New Book: Your Guide to Paediatric Anaesthesia, Craig Sims & Chris Johnson

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Be just as confident managing children as adults! This book will give students and clinicians the knowledge and practical information you need to get the most out of your precious paediatric training time. The first Australian text on the subject of paediatric anaesthesia, this book is written in a readable and practical style and provides practitioners and students with the practical clinical skills and techniques to care for children.

More info: http://www.mcgraw-hill.com.au/html/9780071000222.html

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New Book: Your Guide to Paediatric Anaesthesia, Craig Sims & Chris Johnson

  1. 1. YOUR GUIDE TO PAEDIATRICANAESTHESIA CRAIG SIMS & CHRIS JOHNSON ly on s ge pa e pl m sa
  2. 2. YOUR GUIDE TO PAEDIATRICANAESTHESIA ly on s ge pa e pl m sa
  3. 3. DEDICATIONTo those who have taught us so well ly on s ge pa e pl m sa
  4. 4. YOUR GUIDE TO PAEDIATRICANAESTHESIA CRAIG SIMS & CHRIS JOHNSON ly on s ge pa e pl m sa
  5. 5. NoticeMedicine is an ever-changing science. As new research and clinical experience broaden our knowledge, changes in treatment and drug therapy arerequired. The editors and the publisher of this work have checked with sources believed to be reliable in their efforts to provide information that iscomplete and generally in accord with the standards accepted at the time of publication. However, in view of the possibility of human error or changesin medical sciences, neither the editors, nor the publisher, nor any other party who has been involved in the preparation or publication of this work war-rants that the information contained herein is in every respect accurate or complete. Readers are encouraged to confirm the information contained hereinwith other sources. For example, and in particular, readers are advised to check the product information sheet included in the package of each drug theyplan to administer to be certain that the information contained in this book is accurate and that changes have not been made in the recommended doseor in the contraindications for administration. This recommendation is of particular importance in connection with new or infrequently used drugs.Copyright © 2011 McGraw-Hill Australia Pty LimitedAdditional owners of copyright are acknowledged in on-page credits.Every effort has been made to trace and acknowledge copyrighted material. The authors and publishers tender their apologies should any infringementhave occurred.Reproduction and communication for educational purposesThe Australian Copyright Act 1968 (the Act) allows a maximum of one chapter or 10% of the pages of this work, whichever is the greater, to be repro-duced and/or communicated by any educational institution for its educational purposes provided that the institution (or the body that administers it)has sent a Statutory Educational notice to Copyright Agency Limited (CAL) and been granted a licence. For details of statutory educational and othercopyright licences contact: Copyright Agency Limited, Level 15, 233 Castlereagh Street, Sydney NSW 2000. Telephone: (02) 9394 7600. Website:www.copyright.com.au lyReproduction and communication for other purposesApart from any fair dealing for the purposes of study, research, criticism or review, as permitted under the Act, no part of this publication may beMcGraw-Hill Australia including, but not limited to, any network or other electronic storage. onreproduced, distributed or transmitted in any form or by any means, or stored in a database or retrieval system, without the written permission ofEnquiries should be made to the publisher via www.mcgraw-hill.com.au or marked for the attention of the permissions editor at the address below. sNational Library of Australia Cataloguing-in-Publication Data geTitle: Your guide to paediatric anaesthesia / Craig Sims, Chris Johnson, editors.ISBN: 9780071000222 (pbk.) paSubjects: Pediatric anesthesia—Handbooks, manuals, etc Children—Surgery—Care—Handbooks, manuals, etc. Pediatric anesthesia—Examinations—Study guides.Other Authors/Contributors: Sims, Craig. Johnson, Chris. eDewey Number: 617.96 plMcGraw-Hill Australia Pty LtdLevel 2, 82 Waterloo Road, North Ryde NSW 2113Acquisitions editor: Fiona Richardson mCover and internal design: Alicia FreileProduction editor: Laura Carmody, Jess Ní Chuinn saCopyeditor: Laura DaviesIllustrations: LaserwordsProofreader: Jill PopeIndexer: Glenda BrowneTypeset in Minion Pro Regular 10/14 pt by Laserwords, IndiaPrinted in China on 80gsm matt art by CTPS
  6. 6. vC O NTE NTS Contributors vii Preface viii Twelve current issues ix Useful formulae for paediatric anaesthesia xi Abbreviations used in the text xiii 1 An overview of paediatric anaesthesia 1 2 Pharmacology of anaesthetic agents in children 20 3 Behavioural management of children 40 4 Airway management 55 5 Fluid management 83 6 Equipment and monitoring 97 ly 7 Resuscitation and emergency drugs 114 8 Acute pain management on 131 s 9 ge Regional anaesthesia 15010 Respiratory illnesses and their influence on anaesthesia 165 pa11 Chronic diseases of childhood 179 e12 pl Congenital syndromes & conditions 19513 m Neonatal anaesthesia 201 sa14 Anaesthesia for paediatric general surgery 224
  7. 7. vi YO U R G U I D E T O PA E D I AT R I C A N A E S T H E S I A15 Anaesthesia for ENT surgery 23816 Bronchoscopy & removal of foreign bodies from the trachea 25017 Anaesthesia for dental procedures 26018 Orthopaedic surgery 26519 Congenital heart disease 27120 Anaesthesia for thoracic surgery 28421 Anaesthesia for plastic surgery 29022 Paediatric neuroanaesthesia 29623 Anaesthesia for ophthalmic surgery 30324 Anaesthesia for urological surgery 30725 Trauma and burns 313 ly26 Malignancy and treatment of malignancies 32627 on Procedural sedation: anaesthesia & sedation of children away from the OR 334 s28 Vascular access 342 ge29 The child at risk—child protection and the anaesthetist 350 pa30 Paediatric intensive care 354 e31 Glossary of syndromes and diseases 364 pl m Short-answer questions from past FANZCA and FRCA examinations 369 Index 375 sa
  8. 8. E D I TO R S A N D C O N T R I B U TO R S viiE D ITO R SDr Craig Sims MBBS, FANZCAPaediatric AnaesthetistPrincess Margaret Hospital for ChildrenPerth, Western AustraliaDr Chris Johnson MBBS, FANZCADirector, Surgical ServicesPaediatric AnaesthetistPrincess Margaret Hospital for ChildrenPerth, Western AustraliaC O NTR I B UTO R SFrom the Department of Anaesthesia and Pain Management, Princess Margaret Hospital for Children. Perth,Western Australia:Dr Ric Bergesio* MBBS, FANZCADr Alison Carlyle* MBChB, FRCA, FANZCADr Neil Chambers* MBBS, FRCA, FANZCADr Elaine Christiansen* MBBS, FANZCADr Tanya Farrell* MBBS, FANZCA, MBADr Ian Forsyth* BSc (Hons), MBChB, FANZCADr Mairead Heaney* MB BCh Dch FCARCSI FCICM FANZCA lyDr Mary Hegarty* BSc, MBBS, FRCA, FANZCADr Bruce Hullett* MBBS, FANZCADr Charlotte Jorgensen* MBBS, FANZCADr Serge Kaplanian* MBBS, FRACGP, FANZCA on sDr Lisa Khoo* MBBS, FANZCADr Soo Im Lim* MBBS, FANZCA geDr Tessa Meyer* MBBS, FRCA, FANZCAProf Britta von Ungern-Sternberg** MD, PhD, DEAA, FANZCA paDr Claudia Rebmann* MD, FRCA, FANZCADr Phil Russell* MBBS(Hons), FANZCADr Prani Shrivastava* MBBS, FANZCA eDr Priya Thalayasingam* AM, MBBS, FANZCA plDr John Thompson* MBBS, FANZCAFrom the Paediatric Intensive Care Unit, Princess Margaret Hospital for Children. Perth, Western Australia: mDr Daniel Alexander*** MBBS, FRACP, FJFICM sa* Paediatric Anaesthetist** Chair of Paediatric Anaesthesia, The University of Western Australia and Princess Margaret Hospital forChildren, Perth, Western Australia*** Paediatric Intensivist
  9. 9. v iii YO U R G U I D E T O PA E D I AT R I C A N A E S T H E S I AP R E FA C EWhy are so many anaesthetists nervous at the thought of looking after children? Two reasons: firstly, it is themanagement of the child’s small airway—everyone knows that children go blue very fast! Secondly, it is themanagement of childhood behaviour and anxiety, often transmitted from parents. Children let everyone know ifthey’re scared or in pain. The key to paediatric anaesthesia is to learn the skills to be confident about managing a child’s airway. Onceyou have mastered this you can relax into anaesthetising children, start to enjoy working with them and theirparents and learn the art of managing anxiety in parents and their children. This book will give you the knowledge and practical information you need to get the most out of your preciouspaediatric training time so that you can become as confident managing children as you are with adults. This isthe one book that gives both all the information you need to prepare for specialist exams, and the knowledge ofcontemporary paediatric anaesthesia that will stand you in good stead as a consultant anaesthetist. This bookassumes prior knowledge about anaesthesia in adults and concentrates on fully explaining what is different aboutchildren. The editors and chief authors are both clinical, full-time paediatric anaesthetists in the public and privatehealth systems, anaesthetising about 2000 children each year between them. The authors are all experienced,clinical paediatric anaesthetists. Some may see it as a limitation that they are all from one hospital. Your authors,however, are all well-studied and trained, and give you the experience gained in 17 leading paediatric institutionsin eight countries across the UK, Europe, North America and South Africa as well as Australia and New Zealand.Many ‘multinational, multi-author’ texts only give you the views of one author from one institution in eachchapter. We have been careful that our work reflects contemporary Western practice and is not merely theapproach from a single institution. Although we have discussed a range of approaches for each clinical problem, lywe have been careful to highlight a safe and pragmatic approach for the reader based on the authors’ extensiveclinical experience. on We hope that you enjoy reading this book and learn much from it. We would encourage reader feedbackon ideas for future topics, and most of all, hope that it aids you to become more relaxed and comfortableanaesthetising children. s ge Craig Sims and Chris Johnson pa e pl m sa
  10. 10. T W E LV E C U R R E N T I S S U E S I N PA E D I AT R I C A N A E S T H E S I A ixT W E LV E C U R R E N T I S S U E S I N PA E D I ATR I C A N A E STH E S I A,AN D W H E R E TO FI N D TH E M1. Emergence deliriumYoung children sometimes wake from anaesthesia crying and unhappy. There are many reasons for this, althoughsevoflurane dysphoria is commonly blamed. See Chapter 1, ‘An overview of paediatric anaesthesia’, page 12.2. Dextrose in IV fluids for childrenHypotonic, dextrose-containing solutions have been traditionally used for IV fluids in children. The risk ofhyponatraemia from these fluids is so high that salt-rich fluids are recommended nowadays. See Chapter 5, ‘Fluidmanagement’, page 88.3. The uncooperative childMany do not like anaesthetising children because of difficulty with the child’s behaviour at induction. SeeChapter 3, ‘Behavioural management of children’.4. The airwayMany anaesthetists do not like caring for children because of difficulty managing their airway. See Chapter 4,‘Airway management’, for many practical tips.5. Cuffed endotracheal tubesUncuffed endotracheal tubes have traditionally been used in children. It is now realised that cuffed ETTs offer lymany advantages. See Chapter 4, ‘Airway management’, page 69.6. Neurotoxicity of anaesthetic agents onThere is laboratory evidence that many anaesthetic agents, including volatiles, affect the developing brain of sneonates. See Chapter 2, ‘The pharmacology of anaesthetic agents in children’, page 29. ge7. Intubation without relaxantsMuscle relaxants are being used less and less in children as it is realised that satisfactory intubating conditions can pabe achieved without them. See Chapter 4, ‘Airway management’, page 72.8. Dexamethasone in tonsillectomy eDexamethasone is commonly used in tonsillectomy to reduce pain and vomiting and to shorten the time to ploral intake. There is some evidence that high-dose dexamethasone increases bleeding after tonsillectomy. SeeChapter 15, ‘Anaesthesia for ENT surgery’, page 244. m9. Child abuse saMore and more legislatures are passing laws that make it mandatory for all involved in the care of children toreport any suspicion of child abuse. See Chapter 29, ‘The child at risk: child protection and the anaesthetist’.
  11. 11. x YO U R G U I D E T O PA E D I AT R I C A N A E S T H E S I A10. Reducing pain and distress during proceduresHolding a child down to perform a procedure is becoming less and less acceptable. Many techniques and drugsare now used to make procedures more comfortable and less distressing for the child, parents and staff. SeeChapter 27, ‘Procedural sedation: anaesthesia and sedation of children away from the operating room’.11. Managing the critically ill child before transfer to a paediatric centreThere are several recurrent issues that may require attention when a child is transferred from a peripheral hospital.See Chapter 30, ‘Paediatric intensive care’, page 356.12. Laparoscopic surgeryMore and more laparoscopic surgery is being performed in neonates and infants. See Chapter 14, ‘Anaesthesia forpaediatric general surgery’, page 226. ly on s ge pa e pl m sa
  12. 12. USE FU L FOR M U LAE xiU S E F U L F O R M U L A E F O R PA E D I ATR I C A N A E STH E S I AWeightBody weight for infants 5 (age in months 1 9) / 2Body weight for children 1–10 y 5 (age 1 4) 3 2Body weight for children older than 10 y 5 age 3 3 (large variation in normal adolescent weight, however)Blood pressureExpected systolic blood pressure for children older than 1 y 5 80 1 (age in years 3 2) mmHgFluidsMaintenance fluid rate in mL/h: (4:2:1 rule)4 mL/kg first 10 kg weight 1 2 mL/kg next 10 kg weight 1 1 mL/kg for rest of weight(e.g. for 19 kg child: (10 3 4) 1 (9 3 2 ) 5 58 mL/h)Minimum 10% dextrose infusion for neonate day one (4 mg/kg/min) in mL/h 5 2.5 3 weight in kg(e.g. 3 kg neonate needs at least 7.5 mL/h 10% dextrose)Blood transfusionBlood volume of child 5 (70 3 weight in kg) mLBlood volume of infant 5 (80 3 weight in kg) mL10 mL/kg of packed cells increases the Hb by 3 g/dL; or 4 mL/kg of packed cells increases the Hb by 1 g/dL ly initial Hb 2 final HbAllowable blood loss 5 __________________ 3 blood volume intial HbETT sizeUncuffed ETT size for child over 2 y: (Age / 4) 1 4 5 ETT size (inside diameter, mm) on sCuffed ETT size for child over 2 y: (Age / 4) 1 3.5 5 ETT size (ID, mm) geETT lengthPosition at vocal cords 5 ID size of ETT (e.g. 4.5 ETT should be 4.5 cm at vocal cords) paOral ETT length (at lips in cm) 5 (Age / 2) 1 12Nasal ETT length (at nostril in cm) 5 (Age / 2) 1 15 (and diameter of correct-size nasal ETT same as oral ETTfor children) eNeonates: oral ETT length (at lips in cm) 5 weight (kg) 1 6 plNeonates: nasal ETT length (at nares in cm) 5 (weight (kg) 3 1.5) 1 7 m sa
  13. 13. xii YO U R G U I D E T O PA E D I AT R I C A N A E S T H E S I ASuction catheter for ETTSize of suction catheter for ETT (in French Gauge) 5 2 3 size of ETT (ID)Urinary catheterUrinary catheter size (FG) 5 2 3 size of ETT (ID)CVCDepth for CVC placement in right IJV 5 10% of height(e.g. 8 cm in an 80 cm child) ly on s ge pa e pl m sa
  14. 14. A B B R E V I AT I O N S xiiiA B B R E V I AT I O N S U S E D I N TH E TE X TAbbreviation Meaning Abbreviation MeaningABG arterial blood gas ETT endotracheal tubeADH anti-diuretic hormone EUA examination under anaesthesiaALL acute lymphoblastic leukaemia EVD external-ventricular drainAPL adjustable pressure limiting FANZCA Fellowship of the Australian and NewAPS acute pain service Zealand College of AnaesthetistsARDS acute respiratory distress syndrome FEV forced expiratory volumeASD atrial septal defect FRC functional residual capacityAVSD atrioventricular septal defect FRCA Fellowship of the Royal College ofAXR abdominal X-ray AnaesthetistsBAL broncho-alveolar lavage GCS Glasgow Coma ScoreBHR bronchial hyperreactivity GFR glomerular filtration rateBMI body mass index GIT gastrointestinal systemBMR basal metabolic rate HbA adult haemoglobinBP blood pressure HbF foetal haemoglobinbpm beats per minute HDU high dependency unitBSA body surface area HDU/ICU high dependency unit/intensive careBSL blood sugar level unitCBF cerebral blood flow HFOV high frequency oscillatory ventilation lyCDH congenital diaphragmatic hernia HLHS hypoplastic left heart syndromeCNS central nervous system HMD hyaline membrane diseaseCPPCPR cerebral perfusion pressure cardiopulmonary resuscitation IAP ICF on intra-abdominal pressure intracellular fluid volumeCSF cerebrospinal fluid ICU intensive care unit sCVC central venous catheter IJV internal jugular vein geCVP central venous pressure IOP intraocular pressureCXR chest X-ray IPPV intermittent positive pressureDIC disseminated intravascular ventilation pa coagulation IVC inferior vena cavaDLT double-lumen tube LMA laryngeal mask airwayDORV double-outlet right ventricle LTA laryngeal tube airway eDRG dorsal root ganglion LV left ventricle plDVT deep vein thrombosis MAC minimum alveolar concentration mECF extracellular fluid volume MAP mean arterial pressureECG electrocardiogram MDI metered dose inhaler saECMO extracorporeal membrane MPS mucopolysaccharidoses oxygenation MV minute ventilationEEG electroencephalogram NAI non-accidental injuryENT ear nose and throat NEC necrotising enterocolitis
  15. 15. xiv YO U R G U I D E T O PA E D I AT R I C A N A E S T H E S I ANGT nasogastric tube RDI respiratory disturbance indexNMBD neuromuscular blocking drugs RDS respiratory distress syndromeNRS numerical rating scale ROP retinopathy of prematurityOLV one-lung ventilation RR respiratory rateOME otitis media with effusion RSV respiratory syncytial virusOR operating room RV right ventricleOSA obstructive sleep apnoea SVC superior vena cavaOSD obstructive sleep disorder SVR systemic vascular resistancePACU post-anaesthesia care unit TBI traumatic brain injuryPAT pain assessment tool TBW total body waterPCA postconceptual age TCI targe controlled infusionPDA patent ductus arteriosus TENS transcutaneous electrical nervePEA pulseless electrical activity stimulatorPEEP positive end expiratory pressure TOF tracheo-oesophageal fistula/tetralogyPICC peripherally inserted central venous of Fallot catheter VAS visual analogue scalePICU paediatric intensive care unit VFT ventilatory function testPVR pulmonary vascular resistance VSD ventricular septal defectRBC red blood cellA note on the textTerms from the ‘Glossary of syndromes and diseases’ (page 364) appear in bold when first used in thechapter text. ly on s ge pa e pl m sa
  16. 16. C HA P T E R 1AN OVERVIEW OFP A E D I ATR I C A N A E S T H E S I ACraig Sims and Tanya FarrellT he terms ‘paediatric’ and ‘child’ apply to someone aged less than 18 years. The American Academy of Pediatrics defines ‘pediatric’ as less than 21 years, whilesome centres use 16 years. An ‘infant’ is a child aged between one and 12 months; ly‘neonate’ applies to the first four weeks after birth. Children make up a quarter of the population in most Western countries on lyand a higher proportion in developing countries. Paediatric anaesthesia is very scommon—5.5% of children have an anaesthetic each year. The commonest indication on gefor anaesthesia is ENT surgery, but children often need anaesthesia for procedures s pasuch as scans and dental treatment that an adult would tolerate without anaesthesia. ge eSafety of paediatric anaesthesia pa plAnaesthesia for children has become very safe. Parents can be reassured that the profession has taken many steps m eover the years to reduce risk. These steps include analysing past incidents (anaesthesia was the first specialty to pl saperform incident monitoring), embracing new monitoring technologies, improving specialist training and takingadvantage of safer drugs. The overall mortality from anaesthesia alone in a healthy child is approximately 1 in m50 000 to 1 in 100 000. sa
  17. 17. 2 YO U R G U I D E T O PA E D I AT R I C A N A E S T H E S I A Morbidity is common with anaesthesia in children. The incidence is higher at young ages—children aged3 years and younger have a higher risk than older children. Infants are particularly at risk, with critical incidentsfour times more likely in this age group compared to older children. Young children are at greater risk due totheir small airway diameter, predisposition to develop apnoea or airway obstruction from airway irritation, andpredisposition to rapid desaturation. The risk of morbidity is lower if the anaesthetist is experienced and has a large paediatric case load. Althoughthere are no formal requirements for anaesthetists caring for children, it is generally agreed that practitionersanaesthetising children aged 3 years and younger should regularly anaesthetise this age group, and anaesthetistscaring for children aged less than 1 year should regularly anaesthetise infants. Neonatal anaesthesia should beperformed by those who have a fellowship in paediatric anaesthesia. KEY POINT Children aged less than 3 years, and especially aged less than 1 year, are at a higher risk from anaesthesia than older children.Organisation of servicesIf you are anaesthetising a child in a non-paediatric hospital, it is important to ensure that it is safe to do so.The professional colleges and societies issue guidelines for anaesthetists caring for children. These outline thestaffing requirements and the types of equipment and facilities needed. In addition, there are guidelines from theprofessional bodies responsible for nurses, surgeons, medical specialties and hospitals that are directed at theirfellows and members. ly Several factors determine if a child can be safely cared for at a particular facility. Broadly, there are factorsrelating to the patient and the type of surgery planned (see Table 1.1), and factors relating to the hospital, such as the onlevel of staffing, equipment and facilities (see Table 1.2). An older child undergoing day surgery has different healthfacility requirements to an infant with coexisting medical problems requiring overnight admission after surgery. ly The Australian and New Zealand College (ANZCA) guideline PS29 (2008) and the United Kingdom College s on(RCOA) guidelines discuss staffing for the care of children in non-paediatric hospitals. These policies particularly ge sTable 1.1 Patient factors to consider in determining level of staff and facilities needed to safely care for pa ge children e Patient factor pa pl Age of child, especially if , 12 months m Type of surgery e ASA status/general health of child pl sa Overnight admission m Emergency procedure sa
  18. 18. CHAPTE R 1 A N O V E R V I E W O F PA E D I AT R I C A N A E S T H E S I A 3Table 1.2 Summary of requirements to safely anaesthetise children Organisation of services Staff Experience and case load to maintain competency in relevant ages and case mix of: Anaesthetist Assistant Recovery  Ward nurses Equipment In addition to equipment and facilities needed to safely anaesthetise adult patients: Size-appropriate breathing circuit, airway equipment and monitoring Anaesthetic machine and ventilator suitable for ages of children being anaesthetised Suitable fluid administration devices (may include burette) Resuscitation drugs and equipment (including defibrillator and pads suitable for children) Ability to control temperature of OR Beds and cots suitable to contain child and prevent falls Facilities Ability for parents to accompany child to theatre and be present in recovery Separated areas from adults—wards, OR, PACU Accommodation for parents if overnight admission Links to tertiary paediatric centres for advice and transfer of patients if postoperative problems Pharmacy knowledgeable in paediatric doses Acute pain service, HDU/ICU if relevant to case mix lyAdapted from ANZCA PS29 and RCOA guidelines. onapply to infants and neonates because of their greater risk. Anaesthetists looking after children should have lytraining in the relevant age group, and should not anaesthetise children if they are not comfortable to do sofrom either lack of recent experience or inadequate case load. Having a second anaesthetist to help should be s onconsidered for infants and children ASA3 status or higher, and the anaesthetic assistant and perioperative staff geshould have training in the care of children. Finally, it should be possible to obtain advice from an establishedspecialist paediatric facility should it be required. The more detailed UK guidelines recommend a lead consultant s pato oversee provision of paediatric anaesthetic services. gePreoperative assessment e pa plJust as with adults, assessment of children before anaesthesia includes a history and examination that aim to m eassess previous anaesthetic problems and the severity of co-existing diseases. It is also an opportunity to establish plrapport with the child and parents, assess the child’s behaviour and reassure the parents with your manner and saprofessionalism. Most children are healthy and active, although there is always the possibility of an unrecognised mabnormality or syndrome. Some children have dysmorphic features suggesting an underlying syndrome (seeTable 1.3 overleaf). If a child has one congenital malformation it is more likely that there will be another. Common sa
  19. 19. 4 YO U R G U I D E T O PA E D I AT R I C A N A E S T H E S I Aconditions to specifically ask about include preterm delivery, recent upper respiratory tract infection andobstructive sleep disorder. Examination needs to take into consideration the modesty of the child, particularly with school-aged childrenand adolescents. Weight, temperature, heart rate and oxygen saturation are routinely measured. Examinationmay occasionally reveal a previously unrecognised heart murmur (see Chapter 19), signs of asthma or URTI(see Chapter 10) or loose teeth. The most important aspect of airway assessment is mandibular size (seeChapter 4). Investigations such as haemoglobin, chest X-ray (CXR) and urinalysis are not routinely performedin healthy children undergoing minor surgery. Haemoglobin is not tested because significant anaemia is rarein children and mild anaemia does not affect the decision to proceed with anaesthesia. Some centres use theSickledex test in patients at risk of sickle cell anaemia.Table 1.3 Facial dysmorphic features that may indicate a congenital syndrome Dysmorphic feature Widely spaced eyes (hypertelorism) Beaked or other nose abnormality Low hairline on forehead Low-slung or malformed ears Craniosynostosis Microcephaly Pre-anaesthetic clinics are not always used for healthy children. Clinics are unlikely to reveal significant lymedical problems, are inconvenient for the family, and the most likely reason for cancellation of surgery is a viralillness just before surgery. Assessment is commonly made by a telephone interview before admission and reviewby the anaesthetist on the day of surgery. on lyLoose teeth sChildren lose deciduous teeth from 5 years of age. A very loose tooth may dislodge and be aspirated during on geanaesthesia and is sometimes removed (with parental permission) after induction. The tooth needs to be veryloose before trying this, and usually has no visible root (it is resorbed). If the tooth is not very loose it can be s pasurprisingly difficult and unpleasant to remove, and the gum may bleed. A tooth that is not on the verge of falling geout can be watched carefully during airway manipulation to avoid dislodgement and checked at the end of thecase to make sure it has not been dislodged. e pa plConsent m e pl saThe legal age for consent is usually between 16 and 18 years, depending on the jurisdiction. Consent for childrenis therefore obtained from the parent or legal guardian. There is growing recognition, however, of the rights of myounger people. It is usual to at least obtain the assent (permission) to proceed with anaesthesia and surgery in sa
  20. 20. CHAPTE R 1 A N O V E R V I E W O F PA E D I AT R I C A N A E S T H E S I A 5older school-aged children, even though they may not be able to give legal consent. Further complicating this areais the increasing recognition by courts of children’s ability to make their own decisions about treatment. Somehealth areas have policies in place that allow children as young as 14 years to consent to treatment. However, thesepolicies are not a replacement for laws and it is still usual to obtain parental consent when the child is youngerthan 16–18 years. The Gillick competency test establishes the legal principles to decide a child’s ability to make healthcaredecisions. The Gillick test forms part of common law in Australia, and it arose from a case about whetheror not a parent’s permission was required for prescription of the oral contraceptive to a 16-year-old girl. Thefindings of this case have been used to determine consent issues in general. For a child to be deemed competentto decide about their health care, they must have the ability to understand the factual, moral and emotionalconsequences of their decision. Competence is not reliant on a fixed age, and competence for one situation doesnot imply competence for all. The child’s age is still considered—the younger the child, the less likely the child canunderstand the implications of their decision. KEY POINT Although some adolescents are mature enough to consent to anaesthesia and surgery, it is wise to obtain a parent’s consent. In certain life-threatening circumstances, society allows the wishes of a child or the parents to be overridden.This is firstly because a child is unlikely to competently rationalise life and death decisions, especially whenthey are so easily influenced by authority figures. Secondly, society is unwilling to allow any person to make lifeand death decisions for someone else, including one’s own child. Hence laws make it possible in an emergencyto override the wishes of a person aged less than 18 years. The exact legal mechanisms for this vary betweenjurisdictions, and the involvement of the hospital’s medical administrator is usual. These emergency provisions lyonly apply if the procedure is critical and life saving—a blood transfusion in severe hypovolaemic shock may onbe permitted, but not force-feeding an anorexic child who is not critically ill. As a practical matter, it is best tonegotiate a compromise before proceeding to the courts for permission. Consent to treatment is more likely to be lygiven when the child’s and parents’ wishes and concerns are considered. s Fortunately for paediatric anaesthetists, consent issues are usually resolved by the time a child presents for on gesurgery. However, consent issues for anaesthetists may arise at the time of induction—is it reasonable to proceedwhen the child withdraws their hand from the IV cannula, or pushes away the face mask? Children older thanabout 8–10 years who are developmentally normal probably should not be restrained. Fear is often a large part of s pathe child’s refusal, and this can be allayed with discussion, parental involvement, involvement of play therapists gein children having many anaesthetics, and pharmacological premedication if agreed. Younger children areprobably not able to understand the importance of their treatment and it may be reasonable to restrain the child e paand proceed if other strategies fail. Supervising the parent to help restrain a younger child can help parents to placcept this course of action. Although restraining a 2 or 3-year-old child is straightforward and not uncommon,restraining a young school-aged child is unpleasant for the child, parent and staff, and should be avoided as m emuch as possible by paying attention to the behavioural management aspects of the child. The age beyond which plrestraint is not reasonable depends on many surgical, patient, practical, societal and reality factors. A great deal saof judgement is involved from case to case. Sometimes during induction a decision must be made quickly to take mone path or another before the child’s cooperation deteriorates further. sa
  21. 21. 6 YO U R G U I D E T O PA E D I AT R I C A N A E S T H E S I ABlood transfusion in a Jehovah’s Witness childA blood transfusion critical to survival of the child (usually as determined by more than one doctor) can begiven legally without the consent of the parents. In fact, doctors have a legal obligation not to allow a child todie by withholding treatment. In the elective situation, children older than 14–16 years may be able to refuse atransfusion themselves, but the legality of this would need to be determined before proceeding with surgery. When the child’s parents refuse permission for a blood transfusion, they are usually only trying to do what isbest for their child. Indeed, anaesthetists should be trying to minimise blood transfusion in every child—there aremany risks of transfusion, and children have a long life ahead for these risks to become apparent. Confrontation over this issue can be minimised by listening to the parents, telling them all the things that youwill do to try to avoid blood products, and telling them that you are legally obliged not to let their child die. Thereis no need to force parents to explicitly agree with this plan and thus refute their own beliefs. There is also little tobe gained from a confrontation with parents who are under stress about their child’s anaesthesia and surgery whenthe likelihood of transfusion is extremely low. As medical providers, the legal obligation is straightforward andmost parents are aware of these legal obligations. Ongoing argument serves only to put parents and sometimesthe child under further stress.Intravenous accessA short 24G or 22G cannula in the dorsum of the hand is the commonest method of securing IV access inchildren. The finer 24G cannula may be more difficult to insert, but it is less likely to be felt by the child. The lackof feeling may allow a second attempt to insert the IV if the first attempt failed. The 24G cannula is the usual sizefor neonates and small infants, but in older children it tends to kink when the child moves post op.Positioning for IV access lyTapes and equipment should be prepared before inserting the cannula to facilitate quick fixation, as the child may onmove and dislodge the cannula. If the child lies on the bed, blankets can be placed to hide their hand and restrictmovement. Younger children can also sit across a parent’s lap, with their arm brought under the parent’s arm (see lyFigure 1.1). This position hides the hand from the view of the child and parent and helps to keep it still by placing sthe child at a mechanical disadvantage. on geAssistanceA good assistant is vital to maximise the chances of successful venepuncture. Just using a tourniquet for a young s pachild is unlikely to work. It is important that the assistant holds the child’s hand and arm correctly, aiming to distend gethe veins and prevent withdrawal of the child’s hand. The assistant needs to hold the forearm tight enough to act as atourniquet, but not so tight that the hand turns white from arterial compression. The assistant also gently retracts the e pachild’s skin up the limb which helps to fix the vein. The assistant’s other hand can be placed across the child’s elbow pljoint, which helps prevent sudden limb movement if the child feels the needle (see Figure 1.2, p. 8). The anaesthetistcan stabilise their own arm by resting their elbow on something to compensate for sudden movements by the child. m eTips for venepuncture pl saIf no veins are visible, using the index finger to very gently feel the dorsum of the hand may detect the faint mbulge of an underlying vein. It is best to try this before using antiseptic, as this leaves the skin very slightly sticky,making it much harder to feel subtle variations. Sometimes a faint blue tinge can be seen as an indication of a sa
  22. 22. CHAPTE R 1 A N O V E R V I E W O F PA E D I AT R I C A N A E S T H E S I A 7 All equipment, including tape, is prepared beforehand. The child sits sideways across the seated parent’s lap and is distracted with stickers or a toy. The parent’s arm hugs the child’s back and the child’s arm is brought under the parent’s arm. An assistant stabilises the child’s arm and squeezes it as a tourniquet. The anaesthetist holds the child’s hand and stabilises it for insertion of the cannula. Seated parent, back to anaesthetist and with child sideways on lap. Child’s arm brought under parent’s arm and behind parent’s back Assistant stabilising child’s arm and acting as a tourniquet Anaesthetist holding child’s hand for cannula insertion F I G U R E 1. 1 Po s i t i on i ng t h e c l i n g y o r u n c o o p e r at i ve t o d d l e r f o r i n s e r t i o n o f a n I Vvein. The child’s feet can also be used for induction; IV insertion in the foot, however, is more painful than in thehand. An IV can be left in the foot for postop use depending on the child’s age, length of stay and postoperative lyambulation. Some veins are constant in position and can be accessed on the basis of landmarks only. These sites are:1. the long saphenous vein just in front of the medial malleolus—feel for the groove in the malleolus that contains the vein on ly2. between the fourth and fifth metacarpal bones on the dorsum of the hand s on3. the cephalic vein on the lateral aspect of the forearm, which tends to be in line with the skin crease between ge the thumb and index finger, 1–3 cm proximal to the wrist. Injection of air bubbles is always avoided in children as they may have undiagnosed congenital heart disease s paor a patent foramen ovale allowing bubbles to cross into the arterial circulation. Care to remove air bubbles is gerequired every time a venous line is used. e paInduction pl m eInhalational or intravenous induction is the usual choice, although rectal induction is also used in some European plcountries. There are several advantages and disadvantages to each induction type (see Table 1.4 overleaf) and sathere is often an institutional preference for a particular type. IV induction became more popular after the mintroduction of topical anaesthetic creams. However, an IV can still be sited using nitrous oxide/oxygen anddistraction. Possibly the greatest advantage of the IV induction is that IV access is present from the outset. Some sa
  23. 23. 8 YO U R G U I D E T O PA E D I AT R I C A N A E S T H E S I A The assistant’s hand encircles the child’s forearm. It acts as a tourniquet, retracts the skin on the dorsum of the hand and prevents the child pulling away. Assistant gently retracts child’s skin Assistant’s hand encircling and stabilising child’s arm, and acting as tourniquet Anaesthetist stabilising child’s hand while inserting IV cannula ly F I G U R E 1. 2 Te c hn i qu e f o r I V c an nu l at i o n i n s m a l l c h i l d r e n on lyTable 1.4 Advantages and disadvantages of IV and inhalational induction s on ge IV induction Inhalational induction s pa IV access present No needle ge Less cooperation from child required Gradual loss of airway Less excitatory movement No pain from propofol e No smelly gas Faster wake up than after IV induction pa Less pollution Parent can see what is happening to child pl m e plchildren still hate needles even though they may be old enough to understand that the anaesthetic cream will sawork. Inhalational induction requires skill in distraction and behavioural management to enable the child to mkeep the mask on long enough for the volatile agent to work. Parental presence at induction is standard in mostpaediatric hospitals and is discussed in Chapter 3. sa
  24. 24. CHAPTE R 1 A N O V E R V I E W O F PA E D I AT R I C A N A E S T H E S I A 9 For all paediatric inductions there is a limited window of opportunity to distract the child, after which stressand fear can make the induction increasingly difficult. It is important to be organised with an induction plan, tobrief your assistant before starting and to make sure that all equipment is ready to use.Inhalational inductionSevoflurane is the only available inhalational agent suitable for induction. A routine induction includes 66%nitrous oxide in oxygen for 20–40 seconds, followed by 8% sevoflurane. If the T-piece is used for induction, it isuseful to give the child a few breaths at 0.5% before going to 8% sevoflurane. (The fresh gas flow enters the T-piecevery close to the face mask, and the sudden smell of 8% sevoflurane may be noticed by the child.) There is no need to incrementally increase the sevoflurane during induction as this slows induction andincreases excitatory phenomena The timing of nitrous administration is critical, as too short a time means thatthe child is more likely to reject the mask when sevoflurane is started, and too long a time makes it more likely thechild will either lose interest and cooperation or become dysphoric from the nitrous oxide. Induction is possiblewithout nitrous, but it is more likely that the mask will be rejected. KEY POINT There is no need to incrementally increase sevoflurane concentration during gas induction—this slows induction and increases the incidence of excitatory phenomena. The incremental technique is a hangover from the technique of halothane induction. Some airway obstruction is common after consciousness is lost, due partly to excitatory phenomena thatoccur with sevoflurane (see Chapter 2), and partly due to loss of upper airway tone. Continuous positiveairway pressure (CPAP) and gentle jaw thrust are used to overcome this. Nitrous oxide can be eliminated atthis stage if desired and sevoflurane given in 100% oxygen. An oral airway should not be inserted at this stage. lyIt is important to maintain the sevoflurane at 8% until a deeper level of anaesthesia is reached and this partly onobstructed, excitatory stage has ended. Listening to the heart rate and observing tidal volume will also give aguide to depth and the need to reduce the sevoflurane concentration. Cardiovascular depression occurs with high lyconcentrations of sevoflurane, but in these early stages of inhalational induction it is the airway that will cause sproblems, not hypotension. on geIntravenous inductionIV access is obtained and anaesthesia is induced, most commonly with propofol. Co-induction techniques using s pabenzodiazepines and opioids are uncommonly used in children because it is less important in children to blunt gethe haemodynamic responses to induction and intubation, and the priority is often to induce an upset child asquickly as possible. Preoxygenation and application of monitors before induction are omitted in many centres to e pareduce stress to the child. plRapid sequence induction m eInduction for the child at risk of aspiration follows the same principles as in adults—injection of a precalculated pldose of induction agent followed immediately by a rapidly acting muscle relaxant and cricoid pressure. The samost important difference is that gentle mask ventilation is always given during cricoid pressure. It is difficult mto preoxygenate children and they desaturate quickly if left apnoeic before intubation. This results in a hurried‘crash’ intubation with the risk of morbidity. Cricoid pressure protects the stomach from insufflation during sa
  25. 25. 10 YO U R G U I D E T O PA E D I AT R I C A N A E S T H E S I Amask ventilation. If mask ventilation cannot be achieved during cricoid pressure, the pressure is reduced orremoved completely if ventilation is still difficult. KEY POINT Rapid sequence induction in children includes gentle mask ventilation before intubation. The second major difference from treating adults in rapid sequence induction is that cricoid pressure is oftenomitted in neonates and infants. Cricoid pressure compresses and obstructs the soft, compliant trachea anddistorts the upper airway anatomy. It may not be performed correctly by the assistant if they are not routinelyinvolved in anaesthesia for children. Gastro-oesophageal sphincter tone and minimising the time betweeninduction and intubation are relied on instead of cricoid pressure. The force required for cricoid pressure in adults is about 44  N. Lower pressures (30–40  N, equivalent to3–4 kg) are applied in children and neonates because of their compliant tracheal cartilages. It is well known thatanaesthetic assistants are less skilled at applying cricoid pressure in children. Although suxamethonium is commonly used for rapid sequence induction in children, non-depolarisingrelaxants are also commonly used. This is because they have a fast onset in infants and children and their effectis markedly enhanced by volatile anaesthetic agents given during ventilation before intubation. It is safe tooverpressure the volatile agent dose in most children during induction. Finally, use of a rapid sequence induction does not mandate a cuffed endotracheal tube (ETT). Either a cuffedor uncuffed ETT may be chosen for children with full stomachs—uncuffed ETTs have a long history of safe usein children in this situation. If suxamethonium has been used to facilitate intubation with an uncuffed ETT thatthen needs to be changed because of excessive leak, consider giving a long-acting relaxant before the tube change.Many would re-apply the cricoid pressure during the tube change. lyMaintenance on lyThe choice of technique during maintenance follows the same principles as with adults. The choice of airway s onmanagement and type of ventilation depends on a variety of patient, procedure and anaesthetic factors. Neonates geand small infants are commonly intubated and ventilated for all but the briefest case. Otherwise great care mustbe taken with the issues of rebreathing, respiratory muscle fatigue and loss of a clear airway. Furthermore, as s pathe patient is so small, the surgical field is close to the airway and it is difficult to instrument the airway during gesurgery if problems arise. Another important difference between children (especially preschool-aged) and adults is that more care is e parequired during maintenance to ensure calm and safe emergence. Pain and dysphoria are two important reasons plfor children waking upset and distressed, and these can be minimised during maintenance. Unlike adults whomay suffer in silence from inadequate analgesia, children will let everyone know if they are uncomfortable or m edistressed. pl saHypothermia mHypothermia during anaesthesia is common in both children and adults. Children, however, are more at risk: theyhave a large surface area relative to body weight, so heat production is relatively low compared to environmental sa
  26. 26. CHAPTE R 1 A N O V E R V I E W O F PA E D I AT R I C A N A E S T H E S I A 11 Relative body proportions of infant and adult. Note the relatively large head of the infant, making up 20% of the surface area. Infant Adult F I G U R E 1. 3 Ch an ge s i n b od y p r op o r t i o n s lylosses. Infants and neonates also have reduced ability to generate heat because of absent or reduced shivering. Achild’s head is large in proportion to the rest of the body (see Figure 1.3), so it is a site of significant heat loss if itis not covered. on ly Most heat is lost through the skin via radiation and convection. Losses are minimised by keeping the childcovered, warming the OR (typically to about 21 °C for children, higher for neonates) and using a forced air s onwarmer. ge Conductive heat loss may be large if gel pads are placed under the child to prevent pressure injuries. These gelpads are made of dense visco-elastic polymer with a large thermal mass and will draw heat from the child. They s pashould either not be used, or prewarmed with a forced air warmer. Only about 10% of heat loss is through the geairway, and passive humidification is adequate in paediatric anaesthesia. e paRecovery pl m eThe facilities required for paediatric recovery are the same as for adults and are covered in professional and College plguidelines. Staff should have experience in paediatric recovery and receive ongoing training in resuscitation. saStaffing numbers in paediatric recovery need to be higher as even an awake child needs to be watched closely; for mexample, a child may try to climb out of their cot or bed. As in theatre, paediatric recovery requires the full sizerange of airway and resuscitation equipment. sa
  27. 27. 12 YO U R G U I D E T O PA E D I AT R I C A N A E S T H E S I A Many centres allow parents into recovery. This requires having enough space to accommodate parents, enoughstaff to escort the parent into recovery and a method to ensure privacy for other patients. Most centres wait untilthe child is awake and not at risk of airway problems before allowing the parent in.Common recovery problemsEmergence agitation and deliriumChildren will soon let everyone know if they wake up sore or unhappy. Anaesthetists looking after children arecareful to ensure good analgesia on awakening. Children can be agitated when they wake up for many differentreasons; however, it is important to exclude pain before considering other causes (see Table 1.5). Agitated childrencry and are unhappy but are consolable, recognise their parent and can usually communicate.Table 1.5 Causes of a child waking agitated and crying after anaesthesia Cause of agitation at awakening Pain Full bladder Disorientation Bad taste Bad feeling Parental separation Hypoxia ly Delirium Difficult induction on ly Emergence delirium is a drug-induced disorientation. The child cries or screams, may be hallucinating, is suncooperative and inconsolable, and thrashes around. The child often does not appear to recognise their parent. on geIt is common in preschool-aged children after anaesthesia with sevoflurane and desflurane. The reportedincidence varies enormously because of variations in definition. Rapid awakening seems to contribute, andpropofol maintenance reduces the incidence. Midazolam and other sedatives can paradoxically cause delirium if s pagiven as a premed before short cases where the child wakes before the effect has worn off. Delirium begins as the gechild awakens and usually lasts less than 30 minutes, although it can last longer. Treatment begins with eliminating other causes including hypoxia (although it can be difficult to get accurate e paoximeter readings on a thrashing child) and pain. Reassure the parents, who are usually very distressed at seeing pltheir child behaving like this, and ensure that the child avoids injury. Most children just need observationand time to settle, but others benefit from pharmacological intervention. Consider small doses of propofol m e0.5–2 mg/kg (ensuring equipment is available in case of apnoea), IV clonidine (0.5–1 microgram/kg), or fentanyl pl0.5–1 microgram/kg. Ketamine or dexmedetomidine may also be effective, but midazolam is not effective. Some sacases only improve if the child can be made to sleep for 10 or 15 minutes and re-awaken gradually. Sedation mcalms the child and gives the recovery staff and parents time to regroup from what can be a very harrowingexperience. sa
  28. 28. CHAPTE R 1 A N O V E R V I E W O F PA E D I AT R I C A N A E S T H E S I A 13Oxygen dependenceA proportion of children require oxygen to maintain their oxygen saturation at 96% or above. Oxygen is givenby face mask or with a mask nearby (‘blow-by’ oxygen). Most children won’t tolerate nasal prongs. Small infantscan be given oxygen using a nasopharyngeal catheter and flow rates of 1 litre/min or less. Prolonged oxygendependence after anaesthesia is abnormal and a cause needs to be determined. The commonest reason isa resolving URTI where the child simply needs time to wake up, cough, clear secretions and re-expand theirlungs. However, causes such as aspiration and other pulmonary events need to be borne in mind and excluded ifappropriate. A CXR will help if the child looks unwell or if oxygen is still required for more than an hour or two.Routine chest X-rays are not taken because of concerns about radiation exposure.Discharge from recoveryThis is usually based on criteria or a scoring system rather than time. Scoring systems such as the modifiedAldrete or Steward scores are commonly used. These measure several parameters to give a score, and dischargeoccurs when a certain score is reached. In general, the score ensures the child is conscious, maintaining theirairway, has acceptable oxygen saturation, good pain control, and is not agitated.ComplicationsThis section deals with some of the causes of morbidity after anaesthesia in children.Postoperative nausea and vomiting (PONV)Children under 2 years of age are at low risk of PONV and are not usually given prophylactic antiemetic therapy.PONV is a common problem after this age, however. The incidence is the same in boys and girls until puberty,after which it is higher in girls. There are several procedures with a particularly high incidence of PONV. These lyinclude strabismus repair (up to 70% PONV incidence if no antiemetic given), umbilical hernia repair, prominent onear correction, middle ear surgery and open orthopaedic procedures. An important reason for PONV in all typesof surgery is too much opioid relative to the amount of pain. ly Antiemetic drugs are discussed in Chapter 2. Ondansetron and the other 5HT3 antagonists are effective and swidely used, although cost limits their use in some centres. on gePost extubation stridorA croupy cough or inspiratory stridor is uncommon if care is taken with ETT size selection. However, these s pasymptoms occasionally occur and are due to oedema at the cricoid ring, which narrows the airway and causes geturbulent or obstructed airflow. It is more likely in small children (who already have a small diameter airway),children with a recent URTI (where there may already be some inflammation and oedema of the upper airway), e paor if an ETT was used that was too large (i.e. no leak at 20  cm  H2O pressure or cuff too large to gently pass plthrough cricoid ring). Observation alone may be appropriate if there is no significant obstruction. OtherwiseIV dexamethasone is given if there is concern that obstruction may worsen, or nebulised adrenaline given if m eobstruction is significant (see Table 1.6 overleaf). Racemic adrenaline was incorrectly believed to cause less plarrhythmias and is no longer used; 1% adrenaline solution for nebulisers is now more commonly used. If this sais not available, the 1:1000 (0.1%) IV form of adrenaline can be used. If treatment with adrenaline is required, movernight admission for observation should be considered. Heliox (> 60% helium in oxygen) may be helpful, butmany children won’t tolerate the close-fitting mask that its use requires. sa
  29. 29. 14 YO U R G U I D E T O PA E D I AT R I C A N A E S T H E S I ATable 1.6 Treatment of post extubation croup in recovery Treatment for post extubation croup Dexamethasone IV 0.5–0.6 mg/kg Nebulised adrenaline—2 types available: i) L-isomer adrenaline 1% nebuliser solution 0.05 mL/kg diluted with normal saline to 4 mL Or ii) Adrenaline 1:1000 (IV preparation) 0.5 mL/kg (maximum 5 mL), use undiluted in nebuliser bowlDeep vein thrombosis (DVT)Deep vein thrombosis (DVT) is rare in children, possibly due to high levels in children of the thrombin inhibitoralpha-2 macroglobulin, which only reduce to adult levels during adolescence. Seventy per cent of DVTs occur ininfants and teenagers. Sick neonates in ICU who have a CVC (central venous catheter) are at high risk for venousthromboembolism, but also for complications from thromboprophylaxis. Teenage patients presenting for surgeryare at high risk if they have malignancy, are undergoing major surgery of the pelvis or lower limbs, or have apast history of venous thromboembolism. Factor V Leiden and deficiencies of the regulatory proteins C, S, orAntithrombin III do not appear to be important until puberty. Anti-embolic and compression stockings are used for DVT prevention in children who are at risk and largeenough for them to fit. Low molecular weight heparin (enoxaparin) 0.75 mg/kg (maximum 20 mg) twice a day isgiven to children older than 6 months by vertical subcutaneous injection in the lower abdomen. This is preferablygiven two hours before surgery, but otherwise after induction. The adult dose of 40 mg once a day can be usedin children heavier than 40 kg. Factor Xa levels and platelet count are checked on day one if heparin is continuedpostop. One per cent of children develop heparin-induced thrombocytopenia. lyAspiration onAspiration is rare but slightly more common in children than adults. The incidence in children is about 1 in2–3000. Children have less sequelae after aspiration than adults. Even in the presence of CXR changes, they lyusually improve very quickly without specific therapy. Reflux symptoms are common in infants and young schildren, but are not necessarily an indication for a rapid sequence induction. Medications to reduce the risk of on geaspiration are not usually used in children because of the rarity of aspiration and sequelae. A child who aspirates asmall amount is usually oxygen dependent for a period after anaesthesia and is admitted for observation. s paAwareness geAwareness in children (0.5–1.0%) is quite different to adults (0.1–0.2%). It is more common, may occur in non-paralysed children without signs of inadequate anaesthesia, and does not seem to cause distress or post-traumatic e pastress disorder. The reason for the high incidence of awareness in children is not known. There is concern that it may plreflect problems in the questionnaire methodology used in studies of awareness—children may be more suggestibleand more likely to report memories on repeated questioning. They may also have a diminished ability to encode and m econsolidate memory, making it difficult to differentiate true memories from imagined events and dreams. pl saLaryngospasm mLaryngospasm most commonly occurs at induction and emergence, but occasionally in recovery. All paediatricrecovery areas should have the equipment, training and procedures to deal with this. It can be prevented by sa

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