BASIC SCIENCE FOR ANAESTHETISTS This is a revised edition of a book originally titled Anaesthetic Data Interpretation. The new title better reflects the contents of the book, which contains additional chapters rel- evant to the Primary FRCA examination. New topics covered include the ventilatory response to oxygen and carbon dioxide, which is now a core knowledge requirement, new concepts in cardiovascular physiology, receptor types and the molecular actions of anaesthetics. Some of the revisions reflect advances in technology; for example, the uses of the capnograph and the oxygen analyser have advanced considerably in recent years. The aim is to provide a concise and understandable review of the physics, mathematics, statistics, physiology and pharmacology of anaesthesia. Basic Science for Anaesthetists is a concise and informative text, which will be invaluable for trainee anaesthetists and an aid to teaching for the trainers. S YLVA D OLENSKA qualified from Charles University, Prague, trained as an anaes- thetist in the UK and is currently Consultant Anaesthetist at William Harvey Hospital, Ashford, Kent. She has also acquired the KSS Deanery Certificate in Teaching. Her other key professional interests are airway management and obstetric anaesthesia. BASIC SCIENCE FOR ANAESTHETISTS BY SYLVA DOLENSKA MD LMSSA FRCA Consultant Anaesthetist, Department of Anaesthetics, The William Harvey Hospital, Ashford, Kent, UK CAMBRIDGE UNIVERSITY PRESS Cambridge, New York, Melbourne, Madrid, Cape Town, Singapore, São Paulo Cambridge University Press The Edinburgh Building, Cambridge CB2 8RU, UK First published in print format ISBN-13 978-0-521-67602-1 ISBN-13 978-0-511-16895-6 © 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 through research 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 provided by the manufacturer of any drugs or equipment that they plan to use. 2006 Information on this title: www.cambridge.org/9780521676021 This publication is in copyright. Subject to statutory exception and to the provision of relevant collective licensing agreements, no reproduction of any part may take place without the written p ermission of Cambrid g e University Press. ISBN-10 0-511-16895-0 ISBN-10 0-521-67602-9 Cambridge University Press has no responsibility for the persistence or accuracy of urls for external or third-party internet websites referred to in this publication, and does not g uarantee that any content on such websites is, or will remain, accurate or a pp ro p riate. Published in the United States of America by Cambridge University Press, New York www.cambridge.org paperback eBook (NetLibrary) eBook (NetLibrary) paperback To my husband CONTENTS List of abbreviations and symbols page xi List of figure captions xiii Forewords xvii Preface xxi Preface to the second edition xxiii Part 1: Physics, mathematics, statistics, anaesthetic apparatus 1 1. Gas compression, relationship of volume, pressure and temperature 2 2. Real gas compression 4 3. Flow and resistance 8 4. Heat, vaporization and humidification 14 5. Simple mechanics 1: mass, force, pressure 18 6. Simple mechanics 2: work and power 22 7. Mathematical concepts 26 8. Exponentials 1: the curves 30 9. Exponentials 2: properties of exponential decay curve 36 10. Descriptive statistics 40 11. Presentation of data 44 12. Receiver operating characteristic curve 48 13. Gas supply and pressure 52 14. The circle system 54 15. The Mapleson A (Magill) breathing system 58 16. T-pieces 60 17. Lung filling with automatic lung ventilators 62 Part 2: Clinical measurement 67 1. Basic measurement concepts 68 2. Electromanometers, frequency response and damping 72 3. Pulse oximeter principle 76 vii Contents 4. Oxygen content and oxygen tension measurement 80 5. Capnography 86 6. [H+], pH and its measurement 92 7. Principles of measurement of volume and flow in gases and liquids 96 8. Cardiac output measurement by thermal dilution technique 100 9. Measurement of the mechanical properties of the chest 102 10. Lung volumes and their measurement 104 Part 3a: Physiology: the cardiovascular system 109 1. The cardiac cycle and the intravascular pressure waveforms 110 2. Cardiovascular effects of intermittent positive pressure ventilation 114 3. Control of cardiac output, regulation of cardiac function 116 4. Cardiac cycle: pressure-volume relationships 118 5. Blood pressure and blood volume relationship 122 6. Cerebral blood flow 124 7. Coronary circulation 128 Part 3b: Physiology: the respiratory system 133 1. Oxyhaemoglobin dissociation curve 134 2. Respiratory mechanics 1: Static properties, factors affecting compliance, closing volume 136 3. Respiratory mechanics 2: Dynamic properties, factors affecting resistance 142 4. Ventilation–perfusion relationship 146 5. Oxygen cascade, oxygen therapy and shunt fraction 152 6. Gas R line, solution of the ventilation/perfusion model 156 7. Ventilatory response to oxygen 160 8. Ventilatory response to carbon dioxide 162 viii Contents Part 4: Pharmacology 165 1. Drug elimination 166 2. Uptake and distribution of inhalational anaesthetic agents 170 3. Pharmacodynamic effects of drugs 174 4. Minimum alveolar concentration and lipid solubility 180 5. Receptor types, molecular action of anaesthetics 182 6. Context sensitive half-time 186 Index 191 ix . pharmacology of anaesthesia. Basic Science for Anaesthetists is a concise and informative text, which will be invaluable for trainee anaesthetists and an aid to teaching for the trainers. S YLVA. Hospital, Ashford, Kent. She has also acquired the KSS Deanery Certificate in Teaching. Her other key professional interests are airway management and obstetric anaesthesia. BASIC SCIENCE FOR ANAESTHETISTS BY SYLVA. 189 xvi FOREWORD The syllabus for the Primary FRCA examination is broad, covering basic anaesthesia and associated skills together with an in depth knowledge of the principles of basic science