee, 432
Tissue expansion, 247, 269
Tissue glues, 204-205, 205, 234
Tissue injury, in surgery, 313
Tissue perfusion, signs of inadequate,
390
Tissue planes, 231
Tissue transfer, 249, 249, 269
see also Transplantation
Tissue typing, 250-251
TNM staging system, 266
Tomography, 61
Topical analgesia, 180, 181
Topoisomerases, 285, 286
Total body irradiation, 280
Total body water (TBW), 107, 108
Total intravenous anaesthesia (TIVA),
177
Tourniquets, 185, 342, 379
Toxic epidermal necrolysis (TEN), 242
Toxic shock syndrome, 43^44, 243
Tracheal tube, drug administration via, 6
Training, 228, 439
minimal access surgery, 239-240
see also Intercollegiate specialty
examinations; MRCS
examination
Tramadol, 179, 362-363, 407
Tranexamic acid, 105
Transcellular water, 107, 108
Transcoelomic spread, cancer, 268
Transcutaneous electrical nerve
stimulation (TENS), 358, 359
TransCyte, 200
Transferrin, 125
Transfers, patient, 185
Transforming growth factor a (TGFa),
323, 326
Transforming growth factor p (TGFp),
245, 260-261, 323, 325, 326
Transmissible spongiform
encephalopathy (TSE), 211
Transplantation, 249-255
ethical issues, 254-255
historical development, 249
immunity, 87-88, 249
non-transplant surgery after, 79
specific organs, 252-254
tissue typing, 250-251
see also Organ donors; Rejection, graft
Transportation, resuscitated patients, 16
Trastuzumab (Herceptin), 291, 294,
294-295
Trauma, 18-46, 331-332
abdomen, 25-26
airway, 22
anatomical sites, 21-29
biomechanics of injury, 19-21
blast injuries, 21
blunt, 19-20
bony pelvis, 27
burns see Burns
circulation, 22
connective tissue and bone responses,
331-348
energy transfer, 20
genitourinary system, 25-26
494
INDEX
head see Head injury
limbs, 27-28
maxillofacial skeleton, 23-25
metabolic response, 29-32
pathophysiological response, 29, 29-45
penetrating, 20
severity scoring, 45
skin, 29, 242-243
skull, 22-23
spinal column see Spinal injuries
surgical, 313,332
response to see Surgery, body's
response to
thorax, 21-22
trimodal mortality pattern, 18-19
Treatment
futile, 160-161
life-saving, 158, 160
refusal, 159, 160, 161
statistical analysis, 447-450
withholding, 388-389
Tremor, in microscopic surgery, 197
Tricyclic antidepressants, 15, 78
Tri-iodothyronine (T 3 ), 316
TRISS, 45
Troglitazone, 73
Trophoblastic tumours, 299, 303
Trust, patient, 226
D-Tubocurarine, 177
Tumour(s)
antigens, 88
growth, 284
malignant see Cancer
metastasis, 261, 261-262
promoters, 263
radiosensitivity, 273
spread, 266-268
Tumour markers, 266, 302-309
clinical applications, 302-303
definitions, 302, 302
in specific tumours, 303-308
Tumour necrosis factor a (TNFa), 30, 33,
316, 326-327
Tumour suppressor genes, 259, 260, 418,
420
Type I error, 449
Type II error, 449
Tyrosinase, 308
Tyrosine phosphorylation, 259
Ulceration, 244, 329
Ultrafiltration, 400, 400
Ultrasonic harmonic scalpel, 194-195
Ultrasonic surgical aspirator (CUSA),
194
Ultrasound imaging, 60, 194-195
in deep vein thrombosis, 380
endoscopic (EUS), 60
interventional, 62
intracavitary, 60
intraoperative, 62, 194
laparoscopic, 239
Unconscious patients
consent issues, 158, 161
see also Coma; Consciousness
Universal precautions, 218
Uraemia, 400
Urea, urinary, 128
Ureteric injury, 26
Urethral trauma, 26
Urinary catheterization, 8
Urinary output, 9, 395
Urinary system trauma, 26
Urogastrone, 326
Urological tumours, 297
Urology, 189, 350
Uterine trauma, 26
Utility 148, 149
expected, 148, 149
Valvular heart disease, 67-68, 374
Vancomycin intermediate Staphylococcus
aureus (VISA), 207
Vascular damage, radiation, 281
Vascular endothelial growth factor
(VEGF), 244, 245, 262
Vascular supply, wound healing and,
231, 329
Vascular surgery
implant materials, 203
interventional radiology, 62
laser therapy, 189
postoperative care, 350
preoperative preparation, 170-171
Vascular trauma, 26, 27-28
Vasoactive drugs, 391
Vasopressin see Antidiuretic hormone
Vecuronium, 178
Veins, trauma, 28
Venography, 380
Venous access
long term, 289
for resuscitation, 5
Venous cutdown, 5
Venous drainage, wound healing and,
329
Venous thromboembolism, 380-381
in cancer, 378
complications, 380-381
diagnosis, 380
incidence, 380
inherited causes, 419
in orthopaedic surgery, 379
prophylaxis see Thromboprophylaxis
risk factors, 167, 380
treatment, 380
Ventilation
dead space, 392, 392
mechanical see Assisted ventilation
Ventilation-perfusion (V/Q) matching,
391-392, 392
Ventilation systems, theatre, 183-184,
199, 209
positive pressure (plenum), 209
ultraclean, 209
Ventilatory failure see Respiratory
failure
Ventricular fibrillation, 6-7, 14
Ventricular septal defect, 67
Venturi masks, 393
Vertebral column, Steel's rule of three,
28
Vertebral fractures
Chance, 19
traumatic, 28
Vinca alkaloids, 287
toxicity, 290, 291
Virchow, Rudolf, 324
Viruses
blood-borne, 215-222
infected healthcare workers,
220-221
reducing infection risk, 218-220
risks to healthcare workers, 217
sources of infection, 217
nosocomial infections, 215
oncogenic, 262, 262-263
surgical staff infections, 210
in T cell deficiency, 86-87
in tissue glues, 205
transfusion-related transmission, 99,
102, 102
Viscera, response to surgery, 315
Visceral pain, 405
Vitamin A, 328
Vitamin C, 328
Vitamin D, 398, 401
Vitamin K, 93, 99, 105, 169, 386
Vitronectin, 323
Viva voce, MRCS examination, 467, 468,
469-470
Volkmann's contracture, 333
Vomiting see Nausea and vomiting
Von Hippel-Lindau syndrome, 421
Von Willebrand's disease, 99
Walking see Gait
Wallerian degeneration, 40
Ward round, postoperative, 351
Warfarin
preoperative therapy, 90, 93, 165
reversal, 99
thromboprophylaxis, 380
in venous thromboembolism, 380
Waste disposal, 212
Water
deprivation test, 72
requirements, 109-110, 110
total body (TBW), 107, 108
see also Fluid
Weak acids, 122
Weakness, in terminal illness, 409
Weight reduction, before surgery, 374
Wenckebach phenomenon (Mobitz type
1 heart block), 69
Wernicke's encephalopathy, 13
Whiplash phenomenon, 28
White cell count (WCC), raised, 57
Wide local excision, breast cancer, 267
Will Rogers' effect, 456
Wilms' tumour, 421
Wolff's law, 344
World Health Organization (WHO)
analgesic ladder, 1 79
clinical quality, 437
495
INDEX
Wound(s), 241
assessment 242
chronic, 200
classification, 381-382
clean (class I), 166, 166, 206
clean-contaminated (class II), 166, 206
closure see Closure
complications, 385-386
contaminated (class III), 166, 167, 206
contraction, 245, 325
contracture, 42, 245
debridement, 245-246
dehiscence, 232-233, 385
dirty (class IV), 206
dressings, 200, 234-235
exuding, 200, 235
haematoma, 386
incised, 322-324
malignant transformation, 241
open, 200, 235
principles of management, 235
retraction of skin edges, 243
skin cover, 241-248
tensile strength, 324
Wound healing, 42, 320, 322-330
biology, 244-245
in bone, 39, 327-328
in cancer, 378
complications, 329
corticosteroid therapy and, 376
in diabetes, 242, 245, 329, 375
factors affecting, 328-329, 385
fundamental requirements, 322
nervous tissue, 328
in obstructive jaundice, 377
by primary intention, 246, 322-324
problems, 385-386
by secondary intention, 246, 322,
324-327
skin substitutes, 247-248
superficial disruption, 385
vascular supply and, 23 1
Wound infections
classification of risk, 166, 206
dressings, 200
in orthopaedic surgery, 379
prevention, 206-214, 382-383
risk factors, 381-382
surveillance and audit, 213
treatment, 383
Xenografts, 249, 250
Xenon, 176, 177
X-rays
diagnostic see Radiographs, plain
film
radiotherapy, 271-272
Yellow Card Scheme, 133
Zidovudine (AZT), 220
Zinc, 328-329
Zygomatic complex fractures, 24
496
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The New Aird's
COMPANION
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CLINICAL
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Manoj Ramachandran
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