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Fundamentals of Surgical Practice

This is the new, expanded and updated edition of the keytext currently available for the first stages of the MRCSexamination. Mirroring the exam syllabus, it offers thetrainee a clear understanding of the core knowledgerequired for examination success and incorporates newmaterial reflecting recent developments and the new examination. The chapters have been written by acknowledged experts, many of whom are themselvesinvolved in the training and examining of candidates.Designed to achieve maximum efficiency in learning, thecontent provides ample detail, key points and suggestionsfor further reading. In addition to a detailed index, eachchapter has its own table of contents to enhance ease ofuse. It will be indispensable for the new trainee, and willalso provide established surgeons and other healthcare professionals working in the surgical environment with amodern, authoritative overview of the key areas of surgicalpractice.

Prof. Andrew N Kingsnorth is a Consultant Surgeon atDerriford Hospital in Plymouth and Professor of Surgery atPeninsula Medical School, University of Plymouth. He iscurrently an associate editor of the International Journal ofSurgical Investigation and has been an editorial boardmember for the British Journal of Surgery (1996–1999). Prof. Kingsnorth also spent many years as a Member of theCourt of Examiners of the Royal College of Surgeons ofEngland (1994–2000) and has published over 300 articlesand invited chapters in 30 books, as well as co-editing 6books and co-authoring 1 book.

Aljafri A Majid is a Consultant Cardiothoracic Surgeon atUniversity Hospital, Kuala Lumpur and Professor in theDepartment of Surgery at the Faculty of Medicine,University of Malaya. He is also a member of the Panel ofExaminers for the Royal College of Surgeons of Edinburgh.

Fundamentals of Surgical PracticeSecond Edition

Edited by

Andrew N Kingsnorth and Aljafri A Majid

CAMBRIDGE UNIVERSITY PRESS

Cambridge, New York, Melbourne, Madrid, Cape Town, Singapore, São Paulo

Cambridge University PressThe Edinburgh Building, Cambridge CB2 8RU, UK

First published in print format

ISBN-13 978-0-521-67706-6

ISBN-13 978-0-511-34939-3

© Cambridge University Press 2006

Every effort has been made in preparing this publication to provide accurate and up-to-date information which is in accord with accepted standards and practice at the time of publication. Although case histories are drawn from actual cases, every effort has been made to disguise the identities of the individuals involved. Nevertheless, the authors, editors and publishers can make no warranties that the information contained herein is totally free from error, not least because clinical standards are constantly changing throughresearch and regulation. The authors, editors and publishers therefore disclaim all liability for direct or consequential damages resulting from the use of material contained in this publication. Readers are strongly advised to pay careful attention to information providedby the manufacturer of any drugs or equipment that they plan to use.

2006

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Preface viiContributors viii

Contents

1 Preoperative management 1F Rosewarne & B Thomson

2 Principles of anaesthesia 16CMH Gómez & JWW Gothard

3 Postoperative management 39DM Bowley

4 Nutritional support 50J Payne-James

5 Surgical sepsis: preventionand therapy 58QM Nunes, CV Soong & BJ Rowlands

6 Surgical techniques and technology 71RM Kirk

7 Trauma: general principles of management 89C Macutkiewicz & ID Anderson

8 Intensive care 111A Neville & AA Majid

9 Principles of cancer management 149AP Forrest & MS Duxbury

10 Ethics, legal aspects and assessment of effectiveness 184SJ Leinster

11 Haemopoietic and lymphoreticular systems: anatomy, physiology andpathology 199DC Strauss, AJ Botha & I Taylor

12 Upper gastrointestinal surgery 230TJ Wheatley

13 Lower gastrointestinal surgery 249DM Bowley & C Cunningham

14 Hernia management 264AN Kingsnorth

15 Vascular surgery 286JR Barwell & ZH Khan

16 Endocrine surgery 304D Lee & RG Hardy

17 The breast 322SD Heys

18 Thoracic surgery 351CP Clarke

19 Genitourinary system 369N Harris & A Dickinson

20 Head and neck 391WWK King, JKS Woo & DSC Lam

21 The central nervous system 415J Palmer

22 Musculoskeletal system 440SP Frostick & V Sahni

23 Paediatric surgery 493PKH Tam

Index 525

Preface

One of the first challenges for aspiring surgeons to negotiateis the intercollegiate MRCS examination, which has replacedsimilar examinations previously run by the four RoyalSurgical Colleges. The first edition of Fundamentals ofSurgical Practice has become a recommended and standardtext for the MRCS examination largely due to the reputationof its contributors. As editors of the second edition we aredelighted that the majority of our authors have signed up toa revision and update of their chapters. There are some newcontributors and some of our senior authors have revisedtheir chapters with junior colleagues attuned to modern sur-gical thinking.

Technological aspects of surgery have undergone rapidchange in the last two decades. A parallel change has takenplace in the educational concepts underpinning transfer ofbasic knowledge into surgical practice. The knowledge baseitself may not have changed a great deal but its method of

presentation has. Therefore, we have selected authors with agift for imparting the enthusiasm of their specialist interestin a straightforward and easily understood way but withoutmissing out on the detail. In this edition the alimentary sys-tem has been expanded into two chapters on Upper gas-trointestinal and Lower gastrointestinal surgery and aseparate chapter on Hernia management has been added toemphasise the importance of surgery of the abdominal wallas an expanding area of specialist interest. The successfulformat of the previous edition has been retained and we areconfident that this book will continue to remain a popularreference source for those beginning their postgraduatetraining in surgery.

Andrew N KingsnorthAljafri A MajidFebruary 2005

Iain D AndersonBSc MD FRCS FRCS(Gen)Consultant SurgeonHope Hospital, ManchesterSenior Lecturer in Surgery, University of ManchesterHillsborough Tutor in Critical Care, The Royal College ofSurgeons of England, Manchester, England

JR BarwellConsultant Vascular and Renal Transplant Surgeon,Derriford Hospital, Plymouth, UK

Abraham J BothaMD FRCSDepartment of Upper GI and General SurgerySt Thomas’ Hospital, London, UK

Douglas M BowleyDepartment of Colorectal Surgery, John Radcliffe HospitalHeadley Way, Headington, Oxford, UK

C Peter ClarkeMBBS(Melb) FRACS FACS FCCPSenior Thoracic SurgeonAustin and Repatriation Medical Centre, Heidelberg,Victoria, AustraliaProfessorial Associate, Department of Surgery, University ofMelbourne, Victoria, Australia

Christopher CunninghamDepartment of Colorectal Surgery, John Radcliffe HospitalHeadley Way, Headington, Oxford, UK

Andrew DickinsonMD FRCS (Urol)Derriford Hospital, Plymouth, UK

Mark S Duxbury

Oleg EreminMD FRCS(Ed) FRACSHonorary Consultant SurgeonAberdeen Royal Hospitals NHS Trust, AberdeenRegius Professor of Surgery, University of Aberdeen, AberdeenExaminer in Surgery, Royal College of Surgeons, Edinburgh, UK

Mark FordhamFRCSConsultant UrologistRoyal Liverpool University HospitalMember, Court of Examiners, Royal College of Surgeons,England

A Patrick ForrestFRCS(Ed, Eng, Glasg) MD ChM HonDSc (Wales, ChineseUniversity of Hong Kong) LLD (Dundee) HonFACS FRACSFRCS(Can.) FRCRProfessor Emeritus, University of EdinburghSenior Lecturer in Surgery, University of GlasgowProfessor of Surgery, Welsh National School of MedicineRegius Professor of Clinical Surgery,University of Edinburgh, Member of Council, Royal Collegeof Surgeons, Edinburgh, UK

Simon P FrostickMA DM FRCSHonorary ConsultantRoyal Liverpool University HospitalProfessor of Orthopaedics, University of Liverpool,Liverpool, UK

Carlos MH GomezLMS FRCAHonorary Senior Registrar and Research FellowDepartment of Anaesthesia and Intensive Care, CharingCross Hospital, London, UK

John WW GothardMBBS Dip(Obst) RCOG FRCAConsultant Anaesthetist, Royal Brompton HospitalHonorary Senior Lecturer, National Heart and LungInstitute, Imperial College School of Medicine, London, UK

Roshan Lall GuptaMS FRCS(Eng) FRCS(Ed) FACSEmeritus Professor of SurgeryMeerut, India

Contributors

Robert G HardyBSc MB ChB PhDDepartment of Endocrinology, Royal Infirmary,Edinburgh, UK

DR HarperBSc MD FRCSConsultant SurgeonFalkirk and District Royal Infirmary NHS TrustHonorary Senior Lecturer, Department of Surgery,University of EdinburghExaminer, Royal College of Surgeons, Edinburgh and Royal College of Physicians and Surgeons,Glasgow, UK

Neil HarrisMD MRCS(Eng)Department of Urology,Derriford Hospital, Plymouth, UK

Steven D HeysMD PhD FRCS(Glas) FRCS(Ed)Honorary Consultant SurgeonAberdeen Royal Hospitals NHS Trust, AberdeenReader in Surgery, University of Aberdeen, AberdeenExaminer in Surgery, Royal College of Surgeons, Glasgow, UK

Jason Payne-James19 Speldhurst Road, London, E9 7EH, UK

RV JeffreysMChir FRCS(Ed)Consultant NeurosurgeonWalton Centre for Neurology and Neurosurgery, LiverpoolClinical Lecturer in Neurosurgery, University of Liverpool,Liverpool, UKExaminer, Royal College of Surgeons, EdinburghMember of Specialist Advisory Board in Neurosurgery,Royal College of Surgeons of EdinburghPreviously Examiner in Conjoint FRCS (Surgical Neurology),Edinburgh, UK

ZH KhanLocum Consultant Vascular Surgeon,Derriford Hospital, Plymouth, UK

Walter WK KingMD FRCS(Ed) FRCS FACS FCSHKChief, Division of Head and Neck – Plastic andReconstructive SurgeryPrince of Wales Hospital, Shatin, Hong KongProfessor of Head and Neck – Plastic and ReconstructiveSurgery, The Chinese University of Hong Kong, Hong Kong,China

Panel of Examiners (1992–1998), Conjoint FellowshipExamination of the Royal College of Surgeons of Edinburghand the College of Surgeons of Hong KongExaminer, Joint Inter Collegiate Higher SpecialistExamination, RCS Edinburgh/CSHK Conjoint Examination(1996–1998)

Andrew N KingsnorthBSc MS FRCSConsultant SurgeonDerriford Hospital, PlymouthHonorary Professor of Surgery, Peninsula Medical SchoolExternal Undergraduate Examiner, Oxford, London andKuala Lumpur, Malaysia Member, Court of Examiners, Royal College of Surgeons ofEngland, UK

RM KirkMS FRCSHonorary Consulting SurgeonRoyal Free Hospital, London, UK

Dennis SC LamMBBS DO FRCS FRCOphthDepartment of Ophthalmology and Visual SciencesPrince of Wales HospitalAssociate Professor, Department of Ophthalmology andVisual Sciences, The Chinese University of Hong Kong,Hong Kong, China

David LeeBSc MB ChB FRCS(Ed)Consultant General and Endocrine Surgeon, RoyalInfirmary, Edinburgh, UK

Sam J LeinsterBSc MD FRCSLead Clinician, Breast Cancer ServicesHonorary Consultant Surgeon, Royal Liverpool andBroadgreen HospitalsProfessor of Surgery and Director of Medical Studies,University of LiverpoolExaminer, Royal College of Surgeons, EdinburghExaminer, PLAB, General Medical CouncilMember, Training Committee and ExaminationsCommittee, Royal College of Surgeons, Edinburgh, UK

Roderick Anderson LittlePhD FRCPath FFAEMProfessor of Surgical ScienceUniversity of Manchester, ManchesterHead, MRC Trauma Group, Director NWIRC, Member,Court of Examiners, Royal College of Surgeons, London, UK

C MacutkiewiczDepartment of Surgery, Hope Hospital, University of Manchester, School of Medicine

ix Contributors

Aljafri A MajidMBBS BmedSc(Hons) FRCS(Ed) FRCSEd(CT)Consultant Cardiothoracic SurgeonUniversity Hospital, Kuala Lumpur, MalaysiaProfessor and Head, Department of Surgery, Faculty ofMedicine, University of Malaya, MalaysiaMember, Panel of Examiners, Royal College of Surgeons,Edinburgh, UK

Angela NevilleDepartment of Surgery, University of Southern California,Los Angeles, USA

QM NunesClinical Fellow in General Surgery, Queen’s Medical Centre,Nottingham, UK

Fred RosewarneMBBS FANZLAAssistant DirectorDepartment of Anaesthesia, Royal Melbourne HospitalClinical Instructor, Royal Melbourne and Western HospitalClinical SchoolSupervisor of Training in Anaesthesia, Royal MelbourneHospital, Melbourne, Australia

Brian J RowlandsMD FRCS FACSConsultant SurgeonQueen’s Medical Centre, University of Nottingham,Nottingham, UKProfessor of Surgery; Chairman of RCS England WorkingParty on Care of the Critically Ill Surgical Patient

RC SmithMB ChB ChM FRCS(Ed)Consultant SurgeonFalkirk and District Royal Infirmary NHS TrustHonorary Clinical Teacher, University of EdinburghConvenor of The Examinations Committee, Royal College ofSurgeons of Edinburgh, Edinburgh, UK

Chee Voon SoongMB BCH FRCSISpecialist Registrar in General and Vascular SurgeryRoyal Victoria Hospital, Queen’s University of Belfast, BelfastNorthern Ireland Postgraduate Surgical TrainingProgramme, UK

Dirk C StraussMBChB, FCS(SA), MMed(Stell)Department of Upper GI Surgery, St Thomas’ Hospital,London, UK

Paul KH TamMBBS(HK) ChM(Liverpool) FRCS(Edin, Glas, Ire) FRCPCHFHKAM(Surgery) FCSHKChief, Division of Paediatric SurgeryDepartment of Surgery, Queen Mary HospitalChair of Paediatric Surgery, Department of Surgery, TheUniversity of Hong Kong Medical CentreQuandom Fellow, Lincoln College, University of Oxford.(Formerly, Clinical Reader, Director and Consultant (Hon.)in Paediatric Surgery, University of Oxford and JohnRadcliffe Hospital, Oxford 1990–1996)Examiner in Fellowship (General Surgery), Royal College ofSurgeons, EdinburghExaminer, Intercollegiate Specialty Board in PaediatricSurgery (UK)Examiner in Diploma of Child Health, Royal College ofPhysicians (UK)Examiner in Fellowship (General Surgery), College ofSurgeons of Hong Kong, Hong Kong, China

Irving TaylorMD ChM FRCSConsultant SurgeonUniversity College London Hospitals NHS Trust, LondonProfessor of Surgery and Head of Department of SurgeryUniversity College London, London, UK

Robert JS ThomasMBBS MS FRACS FRCSWestern Hospital, Victoria, AustraliaDepartment of Surgery, University of Melbourne, Victoria,Australia

Benjamin ThomsonDepartment of Surgical Oncology, Peter MacCallum Cancer Centre

TJ WheatleyConsultant Upper GI Surgeon, Derriford Hospital,Plymouth, UK

John WooFRCSEd FHKAM (otorhinolaryngology)ConsultantDepartment of Surgery, Prince of Wales Hospital, ChineseUniversity of Hong KongAdjunct Associate Professor, Chinese University of HongKong, Hong Kong, China

Contributors x

PREOPERATIVE A SSESSMENT

Introduction

The preoperative evaluation of patients is intended to reducethe morbidity and mortality associated with surgery andanaesthesia. The relative benefits of the proposed operationneed to be balanced against the possible adverse effects thatmay result from anaesthesia and surgery. The severity of anyunderlying medical conditions and their impact on physio-logical reserve must be assessed. Optimisation of the manage-ment of any underlying medical condition is undertaken. It isnecessary to take a detailed history, examine the patient andobtain appropriate laboratory investigations to achieve these

goals. A plan for anaesthesia, postoperative care and painrelief can then be constructed and this generally involves:• informing patient of the proposed procedure;• obtaining informed consent for proposed procedure,

including any risks from not having the procedure;• assessing pre-existing conditions and estimation of their

impact on physiological reserve;• planning the type of anaesthesia guided by the above infor-

mation and patient preferences;• planning postoperative management of any pre-existing

conditions;• planning analgesia.The American Society of Anesthesiologists’ (ASA) classifica-tion has found wide acceptance as a broad-based system forclassifying the general fitness of patients for surgery and theirpredicted mortality (Table 1.1).

Factors increasing the operative risk include:• age �70 years;• surgery �3 h duration;• emergency versus elective operation;• presence of associated illnesses (especially uncontrolled

diabetes or heart failure);• physiological reserve impaired;• obesity, malnutrition, immunosuppression and cancer;• radiotherapy, steroid use.

1

Preoperative ManagementFred Rosewarne1 and Benjamin Thomson21Department of Anaesthesia, Royal Melbourne Hospital and Western Hospital Clinical School, Melbourne, Victoria, Australia 2Department of Surgical Oncology, Peter MacCallum Cancer Centre

CONTENTS

Preoperative assessment 1Introduction 1General preparation 2

Preoperative assessment of fitness foranaesthesia and surgery 3Cardiovascular system 3Respiratory system 5Central nervous system 6Renal system 7Liver 7Endocrine system 8Haematology 9

Lifestyle influences on anaesthetic risk 10

Concurrent drug treatment 11

Prophylaxis of thromboembolic disease 13

Preadmission clinics 14

Routine investigations prior to surgery 14

Further reading 15

Table 1.1. ASA classification of illness.

1 No organic, physiological, biochemical or psychiatric

disturbance

2 Mild to moderate systemic disturbance which does not limit

normal activities

3 Severe systemic disturbance which limits normal activities

but is not incapacitating

4 Severe, life-threatening systemic disorders

5 Moribund with little chance of survival

6 Increasingly ASA 6, is used to designate an organ donor

E ‘E’ placed after the number, indicates an emergency

operation

General preparation

ConsentConsent is a very important process in the preoperative man-agement of patients. It is much more than informing thepatient of the risks of the procedure and should include dis-cussion of:• An explanation of the condition requiring surgery and why

that surgical procedure is considered the best option.• Other treatments that could be considered as well as the

expected outcome without treatment.• A description of what will be done at the time of the

procedure (i.e. what will be removed, site of incision andreconstruction).

• The expected anaesthetic management (i.e. general anaes-thesia versus regional anaesthesia and sedation).

• What to expect following the anaesthetic (i.e. drain tubes,central venous and urinary catheters, stomas, etc.).

• Expected long-term outcomes and implications of theprocedure.

• Confirmation of the side and site of the procedure to avoid‘wrong site or side’ procedures.

To aid patient education and consent many surgical collegesand societies produce patient information pamphlets for com-mon procedures.

Discussion of the complications of surgery can be anexhaustive process if all possible problems are discussed. Somepatients may require a further consultation for follow-up dis-cussion. Many patients will require the presence of a profes-sional interpreter for the consent process, with family used fortranslation only when an interpreter is not available. Eachpatient needs to be individually assessed as some complica-tions may be of greater significance than for other patients,even if very uncommon or rare. The discussion of risk for a pro-cedure should be based on a balance of the benefit of the oper-ation against its complications. In this component of theconsent there should be discussion of:• Common risks of any procedure and plans to avoid them

(i.e. the use of heparin to avoid deep venous thrombosis,the importance of postoperative mobilisation in prevent-ing deep venous thrombosis and pulmonary atelectasis);

• Specific risks of the procedure;• Anaesthetic consent.The legal interpretation of the consent process often differsto the medical interpretation. The laws regarding the con-sent process differ in each country. Furthermore, the age apatient is able to give informed consent differs according tothe country and social circumstances. Health care providersmust acquaint themselves with the particular legal and con-sent protocols in their locality and health care facility. Somespecific situations should be considered in detail:• Emergency: When urgency or the patient’s clinical state pre-

cludes the obtaining of a valid consent, life-saving treatmentmay commence. This decision must be documented.

• Under-age patients: Parents can consent for their childrenhowever the legal situation becomes increasingly complex

for adolescents over 16 years, with considerable variationbetween countries and states/provinces. The clinicianshould be aware of the local practice.

• Incompetent patients: Consent should be obtained fromthe legally appointed guardian or the ‘Person Responsible’as defined by the local Guardianship Board or equivalent.

• Religious and cultural issues: Restricted consent can begiven by patients to allow certain treatments but not forothers. A common example is Jehovah’s Witnesses whomay consent to surgery but not allow blood transfusion.The issues involved with the use of cell-savers and extra-corporeal bypass and specific blood products needs to bediscussed in detail with Jehovah’s Witnesses because thereis some variation in attitudes to ensure there is no misun-derstanding. In emergency situations where the patient’swishes are not clearly known, the patient must be treatedaccording to Standard Protocols. In the case of childrenunder 16 where blood transfusion is deemed necessary,application to the appropriate authority will be required ifparental consent for transfusion is withheld.

EmergenciesIn the emergency situation, estimation of physical status iscompromised by the need to manage the presenting illness. Ahistory may need to be taken from relatives during preopera-tive resuscitation and thorough physical examination may bedifficult. Hospital records, if available, are invaluable to excludesystemic illness. Accurate estimation of fluid status is an essen-tial part of successful preoperative management. Knowledge of the time course of the illness is important in guiding thisprocess since previous fluid losses are particularly difficult toassess. Ongoing losses must be documented, bearing in mindthat concealed losses are notoriously difficult to estimate.Serum electrolyte concentrations may significantly underesti-mate fluid losses in the presence of isotonic losses. Correctionof problems such as fluid deficit and electrolyte imbalance canproceed while the patient is being prepared for emergency sur-gery. Preoperative resuscitation can nearly always be per-formed prior to surgery except in cases of life-threateninghaemorrhage.

AgeIncreasing age increases perioperative risk because of pro-gressive reduction in functional reserve of organ systems as

2 Fundamentals of surgical practice

Table 1.2. Effect of age on physiological processes.

% decline from

Function 20–30 to 60–80 years

Cardiac output 20

Muscle mass 20

Maximal breathing capacity 60

Cortical neurones 50

Hepatic blood flow 25–40

well as increasing illnesses associated with increasing age.The commonest co-morbidities are arthritis, hypertension,diabetes and cardiac disease (Table 1.2).

PREOPERATIVE A SSESSMENT OF F ITNESSFOR ANAESTHESIA AND SURGERY

Cardiovascular system

Cardiac risk factorsNumerous studies have attempted to define the aetiologicalfactors associated with perioperative cardiac complicationsand several risk assessment indices have been published.Patients may be classified as low risk (�3%), intermediate(3–10%) or high risk (�10%) of major adverse cardiac events.

Major risk factors are:• myocardial infarction within previous 3 (major risk) or

6 (moderate risk) months;• unstable angina;• untreated cardiac failure;• significant aortic valve stenosis;• untreated hypertension.

Relative risk factors are:• prior myocardial infarction;• jugular vein distension (or S3 gallop);• non-sinus rhythm;• ventricular ectopic beats/min;• age �70 years;• surgery �3 h duration;• emergency surgery;• significant medical impairment: PaO2 � 60 mmHg,

PaCO2 � 50 mmHg and K � 3 mmol/l;• chronic liver impairment.Postoperative cardiac complications result from patients withimpaired physiological reserve being unable to cope with thestresses of the perioperative period. Factors impinging on thephysiological reserve include:• myocardial depression from sepsis and anaesthetic agents;• variable pre- and after-load due to fluid shifts associated

with disease, surgery and fluid replacement regimens;• reduction in oxygen transport secondary to myocardial

depression, intrapulmonary shunting, blood loss and pain-or drug-induced hypoventilation;

• miscellaneous factors such as hypotension, acidosis, tachy-cardia, fluctuating blood levels of therapeutic agents.

Ischaemic heart diseaseRecent consensus guidelines from the USA (American HeartAssociation and American College of Physicians) plus researchin Europe has produced algorithms to assist evaluation of at-risk patients prior to non-cardiac surgery (American Collegeof Physicians, 1997; Chassot et al., 2002).

Myocardial infarctionThe risk of perioperative myocardial infarction is most stronglycorrelated with previous infarction history (Table 1.3) or the

presence of inadequately treated cardiac failure. The mortal-ity rate from perioperative myocardial infarction is high(40–60%). Previously 6 months was considered the minimumtime between uncomplicated myocardial infarction and elect-ive surgery, but recent data supports a 3-month minimumperiod. In the event that surgery cannot be delayed, a fullassessment of cardiac function is required and intraoperativemonitoring using transoesophageal echo (TOE) or Swan–Ganzcatheter may be desirable. Postoperatively, the patient shouldbe cared for on an intensive care unit for the first 24 h becausethe risk of reinfarction continues in the postoperative period(15% in the first 48 h). In the elective patient, evidence of signif-icant ischaemic changes on stress testing may be followed bycoronary angiography and possible percutaneous coronarystents or coronary bypass grafting prior to elective surgery.Prophylactic perioperative beta-blockade has been shown toreduce risk in patients with proven coronary artery disease,although specific protocols are uncommon in clinical practice.A titration of heart rate to �65 bpm has been widely supported.

AnginaThe clinical assessment of the severity of angina may be basedon the grading system devised by the New York HeartAssociation (Table 1.4). Patients in classes 1 and 2 undergoinglow or intermediate risk surgery are at no increased risk withsurgery but should have exercise electrocardiograms (ECGs)prior to surgery. Anti-anginal medication should be continuedthrough the preoperative period. Patients in classes 3 and 4,especially those scheduled for intermediate- or high-risk non-cardiac surgery should be considered for coronaryangiography and possible revascularisation or coronary stentpercutaneous trans luminal coronary angioplasty (PTCA) priorto elective surgery. This is because of the high incidence ofmyocardial infarction when elective surgery is performed onthis group, however to date, no randomised controlled clinicaltrial has assessed the overall benefit of prophylactic coronarygrafting to lower cardiac risk during non-cardiac surgery.

Preoperative management 3

Table 1.3. Risk of myocardial infarction.

• No previous infarction 0–5%• Acute myocardial infarction �6 months previously 6%• Myocardial infarction 3–6 months ago 10%• Infarction �3 months ago 30%

Table 1.4. Risk of myocardial infarction.

Class 1 Angina with strenuous exercise

Class 2 Angina with moderate exercise

Class 3 Angina after climbing 1 flight of stairs or walking 1 block

Class 4 Angina at rest

Investigation• Chest Radiograph: A relatively non-specific test although

cardiomegaly and venous congestion associated with car-diac failure can be detected.

• ECG: A normal resting ECG does not exclude the presenceof ischaemic heart disease. Ambulatory ECG during the48 h prior to surgery in patients with known coronary arterydisease has shown silent ischaemic episodes in 18–40% ofpatients. However, in the absence of symptoms and signs ofcoronary disease, there is good correlation between a nor-mal resting ECG and an uneventful preoperative course.

• Stress ECGs: A significant correlation with the developmentof preoperative complications is shown in patients who:– show ischaemic changes during exercise;– are unable to reach 85% of their predicted maximum

heart rate during exercise.• Isotopic scanning: Thallium scanning can determine the

ventricular ejection fraction. An ejection fraction of �0.30correlates with a significantly increased risk of periopera-tive myocardial infarction.

• Transthoracic echocardiography (TTE): This can detectabnormalities of the ventricular contractility and valvefunction.

• Coronary angiography: This provides definitive evidence ofthe degree and extent of coronary occlusion and is essen-tial before coronary bypass surgery.

HypertensionHypertension is present in approximately 20% of adult patientsand the definition of hypertension has changed with greaterrealisation of the deleterious effects of even modest long-termelevation of blood pressure (BP; Table 1.5).

Mild controlled hypertension in isolation appears to poseno additional operative risk, but uncontrolled hypertension(Stage 3 or 4) has an increased risk of congestive cardiac fail-ure, myocardial ischaemia and unplanned admission to crit-ical care units perioperatively.

Antihypertensive medication should not be discontin-ued prior to surgery. However, there have been reports of significant induction hypotension in patients treated withangiotensin converting enzyme (ACE) inhibitors. Clinical

practice varies, with some authors advocating cessation ofACE inhibitors on the day prior to surgery whilst others con-tinue therapy. Elective surgery should be curtailed if the dia-stolic BP exceeds 115 mmHg as a diastolic BP �120 mmHg has a well-documented association with perioperative com-plications. In the emergency situation, intra-arterial monitor-ing and control of BP using intravenous beta-blockers orglyceryl trinitrate (GTN) should be employed. Management of hypertensive patients during surgery is complicated by their exaggerated responses to noxious stimuli such as pain orendotracheal intubation.

Management principals:• Assessment and optimisation of BP control.• Assessment of associated pathology:

– coronary disease;– congestive failure;– renal dysfunction;– peripheral vascular disease.

• Anaesthetic management (refer to Chapter 2):– accurate monitoring of BP;– management of intubation hypertension;– observation of intraoperative hypertension or signs of

ischaemia;– avoidance of large swings in BP or periods of prolonged

hypotension.• Postoperative management (refer to Chapter 3):

– optimal pain control – non-steroid anti-inflammatorydrugs (NSAIDs) should be used cautiously, if at all, inpatients on angiotensin 2 receptor blockers and diuret-ics because of a significant risk of development of renalimpairment;

– BP management prior to return of oral medication.

Congestive cardiac failureUntreated congestive cardiac failure has a high associationwith postoperative morbidity and is a contraindication to elect-ive surgery. If emergency surgery is necessary in the presenceof poorly controlled heart failure, monitoring of left and rightventricular filling pressures will be necessary and consider-ation should be given to postoperative respiratory support.Patients with treated cardiac failure are at low risk of complica-tions, provided medication is maintained over the preopera-tive period. The fluid shifts associated with spinal and epiduralanaesthesia may precipitate pulmonary oedema in the preop-erative period and may be controlled by leg elevation or ban-daging, as well as judicious doses of vasoconstrictors such asmetaraminol.

Valvular heart diseaseUndetected valvular heart disease, especially aortic stenosis,has a high association with postoperative morbidity. In add-ition to impaired cardiac function, associated organ pathologysuch as pulmonary, hepatic and renal dysfunction may occur.Clinical assessment is based on history, exercise tolerance andauscultation. The New York Heart Association classification

4 Fundamentals of surgical practice

Table 1.5. Classification of hypertension.

Systolic Diastolic

Category (mmHg) (mmHg)

Normal �130 �85

High normal 130–139 85–89

Hypertension

Stage 1 (mild) 140–159 90–99

Stage 2 (moderate) 160–179 100–109

Stage 3 (severe) 180–209 110–119

Stage 4 (very severe) �210 �120

of patients with heart disease is a useful index of functionalimpairment (Table 1.6).

Assessment requires either TTE, TOE or cardiac catheteri-sation to determine pressure gradients across the valves. In general, preoperative management of the patient with valve disease involves prophylactic antibiotics, because ofthe increased risk of bacterial endocarditis, and meticulousattention to fluid management, as well as specific therapy forindividual heart problems.

Respiratory system

Risk factorsA list of risk factors which increase the incidence of post-operative pulmonary complications exists in an analogousmanner to that for cardiac complications.• History:

– preoperative symptoms of respiratory disease,– preoperative history of chronic obstructive airways dis-

ease (COAD),– preoperative productive cough,– cigarette smoking,– poor nutrition,– age �60 years.

• Examination:– obesity,– abnormal chest examination,– abnormal chest X-ray.

• Surgery and anaesthesia:– thoracic and upper abdominal surgery,– anaesthesia �3 h.

Certain techniques improve preoperative pulmonary per-formance and reduce the incidence of complications:• bronchodilator therapy,• pre- and postoperative chest physiotherapy,• optimal analgesia,• cessation of smoking 6–8 weeks prior to major surgery,• use of the incentive spirometer as an adjunct to

physiotherapy,• early ambulation,• prophylactic antibiotics if chest infection is present.

Assessment of respiratory functionClinical history should elicit exercise tolerance, type and prod-uctivity of cough and any precipitating factors of respiratorydistress, such as lying flat. Examination includes auscultation

and percussion of the chest and an assessment of airwaypatency. Bedside clinical testing of respiratory function pro-vides valuable information, especially in situations wherelaboratory testing may not be readily available:• breathlessness on walking a few metres around the ward

usually represents decreased cardiopulmonary reserve;• inability to count beyond 20 at a single inspiration quanti-

fies dyspnoea;• accompanying the patient during stair climbing verifies

the degree of exertional dyspnoea.Laboratory testing accurately quantifies the degree of impair-ment as well as recording effects of therapy such as bron-chodilator administration. The commonest tests are:• Spirometry which measures the volumes of exhaled gas per

unit time. The commonly assessed parameters are:– forced vital capacity (FVC);– forced expiratory volume (FEV1);– FEV/FVC ratio: usually �85%; �50% indicates that post-

operative ventilation is more likely;– maximum mid-expiratory flow rate (MMEFR);– peak expiratory flow rate (PEFR) which measures airflow

obstruction at high flow rates.• Arterial blood gas estimation provides information as to

baseline levels of gas transfer and helps guide therapy.Indicators of significant risk of postoperative respiratory fail-ure are:• respiratory rate �40/min,• PaCO2 � 50 mmHg,• PaO2 � 60 mmHg,• gradient � 300 mmHg on 100% oxygen,• Vd/Vt ratio 0.6,• FVC � 15 ml/kg,• FEV1 � 50% predicted value.

The COADThe term COAD includes a group of destructive lung diseasesgenerally caused by smoking and characterised by dyspnoeaof progressive severity, airflow obstruction and cough. Thedestructive process leads to hypoxaemia and hypercarbia.Historically, the disease was separated into chronic bronchitis(predominantly obstructive disease) and emphysema (pre-dominantly destructive disease), but they are now generallygrouped together, reflecting the fundamentally similar patho-physiology. Intercurrent chest infections are common andright ventricular dysfunction is seen in up to 50% of patientswith COAD.

Any increase in quantity or change in appearance of sputummay be indicative of developing infection. Assessment of theseverity of COAD requires knowledge of the degree of exerciseimpairment. The distance a patient can walk on the flat orthe number of flights of stairs which can be climbed beforedeveloping dyspnoea gives a measure of exercise tolerance.Other conditions such as hip disease or intermittent claudi-cation can limit the value of this clinical test. Some anaes-thetists walk up the stairs with patients to verify these facts.

Preoperative management 5

Table 1.6. New York Heart Association classification ofpatients with heart disease.

1 Asymptomatic

2 Symptoms with ordinary activity but comfortable at rest

3 Symptoms with minimal activity but comfortable at rest

4 Symptoms at rest

Tests of airflow limitation quantitate the level of impair-ment. FEV1 is the most commonly used although the MMEFRis more sensitive. The response to �2 selective agonists such assalbutamol should be ascertained prior to surgery. As withasthma, the patient should take their aerosol with them to theoperating room for use prior to surgery. Phosphodiesteraseinhibitors (theophyline) are second-line therapy as the narrowtherapeutic dose range means toxic symptoms may occur.Ipratropium bromide (atrovent) combined with selective �2agonists may give improved and prolonged benefit comparedwith �2 agonists alone. Intraoperative arterial blood gas moni-toring is advisable in patients with severe COAD and baselinevalues on room air, prior to surgery and assist planning post-operative care.

Patients with COAD are prone to desaturation during sleepand this has important implications for postoperative care andmay contribute to the incidence of myocardial infarction inthe early postoperative days. Physiotherapy commencing pre-operatively significantly improves the outcome, especially inpatients with significant sputum production. Regional anaes-thesia, particularly for lower abdominal, limb and vascularsurgery, is useful in this group of patients.

AsthmaAsthma is a syndrome of heightened bronchial reactivity to avariety of stimuli, resulting in airflow obstruction of variableseverity. The overall incidence in the population is 4% and thisis increasing worldwide. Therapy involves the use of bron-chodilators alone or in combination with anti-inflammatoryagents. Maintenance steroid use is increasing in asthma medi-cation and inhaled steroids cause fewer systemic problemsthan oral steroids due to their poor absorption from the lungs.Suppression of adrenal function may occur with oral steroidtherapy and this may last for up to 3 years after cessation oftherapy.

Clinical assessmentIn known asthmatics, it is essential to elicit provoking fac-tors, frequency of attacks, length of hospitalisation requiredand the drug therapy, especially steroid use. Physical exam-ination may be unremarkable between attacks.

Respiratory function testSpirometry should be performed to assess FVC and FEV1.Spirometry also allows assessment of the response to bron-chodilators. Arterial blood gases and chest X-rays are notroutinely necessary. Some centres recommend routine fullblood testing to detect eosinophilia but this is not universal.

Preoperative preparation requires optimisation of drug ther-apy and estimation of baseline respiratory function, allowinggrading of severity of asthma:• Mild asthma (no hospitalisation): Maintain routine ther-

apy and administer selective �2-agonist (salbutamol) viaaerosol prior to surgery.

• Moderate asthma (some functional impairment, routine useof bronchodilators): Maintain routine therapy and adminis-ter selective �2-agonist (salbutamol) via nebuliser prior tosurgery.

• Severe asthma (significant impairment, current bron-choconstriction): Corticosteroids should be used (e.g. hydro-cortisone 1–3 mg/kg) 2 h prior to surgery in addition toinhaled �2-agonist therapy.

Upper respiratory tract infectionsThe significance of upper respiratory tract infections (URTIs)on the outcome of surgery has been argued. There is anincrease in bronchial reactivity associated with URTI and thuspostponement of surgery in asthmatic patients is prudent. Innon-asthmatic adults, no effect on outcome has been found.In children, no agreement has been reached on the advisabil-ity of postponement of elective surgery during URTIs.

Obstructive sleep apnoeaPatients with obstructive sleep apnoea (OSA) have episodes ofupper airways obstruction associated with arterial oxygendesaturation. OSA is defined as the cessation of airflow forlonger than 10 s despite continued ventilatory efforts, at least 5times per hour of sleep. Desaturation during sleep results inbradycardia and ventricular ectopic beats and eventually sys-temic and pulmonary hypertension develops. The incidenceof OSA appears to be increasing with approximately 2–4% ofthe population affected. It is commoner in males and in theobese (�60% with OSA are obese). OSA causes episodes ofdaytime sleepiness and an increase in accidental injuries. Atthe preoperative interview patients or their partners may vol-unteer symptoms, but all obese patients should be questionedfor occult OSA. Sleep studies should be performed to quanti-tate the severity of OSA and evaluate therapy prior to surgery. Ifsurgery cannot be delayed, the patient should be assumed tohave OSA and managed accordingly. Regional anaesthesia, ifpractical, is a good option and sedative drugs, particularly ben-zodiazepines should be avoided. If patients have their owncontinuous positive airway pressure (CPAP) apparatus thisshould be brought to hospital with them prior to surgery andpostoperative care in a high dependancy unit is advisable.

Central nervous system

EpilepsyPatients with grand mal epilepsy are at increased risk of fit-ting in the perioperative period due to:• inadequate blood levels of anticoaconvulsants because of

fasting or impaired absorption due to surgical pathology;• excitatory effects of some anaesthetic agents or delay in

recommencing oral medications.At the preoperative interview the frequency of attacks, any pre-cipitating circumstances, and current medications should bedocumented. Anti-epileptic agents should be taken on themorning of surgery and if oral therapy cannot be resumed

6 Fundamentals of surgical practice

postoperatively, parenteral anti-epileptic agents should becommenced.

DementiaThe increasing population of elderly patients has increasedthe number of patients with Alzheimer’s dementia and vascular dementia presenting for surgery. The commonestco-morbidities encountered in dementia patients are COADand atherosclerotic cardiovascular disease. It is common for adeterioration in cognitive function to occur in the periopera-tive period and this may take weeks to resolve. Neurolepticdrugs appear to increase the incidence of cognitive disordersperioperatively. Patients with chronic brain syndromes poseseveral problems in preoperative assessment:• Consent, to be valid, should be signed by the person respon-

sible under the relevant law of the jurisdiction involved or bereferred to the local Guardianship Board (or similar).

• Accurate history taking may be impossible and medicationsmay not be remembered. Increased time may be required to allow access to previous medical histories from other hospitals.

• Patient anxiety may lead to extreme agitation and restless-ness. Sedative agents injudiciously given may worsen thisagitation.

• Underlying pathological processes affecting other organsystems (alcoholism, severe peripheral vascular disease orchronic syphilis) or physical factors (head injury with flexiondeformities, bed sores or low-grade urinary tract infections)must be taken into account during surgery and anaesthesia.

Renal system

Chronic renal failurePatients with chronic renal failure pose many problems forthe surgeon and anaesthetist because of the frequency withwhich surgery is necessary in these patients and the manyassociated medical problems present in this group:• Cardiovascular:

– Hypertension and associated complications.– Chronic anaemia due to ureamia and reduced ery-

thoropoietin levels. Haemoglobin (Hb) levels of 7–10 g/lare normal in patients with chronic renal failure and inju-dicious transfusion may precipitate cardiac failure. Thepatient’s weight is a useful guide to the level of hydrationin an emergency when dialysis may not be possible priorto surgery.

• Diabetes:– Associated retinopathy, microvascular disease or auto-

nomic dysfunction should be considered.• Acid–base and metabolic:

– Metabolic acidosis.– Hyperkalaemia: Serum potassium �6 mmol/l requires

dialysis prior to surgery to prevent further rises dur-ing the preoperative period. Factors which may increaseserum potassium include the use of suxamethonium,

administration of blood and hypoventilation. In all butdire emergencies, correction of potassium prior to sur-gery can be accomplished by dialysis, glucose–insulintherapy or Resonium enemas.

– Hypocalcaemia due to vitamin D deficiency.– Hypermagnesaemia.– Inability to manage a water load.

• Immune system:– Concurrent use of immunosuppressants and decreased

phagocyte effectiveness combine to increase periopera-tive risk of sepsis.

• Coagulation:– Coagulopathy may be present due to reduced platelet

adhesiveness. International Normalised Ratio (INR) andantiprothrombin time (APTT) are usually normal.

• Arteriovenous fistula:– The presence of vascular access fistulas for haemodialysis

in the upper limbs limits venous access for non-invasiveblood pressure (NIBP) monitoring and drug administra-tion during anaesthesia and recovery. Protection of thefunction of these fistulas from pressure and periods ofhypotension (which may cause clotting of the fistulae)requires continual vigilance until the patient has fullyregained consciousness.

• Miscellaneous:– Delayed gastric emptying (uraemia) and increased gas-

tric acidity increase the risk of reflux and aspiration.Preoperative use of H2 receptor blockers or proton pumpinhibitors is recommended.

• Medications:– The majority of renal patients have associated hyper-

tension and medication should be continued throughthe preoperative period. Oral hypoglycaemics should be discontinued the night before surgery and insulinshould be managed as discussed in the section on dia-betes. Renal failure decreases clearance (but not loadingdose) of many drugs. If gentamycin or other aminogly-cosides are necessary, blood levels should be monitoredperioperatively. Metabolic changes in chronic renal failure affect clearance of NSAID’s, pancuronium, peth-idine (norpethidine accumulation) and enflurane whichshould be avoided.

• Transplanted patients:– Immunosuppressants increase infection risk, steroids

increase osteoporosis and risk of pathological fractures.The transplanted kidney is at risk of physical damageduring positioning or rejection if immunosuppressantsare withheld perioperatively.

Liver

The commonest causes of liver impairment are viral (hepa-titis B and C), toxicity (alcohol, paracetamol) and auto-immune disease (primary biliary cirrhosis, autoimmune hepatitis).

Preoperative management 7

Liver failure can be classified by the acuity (i.e. the inter-val between the onset of jaundice and the development ofencephalopathy:• Hyperacute: within 7 days.• Acute: within 7–28 days.• Subacute: within 28 days to 6 months.• Chronic: �6 months.Pathophysiological features include:• Haematological: coagulation should be checked because

many patients will have impaired coagulation due to clot-ting factor deficiency and impaired platelet function.

• Respiratory: pleural effusions or ascites may impair breath-ing and increase aspiration risk.

• Cardiovascular: cardiomyopathy (alcoholic and haemochro-matosis) should be excluded.

• CNS: encephalopathy is commonest in acute and can begraded:– Grade 0: alert and orientated.– Grade 1: drowsy but orientated.– Grade 2: drowsy and disorientated.– Grade 3: agitated and aggressive.– Grade 4: unrousable to deep pain.

• Pharmacological effects include prolongation of musclerelaxants (suxamethonium, mivacurium, vecuronium androcuronium), as well as accumulation of fentanyl and mor-phine. Non-steroidal agents should be avoided because ofthe increased risk of gastrointestinal (GI) bleeding in patientswith impaired coagulation.

Assessment of liver function: Serum bilirubin and albuminplus prothrombin time (PT) are markers of global hepatic dys-function, whilst elevated levels of transaminases can occurwith minor liver damage. The Childs–Pugh classification forpatients with cirrhosis indicates an increasing chance ofhepatic failure.

Endocrine system

DiabetesApproximately 2.5% of the population have diabetes withthe incidence rising in patients �80 years old. The major-ity (�90%) have non-insulin-dependent diabetes mellitus(NIDDM or Type II diabetes).

Assessment of the diabetic patient undergoing surgeryshould include:• Cardiovascular system: Microvascular disease is widespread

in diabetic patients with between 15% and 60% of insulin-dependent diabetics having ECG changes. This microvas-cular disease is frequently associated with left ventriculardysfunction.

• Hypertension: This is present in over 60% of diabetic patients.Autonomic neuropathy is an uncommon but serious com-plication of diabetes with impaired cardiovascular responsesto exercise and stress. Orthostatic hypotension is a reliableindicator of the presence of autonomic neuropathy.

• Peripheral vascular disease: This is frequently present andthese patients are at risk of vascular occlusion during periods of hypotension or hypovolaemia.

• Renal disease: This is common in diabetic patients withglomerulosclerosis, papillary necrosis and ultimatelychronic renal failure.

Preoperative management of blood glucose is necessary toprevent ketosis and acidosis, volume depletion due to osmoticdiuresis or complications associated with undetected hypogly-caemia, especially brain cell damage or pulmonary aspiration,whilst unconscious. Blood sugar should be estimated, usuallyby the finger-prick method, since urine sugar estimations aretoo unreliable during periods of fluctuating blood sugar andvariable urine output.• For major surgery in insulin-dependent diabetes patients:

insulin–dextrose–potassium infusion is a reliable regimen.Frequent blood sugar monitoring is important to avoidpotentially dangerous periods of hypoglycaemia. Follow-upin the perioperative period and consultation between anaes-thetist, surgeon and physician is essential.

• For minor surgery in insulin-dependent diabetes patients:half of the normal morning insulin requirement is givenand a 5% dextrose infusion is commenced. If oral feedingdoes not recommence within 4–6 h, conversion to the regi-men as for major surgery should be instituted.

• For minor surgery in NIDDM patients: withhold oral hypo-glycaemic agent on the morning of surgery. Blood sugarshould be monitored throughout the preoperative period.

• Emergency surgery in diabetics: is frequently undertakenagainst a background of either infection or acidosis andhyperglycaemia. Meticulous attention to blood glucose con-trol and fluid balance are essential.

HypothyroidismSubclinical hypothyroidism affects an estimated 2–8% of thepopulation and this incidence rises to 16% in females over 60years. Patients with clinical hypothyroidism should be ren-dered euthyroid prior to elective surgery, because of theirincreased sensitivity to anaesthetic agents which may causedelayed awakening. L-thyroxine can be given as 50 �g/day ini-tially followed by 150–200 �g/day as a maintenance dose. Inelderly patients or those with coronary disease, reduced dosesare recommended.

HyperthyroidismMedical control of hyperthyroidism using beta-blockers andantithyroid drugs (propylthiouracil or similar) is necessaryprior to elective surgery to avoid serious complications such as:• Thyroid storm, which is an acute episode of profound thy-

roid hyperactivity associated with tachycardia, pyrexia andcardiac arrhythmias. If untreated, this condition has a highmortality rate.

• Precipitation of angina, myocardial infarction or cardiacfailure.

8 Fundamentals of surgical practice

• Tachyarrhythmias: episodes of paroxysmal atrial fibrilla-tion (AF) occur in nearly 25% of hyperthyroid patients.

If emergency surgery is indicated in hyperthyroid patients,the following precautions are necessary:• intravenous administration of antithyroid drugs;• indwelling arterial monitoring;• sedating premedication to allay anxiety;• avoidance of drugs which may provoke tachycardia, such

as ketamine, pancuronium, atropine;• use of beta-blockade to control heart rate during endotra-

cheal intubation and surgical incision;• adequate depth of anaesthesia to ablate noxious stimuli;• good postoperative pain control.

Adrenal insufficiencyTwo types of adrenal insufficiency exist:• Primary (Addison’s disease) with inadequate levels of gluco-

corticoids, mineralocorticoids and androgens. Signs includefatigue, anorexia, cutaneous pigmentation and hypotensionwith hyponatremia and hyperkalaemia.

• Secondary due to inadequate levels of corticotropin-releasing hormone (CRH) or adrenocorticotrophic hor-mone (ACTH) due to corticosteroid use or hypothalamicor pituitary disease.

Normal cortisol secretion is 25–30 mg/day rising to 75–150 mgwith stress such as surgery and peaking at 200–500 mg/daywith severe stress. A dose equivalent of prednisolone20 mg/day for at least 3 weeks in the last year will produce someadrenal suppression. Recommendations for steroid replace-ment perioperatively vary widely.

A suggested regime is:• minor surgery IV hydrocortisone 25 mg;• major surgery:

– intraoperatively: IV hydrocortisone 75–150 mg;– postoperatively: IV hydrocortisone 50 mg 8 h for 1 day,

then 25 mg 8 h for 1 day.Acute Addisonian crisis is rare and presents with:• lethargy, weakness;• severe nausea, vomiting and abdominal pain;• hypotension with hypovolaemia.Management involves treatment of cause (if possible), glu-cocorticoids and fluids. Inotropes are relatively ineffective inAddisonian crisis if steroids are not given.

PhaeochromocytomaThese are catecholamine secreting tumours of chromatin cells.Noradrenaline secretion predominates in most cases, but in15% of cases adrenaline secretion is predominant. Presentingsigns include hypertension either constant or paroxysmal,headache, sweating and palpitations. Catecholamine-inducedcardiomyopathy may also be present. Management prior tosurgery involves alpha-blockade with phenoxybenzamine orprazocin for between 3 days and 2 weeks. Beta-blockers may be added to alpha-blockade if necessary. Echocardiography toexclude cardiomyopathy is advisable.

Haematology

AnaemiaChronic anaemia (Hb � 9 g/l) should be corrected prior toelective surgery, because the anaemic patient has reducedoxygen carrying capacity reserve to compensate for intraop-erative blood loss. In addition, compensatory mechanismsfor the reduced oxygen carrying capacity, such as:• Increased cardiac output:

– peripheral vasodilation (microvascular control mechanisms);

– reduced blood viscosity.• Increased oxygen extraction:

– shift of haemoglobin dissociation curve to the right;– local tissue acidosis;

may encroach on cardiac reserve. Correction to Hb 10 g/l isadvised using supplemental iron for elective surgery. If transfu-sion to correct chronic anaemia is necessary when surgery ismore urgent, caution is required if �1 unit/day is administeredin case pulmonary oedema is precipitated, and packed cells areused in preference to whole blood. Intraoperative blood lossshould be promptly replaced and factors increasing post-operative oxygen requirements (especially shivering) shouldbe avoided.

Patients with sickle cell anaemia are at increased risk ofsickle cell crises during anaesthesia:• hypoxic episodes,• tourniquet use,• dehydration associated with prolonged fasting of increased

fluid losses.Although hydroxyurea has been used to stimulate HbF pro-duction which reduces the incidence and severity of sickle cellcrises, this work is still in the experimental stages due to con-cerns regarding mutagenesis and leukemogenesis. Patientsfrom countries with endemic sickle cell disease should bescreened prior to surgery.

Coagulation and haemostasisCoagulation disordersIt is vital to diagnose and appropriately manage patients withthese disorders. Some of them are obscure, some of them canbe elucidated from the history. A history must be taken of pre-vious operations or spontaneous episodes of bleeding, perhapsfrom the gums or following trivial injuries. Drug and family his-tory are also essential. Bruising or petechiae may be present onexamination. Detection of some conditions will emerge fromresults of simple routine tests such as PT, partial thromboplas-tin time (PTT), thrombin time (TT) and platelet count.

In most cases the expert help of a clinical haematologistwill be required. In cases that are difficult to interpret, it isbetter to anticipate and take precautionary measures than tocall for help when disaster has struck.

Bleeding disorders may be congenital or acquired:• Congenital defects include clotting factors as in haemophilia

and von Willebrand’s disease, congenital platelet disorders

Preoperative management 9

and vessel wall defects such as hereditary haemorrhagictelangiectasia.

• Acquired disorders include clotting factor disorders result-ing from drugs such as anticoagulants, antibiotics and liverdisease. Disseminated intravascular coagulopathy (DIC)may complicate sepsis, haemolysis, antibody–antigencomplex reactions and advanced neoplasia. Platelet func-tion is notably reduced by aspirin and NSAIDs and in liver,kidney and myeloproliferative disorders. Platelets num-bers are reduced in autoimmune thrombocytopaenia,hypersplenism and aplastic anaemia. The integrity of thevessel walls is reduced after taking steroids, in vasculitisand in malnutrition.

Patients on maintenance treatment with anticoagulants whoare to undergo operation are at risk from bleeding but if theiranticoagulants are stopped they are at risk of thrombosis.Before minor operations it is usual to stop oral warfarin for 2 days preoperatively and to start it immediately afterwards.Those having extensive procedures or with, for example, pros-thetic heart valves, should stop warfarin and be maintainedon heparin subcutaneously or by intravenous infusion underthe supervision of a haematologist. In some cases, an oper-ation may need to be performed as an emergency, or a patientmay have bled as a result of taking anticoagulants. In thesecases, the anticoagulant effects should be reversed with vita-min K, fresh frozen plasma (FFP) or concentrated clottingfactors – again under the guidance of a haematologist.

Patients with coagulation disorders usually need to haveblood or blood products available during surgical procedures,such as plasma-reduced cells, platelet transfusions, FFP, cryo-precipitate (which contains fibrinogen, fibronectin and factorVIII) or coagulation factor concentrates. They may, however,have atypical antibodies.

L IFESTYLE INFLUENCES ON ANAESTHETIC RISK

AlcoholExcessive alcohol ingestion leads to a spectrum of pathologydepending on the extent and chronicity of the problem:• Increased cellular tolerance of drugs means that higher

than expected doses of anaesthetic agents will be required.• Withdrawal symptoms in the postoperative period require

aggressive treatment to prevent the patient from injuringthemselves or staff members. Symptoms include: disorien-tation, hallucinations, tachycardia, hypertension and grandmal convulsions. Management includes thiamine, benzodi-azepine sedation and beta-blockers. Mild alcohol with-drawal symptoms occurring within 6–8 h of abstinencerequire no specific therapy.

Potential perioperative problems include:• cellular tolerance leading to higher anaesthetic

requirements,• chronic brain syndrome (alcoholic dementia),• clotting abnormalities,

• increased risk of infection,• poor wound healing,• acute withdrawal syndrome (delerium tremens),• agitation and self-harm,• wound disruption,• cardiovascular instability,• bleeding varices.

Morbid obesityObesity is an increasing health problem worldwide. It isdefined as having 25–30% greater than ideal body weight orbody mass index (BMI) �30. The BMI is defined as weight(kg) divided by height (m) squared. Morbid obesity may bedefined as being 100% greater than ideal body weight orBMI � 35. Morbid obesity is associated with a significantdiminution of physiological reserve and an increase in associated pathological conditions including hypertension,coronary artery disease, diabetes and oesophageal reflux.Cardiovascular performance shows impaired diastolic fillingand reduced rise in ejection fraction with exercise comparedwith non-obese patients. These associated medical condi-tions pose increased difficulties during surgery and anaes-thesia. Osteoarthritis, hiatus hernia and gallbladder diseaseare common and frequently require surgery.

Perioperative problems associated with morbid obesityInduction• Venous access is often difficult and a central line may be

required for access.• Accurate BP monitoring is difficult and wide BP cuffs will

be required if non-invasive monitoring is used. An arterialline may provide more reliable readings in this situation.

• Difficulty in intubation.

Intraoperative problems• Patient positioning.• Drug dosage to ensure adequate depth of anaesthesia.

Postoperative problems• Respiratory insufficiency due to mass loading of chest wall

and abdomen plus reduced vital capacity.• The high incidence of OSA. Patients with morbid obesity and

OSA have a 20–25% incidence of daytime hypoxia leading topulmonary hypertension and 50% incidence of hypercarbia.

• Increased incidence of deep vein thrombosis (DVT).

SmokingSmoking significantly increases perioperative risk. Elevatedcarboxyhaemoglobin levels due to inhaled carbon monox-ide persist for up to 12 h after cessation of smoking andlaryngeal irritability and bronchial reactivity are enhancedby smoking. Co-existing smoking-induced pathology iscommon and includes:• hypertension,• ischaemic heart disease and peripheral vascular disease,• COAD.

10 Fundamentals of surgical practice

Patients should be advised to cease smoking prior to surgery,however, compliance is poor and no decrease in postoperativecomplications has been found unless smoking is stopped�8 weeks prior to surgery. Careful assessment is necessarybecause symptoms of the presenting illness may mask those ofother cigarette-induced disease processes, with angina, inter-mittent claudication and exertional dyspnoea being commonexamples.

Non-prescription drugs and substance abuseThe large number of ‘recreational’ and addictive drugs haveimplications for anaesthesia and surgery:• Patients using injectable agents have an increased risk of

blood-borne infections, including HIV, hepatitis and bac-terial endocarditis.

• Withdrawal symptoms may appear and include violentand aggressive behaviour, or delusional and hallucinatorybehaviour. A high clinical index of suspicion is necessaryto diagnose drug withdrawal.

• Interactions between therapeutic and non-prescriptiondrugs may complicate management, for example, opioidresistance in narcotics abuse, hypertension and tachycar-dia with amphetamine use and resistance to anaestheticagents with sedative abuse.

• Venous access may be particularly difficult, especially inthe hypovolaemic chronic drug user.

• Solvent inhalation sensitises the myocardium to arrhyth-mias especially with inhalational anaesthetic agents.

Herbal productsBecause herbal products are not considered ‘drugs’ by mostpatients, the use of these products may not be volunteered at the preoperative interview. The use of these substances isincreasing worldwide with up to 22% of patients (USA) takingsome form of herbal supplement. Although most appear tohave no effect on the conduct of surgery or anaesthesia, severalcan have significant effects (Table 1.7) and should be ceased

prior to surgery whenever possible. In addition, many may betaken as individually prepared preparations and hence the‘dose’ consumed may vary widely.

CONCURRENT DRUG TREATMENT

AnticoagulantsIncreasing numbers of patients are on long-term anticoagu-lation therapy because of chronic AF, pacemaker insertion orfollowing valve replacement. The risk of embolisation if coagu-lation is withdrawn is used to guide perioperative manage-ment (Tables 1.9–1.11).

Antiplatelet drugsAntiplatelet drugs pose a unique risk, especially with emer-gency surgery, because of the inability to reverse the effect ofthe commonly available antiplatelet drugs such as cliopidogrelor ticlopodidine. For elective surgery, cessation between 7(clopidogrel) and 10 (ticlopidine) days prior to surgery is recommended.

SteroidsAdrenal suppression from oral steroid use (�2 weeks in thepreceding 9 months) may cause a potentially fatal Addisoniancrisis perioperatively if additional glucocorticoids are not given.Although there is no proven benefit from supra-physiologicaldosage, underdosage is disadvantageous. A typical regimen ishydrocortisone 100 mg IV twice daily tapering off by 25% perday over the next few days although lower doses are permissi-ble with uncomplicated minor surgery (e.g. inguinal herniarepair).

ImmunosuppressantsImmunosuppressant therapy poses several problems for thesurgeon and anaesthetist:• prolongs effect of suxamethonium,• increases risk of wound infection,• delays wound healing.

Preoperative management 11

Table 1.7. Herbal products affecting anaesthesia or surgery.

Herb Concern

Echinacea purpura (echinacea) Immune suppression, chronic use hepatotoxic may decrease steroid effectiveness

Allium sativum (garlic) ↑ bleeding (affects platelet aggregation)Ginkgo biloba (ginkgo) ↑ bleeding (patients on anticoagulants)Panax ginseng (ginseng) Low blood sugar, tachycardia, ?bleeding ↑ bleeding (patients on anticoagulants)Glycyrrhiza glabra (licorice) Hypertension, oedema, low K� contraindicated in renal/hepatic dysfunction

Goldenseal Used as a diuretic, but water excretion predominates worsening hypertension

Piper methysticum (kava) Prolongs anaesthesia

Mahuang Arrhythmias, hypertension, death reported drug interactions

(Ephedra sinica)

Hyperium perforatum (St John’s wort) ↓ effect warfarin, steroids ↓ effect HIV protease inhibitorsValeriana officinalis (valerian) Prolonged anaesthesia, withdrawal syndrome

Vitamin E Possible thyroid effect, may increase bleeding

Zimber officinale (ginger) Antiplatelet effects

Tricyclic antidepressantsThe complications associated with administering anaesthe-sia to a patient taking psychotropic drugs must be weighedagainst possible complications from their cessation.• Antidepressants should only be discontinued in consult-

ation with the treating psychiatrist.• Monoamine oxidase inhibitors (MAOI): In general, following

consultation with the treating psychiatrist, MAOI should bediscontinued 2–3 weeks prior to surgery. This allows regener-ation of adequate levels of monoamine oxidase, otherwise,excitatory effects, such as hypertension or convulsions, have

resulted from administration of pethidine to patients treatedwith MAOI. Hypertensive crises may occur when vasopres-sors are administered to patients on MAOIs. If surgery inpatients on ongoing MAOI therapy is necessary or for emer-gency surgery, the following guidelines should be employed:

• Preoperative consultation with the treating psychiatrist.• Benzodiazepine premedication.• Avoid halothane, pethidine.• If vasopressors are necessary, avoid indirect-acting pres-

sors (metaraminol) and use fluids and posture whereverpossible. Carefully titrate small doses of direct-acting vaso-constrictors (methoxamine or phenylephrine) if necessary.

• Suxamethonium effect may be prolonged due to decreasedcholinesterase levels.

12 Fundamentals of surgical practice

Table 1.10. Recommendations for perioperative anticoagulation in the low-risk group.

Day-4 Cease warfarin (if INR � 3.5 cease 5 days

preoperatively)

Day-3, -2, -1 No anticoagulation

Day-0 Measure INR on morning of surgery. If INR �

2.0 postpone or transfuse FFP

Postoperative Use heparin/LMWH (if indicated) for DVT

prophylaxis

Measure INR

Re-commence warfarin when oral fluids

tolerated and monitor INR

Table 1.8. Drug interactions and anaesthesia.

Drug Effect

AIDs Rx Increased sensitivity to midazolam

and fentanyl

Angiotensin2 blockers May get hypotension at induction

Anticonvulsants Liver enzyme induction may increase

dose requirements for lithium may

potentiate non-depolarising neuro-

muscular blocking drugs

Diuretics Hypokaelaemia may increase sensi-

tivity to non-depolarising neuromus-

cular blocking drugs

MAOI Pethidine may produce hypertensive

crises

Platelet function drugs Increased bleeding with spinal/

epiduralsTable 1.11. Recommendations for perioperative anticoagulation in the high-risk group.

Day-4 Cease warfarin (if INR � 3.5 cease

5 days preoperatively)

Day-3 (full-dose When INR � 2.0 commence UFH (treat

UFH) as in patient) cease 6 h prior to surgery

Day-3 (LMWH) When INR � 2.0 commence LMWH.

Enoxaprin 1 mg bd (mechanical

valves, �100 kg, extensive DVT), other-

wise 1.5 mg daily

Day-2 As per Day-3

Day-1 (LMWH) Do not give LMWH � 18 h prior to sur-

gery (or �24 h spinal/epidural planned)

Day-0 Measure INR on morning of surgery. If

INR � 2.0 postpone or transfuse FFP

Postoperative Measure INR

Re-commence warfarin when oral fluids

tolerated and monitor INR

Use UFH or LMWH until oral fluids

tolerated

titrate APTT to 50–70 s (48 h)

then APTT 50–75 s until oral fluids

tolerated

UFH: unfractionated heparin.

Table 1.9. Risk of thromboembolism if anticoagulation is ceased.

Low AF/cardiomyopathy without stroke or systemic

embolisation within 12 months

Biological heart valves (after first 3/12)

Post vascular stent insertion (after first 3/12)

Non-recurrent systemic arterial emboli

Venous thrombosis NOT within last 3/12 and without

other risk factors:

– hypercoagulable state

– recurrent thrombosis

– malignancy

– preoperative immobility

High AF/Cardiomyopathy with stroke or systemic embolisa-

tion within 12 months

Biological heart valves (within first 3/12)

Post vascular stent (within first 3/12)

Mechanical aortic or mitral valve

Recurrent systemic arterial emboli

Venous thrombosis/pulmonary embolism in the last

month*

*consider vena caval filter.

Oral contraceptivesThe use of the progesterone-only pill poses no documentedproblems during surgery. However, the combination oestrogen-progesterone pill should be discontinued 6 weeks prior to elective surgery because of the increased risk of DVT, espe-cially in women who smoke. When emergency surgery is necessary, additional thomboembolism prophylaxis isrequired. In all cases, the patient must be advised to use alter-nate forms of contraception as the reliability of oral absorp-tion is affected by fasting, perioperative nausea and vomitingand any antibiotic-induced diarrhoea (Table 1.8).

PROPHYLAXIS OF THROMBOEMBOLICDISEA SE

Preoperative management of the surgical patient includesplanning to avoid fatal complication of pulmonary thrombo-embolism. Clinically significant but non-fatal thromboem-bolism occurs in about 1 : 100 postoperative patients and fatalpulmonary embolism in 1 : 1000.

The origin of the pulmonary embolus is usually thrombosisin the veins of the calf muscles, but thrombosis may spread tothe iliofemoral veins and the pelvic veins. The development ofvenous thrombosis in these veins is usually silent and mayonly manifest itself as an episode of pulmonary embolism.Hence the emphasis on prophylaxis to prevent this seriouscomplication.

Many studies have defined a number of risk factors whichpredispose to the development of pulmonary embolism:• age �40 years;• obesity;• immobilisation;• previous DVT;• general anaesthetic;• major abdominal/orthopaedic surgery;• pregnancy/postpartum;• malignancy, particularly ovarian and pancreatic cancer;• hypercoaguable states, for example, deficiency of antithrom-

bin 3, protein C or protein S;• medical illness, including myocardial ischaemia, respira-

tory insufficiency.Surgical patients can be divided into low-, medium- and high-risk groups for venous thrombosis and pulmonary embolism.A typical low-risk patient will be:• aged �40 years;• have surgery lasting �30 min, particularly avoiding general

anaesthetic;• rapidly mobilised postoperatively;• have no other risk factors.A typical moderate-risk patient will be:• aged �40 years;• show moderate obesity;• need abdominal operation requiring general anaesthetic;• have one other risk factor.

A typical high-risk patient will be:• middle-aged or elderly, undergoing major surgery

(orthopaedic or cancer surgery);• need prolonged mobilisation;• may have pelvic trauma or pelvic surgery;• may have suffered orthopaedic trauma generally: for

example, fractured neck of femur;• have multiple risk factors.All moderate- to high-risk patients should receive prophylaxis.It is not easy to categorise every patient and when in doubtprophylaxis against thromboembolism should be instituted.

Methods of prophylaxisGeneral• early ambulation;• use of venous support compression stockings, particularly

where local venous insufficiency problems exist in the limbs;• calf stimulation during operations under general

anaesthetic.These methods are sufficient prophylaxis for fit patients whofall in the low-risk group.

Moderate and high-risk patientsThese patients require pharmacological intervention withantithrombotic drugs.• Low-dose subcutaneous heparin. This has been shown to be

effective in reducing thrombosis in the peripheral veins. It isgiven at a dose of 5000 units bd subcutaneously. The maincomplications are bruising and local wound haematoma ifthe injection is given close to the site of the operative wound.The heparin at this dose does not produce any alteration instandard coagulation screening studies. The main complica-tion is the development of allergic thrombocytopaenia. Thiscondition may be associated with thrombosis and heparinmust be ceased.

• Low-molecular-weight heparin (LMWH). This may have aspecial place in orthopaedic surgery and is given as a singledaily dose. It is as effective as heparin in preventing throm-bosis and has fewer platelet side-effects. However, LMWHis expensive and is not routinely used for this reason.

• Anticoagulants. Use of the anticoagulant warfarin, eitherin low or full anticoagulation dose, has been shown to beeffective in reducing thromboembolism. However, bleed-ing complications are common and accordingly warfarinis not in regular use for this purpose.

• Antiplatelet agents. Aspirin is an effective antiplateletagent. However, it is ineffective as the sole agent to preventDVT. Dextrans act as antiplatelet agents and have beenshown to reduce the incidence of postoperative venousthrombosis. They are, however, expensive, must be givenintra-venously and are more difficult to administer thansubcutaneous heparin. Dextrans are not used routinely.

Post operative carePart of the postoperative management of the surgical patientis to check the limbs on a daily basis for the development of

Preoperative management 13

the early signs of venous thrombosis. These include calf ten-derness and leg swelling. If there is any suggestion of thedevelopment of clinical venous thrombosis, a Doppler ultra-sound and/or venogram is required to diagnose the periph-eral venous thrombosis prior to the commencement of fullanticoagulation.

PREADMISSION CLINICS

The economic and resource pressures in contemporaryhealthcare have resulted in a number of changes in clinicalpractice. These include increased use of day case (ambula-tory surgery), various domiciliary post-acute care systemsand the development of preadmission clinics to facilitatehospital admission on the day of surgery.

The aims of the preadmission clinic:• reduction in bed occupancy and thus a shorter hospital stay;• less disruption to patient’s routine;• development of guidelines for laboratory investigations to

reduce ordering of unnecessary laboratory tests;• adequate time exists between consultation and surgery for

the relevant tests to be performed and the results obtained;• fewer ‘last minute’ cancellations because of abnormal test

results;• education of patient (and family) regarding proposed sur-

gery and preparation of a plan for anaesthesia and analgesia;• to facilitate the use of the hospital for acute care only and

to encourage the management of long-term health prob-lems by community-based health services such as generalpractitioners or out-patient specialist appointments.

Where geographical distance precludes attendance of thepatient at a central preadmission clinic, the process can beundertaken by a local medical officer or peripheral hospitalwith the information faxed or E-mailed to the central hos-pital where surgery is to be undertaken.

ROUTINE INVESTIGATIONS PRIOR TO SURGERY

The ordering of laboratory tests is still largely empirical with marked differences between hospitals and individuals.Evidence-based consensus guidelines have been developed to assist decision making (National Institute for ClinicalExcellence – NICE http://www.nice.org.uk/pdf/cg3niceguide-linea4.pdf. Broad issues to consider in applying these guide-lines are:• age band,• complexity of intended surgery,• ASA classification,• nature of co-morbidity present (ASA 2).Some brief suggestions are listed in Table 1.12.

BiochemistrySignificant previously undetected abnormalities occur in �1%of cases, but occult diabetes and renal impairment are

frequently first detected on routine screening. Liver disease of sufficient severity to affect outcome from surgery will bedetected clinically, and thus liver function tests are only indi-cated when clinically detectable disease is present. Routinebiochemical testing is not indicated on asymptomaticpatients �60 years of age.

HaematologyRoutine haemoglobin estimation for clinically well patientsundergoing minor surgery is unnecessary. For major surgery,haemoglobin estimation and ‘group and save’ is advised. Thelowest level of haemoglobin at which elective surgery shouldnot proceed has been strenuously debated with 7 g/dl beingthe lowest acceptable level in most studies (when major bloodloss is not anticipated). Coagulation screening should only bedone when clinically indicated or when undetected coagu-lopathy would be a major problem, such as in neurosurgeryand heart surgery. Sickle cell status should be determined inpatients at risk.

Chest radiographThe chest radiograph is the most frequently over prescribedpreoperative investigations. In the absence of clinical indi-cations, the yield from this test is low. A chest radiograph(Fig. 1.1) should be performed only to confirm a suspectedpathological condition likely to affect outcome from surgery,such as:• cardiomegaly;• suspected pulmonary metastases and mediastinal masses;• suspected tuberculosis;• significant known lung disease such as pneumonia, pul-

monary oedema or atelectasis;• suspected thoracic pathology such as fractured ribs,

pneumothorax or pleural fluid accumulation.

14 Fundamentals of surgical practice

Table 1.12. Routine preoperative tests for asymptomaticpatients.

Chest radiograph TB suspected

Any change is symptoms/signs in

patients with proven

Lung or chest pathology

Coagulation Clinical history of abnormal bleeding

Cardiac, neurosurgery

ECG Males �45 years, females �50 years

Heart disease, hypertension,

diabetes �35 years

Significant respiratory disease

(including OSA)

Full blood examination Females

(FBE) Major surgery where significant

blood loss expected

Anaemia suspected

Sickle cell test Untested ‘at risk’ patients

Urinalysis All patients (blood, glucose, protein)

ECGsBy contrast, the ECG often provides the initial informationregarding several clinically ‘silent’ conditions which mayimpact adversely on the patient’s perioperative outcome.• myocardial infarction;• arrhythmias:

– atrial flutter or fibrillation,– ventricular ectopic beats;

• left or right ventricular hypertrophy;

• conduction problems:– arteriovenous block (1st, 2nd or 3rd degree),– Wolff–Parkinson–White syndrome,– atrial or ventricular ectopics,– prolonged ‘QT’ interval.

An ECG should be performed on all patients with known car-diovascular disease and on all asymptomatic patients �40years of age.

Cardiac function testsNuclear medicine scanning provides valuable informationof myocardial reserve in symptomatic patients. However, itshould be remembered when assessing ‘at risk’ patients, thatthe presenting condition (e.g. arthritis requiring hip replace-ment) may mask cardiac symptoms by limiting the patient’sexertion. TTE (if available) may provide valuable additionalinformation regarding valve function and contractility.

Pulmonary function testsSpirometry should be performed on patients with dyspnoeaon mild to moderate exertion.

F U RT H E R R E A D I N G

ACC/AHA Guideline update on perioperative cardiovascular

evaluation for non-cardiac surgery. American Heart Association –

www.americanheart.org

Carlisle J, Langham J, Thoms G. Guidelines for routine preoperative

testing. Br J Anaesth 93; 2004: 495–497

Chassot PG, Delabays A, Spahn DR. Preoperative evaluation of

patients with, or at risk of, coronary artery disease undergoing

non-cardiac surgery. Br J Anaesth 89; 2002: 747–759

National Institute for Clinical Excellence – NICE

http://www.nice.org.uk/pdf/cg3niceguidelinea4.pdf

Preoperative management 15

Figure 1.1. Chest radiograph showing an enlarged heart shadow.

Anaesthesia is a non-therapeutic intervention. It is particularlyimportant, therefore, to determine potential benefits and esti-mated risks. Complications of anaesthesia are poorly toleratedand it is necessary to place safety before perceived efficacy.

DEFINITIONS

AnaesthesiaAnaesthesia is a reversible state of pharmacologically con-trolled sleep with reduction in cortical activity. At sufficientanaesthetic depth there is absence of conscious awarenessand recall, and no sensory, motor or autonomic response tostimulation.

Balanced anaesthesiaThis term is used to illustrate an equilibrium between thethree constituents of an anaesthetic: anaesthesia (sleep),analgesia and paralysis. The three interact and the separa-tion is more conceptual than clinical.

SedationSedation is a state of sleepiness but preserved conscious-ness. Ideally, there is awareness and response to simplecommands with verbal contact, but also a degree of amnesiaand reduced anxiety.

STAGES OF CL INICAL ANAESTHESIA

In the 1920s four stages of progressively deeper anaes-thesia were described in relation to inhalational induction.Drugs and techniques have changed considerably since andit is difficult to distinguish these stages clearly in modernanaesthesia.

AnalgesiaThis is the stage of inhalational sedation prior to loss of consciousness.

ExcitementThe breathing slowly becomes more erratic; the airway is irri-table. There may be uncontrolled movements of the limbs.

2

Principles of AnaesthesiaCarlos MH Gómez1 and John WW Gothard21Department of Anaesthesia and Intensive Care, Charing Cross Hospital, London and 2Royal Brompton Hospital; National Heart and

Lung Institute, Imperial College School of Medicine, London

CONTENTS

Definitions 16

Stages of clinical anaesthesia 16

Awareness 17

Assessment 17History of previous anaesthesia 17Past medical history 18Drug history 18Social history 19Physical examination 19Risk stratification 20

Premedication 21

Preoperative checks 23

Induction 23Methods 23Control of the airway 23Control of breathing (ventilation) 24

Maintenance of anaesthesia 24Anaesthesia (hypnosis) 24Analgesia 25Paralysis 25Pharmacology of anaesthetic agents 25Perioperative fluid management 28

Monitoring 29Monitoring of the patient 29Monitoring of the equipment 30

Recovery 30Vasodilatation 32

Anaesthetic emergencies 33

Local anaesthetic drugs 34

Sedation 35

Regional anaesthesia 35General Aspects 36Specific techniques 36

Tourniquets 37

Ventilation 37

Further reading 38

Principles of anaesthesia 17

Surgical anaesthesiaClassically, this consists of four ‘planes’:1. Small, pinpoint pupils; the tidal breaths are large and regu-

lar; the pharyngeal and vomiting reflexes are depressed.2. Pupils are slightly larg