Essential clinical anesthesia review keywords, questions and answers for the boards

sách y khoa tiếng anh dành cho chuyên khoa gây mê hồi sức bản update 2016. Nội dung dễ hiểu, thiết thực. sách y khoa tiếng anh dành cho chuyên khoa gây mê hồi sức bản update 2016. Nội dung dễ hiểu, thiết thực.sách y khoa tiếng anh dành cho chuyên khoa gây mê hồi sức bản update 2016. Nội dung dễ hiểu, thiết thực.

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Essential Clinical Anesthesia Review: Keywords, Questions and Answers for the Boards

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University Printing House, Cambridge CB2 8BS, United Kingdom 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 national levels of excellence.

inter-www.cambridge.org

Information on this title: www.cambridge.org/9781107681309

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 2015

Printed in the United Kingdom by Clays, St Ives plc

A catalogue record for this publication is available from the British Library Library of Congress Cataloguing in Publication data

Essential clinical anesthesia review : keywords, questions and answers for the boards / edited by Linda S Aglio, Robert W Lekowski, Richard D Urman.

p ; cm.

Includes bibliographical references and index.

ISBN 978-1-107-68130-9 (Hardback)

I Aglio, Linda S., editor II Lekowski, Robert W., editor.

III Urman, Richard D., editor.

[DNLM: 1 Anesthesia –Examination Questions 2 Anesthesia– Outlines 3 Anesthetics –administration & dosage–Examination Questions 4 Anesthetics –administration & dosage–Outlines.

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List of contributors xi

Preface xvii

History of anesthesia 1

Manisha S Desai and Sukumar P Desai

evaluation

1 Preoperative anesthetic assessment 3

Emily L Wang and Jeffrey Lu

2 Obstructive and restrictive lung disease 8

3 Anesthetic goals in patients with myocardial

ischemia and heart failure 15

Thomas Hickey and Linda S Aglio

4 Anesthetic goals in patients with valvular heart

disease 18

Zahra M Malik and Martin Zammert

5 Obesity 22

Kelly G Elterman and Suzanne Klainer

6 Chronic renal failure 26

Michael Vaninetti and Assia Valovska

7 Liver disease 30

Julia Serber and Evan Blaney

8 Principles of diabetes mellitus and perioperative

glucose control 33

Olutoyin Okanlawon and Richard D Urman

9 Common blood disorders 37

Rosemary Uzomba, Michael D’Ambra, and Robert

W Lekowski

10 The elderly patient 43

Allison Clark and Lisa Crossley

11 Neurologic diseases and anesthesia 45

Nantthasorn Zinboonyahgoon and Joseph

M Garfield

12 Anesthetic considerations in psychiatric disease 51

Nantthasorn Zinboonyahgoon and Joseph M Garfield

13 Substance abuse and anesthesia 56

14 Anatomy of the human airway 61

Richard Hsu and Christopher Chen

15 Airway assessment 64

16 Perioperative airway management 67

Richard Hsu and Maksim Zayaruzny

17 Management of the difficult airway 70

18 Medical gas supply, vacuum, and scavenging 74

Marc Philip T Pimentel and James H Philip

19 Anesthesia machine 76

20 Anesthesia ventilators 79

21 Anesthesia breathing apparatuses 82

22 Electrical safety 85

23 Hemodynamic patient monitoring 88

24 The electrocardiogram and approach to diagnosis

of common abnormalities 93

25 Pulse oximetry and capnography 101

Hanjo Ko and George P Topulos

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26 Monitoring of neuromuscular blockade 104

M Tariq Hanifi, J Matthew Kynes, and Joseph M Garfield

27 Thermoregulation and temperature monitoring 107

Jessica Bauerle and Zhiling Xiong

28 Neurophysiologic monitoring 109

Scott W Vaughan and Linda S Aglio

29 Intraoperative awareness 113

30 Inhalation anesthetics 115

Carly C Guthrie and Jeffrey Lu

31 Pharmacokinetics of inhalation agents 118

32 Pharmacodynamics of inhalation agents 121

and adjunct drugs

33 Intravenous induction agents 124

Lisa M Hammond and James Hardy

34 Mechanisms of anesthetic actions 127

35 Pharmacokinetics of intravenous agents 130

Alissa Sodickson and Richard D Urman

36 Opioids 133

37 Muscle relaxants 137

M Tariq Hanifi and Michael Nguyen

38 Reversal of neuromuscular blockade 140

39 Perioperative pulmonary aspiration prophylaxis 143

40 Perioperative antiemetic therapies 147

Iuliu Fat and Devon Flaherty

41 COX inhibitors and alpha2-adrenergic agonists 149

anesthetics

45 Pharmacology of local anesthetics: mechanism ofaction and pharmacokinetics 159

Jessica Bauerle and Zhiling Xiong

46 Clinical applications of local anesthetics 161

47 Administration of general anesthesia 164

48 Total intravenous anesthesia 166

49 Monitored anesthesia care 169

50 Patient positioning and common nerve injuries 172

J Matthew Kynes and Joseph M Garfield

from anesthesia

51 Emergence from anesthesia 174

Pete Pelletier and Galina Davidyuk

52 Postoperative complications in the post-anesthesiacare unit 177

Pete Pelletier and Galina Davidyuk

53 Management of postoperative nausea andvomiting 179

54 Cognitive changes after surgery and anesthesia 181

55 Anatomy of the vertebral column and spinal cord 183

Jennifer Oliver and Jose Luis Zeballos

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58 Principles of ultrasound-guided nerve blocks 192

Rejean Gareau and Kamen Vlassakov

59 Upper extremity nerve blocks 194

60 Lower extremity nerve blocks 197

61 Fluid replacement 202

Pingping Song and Gyorgy Frendl

62 Acid–base balance in anesthesia and intensive

care medicine 205

63 Ion balance 209

64 Total parenteral nutrition 214

Hanjo Ko and Robert W Lekowski

68 Normovolemic hemodilution, perioperative blood

salvage, and autologous blood donation 224

69 Cardiac physiology 225

Erich N Marks and Lauren J Cornella

70 Cardiovascular pharmacology 230

71 Adjunct cardiovascular drugs 238

72 Coronary artery bypass grafting utilizing

cardiopulmonary bypass 241

73 Off-pump coronary artery bypass 244

74 Transesophageal echocardiography 246

75 Pacemakers and automated implantablecardioverter-defibrillators 249

Jessica Patterson and John A Fox

76 Ventricular assist devices 252

77 Anesthetic considerations for surgical repair

of the thoracic aorta 254

78 Cardiac transplantation in the adult 257

79 Persistent postoperative bleeding in cardiacsurgical patients 259

Rosemary Uzomba, Michael D’Ambra, and Robert

W Lekowski

80 Carotid endarterectomy 265

Agnieszka Trzcinka and Shaheen Shaikh

81 Abdominal aortic aneurysm 267

Mohab Ibrahim and Linda S Aglio

82 Endovascular abdominal aortic aneurysm repair 270

Andrea Girnius and Annette Mizuguchi

83 Peripheral vascular disease 272

84 Respiratory physiology 274

85 Oxygen and carbon dioxide transport 277

86 Lung isolation techniques 279

Yuka Kiyota, Philip M Hartigan, andGeorge P Topulos

87 Anesthetic management for pulmonaryresection 282

Yuka Kiyota, George P Topulos, andPhilip M Hartigan

88 Lung transplantation for end-stage lung disease 286

Stephanie Yacoubian and Ju-Mei Ng

89 Bronchoscopy and mediastinoscopy: anestheticimplications 291

90 Management of mediastinal mass 295

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95 Anesthesia for electroconvulsive therapy 311

urinary tract diseases

96 Renal physiology 314

97 Urology 316

98 Kidney and pancreas transplantation 319

procedures

99 Anesthesia for intra-abdominal surgery 322

100 Principles of laparoscopic surgery 325

101 Principles of anesthesia for esophageal and gastric

surgery 328

102 Principles of anesthesia for breast and gynecologic

surgery 331

103 Anesthesia for liver transplantation 334

diseases

104 Thyroid disorders 336

Hyung Sun Choi and Vesela Kovacheva

105 Parathyroid disorders 339

106 Pheochromocytoma and carcinoid tumors 342

107 Syndrome of inappropriate antidiuretic hormone,diabetes insipidus, and transsphenoidal pituitarysurgery 345

Syed Irfan Qasim Ali and Vesela Kovacheva

108 Disorders of the adrenal cortex 348

Syed Irfan Qasim Ali and Vesela Kovacheva

and collagen disease

109 Malignant hyperthermia 351

Zinaida Chepurny and Alvaro A Macias

110 Myasthenia gravis 354

111 Muscular dystrophy and myotonic dystrophy 357

and throat diseases

112 Ophthalmic procedures 360

Caryn Barnet and Dongdong Yao

113 Common otolaryngology procedures 362

114 Lasers, airway surgery, and operatingroom fires 364

and trauma surgery

115 Anesthesia for common orthopedic procedures 367

Christopher Voscopoulos and David Janfaza

116 Rheumatoid arthritis and scoliosis 372

117 Anesthetic management in spine surgery 375

118 Anesthesia for trauma 378

Contents

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Section 23 – Obstetric anesthesia

119 Physiologic changes during pregnancy 382

Brendan McGinn and Jie Zhou

120 Analgesia for labor 385

121 Anesthesia for cesarean delivery 388

122 Obstetric hemorrhage 390

Benjamin Kloesel and Michaela K Farber

123 Preeclampsia 393

124 Pregnant patients with comorbid diseases 396

125 Anesthesia for fetal intervention 399

126 Basic considerations for pediatric anesthesia 401

Laura Westfall and Susan L Sager

127 Preoperative evaluation of the pediatric patient

and coexisting diseases 405

128 Anesthetic considerations for common

procedures in children 408

129 Neonatal surgical emergencies 411

Jonathan R Meserve and Susan L Sager

130 Congenital heart disease 414

131 Management of postoperative pain in children 417

132 Neonatal resuscitation: clinical and practical

considerations 420

location anesthesia

133 Introduction to ambulatory anesthesia 423

Jonathan R Meserve and Richard D Urman

134 Anesthesia outside the operating room 425

135 Office-based anesthesia 427

anesthesia practice

136 Patient safety, quality assurance, and riskmanagement 429

Jaida Fitzgerald and Robert W Lekowski

137 Operating room management: core principles 431

138 Practice management 433

139 Principles of medical ethics 435

Christian Peccora and Richard D Urman

140 Risks in the operating room 438

141 Statistics for anesthesiologists and researchers 441

142 Neurophysiology of pain 444

Christian Peccora and Jie Zhou

143 Postoperative acute pain management 448

Christian Peccora and Jie Zhou

144 Multidisciplinary approach to chronic painmanagement 453

Cyrus Ahmadi Yazdi and Srdjan S Nedeljkovic

145 Psychological evaluation and management ofpatients with chronic pain 455

146 Interventional pain management I:

Epidural, sympathetic, and neural blockadeprocedures 457

147 Interventional pain management II: Implantableand other invasive therapies 460

148 Complications associated with interventions

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150 Complex regional pain syndrome 467

J Tasker Gundy and Elizabeth M Rickerson

151 Cancer pain 469

J Tasker Gundy and Elizabeth M Rickerson

152 Cardiopulmonary resuscitation 472

Christopher Voscopoulos and Joshua Vacanti

153 Multiorgan failure and its prevention 477

Timothy D Quinn and Sujatha Pentakota

154 Supraventricular arrhythmias 480

Timothy D Quinn and Sujatha Pentakota

155 Cardiac failure in the intensive care unit 483

Krishna Parekh and David Silver

156 Sedation in the surgical intensive care unit 485

Krishna Parekh and David Silver

157 Weaning from mechanical ventilation 487

158 Acute lung injury and acute respiratory distress

syndrome 490

Beverly Chang and Gyorgy Frendl

159 Nosocomial infections 494

160 Septic shock and sepsis syndromes 499

161 Anesthetic management of the brain-dead organ

donor 504

162 Principles of trauma management 506

163 Venous thromboembolic disease in the critically

ill patient 508

164 Traumatic brain injury 510

Whitney de Luna and Linda S Aglio

165 Burn management 513

166 Common ethical issues in the intensive care

unit 516

167 Bronchopleural fistula 518

Yuka Kiyota, George P Topulos, and Philip M Hartigan

168 Inhaled nitric oxide 520

Yuka Kiyota and Stanton Shernan

169 Skin and collagen disorders 521

170 Anesthesia for aesthetic surgery 523

171 Intra-abdominal hypertension and abdominalcompartment syndrome 525

172 Carbon monoxide and cyanide poisoning 528

173 Chemical and biologic warfare agents: anintroduction for anesthesiologists 531

Joyce Lo and Laverne D Gugino

174 Anesthesia for robotic surgery 534

Michael Vaninetti, Joyce Lo, and Assia Valovska

175 Human immunodeficiency virus, methicillin-resistantStaphylococcus aureus, and vancomycin-resistantEnterococcus 537

176 Alternative medicines and anesthesia 539

Syed Irfan Qasim Ali and Richard D Urman

177 Anesthesia in high altitudes 542

Stephanie Yacoubian, Syed Irfan Qasim Ali, FelicityBillings, and Richard D Urman

178 Medical informatics and information managementsystems in anesthesia 545

Syed Irfan Qasim Ali and Richard D Urman

179 Hypertrophic cardiomyopathy and prolonged

QT interval 547

Index 549Contents

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and Pain Medicine

Brigham and Women’s Hospital, Boston, MA, USA

Galina Davidyuk, MD PhD

Instructor of Anaesthesia, Harvard Medical School

Anesthesiologist, Department of Anesthesiology, Perioperative

and Pain Medicine

Clinical Associate Professor of Anesthesiology

University of Massachusetts School of Medicine

Worcester, MA, USA

Sukumar P Desai, MD

Assistant Professor of Anaesthesia, Harvard Medical School

and Pain Medicine

Kelly G Elterman, MD

Clinical Fellow of Anaesthesia, Harvard Medical School

Resident, Department of Anesthesiology, Perioperative and

Pain Medicine

Michaela K Farber, MD MS

and Pain Medicine

Iuliu Fat, MD PhD FRCP

Pain Medicine

Jaida Fitzgerald, MD

Pain Medicine

Devon Flaherty, MD MPH

and Pain Medicine

John A Fox, MD

and Pain MedicineBrigham and Women’s Hospital, Boston, MA, USAGyorgy Frendl, MD PhD

Associate Professor of Anaesthesia, Harvard Medical SchoolAnesthesiologist, Department of Anesthesiology, Perioperativeand Pain Medicine

Brigham and Women’s Hospital, Boston, MA, USARejean Gareau, MD FRCP(C)

Clinical Fellow of Anaesthesia, Harvard Medical SchoolResident, Department of Anesthesiology, Perioperative andPain Medicine

Brigham and Women’s Hospital, Boston, MA, USAJoseph M Garfield, MD

Associate Professor of Anaesthesia, Harvard Medical SchoolAnesthesiologist, Department of Anesthesiology, Perioperativeand Pain Medicine

Brigham and Women’s Hospital, Boston, MA, USAAndrea Girnius, MD

Brigham and Women’s Hospital, Boston, MA, USALaverne D Gugino, MD PhD

Associate Professor of Anaesthesia, Harvard Medical SchoolDirector of Intraoperative Neurophysiological MonitoringDepartment of Anesthesiology, Perioperative and PainMedicine

J Tasker Gundy, MDClinical Fellow of Anaesthesia, Harvard Medical SchoolResident, Department of Anesthesiology, Perioperative andPain Medicine

Brigham and Women’s Hospital, Boston, MA, USACarly C Guthrie, MD

Brigham and Women’s Hospital, Boston, MA, USALisa M Hammond, MD

M Tariq Hanifi, MDClinical Fellow of Anaesthesia, Harvard Medical SchoolResident, Department of Anesthesiology, Perioperative andPain Medicine

List of contributors

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James Hardy, MB BS

and Pain Medicine

Philip M Hartigan, MD

Director of Thoracic Anesthesia

Department of Anesthesiology, Perioperative and Pain Medicine

Thomas Hickey, MD MS

Pain Medicine

Richard Hsu, MD

Pain Medicine

Mohab Ibrahim, MD PhD

Assistant Professor of Anesthesiology and Pharmacology,

University of Arizona Medical School

Director of the Pain Clinic, University of Arizona Medical

Center, Tucson, AZ, USA

David Janfaza, MD

and Pain Medicine

Yuka Kiyota, MD MPH

Pain Medicine

Suzanne Klainer, MD

and Pain Medicine

Benjamin Kloesel, MD MSBS

Pain Medicine

Hanjo Ko, MD MSc

Pain MedicineBrigham and Women’s Hospital, Boston, MA, USABhavani Kodali, MD

Associate Professor of Anaesthesia, Harvard Medical SchoolVice Chair of Clinical Affairs

Department of Anesthesiology, Perioperative and Pain MedicineBrigham and Women’s Hospital, Boston, MA, USA

Vesela Kovacheva, MD PhDInstructor of Anaesthesia, Harvard Medical SchoolAnesthesiologist, Department of Anesthesiology,Perioperative and Pain Medicine

J Matthew Kynes, MDClinical Fellow of Anaesthesia, Harvard Medical SchoolResident, Department of Anesthesiology, Perioperative andPain Medicine

Brigham and Women’s Hospital, Boston, MA, USARobert W Lekowski, MD

Residency Program Director at the Department ofAnesthesiology, Perioperative and Pain Medicine, Brighamand Women’s Hospital and Assistant Professor of Anesthesia,Harvard Medical School, Boston, MA, USA

Joyce Lo, MDClinical Fellow of Anaesthesia, Harvard Medical SchoolResident, Department of Anesthesiology, Perioperative andPain Medicine

Brigham and Women’s Hospital, Boston, MA, USAJeffrey Lu, MD

Instructor of Anaesthesia, Harvard Medical SchoolAnesthesiologist, Department of Anesthesiology, Perioperativeand Pain Medicine

Brigham and Women’s Hospital, Boston, MA, USAAlvaro A Macias, MD

Brigham and Women’s Hospital, Boston, MA, USAZahra M Malik, MD

Brigham and Women’s Hospital, Boston, MA, USAErich N Marks, MD

Assistant Professor at the Department of Anesthesiology,University of Wisconsin, Madison, WI, USA

Brendan McGinn, MDClinical Fellow of Anaesthesia, Harvard Medical SchoolResident, Department of Anesthesiology, Perioperative and

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Pain Medicine

Jonathan R Meserve, MD

Pain Medicine

Annette Mizuguchi, MD

and Pain Medicine

Srdjan S Nedeljkovic, MD

and Pain Medicine

Fellowship Director, Pain Medicine

Ju-Mei Ng

and Pain Medicine

Michael Nguyen, MD

and Pain Medicine

Olutoyin Okanlawon, MD MPH

Pain Medicine

Jennifer Oliver, DO MPH

Pain Medicine

Krishna Parekh, MD

Pain Medicine

Jessica Patterson, MD

Pain Medicine

Christian Peccora, MDClinical Fellow of Anaesthesia, Harvard Medical SchoolResident, Department of Anesthesiology, Perioperative andPain Medicine

Brigham and Women’s Hospital, Boston, MA, USAPete Pelletier, MD

Brigham and Women’s Hospital, Boston, MA, USASujatha Pentakota, MD

Brigham and Women’s Hospital, Boston, MA, USAJames H Philip, ME(E) MD

Professor of Anaesthesia, Harvard Medical SchoolAnesthesiologist and Director of Clinical BioengineeringDepartment of Anesthesiology, Perioperative and PainMedicine

Brigham and Women’s Hospital, Boston, MA, USAMarc Philip T Pimentel, MD

Brigham and Women’s Hospital, Boston, MA, USATimothy D Quinn, MD

Brigham and Women’s Hospital, Boston, MA, USAElizabeth M Rickerson, MD

Brigham and Women’s Hospital, Boston, MA, USAPalliative Care Physician, Department of PsychosocialOncology and Palliative Care

Dana Farber Cancer Institute, Boston, MA, USASusan L Sager, MD

Boston Children’s Hospital, Boston, MA, USAJulia Serber, MD

Clinical Fellow of Anaesthesia, Harvard Medical SchoolResident, Department of Anesthesiology, Perioperative andPain Medicine, Brigham and Women’s Hospital, Boston,

MA, USA

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Shaheen Shaikh, MD

Assistant Professor of Anaesthesia

University of Massachusetts Medical School

Director of Neuroanesthesia

University of Massachusetts Medical Center, Worcester, MA, USA

Stanton Shernan, MD

Professor of Anaesthesia, Harvard Medical School

Director of Cardiac Anesthesia, Department of Anesthesiology,

Perioperative and Pain Medicine Brigham and Women’s

Hospital, Boston, MA, USA

David Silver, MD

Associate Professor of Anaesthesia, Harvard Medical School

and Pain Medicine

Alissa Sodickson, MD

Pain Medicine

Pingping Song, MD

Pain Medicine

George P Topulos, MD

Associate Professor of Anaesthesia, Harvard Medical School

and Pain Medicine

Agnieszka Trzcinka, MD

Pain Medicine

Richard D Urman, MD MBA CPE

Medical Director of Procedural Sedation at the Brigham and

Women’s Hospital, Co-Director of the Center for

Perioperative Management and Medical Informatics, and

Assistant Professor of Anesthesia at Harvard Medical School,

Boston, MA, USA

Rosemary Uzomba, MD

Pain Medicine

Joshua Vacanti, MD

and Pain MedicineBrigham and Women’s Hospital, Boston, MA, USAAssia Valovska, MD

Brigham and Women’s Hospital, Boston, MA, USAMichael Vaninetti, MD

Brigham and Women’s Hospital, Boston, MA, USAScott W Vaughan, DO

Brigham and Women’s Hospital, Boston, MA, USAKamen Vlassakov, DO

Assistant Professor of Anaesthesia, Harvard Medical SchoolDirector of Orthopedic Anesthesia

Anesthesiologist, Department of Anesthesiology, Perioperativeand Pain Medicine

Brigham and Women’s Hospital, Boston, MA, USAChristopher Voscopoulos, MD

Brigham and Women’s Hospital, Boston, MA, USAEmily L Wang, MD

Brigham and Women’s Hospital, Boston, MA, USALaura Westfall, MD

Brigham and Women’s Hospital, Boston, MA, USAZhiling Xiong, MD PhD

Assistant Professor of Anaesthesia, Harvard Medical SchoolDirector of General Surgery Anesthesia, Department ofAnesthesiology, Perioperative and Pain Medicine, Brighamand Women’s Hospital, Boston, MA, USA

Stephanie Yacoubian, MDClinical Fellow of Anaesthesia, Harvard Medical SchoolResident, Department of Anesthesiology, Perioperative andPain Medicine

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Dongdong Yao, MD PhD

and Pain Medicine

Martin Zammert, MD

Director of Vascular Anesthesia, Department of

Anesthesiology, Perioperative and Pain Medicine, Brigham

and Women’s Hospital, Boston, MA, USA

Maksim Zayaruzny, MD

Assistant Professor of Anaesthesia, University of

Massachusetts Medical School

Anesthesiologist, University of Massachusetts Medical Center,

Worcester, MA, USA

Jose Luis Zeballos, MDInstructor of Anaesthesia, Harvard Medical SchoolAnesthesiologist, Department of Anesthesiology, Perioperativeand Pain Medicine

Brigham and Women’s Hospital, Boston, MA, USANatthasorn Zinboonyahgoon, MD

Brigham and Women’s Hospital, Boston, MA, USAJie Zhou, MD MS MBA

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Significant advances in basic science and the clinical practice of

anesthesiology over the past decade have contributed

exponen-tially to our specialty and necessitated the writing of this book

Our aim has been to provide a comprehensive and readily

available reference and training source, prepared by a team

of experts in their field, to clarify the basics of anesthetic

management, including all new guidelines and recently

developed standards of care

Essential Clinical Anesthesia Review: Keywords, Questions

and Answers for the Boards is the first review book of its kind

published to serve as a companion for the written and

re-certification board examinations, based on Essential Clinical

Anesthesia and other authoritative sources

In addition, it presents a group of important clinical entities

covering critical anesthetic scenarios It is an invaluable resource

to any practicing anesthesia provider looking for an up-to-date

review of problem-oriented patient management issues

The material in this book will serve a wide range of learners

and practitioners: medical students during their anesthesia

rotation; residents and fellows studying for ABA (American

Board of Anesthesiology) boards; student nurse anesthetistsand certified registered nurse anesthetists (CRNAs); and prac-ticing physicians It will also serve as a source of review for thecontinuing education and ABA re-certification for the prac-ticing anesthesiologist

This book is organized into 29 sections and reflects thecontent of Essential Clinical Anesthesia and other CambridgeUniversity Press resources Each section has several chaptersorganized according to the ABA keyword list for a particularproblem or clinical case scenario The keyword list isfollowed by a concise discussion that includes preoperativeassessment, intraoperative management, and postoperativepain management

The book is designed to emphasize the fundamentalconcepts or keywords that are required to pass an exam andgives the reader the opportunity to see the application of theseconcepts in everyday practice The text reflects the opinionsand the clinical experiences of anesthesia experts at HarvardMedical School as well as individually known national experts

in the field of anesthesiology

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History of anesthesia Manisha S Desai and Sukumar P Desai

Although anesthetic properties of nitrous oxide and ether were

discovered in the 1800s, surgical operations were likely carried

out under varied degrees of analgesia from times immemorial

Opiates, alcohol, cannabinoids, belladona derivatives, soporific

sponges, and mesmerism were used to offer relief during

surgery and are a testament to man’s ingenuity

Joseph Priestley (1733–1804, UK) discovered oxygen in

1771, and nitrous oxide in 1772 Humphry Davy (1778–1829,

UK) discovered the analgesic properties of nitrous oxide in

1800 and termed it“laughing gas”; however, he did not use it

in any clinical setting In the United States, recreational use

of ether and nitrous oxide was common in the 1840s

(ether frolics and laughing gas parties) William E Clarke

(1819–1898, USA), while a medical student, was the first to

administer ether for dental extraction in January 1842 On

March 30, 1842, Crawford W Long (1815–1878, USA)

admin-istered ether to James Venable during removal of a tumor

from his back Long continued using ether during surgery,

but did not publish his findings until 1849 During an evening

of public entertainment in 1844, Gardner Quincy Colton

(1814–1898, USA) administered nitrous oxide to Samuel

A Cooley Cooley injured himself as he was returning to his

seat but did not feel any pain for a few minutes Horace Wells

(1815–1848, USA) attended the same demonstration and

believed this was due to the analgesic effects of nitrous oxide

The next morning, fellow dentist John M Riggs (1811–1885,

USA) removed one of Wells’ teeth painlessly while Colton

administered nitrous oxide Wells used nitrous oxide for pain

relief in his own dental practice, but when he attempted to

demonstrate this effect at Massachusetts General Hospital in

1845, the subject cried out in pain during the procedure,

although later admitting that he did not remember any pain

However, Wells’ reputation never recovered from this ent fiasco, and his life ended tragically in 1848 WilliamThomas Green Morton (1819–1868, USA), an associate ofWells, was present during the failed demonstration Heconsulted with Harvard professor Charles T Jackson(1805–1880, USA) and conducted experiments with ether

appar-On October 16, 1846 Morton performed the first successfulpublic demonstration of ether anesthesia while surgeon JohnCollins Warren (1778–1856, USA) removed a vascular tumorfrom the neck of Edward Gilbert Abbott October 16 hasthereafter been celebrated as Ether Day, and the amphitheater

in which the procedure took place, Ether Dome, has beenpreserved as a museum at Massachusetts General Hospital,Boston

News about the anesthetic properties of ether and nitrousoxide spread rapidly, and other agents were investigated forsuch properties Obstetrician James Y Simpson (1811–1870,UK) introduced chloroform for relief of labor pain in Edin-burgh in 1847 John Snow (1813–1858, UK) is recognized asthe first physician to work full time as an anesthetist Relief oflabor pain remained controversial until Snow administeredchloroform to Queen Victoria (1819–1901) during the birth

of Prince Leopold in 1853, and Princess Beatrice in 1857.Equipment to administer anesthetics developed over the nextseveral decades, and the risk of anesthesia became evident asreports of anesthesia-related deaths appeared in newspapersand medical journals

Karl Koller (1857–1944, Austria) discovered the local thetic properties of cocaine, when applied to the conjunctiva,

anes-in 1884 William S Halsted (1852–1922, USA) used it for anerve block later that year, and August Bier (1861–1949,Germany) performed the first clinical spinal anesthetic in

1898, and introduced intravenous regional anesthesia in

1908 Harvey W Cushing (1869–1939, USA) and Ernest

A Codman (1869–1940, USA), while medical students, duced anesthetic records in 1894 Caudal epidural anesthesiawas introduced independently by Jean A Sicard (1872–1929,France) and Fernand Cathelin (1873–1945, France) in 1901.Henry Edmund Gaskin Boyle (1875–1941, UK) introduced a

intro-Essential Clinical Anesthesia Review: Keywords, Questions and Answers for the Boards, ed Linda S Aglio, Robert W Lekowski, and Richard

D Urman Published by Cambridge University Press © Cambridge University Press 2015

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portable apparatus to administer nitrous oxide and oxygen

in 1917 Lumbar epidural anesthesia was introduced by Fidel

Pagés (1886–1923, Spain) in 1921 Torsten Gordh (1907–2010,

Sweden) introduced lidocaine into clinical use in 1944 The

routine use of intravenous barbiturate anesthesia (with agent

pernoston) was introduced by Rudolph Bumm (1899–1942,

Germany) in 1927 Harold R Griffith (1894–1985, Canada)

and Enid Johnson (1909–2001, Canada) introduced curare in

1942 The use of neuromuscular blockers greatly facilitated

surgery in major body cavities, and mechanical ventilation

Laryngoscopy and tracheal intubation became routine

proced-ures, and new drugs (local anesthetics, intravenous agents, and

inhalation anesthetics) were introduced in subsequent decades

Comprehensive anesthesia machines and routine monitoring

equipment were introduced in the 1960s and 1970s Automatic

blood pressure measuring devices, capnography, and pulse

oximetry were introduced in the 1980s Standards for

intra-operative monitoring were developed at Harvard Medical

School, and adopted by the American Society of

Anesthesiol-ogists in 1986 Technological changes have introduced

ultra-sound and echocardiography to our specialty, and

anesthesiologists have expanded their scope of practice to

include perioperative care, critical care, and the treatment of

chronic pain Ambulatory surgery and delivery of anesthesia

care outside the operating rooms are recent developments

Credit for the discovery of general anesthesia ought to be

divided as follows– Clarke for the first use of ether for dental

extraction, Long for introducing ether for general surgery,

Wells for the introduction of nitrous oxide, Morton for

the first successful public demonstration of ether, and

Jackson for the instruction he provided to Morton Anesthesia

is truly one of the most important discoveries in medicine, and

it is unique in that the discovery occurred over a very briefperiod in the 1840s and events related to its discovery tookplace in America

of nitrous oxide anesthesia during dental surgery was onlypartially successful since the patient cried out during theprocedure Charles T Jackson advised Morton about the use ofether, and did not play a role in the discovery of the anestheticproperties of nitrous oxide Morton was the first to publiclydemonstrate the efficacy of ether as an anesthetic, four yearsafter Long

History of anesthesia

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ACC/AHA Guidelines on Perioperative

Cardiovascular Evaluation and Care for Noncardiac

Surgery

Active cardiac conditions

Clinical risk factors

Classification of cardiac risk for noncardiac surgery

Perioperativeβ-blockade

Percutaneous coronary intervention

Hypertension: perioperative management

Pulmonary system evaluation

Airway and anesthetic history

Preoperative laboratory testing

ASA Physical Status Classification System

ASA NPO Guidelines for Fasting

Preoperative assessment: provides an evaluation of the patient’s

anesthetic risk for the proposed procedure, and allows

recom-mendations to be made that help maximize patient safety The

anesthetic risk evaluation is based on the knowledge of the

patient and the surgery The goals of a preoperative assessment

include a history and physical examination (including airway

evaluation, medication usage, and past anesthetic and surgical

experiences), control of comorbidities and perioperative

diseases, laboratory and cardiac testing as indicated, anestheticrisk assessment, anesthetic plan formulation, and patienteducation and informed consent Significant abnormalitiesdetected by the patient’s history, physical exam, and associaterisk factors may necessitate further testing and evaluation if itwill affect the patient’s treatment, management, or outcomes.Cardiovascular system evaluation: cardiovascular status should

be evaluated for all routine preoperative evaluations lar disease has a high prevalence in most patient populations, andcardiovascular complications may result in significant morbidityand mortality It is important to assess functional capacity, symp-toms that may indicate significant cardiac disease, and obtaininformation regarding prior cardiac events and test results

Cardiovascu-Functional capacity: a patient’s functional capacity is based

on history, and is expressed in the form“metabolic equivalent

of task” (MET) MET is defined as the ratio of metabolic rateduring a specific physical activity to a reference metabolic rate

at rest, set by convention to 3.5ml O2/kg/min or equivalently,

1 kcal/kg/h There is an increased perioperative cardiac riskfor patients unable to achieve a 4 MET functional capacity,which is roughly equivalent to climbing two flights of stairs orwalking two city blocks

American College of Cardiology (ACC) and American HeartAssociation (AHA) Guidelines on Perioperative CardiovascularEvaluation and Care for Noncardiac Surgery: offers a step-wiseapproach in the following algorithm:“Cardiac evaluation andcare algorithm for noncardiac surgery based on active clinicalconditions, known cardiovascular disease, or cardiac riskfactors for patients 50 years of age or greater.”

“Active cardiac conditions” definition:

1 Unstable coronary syndromes: unstable or severe angina,may include stable angina in unusually sedentary patients,recent MI (within 30 days)

2 Decompensated heart failure, or worsening or new-onsetheart failure

3 Significant arrhythmias: Mobitz II or third-degree AVblock, symptomatic ventricular arrhythmias,

supraventricular arrhythmias with uncontrolled ventricularrate, symptomatic bradycardia

Essential Clinical Anesthesia Review: Keywords, Questions and Answers for the Boards, ed Linda S Aglio, Robert W Lekowski, and Richard

3

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4 Severe valvular disease: severe aortic stenosis (valve area

<1cm2, pressure gradient>40 mm Hg, or symptomatic),

symptomatic mitral stenosis

“Clinical risk factors” definition:

1 diabetes mellitus

2 renal insufficiency

3 history of cerebrovascular disease

4 history of ischemic heart disease

5 history of compensated or prior heart failure

Classification of cardiac risk for noncardiac surgery:

1 High risk (>5%): emergent (especially in the elderly),

aortic and other major vascular, peripheral vascular,

and prolonged procedures with major blood loss or

fluid shifts

2 Intermediate risk (<5%): carotid endarterectomy, head andneck, intraperitoneal and intrathoracic, orthopedic, andprostate procedures

3 Low risk (<1%): endoscopic, superficial, cataract, andbreast procedures

Based on ACC/AHA guidelines, further testing is directed byclinical assessment findings in relation to the complexity andinvasiveness of the proposed procedure However, emergencysurgical procedures preclude preoperative evaluation, and riskfactor management may require intensive care or postopera-tive invasive cardiac interventions

Perioperative β-blockade: two groups mandated forβ-blockade according to AHA/ACC guidelines are patientsalready taking β-blockers, and vascular patients withrecent positive provocative cardiac testing It is also likely

No No

No Low risk surgery

Functional capacity greater than or equal to 4 METs without

symptoms‡

No or unknown

Yes (Class IIa, LOE B)

Proceed with planned surgery§

Yes (Class I, LOE B)

Class I, LOE B

Yes (Class I, LOE B)

Yes (Class I, LOE C)

3 or more clinical risk factors||

Vascular surgery

1 or 2 clinical risk factors||

Intermediate risk surgery

Consider testing if it will

Proceed with planned surgery Proceed with planned surgery with HR control (Class IIa, LOE B)

or consider noninvasive testing (Class IIb, LOE B) if it will change management

Evaluate and treat per ACC/AHA guidelines

Proceed with planned surgery†

Consider operating room

Operating room Perioperative surveillanceand postoperative risk

stratification and risk factor management

Figure 1.1 Cardiac evaluation and care algorithm for noncardiac surgery based on active clinical conditions, known cardiovascular disease, or cardiac risk factors for patients 50 years of age *See Table 23 for active clinical conditions †See class III recommendations in Table 2.6, Noninvasive Stress Testing ‡See Table 2.1 for estimated MET level equivalent §Noninvasive testing may be considered before surgery in specific patients with risk factors if it will change management.

||Clinical risk factors include ischemic heart disease, compensated or prior heart failure, diabetes mellitus, renal insufficiency, and cerebrovascular disease Consider perioperative β-blockade for populations in which this has been shown to reduce cardiac morbidity/mortality HR, heart rate; LOE, level of evidence (Modified from Fleisher, L A., Beckman, J A., Brown, K A et al 2007 ACC/AHA 2007 Guidelines on Perioperative Cardiovascular Evaluation and Care for Noncardiac Surgery: Executive Summary: A Report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines Circulation 116: 1971–1996.)

Section 1: Preoperative care and evaluation

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Physical exam: involves a general assessment of the patient,

and a targeted exam focusing on the airway and

cardiopulmon-ary system Height, weight, blood pressure, heart rate, respiratory

rate, temperature, and oxygen saturation (and if on supplemental

oxygen) should be recorded Auscultation of the heart and lungs

should be noted for presence of murmurs, and abnormalities

in cardiac rhythms or lung sounds It is also recommended to

do a brief baseline neurologic exam, as well as physical exam of

the patient’s anatomy when procedures such as a nerve block,

regional anesthesia, or invasive monitoring are planned The

airway exam should include evaluation of the patient’s mouth

opening, ability to visualize the posterior pharyngeal structures,

degree of neck mobility, thyromental distance, and dentition

Signs that a challenging tracheal intubation may be encountered

include a short neck, limited range of motion of the neck, large

tongue, and small mouth opening

Preoperative laboratory testing: specific preoperative testing

should be decided on an individual basis, and is appropriate

depending on the nature of the procedure and the patient’s

medical comorbidities Routine laboratory testing for healthy,

asymptomatic patients is not recommended when the history

and physical exam do not detect any abnormalities In order

for a preoperative test to be considered valuable, the results

would need to alter perioperative management

A hemoglobin or hematocrit test is indicated if the surgery

is associated with significant blood loss potential, fluid shifts,

or if the patient has a complex systemic disease resulting in

anemia Platelet counts are indicated if the patient has a history

of low platelets, or has a disease associated with diminished

platelets such as preeclampsia Coagulation studies are

indi-cated if the patient has significant liver disease or known

coagulopathic conditions

EKG should be obtained if the patient has cardiac risk

factors and a history of cardiac disease There is no definitive

recommendation for screening EKGs to be done, but most

institutions use 50 or 60 years old as the age requirement In

the absence of ongoing symptoms or changes in cardiac status,

a prior EKG within three to six months is generally acceptable

Patients with chronic renal failure should have electrolytes,

blood urea nitrogen, and creatinine tested prior to any

signifi-cant surgery Renal dialysis patients should have their

potas-sium level drawn immediately prior to the procedure

ASA Physical Status Classification System: this classification

system reflects the patient’s condition and underlying disease

complexity, and a patient’s ASA status generally correlates with

their perioperative morbidity and mortality rate More

signifi-cant comorbidities may increase perioperative morbidity For

example, a relative risk of serious perioperative complications is

2.2 and 4.4 for ASA patient status 3 and 4 respectively

Class 1: A normal, healthy patient; no disease outside

surgical process

Class 2: A patient with mild to moderate systemic disease,

medically well controlled, with no functional limitation

Class 3: A patient with severe systemic disease that results in

functional limitation

Class 4: A patient with severe, incapacitating systemicdisease that is a constant threat to life (functionallyincapacitated)

Class 5: A moribound patient who is not expected to survivewithout the operation

Class 6: A declared brain-dead patient whose organs arebeing removed for donor purposes

An“E” is added to the classification to designate a patient inwhom surgery is emergent

ASA NPO guidelines for fasting: patients are required to

be nil per os (NPO) prior to undergoing anesthesia to ize the risk of aspiration These guidelines are for electiveprocedures requiring general anesthesia, regional anesthesia,

minim-or sedation/analgesia (i.e., monitminim-ored anesthesia care), but arenot for women in labor In considering NPO times, both thetype and amount of food ingested should be taken into account(see Table 1.1) Also, the type of liquid ingested is typicallymore important than the volume of liquid ingested If thefollowing guidelines are not met, the patient is considered to

be at an increased aspiration risk NPO guidelines for fasting

do not apply for emergency surgical procedures

Questions

1 A 55-year-old gentleman is seen in the preoperative clinic

in anticipation of an upcoming hip replacement surgery.His current medical conditions are well controlled, and hisvital signs are stable in the clinic It is appropriate tocontinue his outpatient medications as currently prescribeduntil his day of surgery, except for the following

clear tea, carbonated beverages, blackcoffee – does not include alcohol)

2 hours

Light meal (e.g., toast and a clear liquid) 6 hours

(Adapted from: Vacanti et al., 2011, p 14.)

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a baseline functional capacity assessment

b an EKG for a patient with a history of hypertension

and hypercholesteremia

c coagulation studies for a laparoscopic cholecystectomy

d platelet count for a preeclamptic patient

e potassium level check for a renal dialysis patient

3 A 62-year-old woman with a past medical history of

compensated CHF, atrial fibrillation, and angina with

activity, and peripheral vascular disease has a recent

diagnosis of breast adenocarcinoma She presents for

preoperative evaluation for a modified mastectomy

Her functional capacity at baseline is 2 METs Her vital

signs include a heart rate of 90, blood pressure 135/88,

respiratory rate 16, with oxygen saturation of 98% on room

air Based on the current ACC/AHA guidelines and care

algorithm, which of the following would be the most

appropriate course of action?

a proceed with planned surgery

b obtain noninvasive cardiac testing for further

evaluation

c after improvement in heart rate control, proceed with

the planned surgery

d obtain a chest radiograph

e postpone the surgery until her cardiologist approves

her for the procedure

Answers

1 b Patients who are on insulin therapy will need to have

their doses adjusted because of the fasting period that is

associated with their procedure preparation As they should

be appropriately NPO the day of their surgery, short-actinginsulin is generally held on the morning of the procedure.Long-acting insulin is typically continued at the usual orreduced dose Serum glucose levels can be checked, andregular insulin can be given as needed However, it is notappropriate to continue the currently prescribed regularinsulin dose as currently when the patient will be fasting

2 c The need for preoperative laboratory testing is based

on the patient’s comorbidities and the proposedsurgical procedure It is not recommended to undergoroutine laboratory testing for asymptomatic patients whohave no abnormalities suspected on history or physicalexam Coagulation studies are indicated for patientswho have known hepatic disease or coagulopathies

Furthermore, laparoscopic cholecystectomy proceduresare not typically procedures that are associated withinducing significant coagulation abnormalities

3 a Based on the ACC/AHA Guidelines on PerioperativeCardiovascular Evaluation and Care for Noncardiac Surgery,this patient would proceed with the planned procedure.Applying the step-wise algorithm to the scenario, this is not

an emergency noncardiac surgery Also, it is important tonote that this patient does not have any “active cardiacconditions” as defined by the ACC/AHA guidelines – shedoes not have decompensated heart failure, nor unstable

or severe angina, and her atrial fibrillation is not associatedwith an uncontrolled ventricular rate Moreover, as herbreast procedure is classified as having low cardiac risk,she may proceed with the planned elective surgery

Further reading

American Society of Anesthesiologists Task

Force on Preanesthesia Evaluation

(2002) Practice advisory for

preanesthesia evaluation: a report by the

American Society of Anesthesiologists

Task Force on Preanesthesia Evaluation

Anesthesiology 96, 485

Eagle, K A et al (2002) ACC/AHA

Guideline Update for Perioperative

Cardiovascular Evaluation for

Non-cardiac Surgery– ExecutiveSummary A report of the AmericanCollege of Cardiology/American HeartAssociation Task Force on PracticeGuidelines (Committee to Update the

1996 Guidelines on PerioperativeCardiovascular Evaluation forNoncardiac Surgery) Anesthesia andAnalgesia 94, 1052–1064

Faust, R J (2002) AnesthesiologyReview, 3rd edn Philadelphia: W.B

Saunders Company, pp 337–339and 517–518

Morgan, G E., Mikhail, M S., and Murray,

M J (2007) Clinical Anesthesiology, 4thedn McGraw-Hill Medical, pp 1–16 and441–463

Vacanti, C A., Sikka, P K., Urman, R U.,Dershwitz, M., and Segal, B S (2011).Essential Clinical Anesthesia New York:Cambridge University Press, pp 7–15

7

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Obstructive lung disease

Chronic obstructive pulmonary disease (COPD)

Definition and classification of COPD

Emphysema

Chronic bronchitis

Pathophysiology of COPD

Treatment of COPD

Perioperative risk assessment of COPD

Preoperative optimization of COPD

Smoking cessation and COPD

Intraoperative management of COPD

Preoperative optimization of asthma

Intraoperative management of asthma

Diagnosis of intraoperative bronchospasm

Restrictive lung disease

Causes of restrictive lung disease

Pathophysiology of restrictive lung disease

Treatment of restrictive lung diseases

Perioperative care of restrictive lung disease

Obstructive lung disease: the two primary obstructive lung

diseases often encountered perioperatively are chronic

obstructive pulmonary disease (COPD) and asthma

COPD: the most common pulmonary disease in the

peri-operative setting It is the fourth leading cause of death in the

United States Tobacco exposure causes 85% of cases

Definition and classification of COPD: COPD is a chronic

lung disease characterized by expiratory airflow limitation,

which is progressive over time The airflow limitation is not

fully reversible (in contrast to asthma), and it is associated with

abnormal inflammatory response in the lungs

Symptoms of COPD include chronic cough, sputumproduction, dyspnea, and progressive exercise intolerancewith dyspnea on exertion

Physical examination findings may include decreasedbreath sounds, wheezes, rhonchi, rales, and prolongedexpiratory phase Oxygen saturation is also useful to helpstratify the patient’s surgical risk

Spirometry is used to confirm the diagnosis and classify theseverity Accepted criterion for COPD is the ratio of forcedexpiratory volume in the first second of expiration toforced vital capacity (FEV1/ FVC)<70% of predicted,and postbronchodilator FEV1<80% of predicted Thestaging system used to classify disease severity is based onthe percent of FEV1

Historically, COPD is subdivided into emphysema andchronic bronchitis, although many patients exhibit features

of both processes

Emphysema: characterized by the destruction of lungparenchyma with normal airways It includes destruction ofcollagen and elastin in the alveolar walls (so the elastic recoil

Table 2.1 Global Initiative for Chronic Obstructive Lung Disease staging criteria

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of the lungs is decreased), which leads to airspace enlargement

distal to the terminal bronchioles This results in increased

lung compliance, and hyperinflation and distortion of the

chest wall

Chronic bronchitis: characterized by inflammation of the

airways, which is associated with increased mucus secretions

and airway mucosa thickening Chronic bronchitis produces

airway obstruction, which can cause V/Q mismatch, hypoxia,

and CO2retention

Pathophysiology of COPD: the pathogenesis of COPDderives from the combined effects of inflammation, increasedoxidative stress, and imbalance in the activity of proteinasesand antiproteinases The pathologic changes are presentthroughout the lung, and progress over time In the largecentral airways, there is enlargement of mucous glands, hyper-plasia of goblet cells, loss of cilia, and decreased ciliary func-tion, which results in such symptoms of increased mucusproduction and abnormal mucus clearance In the airwaywalls, there is infiltration of inflammatory cells, increasedsmooth muscle, and deposition of connective tissue In thesmall airways, there is also chronic inflammation, which causescollagen deposition and airway remodeling The pulmonaryvasculature can also be affected by vessel wall inflammation,smooth muscle deposition, and fibrosis

Expiratory airflow limitation occurs as a result of airwayinflammation, edema, mucus accumulation, airway hyperplasiaand fibrosis, bronchospasm, and loss of radial traction as con-nective tissue is destroyed Expiratory flow is significantlyreduced throughout expiration, and expiratory time is increased.Changes in lung volumes and capacities of COPD patientsinclude increased total lung capacity (TLC), functional residualcapacity (FRC), and residual volume (RV)

Hyperinflation occurs with COPD, which can be fested by diaphragm flattening, rib elevation, and increase inthe cross-sectional thoracic area Ventilation–perfusion (V/Q)mismatching also occurs, and gas exchange is impaired There

mani-is an increase in both physiologic dead space and shunt.Varying degrees of hypercarbia and hypoxemia occur in dif-ferent patients

Exhaled vital capacity (%)

Figure 2.1 Flow–volume curve in normal and COPD patients (From Vacanti

et al 2011 Essential Clinical Anesthesia, Cambridge University Press, p 17.)

Residual volume (RV)

RV

Expiratory reserve volume (ERV)

Inspiratory reserve volume (IRV)

Tidal volume (TV)

ERV TV IRV

Vital capacity (VC)

9

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Pulmonary hypertension may result from the combined

effects of chronic hypoxia and the direct pathologic changes

of the pulmonary vasculature Progressive pulmonary

hyper-tension can cause right ventricular dysfunction and cor

pulmonale

Treatment of COPD:

Treatment of stable COPD: smoking cessation is the only

intervention that slows the progression of COPD Yearly

influenza vaccinations significantly decrease morbidity and

mortality Pharmacologic management is aimed at

providing symptom relief, but does not change the disease

progression It is approached in a step-wise fashion For

early-stage COPD, short-acting inhaled bronchodilators

are used for symptomatic relief For more severe COPD,

long-acting inhaled bronchodilators are used to help relieve

dyspnea, and improve lung function and exercise tolerance

In severe COPD, inhaled corticosteroids help reduce the

frequency of acute exacerbations In patients with

moderate to severe disease, combination therapy with

long-actingβ2-agonists and inhaled corticosteroids may have

additive benefits Comprehensive, multidisciplinary

pulmonary rehabilitation programs may provide

improvement in exercise capacity and quality of life during

all stages of COPD

Treatment of acute exacerbations of COPD: symptoms of

acute exacerbations include worsened dyspnea, wheezing,

cough, increased sputum, a change in the sputum

characteristics, chest tightness, fever, and malaise Acute

exacerbations are often triggered by respiratory tract

infections Initial treatment includes escalation of

bronchodilator therapy, oxygen therapy for hypoxia,

antibiotics if there is evidence of bacterial infection, and

possible systemic corticosteroids The patient should be

admitted to the hospital if they have progressive

hypoxemia, hypercarbia, respiratory distress, or evidence

of new heart failure The highest risk of mortality is with

progressive hypercarbia and respiratory acidosis

Noninvasive mechanical ventilation may be effective to

decrease the need for intubation as well as the mortality

However, patients with refractory hypoxemia, severe

acidosis, or respiratory arrest require intubation and

mechanical ventilation

Treatment of end-stage COPD disease: limited treatment

options for advanced COPD include domiciliary oxygen

therapy, lung volume reduction surgery (LVRS), and lung

transplantation Oxygen therapy increases exercise capacity

and improves survival, and is recommended for patients

with PaO2<55 mm Hg or an arterial oxygen saturation

(SaO2)<89%; or a PaO2<60 mm Hg if the patient has

pulmonary hypertension Contrary to common belief,

oxygen will not increase PaCO2; any increases are most

likely caused by changes in ventilation–perfusion

distribution rather than decreased hypoxic ventilatory

drive LVRS is thought to improve chest wall mechanics in

patients with severe hyperinflation It is a high-riskpalliative treatment, and few patients qualify

Perioperative risk assessment of COPD: patients with COPDhave a 2.7 to 4.7-fold increased risk of perioperative pulmon-ary complications The degree of risk correlates with the sever-ity of COPD Common pulmonary complications areatelectasis, pneumonia, respiratory failure, and acute exacerba-tion of underlying chronic pulmonary disease

Other risk factors for perioperative pulmonary tions include patient’s age >60 years, ASA status II or higher,history of congestive heart failure, current smoking, and type

complica-of surgery Highest risk surgeries are associated with aortic,thoracic, and upper abdominal procedures Other increasedrisk surgeries include neurosurgery, head and neck surgery,emergency surgery, and prolonged surgery (>3 hours).Current recommendations include pulmonary functiontests (PFTs) for all lung resection candidates, and obtaining achest radiograph for patients with known cardiopulmonarydisease or those older than 50 years who are undergoinghigh-risk operations Spirometry may be used to predictlong-term functional status after a major lung resection How-ever, preoperative spirometry does not predict the risk of

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Further reading

Sundar, S., Erlich, J M., and Sundar, E

(2011) Anesthetic goals in patients with

valvular heart disease In Vacanti, C A.,

Sikka, P K., Urman, R U., Dershwitz, M.,

and Segal, B S (eds) Essential Clinical

Anesthesia New York, NY: Cambridge

University Press, pp 28–36

Townsley, M and Martin, D E (2013)

Anesthetic management for the surgical

treatment of valvular heart disease

In Hensley, F A., Martin, D E., and

Gravlee, G.P (eds) A Practical Approach

to Cardiac Anesthesia, 5th edn

Philadelphia, PA: Lippincott Williams &

Wilkins, pp 319–358

Wilson, W., Taubert, K A., Gewitz, M et al

(2007) Prevention of infectiveendocarditis: a guideline from theAmerican Heart Association RheumaticFever, Endocarditis, and KawasakiDisease Committee, Council onCardiovascular Disease in the Young,and the Council on Clinical Cardiology,Council on Cardiovascular Surgeryand Anesthesia, and the Quality of

Care and Outcomes ResearchInterdisciplinary Working Group

Circulation, 116: 1736–1754,e376–e377

Vacanti, C A., Sikka, P K., Urman, R U.,Dershwitz, R., and Segal, B.S (eds)(2011) Essential Clinical Anesthesia,1st edn New York, NY: CambridgeUniversity Press, p 32

Morgan, G E., Mikhail, M S., andMurray, M J (eds) (2006) ClinicalAnesthesiology, 4th edn McGraw-Hill,

p 467

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Causes of rapid desaturation: obesity

Hypoxemia in morbid obesity: cause

Morbid obesity: airway evaluation

Morbid obesity: pulmonary function

Morbid obesity: hypoxemia physiology

Morbid obesity: PFTs

Morbid obesity: pharmacokinetic considerations

Morbid obesity: rapid desaturation

Obesity: risk of aspiration

Current obesity classifications are as follows: overweight (BMI

25.00–29.99 kg/m2); class I obesity (BMI 30.00–34.99 kg/m2

);

class II obesity (BMI 35.00–39.99 kg/m2

); class III obesity(BMI 40.00 kg/m2) Perioperative risk, as well as mortality,

increases with increasing BMI The obese patient presents

unique challenges throughout the perioperative period due to

changes in several organ systems

Obesity and the cardiovascular system

Obesity results from an imbalance between energy supply and

demand Energy needs and oxygen consumption are increased

by as much as 25% This demand is met by an increase in

minute ventilation and cardiac output

The obese patient is more likely to have altered

cardiopul-monary mechanics, which can lead to V/Q mismatch, and

hypoxemia Obese patients are more likely to have underlying

heart disease, which may be undiagnosed as usual signs and

symptoms (edema, increased jugular venous distention,

dys-pnea on exertion, orthodys-pnea, etc.) may be difficult to identify

secondary to body habitus or physical inactivity For this

reason, these patients frequently require preoperative

cardiovas-cular evaluation, including EKG, CXR, and echocardiography

Obesity and the pulmonary system

The obese patient may present with an increased neck

circumfer-ence or excess pharyngeal tissue, which may indicate a

predis-position to upper airway obstruction and difficult mask ventilation

Obese patients also have decreased functional residualcapacity (FRC), decreased total lung capacity (TLC), and PFTsconsistent with restrictive pathology as a result of decreaseddiaphragmatic mobility due to adipose tissue in the thoraxand abdomen Induction of anesthesia and the supine positionfurther decrease FRC This combination of decreased FRC andincreased oxygen requirements causes obese patients to desatu-rate quickly when apneic The decreased FRC also predisposesthese patients to atelectasis, as closing capacity (CC) mayexceed FRC

The incidence of obstructive sleep apnea (OSA) is nearly90% in the morbidly obese Frequently, it may be undiagnosed.OSA occurs as a result of excess pharyngeal tissue, whichcollapses and obstructs the upper airway when the patient isasleep, sedated, or anesthetized The presence of OSA shouldalert the anesthesiologist to the possibility of a difficult airway,specifically difficult mask ventilation

Patients with OSA benefit from perioperative CPAP use.Long-term OSA, particularly if not treated with continuouspositive airway pressure (CPAP), may lead to “obesity-hypoventilation,” or “Pickwickian” syndrome, which is a condi-tion of obesity, hypoxemia, hypercarbia, daytime somnolence,polycythemia, pulmonary hypertension, and ultimately rightheart failure

Obesity and the renal system

Obese patients have increased renal blood flow (RBF),glomerular filtration rate (GFR), and tubular reabsorption.This increase may be related to the overall increased bloodvolume and cardiac output seen in the obese state Increases

in RBF and GFR lead to increased excretion of renally cleareddrugs This baseline increase in GFR also makes these patientsmore susceptible to hypovolemia and prerenal azotemia,particularly as a result of diuretic, angiotensin-convertingenzyme inhibitor (ACEI), or nonsteroidal anti-inflammatorydrug (NSAID) use Volume loading and maintenance of euvo-lemia is very important in these patients Intraoperative fluidrequirement may be higher than calculated for normal-weightpatients

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Obesity and the gastrointestinal system

Obesity alone does not increase aspiration risk Obesity does

present challenges in airway management, however, which may

significantly contribute to the risk of aspiration in these patients

Obese patients frequently have hepatobiliary disease, such

as fatty liver infiltration and cholelithiasis Abnormalities in

cholesterol metabolism predisposes these patients to hepatic

dysfunction and postoperative gallstones

Induction of anesthesia in the obese patient

Obese patients have many characteristics that predispose them

to difficult airway management and rapid oxygen desaturation.Adequate time and preparation is crucial for safety duringanesthetic induction and airway management A ramp should

be placed under the patient to optimize intubating conditions,and preoxygenation should be accomplished in a 30° reverseTrendelenburg or sitting position

Increase in adipose tissue

Cardiomegaly

Hypertension–

systemic, pulmonary

Ischemic heart disease

Increased stroke volume

Normal heart rate

Congestive heart failure

Increased cardiac output

Increased blood volume

Figure 5.1 Cardiovascular changes in obesity (From Vacanti et al 2011 Essential Clinical Anesthesia, Cambridge University Press, p 38.)

Increase in adipose tissue

Decreased expiratory reserve volume

Normal residual volume

Decreased functional residual capacity

Decreased vital capacity, total lung capacity

Normal closing capacity

Restrictive

ventilatory

defect

Decreased lung volumes and capacities

Figure 5.2 Pulmonary changes in obesity.

(From Vacanti et al 2011 Essential Clinical Anesthesia, Cambridge University Press, p 39.)

23

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Airway equipment, including intubating laryngeal mask

airway (LMA), bougie, video laryngoscope, or fiberoptic

bron-choscope should be readily available An LMA can be an

effective alternative to ventilation should mask ventilation

prove difficult BMI >26 has been shown to be a risk factor

for difficult mask ventilation Similarly, neck circumference>40

cm and Mallampati score of 3 or greater has been linked to

difficult intubation in the obese population

Preinduction administration of metoclopramide or H2

blockers to minimize the effects of aspiration may be

con-sidered, but has not been shown to reduce the risk of

aspir-ation If aspiration is of concern, rapid sequence induction

with cricoid pressure should be pursued

Obesity and pharmacokinetics

The increased cardiac output and overall hypervolemic state

of obese patients may increase drug requirements Lipophilic

drugs, such as propofol, benzodiazepines, and opioids,

often have a larger volume of distribution in these patients

Therefore induction or loading doses of lipophilic

medica-tions should be calculated based on total body weight (TBW),

not ideal body weight (IBW) Hydrophilic drugs, such as

nondepolarizing neuromuscular blockers, do not have alarger volume of distribution and should be dosed byIBW Succinylcholine, however, should be dosed by TBWdue to increased plasma cholinesterase activity in obesepatients Repeat dosing, of both lipophilic and hydrophilicdrugs, and calculation of infusion rates, particularly foropioids, should be based on IBW The increased RBF andGFR, and the resultant increased renal clearance found inobese patients, should be kept in mind when dosingmedications

Sevoflurane and desflurane have been identified as optimalinhalational agents for obese patients, due to their rapid andconsistent recovery profiles, hemodynamic control, decreasedincidence of postoperative nausea/vomiting, and overall cost-effectiveness More lipophylic agents such as isoflorane mayhave prolonged duration of action

Obesity and regional anesthesia

Regional anesthesia, including epidural and spinal anesthesia,although more technically challenging, may safely be per-formed in the obese patient Importantly, in-dwelling cathetersmay be more likely to migrate, sympathetic blockade may spread

Table 5.1 Organ system, comorbidity, and anesthetic implications

Cardiovascular Hypervolemic state Increased volume of distribution, hypertension

CHF (systolic and diastolic

Ischemic heart disease Myocardial infarction, heart failure

Peripheral vascular disease Reduced blood flow, limb ischemia, poor wound healing

Restrictive lung volumes Shorter time to hypoxia, difficult oxygenationDifficult airway management Difficult ventilation and intubation, pulmonary aspirationEndocrine Diabetes and insulin resistance Cardiovascular disease, central obesity, perioperative glucose control

Gastrointestinal Gastroparesis Pulmonary aspiration, delayed gastric emptying PONV?

Hepatobiliary disease Cholelithiasis, biliary obstruction, hepatic insufficiencyRenal Increased GFR, RBF Predisposition to renal insufficiency, greater fluid requirements, altered clearance

of drugs; consider discontinuation of ACE inhibitors and/or diureticsCNS Hypersensitivity to CNS depressants Hypersomnolence, central apnea, reduced drug requirement

Cerebrovascular disease Decreased cerebral blood flow

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more cephalad, and neuraxial opioids may have an increased

respiratory depressant effect in these patients

Intraoperative considerations

Maintaining oxygenation may be an intraoperative challenge

in obese patients, due to decreased FRC and respiratory

compliance Recruitment maneuvers and use of positive

end-expiratory pressure (PEEP), up to 15 cm H2O, have been

shown to improve oxygenation

Avoidance of nitrous oxide, or limiting it to <50%, may

also be beneficial in these patients

Obese patients undergoing laparoscopy may have further

reduced FRC and pulmonary mechanics due to Trendelenburg

positioning and pneumoperitoneum V/Q mismatching may

worsen, leading to hypoxemia and hypercarbia, which may

lead to acidosis, increased pulmonary vascular resistance, and

right heart strain Absorption of CO2from laparoscopic

insuf-flation further worsens these effects

Positioning may be another important intraoperative

con-sideration for obese patients Standard protective positioning

equipment designed for nonobese patients may not work well

for these patients, and they may suffer untoward consequences

as a result For this reason, increased vigilance and monitoring

of pressure points may be necessary

Postoperative considerations

Obese patients have increased morbidity and mortality in the

postoperative period due to OSA, increased sensitivity to

respiratory depressants, reduced cardiopulmonary reserve,

and increased risk for thromboembolic events Early use of

BiPAP or CPAP has been shown to decrease incidence of

postoperative hypoxia in these patients

Perioperative DVT prophylaxis with either subcutaneous

heparin or LMWH has been shown to decrease DVT risk

Non-opioid-based pain management strategies, including

the use of regional anesthesia, NSAIDs, and ketamine, are

recommended to avoid respiratory depression and subsequent

cardiopulmonary morbidity and mortality

a All medications should be dosed according to TBW

b Lipophilic medications should be dosed according

2 b Pulmonary hypertension occurs as a result ofhypoxia and hypercarbia, which occurs in obstructivesleep apnea

3 d Induction or loading doses should be dosed by TBW.Repeat doses should be based on IBW

Further reading

Nguyen, L C and Jones, S B (2011) Obesity

In Vacanti, C A., Sikka, P J., Urman, R

D., Dershwitz, M., and Segal, B S (eds)

Essential Clinical Anesthesia Cambridge:

Cambridge University Press, p 38

Casati, A and Putzu, M (2005) Anesthesia

in the obese patient: pharmacokinetic

considerations Journal of ClinicalAnesthesia 17(2), 134–145

Passannante, A N and Rock, P (2005)

Anesthetic management of patients withobesity and sleep apnea AnesthesiologyClinics of North America 23(3), 479–491

Ebert, T., Shankar, H., and Haake, R (2006)

Perioperative considerations for patients

with morbid obesity AnesthesiologyClinics 24, 621–636

Passannante, A and Tielborg, M (2009).Anesthetic management of patientswith obesity with and without sleepapnea Clinics in Chest Medicine 30,569–579

25

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Chronic renal failure

Lab assessment of renal function

Azotemia

Uremia

Dialysis effects

Renal failure: electrolyte effects

Contrast-induced nephropathy prevention

Hyperkalemia treatment

Hypermagnesemia treatment

Renal failure: comorbidities

Renal failure: platelet function

Renal failure: pharmacokinetics

Chronic renal failure (CRF) is defined by an estimated

glomerular filtration rate (GFR) <60 ml/min/1.73m2 for at

least three months It results in impaired handling of fluids

and acid loads, regulation of electrolytes, and excretion of

medications

Lab assessment of renal function: the most accurate study is

the creatinine clearance rate (CCR)¼ (urine creatinine × urine

flow rate)/(serum creatinine) based on 24-hour urine

collec-tion However, two-hour tests are relatively accurate as well

BUN and Cr are good screening tools but not as accurate

CRF severity is classified based on estimated GFR

Azotemia refers to retention of nitrogenous waste products

due to renal insufficiency

Uremia is the clinical manifestation of multiorgan system

derangement due to advanced renal insufficiency Blood urea

nitrogen (BUN) serves as a marker, although this can be

elevated due to non-renal causes

Renal failure comorbidities

Cardiovascular:

congestive heart failure (CHF) from chronic fluid overload,

anemia, accelerated atherosclerosis, uremia-induced

CNS dysfunction secondary to uremic encephalitis

peripheral and autonomic neuropathy leading toorthostatic hypotension, impaired circulatory response toanesthesia, silent ischemia, and impaired gastric emptyingHematology/immunology:

anemia requiring EPO and/or transfusions

uremic coagulopathy caused by altered platelet functionand worsened by anemia (RBCs release ADP, inactivating

Time

2 )

0 30 60

90 Normal

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prostacyclin and enhancing platelet–vessel wall

interactions); PT, PTT, and platelet count may be normal

despite uremic coagulopathy

leukocyte and immune dysfunction due to uremia,

malnutrition and dialysis-induced inflammatory response;

increased exposure to infections from dialysis grafts,

catheters and blood products

GI/nutrition:

malnutrition leading to greater risk of poor wound healing,

infection, prolonged recovery from illness

uremia-induced enteropathy, peptic ulcer disease, and

nausea/vomiting

Renal failure: electrolyte effects

Hyperkalemia treatment: administer calcium chloride,

beta-agonists, intravenous insulin and dextrose, diuretics (e.g.,

furosamide), kayexalate or dialysis

Hypermagnesemia treatment: administer intravenous

calcium, loop diuretic along with 5% dextrose and ½ normal

saline infusion

Dialysis effects

Dialysis can cause a coagulopathy from anticoagulation agents

required for hemodialysis Also, blood samples taken

immedi-ately after hemodialysis can produce inaccurate results as

redistribution of fluid and electrolytes takes about six hours

Lastly, dialysis“disequilibrium syndrome” (less common with

peritoneal dialysis) may occur if fluid and electrolyte shifts are

too rapid, leading to weakness, nausea, vomiting, convulsions,

and coma

Complications associated with chronic renal failure

Patients with CRF are at high risk of perioperative renal

disease progression due to increased sensitivity to

hypovole-mia, nephrotoxins, and hemodynamic perturbations They are

also at risk of developing profound acidemia, particularly in

the postoperative period when residual anesthetics and opioids

lead to CO2 retention, given baseline diminished buffer base

reserve secondary to impaired acid excretion Uremia-induced

nausea and vomiting are also common in CRF patients, which

increases the risk of aspiration during induction and

emer-gence from anesthesia Other risks to consider include surgical

bleeding, GI bleeding, intracerebral hemorrhage, and

hemor-rhagic pericardial effusion

Contrast-induced nephropathy

Prevent contrast-induced nephropathy by pretreating with oralN-acetylcysteine, sodium bicarbonate infusion, periproceduralhemofiltration, and by postponing elective surgery for at leasttwo days after contrast administration

Renal failure: pharmacokinetics

Chronic renal failure leads to altered pharmacokinetics due toaltered volume, electrolytes, pH, decreased serum protein,impaired biotransformation and excretion While lipid-solubledrugs are metabolized by the liver to water-soluble forms beforeelimination by the kidneys, ionized drugs are eliminatedunchanged by the kidneys and so their duration of action may

be prolonged in CRF Opioids and sedatives, for example, morecommonly cause respiratory depression in patients with CRF.Loading doses of most drugs administered by bolus orshort-term infusion do not need to be altered significantly inCRF since their duration of action is determined by redistri-bution not elimination Maintenance doses, however, do needreduction in CRF as they depend on elimination

Preoperative considerations:

Avoid hemodialysis on the day of surgery due to risk ofrebound anticoagulation, fluid shifts, hypokalemia, andhypoxemia

Consider RBC transfusion if Hb ≤8 g/dl, or if Hb <10 g/dlfor major surgery

Minimize risk of coagulopathy by administeringcryoprecipitate, dDAVP or conjugated estrogens,performing heparin-free dialysis, or treating anemia withRBC transfusion or erythropoietin

Intraoperative considerations:

Set up

Minimize premedication given susceptibility to excesssedation and respiratory depression

Utilize strict aseptic technique for all invasive procedures

Avoid urinary catheters if patient is anuric given increasedrisk of infections

Carefully position patients as they are at high risk forfractures from renal osteodystrophy and inability to reportdiscomfort from sensory neuropathy

Induction

Manage increased risk of aspiration by reducing gastricacidity and promoting gastric emptying with H2blockers,metoclopramide, and citric acid/sodium citrate

Table 6.1 Electrolyte derangements in renal failure patients

Causes skeletal weakness andpotentiates nondepolarizingmuscle relaxants

Associated with renal osteodystrophyand calciphylaxis especially in bloodvessels and skin

27

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Reduce dose of induction drugs and slow rate of infusion

given increased risk of hypotension

Anticipate hypotension and manage with fluids and

vasopressors

Check serum K+concentration prior to succinylcholine

administration

Maintenance

Reduce sedative and anesthetic doses

Avoid renally excreted neuromuscular blockers (NMBs)

Administer fluids and blood to permit adequate organperfusion even if dialysis is required postoperatively oreven intraoperatively

Table 6.2 Pharmacologic considerations for commonly used perioperative drugs in patients with CRF

Inhalational

anesthetics Eliminated primarily by the lungs Sevoflurane has potentially nephrotoxic metabolite (compound A)Lipid soluble

Benzodiazepines Increased free fraction in CRF Potentiated clinical effect in CRF

Certain metabolites are pharmacologically active and accumulatewith repeated dosing

Barbiturates Free fraction of induction dose is almost

doubled in patients with CRF Exaggerated clinical effect in CRF Need to reduce induction dosePropofol Rapid, extensive hepatic metabolism

Pharmacokinetics unchanged in CRF Effects are not prolonged in CRF

Ketamine Redistribution and hepatic metabolism largely

responsible for termination of anestheticeffects Minimal change in free fraction in CRF

CFR does not alter clinical effects

Active metabolites may prolong action with chronic administration:Morphine-6-glucuronide (morphine) has potent analgesic andsedative effects; Normeperidine (meperidine) has neurotoxic effects;Hydromorphone-3-glucuronide (hydromorphone) can causecognitive dysfunction and myoclonus; Fentanyl has no activemetabolites

Ionized drugs

Muscle relaxants Standard dose of succinylcholine raises

serum K+0.5–0.8 mEq/L, which is unchanged

inhibitors Decreased elimination in CRF and half-life isprolonged Half-life prolongation is similar or greater than the duration ofblockade from long-acting NMBs so recurarization is rarely seen

Vasoactive drugs

and may reduce renal blood flowSodium

nitroprusside Metabolized by the kidney and excreted asthiocyanate Toxicity from thiocyanate accumulation is more likely in CRFAntibiotics Penicillins, cephalosporins, aminoglycosides,

and vancomycin are predominantlydependent on renal elimination

Loading dose is unchanged but maintenance doses aresubstantially reduced

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Controlled ventilation is often preferable since

spontaneous ventilation may result in hypercarbia,

exacerbated acidemia, and hyperkalemia

Emergence

Anticipate potential delayed emergence, aspiration,

hypertension, respiratory depression, and pulmonary edema

Ensure adequate reversal of neuromuscular blockade

Postoperative considerations:

It is important to monitor for CV complications (EKG,

Troponin I), pulmonary edema (CXR), and hyperkalemia in

patients with chronic renal failure In considering these results,

one should also evaluate the need for postoperative dialysis

Questions

1 Renal function is best assessed by:

a BUN:Cr ratio

b creatinine clearance rate

c creatinine plasma concentration

d urine flow rate and specific gravity

2 The following are treatments for hyperkalemia EXCEPT:

a dialysis

b beta-blocker

c dextrose and insulin infusion

d intravenous calcium chloride

3 Renal failure associated coagulopathy in a patient withanemia can be treated with:

a vitamin K administration

b fresh frozen plasma

c red blood cell transfusion

d platelet transfusion

Answers

1 b The most accurate assessment of renal function is thecreatinine clearance rate (CCR) ¼ (urine creatinine × urineflow rate)/(serum creatinine) based on 24-hour urinecollection

2 b Beta-agonists, not beta-blockers, are used to treathyperkalemia by shifting potassium intracellularly

3 c Uremic coagulopathy is worsened by anemia, as RBCsrelease ADP, which normally inactivates prostacyclinand enhances platelet–vessel wall interaction For thisreason, PT, PTT, and platelet count may be normal despiteuremic coagulopathy

Further reading

Bittner, E A (2011) Chronic renal failure

In Vacanti, C A., Sikka, P J., Urman, R

D., Dershwitz, M., and Segal, B S (eds)

Essential Clinical Anesthesia

Cambridge: Cambridge University Press,

pp 43–48

ABA Key Words (2013) Open Anesthesia

Media Wiki.www.openanesthesia.org/

McCarthy, D and Shorten, G (2011)

Chronic kidney disease In B.J PollardHandbook of Clinical Anesthesia, 3rd edn.CRC Press, pp 203–206

29

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Child–Turcotte–Pugh (CTP) classification

Model for end-stage liver disease (MELD)

Fulminant hepatic failure

Anatomy and physiology

The liver is the largest of the solid organs in the body

and weighs approximately 1,500 g The anatomy of the liver

can be described by using the morphology or functional aspects

The liver is made up of two lobes– right and left – which are

separated by the falciform ligament The right lobe is larger and

has two additional lobes, the caudate and the quadrate lobes

The liver anatomy can also be described by functional anatomy

Claude Couinaud divided the liver into eight functionally

independent segments, which each have their own vascular

inflow and outflow as well as biliary drainage

The blood supply to the liver is from the portal vein (about

75%) and the hepatic artery Normal portal vein pressure is

approxi-mately 10 mm Hg, and normal hepatic artery pressure is arterial

Normal hepatic blood flow is about 1,500 ml/min, which correlates

to 25% of cardiac output The liver is supplied by sympathetic nerve

fibers (T6–11) Many important functions are performed by the

liver, including metabolic functions (carbohydrate, fat, protein, and

drug metabolism), bile secretion, bilirubin excretion, albumin

production, ammonia excretion, and synthesis of all the coagulation

factors except for factor VIII and von Willebrand factor

Hepatic blood flow is decreased by any cause that results in

a lower systemic blood pressure and cardiac output Causesinclude general and regional anesthesia (spinal/epidural), posi-tive pressure ventilation, hypoxemia, and beta-blockers

Liver cirrhosis

When providing anesthesia for a patient with liver disease, it isimportant to know that liver disease is a multiorgan disorderthat leads to a variety of pathophysiologic derangements.Liver disease often may progress to cirrhosis Cirrhosis ischaracterized by hepatic cell death, fibrosis, as well as regen-erative nodules

Portal hypertension is a common sequela seen in patientswith chronic liver disease Associated findings includeascites, portosystemic shunts, hepatic encephalopathy, andsplenomegaly

Risk stratification of the cirrhotic patient

The Child–Turcotte–Pugh (CTP) classification, the model forend-stage liver disease (MELD), and the pediatric version(PELD) are liver failure classification systems that are utilized

to assess prognosis The CTP classification is based on fivevariables (bilirubin, albumin, INR or PT, ascites, and enceph-alopathy) and groups patients by score to determine theirprognosis The MELD is a statistical model based on serumbilirubin, serum creatinine, and INR to determine the severity

of the liver disease as well as the need for a liver transplant

Effects of liver disease Gastrointestinal

Portal hypertension is defined as pressure in the portalvein >10 mm Hg High portal pressure causes portovenouscollaterals to develop These collaterals are commonly found

at four sites – esophageal, periumbilical, retroperitoneal, andhemorrhoidal

The finding of ascites is one of the hallmarks of pensated liver cirrhosis Ascites is caused by changes in

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