Obstetric Anesthesia This page intentionally left blank Obstetric Anesthesia Craig M. Palmer, MD Professor of Anesthesiology University of Arizona Tucson, Arizona Robert D’Angelo, MD Professor, Obstetric and Gynecologic Anesthesia Wake Forest University School of Medicine Winston-Salem, North Carolina Michael J. Paech, FANZCA Winthrop Professor and Chair of Obstetric Anaesthesia School of Medicine and Pharmacology The University of Western Australia Perth, Australia 1 1 Oxford University Press, Inc., publishes works that further Oxford University's objective of excellence in research, scholarship, and education. Oxford New York Auckland Cape Town Dar es Salaam Hong Kong Karachi Kuala Lumpur Madrid Melbourne Mexico City Nairobi New Delhi Shanghai Taipei Toronto With offi ces in Argentina Austria Brazil Chile Czech Republic France Greece Guatemala Hungary Italy Japan Poland Portugal Singapore South Korea Switzerland Thailand Turkey Ukraine Vietnam Copyright © 2011 by Oxford University Press, Inc. Published by Oxford University Press, Inc. 198 Madison Avenue, New York, New York 10016 www.oup.com Oxford is a registered trademark of Oxford University Press All rights reserved. No part of this publication may be reproduced, stored in a retrieval system, or transmitted, in any form or by any means, electronic, mechanical, photocopying, recording, or otherwise, without the prior permission of Oxford University Press. Palmer, Craig M., author. Obstetric anesthesia / Craig M. Palmer, Robert D'Angelo, Michael J. Paech p. ; cm. Includes bibliographical references and index. ISBN 978-0-19-973380-4 1. Anesthesia in obstetrics. 2. Analgesia. I. D'Angelo, Robert, author. II. Paech, Michael J., author. III. Title. [DNLM: 1. Anesthesia, Obstetrical. 2. Analgesia, Obstetrical. 3. Gynecologic Surgical Procedures—methods. WO 450] RG732.P36 2011 617.9'682—dc22 2010050965 This material is not intended to be, and should not be considered, a substitute for medical or other professional advice. Treatment for the conditions described in this material is highly dependent on the individual circumstances. And, while this material is designed to offer accurate information with respect to the subject matter covered and to be current as of the time it was written, research and knowledge about medical and health issues is constantly evolving and dose schedules for medications are being revised continually, with new side effects recognized and accounted for regularly. Readers must therefore always check the product information and clinical procedures with the most up-to-date published product information and data sheets provided by the manufacturers and the most recent codes of conduct and safety regulation. The publisher and the authors make no representations or warranties to readers, express or implied, as to the accuracy or completeness of this material. Without limiting the foregoing, the publisher and the authors make no representations or warranties as to the accuracy or effi cacy of the drug dosages mentioned in the material. The authors and the publisher do not accept, and expressly disclaim, any responsibility for any liability, loss or risk that may be claimed or incurred as a consequence of the use and/or application of any of the contents of this material. 9 8 7 6 5 4 3 2 1 Printed in the United States of America on acid-free paper Contents Preface vii Contributors ix Abbreviations xi 1. Neuroanatomy and Neurophysiology 1 2. Anatomic and Physiologic Changes of Pregnancy 19 3. Pain Relief for Labor and Delivery 31 4. Anesthesia for Cesarean Delivery 79 5. Post-Cesarean Analgesia 156 6. Anesthesia for Surgery During and After Pregnancy 182 7. Pregnancy Induced Hypertension and Preeclampsia 199 8. Obstetric Hemorrhage 213 9. Obesity 242 10. Coexisting Disease and Other Issues 265 11. Complications of Labor and Delivery 314 12. Fetal Assessment and Care 342 13. Management of Later Complications of Obstetric Anesthesia and Analgesia 361 14. Critical Care of the Obstetric Patient 392 15. Neonatal Resuscitation 402 Index 415 This page intentionally left blank Preface Obstetric anesthesia is a rapidly expanding, constantly evolving fi eld; some years ago we saw a need for a practical guide to patient care and management—one that could be consulted quickly (and often) to outline a concrete course of clinical management, covering how to manage specifi c patients in specifi c situations. What drug to give, how to give it, how much to give, and when to stop and try something different. Our goal has been to provide anesthesiologists and anes- thetists, both in training and in practice, with that practical reference. Our fi rst attempt to provide such a reference met many of these objectives, but in one area fell far below our vision. In 2002 we pub- lished the Handbook of Obstetric Anesthesia with a different publisher, vii who had their own vision for the text, and while the information and style of the Handbook were what we envisioned, its physical form was not. Rather than being a pocket-sized, inexpensive, “ready reference,” it was a larger, hardcover text. While visually appealing, it was more at home on a bookshelf than in the pocket of a scrub suit or on an anesthesia cart. With our new partnership with Oxford University Press, we have at last achieved what we set out to do 10 years ago. We have worked diligently to make the information easy to use—when possible, we have tried to distill essential information into tables, charts, diagrams, and fl owcharts that can be quickly accessed and applied. We have used bullet points to highlight key points of management, and the essential background, rationale, and science behind clinical decision making. This is not intended to be an exhaustive reference textbook, although the readings and references at the end of each chapter do provide additional background and the basis for further study. Of course, there is usually more than one means to an end, but where our experience has shown one approach works best, we’ve advocated it. Where there are equally viable options, we’ve tried to present each, with the advantages and disadvantages of alternative approaches. All three of us have dedicated our careers to the anesthetic care of obstetric patients, as have our contributors. We care for these PREFACE patients and deal with these problems every day. Obstetric Anesthesia draws on our experience and study to tell you what we do, how we do it, and why. Craig M. Palmer, MD Robert D’Angelo, MD Michael J. Paech, FANZCA viii Contributors Valerie A. Arkoosh, MD, MPH Professor of Clinical Anesthesiology and Critical Care Professor of Clinical Obstetrics and Gynecology University of Pennsylvania School of Medicine Philadelphia, PA Emily Baird, MD, PhD Assistant Professor of Clinical Anesthesiology and Critical Care University of Pennsylvania School of Medicine Philadelphia, PA Laura S. Dean, MD ix Assistant Professor, Obstetric & Gynecologic Anesthesia Wake Forest University School of Medicine Winston-Salem, NC Kenneth E. Nelson, MD Associate Professor, Obstetric & Gynecologic Anesthesia Wake Forest University School of Medicine Winston-Salem, NC Medge D. Owen, MD Professor, Obstetric & Gynecologic Anesthesia Wake Forest University School of Medicine Winston-Salem, NC John A. Thomas, MD Associate Professor, Obstetric & Gynecologic Anesthesia Wake Forest University School of Medicine Winston-Salem, NC This page intentionally left blank Abbreviations Ach acetylcholine ACOG American College of Obstetricians and Gynecologists AMPA α -amino-3-hydroxy-5-4-isoxazolepropionic acid ASA American Society of Anesthesiologists BP blood pressure bpm beats per minute CNS central nervous system CPD cephalopelvic disproportion CS cesarean section xi CSEA combined spinal-epidural anesthesia CSF cerebrospinal fl uid DIC disseminated intravascular coagulation EA epidural anesthesia EBP epidural blood patch ECG electrocardiogram ECV external cephalic version EGA estimated gestational age FHR fetal heart rate FRC functional residual capacity GA general anesthesia HOCM hypertrophic obstructive cardiomyopathy ICP intracranial pressure IM intramuscular IU international units IUGR intrauterine growth retardation IV intravenous IVC inferior vena cava IVH intraventricular hemorrhage LA local anesthetic LBW low birth weight LMA laryngeal mask airway ABBREVIATIONS LMWH low molecular weight heparin LOR loss of resistance MAC minimum alveolar concentration mcg microgram MLK myosin light-chain kinase MMR maternal mortality ratio N NMDA -methyl-D-asparate NSAIDs nonsteroidal anti-infl ammatory drugs NYHA New York Heart Association PCEA patient-controlled epidural anesthesia xii PCIA patient-controlled intravenous analgesia PDPH post-dural puncture headache PE pulmonary embolism PIH pregnancy-induced hypertension ppm parts per million PPV positive-pressure ventilation PTL preterm labor PVR pulmonary vascular resistance RDS respiratory distress syndrome SA spinal anesthesia SVC superior vena cava SVR systemic vascular resistance TPA tissue plasminogen activator UFH unfractionated heparin UPP uterine perfusion pressure WDR wide dynamic range Chapter 1 Neuroanatomy and Neurophysiology Craig M. Palmer , MD Introduction 1 Neuroanatomy 1 Neuropharmacology 8 1 Introduction The practice of obstetric anesthesia, more than any other subspecialty area within current anesthetic practice, is rooted in regional anesthe- sia techniques, primarily neuraxial blockade. In recent decades, our understanding of the structure and function of the nervous system, at every level (particularly