Veterinary Anaesthesia Veterinary Anaesthesia Principles to Practice Alex Dugdale, School of Veterinary Science, University of Liverpool A John Wiley & Sons, Ltd., Publication This edition fi rst published 2010 © 2010 by Blackwell Publishing Ltd Blackwell Publishing was acquired by John Wiley & Sons in February 2007. Blackwell’s publishing programme has been merged with Wiley’s global Scientifi c, Technical, and Medical business to form Wiley-Blackwell. Registered offi ce John Wiley & Sons Ltd, The Atrium, Southern Gate, Chichester, West Sussex, PO19 8SQ, United Kingdom Editorial offi ces 9600 Garsington Road, Oxford, OX4 2DQ, United Kingdom 2121 State Avenue, Ames, Iowa 50014-8300, USA For details of our global editorial offi ces, for customer services and for information about how to apply for permission to reuse the copyright material in this book please see our website at www.wiley.com/wiley-blackwell. 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This publication is designed to provide accurate and authoritative information in regard to the subject matter covered. It is sold on the understanding that the publisher is not engaged in rendering professional services. If professional advice or other expert assistance is required, the services of a competent professional should be sought. While the authors, editors, and publisher believe that drug selection and dosage and the specifi cation and usage of equipment and devices, as set forth in this book, are in accord with current recommendations and practice at the time of publication, they accept no legal responsibility for any errors or omissions, and make no warranty, express or implied, with respect to material contained herein. In view of ongoing research, equipment modifi cations, changes in governmental regulations and the constant fl ow of information relating to drug therapy, drug reactions, and the use of equipment and devices, the reader is urged to review and evaluate the information provided in the package insert or instructions for each drug, piece of equipment, or device for, among other things, any changes in the instructions or indication of dosage or usage and for added warnings and precautions. Library of Congress Cataloging-in-Publication Data Dugdale, Alex, 1966– Veterinary anaesthesia : principles to practice / Alex Dugdale. p. ; cm. Includes bibliographical references and index. ISBN 978-1-4051-9247-7 (pbk. : alk. paper) 1. Veterinary anesthesia–Handbooks, manuals, etc. I. Title. [DNLM: 1. Anesthesia–veterinary–Handbooks. SF 914 D866v 2010] SF914.D84 2010 636.089′796–dc22 A catalogue record for this book is available from the British Library. Set in 9.5/11.5 pt Minion by Toppan Best-set Premedia Limited Printed in Malaysia 1 2010 Contents Preface and Acknowledgements vii About the authors viii Chapter 1 Concepts of general anaesthesia 1 Chapter 2 Pre-operative assessment 4 Chapter 3 Pain 8 Chapter 4 Small animal sedation and premedication 30 Chapter 5 Injectable anaesthetic agents 45 Chapter 6 Quick reference guide to analgesic infusions 55 Chapter 7 Intravascular catheters: some considerations and complications 57 Chapter 8 Inhalation anaesthetic agents 64 Chapter 9 Anaesthetic breathing systems 76 Chapter 10 Anaesthetic machines, vaporisers and gas cylinders 93 Chapter 11 Anaesthetic machine checks 107 Chapter 12 Local anaesthetics 109 Chapter 13 Local anaesthetic techniques for the head: Small animals 118 Chapter 14 Local anaesthetic techniques for the limbs: Small animals 123 Chapter 15 Miscellaneous local anaesthetic techniques: Small animals 132 Chapter 16 Local anaesthetic techniques: Horses 135 Chapter 17 Muscle relaxants 141 Chapter 18 Monitoring animals under general anaesthesia 156 Chapter 19 Troubleshooting some of the problems encountered in anaesthetised patients 175 Chapter 20 Hypothermia: Consequences and prevention 179 Chapter 21 Blood gas analysis 182 Chapter 22 Lactate 192 Chapter 23 Fluid therapy 198 Chapter 24 Electrolytes 216 Chapter 25 Drugs affecting the cardiovascular system 225 Chapter 26 Shock 232 Chapter 27 Gastric dilation/volvulus (GDV) 244 Chapter 28 Equine sedation and premedication 247 v vi Contents Chapter 29 Equine heart murmurs 259 Chapter 30 Equine anaesthesia 260 Chapter 31 Equine intravenous anaesthesia in the fi eld and standing chemical restraint 274 Chapter 32 Donkeys 277 Chapter 33 Ruminants: Local and general anaesthesia 279 Chapter 34 Lamoids (formerly South American camelids) (llamas, alpacas, guanacos and vicunas) 299 Chapter 35 Pigs: Sedation and anaesthesia 302 Chapter 36 Rabbit anaesthesia 309 Chapter 37 Neonates/paediatrics 312 Chapter 38 Geriatrics 315 Chapter 39 Pregnancy and Caesarean sections 318 Chapter 40 Considerations for ocular surgery 322 Chapter 41 Orthopaedic concerns 325 Chapter 42 Renal considerations 327 Chapter 43 Hepatic considerations 330 Chapter 44 Some endocrine considerations 333 Chapter 45 Background to neuroanaesthesia for the brain 337 Chapter 46 Some cardiac considerations 341 Chapter 47 Some respiratory considerations 344 Chapter 48 Respiratory emergencies 347 Chapter 49 Cardiopulmonary cerebral resuscitation (CPCR) 359 Appendix 1 Canine emergency drug dose chart 366 Appendix 2 Feline emergency drug dose chart 368 Appendix 3 Equine emergency drug dose chart 370 Answers to self-test questions 371 Index 376 Tear out and keep: Accidents and emergencies procedure list Chapter titles in bold italics represent ‘Information only’ chapters. Preface and Acknowledgements without a little pride, that wells up inside when past students go Preface on to achieve great things and especially when they keep in touch Welcome to ‘ Veterinary Anaesthesia: Principles to Practice ’ . by email with all manner of taxing questions which really keep me T he book was developed from The Liverpool University on my toes! Learning and teaching will always be a two- w ay Veterinary School student notes after much encouragement process and I can only hope to impart some of my experiences from both undergraduate and postgraduate students and is now fl avoured with a little of my enthusiasm through the pages of this envisaged as a basic study aid for veterinary nurses, veterinary book, but am always open to discussion so please do contact me students and particularly post - graduate students studying for if you feel the urge! professional veterinary anaesthesia qualifi cations. The book is I hope that you too can develop a passion and enthusiasm also designed to be a quick - reference source for veterinary for anaesthesia and a deep enjoyment of being able to witness surgeons in practice. physiology and pharmacology interact at your fi ngertips. D uring my fi rst ever dog anaesthetic in practice, on a busy Happy reading! morning when all my colleagues were out on calls, the responsibil- ity of the situation suddenly dawned on me when I realised just Acknowledgements how many questions I still had about the subject. Fortunately, a quick call via a temperamental mobile telephone helped to assure My grateful thanks are extended to my contributors: Nicki Grint me that my calculations of premedication and induction doses for the Rabbit Anaesthesia chapter and photographs and Mark were reasonable and thankfully my patient survived. That after- Senior for sowing the seeds of the chapters on Pain, Monitoring, noon, however, I telephoned the RCVS to enrol for the CertVA Fluid Therapy and Equine Anaesthesia. as I had clearly realised just how much more I needed to learn. I would also like to extend my gratitude to all past and present And I have been learning ever since, sometimes by my mistakes, students and colleagues from Liverpool ’ s Veterinary School and but hopefully more often through the guidance and instruction our many visiting residents for their encouragement. In particu- of others, notably Dr. Jackie Brearley and Prof. Ron Jones, and lar, however, I owe much to Claire Dixon for her unfaltering from the written word. My colleagues will attest to my passion for support and technical wizardry with word - processing. books – I only wish I had time to read them all! So why, might F inally, without the amazing support of Amy, Justinia and Katy you ask, would I wish to write one? Well, I really enjoy teaching at Wiley - Blackwell, this book would not have been published. as well as learning. There is a wonderful sense of satisfaction, not My debt to them is more than words could ever say. vii About the authors Principal Author: Alexandra Helena Anne Dugdale MA, VetMB, Contributor: Nicola Jane Grint BVSc, Dip.ECVAA, DVA, CPS, DVA, Dip.ECVAA, PGCert(LTHE), FHEA, MRCVS, RCVS MRCVS. Recognised Specialist in Veterinary Anaesthesia, European Nicki qualifi ed from Bristol Veterinary School in 2000 and com- Specialist in Veterinary Anaesthesia. pleted an Internship and then a Residency in Veterinary Anaesthesia at Bristol before joining the veterinary anaesthesia Alex qualifi ed from Cambridge University Veterinary School in team at Liverpool Veterinary School in 2005 as Lecturer in 1990 after which she spent 6 years in mixed practice in Lancashire. Veterinary Anaesthesia. Nicki gained the CertVA in 2002, the Dip. She gained the RCVS Certifi cate in Veterinary Anaesthesia and a ECVAA in 2005 and the DVA in 2006, shortly followed by a pro- private pilot ’ s licence in 1993 (who said anaesthesia was like fessional teaching qualifi cation (Certifi cate in Professional fl ying!) and then undertook a Residency in Anaesthesia and Studies) in 2007. She is currently undertaking a PhD at the Critical Care at the Animal Health Trust in Newmarket between University of Bristol in the fi eld of donkey analgesia. 1996 and 1999 under the supervision of Dr. Jackie Brearley. She was appointed Temporary Lecturer in Veterinary Anaesthesia at Contributor: Jonathan Mark Senior BVSc, CertVA, Dip.ECVAA, Liverpool University in 1999 and gained the Diplomas of both the PhD, MRCVS RCVS and ECVAA in 2001 before becoming Lecturer and later Mark qualifi ed from Liverpool University Veterinary School in Senior Lecturer in Veterinary Anaesthesia. She became Head of a 1997, spending two years in mixed practice in Yorkshire before newly created Division of Veterinary Anaesthesia in 2004 and returning to Liverpool University as a Resident in Veterinary completed a postgraduate qualifi cation in teaching in 2006. She Anaesthesia under the supervision of Prof. Ron Jones. He gained is currently on sabbatical to undertake a PhD in equine obesity. his CertVA in 2000 and the Dip.ECVAA in 2004, becoming Lecturer in Veterinary Anaesthesia in 2002. He gained his Doctorate in 2008 for his thesis on ‘ Complement and Endotoxin in Equine Colic ’ . viii