Anesthesiology 2007; 106:1096–104 Copyright © 2007, the American Society of Anesthesiologists, Inc. Lippincott Williams & Wilkins, Inc. A Series of Anesthesia-related Maternal Deaths in Michigan, 1985–2003 Jill M. Mhyre, M.D.,* Monica N. Riesner, M.D.,* Linda S. Polley, M.D.,† Norah N. Naughton, M.D., M.B.A.‡ Background: Maternal Mortality Surveillance has been con- ANESTHETIC complication is the seventh leading cause ducted by the State of Michigan since 1950, and anesthesia- of pregnancy-related mortality in the United States, ac- related maternal deaths were most recently reviewed for the counting for 1.6% of all pregnancy-related deaths.1 Al- years 1972–1984. Methods: Records for pregnancy-associated deaths between though rare, anesthesia-related maternal mortality is po- 1985 and 2003 were reviewed to identify 25 cases associated tentially preventable. with a perioperative arrest or major anesthetic complication. The causes of anesthetic induced mortality have Downloaded from http://pubs.asahq.org/anesthesiology/article-pdf/106/6/1096/364376/0000542-200706000-00008.pdf by guest on 01 October 2021 Four obstetric anesthesiologists independently classified these evolved over time. For example, obstetric deaths associ- cases, and disagreements were resolved by discussion. Precise ated with regional anesthesia declined in the mid-1980s.2 definitions of anesthesia-related and anesthesia-contributing The decline was attributed the withdrawal of 0.75% maternal death were constructed. Anesthesia-related deaths bupivacaine, increased awareness of local anesthetic were reviewed to identify the chain of medical errors or care management problems that contributed to each patient death. toxicity, and the use of test dosing for epidural catheters. Results: Of 855 pregnancy-associated deaths, 8 were anesthe- In recent reviews, failed intubation during general anes- sia-related and 7 were anesthesia-contributing. There were no thesia remains an important cause of anesthesia-related deaths during induction of general anesthesia. Five resulted maternal death.3–5 In response, anesthetic practice has from hypoventilation or airway obstruction during emergence, shifted to rely more heavily on regional anesthesia for extubation, or recovery. Lapses in either postoperative moni- cesarean delivery6,7 and thereby minimize the need for toring or anesthesiology supervision seemed to contribute to 5 invasive airway management in obstetrics. Concomitant of the 8 anesthesia-related deaths. Other characteristics com- -and African-Amer- clinical and educational efforts have focused on strate (6 ؍ mon to these cases included obesity (n 8,9 .gies to manage the difficult airway .(6 ؍ ican race (n Conclusions: The 8 anesthesia-related and seven anesthesia- Maternal Mortality Surveillance has been conducted by contributing maternal deaths in Michigan between 1985 and the State of Michigan since 1950, and anesthesia-related 2003 illustrate three key points. First, all anesthesia-related maternal deaths were most recently reviewed for the deaths from airway obstruction or hypoventilation took place years 1972–1984.10 In this retrospective study, case files during emergence and recovery, not during the induction of of all pregnancy-associated deaths recorded in the State general anesthesia. Second, system errors played a role in the majority of cases. Of concern, lapses in postoperative monitor- of Michigan between 1985 and 2003 were reviewed to ing and inadequate supervision by an anesthesiologist seemed determine whether the recent focus on airway manage- to contribute to more than half of the deaths. Finally, this report ment in obstetric anesthesiology has influenced the confirms previous work that obesity and African-American race causes of anesthesia-related maternal death for women are important risk factors for anesthesia-related maternal mor- in Michigan. tality. This article is accompanied by an Editorial View. Please see: Materials and Methods ᭜ D’Angelo R: Anesthesia-related maternal mortality: A pat on the back or a call to arms? ANESTHESIOLOGY 2007; 106:1082–4. This protocol was approved by the University of Mich- igan Health System Privacy Board and the Michigan De- partment of Community Health. Maternal death report- * Lecturer in Anesthesiology, † Associate Professor of Anesthesiology, ‡ Asso- ing is not mandatory in Michigan. Since its inception in ciate Professor of Anesthesiology and Associate Professor of Obstetrics and 11 Gynecology. 1950, Michigan Maternal Mortality Surveillance Received from the Department of Anesthesiology, Division of Obstetric Anes- (MMMS) relied on voluntary reports by hospitals, medi- thesiology, University of Michigan Health System, Ann Arbor, Michigan. Submit- cal examiners, other health and social service providers, ted for publication August 10, 2006. Accepted for publication February 5, 2007. 10–15 Supported by the University of Michigan Department of Anesthesiology, Ann and newspaper obituaries. Beginning in 1990, the Arbor, Michigan; the Robert Wood Johnson Clinical Scholars Program, Palo Alto, Michigan Department of Community Health has California; and the Building Interdisciplinary Research Careers in Women’s Health Program sponsored by the National Institutes of Health, Bethesda, Mary- matched death certificates for women of reproductive land. Presented at the Society of Obstetric Anesthesia and Perinatology, Holly- age (10–45 yr old) with live birth certificates for that wood, Florida, April 28, 2006. year and the previous year.13,15,16 Starting in 1999, the Address correspondence to Dr. Mhyre: University of Michigan Health System, Department of Anesthesiology, 1H247 UH Box 0048, 1500 East Medical Center Michigan Department of Community Health electroni- Drive, Ann Arbor, Michigan 48109-0048. [email protected]. Individual article cally linked women’s death certificates with live birth reprints may be purchased through the Journal Web site, www.anesthesiology- 13,16 .org. certificates and fetal death files. § § Division of Reproductive Health: Activities: Maternal and Child Health A pregnancy-associated death is defined as the death of Epidemiology Program; Participating State: Michigan. Center for Disease Control and Prevention. Available at: http://www.cdc.gov/reproductivehealth/MCHEpi/ a woman while pregnant or within 1 yr of the termina- 17 Michigan.htm. Accessed August 8, 2006. tion of pregnancy, irrespective of cause. A pregnancy- Anesthesiology, V 106, No 6, Jun 2007 1096 ANESTHESIA-RELATED MATERNAL DEATHS IN MICHIGAN 1097 Table 1. Number of Postpartum Days during Which a Death weight, cause and timing of death relative to the termi- Was Considered Pregnancy-associated and Included in Case nation of pregnancy, contributing causes leading to Ascertainment Procedures by the State of Michigan death, autopsy findings, and conclusions of the MMMS Years Postpartum Days Medical Review Committee. An abbreviated narrative of the course of events included the surgical or obstetric 1985–1986 42 1987–1989 90 procedure, urgency of the procedure, anesthetic man- 1990–1991 180 agement techniques, airway management techniques, 1992–2003 365 and complications of anesthesia. Four obstetric anesthesiologists independently re- related death is defined as the death of a woman while viewed and classified the 25 cases as anesthesia-related, anesthesia-contributing, or not related to anesthesia. pregnant or within 1 yr of termination of pregnancy Downloaded from http://pubs.asahq.org/anesthesiology/article-pdf/106/6/1096/364376/0000542-200706000-00008.pdf by guest on 01 October 2021 from any cause related to or aggravated by her preg- Cases were initially categorized with reference to defi- 10 nancy or its management, but not from accidental or nitions published by Endler et al. in a previous review incidental causes.17 The relevant postpartum interval of anesthesia-related maternal death in Michigan. Ac- used by the State of Michigan to define a pregnancy- cording to these definitions, “Primary cause was defined associated death increased over the course of the study as a death attributable to anesthesia, either as the result as illustrated in table 1. Once a pregnancy-associated of the medications used, method chosen, or the techni- death is identified, the MMMS coordinator requests avail- cal maneuvers performed, whether iatrogenic in origin able hospital records, autopsy reports, death certificates, or resulting from an abnormal patient response. A con- and, when applicable, birth certificates. For deaths not tributory factor was defined as death to which anesthesia attributed to cancer or injury, a senior obstetrician re- contributed, but one that would likely have occurred 10 views all material and generates a standardized summary. even in the absence of an anesthetic intervention.” These summaries are presented to the MMMS Medical Disagreements among the four reviewers were resolved Review Committee members, who categorize each through an iterative process in which the reviewers se- death as to cause, preventability, and responsible factors quentially refined the definitions of anesthesia-related and (patient, physician, hospital, or community) and deter- anesthesia-contributing maternal mortality and applied mine whether the death was pregnancy-associated or these definitions to the 25 cases as well as to examples in 2,3,10,18,19 pregnancy-related.13 The primary records, case summa- the literature. Discussion continued until all cases ries, and committee data sheets comprise the case files. could be categorized with unanimous agreement.