Monitoring in Anesthesia and Perioperative Care 2011 PDF

Monitoring in Anesthesia and Perioperative Care Monitoring in Anesthesia and Perioperative Care is a practical and comprehensive resource documenting the current art and science of perioperative patient monitoring, addressing the systems-based practice issues that drive the highly regulated health...

Monitoring in Anesthesia and Perioperative Care Monitoring in Anesthesia and Perioperative Care is a practical and comprehensive resource documenting the current art and science of perioperative patient monitoring, addressing the systems-based practice issues that drive the highly regulated health care industry of the early 21st century. Initial chapters cover the history, medicolegal implications, validity of measurement, and education issues relating to monitoring. The core of the book addresses the many monitoring modalities, with the majority of the chapters organized in a systematic fashion to describe technical concepts, parameters monitored, evidence of utility, complications, credentialing and monitoring standards, and practice guidelines. Describing each device, technique, and principle of clinical monitoring in an accessible style, Monitoring in Anesthesia and Perioperative Care is full of valuable advice from the leading experts in the field, making it an essential tool for every anesthesiologist. David L. Reich, M.D. was named Professor and Chair of Anesthesiology at the Mount Sinai School of Medicine in New York in 2004, where he had been Co-Director of Cardiothoracic Anesthesia since 1990. Dr. Reich’s research interests include neurocognitive outcome following thoracic aortic surgery, outcome effects of intraoperative hemodynamics, medical informatics, and hemodynamic monitoring. He has published more than 90 peer-reviewed articles and more than 30 book chapters, and he is an associate editor of the text Cardiac Anesthesia and editor-in-chief of Seminars in Cardiothoracic and Vascular Anesthesia. He is a member of the International Organization for Terminology in Anesthesia (IOTA) of the Anesthesia Patient Safety Foundation and works with that group, the International Health Terminology Standards Development Organisation (IHTDSO), and High Level Seven International (HL7) to create international standards for anesthesia terminology for electronic patient records. Ronald A. Kahn, M.D. is Professor of Anesthesiology and Surgery at the Mount Sinai School of Medicine. Alexander J. C. Mittnacht, M.D. is Associate Professor of Anesthesiology at the Mount Sinai School of Medicine and Director of Pediatric Cardiac Anesthesia at the Mount Sinai Medical Center. Andrew B. Leibowitz, M.D. is Professor of Anesthesiology and Surgery at the Mount Sinai School of Medicine and Executive Vice Chairman of the Department of Anesthesiology at the Mount Sinai Medical Center. Marc E. Stone, M.D. is Associate Professor of Anesthesiology at the Mount Sinai School of Medicine and Program Director of the Fellowship in Adult Cardiothoracic Anesthesiology at the Mount Sinai Medical Center. James B. Eisenkraft, M.D. is Professor of Anesthesiology at the Mount Sinai School of Medicine and Attending Anesthesiologist at the Mount Sinai Medical Center. Monitoring in Anesthesia and Perioperative Care Editor David L. Reich Mount Sinai School of Medicine Coeditors Ronald A. Kahn Mount Sinai School of Medicine Alexander J. C. Mittnacht Mount Sinai School of Medicine Andrew B. Leibowitz Mount Sinai School of Medicine Marc E. Stone Mount Sinai School of Medicine James B. Eisenkraft Mount Sinai School of Medicine CAMBRID GE UNIVERSIT Y PRESS Cambridge, New York, Melbourne, Madrid, Cape Town, Singapore, São Paulo, Delhi, Tokyo, Mexico City Cambridge University Press 32 Avenue of the Americas, New York, NY 10013-2473, USA www.cambridge.org Information on this title: www.cambridge.org/9780521755986  C Cambridge University Press 2011 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 2011 Printed in the United States of America A catalog record for this publication is available from the British Library. Library of Congress Cataloging in Publication data Monitoring in anesthesia and perioperative care / [edited by] David L. Reich, Ronald A. Kahn, Alexander J. C. Mittnacht, Andrew B. Leibowitz, Marc E. Stone, James B. Eisenkraft. p.; cm. Includes bibliographical references and index. ISBN 978-0-521-75598-6 (hardback) 1. Anesthesia. 2. Patient monitoring. I. Reich, David L. (David Louis), 1960– , editor. II. Kahn, Ronald A., editor. III. Mittnacht, Alexander J. C., editor. IV. Leibowitz, Andrew B., editor. V. Stone, Marc E., editor. VI. Eisenkraft, James B., editor. [DNLM: 1. Monitoring, Intraoperative – methods. 2. Anesthesia – methods. 3. Perioperative Care – methods. WO 181] RD82.M68 2011 617.9 6–dc22 2010045695 ISBN 978-0-521-75598-6 Hardback Cambridge University Press has no responsibility for the persistence or accuracy of URLs for external or third-party Internet Web sites referred to in this publication and does not guarantee that any content on such Web sites is, or will remain, accurate or appropriate. Every effort has been made in preparing this book to provide accurate and up-to-date information that is in accord with accepted standards and practice at the time of publication. Although case histories are drawn from actual cases, every effort has been made to disguise the identities of the individuals involved. Nevertheless, the authors, editors, and publishers can make no warranties that the information contained herein is totally free from error, not least because clinical standards are constantly changing through research and regulation. The authors, editors, and publishers therefore disclaim all liability for direct or consequential damages resulting from the use of material contained in this book. Readers are strongly advised to pay careful attention to information provided by the manufacturer of any drugs or equipment that they plan to use. Contents Contributors vii Foreword by Carol L. Lake x Preface xii 1 The history of anesthesia and perioperative 15 Monitoring pressure, volume, and flow in monitoring 1 the anesthesia breathing system 171 David L. Reich James B. Eisenkraft 2 Medicolegal implications of monitoring 9 16 Pulse oximetry 185 Jeffrey M. Feldman Tuula S. O. Kurki and James B. Eisenkraft 3 Validity, accuracy, and repeatability of 17 Neurologic intraoperative electrophysiologic monitoring variables 16 monitoring 199 Daniel M. Thys and Jung Kim Michael L. McGarvey and Albert T. Cheung 4 Teaching monitoring skills 27 18 Level of consciousness monitoring 218 Samuel DeMaria, Jr., Adam I. Levine, Marc J. Bloom and Yasuharu Okuda 19 Transcranial Doppler 226 5 Electrocardiography 36 Dean B. Andropoulos Alexander J. C. Mittnacht and Martin London 20 Multimodality monitoring in critically ill 6 Arterial pressure monitoring 45 neurologic patients 237 Alexander J. C. Mittnacht and Tuula S. O. Kurki Jennifer A. Frontera 7 Central venous and pulmonary artery 21 Near-infrared spectroscopy 249 catheterization 57 Dean B. Andropoulos Deborah Dubensky and Alexander J. C. Mittnacht 22 Perioperative monitoring of neuromuscular 8 Cardiac output and intravascular volume 79 function 261 Mukul Kapoor and Marc E. Stone Aaron F. Kopman 9 Gastric tonometry 95 23 Critical care testing in the operating room: Elliott Bennett-Guerrero electrolytes, glucose, acid–base, blood gases 281 Lakshmi V. Ramanathan, Judit Tolnai, and 10 Oxygen delivery, oxygen transport, and tissue Michael S. Lewis oxygen tension: critical monitoring in the ICU 98 Jayashree Raikhelkar and Peter J. Papadakos 24 Laboratory-based tests of blood clotting 291 Nathaen Weitzel, Tamas Seres, and Glenn P. Gravlee 11 Transesophageal echocardiography 105 Ronald A. Kahn and Gregory W. Fischer 25 Coagulation and hematologic point-of-care testing 308 12 Ultrasound guidance of vascular catheterization 136 Liza J. Enriquez and Linda Shore-Lesserson Andrew B. Leibowitz and Jonathan Elmer 26 Cardiac biomarkers for perioperative 13 Ultrasound guidance for regional anesthesia management 319 procedures 145 Anoushka Afonso and Eric Adler Christina L. Jeng and Meg A. Rosenblatt 27 Endocrine testing in the operating room 327 14 Respiratory gas monitoring 150 Lakshmi V. Ramanathan and Michael S. Lewis James B. Eisenkraft v  Contents 28 Temperature monitoring 331 34 Intensive care unit risk scoring 369 David Wax and Justin Lipper Adel Bassily-Marcus and Roopa Kohli-Seth 29 Fetal heart rate monitoring 337 35 Computers and monitoring: information Howard H. Bernstein management systems, alarms, and drug delivery 383 30 Pain scales 348 David Wax and Matthew Levin Jonathan Epstein, Diana Mungall, and Yaakov Beilin 31 Neurologic clinical scales 353 Jennifer A. Frontera Appendix: Monitoring recommendations for common types of surgical procedures 397 32 Postanesthesia care unit assessment scales 357 Index 405 David Bronheim and Richard S. Gist 33 Delirium monitoring: scales and assessments 360 Color plates follow page 260. Brigid Flynn and Corey Scurlock vi Contributors Eric Adler, M.D. Marc J. Bloom, M.D., Ph.D. Assistant Professor Associate Professor of Anesthesiology Department of Cardiology New York University School of Medicine Mount Sinai School of Medicine New York, NY New York, NY David Bronheim, M.D. Anoushka Afonso, M.D. Associate Professor Anesthesia Resident Department of Anesthesiology Department of Anesthesiology Mount Sinai School of Medicine Mount Sinai School of Medicine New York, NY New York, NY Albert T. Cheung, M.D. Dean B. Andropoulos, M.D., M.H.C.M. Professor Chief of Anesthesiology Department of Anesthesiology and Critical Texas Children’s Hospital Care Professor, Anesthesiology and Pediatrics University of Pennsylvania School of Medicine Baylor College of Medicine Philadelphia, PA Houston, TX Samuel DeMaria, Jr., M.D. Adel Bassily-Marcus, M.D. Instructor in Anesthesiology Assistant Professor Department of Anesthesiology Department of Surgery Mount Sinai School of Medicine Division of Critical Care Medicine New York, NY Mount Sinai School of Medicine Deborah Dubensky, M.D. New York, NY Department of Anesthesiology Yaakov Beilin, M.D. University of Rochester Medical Center Professor Rochester, NY Department of Anesthesiology James B. Eisenkraft, M.D. Department of Obstetrics, Gynecology, and Reproductive Professor Science Department of Anesthesiology Mount Sinai School of Medicine Mount Sinai School of Medicine New York, NY New York, NY Elliott Bennett-Guerrero, M.D. Jonathan Elmer, M.D. Professor and Director of Perioperative Clinical Research Clinical Fellow Duke Clinical Research Institute Department of Emergency Medicine Duke University Medical Center Brigham and Women’s Hospital Durham, NC Boston, MA Howard H. Bernstein, M.D. Liza J. Enriquez, M.D. Associate Professor Fellow Department of Anesthesiology Department of Anesthesiology Mount Sinai School of Medicine Montefiore Medical Center New York, NY Bronx, NY vii  Contributors Jonathan Epstein, M.D., M.A. Jenny Kam, M.D. Attending Anesthesiologist Chief Resident St. Luke’s–Roosevelt Hospital Center Department of Anesthesiology New York, NY Mukul Kapoor, M.D. Jeffrey M. Feldman, M.D., M.S.E. Senior Adviser Associate Professor of Clinical Anesthesiology Anaethesiology and Cardiothoracic Anaesthesiology Department of Anesthesiology and Critical Care Command Hospital Medicine Lucknkow, India University of Pennsylvania School of Medicine Jung Kim, M.D. Division Chief, General Anesthesia Department of Anesthesiology Children’s Hospital of Philadelphia St. Luke’s–Roosevelt Hospital Center Philadelphia, PA New York, NY Gregory W. Fischer, M.D. Roopa Kohli-Seth, M.D. Associate Professor of Anesthesiology and Cardiothoracic Assistant Professor Surgery Department of Surgery Director of Adult Cardiothoracic Anesthesia Division of Critical Care Medicine Mount Sinai School of Medicine Mount Sinai School of Medicine New York, NY New York, NY Brigid Flynn, M.D. Aaron F. Kopman, M.D. Assistant Professor Professor of Clinical Anesthesiology Department of Anesthesiology Weill Cornell Medical College Mount Sinai School of Medicine New York, NY New York, NY Tuula S. O. Kurki, M.D., Ph.D. Jennifer A. Frontera, M.D. Head of the Preoperative Clinic Assistant Professor Department of Anesthesia and Intensive Care Departments of Neurology and Neurosurgery Helsinki University Central Hospital Mount Sinai School of Medicine Helsinki, Finland New York, NY Andrew B. Leibowitz, M.D. Richard S. Gist, M.D. Professor of Anesthesiology and Surgery Professor Department of Anesthesiology Department of Anesthesiology Mount Sinai School of Medicine Mount Sinai School of Medicine New York, NY New York, NY Matthew Levin, M.D. Glenn P. Gravlee, M.D. Mount Sinai School of Medicine Professor New York, NY Department of Anesthesiology University of Colorado Denver Adam I. Levine, M.D. Aurora, CO Associate Professor Department of Anesthesiology Christina L. Jeng, M.D. Mount Sinai School of Medicine Assistant Professor of Anesthesiology and Orthopaedics New York, NY Department of Anesthesiology Michael S. Lewis, M.D. Mount Sinai School of Medicine Director of Transfusion Medicine and Histology New York, NY Assistant Professor of Pathology Ronald A. Kahn, M.D. University of Southern California, Keck School of Medicine Professor of Anesthesiology Attending Pathologist Department of Anesthesiology West Los Angeles VA Hospital Mount Sinai School of Medicine Mount Sinai School of Medicine New York, NY Los Angeles, CA viii  Contributors Justin Lipper, M.D. Department of Anesthesiology Mount Sinai School of Medicine Mount Sinai School of Medicine New York, NY New York, NY Martin London, M.D. Meg A. Rosenblatt, M.D. Professor of Clinical Anesthesia Professor University of California, San Francisco Department of Anesthesiology San Francisco, CA Mount Sinai School of Medicine New York, NY Michael L. McGarvey, M.D. Assistant Professor Corey Scurlock Department of Neurology Assistant Professor University of Pennsylvania Departments of Anesthesiology and Cardiothoracic Philadelphia, PA Surgery Alexander J. C. Mittnacht, M.D. Mount Sinai School of Medicine Associate Professor New York, NY Department of Anesthesiology Mount Sinai School of Medicine Tamas Seres, Ph.D. New York, NY Associate Professor Department of Anesthesiology Timothy Mooney, MD University of Colorado Denver Fellow Aurora, CO Duke University Medical Center Durham, NC Linda Shore-Lesserson, M.D. Professor of Anesthesiology Diana Mungall, B.S. Montefiore Medical Center Department of Anesthesiology Bronx, NY Mount Sinai School of Medicine New York, NY Marc E. Stone, M.D. Yasuharu Okuda, M.D. Associate Professor Associate Clinical Professor Department of Anesthesiology Department of Emergency Medicine Mount Sinai School of Medicine Mount Sinai School of Medicine New York, NY New York, NY Daniel M. Thys, M.D. Peter J. Papadakos, M.D., F.C.C.M. Chairman Emeritus Professor of Anesthesiology, Surgery, and Neurosurgery Department of Anesthesiology Director, Division of Critical Care Medicine St. Luke’s–Roosevelt Hospital Center University of Rochester New York, NY Rochester, NY Jayashree Raikhelkar, M.D. Judit Tolnai, B.S. Assistant Professor Department of Pathology Departments of Anesthesiology and Cardiothoracic Surgery Mount Sinai School of Medicine Mount Sinai School of Medicine New York, NY New York, NY David Wax, M.D. Lakshmi V. Ramanathan, Ph.D. Assistant Professor Assistant Professor Department of Anesthesiology Department of Pathology Mount Sinai School of Medicine Mount Sinai School of Medicine New York, NY Director, Chemistry, Endocrinology, Stat Lab, and Point of Care Testing Nathaen Weitzel, M.D. Mount Sinai Medical Center Assistant Professor New York, NY Department of Anesthesiology David L. Reich, M.D. University of Colorado Denver Professor and Chair of Anesthesiology Aurora, CO ix  Foreword Carol L. Lake Training and practicing the specialty of anesthesiology, and devices or techniques to monitor parameters currently judged specifically cardiac anesthesia, during the last three decades of difficult to assess, such as intraoperative, global cerebral or the 20th century provides a unique perspective from which renal function, being adequately supported? Dr. Reich and his to address the state of clinical monitoring for health care. many distinguished contributing authors provide a compre- The advent and growth of sophisticated physiologic monitor- hensive practical review of these questions while preparing the ing clearly advanced the anesthesiology subspecialty of cardiac reader to confront these future monitoring challenges. anesthesia, and vice versa. Likewise, it seems especially prudent Information overload occurs when there are many parame- that Dr. David L. Reich, a cardiac anesthesiologist, and many ters to observe, necessitating the provision of alarm systems, set of the chapter authors, represent the subspecialty of cardiac to indicate when a particular parameter or device is outside set anesthesia. limits. However, these same alarms do not always indicate true From using a manual blood pressure cuff, precordial stetho- life-threatening emergencies. Attending to false alarms adds to scope, and a finger on the pulse to the current American Soci- the workload and encourages ignoring them, obviously to the ety of Anesthesiologists standards of monitoring the patient’s detriment of the patient if the alarm is not false. Ways to pri- oxygenation, ventilation, circulation, and temperature continu- oritize and display alarms, and to prevent unnecessary alarms, ally (usually with pulse oximetry, electrocardiogram, end-tidal will continue to be the subject of research until user-friendly, carbon dioxide, temperature, inspired/expired anesthetic gases, ergonomic, common anesthesia workstations exist. and automated blood pressure cuff during general anesthesia) Reliance on alarms may also encourage inattention by the was the great leap forward in perioperative monitoring in the person providing anesthesia or critical care. Although a recent 20th century. Similarly, the plethora of devices developed dur- single-institution study demonstrated that intraoperative read- ing the past century to allow monitoring of depth of anesthe- ing and nonpatient-related conversation did not adversely sia, respiratory compliance, ventricular contractility, coagula- affect recognition of a randomly illuminated alarm light tion, tissue oxygenation, and blood flow, rather than only basic (Slagle JM, Weinger MB. Effects of intraoperative reading on cardiovascular parameters such as heart rate and blood pres- vigilance and workload during anesthesia care in an academic sure, is truly amazing progress. The past and present of phys- medical center. Anesthesiology 2009;110:275–283), recognizing iologic monitoring are represented in the history chapter and an impending disaster before the alarm sounds may save pre- the chapters on equipment, procedures, techniques, and tech- cious seconds, and those seconds count if you or your loved one nologies, respectively, in this book. Unfortunately, at the present is the anesthetized or critically ill patient. time, many of the critical incidents during anesthesia still result The training, retraining, and ongoing evaluation of com- from inadequate or incomplete monitoring of the patient, the petence of the anesthesia team to use complex and sophisti- anesthesia machine, or the patient–machine interface. cated monitoring devices remains an educational conundrum. What is the future for monitoring in health care in general Although textbooks and lectures continue to be the mainstay and anesthesiology, critical care, and pain management in of health care educational material, interactive computer pro- particular? With the miraculous advances in clinical moni- grams; standardized patients; part-task trainers; human patient toring have come associated challenges that are addressed in simulators mimicking neonates, children, and adults; and real- this book. How can information overload from monitors be istic simulation laboratories configured to be operating rooms, minimized? How are trainees educated and trained in mul- intensive care units, emergency departments, or patient rooms tiple monitoring techniques? How can practitioners beyond appear likely to become the major training and examination training maintain their skills with infrequently used, complex venues in the 21st century. A simulation laboratory is an ideal monitors? How will future anesthesiologists and intensivists environment to learn to use monitoring devices and techniques know whether a new device or monitoring technique is useful and is particularly applicable to demonstration of competence and reliable? Has a cost–benefit analysis of a specific monitor with monitoring techniques. demonstrated effectiveness? Similar demanding questions need Are there hazards to the extensive use of monitoring? to be answered. Finally, is the ongoing research to develop new Possibly. Could the increased technology of monitoring occur at x  Foreword the expense of clinical acumen? We have already seen that over- Despite all the extensive and sophisticated devices and tech- reliance on monitors leads to both amusing and deleterious sit- niques described in this book, there is nothing at present uations, such as the pronouncement of ventricular fibrillation that can replace the vigilance of a professional anesthesia or by a new anesthesiology resident when an electrocardiograph intensive care team providing the human-to-human interaction lead falls off the patient or the inability to assess anesthetized essential to patient safety and well-being in operating rooms, patient well-being when electrical power is interrupted in a intensive care units, or the myriad venues in which patients developing country or following a disaster. Could sophisticated receive general anesthesia or its equivalents. As Dr. Reich’s book 21st-century perioperative monitoring expose the specialty of aptly illustrates, 21st-century monitoring for anesthesiology, anesthesiology to eventual substitution by robots with artificial pain management, and critical care must focus on striking the intelligence? Probably not, because the monitors still lack the optimal balance among such factors as patient safety, cost, clini- completeness, continuousness, and adaptability to human nat- cal outcomes, innovation, and complexity. However, the patient, ural variation in perioperative situations. not the monitor, must always come first! xi  Preface Monitoring in Anesthesia and Perioperative Care follows the tra- Patient monitoring in anesthesia and perioperative care dition of previous texts that document the current art and sci- has changed drastically since the specialty of anesthesiology ence of perioperative patient monitoring. Additionally, the text emerged in the 19th century. The pace of that change has accel- addresses the systems-based practice issues that drive the highly erated in recent decades as one sees in the preceding texts on regulated health care industry of the early 21st century. The ini- the subject, which are snapshots of the monitoring practices of tial chapters cover the concepts of history, medicolegal implica- their eras. The earliest of those texts that I located illustrated tions, validity of measurement, and education. The core of the an important juncture in the art and science of patient mon- book addresses the many monitoring modalities. To the extent itoring. In these two quotes from the preface of Dornette and possible, each chapter is organized in a systematic fashion to Brechner’s Instrumentation in Anesthesiology (Philadelphia: Lea describe: & Febiger, 1959), we see the point in anesthesia history at which the emphasis shifted from direct patient observation to reliance 1. Technical concepts: How does it work? on mechanical instrumentation: 2. Parameters monitored: What information do you get from it? [The anesthesiologist] feels the pulse and rebreathing bag to determine rate, 3. Evidence of utility: Is there evidence that it makes a rhythm and volume of the pulse waves and respiratory efforts. He sees the difference in outcome? eye signs and thoracic excursions to assess depth of anesthesia. He hears the 4. Complications: What harm can it cause? sound generated by compression of the brachial artery during auscultation 5. Credentialing and monitoring standards: What is the of the blood pressure. He smells the anesthetic atmosphere to determine educational or credentialing process, if any? the approximate concentration of ether or cyclopropane. He tastes the fluid 6. Practice guidelines: When should/must I use it? dripping from the epidural needle to differentiate bitter procaine from taste- less cerebrospinal fluid. Ultrasonic guidance of invasive catheterization and regional [Instrumentation] increases the perceptibility of our senses, and also allows anesthesia are included as monitoring concepts. The next group the study of physiologic signals not capable of being detected by these senses. of chapters addresses scales and assessments that are increas- ingly evidence-based documentation standards. Finally, elec- The monitoring texts in more recent years, including those tronic health records, alarm systems, and automated medica- edited by Lake, Saidman and Smith, Blitt and Hines, Graven- tion delivery systems complete the body of the text. A table in stein and colleagues, and Dorsch and Dorsch, have chronicled the appendix is intended to help residents and other anesthesia these continuing changes in both instrumentation and stan- care providers know the typical monitoring modalities that are dards. Their erudition and eloquence set a high standard. The chosen for major categories of operations. current publication is intended to continue the tradition of The target audience for this text is medical students, anes- anesthesiologists as the leaders in patient monitoring education thesia residents, Fellows, nurse anesthetists, anesthesia assis- and standards creation. tants, and anesthesia and critical care practitioners who are acquiring or updating their knowledge of patient monitoring David L. Reich, M.D. during anesthesia and the perioperative period. There is signifi- Professor and Chair cant overlap with critical care monitoring, and the intensive care Department of Anesthesiology physician will find nearly all concepts of critical care monitor- Mount Sinai School of Medicine ing to be covered. New York, NY xii  Chapter The history of anesthesia and perioperative 1 monitoring David L. Reich Introduction and explained in his surgical lectures that, in his opinion, chlo- roform was safer than ether anesthesia if it was administered The discoveries that facilitated patient monitoring in the peri- properly. The key, however, to proper administration was mon- operative period occurred long before the introduction of clin- itoring the patient’s respiration.5 ical anesthesia. Respiratory patterns had been described since Joseph Lister, M.D., the founder of the principles of anti- antiquity. The rise of scientific methods in Renaissance Europe sepsis in surgery, was an eminent surgeon in Scotland and led to the initial experiments in hemodynamics – specifically, the United Kingdom from the 1850s through the 1890s. He animal experiments demonstrating that blood flows under protested against palpation of the pulse as “a most serious mis- pressure. The earliest source that cited correct observations of take. As a general rule, the safety of the patient will be most pro- arterial and venous flow and pressures was William Harvey’s moted by disregarding it altogether, so that the attention may be De Motu Cordis, published in 1628.1 In the following century, devoted exclusively to the breathing.”6 Dr. Lister’s instruction Stephen Hales offered the first quantification of arterial blood to the senior students who served as his anesthetists was “that pressure measured in the horse.2 The first cardiac catheteriza- they strictly carry out certain simple instructions, among which tion was performed by Claude Bernard in 1844.3 is that of never touching the pulse, in order that their attention Soon after the introduction of clinical general anesthesia by may not be distracted from the respiration.” His airway man- W. T. G. Morton in 1846 and John Snow in 1847, the need to agement strategy included “the drawing out of the tongue” and monitor patients was recognized by the leaders of the new spe- he believed that the services of special anesthetists were unnec- cialty. The first documented death under chloroform anesthesia essary if simple routines were followed by his assistants while (that of fifteen-year-old Hannah Greener in 1848) led the early administering chloroform. practitioners to highlight the importance of monitoring simple Joseph Thomas Clover, M.D., was the leading clinical anes- vital signs – respiration, pulse, and skin color. Since that time, thetist in Victorian England during his professional life, from patient safety concerns have invariably driven the development the beginning of his anesthesia practice in 1846 until his death of monitoring modalities and standards in perioperative mon- in 1882. In 1864, the Royal Medico-Chirurgical Society estab- itoring practice. This chapter recounts important milestones of lished a committee to investigate chloroform fatalities, and as an perioperative patient monitoring and the historical events and expert assistant to that group, Dr. Clover described his innova- clinical developments that influenced them. tions in apparatus and animal experimentation with anesthet- ics. He strongly advised that the pulse be continuously observed during an anesthetic and that irregularities such as a diminution Early advocacy of monitoring the pulse should alert the anesthetist to discontinue the anesthetic. He and respiration also advised monitoring the pulse continuously while adminis- As news of the Boston public demonstration reached London tering an anesthetic. “If the finger be taken from the pulse to do late in 1846, John Snow, M.D. personally adopted the tech- something else, I would give a little air.”7 James Young Simpson, nique, publishing his series of eighty anesthetized patients, M.D., also voiced caution during the administration of chloro- ranging in age from children to octogenarians, in Inhalation form when snoring ensued and the pulse became “languid.”8 of the Vapour of Ether in Surgical Operations. He mentioned With continuing deaths associated with chloroform use, a the customary monitoring under anesthesia to include respi- group led by Edward Lawrie formed a commission in Hyder- ration depth and frequency, muscle movements, skin color, abad, India to investigate causes. In 1888, the first commission and stages of excitation or sedation. Although the pulse was report asserted the safety of chloroform anesthesia.9 In 1889, continually palpated, its characteristics were not considered the Second Hyderabad Chloroform Commission concluded worth studying.4 By 1855, the Edinburgh surgeon James Syme, that chloroform deaths were related to respiratory depression M.D., lectured on the importance of monitoring respiration and not a directly injurious effect on the heart. The commission 1  Monitoring in Anesthesia and Perioperative Care reported that anesthetists should be guided entirely by respi- The anesthesia record ration, as pupil size and pulse were not significant enough to Once the idea that monitoring patients under anesthesia was monitor.10,11 clinically useful and early tools were developed to do so, the anesthetic record could not be far behind. B. Raymond Fink, M.D., credits the first anesthetic record to A. E. Codman, M.D., at the Massachusetts General Hospital in 189416 (Figure 1.2). Auscultation of heart tones Dr. Codman’s chief, F. B. Harrigan, M.D., recommended record- The earliest clinical account of auscultation in the operat- ing the patient’s pulse during an anesthetic. This practice was ing room was reported in 1896 by Robert Kirk, M.D., of encouraged by Dr. Cushing, who published a classic paper in the Glasgow Western Infirmary. An ordinary binaural stetho- 1902 reproducing an actual patient’s anesthetic record.17 Dr. scope lengthened by Indian rubber tubing was first used. Later, Cushing’s initiatives were not accepted easily, and opponents to 200 patients anesthetized with chloroform were auscultated the newer devices to measure temperature, pulse, blood pres- using a “phonendoscope” with timing of heart rate and rhythm sure, and the auscultation of the heart were castigated by an by a watch.12 Dr. Kirk was involved at the time with the Glas- editorial in the British Medical Journal claiming that “by such gow Committee on Anesthetic Agents and saw the stethoscope methods we pauperize our senses and weaken clinical acuity.”18 as a clinical research tool to assess the effects of chloroform on cardiac physiology. Charles K. Teter, D.D.S., described the benefits of using Indirect measurement of arterial a stethoscope during anesthesia, especially in poor-risk blood pressure patients.13 He praised the convenience of the flat Kehler In 1901, during a visit to Italy, Harvey Cushing met Scipione stethoscope, which “will usually stay without being held” on Riva-Rocci, who, a few years earlier, had developed a practical the precordium. When necessary, adhesive tape prevented its sphygmomanometer for measuring blood pressure indirectly.19 being dislodged. Dr. Teter praised the stethoscope because Subsequently, Cushing recommended the routine use of this “uninterrupted information will be given to any and all sphygmomanometer to determine blood pressure during anes- change[s] in the heart beat and respiration.” He expressed his thesia.20 Because the return-to-flow method was employed by feeling of confidence when “every variation of heart sound is palpation of the radial pulse, only the systolic pressure could at once discernable, and what might be serious complications be determined. Furthermore, this was inaccurate, as the cuff can be averted by the premonitory symptoms thus made used was a bicycle inner tube, which gave excessively high values manifest.”13 owing to the ratio of the region of compression to arm circum- The strong advocacy of routine, continuous monitoring of ference. At that time, however, normal values for systolic blood cardiac and respiratory sounds under anesthesia by Harvey pressure were unknown and the instrument provided the first Cushing, M.D., gave impetus to the widespread clinical use of clinical example of following trends of blood pressure change intraoperative auscultation14 (see Figure 1.1). An esophageal during surgery. stethoscope was described in 1893 by Solis-Cohen15 for diag- In 1905, Korotkoff described the sounds heard when flow nostic purposes, but it was not adopted as a routine monitoring occurs distal to the deflating cuff.21 This, together with the use of technique until nearly seventy-five years later. a wider cuff advocated by von Recklinghausen,22 allowed more accurate determination of blood pressure and is the basis of cur- rent auscultatory blood pressure monitoring. Further advances in the indirect measurement of blood pressure largely involved the development of alternative means of “sensing” systolic and diastolic points and automating the process. In 1931, von Recklinghausen23 described a semiautomated device for measuring blood pressure, known as an oscil- lotonometer. A double-cuff system was used, with the proximal cuff occluding the artery and the distal cuff acting as the sen- sor to detect the onset of arterial pulsations. The introduction of ultrasound into clinical medicine in the 1940s allowed the application of the Doppler principle to detect blood flow24 and movement of the arterial wall under the distal edge of the sphyg- momanometer cuff.25 The Arteriosonde (Roche) used ultra- sound at 3 mHz that reflected off the vibrating arterial wall, which the practitioner heard as an electronically conditioned Figure 1.1. Early stethoscopes used for intraoperative monitoring are displayed. (Courtesy of the Wood Library-Museum of Anesthesiology, Park audible signal. The device was accurate and found its greatest Ridge, IL) application for measurement of blood pressure in infants.26 The 2  Chapter 1 – The History of Anesthesia and Perioperative Monitoring Figure 1.2. One of the first known anesthesia records is reproduced. (Courtesy of the Wood Library-Museum of Anesthesiology, Park Ridge, IL) desire for more automated and rapid acquisition of noninvasive created a school that trained physicians, nurses, and orderlies blood pressure led to the development of automated devices has in open-drop ether.29 He prepared a chart of his version of the allowed frequent estimation of indirect blood pressure. The first signs and stages of ether anesthesia, the most common agent in wide commercial success was the Dinamap (Critikon), which use at the time because of its wide margin of safety (Figure 1.3). essentially was an automated oscillotonometer. The instrument Armed with their charts, the trainees went out to nearby hospi- was simple to use and produced accurate results.27 tals to work on their own, as Dr. Guedel made weekly motorcy- cle rounds to check on his trainees at the six hospitals for which Eye signs of anesthesia depth he was responsible.30 Although Snow and other early leaders of the specialty Direct measurement of arterial described the monitoring of depth of anesthesia, the individual given greatest credit for standardizing the process was Arthur blood pressure Guedel, M.D. The eye signs of ether anesthesia were the most Poiseuille, in 1828, described the mercury manometer.31 In significant contribution to his schematic approach to identi- 1847, Karl Ludwig made use of Poiseuille’s device and applied fying signs of anesthesia.28 The eye signs included the activity it to his invention of the kymograph.32 A column of mercury of motor muscles of the eyeball, pupillary dilation, and, later, on the kymograph moved, and thus directed a floating nee- the eyelid reflex. The eyelid reflex was tested by gently rais- dle against a moving drum. This device allowed animal hemo- ing the upper eyelid with the finger. If the reflex was present, dynamic physiology to be recorded continuously for research the eyelid would attempt to close at once or within a few sec- purposes. The application to humans, however, was limited by onds. The corneal and eyelash reflexes known today were not problems of vascular access and control of bleeding and infec- mentioned.29 tion. Almost one century later, direct recording of arterial blood The setting for these contributions was the complete lack of pressure continued to be difficult, even though problems of sep- trained anesthesia specialists when the United States entered sis and coagulation were solved. World War I.30 Dr. Guedel experienced a crush of casualties The discovery of plastic “nonthrombogenic” sterile tubing from a major battle, where his staff of three physicians and one and its medical applications occurred in 1945–46. In 1949, Lyle dentist ran as many as forty operating room tables at a time. Peterson and Robert Dripps described the technique of percu- He concluded that additional anesthesia care providers would taneous placement of a plastic catheter for continuous measure- have to be trained quickly to meet this overwhelming need and ment of arterial blood pressure during anesthesia and surgery.33 3  Monitoring in Anesthesia and Perioperative Care Figure 1.3. One version of Guedel’s chart demon- strating stages of ether anesthesia. (Courtesy of the Wood Library-Museum of Anesthesiology, Park Ridge, IL) The value of this measurement was widely recognized, but the The first prospective study of the practical use of the elec- technique remained unpopular. The recording equipment was trocardiograph (ECG) for monitoring patients in the operat- impractical and too expensive. ing room was reported in 1922. Lennox, Graves, and Levine36 The technique of surgical cut-down was used to gain access studied fifty operations performed on forty-nine patients at to peripheral arteries during cardiac surgery in the 1950s. the Peter Bent Brigham Hospital in Boston. The monitoring In 1960, the catheter-over-the-needle technique was intro- method was onerous. The electrocardiographer was summoned duced, and the wide medical application of polytetrafluoroethy- by a buzzer in the operating room at the beginning and end lene (PTFE; Teflon, Dupont, Inc.) Teflon made possible con- of the operation and during critical moments in the opera- venient percutaneous access, leading to easier and smoother tion. ECG tracings were produced by a string galvanometer, percutaneous placement of cannulae for continuous moni- at average intervals of 2.5 minutes. For a permanent record, toring of arterial blood pressure by surgeons, anesthesiolo- photographic paper had to be exposed to light. The heart rate gists, and intensive care specialists. Simultaneous technological calculated from the ECG tracings was much higher than the advances in pressure transducers, continuous flush systems, and count of the anesthetist. The most marked discrepancies usu- transistor-based display and recording equipment made inva- ally occurred during induction of anesthesia, when the pulse sive arterial monitoring commonplace. rate was taken by a nurse from the ward. Abnormalities of con- duction (displacement of pacemaker) were found in 15 (30%) of the cases and 11 cases developed premature beats, seven of them The electrocardiogram in the operating room ventricular in origin. None of these premature beats was noted In 1918, Heard and Strauss34 reported two cases of atrioven- by the anesthetist. Analysis of the patients’ characteristics, type tricular rhythm, one of which occurred immediately following of surgery, and type of anesthesia failed to demonstrate predis- ether anesthesia. They reported that “no other cases of nodal posing factors apart from alterations in vagal tone. rhythm have been observed by us in a series of 21 cases in which The value of the electrocardiogram during surgery was electrocardiographic records have been taken during anesthe- demonstrated by further similar studies.37–39 The intermittent sia.” No further details were given. Levine35 reported two cases nature of the recording and the inevitable delay in develop- of paroxysmal atrial tachycardia under ether anesthesia, docu- ing ECG tracings on photographic paper, however, limited mented by electrocardiography. the usefulness of these observations for diagnosis and therapy. 4  Chapter 1 – The History of Anesthesia and Perioperative Monitoring Direct-writing ECG recorders eliminated the delay associated than their enemies became hypoxic (without cabin pressuriza- with processing films but were impractical for obtaining con- tion), lost consciousness, and crashed. Physicist Glen Millikan tinuous records.40 (1906–1947) developed oximetry in 1940 as a pilot warning In 1952, Himmelstein and Scheiner described a cardiotach- device, but the technology became practical only when pulse oscope, which permitted continuous display of the ECG on a oximetry was introduced in approximately 1980. The polio epi- cathode ray screen.41 The heart rate, obtained by measuring the demics drove the development of artificial ventilation, with the time interval between successive beats, appeared as a moving need for carbon dioxide analysis to guide the ventilation of a line on the calibrated screen of a cathode ray tube. A direct writ- paralyzed patient. The mid-20th-century advances in the use ing cardiograph could be attached to the instrument to obtain of hypothermia and cardiopulmonary bypass necessitated fre- permanent records. quent monitoring of oxygenation and acid–base status.53 With the advent of continuous ECG monitoring devices, Severinghaus built a cuvette for the carbon dioxide elec- the routine use of the ECG to detect abnormalities of rhythm trode and mounted it in a 37◦ C water bath. His modifications and rate became practical, albeit too expensive for routine use. of Stow’s invention cut analysis time from an hour to two min- Several reviews and studies42,43 documented the type and inci- utes. Clark had built a successful bubble-type blood oxygena- dence of dysrhythmias that could occur during anesthesia. Lead tor to perfuse livers.54 To measure PO2 in the oxygenator, he II was usually monitored because the axis paralleled the normal turned to polarography. In 1954, Clark made an electrically P wave vector, facilitating easy recognition of dysrhythmias. The insulated polarographic sensor with cathode and reference elec- application of the ECG to detect myocardial ischemia during trode combined, permitting it to work in either air or liquid. anesthesia was first proposed by Kaplan and King.44 In patients With Clark’s approval, Severinghaus used his electrode and undergoing stress tests, Blackburn45 had previously found that his modification of Stow’s carbon dioxide electrodes in a blood the majority of ischemic episodes could be detected by precor- gas analyzer. Severinghaus displayed the first blood PO2 and dial lead V5 of a 12-lead electrocardiogram. Kaplan46 demon- PCO2 analyzer at the fall American Society of Anesthesiologists strated successful use of a modified CM5 lead in anesthetized meeting in 1957.55 The addition of a pH electrode completed the patients. This lead was practical with three-lead ECG systems, modern arterial blood analysis device. then in common clinical use in the operating room. In the 1960s, with the advent of oxygen therapy and posi- tive pressure ventilation of premature infants, it became appar- Central venous and pulmonary ent that excessive oxygenation was associated with blindness. Transcutaneous blood gas monitoring was developed primar- artery catheterization ily to avoid oxygen-induced retinopathy of prematurity. A Werner Forssmann is credited with being the first person to skin surface oxygen electrode heated to 44◦ C accurately moni- pass a catheter into the heart of a living person47 , using him- tored PaO2.56 Severinghaus further developed a transcutaneous self as the subject. He passed a ureteral catheter through one PCO2 electrode57 and combined oxygen and carbon dioxide of his left antecubital veins, guiding it by fluoroscopy into electrodes under a single membrane.58 his right atrium, and then confirming the position by chest roentgenogram. In 1930, Klein reported eleven catheterizations of the right side of the heart, including catheterization of the Neuromuscular monitoring right ventricle and measurement of cardiac output in humans, At the time when d-tubocurarine (1942), alcuronium (1964), using Fick’s principle.48 In the 1940s, catheterization of the right and pancuronium (1967) were the staple relaxants, Christie side of the heart began to be used to investigate problems of and Churchill-Davidson59 and Katz60 first popularized the use cardiovascular physiology by Cournand,49 who later received of peripheral nerve stimulation in the mid-1960s (the Block- the Nobel prize (together with Forssmann) for his pioneering Aid monitor) to evaluate neuromuscular function. This device efforts. applied a twitch (every four seconds) or tetanic stimulation In 1947, Dexter50 and Werko51 reported on oxygen satura- (30 Hz on demand). These investigators popularized the obser- tion in the pulmonary artery and demonstrated, for the first vation and recording of adductor responses from the thumb, time, the value of the pulmonary artery wedge pressure in elicited via the ulnar nerve at the wrist.60 Shortly thereafter, estimating left atrial pressure. In 1970, a balloon-tipped flow- Ali and others (1971)61 introduced train-of-four (TOF) stim- guided catheter technique was introduced by Swan and Ganz, ulation, and Lee (1975)62 further popularized this technique by making possible the use of the catheter outside the catheteriza- quantifying and correlating depth of blockade (percent twitch tion laboratory in intensive care units and operating rooms.52 inhibition) according to the TOF count. The TOF technique has remained the most useful method Monitoring of oxygenation, blood gases, of evaluation of neuromuscular function in clinical anesthesia practice for more than thirty years because of its simplicity and and acid–base status ease of evaluation and because the stimulus pattern creates its As related by John W. Severinghaus, respiratory physiology own internal standard each time the response is evaluated; that became important when World War II pilots trying to fly higher is, the strength of the fourth response is simply compared with 5  Monitoring in Anesthesia and Perioperative Care that of the first without the need for establishment of a baseline tilation. He concluded that these seven, as well as one other, in prior to the administration of neuromuscular blocking drugs.63 which oxygen was discontinued inadvertently, would have been prevented by “safety monitoring.” Of the next 300,000 anesthet- ics after the institution of the Harvard capnography and pulse Safety-driven monitoring standards oximetry monitoring standards in 1985, there were no major As recounted by Ellison Pierce, the latest historical drivers of preventable intraoperative anesthesia injuries. improvements in anesthesia monitoring were a combination of The evidence-based monitoring standards and guidelines media attention to anesthetic deaths and a malpractice insur- that emerged in the 1980s and 1990s have changed the prac- ance rate crisis of the 1970s and 1980s.64 The field of anes- tice of anesthesia and evolved over time. The ASA and peer thesia safety research was advanced in 1978 with the publica- organizations embraced evidence-based standards and prac- tion of Jeffrey Cooper’s first paper describing critical incident tice parameters related to basic monitoring standards, trans- analysis applied to anesthesia.65 Cooper stated, “Factors associ- esophageal echocardiography, and pulmonary artery catheteri- ated with anesthetists and/or factors that may have predisposed zation (http://www.asahq.org/publicationsAndServices/sgstoc. anesthetists to err have, with a few exceptions, not been previ- htm, accessed February 7, 2011). ously analyzed. Furthermore, no study has focused on the pro- In conclusion, the history of anesthesia monitoring is a cess of error – its causes, the circumstances that surround it, or fascinating prelude to the remainder of this text. A remark- its association with specific procedures, devices, etc. – regard- able group of perioperative physicians who were dedicated to less of final outcome.” improving patient outcomes persevered to advance the spe- Data for this first critical incident technique study were cialty, despite resistance from peers who did not share their obtained from 47 interviews of staff and resident anesthesiol- vision. The gradual advance in the quality and sophistication ogists. In a follow-up paper published in 1984, the database of instrumentation and the regression of clinician observations was enlarged to include 139 practitioners and 1089 descrip- of physical signs is another theme that is remarked on by every tions of preventable critical incidents.66 Cooper proposed cor- chronicler of anesthesia history. The recent decades have also rective strategies to lessen the likelihood of an incident occur- brought the rise of standards in monitoring practice. The his- ring, including using appropriate monitoring instrumentation tory of anesthesia clearly shows how safer anesthesia practices and vigilance.67 have arisen through improved patient monitoring. The lesson to Major mortality studies have come from the United King- be taken from this chapter is that we still have the capacity for dom, where Lunn and associates established a confidential, further improvements in perioperative patient safety, and that anonymous system to report anesthesia deaths associated with we will remember most clearly those perioperative physicians surgery. Their initial report was published in 1982, and anesthe- who advance that goal. sia was considered partly or totally causative of mortality in one or two cases per 10,000 and to be totally causative in nearly 1 per 10,000. Their monitoring-related findings were that that large Acknowledgments numbers of patients did not have blood pressure recorded intra- The author is indebted to Selma Harrison Calmes, M.D., operatively and did not have intraoperative monitoring with the Lydia A. Conlay, M.D., Ph.D., Doris K. Cope, M.D, James C. electrocardiogram.68 Erickson III, M. Ellison C. Pierce, Jr., M.D., John Severing- The Closed Claims Project of the American Society of Anes- haus, M.D., and George Silvay, whose writings served as the thesiologists (ASA) found that adverse respiratory events con- source material for this chapter. Additionally, the staff of the stituted the single largest class of injury, some 35 percent of Wood Library–Museum of Anesthesiology, Park Ridge, IL, were the total.69 The first three mechanisms of adverse respiratory instrumental in providing research and support. events were inadequate ventilation (38%), esophageal intuba- tion (18%), and difficult intubation (17%), and the majority of respiratory claims were lodged before widespread adoption of References 1. Harvey W. De Motu Cordis (translated by Chauncey Leake), pulse oximetry and capnography. The reviewers concluded that Tercentenary ed. Springfield, IL: Charles C. Thomas, 1928. better monitoring would have prevented adverse outcomes in 2. Hales S. An account of some hydraulic and hydrostatical three-quarters of the respiratory claims, compared with only experiments made on the blood and blood vessels of animals. In around 10 percent in the nonrespiratory cases. Willus FA, Keyes RE, eds. Cardiac Classics. St. Louis: Mosby, There is indirect evidence that the advent of ASA basic mon- 1941;I:131–155. itoring standards has diminished the incidence of adverse respi- 3. Bernard C. Leçon sur la chaleur animale. Paris: Libraire J-M. ratory events in anesthesia. Eichhorn reviewed 1 million anes- Bailliere et Fils, 1876. 4. Snow J. On the Inhalation of the Vapour of Ether in Surgical thetics administered to ASA physical status 1 and 2 patients Operations. London: John Churchill, 1847; reproduced by Lea & at the various Harvard hospitals between 1976 and 1985, and Febiger, Philadelphia, 1959. noted 11 major intraoperative anesthesia accidents (2 cardiac 5. Syme WS. The Scottish chloroform legend – Syme and Simpson arrests, 4 cases of severe brain damage, and 5 deaths).70 The as practical anesthetists. In Essays on the First Hundred Years of most common cause (7 of 11) was an unrecognized lack of ven- Anesthesia. Huntington, NY: Robert Kreiger, 1972, Chapter 8. 6  Chapter 1 – The History of Anesthesia and Perioperative Monitoring 6. Duncum B. The Development of Inhalation Anaesthesia. Part 9: 28. Gillespie NA. The signs of anesthesia. Anesth Analg. The beginnings of modern anaesthesia. Chapter 18: The jubilee of 1943;22:275–282. anaesthesia. Geoffrey Cumberlege, London: Oxford University 29. Calmes SA. Arthur Guedel, M.D. and the eye signs of anesthesia. Press. 1947:537–540. ASA Newsletter, September 2002. https://www.asahq.org/ 7. Clover JT. On an Apparatus for Administering Nitrous Oxide Gas Newsletters/2002/9 02/feature5.htm (accessed May 25, 2009). and Ether, Singly or Combined. Br Med J 1876;2(Issue 811):74–75 30. Courington FW, Calverley RK. Anesthesia on the western front: (Published 15 July 1876). the Anglo-American experience of World War I. Anesthesiology 8. Simpson WG, ed. Works of Sir J. J. Simpson. New York: Appleton 1986;65:642–653. & Co., 1872. 31. Poiseuille JLM. 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Volumen nach dem Fickschen Prinzip. Munch Med Wochenschr 26. Zahed B, Sadove MS, Hatano S, Wu HH. Comparison of 1930; 77:1311. automated Doppler ultrasound and Korotkoff measurements of 49. Cournand AF. Measurement of cardiac output in man using the blood pressure of children. Anesth Analg 1971;50:699–704. technique of catheterization of the right auricle. J Clin Invest 27. Silas JH, Barker AT, Ramsey LE. Clinical evaluation of Dinamap 1945;24:105–116. 845 automated blood pressure recorder. Br Heart J 1980;43: 50. Dexter L, Haynes FW, Burwell CS, Eppinger EC, Sagerson RP, 202–205. Evans JM. Studies of congenital heart disease: II. The pressure and 7  Monitoring in Anesthesia and Perioperative Care oxygen content of blood in the right auricle, right ventricle and 60. Katz RL. A nerve stimulator for the continuous monitoring of pulmonary artery in control patients, with observations on the muscle relaxant action. 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Gadgeteering for health care: The John W. and related severe injury through safety monitoring. Severinghaus Lecture on Translational Science. Anesthesiology Anesthesiology 1989;70:572–577. 2009;110:721–728. 64. Cooper JB, Newbower RS, Long CD, McPeek B. Preventable 54. Clark LC Jr, Gollan F, Gupta VB. The oxygenation of blood by gas anesthesia mishaps: a study of human factors. Anesthesiology dispersion. Science 1950;111:85–87. 1978;49:399–406. 55. Severinghaus JW, Bradley AF. Electrodes for blood pO2 and 66. Cooper JB, Newbower RS, Kitz RJ. An analysis of major pCO2 determination. J Appl Physiol 1958;13:515–520. errors and equipment failures in anesthesia management: 56. Severinghaus JW, Peabody JL, Thunstrom A, Eberhard P, considerations for prevention and detection. Anesthesiology Zappia E, eds. Workshop on methodologic aspects of 1984;60:34–42. transcutaneous blood gas analysis. Acta Anaesthesiol Scand 67. Cooper JB. Toward prevention of anesthetic mishaps. 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Anesthesiology 1989;70:572–577. 8  Chapter Medicolegal implications of monitoring 2 Jeffrey M. Feldman Introduction Although the proliferation of technology can increase the If you have never received a letter with the return address of an potential for malpractice liability, Jacobsen recognizes that the unknown law firm, consider yourself lucky. In the case of a mal- specialty of anesthesiology provides one example in which practice proceeding, you will open the letter and typically find technology, and patient monitoring in particular, has actually your name in a long list of defendants. Sometimes the letter is reduced malpractice liability by reducing the risk of serious anticipated, but often, the precipitating events occurred so long injury. For a number of years, anesthesiology ranked at the ago that the details are difficult to recall. top of the medical specialties in malpractice claims and the Whatever the circumstances, a malpractice suit unleashes severity of patient injury. In 1986, the Harvard Medical School a sequence of events with an unpredictable outcome. The trial Department of Anesthesia adopted a minimum standard for venue, the quality of the attorneys, the members of the jury, the patient monitoring during anesthesia.2 This standard included expert witnesses involved, the ability of the plaintiff to engen- provisions for monitoring ventilation, preferably by capnogra- der sympathy, the perceived credibility of the defendant, and phy. Interestingly, pulse oximetry, which had only recently been the quality of the documentation all play a role in the ultimate introduced, was advocated as a means to monitor the circula- outcome. The plaintiff ’s attorney will leave no stone unturned tion, not oxygenation. The primary goal of the Harvard stan- in building the case for malpractice. Because physiologic mon- dard was to improve patient safety by reducing adverse events, itoring is essential to safe patient care, the plaintiff ’s attorney with a secondary goal of reducing malpractice claims. Malprac- is likely to scrutinize how the patient was monitored in build- tice insurance carriers became convinced of the value of these ing the case. The intent of this chapter is to explore the ways in guidelines to mitigate malpractice exposure and, in an effort which physiologic monitoring and exposure to malpractice lia- to catalyze more widespread adoption, offered to reduce pre- bility are related. The intent is not to offer a comprehensive dis- miums to practices that adhered to the monitoring guidelines. cussion of the nuances of malpractice liability. If you are named The result was a significant reduction in the number and sever- in a malpractice suit, there is no better resource than a skilled ity of claims against anesthesiologists.3 A review of 1175 closed defense attorney. malpractice claims filed between 1974 and 1988 underscores In a chapter titled “Medical Liability and the Culture of the potential for physiologic monitoring to reduce malpractice Technology,” Jacobsen argues, “The history of medical liabil- claims. The reviewers determined that one-third of the injuries ity is a struggle between technological advances and injuries could have been prevented by the use of monitoring devices, suffered when those advances fail.”1 He goes on to observe most notably pulse oximetry and capnometry.4 that technical advances empower physicians to tackle ever more Establishing monitoring standards was facilitated by the complex and challenging medical problems with the attendant development of monitoring devices that were easy to use and increased risks. In some cases, the outcome is a return to the cost-effective. The resulting outcome clearly established the previous state of health, but that is not always the case. The pub- relationship between physiologic monitoring and patient safety. lic, on the other hand, demands – and has come to expect – The motivation for these efforts was to reduce the risk of patient perfect outcomes. Although a physician may clearly understand injury. The financial realities of the malpractice system cre- that a less-than-perfect outcome is much better than even more ated the business case, as avoiding even one wrongful death or severe disability or death, the patient perceives only the loss of hypoxic injury suit would pay for multiple patient monitors. his or her health. Physiologic monitoring has facilitated increas- Risk management strategies typically focus on adherence to ingly complex surgical procedures for sicker patients. Even the the standard of care, the importance of documentation, and the most confident clinician would be unlikely to attempt to pro- patient–physician relationship. Monitoring patients appropri- vide anesthesia for liver transplantation using just a finger on ately reduces the risk of significant injury and is therefore an the pulse. The most sophisticated monitoring, however, cannot important part of risk management in anesthesia. As a result of prevent undesired outcomes in sick patients undergoing com- the Harvard experience, the American Society of Anesthesiolo- plex procedures and the resulting exposure to malpractice suits. gists (ASA) established a standard for anesthetic monitoring. 9  Monitoring in Anesthesia and Perioperative Care It is notable that the ASA has chosen to include the word minimal safe practice standard. In some cases, the professional “standard” in the title of this document, which establishes the is held to the standard in his or her geographic practice area content to indicate the standard of care.∗ As we will see, this so, for example, a rural physician in a community hospital is monitoring standard is the most unambiguous evidence that not held to the same standard as a physician with the resources can be presented in court for the standard of care because it of a tertiary-care urban hospital. For individual specialties, the does not require the opinion of an expert witness. Furthermore, standard could be applied to a reasonably prudent professional there is good evidence from the ASA closed-claims database in the same specialty. that when adherence to a standard of care can be demon- Negligent acts can be acts of commission or omission. In strated, there is a reduced chance of payment for a malpractice the former case, the liable party must do something that, under claim.5 To better understand the importance of the standard of similar circumstances, a reasonably prudent professional would care, consider the elements of proof that are required in a mal- have done differently or not at all. An act of omission is the practice proceeding. failure to do something that a reasonably prudent professional would have done under the same circumstances. An act of commission in patient monitoring, for example, would involve Burden of proof using a monitoring device that exposes a patient to injury when Although the outcome of a malpractice suit can sometimes using that device would not be considered standard of care. An seem capricious, the burden of proof that must be satisfied by act of omission in patient monitoring would involve failing to the plaintiff ’s attorney is well defined. Understanding the bur- use a monitoring modality that is considered the minimal safe den of proof is a useful foundation for evaluating the role of any practice. The terminology “reasonably prudent professional” is aspect of care that is used to build a case for malpractice. an attempt to create an objective standard for evaluating a per- In the broad sense, health care malpractice liability arises son’s actions. In the case of an anesthesia provider, the “rea- from five areas of exposure:6 sonably prudent” definition would indicate an individual who r Professional negligence (substandard care delivery) is trained and licensed in accordance with applicable laws and r Intentional misconduct professional standards. r Breach of a therapeutic promise (breach of contract) The failure to follow indicated monitoring standards is not r Patient injury from dangerous treatment-related activities, in itself sufficient proof of negligence. The plaintiff’s attorney regardless of fault (strict liability) has the burden to prove the following four elements:8 r Patient injury from dangerous devices (product liability) r The professional had a duty to care for the patient. Of these areas of exposure, professional negligence is the r The professional breached the duty to care for the patient most common basis for suit against an individual health care by providing substandard care. provider. Most of the discussion in this chapter focuses on the r The injury suffered by the patient was caused by the breach role of physiologic monitoring in establishing a case for negli- of duty. gence against a health care provider. Physiologic monitors can r The damages to the patient are compensable. be involved in a suit related to strict or product liability. In the latter case, the liability suit would typically be directed toward Of these four elements, the second and third can be related to the manufacturer, and debate would ensue about whether it was the manner in which a physiologic monitor is used. Using a the device or failure to use it correctly that caused the injury. device that may cause injury when the device is not indicated, or Negligence is defined as “conduct which falls below the stan- failing to use a device when it is indicated, are examples of sub- dard established by law for the protection of others against standard care absent a compelling explanation by the provider. unreasonable risk of harm.”7 When professional negligence is Other examples would include pulmonary artery rupture from considered, the “standard” by which the care is measured is placing a pulmonary artery catheter that is not indicated, or considered to be the minimally acceptable practice. Practition- hypoxic injury wh