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1,000 Practice MTF MCQs for the Primary and Final FRCA 1,000 Practice MTF MCQs for the Primary and Final FRCA Edited by Hozefa Ebrahim University Hospitals, Birmingham Michael Clarke Worcestershire Acute Hospitals NHS Trust Hussein Khambalia Health Education England, North West Insiya Susnerwala Health Education England, North West Richard Pierson The Dudley Group NHS Foundation Trust Anna Pierson The Dudley Group NHS Foundation Trust Natish Bindal Queen Elizabeth Hospital Birmingham University Printing House, Cambridge CB2 8BS, United Kingdom One Liberty Plaza, 20th Floor, New York, NY 10006, USA 477 Williamstown Road, Port Melbourne, VIC 3207, Australia 314–321, 3rd Floor, Plot 3, Splendor Forum, Jasola District Centre, New Delhi – 110025, India 79 Anson Road, #06–04/06, Singapore 079906 Cambridge University Press is part of the University of Cambridge. It furthers the University’s mission by disseminating knowledge in the pursuit of education, learning, and research at the highest international levels of excellence. www.cambridge.org Information on this title: www.cambridge.org/9781108465830 DOI: 10.1017/9781108566100 © Cambridge University Press 2019 This publication is in copyright. Subject to statutory exception and to the provisions of relevant collective licensing agreements, no reproduction of any part may take place without the written permission of Cambridge University Press. First published 2019 Printed and bound in Great Britain by Clays Ltd, Elcograf S.p.A. A catalogue record for this publication is available from the British Library. Library of Congress Cataloging-in-Publication Data Names: Ebrahim, Hozefa, editor. Title: 1,000 practice MTF MCQs for the primary and ﬁnal FRCA / edited by Hozefa Ebrahim [and six others]. Other titles: 1000 practice MTF MCQs for the primary and ﬁnal FRCA | One thousand practice MTF MCQs for the primary and ﬁnal FRCA Description: Cambridge, United Kingdom ; New York, NY : Cambridge University Press, 2019. | Includes index. Identiﬁers: LCCN 2018037315 | ISBN 9781108465830 (paperback) Subjects: | MESH: Royal College of Anaesthetists (Great Britain) | Anesthesia – methods | Anesthetics – pharmacology | United Kingdom | Examination Questions Classiﬁcation: LCC RD81 | NLM WO 218.2 | DDC 617.9/6–dc23 LC record available at https://lccn.loc.gov/2018037315 ISBN 978-1-108-46583-0 Paperback 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 guarantee that any content on such websites is, or will remain, accurate or appropriate.......................................................................................................................................................................................... Every eﬀort has been made in preparing this book to provide accurate and up-to-date information that 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 book. Readers are strongly advised to pay careful attention to information provided by the manufacturer of any drugs or equipment that they plan to use. Contents List of Contributors vi Foreword by Dr Tina McLeod ix Preface xi Acknowledgements xii List of Abbreviations xiii 1a Physiology Questions 1 4b Physics Answers 299 1b Physiology Answers 33 5a Clinical Anaesthesia Questions 334 2a Anatomy Questions 99 5b Clinical Anaesthesia Answers 426 2b Anatomy Answers 133 3a Pharmacology Questions 178 3b Pharmacology Answers 210 Index 547 4a Physics Questions 264 v Contributors Suji Abraham Nick Dodds Consultant Anaesthetist Specialist Trainee in Anaesthesia Worcestershire Acute Hospitals and Intensive Care Medicine NHS Trust Severn Deanery Irmeet Banga Laura Dyal Specialist Registrar in Anaesthesia Specialist Registrar in Anaesthesia West Midlands Deanery West Midlands Deanery Rajneesh Bankenahally Hozefa Ebrahim Consultant Anaesthetist Consultant in Anaesthesia Heart of England NHS Trust University Hospitals, Birmingham Natish Bindal Ian Ewington Consultant Anaesthetist Consultant Anaesthetist Queen Elizabeth Hospital Birmingham Queen Elizabeth Hospital Birmingham Lowri Bowen Richard Hodgson Consultant Anaesthetist Consultant Anaesthetist Children’s Hospital for Wales, Cardiﬀ The County Hospital, Hereford Toni Brunning Chaitra Holla Specialist Registrar in Anaesthesia Specialist Registrar in Anaesthesia Worcestershire Acute NHS Trust Heart of England NHS Trust Michael Clarke Consultant Anaesthetist Phillip Howells Worcestershire Acute Hospitals NHS Trust Specialist Trainee Birmingham School of Anaesthesia Ed Copley Health Education England, West Midlands Consultant Anaesthetist Northamptonshire Hussein Khambalia Specialist Trainee in Transplant Surgery Satinder Dalay Health Education England, ST7 Anaesthetics North West Birmingham School of Anaesthesia Laura Kocierz Matt Davies Specialist Registrar in Anaesthesia Consultant Anaesthetist West Midlands Deanery Russells Hall Hospital, Dudley vi List of Contributors vii Sajith Kumar University Hospital of Coventry and Consultant Anaesthetist Warwickshire Heart of England NHS Trust Philip Pemberton Ramy Labib Specialist Registrar in Anaesthesia Consultant Anaesthetist West Midlands Deanery Worcestershire Acute Hospitals NHS Trust Anna Pierson Consultant Anaesthetist Nicholas Lascelles The Dudley Group NHS Foundation Trust Specialist Registrar in Anaesthesia Gloucester Royal Hospital Richard Pierson Consultant Anaesthetist Katherine Laver The Dudley Group NHS Foundation Specialist Trainee in Anaesthesia Trust and Intensive Care Medicine West Midlands Deanery Jane Pilsbury Consultant Anaesthetist Peter Lax University Hospitals Birmingham Consultant in Anaesthetics and Intensive Care Medicine Nagendra Pinnamaneni RAF Tactical Medical Wing Specialist Registrar in Anaesthesia East Midlands Deanery Adam Low Consultant Anaesthetist Priya Ramchandran Queen Elizabeth Hospital, Birmingham Specialist Registrar in Anaesthesia West Midlands Deanery Vivienne Madden Specialist Registrar in Anaesthesia Carla Richardson West Midlands Deanery Consultant Anaesthetist and Critical Care Harsha Mistry University Hospitals Birmingham Specialist Registrar in Anaesthesia West Midlands Deanery Karim Rizkallah ST8, General Surgery Rachel Moore North West Deanery Consultant Anaesthetist University Hospitals Birmingham Ahmed Salama Specialist Trainee in Anaesthesia Singaraselvan Nagarajan West Midlands Deanery Associate Consultant, Women’s Anaesthesia Sandeep Sharma KK Women’s and Children’s Hospital, Specialty Doctor Singapore Birmingham Heartlands Hospital Rajen Nathwani Naginder Singh Consultant in Anaesthesia and Intensive Consultant Anaesthetist Care Medicine Queen Elizabeth Hospital Birmingham viii List of Contributors Insiya Susnerwala Laura Tulloch Specialist Trainee in Anaesthesia Consultant in Anaesthesia and Health Education England North West Intensive Care Medicine Worcester Acute Hospitals NHS Trust Robert Tipping Consultant Anaesthetist Elenor Whittingham Queen Elizabeth Hospital Specialist Registrar in Anaesthesia Birmingham West Midlands Deanery Foreword There have been a number of single best answer books published recently, but there is a paucity of new true–false multiple-choice books. Whilst the internet provides a welcome educational resource, it is often unregulated and of variable quality and a book such as this, which is accurately researched, is a valuable addition to the bookshelf. The ethos of this book is problem-based learning, which has many advantages over the traditional textbook in that it provides information in digestible bite-sized chunks. This book has 1000 true–false multiple choice questions. The 600 basic science questions comprise 150 in each of anatomy, physiology, pharmacology and physics and will be useful for candidates sitting both the primary and the ﬁnal FRCA. The 400 clinical questions are geared toward ﬁnal FRCA candidates, making this a unique MCQ book which can be used throughout the examination journey. Whilst the questions are useful for exam practice, the answers provide a wealth of information, including key diagrams, and this publication is therefore a useful textbook in its own right. It can be used by trainees and trainers as a base of knowledge for viva practice and should be available in every department. I congratulate Dr Ebrahim and his co-authors on the production of this book – which I strongly recommend to all anaesthetists. Dr Tina McLeod MBBS FRCA Consultant Anaesthetist, Heart of England NHS Foundation Trust ix Preface Revising for exams can be a period of mixed emotions. Some enjoy the challenge of learning new material, but a great many ﬁnd it a time of stress. Let us make that time easier for you. One quiet afternoon in the coﬀee room, I heard some of my dear trainees stressing over some bad questions. It is true that some questions are poorly written – not in this book, I hope, as all of our questions have been written by seasoned educationalists and peer reviewed by many exam candidates – but nevertheless, books and the internet are littered with ambiguous questions. Indeed, the right answer can change with time. However, I tried to reassure them that any question that has caused them to discuss these ambiguities would surely have resulted in them gaining more knowledge. These words appeared to help, although I knew that any added stress at this diﬃcult time was far from welcome. Studying for exams is as much about having the right positive attitude as it is about cramming information! The basic sciences for the FRCA exam are well deﬁned. This book has 150 questions for each of the four basic sciences – anatomy, physics, pharmacology and physiology. The questions have been written to cover the entire syllabus. It is our suggestion that you only start practising MCQs once you have spent appropriate time reading the core material. Find some quiet time to complete a predetermined number of questions, under exam conditions. Mark them, and then go through your results. For stems in which you are scoring 4s and 5s, you clearly have a good grasp of the topic. Pat yourself on the back and move on. For stems in which you are scoring 3 or less, after reading our explanation, spend just a few more minutes concentrating on reading more about that topic. We do not advise going back to the drawing board and spending hours rereading the entire topic, as this will not be the best use of your time. Five minutes of targeted reading usually yields the majority of information needed for that question. Use this technique for the clinical questions as well. The FRCA examination-setters are not trying to trick you. The MCQ exam is a test of knowledge. If you ﬁnd a particular question easy, it is probably because you have got the knowledge. If a question is diﬃcult, spend some time reading that topic. In our experience, time well spent always pays oﬀ. Keep a positive mental attitude. That quiet afternoon, a few of us made the decision to compile the best of our questions, and embark upon another project. I hope this book is helpful to you. And please remember, one day you’ll be the teacher. Good luck. xi Acknowledgements Firstly, I extend my gratitude to Dr Syedna Mohammed Burhanuddin for all his wisdom throughout my life. Without him, I would not be where I am. So many people have given us support along the way, in many diﬀerent guises; I thank those who have drafted questions and explanations, proof-read our work, given suggestions for the content, given us encouragement along the way, and kept the project going. Thank you! To consultants, programme training directors, regional advisors, trainees and jobbing consultants who have given us inspiration, experience and education throughout our years as doctors. To Ellie Whittingham for her help with the illustrations. Ellie is a perfect combination of scientist and artist. To Mike, Richard, Anna, Hussein, Insiya and Natish for being good friends and excellent authors. Thanks for tolerating my incessant emails, phone calls and corridor-pestering! Finally, thank you to all our families for allowing us to hide in our studies typing away. Tasneem, Mustafa and Farida Ebrahim, Charlotte Norris, Amelia and James Clarke, George and Henry Pierson, Umme-Hani and Abbas Khambalia, Sudesh and Munishwar Bindal, thank you! xii Abbreviations A&E accident and emergency AAA abdominal aortic aneurysm AAGBI Association of Anaesthetists of Great Britain and Ireland ABG arterial blood gas ABP arterial blood pressure ACE angiotensin-converting enzyme ACh acetylcholine ACT activated clotting time ACTH adrenocorticotrophic hormone ADCC antibody-dependent cell-mediated cytotoxicity ADH antidiuretic hormone ADHD attention deﬁcit hyperactivity disorder AFE amniotic ﬂuid embolism AFLP acute fatty liver of pregnancy AFOI awake ﬁbreoptic intubation AKI acute kidney injury ALF acute liver failure ALI acute lung injury ALP alkaline phosphatase ALS advanced life support ALT alanine aminotransferase AMPA α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid ANP atrial natriuretic peptide ANS autonomic nervous system AOP apnoea of prematurity APACHE Acute Physiology And Chronic Health Evaluation APTT activated partial thromboplastin time ARDS acute respiratory distress syndrome AS aortic stenosis ASA American Society of Anesthesiologists ASD atrial septal defect ASIS anterior superior iliac spine AST aspartate aminotransferase ATLS advanced trauma life support ATP adenosine triphosphate AV atrioventricular BBB blood–brain barrier BCIS bone cement implantation syndrome BG blood glucose BiPAP bilevel positive airway pressure BIS bispectral index BMI body mass index BMR basal metabolic rate xiii xiv List of Abbreviations BP blood pressure BSA burn surface area BTS British Thoracic Society BZD benzodiazepine CABG coronary artery bypass graft cAMP cyclic adenosine monophosphate CBF cerebral blood ﬂow CDH congenital diaphragmatic hernia CEPOD Conﬁdential Enquiry into Perioperative Deaths CFAM cerebral function analyzing monitor cGMP cyclic guanosine monophosphate CHEOPS Children’s Hospital of Eastern Ontario Pain Scale CIM critical illness myopathy CIP critical illness polyneuropathy cLMA classic laryngeal mask airway CLP cleft lip and palate CMAP compound muscle action potential CMRO2 cerebral metabolic oxygen requirement CMV cytomegalovirus CN cranial nerve CNB central neuraxial block CNS central nervous system CO cardiac output COETT cuﬀed oral endotracheal tube COHb carboxyhaemoglobin COMT catechol-О-methyl transferase COPD chronic obstructive pulmonary disease COX cyclo-oxygenase CP cerebral palsy CPAP continuous positive airway pressure CPET cardiopulmonary exercise testing CPD citrate phosphate dextrose CPR cardiopulmonary resuscitation CPSP chronic postsurgical pain CRF continuous radiofrequency CRH corticotropin-releasing hormone CRMO2 cerebral metabolic rate for oxygen CRPS complex regional pain syndrome CRT cathode ray tube CS caesarean section CSE combined spinal–epidural CSF cerebrospinal ﬂuid CT computerized tomography CTG cardiotocography CTPA computerized tomography pulmonary angiography CTZ chemoreceptor trigger zone CVC central venous catheter List of Abbreviations xv CVO combined ventricular output CVP central venous pressure CVS cardiovascular CXR chest X-ray CYP cytochrome P450 DA ductus arteriosus DAG diacylglycerol DAS Diﬃcult Airway Society DI diabetes insipidus DJ duodenojejunal DLCO diﬀusing capacity of the lungs for carbon monoxide DLT double lumen tube DNA deoxyribonucleic acid DOPA dihydroxyphenylalanine DP dorsalis pedis 2,3-DPG 2,3-diphosphoglycerate DPP4 dipeptidyl peptidase 4 DVT deep vein thrombosis DXA dual-energy X-ray absorptiometry EBP epidural blood patch ECF extracellular ﬂuid ECG electrocardiogram ECMO extracorporeal membrane oxygenation ECST European Carotid Surgery Trial ECT electroconvulsive therapy ED emergency department ED50 eﬀective dose 50% EDV end diastolic volume EEG electroencephalogram EMG electromyography EMLA eutectic mixture of local anaesthetics ENT ear nose and throat ESV end systolic volume ESWL extracorporeal shock-wave lithotripsy ETCO2 end tidal carbon dioxide ETT endotracheal tube EVAR endovascular aortic aneurysm repair FAD+ ﬂavin adenine dinucleotide (oxidized form) FADH ﬂavin adenine dinucleotide (reduced form) FBC full blood count FCP ﬁnal common pathway FDG ﬂuorodeoxyglucose FEF forced expiratory ﬂow FEV1 forced expiratory volume in 1 second FFP fresh frozen plasma FiO2 fraction of inspired oxygen FRC functional residual capacity xvi List of Abbreviations FSH follicle-stimulating hormone FVC forced vital capacity GA general anaesthetic GABA γ amino-butyric acid GBS Guillain–Barré syndrome GCS Glasgow coma score GDP guanosine diphosphate GFR glomerular ﬁltration rate GH growth hormone GHB γ-hydroxybutyrate GI gastrointestinal GLP glucagon-like peptide GnRH gonadotropin-releasing hormone GORD gastro-oesophageal reﬂux disease GPCR G-protein-coupled receptor GTN glyceryl trinitrate GTP guanosine triphosphate GU genitourinary HALF hyperacute liver failure Hb haemoglobin HbA adult haemoglobin HbF fetal haemoglobin hCG human chorionic gonadotropin HDL high-density lipoprotein HDU high-dependency unit HELLP haemolysis, elevated liver enzymes and low platelets HES hydroxyethyl starch HFOV high-frequency oscillatory ventilation HII high-impact interventions HIV human immunodeﬁciency virus HLA human leucocyte antigen HLHS hypoplastic left heart syndrome HME heat and moisture exchanger HOCM hypertrophic obstructive cardiomyopathy hPL human placental lactogen HPV hypoxic pulmonary vasoconstriction HR heart rate HRT hormone replacement therapy 5-HT 5-hydroxytryptamine HZ herpes zoster IABP intra-aortic balloon pump IAP intra-abdominal pressure IBW ideal body weight ICA internal carotid artery ICD intercostal chest drain ICF intracellular ﬂuid ICP intracranial pressure List of Abbreviations xvii ICU intensive care unit IE infective endocarditis IF intrinsic factor IJV internal jugular vein IM intramuscular INR international normalized ratio IOP intraocular pressure IP3 inositol triphosphate IPPV intermittent positive pressure ventilation ISF interstitial ﬂuid ITP3 inositol triphosphate IV intravenous IVC inferior vena cava IVF intravascular ﬂuid LA local anaesthetic LAD left anterior descending artery LAP left atrial pressure LBBB left bundle branch block LD50 lethal dose 50% LDH lactate dehydrogenase LFJV low-frequency jet ventilation LH luteinizing hormone LIF left iliac fossa LMA laryngeal mask airway LMWH low molecular weight heparin LOAF lateral two lumbricals, opponens pollicis, abductor pollicis brevis and ﬂexor pollicis brevis LOR loss of resistance LOS lower oesophageal sphincter LRA locoregional anaesthesia LV left ventricle LVEDV left ventricular end diastolic volume LVEF left ventricular ejection fraction LVESV left ventricular end systolic volume LVH left ventricular hypertrophy LVRS lung volume reduction surgery MA maximum amplitude MAC minimum alveolar concentration MAO monoamine oxidase MawP mean airway pressure MDMA 3,4-methylenedioxy-N-methylamphetamine (Ecstacy) MEN multiple endocrine neoplasia MEP motor evoked potentials MET metabolic equivalent MG myasthenia gravis MH malignant hyperpyrexia MHRA Medicines and Healthcare Products Regulatory Agency xviii List of Abbreviations MI myocardial infarction MPAP mean pulmonary artery pressure MR magnetic resonance MRI magnetic resonance imaging NAD+ nicotinamide adenine dinucleotide (oxidized form) NADH nicotinamide adenine dinucleotide (reduced form) NAP3 Third National Audit Project NASCET North American Symptomatic Carotid Endarterectomy Trial NCA nurse-controlled analgesia NDMR non-depolarizing muscle relaxant NDNMB non-depolarizing neuromuscular block NEC necrotizing enterocolitis NG nasogastric NICU neonatal intensive care unit NK neurokinin NKCC Na-K-2Cl co-transporter NMDA N-methyl-D-aspartate NMJ neuromuscular junction NNBC National Network for Burn Care NNT number needed to treat NR Reynold’s number NRS numerical rating scale NSAID non-steroidal anti-inﬂammatory drug NTS nucleus tractus solitarius NYHA New York Heart Association OA osteoarthritis ODP operating department practitioner OHDC oxygen–haemoglobin dissociation curve OLV one-lung ventilation ORIF open reduction internal ﬁxation OSA obstructive sleep apnoea PA pulmonary artery PAC pulmonary artery catheter paCO2 arterial partial pressure of carbon dioxide pACO2 alveolar partial pressure of carbon dioxide PAFC pulmonary artery ﬂotation catheter paO2 arterial partial pressure of oxygen pAO2 alveolar partial pressure of oxygen PAP pulmonary arterial pressure PAWP pumonary artery wedge pressure PCA patient-controlled analgesia PCEA patient-controlled epidural analgesia PCI percutaneous coronary intervention pcjO2 conjunctival oxygen tension PCWP pulmonary capillary wedge pressure PD Parkinson’s disease PDA patent ductus arteriosus List of Abbreviations xix PDE phosphodiesterase PDPH post-dural-puncture headache PEEP positive end-expiratory pressure PEFR peak expiratory ﬂow rate PET positron emission tomography PFO patent foramen ovale PGA postgestational age PGE2 prostaglandin E2 PGI2 prostacyclin PH pulmonary hypertension PHN postherpatic neuralgia PICU paediatric intensive care unit PIP2 phosphatidylinositol PMCS perimortem caesarean section PNMT phenylethanolamine N-methyl transferase PNS peripheral nervous system POCD postoperative cognitive dysfunction PONV postoperative nausea and vomiting PPAR peroxisome proliferator-activated receptor PPH postpartum haemorrhage PPI proton pump inhibitor ppoFEV1% predicted postoperative FEV1 percentage PRF pulsed radiofrequency PRL prolactin PSIS posterior superior iliac spine PSNS parasympathetic nervous system PT prothrombin time PTH parathyroid hormone PVR pulmonary vascular resistence QAI quaternary ammonium ion QTc corrected QT RA right atrium RCOG Royal College of Obstetricians and Gynaecologists REM rapid eye movement RER respiratory exchange ratio RF radiofrequency RMP resting membrane potential RMS root mean square RNA ribonucleic acid ROS reactive oxygen species ROSC return of spontaneous circulation RQ respiratory quotient RR respiratory rate RRT renal replacement therapy RSI rapid sequence induction rSO2 regional cerebral oxygen saturation RTA road traﬃc accident xx List of Abbreviations RUL right upper lobe RUQ right upper quadrant RV right ventricle RVLM rostral ventrolateral medulla RVOT right ventricular outﬂow obstruction SA sinoatrial SAD supraglottic airway device SAH subarachnoid haemorrhage SCS spinal cord stimulation SCUF slow continuous ultraﬁltration SE status epilepticus SIP sympathetically independent pain SIRS systemic inﬂammatory response syndrome SLED sustained low-eﬃciency dialysis SMP sympathetically maintained pain SNAP sensory nerve action potential SNP sodium nitroprusside SNR signal-to-noise ratio SP stump pressure SPECT single-photon emission computed tomography SSEP somatosensory evoked potential STP standard temperature and pressure SVP saturated vapour pressure SVR systemic vascular resistance SVT supraventricular tachycardia T3 triiodothyronine T4 thyroxine TACO transfusion-associated circulatory overload TAP transversus abdominis plane TBSA total body surface area TCI target-controlled infusion TCD transcranial Doppler ultrasound TEG thromboelastogram TENS transcutaneous electrical nerve stimulation TFPI tissue factor pathway inhibitor TH cells T-helper cells TIA transient ischaemic attack TIVA total intravenous anaesthesia TLC total lung capacity TMJ temporomandibular joint TN trigeminal neuralgia TOF train of four or tracheo-oesophageal ﬁstula TPN total parenteral nutrition TRALI transfusion-related acute lung injury TRAM transverse rectus abdominis myocutaneous TRH thyrotropin-releasing hormone TRVP transient receptor potential vanilloid List of Abbreviations xxi TSH thyroid-stimulating hormone TURP transurethral resection of the prostate UFH unfractionated heparin URTI upper respiratory tract infection USS ultrasound scan VAE venous air embolism VAS visual analogue scale VC vital capacity VD volume of distribution VF ventricular ﬁbrillation VRIII variable rate intravenous insulin infusion VRS visual rating scale VSD ventricular septal defect VT ventricular tachycardia VTE venous thromboembolism VZV varicella zoster virus WFNS World Federation of Neurosurgeons WPW Wolﬀ–Parkinson–White syndrome Chapter Physiology Questions 1a Question 1 Regarding cardiac muscle structure, which of the following statements are correct?: a. The volume of the left ventricle is maximal at the atrial end systolic pause b. The right coronary artery usually supplies both the right atrium and ventricle, and part of the left atrium c. Cardiac muscle cells have one nucleus, but many mitochondria d. Striated cardiac muscle ﬁbres are more structured than skeletal muscle ﬁbres e. The sarcoplasmic reticulum sequesters calcium via a Na+/K+-ATPase pump Question 2 Regarding conduction through the heart: a. Conduction through the cardiac septum is usually uni-directional from left to right b. Left bundle branch block usually produces left axis deviation on the 12-lead ECG c. Right bundle branch block usually produces right axis deviation on the 12-lead ECG d. Stimulation of the tenth cranial nerve induces slowing of AV conduction e. Wolﬀ–Parkinson–White syndrome is always associated with an accessory conducting bundle Question 3 With regard to the cardiac action potential: a. Sodium inﬂux via fast sodium channels occurs during phase 0 of the nodal cardiac action potential b. The absolute refractory period extends into phase 3 of the action potential c. The plateau phase is due to a decrease in cell membrane permeability of calcium d. The Na+/K+ pump is involved in the restoration of ionic gradients in phase 4 of the nodal action potential e. Slow L-type Ca2+ channels are involved in both nodal and conduction system action potentials Question 4 Regarding automaticity with the sinoatrial (SA) node and the atrioventricular (AV) node: a. The SA node is principally responsible for the heart’s automaticity b. The threshold potential for the nodal action potential is –90 mV 1 2 Chapter 1a: Physiology Questions c. Parasympathetic stimulation of the SA node causes a slowing of heart rate via an increase in membrane Ca2+ permeability d. The SA node does not have an absolute refractory period e. The AV node has a longer phase 4 than the SA node Question 5 With regard to the cardiac cycle: a. The ﬁrst heart sound represents the closure of the aortic valve b. The second heart sound occurs at the beginning of the T wave on the ECG c. The peak of left ventricular pressure occurs with the QRS complex on the ECG d. Ventricular volume begins to increase when the atrioventricular valves open e. The peak of aortic pressure corresponds with the T wave Question 6 This question concerns the cardiac cycle – diastole, perfusion, lusitropy: a. The myocardium is entirely dependent on perfusion occurring during diastole b. Lusitropy refers to the myocardial relaxation c. At rest diastole accounts for 0.5 seconds of a cardiac cycle lasting 0.8 seconds d. Ventricular ﬁlling is rapid during early diastole e. Atrial contraction during late diastole accounts for the majority of end diastolic ven- tricular volume Question 7 With respect to the CVP waveform: a. Irregular cannon ‘a waves’ are due to complete heart block b. The ‘v wave’ is smaller in tricuspid incompetence c. Normal CVP is 0–8 mmHg d. The ‘y descent’ is demonstrating passive ventricular ﬁlling e. The ‘c wave’ is the tallest wave Question 8 This question concerns the P-V relationship, and the Frank–Starling curve: a. The Frank–Starling law states that the force of contraction is related to the initial ﬁbre length b. The force of myocardial contraction is proportional to the initial ﬁbre length, until an upper limit is reached c. Before the mitral valve opens there is a decrease in pressure in the ventricle, but no change in volume d. Before aortic valve closure there is an increase in volume with no associated change in pressure e. The aortic valve opens when the pressure in the ventricle is lower than that in the aorta Chapter 1a: Physiology Questions 3 Question 9 With respect to cardiac output formulae: a. CO = HR × (ESV – EDV) b. The Fick principle cannot be used to calculate blood ﬂow through the liver c. Only calculated values are used in the Fick equation d. The oxygen uptake forms the denominator in the Fick equation e. Shunts do not aﬀect the accuracy of the calculation of cardiac output via the Fick principle Question 10 Regarding preload, afterload and contractility: a. Afterload is increased by peripheral vasoconstriction b. Increased afterload causes an increased stroke volume c. Preload can be likened to end systolic volume d. Preload can be estimated by measurement of CVP e. Preload and afterload are the only factors aﬀecting contractility Question 11 Regarding heart rate and coronary blood ﬂow: a. The sympathetic outﬂow controlling heart rate is via T1–T8 b. The right coronary artery is the dominant vessel in half the population c. The right coronary artery arises from the posterior aortic sinus d. Atrial natriuretic peptide (ANP) is a vasodilator e. The nucleus ambiguus is involved in integration of the aﬀerent inputs aﬀecting heart rate from baroreceptors, chemoreceptors and higher centres Question 12 With regard to the Valsalva manoeuvre: a. A square wave response is seen in autonomic neuropathy b. A diminished chemoreceptor reﬂex causes the abnormal response in autonomic neuropathy c. It can be used to terminate supraventricular tachycardia d. The fall in blood pressure is exaggerated in patients under spinal anaesthesia e. It decreases the intensity of most heart murmurs on auscultation Question 13 With regard to the physiological control of blood pressure: a. Baroreceptors in the carotid sinus are innervated by the vagus nerve b. The vasomotor centres are found in the hypothalamus and medulla c. Higher centres have no inﬂuence on the vasomotor centres d. Low pressure baroreceptors are found in the atria, ventricles and pulmonary vessels e. The Bainbridge reﬂex causes a reﬂex bradycardia 4 Chapter 1a: Physiology Questions Question 14 With regard to the left ventricular end diastolic volume: a. In a normal heart it is approximately 30 ml b. It is a measure of preload c. It is reduced in exercise d. It is independent of ventricular compliance e. It is increased in diastolic heart failure Question 15 The following will cause arterioles to constrict: a. Direct injury to the vessel b. Decreased tissue pH c. Decreased tissue oxygen tension d. Thromboxane A2 e. Bradykinin Question 16 The following mediators cause vasoconstriction in vascular smooth muscle: a. Epinephrine b. PGF2α c. Serotonin d. PGI2 e. Adenosine Question 17 The following factors may predispose to turbulent ﬂow within a tube: a. Small diameter b. Large diameter c. High viscosity d. Low velocity e. High density Question 18 The following statements are true regarding the lymphatic system: a. Lymph contains clotting factors b. Protein content of lymph is generally more than that of plasma c. The lymphatic system contains valves d. Skeletal muscle contraction aids lymphatic ﬂow e. The thoracic duct is the largest lymphatic vessel Chapter 1a: Physiology Questions 5 Question 19 Regarding blood ﬂow in arterioles and capillaries: a. Arterioles are the main site of resistance to blood ﬂow b. Blood ﬂow in capillaries is pulsatile c. Capillaries have no smooth muscle d. Changes in temperature can aﬀect ﬂow e. Precapillary sphincters have rich sympathetic innervation Question 20 In a rigid tube: a. Flow is directly proportional to the fourth power of the radius b. Flow is inversely proportional to the pressure diﬀerence c. Resistance is directly proportional to the length d. Resistance is directly proportional to the square of the radius e. If the radius is doubled, the resistance is increased by 16 times Question 21 The following lung volumes or capacities can be measured by spirometry: a. Functional residual capacity b. Vital capacity c. Total lung capacity d. Inspiratory reserve volume e. Expiratory reserve volume Question 22 Regarding lung compliance: a. The normal total lung compliance is 200 cmH2O.ml−1 b. Static compliance is greater than dynamic compliance c. Compliance is increased when a patient is supine d. It is determined by the gradient of the pressure–volume curve e. It is greatly reduced in acute respiratory distress syndrome (ARDS) Question 23 Regarding respiratory dead space: a. In dead space, the V/Q ratio is zero b. As dead space increases, paCO2 falls c. It is increased by general anaesthesia d. Total dead space is determined using the Bohr equation e. It is greater in the apices of the lungs than the bases 6 Chapter 1a: Physiology Questions Question 24 When referring to work of breathing: a. It is determined by the area inside a pressure–volume curve b. Inspiratory work is that which overcomes the elastic recoil of the thoracic wall c. Expiratory work is that which overcomes airway resistance d. Work to overcome non-elastic forces is lost as heat e. Respiratory work increases in a ventilated patient Question 25 Regarding the functional residual capacity (FRC): a. It is approximately 30 ml.kg−1 b. Pulmonary vascular resistance is highest at FRC c. It may be less than the closing capacity d. It is increased under anaesthesia e. It is decreased in pregnancy Question 26 Concerning respiratory mechanics: a. The diaphragm is responsible for 50% of the air that enters the lungs during spontaneous respiration b. A third of the diaphragmatic ﬁbres are slow twitch ﬁbres c. The transpulmonary pressure is equal to the diﬀerence between the pressure within the lungs and the intrapleural pressure d. The accessory muscles of respiration serve to stabilize the upper rib cage and to prevent in-drawing in normal respiration e. Compliance of the lung is deﬁned as the change in pressure per unit change in volume Question 27 Concerning surfactant: a. Before 32–34 weeks’ gestation, its production is inadequate and this predisposes to respiratory distress syndrome b. Type II alveolar epithelial cells are responsible for its production c. Less ﬂuid is drawn from capillaries into alveoli as a result of its action d. The hysteresis area of the pressure–volume loop is increased as a result of its action in reducing surface tension e. Larger alveoli are seen to collapse more readily as a result of its action Question 28 Regarding ventilation and perfusion matching in the upright lung: a. From apex to base, ventilation increases; blood ﬂow also increases, but less rapidly b. The ventilation/perfusion ratio is higher at the apex of the lung and decreases progres- sively towards the base of the lung Chapter 1a: Physiology Questions 7 c. The diﬀerence in partial pressures between the apex and base of the lung is greater for carbon dioxide compared with that for oxygen d. Hypoxaemia that results from ventilation/perfusion inequality can be corrected by an increase in ventilation e. Pulmonary emboli result in an increase in the ventilation/perfusion ratio Question 29 Concerning alveolar ventilation and the alveolar gas equation: a. At rest, the level of alveolar ventilation is the main determinant of the pO2 of alveolar gas b. Hypoventilation always results in an increased arterial pressure of carbon dioxide in the blood stream c. The respiratory quotient is calculated by the oxygen consumption divided by the carbon dioxide production d. Faced with hyperventilation, it takes longer for pCO2 to reach equilibrium as compared with pO2 e. Shunt refers to areas of the lungs where ventilation is adequate, but perfusion is deﬁcient Question 30 Concerning the distribution of blood ﬂow in the lung described by West: a. Zone 1 does not exist under normal conditions b. In zone 2, the diﬀerence between alveolar and arterial pressures determines blood ﬂow c. In zone 3: Pa > PA > Pv where Pv = venous pressure, Pa = arterial pressure and PA = alveolar pressure d. From apex to base, the pressure responsible for driving blood ﬂow increases e. In zone 2, the arteriovenous pressure diﬀerence determines blood ﬂow Question 31 With reference to intermittent positive pressure ventilation (IPPV): a. The addition of positive end-expiratory pressure (PEEP) increases the dead space b. It increases the functional residual capacity (FRC) c. It reduces V/Q mismatch d. It results in an increase in antidiuretic hormone (ADH) secretion e. High airway pressures cause a decrease in pulmonary vascular resistance Question 32 At high altitude (2500 m above sea level): a. The FiO2 is 20.9% b. The oxygen–haemoglobin dissociation curve (OHDC) is moved to the right initially c. Hypoxic pulmonary vasoconstriction is beneﬁcial 8 Chapter 1a: Physiology Questions d. There is increased 2,3-DPG production e. Polycythaemia is the most eﬀective feature of acclimatization Question 33 The non-respiratory functions of the lungs include: a. Immune function mediated by pulmonary alveolar macrophages b. Epinephrine breakdown c. Angiotensin I production d. Fibrinolysis of blood clots in the pulmonary circulation e. Drug metabolism by the cytochrome p450 system Question 34 Increased oxygen binding to haemoglobin occurs with: a. 2,3-DPG b. HbF c. Methaemoglobin d. Bohr eﬀect e. Haldane eﬀect Question 35 Central chemoreceptors directly increase minute ventilation in response to: a. Hypercarbia b. Hypoxia c. Acidosis d. Hyperthermia e. Anaemia Question 36 Regarding the haemoglobin buﬀering system: a. Haemoglobin is a weak acid b. It increases plasma bicarbonate c. It increases plasma chloride d. It has a pKa of 8.1 when deoxygenated e. It is facilitated by plasma carbonic anhydrase Question 37 Prolonged oxygen therapy at atmospheric pressure can cause: a. Cough b. Retrolental ﬁbroplasia c. Pulmonary oedema d. Renal failure e. Tremors Chapter 1a: Physiology Questions 9 Question 38 Acute respiratory failure can be a feature of: a. Aspirin overdose b. Tetanus c. Hypersensitivity pneumonitis d. Poliomyelitis e. Guillain–Barré syndrome Question 39 Diagnostic criteria for acute lung injury include: a. Acute onset b. Air bronchograms on chest radiograph c. Pulmonary artery wedge pressure (PAWP) Pv. This situation does not arise under Chapter 1b: Physiology Answers 49 normal conditions, but can occur with positive pressure ventilation or, alternatively, when arterial blood ﬂow is compromized (massive haemorrhage). In Zone 2: Pa>PA>Pv and, so, it is here that the diﬀerence in arterial and alveolar pressures determines blood ﬂow. While the alveolar pressure is relatively constant throughout the lung, the arterial pressure and therefore the pressure driving blood ﬂow increase down the zone. This eﬀect observed in Zone 2 is referred to as the Starling resistor, sluice or waterfall eﬀect. In Zone 3, Pa>Pv>PA, i.e. the venous pressure now exceeds the alveolar pressure and so it is here that the arteriovenous pressure diﬀerence determines blood ﬂow in the usual way. Like Zone 2, an increase in blood ﬂow is also observed down this zone, attributed to increased capillary dilatation moving downward through the zone. Question 31: TFFTF IPPV results in some unfavourable pulmonary physiological eﬀects such as: maldistribution of gas, progressive atelectasis with a reduced FRC, increased ventilation/perfusion (V/Q) mismatch, decreased compliance and a reduction in surfactant. In spontaneously breathing patients, both ventilation and perfusion are preferentially dis- tributed to the dependent zones of the lungs. With IPPV, preferential ventilation of the non- dependent regions occurs (due to lower resistance to ﬂow), resulting in increased V/Q mismatch. IPPV in the supine position leads to decreased FRC, due in part to decreased lung volume from cephalad displacement by the diaphragm and abdominal contents. The loss of lung volume contributes to atelectasis and reduced compliance. Pulmonary hypoperfusion from IPPV, especially in the non-dependent regions with maldistribution of gas, leads to increased alveolar dead space ventilation. Dead space ventilation increases with rapid respiratory rates, age and lung pathology. Pulmonary vascular resistance (PVR) is increased at very high lung volumes due to stretch of the pulmonary vessels and low lung volumes due to compression of the pulmon- ary vessels. PVR is lowest at FRC. PEEP is used to reduce airways resistance (wider calibre airways at higher FRC), increase FRC and to prevent or reverse lung collapse. PEEP increases anatomical dead space. Most cardiovascular side eﬀects of IPPV correlate with mean intrathoracic pressure and reduced venous return. Humoral eﬀects of IPPV include an increase in ADH, renin–angiotensin and atrial natriuretic peptide, leading to overall retention of sodium and water. Question 32: TFFTF Barometric pressure decreases exponentially as the distance from the Earth’s surface increases. The partial pressure of oxygen decreases at increasing altitude, but the composi- tion of air (e.g. the FiO2) does not change. The compensatory changes to high altitude can be divided into acute and chronic. The most important acute physiological response to high altitude is hyperventilation. Hyperventilation is triggered by hypoxic stimulation of the peripheral chemoreceptors. The resultant hypocarbia and respiratory alkalosis lead to a leftward shift of the oxygen dissociation curve. The respiratory alkalosis is slowly corrected by renal compensation. The respiratory alkalosis stimulates increased 2,3-DPG production and eventually causes the OHDC to move towards the right, thus improving oxygen delivery to the tissues. Pulmonary 50 Chapter 1b: Physiology Answers vasoconstriction also occurs in response to alveolar hypoxia. This increases the pulmonary arterial pressures and increases the strain on the right heart. One of the body’s chronic responses to high altitude includes polycythaemia due to increased erythropoietin release from the kidney. Although the additional oxygen-carrying capacity is beneﬁcial, polycythaemia also causes increased blood viscosity, which negates some of its beneﬁcial eﬀects. Chronic hypoxic pulmonary vasoconstriction causes right ventricular hypertrophy. Myoglobin concentration increases and peripheral capillary pro- liferation occurs. Question 33: TFFTT The lung is responsible for several important non-respiratory functions. These functions include: Vascular reservoir: The pulmonary circulation has extremely distensible vasculature; this enables it to cope with large ﬂuxes in venous return, particularly during exercise and postural changes. Changes in pulmonary vascular volume are also inﬂuenced by the sympathetic nervous system. 70–100 ml of blood is contained within the pulmonary capillaries, which takes part in gas exchange. Filter for blood: Clots, ﬁbrin clumps and air bubbles are all ﬁltered from peripheral venous blood by the lungs, preventing them from entering the systemic circulation. Pulmonary endothelium also produces substances (ﬁbrinolysin activator) that break down blood clots in the pulmonary circulation. Immune function: The mucociliary escalator is the ﬁrst of line defence against inhaled physical substances. As well as a physical barrier, the lungs provide an immune function that is mediated by pulmonary alveolar macrophages and a variety of immune mediators. Immunoglobulins (IgA) are also present in the bronchial secretions. Endocrine and metabolic function: The pulmonary endothelium selectively takes up norepinephrine and serotonin from circulating blood while sparing histamine, dopamine and epinephrine; 30% of norepinephrine and 98% of serotonin is removed by this process. Angiotensin-converting enzyme (ACE) is present in large quantities in the pulmonary vascular endothelium. Angiotensin I is converted to the vasoactive peptide angiotensin II by ACE. Drug metabolism: The lung is a small but important extrahepatic site for drug metabolism by the cytochrome P450 system. The system is easily saturated, but unlike the hepatocytes, cannot be induced. Major role in acid/base balance Question 34: FTFFF Haemoglobin (Hb) is the protein responsible for carrying almost all of the oxygen within the blood; only a small percentage of oxygen is dissolved in solution. Hb is composed of four subunits, each consisting of a haem group and a globin chain. The haem group itself is composed of a protoporphyrin ring containing iron in its ferrous state (Fe2+) at the centre. The Hb molecule has four binding sites for oxygen (the iron atoms in the four haem groups) and therefore is able to cooperatively and reversibly bind up to four oxygen molecules. Oxygen can only bind to iron in the ferrous state. Methaemoglobin contains iron in the ferric/oxidized state (Fe3+) and hence cannot carry oxygen. Chapter 1b: Physiology Answers 51 Adult haemoglobin (HbA) has two α and two β globin chains, whereas fetal haemoglobin (HbF) contains two γ and two α chains. When fully saturated, each gram of HbA carries 1.306 ml of oxygen. However, when fully saturated, HbF will carry more, at 1.312 ml.g−1. This allows placental transfer of oxygen from mother to fetus. Increases in 2,3-DPG, hydrogen ion and carbon dioxide concentrations all reduce the access of oxygen to the haem portion as a result of a conformational change within the Hb molecule (by manipulating bonds between amino acids). This results in decreased aﬃnity of Hb for oxygen. 2,3-DPG is a by-product of glycolysis, speciﬁcally reducing oxygen aﬃnity by binding to the β chains. Therefore, more oxygen may be oﬄoaded to the tissues, a survival beneﬁt. The reduction in oxygen–Hb aﬃnity in the presence of an increased carbon dioxide or hydrogen ion concentration, or an increase in temperature, is known as the Bohr eﬀect. The Haldane eﬀect has no bearing on oxygen binding, but refers to the increased ability of deoxygenated blood to carry carbon dioxide. Conversely, oxygenated blood has a reduced capacity for carbon dioxide. Question 35: TFFFF Minute ventilation is inﬂuenced by information from both central and peripheral chemo- receptors, which relay signals to the medullary respiratory centre. Central chemoreceptors are situated in the ventrolateral medulla near the respiratory centre and are stimulated predominantly by a rise in hydrogen ion concentration within the nearby cerebrospinal ﬂuid (CSF). However, circulating H+ ions are unable to cross the tight junctions of the blood–brain barrier (BBB), and therefore, central chemoreceptors are not inﬂuenced by plasma pH. Their predominant mode of action is to increase ventilation in response to hypercarbia. Unlike H+ ions, circulating CO2, which is raised in respiratory acidosis, is able to cross the BBB. Within the CSF, the excess CO2 combines with H2O to form carbonic acid. This dissociates to form H+ ions, which then stimulate the central chemoreceptors. Central chemoreceptors are unaﬀected by hypoxia. CO2 þ H2 ⇌ H2 CO3 ⇌ Hþ þ HCO 3 Hypoxia is the predominant stimulus for the peripheral chemoreceptors. These are situated in the carotid and aortic bodies and relay information to the medulla via the glossopharyngeal and vagus nerves, respectively. These specialized receptors are richly invested with capillary networks and derive their oxygen needs from dissolved oxygen; hence they are very sensitive to ﬂuctuations in low oxygen tensions. Do not confuse this with conditions where the content of oxygen is decreased, e.g. anaemia (where oxygen tension may be normal, despite the low content). The carotid and aortic bodies also respond to the carbon dioxide tension and plasma pH, but these are less inﬂuential than hypoxia. Control of ventilation is mainly inﬂuenced by the central chemoreceptors, which are very sensitive to small ﬂuctuations in CSF pH. Signiﬁcant degrees of hypoxia are required to stimulate the peripheral receptors. However, their role becomes more signiﬁcant at altitude or in cases of chronic carbon dioxide retention, where there is blunting of the central receptor response. An increase in body temperature does stimulate ventilation, but this is via the respiratory centre directly, not the chemoreceptors. 52 Chapter 1b: Physiology Answers Question 36: TTFTF Haemoglobin is the primary non-bicarbonate buﬀer in the extracellular ﬂuid. It is a weak acid and acts as a buﬀer by accepting hydrogen ions (through its histidine residue). This is another example of the action of carbonic anhydrase; during acidic conditions, plasma carbon dioxide diﬀuses into the erythrocyte where it combines with water to form carbonic acid in a reaction catalyzed by erythrocyte carbonic anhydrase. Carbonic acid then dis- sociates to form hydrogen ions and bicarbonate. H+ binds to histidine residues on the globulin chains. Bicarbonate then diﬀuses out of the erythrocytes into the plasma. To maintain electrical neutrality of the cell, chloride ions diﬀuse into the erythrocytes from the plasma (‘chloride shift’) (Hamburger eﬀect). Deoxygenated haemoglobin is a more powerful buﬀer than its oxygenated counterpart. It has a pKa of 8.1 versus 6.8, hence it is less acidic and acts as a more eﬀective base to accept the protonated H+. Deoxygenated blood is therefore a more eﬀective carrier of carbon dioxide at the tissue level. The converse is seen at the lungs, where oxygenated blood is less able to bind CO2, which is ‘oﬄoaded’ and eliminated from the body. This is known as the Haldane eﬀect. Although there is a signiﬁcant diﬀerence in the amount of CO2 carried in arterial and venous blood, haemoglobin is such an eﬀective buﬀering system that there is only a small diﬀerence between the pH of arterial and venous blood. Question 37: TTTFF Oxygen therapy should be administered and prescribed appropriately; under certain conditions it can be toxic, with a host of deleterious side eﬀects. Oxygen toxicity is caused by exposure to oxygen at partial pressures greater than those to which the body is generally accustomed. This occurs in three principal settings: underwater diving, hyperbaric oxygen chambers and supple- mental oxygen therapy. Toxicity is related to free radical production. These reactive oxygen species can damage cell structures and result in oxidative stress to certain tissues. The goal of supplemental oxygen therapy is usually to use the lowest FiO2 possible for the minimum time in order to ensure adequate tissue oxygenation. With regards to duration of oxygen therapy and risk of toxicity, FiO2 1.0 should be limited to a period of less than 12 hours, FiO2 0.8 to less than 24 hours and FiO2 0.6 to less than 36 hours. Pulmonary eﬀects of toxicity are more common, and occur with exposure to FiO2 of 0.5 or more at atmospheric pressure. Symptoms result from airway and pulmonary inﬂamma- tion and include a ‘tickle’ leading to frequent coughing. If oxygen is not discontinued, this can progress to dyspnoea, substernal discomfort, pulmonary oedema and ﬁnally ARDS due to diﬀuse alveolar damage. Historically, this was known as the Lorrain–Smith eﬀect. Breathing 100% oxygen eventually leads to absorption atelectasis. The neonate is especially at risk following exposure to high inspired oxygen concentra- tions. Retrolental ﬁbroplasia is strongly associated with hyperoxia in the developing infant (although the mechanism diﬀers). Preterm newborns are known to be at higher risk for bronchopulmonary dysplasia. Others at higher risk include patients on mechanical ventila- tion (with FiO2 >0.5) and those on particular chemotherapy agents, such as bleomycin. Exposure to partial pressures of oxygen above 160 kPa, i.e. supra-atmospheric, for as little as a few minutes is associated with central nervous system toxicity. Therefore, those most at risk are underwater divers and patients having hyperbaric oxygen therapy. Toxicity is characterized by perioral twitching, tinnitus, confusion, seizures and drowsiness (Paul Chapter 1b: Physiology Answers 53 Bert eﬀect). Tremors are usually associated with hypercarbia and renal failure is not known to occur as a result of hyperoxia. Question 38: FFTTT Acute respiratory failure is a common reason for admission to critical care units. It is often secondary to lower respiratory tract infection, but there are other important causes. The concept of a critical care unit, with respiratory support, arose from the polio epidemics of the 1950s. The polio virus can damage motor neurones, including those that supply intercostal nerves. Polio patients with respiratory failure were originally treated with negative pressure ventilators (‘iron lungs’). Poliomyelitis is now almost completely eradi- cated in the UK due to vaccination. Tetanus results from infection with tetanus toxoid produced by Clostridium tetani. This potent neurotoxin aﬀects striated, skeletal muscle and causes tetanic contractions such as trismus and opisthotonus. Acute respiratory failure is not a feature. Guillain–Barré syndrome is an acute, ascending polyneuropathy, which has a sudden onset and aﬀects the peripheral nervous system. This can involve paralysis of the diaphragm, subsequent respiratory failure, and potentially a requirement for intubation and ventilation. Hypersensitivity pneumonitis is an alternative term for extrinsic allergic alveolitis. It may be triggered by a range of allergens (including plastics, hay and pigeon feathers), which cause an acute hypersensitivity reaction similar to asthma, but which may progress to chronic pulmonary ﬁbrosis. Aspirin in overdose stimulates the respiratory centre in the medulla, causing hyperventi- lation and respiratory alkalosis. If a patient with known aspirin overdose shows signs of respiratory failure, this should raise the suspicion of ingestion of other drugs. Question 39: TFFFT Acute lung injury (ALI) is a common condition that is characterized by acute severe hypoxia that is not due to left atrial hypertension. The term ALI encompasses a continuum of clinical and radiographic pulmonary changes, with acute respiratory distress syndrome (ARDS) being at the most severe end of the spectrum. ALI is still associated with a high mortality and, in essence, is the presence of non-cardiogenic pulmonary oedema and respiratory failure in the critically ill patient. Correct diagnosis of ALI is essential as other causes of hypoxaemia may be present that are more easily treated. The deﬁnition in current use was described in 1994 at the American–European Consensus Conference and was created in order to make it easier to classify and study the diseases epidemiologically. Strengths of these criteria are that they are clinically relevant and easy to use. Weaknesses are that they are non-speciﬁc and subject to interpretation. Diagnostic criteria are: acute onset, bilateral inﬁltrates on chest X-ray consistent with oedema (air bronchograms may be seen, but these are not diagnostic), pulmonary artery wedge pressure (PAWP) 80 × 109 l–1 should be targeted d. This patient should be taken immediately to theatre for caesarean section e. Cell salvage should not be used because of risk of amniotic ﬂuid embolism Question 314 During your obstetric on-call you are asked to site an epidural in a labouring patient. A student midwife asks about the anatomy of the epidural space. What structures might you possibly encounter? a. Spinal nerves b. Venous plexus c. Ligamentum ﬂavum d. Dural sac e. Fat Question 315 The following are correct regarding sedation in children: a. IV access is necessary if a child is to be sedated for painless imaging with oral chloral hydrate b. A child should be adequately fasted before sedation with nitrous oxide c. Ketamine 2 mg.kg–1 IV may be suitable sedation for a painful procedure in the ER d. Chloral hydrate up to a dose of 100 mg.kg–1 would be suitable sedation for a 50 kg child undergoing painless imaging e. Midazolam IV at a starting dose of 25–50 μg.kg–1 is suitable sedation for an adolescent undergoing a dental procedure 406 Chapter 5a: Clinical Anaesthesia Questions Question 316 The following is true regarding glucose metabolism in the neonate: a. The fetus cannot make glucose from glycogen b. The liver storage of glycogen is suﬃcient for 10–12 hours of fasting c. In the ﬁrst few days of life, the brain can use ketone bodies as a source of energy without harm d. Blood sugar level less than 3.5 mmol.l–1 should be treated e. Neonatal hypoglycaemia can result in long-term developmental defects Question 317 Regarding transthoracic electrical bioimpedance: a. It is a non-invasive method of measuring cardiac output b. It measures electrical resistance of the thorax to a high-frequency, low-magnitude current c. The bioimpedance is directly proportional to the volume of thoracic ﬂuid d. It is ideal for intraoperative cardiac output measurement e. It is accurate when used on awake patients Question 318 The long-term use of strong opioids in the management of chronic non-cancer pain is associated with the development of the following: a. Diabetes b. Erectile dysfunction c. Hypertension d. Reduced libido e. Immune dysfunction Question 319 Regarding acute spinal cord injury: a. It is associated with head injury in up to two-thirds of cases b. Autonomic hyper-reﬂexia typically occurs at an interval of 8–12 weeks post injury c. The timeframe for paralytic ileus is up to 6–8 weeks post injury d. The timeframe for ﬂaccid paralysis is up to 2–3 weeks post injury e. With central cord injury, lower limbs are aﬀected to a greater extent than upper limbs Question 320 You are anaesthetizing a 66-year-old female undergoing a partial maxillectomy and recon- struction with radial forearm ﬂap. Regarding ﬂap surgery: a. The ambient temperature in theatre should be maintained at 22–24 °C b. Central venous pressure should be monitored c. Tramadol can be used to treat postoperative shivering Chapter 5a: Clinical Anaesthesia Questions 407 d. Norepinephrine should be used to maintain MAP >70 mmHg e. The ideal diﬀerence between central and core temperature is 55 years) are more likely to develop CPSP d. Severe pain immediately following mastectomy is a risk factor for CPSP e. Perioperative gabapentin is associated with a reduction in CPSP Question 338 The following people should be scheduled for elective surgery for repair of an abdominal aortic aneurysm: a. Patients with aneurysms larger than 9.0 cm in diameter b. Patients with aneurysms larger than 4.5 cm in diameter that have increased by more than 1 cm in the past year c. Symptomatic aneurysms of 4.5–5.5 cm d. Symptomatic aneurysms of less than 4.5 cm in diameter that have increased by more than 1 cm in the past year e. All of the above Question 339 You have been asked to anaesthetize a 5 kg six-week-old baby for a pyloromyotomy following a diagnostic ultrasound that revealed pyloric stenosis. Which of the following is true regarding this condition? a. As soon as the diagnosis is conﬁrmed this becomes an urgent surgical case and should be operated on within the hour b. The common biochemical derangement is a hyperchloraemic metabolic alkalosis c. Insertion of an NG tube will be diﬃcult due to obstruction and should not be attempted d. Pyloric stenosis is the commonest surgical condition presenting within the ﬁrst six months of life e. Urinary chloride levels are useful in assessing degree of dehydration and ﬁlling Question 340 In a patient with sepsis: a. Indicators of sepsis may include mottled hands, raised bilirubin or raised procalcitonin b. Venoconstriction by noradrenaline will compensate for hypovolaemia when resusci- tating septic patients 412 Chapter 5a: Clinical Anaesthesia Questions c. Low-dose dopamine infusion can be used to increase splanchnic ﬂow and reduce acute kidney injury d. Dobutamine may be trialled in low cardiac output states e. Target blood pressure should be a systolic at 90 mmHg Question 341 With regards to third-degree heart block preoperatively: a. Insertion of a temporary transvenous pacing wire may be appropriate b. May indicate myocardial ischaemia c. An isoprenaline infusion may improve heart rate d. Transcutaneous pacing may be necessary e. It may be transient Question 342 Phase 1 metabolism is principally undertaken in the liver and involves cytochrome P450 enzymes. The following are cyctochrome P450 inducers: a. Phenytoin b. Rifampicin c. Omeprazole d. Grapefruit juice e. Fluconazole Question 343 Which of the following statements are true regarding the management of hyperglycaemia in critically ill patients? a. Tight glycaemic control is beneﬁcial in severe sepsis when compared with conventional control b. Glucose meter readings from a capillary ﬁnger-stick are comparable to blood gas analyzers c. Acute drops in blood glucose are less tolerated in patients with well-established diabetes mellitus d. The latest evidence suggests targeting a blood glucose level below 8 mmol.l−1 e. Wide ﬂuctuations in blood glucose are more hazardous than sustained hyperglycaemia Question 344 In a pregnant woman with a mechanical heart valve: a. Low molecular weight heparin is as eﬀective as warfarin at preventing valve thrombosis b. Unfractionated heparin crosses the placenta c. There is a higher miscarriage and stillbirth rate with warfarin use when compared to heparin d. Both unfractionated and low molecular weight heparins can be used throughout preg- nancy for thrombus prevention e. Epidurals are a suitable form of labour analgesia Chapter 5a: Clinical Anaesthesia Questions 413 Question 345 Clinical features associated with Parkinson’s disease include: a. Myoclonus b. Hypokinesia c. Jerking d. Postural instability e. Intention tremor Question 346 Concerning anaesthetic drugs and the elderly: a. Reduced doses of neuromuscular drugs are required, owing to reduced muscle mass b. MAC values of inhalational agents are reduced by 20–30% c. β-receptor sensitivity is reduced, resulting in a reduction in response to exogenous β-agonists d. Intravenous and inhalational anaesthetic agents can suppress the cardiac and smooth muscle contractility e. Duration of action of opioids and benzodiazepines exhibits an age-related increase in the elimination half-life Question 347 With regards to upper respiratory tract infections: a. There is increased risk of laryngospasm and bronchospasm during general anaesthesia b. Haemophilus inﬂuenzae is the commonest cause of retropharyngeal abscess c. Respiratory syncytial virus can cause laryngitis, tracheitis and bronchitis d. In epiglottitis bacteraemia is unlikely e. Croup requires ventilatory support in 20% of cases Question 348 The ODP is helping you set up for a spinal anaesthetic and realizes there are no more spinal needles in the room. He oﬀers you the choice of needle. Which of the following are suitable for spinal anaesthesia? a. Quinke b. Hustead c. Sprotte d. Whitacre e. Weiss Question 349 Regarding supraglottic airway devices: a. The classic LMA can achieve a median pharyngeal seal of approximately 20 cmH20 b. The i-Gel has a relatively low oesophageal seal pressure c. The ProSeal LMA has an anterior inﬂatable cuﬀ 414 Chapter 5a: Clinical Anaesthesia Questions d. When seated correctly, the tip of the ProSeal LMA sits over the oesophageal inlet e. Paediatric sizes of the ProSeal LMA are available Question 350 The following are true regarding hypocalcaemia of the neonate: a. Infants of insulin-dependant diabetic mothers are at risk b. Cow’s milk ingestion is not a risk c. Neonatal seizures may be the ﬁrst manifestation in neonates d. Electrocardiographic evaluation is often not characteristic e. Treatment intraoperatively should be prompted by hypotension Question 351 With regards to ophthalmic needle blocks: a. If the axial globe length is >26 mm, retrobulbar block is preferred to minimize the risk of globe penetration b. If the axial globe length is >26 mm there is a high risk of globe penetration if a sub- Tenon block is performed c. The axial globe length will usually be 1000 mg per 24 hours c. Seizures d. Epigastric pain e. Pulmonary oedema Question 384 Pyridostigmine is used in the treatment of myasthenia gravis. Regarding pyridostigmine: a. It acts by decreasing the amount of acetylcholine at the neuromuscular junction b. Has a peak eﬀect eight hours after administration c. Does not cross the blood–brain barrier d. Has a longer duration of action than neostigmine e. Is administered as a subcutaneous injection Question 385 Regarding tests of pulmonary function and lung volumes: a. All lung volumes can be measured with a spirometer b. In ﬂow–volume loops, the starting point of the loop is the residual volume 422 Chapter 5a: Clinical Anaesthesia Questions c. Dynamic compression of the airways results in a ﬁxed ﬂow rate during expiration d. Intrathoracic and extrathoracic obstruction have the same eﬀect on ﬂow–volume loops e. Predicted peak expiratory ﬂow rates are based on height and age Question 386 A patient is admitted to the ITU for inotropic support and ﬂuid management. A decision is made to site a central venous catheter in the internal jugular vein (IJV). With regards to anatomical relations to the IJV: a. The internal carotid artery is medial b. The thoracic duct is anterior c. The dome of pleura is posterior d. The omohyoid passes anterior e. The vagus nerve is posterior Question 387 With regards to anaesthesia for ophthalmic surgery: a. Sedation is required in less than 2% of cataract procedures b. A BMI ≥35 is a contraindication to day-case ophthalmic surgery c. It is not generally necessary to starve patients prior to ophthalmic surgery under local anaesthesia d. Appropriately trained non-medical staﬀ may administer peribulbar blocks e. Intravenous access is obtained only if sedation is likely to be required Question 388 During microvascular ﬂap surgery: a. Haematocrit should be maintained around 40% b. Sodium nitroprusside can be used to increase ﬂap blood ﬂow c. Hypervolaemia is recommended to ensure vasodilatation and optimum ﬂap blood ﬂow d. Hypercapnia is desirable to produce vasodilatation and optimum ﬂap blood ﬂow e. Remifentanil use is associated with hypotension and reduced ﬂap blood ﬂow Question 389 With regards to patients undergoing surgery for abdominal aortic aneurysm: a. Statins should be started one month before intervention and continued indeﬁnitely b. β-Blockers should be started one week before intervention and continued indeﬁnitely c. Patients with cardiac risk factors should undergo preoperative cardiopulmonary exer- cise testing d. In the case of a ruptured aneurysm the systolic blood pressure should be kept between 50 and 100 mmHg to maintain hypotensive haemostasis e. Although aspirin may be continued perioperatively, dual antiplatelet therapy must be stopped at least seven days preoperatively to reduce the risk of bleeding Chapter 5a: Clinical Anaesthesia Questions 423 Question 390 A 55-year-old male presents for a right nephrectomy. He has a background of chronic lower back pain and normally takes morphine sulfate 100 mg twice daily. He has declined an epidural to control postoperative pain. Which of the following would correctly replace his background opioid requirements over 24 hours? a. IV morphine 33 mg per 24 h b. IV morphine 66 mg per 24 h c. IV morphine 2.75 mg.h–1 d. IV morphine 5.25 mg.h–1 e. SC diamorphine 50 mg per 24 h Question 391 A 60-year-old woman presents for parathyroid surgery. Prior to induction of anaesthesia: a. Serum calcium should be less than 4 mmol.l–1 b. CT scanning of the neck is mandatory c. Screening for other endocrine diseases should be considered d. All patients should receive steroids e. All patients should be screened for a long QT interval Question 392 Conditions associated with phaeochromocytoma include: a. Multiple endocrine neoplasia 1 b. Multiple endocrine neoplasia 2 c. Von Recklinghausen’s disease d. Von Hippel–Lindau syndrome e. Klippel–Trenaunay syndrome Question 393 A 30-year-old male was brought to the ED one hour following ingestion of antifreeze. The following options are correct regarding further management: a. Activated charcoal may be useful in this case b. Haemoﬁltration may be indicated c. He is likely to develop a metabolic acidosis with a high anion gap d. The toxin involved usually follows ﬁrst-order kinetics e. IV fomepizole is indicated based on the above history Question 394 Obesity aﬀects the pharmacokinetics of intravenous anaesthetic drugs. Which of the following drugs should have dosing based on ideal body weight? a. Propofol b. Rocuronium c. Vecuronium 424 Chapter 5a: Clinical Anaesthesia Questions d. Paracetamol e. Morphine Question 395 Co-morbidities are aﬀected by fat distribution in obese patients. Regarding an android fat distribution: a. It increases likelihood of a diﬃcult airway b. It increases the likelihood of diﬃcult venous access c. It increases the likelihood of diﬃculties in ventilation d. It increases the likelihood of metabolic co-morbidities e. It decreases the likelihood of cardiovascular co-morbidities Question 396 A 68-year-old male presents to the ED with severe dyspnoea and resolved chest pain. His ECG shows sinus tachycardia with a rate of 130 min–1 and no ST segment changes. His BP is 90/42 mmHg, RR is 44 min–1 and his SpO2 is 92% on FiO2 of 1.0. He is known to be diabetic, hypertensive and suﬀers from ischaemic heart disease. He also gives a history of previous DVT two years ago. Which of the following decisions is appropriate regarding his management? a. Immediate thrombolysis if cardiac arrest is imminent b. Urgent CTPA followed by thrombolysis if pulmonary embolism is detected c. Stabilize the patient on ICU then request an urgent echo and CTPA d. Bedside echocardiogram followed by thrombolysis if the right ventricle is dilated e. Bedside echocardiogram followed by immediate percutaneous coronary intervention if there is a wall motion abnormality Question 397 The following statements are correct regarding infective endocarditis: a. Streptococcus viridans is the most common organism causing infective endocarditis b. Fungal endocarditis usually requires surgical intervention c. Anticoagulation is indicated once vegetations are conﬁrmed by echocardiography d. Streptococcus bovis raises the suspicion of intestinal malignancy e. At least two sets of blood cultures should be taken before starting antibiotics Question 398 The following are signs of a developing total spinal: a. Increasing anxiety or sense of panic b. Hypotension and bradycardia c. Tingling in the ﬁngers d. Sudden whispering voice e. Respiratory arrest Chapter 5a: Clinical Anaesthesia Questions 425 Question 399 The following are true in the management of the pregnant trauma patient over 20 weeks’ gestation: a. Around 5–7% of pregnant women undergo some form of trauma b. Once the primary survey has been completed then manual displacement of the uterus must be performed c. In patients with pelvic fractures there is a fetal mortality incidence of up to 25% d. Uterine rupture is rare, even with direct abdominal trauma e. Placental abruption occurs in 3–4% of minor trauma cases Question 400 You are asked to anaesthetize a term neonate for correction of tracheo-oesophageal ﬁstula (TOF), which was diagnosed antenatally. Which of the following statements are correct? a. 50% of patients with oesophageal atresia will have another congenital abnormality b. Surgery should take place within the ﬁrst 24 hours of birth c. The Spitz classiﬁcation is used to describe the anatomical variations of oesophageal atresia and TOF d. Failure to pass an NG tube is commonly the only diagnostic sign e. IV induction is preferred over gaseous induction Chapter Clinical Anaesthesia Answers 5b Question 1: FFFTF Malignant hyperthermia (MH) is a rare autosomal dominant condition. If this patient’s biological father had MH his risk is likely to be 50%. The responsible gene mutation is on chromosome 19 in the majority of patients, resulting in three abnormal isoforms of the ryanodine receptors in muscle (plasma cholinesterase is coded for on chromosome 3). Up to 15 relevant mutations at chromosome 19 have been identiﬁed and point mutations may occur, resulting in cases with no relevant family history. The abnormality results in an abnormal ryanodine calcium channel in muscle that allows excessive calcium to move from the endoplasmic reticulum into the cytoplasm, with uncontrolled muscle contraction. Dantrolene is used to treat MH by uncoupling the excitation contraction process and blocking the ryanodine calcium channel. MH may develop after exposure to triggering agents, with some reports up to 12 hours post exposure, and can occur after previous uneventful general anaesthetics. Question 2: TTFFT In children a cuﬀed tube is not always used, in order to prevent tracheal stenosis; an uncuﬀed tube can provide a secure airway due to the anatomical variation in children. A method of detecting CO2 will conﬁrm placement, but continuous capnography is not the only available method; in prehospital practice a colorimetric device is used. Question 3: TFFFT The Third National Audit Project of the Royal College of Anaesthetists (NAP3) investigated the major complications following central neuraxial block. Staphylococcus aureus was found to be the most common organism associated with epidural abscesses. The majority of complications following perioperative central neuraxial block (CNB) occurred with epidur- als. Vertebral canal haematoma commonly presents with symptoms of leg weakness. In NAP3 weak legs were a universal symptom in cases of vertebral canal haematoma, but back pain was rare. The incidence of permanent injury after adult perioperative epidural was 8.2–17.4 per 100 000. The incidence of paraplegia and death following CNB was found to be 0.7–1.8 per 100 000. Question 4: FTTFT Cyanotic heart disease is a group of illnesses in which the deoxygenated blood travels to the systemic circulation without entering the pulmonary circulation (right to left shunt). 426 Chapter 5b: Clinical Anaesthesia Answers 427 In coarctation of the aorta there is no alteration of the normal ﬂow but rather stenosis in the descending thoracic aorta. Tetralogy of Fallot is characterized by right ventricular outﬂow obstruction, VSD, aortic root over-riding a high VSD and RV hypertrophy. Thus the blood is shunted from the right ventricle to the aorta. After birth the pulmonary vascular resistance (PVR) drops below the SVR making any shunt through ASD or VSD almost always a left to right shunt. Only when complicated with severe pulmonary hypertension (Eisenmenger’s syndrome) does the reversal of shunt occur leading to cyanosis in condi- tions with isolated septal defects. Question 5: TFFTT One metabolic equivalent (MET) is equivalent to 3.5 ml.kg–1.min–1 oxygen consumption and represents the oxygen consumption of an adult at rest. Patients should be able to perform more than 4 METS to undertake major surgery, which correlates clinically to being able to climb at least one ﬂight of stairs. MET values of activities range from 0.9 (sleeping) to 23 (running at 22.5 km.h–1). Question 6: FFFFF Myasthenic syndrome is a diagnosis related to myasthenia gravis (MG), also known as Eaton–Lambert syndrome. There are some important features of myasthenic syndrome distinguishing it from MG. There is decreased release of acetylcholine from the presynaptic nerve terminal, as opposed to IgG autoantibodies directed at the postsynaptic acetylcholine receptor seen in MG. Muscle weakness in myasthenic syndrome predominantly aﬀects the proximal muscles, as opposed to the generalized pattern often with ocular and bulbar muscle involvement seen in MG. Weakness in MG is typically worse on exertion and improves with rest and the opposite pattern is true in myasthenic syndrome, with electro- myography showing an increase in power on titanic stimulation. Patients with myasthenic syndrome show an increased sensitivity to both depolarizing and non-depolarizing muscle relaxants. In MG there is increased sensitivity to non-depolarizing muscle relaxants, but a relative resistance to suxamethonium, with up to twice the normal dose being required. Acetylcholinesterase inhibitors (such as neostigmine and more commonly pydridostig- mine) are a mainstay in the pharmacological treatment of MG, but result only in slight improvement in muscle weakness in myasthenic syndrome. Other features of myasthenic syndrome not seen in MG include autonomic system disturbance and the depression or absence of tendon reﬂexes. Question 7: TTTFF Postherpetic neuralgia (PHN) is the term used to describe the painful aftermath of herpes zoster (HZ) infection, also known as shingles. The diagnosis is given to patients who still have pain three months or more following HZ. It is the reactivation of varicella zoster virus (VZV) that gives rise to HZ and it remains in a latent state in spinal and cranial sensory ganglia until reactivation. Although most people are immune due to childhood vaccination or exposure to wild-type virus, immunity may be decreased – by disease or immune suppression – and reactivation occur. 428 Chapter 5b: Clinical Anaesthesia Answers Risk factors include: Older age (it is rare below 50 years) Female sex Acute pain and rash severity Dermatomal pain before rash appears Most patients experience a painful vesicular eruption in a single dermatome that settles within three months. However, approximately 20% will develop PHN. The pain is intense and described as burning, throbbing, stabbing or shooting. It can be continuous or inter- mittent, and patients often experience allodynia and hypersensitivity. The pain can be very debilitating and lead to depression and social isolation. Question 8: TFFFF Some measures that are part of good intensive care practice also apply to the management of the potential heart-beating donor, but there are additional measures shown to increase the viability and number of transplantable organs. Endocrine dysfunction following brainstem death can contribute to organ failure and hence hormone replacement may help preserve homeostasis. The hormones commonly replaced are insulin, methylprednisolone and triiodothyronine. The rationale for using these hormones is: insulin for treating hyperglycaemia, methylprednisolone to counter the cytokine-driven inﬂammatory response and thyroid hormones to improve the function of transplanted hearts in the recipient. Donor lungs are susceptible to ﬂuid overload and so considerations may include the measurement of left-sided ﬁlling pressures and avoiding a CVP of >6 mmHg (without PEEP), which may worsen the alveolar–arterial oxygen gradient. The use of lung protective ventilation, including a positive end expiratory pressure of 5–10 cmH2O, can be eﬀective in treating pulmonary oedema and preventing alveolar collapse. Hypotension is initially managed with volume loading because potential donors often are often relatively vasodilated, but where vasopressor support is required vasopressin is the ﬁrst-line agent. In septic patients doses of vasopressin >2.5 U.h−1 are associated with adverse outcomes, including cardiac arrest. Question 9: FFTTF The Rule of Nines is a quick method used to estimate medium to large-sized burns in adults (it is not accurate in children). The body is divided into areas of 9% TBSA (see Table 5.9.1). Table 5.9.1 Head (front and back) = 9% Anterior chest = 18% Back = 18% Each arm = 9% Each leg = 18% Perineum = 1% Chapter 5b: Clinical Anaesthesia Answers 429 For small burns (generally < 5% TBSA) the palmer surface method can be used. In this method the surface of the patient’s palm, including the ﬁngers, is estimated to be approximately 0.8–1% of TBSA and can be used to estimate the burn area. Question 10: TFFTF Bariatric surgery has been sanctioned by NICE as a recommended treatment for obesity, and has been shown to cause a maintainable reduction in weight of more than 50% in some cases. Laparoscopic techniques have a lower morbidity and mortality in the short term; this is thought to be due to diﬀerences in wound healing and postoperative pain causing problems with respiratory function. According to studies by Brodsky et al., raised BMI in isolation is not an indicator of diﬃcult intubation, but raised BMI with other signs such as a Mallampati score of >3 is an indication of a potentially diﬃcult airway. The incidence of OSA in obese patients is approximately 5%, but a history of daytime somnolence, apnoeic periods or snoring should be sought, as preoperative CPAP/BiPAP may be helpful. Due to excess limb weight and positioning, nerve injuries are more common in the obese. Suxamethonium dose should be based upon actual body weight due to increased plasma cholinesterase activity. Question 11: TTTFF RCOA guidelines require a number of features speciﬁc to paediatric day surgery. A PICU on site is not essential unless infants with chronic lung disease are undergoing surgery. Ex- premature neonates should not undergo day-case anaesthesia unless over 60 weeks post conception and medically ﬁt. Play specialists are not obligatory, but suitable paediatric facilities must be available. Question 12: FTFTT There are several bedside tests that may predict diﬃcult intubation: The inability to protrude the mandibular incisors A sternomental distance less than 12 cm A thyromental distance less than 6 cm Mallampati score 3 or 4 The presence of buck teeth Limited ability to extend the neck Previous radiotherapy to the head and neck can cause formation of ﬁbrotic tissue and reduced mobility of tissues, causing diﬃculty at intubation. Previous tracheostomy forma- tion or prolonged intubation may result in scarring and tracheal stenosis. The presence of numerous congenital syndromes, including Pierre Robin, Treacher Collins and Goldenhar syndrome, plus mucopolysaccharide disorders such as Hurler’s and Hunter’s syndromes, are associated with diﬃcult intubation. The presence of a high- arched palate is seen in Marfan’s and Down’s syndromes and may complicate intubation. Question 13: TFFTF Thoracic paravertebral blocks provide an ipsilateral somatic and sympathetic nerve block similar to a unilateral epidural block, especially useful for breast surgery, thoracotomy, in 430 Chapter 5b: Clinical Anaesthesia Answers patients with rib fractures or open cholecystectomy. The thoracic paravertebral space is a wedge-shaped area that lies on either side of the vertebral column deﬁned by: Parietal pleura anterolaterally The vertebral body, intervertebral disc and intervertebral foramen medially The superior costotransverse ligament posteriorly The space is continuous with the intercostal space laterally, epidural space medially and contralateral paravertebral space via the prevertebral fascia. As the nerves emerge from intervertebral foramina, they transverse through the paravertebral space where they may be blocked by local anaesthetics, thereby blocking dorsal and ventral rami and hence the sympathetic chain. The block can be inserted with ultrasound guidance, but more commonly is performed using a landmark technique. C7 is the most prominent cervical spinous process, whilst the lower tip of the scapula lines up with T7. Complications of paravertebral blocks include infection, haematoma, local anaesthetic toxicity, nerve injury and, rarely, total spinal anaesthesia and paravertebral muscle pain (resembling muscle spasm mainly in young muscular men, especially when larger gauge Tuohy needles are used). Question 14: FFTTF There is no good evidence to support one inotrope over another in cardiogenic shock. Dobutamine is used frequently, not only because of its positive inotropic eﬀect, but also as a peripheral vasodilator, reducing the afterload against a failing heart. In this case the BP is signiﬁcantly low and will be made worse by dobutamine. Adrenaline is a potent vasopressor through its action on the α1-receptor, which will support the SVR in this situation. In diastolic dysfunction the cardiac output is dependent on venous return and ﬁlling pressure, which will be reduced by dobutamine due to vasodilatation. IABP can be quite helpful in patients with ischaemic cardiogenic shock who are expected to be on multiple inotropes. It will improve the coronary perfusion during diastole and reduce the afterload during systole. Noradrenaline is not routinely used as a ﬁrst-line agent in these cases. Raised lactate in this case is due to pump failure that is unlikely to be helped by noradrenaline. However, it can be added later on if the low BP proved to be resistant to either adrenaline or dopamine as a single agent. Question 15: TFFTT Acute fatty liver of pregnancy is a serious condition aﬀecting approximately 5 in every 100 000 pregnancies and has a signiﬁcant maternal mortality and morbidity. The maternal mortality rate is now in the region of 10–20%, having been over 85% when the disease was ﬁrst identiﬁed. It often presents later in pregnancy (after 30 weeks). Common signs and symptoms include jaundice, abdominal pain, altered mental state, nausea and acute renal impairment. The features of pre-eclampsia are present in a signiﬁcant proportion of patients and it can be diﬃcult to diﬀerentiate clinically and biochemically from HELLP syndrome. There is a higher incidence of AFLP in ﬁrst pregnancies, multiple pregnancies and when the fetus is male (3:1 M:F). Radiological appearances can be normal and liver biopsy remains the gold standard test; it is, however, often contraindicated due to an underlying coagulopathy. There are risks and beneﬁts of both general and regional Chapter 5b: Clinical Anaesthesia Answers 431 anaesthesia and both have been used safely, provided none of the usual contraindications are present. Question 16: FFTTF CPET is a very useful test in assessing patients for lung resection. It is not needed for all patients. In those patients with poor predicted lung function as well as unexplained poor functional capacity it is indicated. If the peak VO2 is above 20 ml.kg–1.min–1 they can usually have resection up to pneumonectomy. The ability to climb two ﬂights correlates with a VO2 max of approximately 12 ml.kg–1.min–1. The anaerobic threshold is approximately 55% of VO2 max in untrained individuals but rises to >80% in trained athletes. Question 17: FTTFT Sickle cell disease is an inherited haemoglobinopathy resulting from a mutation on chro- mosome 11. The mutation causes a pathological amino-acid substitution of valine for glutamic acid on the β-globin chain of haemoglobin A. This substitution produces haemo- globin S, which is inherently unstable and can adopt the notorious ‘sickle’ appearance under ® certain conditions. The Sickledex test is a sickle solubility test and is used in emergency situations as a rapid screening test. It detects haemoglobin S levels greater then 10%, but is unable to diﬀerentiate between homozygous (sickle cell disease) and heterozygous (sickle cell trait) conditions. Haemoglobin electrophoresis is the deﬁnite distinguishing test. Sickle cell trait has been shown in numerous studies to confer strong protection against Plasmodium falciparum malaria. The protective mechanisms are not fully understood. However, proposed mechanisms include a reduction in parasite growth and enhanced removal of parasitized cells through acquired or innate immune systems. Question 18: FTFTT The tongue is large and the larynx is situated more anteriorly and cephalad (C3–C4). The epiglottis is large and U-shaped. The cricoid cartilage is the narrowest part of the upper airway and a small decrease in diameter caused by oedema or stricture formation following prolonged tracheal intubation may lead to airway obstruction. Tidal volume is ﬁxed and ventilatory frequency needs to be increased to increase minute ventilation. Ventilation is mainly diaphragmatic and there are fewer type I muscle ﬁbres, so infants fatigue earlier. FRC is less than the closing capacity owing to the low elastic recoil of the chest wall. This, along with the high metabolic requirement, predisposes them to hypoxia. Question 19: FFTFF Recognition of malignant hyperpyrexia (MH) is key: the AAGBI guidance from 2011 suggests unexplained increase in heart rate and end tidal CO2, alongside increased oxygen requirement, and possibly late-onset temperature rises, should prompt recognition of MH. Volatile anaesthesia should be discontinued and anaesthesia maintained via intravenous agents. The patient should be ventilated with 100% oxygen via a clean circuit and preferably via a dedicated anaesthetic machine that has not been in contact with volatile anaesthetic agents. While hyperventilation may help control respiratory acidosis, it alone is not 432 Chapter 5b: Clinical Anaesthesia Answers adequate management. Close liaison with the surgical team is vital – explain that there is an anaesthetic emergency and that completion of surgery should be expedited, or, if feasible, surgery abandoned. In this case, conversion to an open procedure may be warranted depending on surgical experience/expertise. The recommended bolus dose is now 2.5 mg.kg–1 of dantrolene with further 1 mg.kg–1 boluses up to 10 mg.kg–1. Active cooling measures need to be taken, but using ice is likely to cause peripheral vasoconstriction that is counterproductive and should be avoided. Question 20: TTFTT Risk factors can be split into a number of categories: Delayed gastric emptying (pain, trauma, opioids, alcohol) Medical conditions (GORD, hiatus hernia, diabetic neuropathy, neurological/ neuromuscular disease) Acute illness (bowel obstruction/ileus, metabolic derangement, impaired consciousness) Question 21: TFTFF In 2015/16, 33% of renal transplants in the UK were from living donors. Under UK guidelines both a consultant surgeon and consultant anaesthetist should be present during the donor nephrectomy. As long as the renal function tests and urine production are normal, hypertension is not a contraindication to being a living donor. Diabetes mellitus is a contraindication to donating, but those with impaired glucose tolerance may be considered if fasting glucose is 6 years, pyridostigmine dose >750 mg.day–1, preoperative vital capacity of 90% but it is now thought to be nearer to 50% for a single procedure. Question 297: TTTTT In Addison’s disease there is destruction of the adrenal cortex, resulting in decreased or absent secretion of glucocorticoids and decreased secretion of mineralocorticoi

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