Charles P. Gibbs

Anesthesia-related Deaths during Obstetric Delivery in the United States, 1979–1990

Background Anesthesia‐related complications are the sixth leading cause of pregnancy‐related death in the United States. This study reports characteristics of anesthesia‐related deaths during obstetric delivery in the United States from 1979–1990. Methods Each state reports deaths that occur within 1 yr of delivery to the Centers for Disease Control and Prevention as part of the ongoing Pregnancy Mortality Surveillance. Maternal death certificates (with identifiers removed) matched with live birth or fetal death certificates when available from 1979–1990 were reviewed to identify deaths due to anesthesia, the cause of death, the procedure for delivery, and the type of anesthesia provided. Maternal mortality rates per million live births were calculated. Case fatality rates and risk ratios were computed to compare general to regional anesthesia for cesarean section deliveries. Results The anesthesia‐related maternal mortality rate decreased from 4.3 per million live births in the first triennium (1979–1981) to 1.7 per million in the last (1988–1990). The number of deaths involving general anesthesia have remained stable, but the number of regional anesthesia‐related deaths have decreased since 1984. The case‐fatality risk ratio for general anesthesia was 2.3 (95% confidence interval [CI], 1.9–2.9) times that for regional anesthesia before 1985, increasing to 16.7 (95% CI, 12.9–21.8) times that after 1985. Coclusions Most maternal deaths due to complications of anesthesia occurred during general anesthesia for cesarean section. Regional anesthesia is not without risk, primarily because of the toxicity of local anesthetics and excessively high regional blocks. The incidence of these deaths is decreasing, however, and deaths due to general anesthesia remain stable in number and hence account for an increased proportion of total deaths. Heightened awareness of the toxicity of local anesthetics and related improvements in technique may have contributed to a reduction in complications of regional anesthesia.

Obstetric anesthesia work force survey, 1981 versus 1992.

Background: In 1981, with support from the American Society of Anesthesiologists and the American College of Obstetricians and Gynecologists, anesthesia and obstetric providers were surveyed to identify the personnel and methods used to provide obstetric anesthesia in the United States. The survey was expanded and repeated in 1992 with support from the same organizations. Methods: Comments and questions from the American Society of Anesthesiologists Committee on Obstetrical Anesthesia and the American College of Obstetricians and Gynecologists Committee on Obstetric Practice were added to the original survey instrument to include newer issues while allowing comparison with data from 1981. Using the American Hospital Association registry of hospitals, hospitals were differentiated by number of births per year (stratum I, >or= to 1,500 births; stratum II, 500–1,499 births; stratum III, < 500 births) and by U.S. census region. A stratified random sample of hospitals was selected. Two copies of the survey were sent to the administrator of each hospital, one for the chief of obstetrics and one for the chief of anesthesiology. Results: Compared with 1981 data, there was an overall reduction in the number of hospitals providing obstetric care (from 4,163 to 3,545), with the decrease occurring in the smallest units (56% of stratum III hospitals in 1981 compared with 45% in 1992). More women received some type of labor analgesia, and there was a 100% increase in the use of epidural analgesia. However, regional analgesia was unavailable in 20% of the smallest hospitals. Spinal analgesia for labor was used in 4% of parturients. In 1981, obstetricians provided 30% of epidural analgesia for labor; they provided only 2% in 1992. Regional anesthesia was used for 78–85% (depending on strata) of patients undergoing cesarean section, resulting in a marked decrease in the use of general anesthesia. Anesthesia for cesarean section was provided by nurse anesthetists without the medical direction of an anesthesiologist in only 4% of stratum I hospitals but in 59% of stratum III hospitals. Anesthesia personnel provided neonatal resuscitation in 10% of cesarean deliveries compared with 23% in 1981. Conclusions: Compared with 1981, analgesia is more often used by parturients during labor, and general anesthesia is used less often in patients having cesarean section deliveries. In the smallest hospitals, regional analgesia for labor is still unavailable to many parturients, and more than one half of anesthetics for cesarean section are provided by nurse anesthetists without medical direction by an anesthesiologist. Obstetricians are less likely to personally provide epidural analgesia for their patients. Anesthesia personnel are less involved in newborn resuscitation.

Anesthesia-Related Maternal Mortality in the United States : 1979-2002

OBJECTIVE: To examine 12 years of anesthesia-related maternal deaths from 1991 to 2002 and compare them with data from 1979 to 1990, to estimate trends in anesthesia-related maternal mortality over time, and to compare the risks of general and regional anesthesia during cesarean delivery. METHODS: The authors reviewed anesthesia-related maternal deaths that occurred from 1991 to 2002. Type of anesthesia involved, mode of delivery, and cause of death were determined. Pregnancy-related mortality ratios, defined as pregnancy-related deaths due to anesthesia per million live births were calculated. Case fatality rates were estimated by applying a national estimate of the proportion of regional and general anesthetics to the national cesarean delivery rate. RESULTS: Eighty-six pregnancy-related deaths were associated with complications of anesthesia, or 1.6% of total pregnancy-related deaths. Pregnancy-related mortality ratios for deaths related to anesthesia is 1.2 per million live births for 1991–2002, a decrease of 59% from 1979–1990. Deaths mostly occurred among younger women, but the percentage of deaths among women aged 35–39 years increased substantially. Delivery method could not be determined in 14%, but the remaining 86% were undergoing cesarean delivery. Case-fatality rates for general anesthesia were 16.8 per million in 1991–1996 and 6.5 per million in 1997–2002, and for regional anesthesia were 2.5 and 3.8 per million, respectively. The resulting risk ratio between the two techniques for 1997–2002 was 1.7 (confidence interval 0.6–4.6, P=.2). CONCLUSION: Anesthetic-related maternal mortality decreased nearly 60% when data from 1979–1990 were compared with data from 1991–2002. Although case-fatality rates for general anesthesia are falling, rates for regional anesthesia are rising. LEVEL OF EVIDENCE: II

Oral intake policies on labor and delivery: a national survey

STUDY OBJECTIVE To examine current policies on oral intake during labor among hospitals throughout the United States. DESIGN AND SETTING Anonymous questionnaire survey distributed to the directors of anesthesia and obstetrics departments of 740 hospitals. Completed surveys were then grouped by number of deliveries performed each year. MEASUREMENTS AND MAIN RESULTS A total of 2,265 surveys were distributed. Of that number, 902 (33% response rate) surveys, representing 740 U.S. hospitals, were returned. Of the surveys returned, 419 surveys were received from obstetricians and 401 surveys were received from anesthesiologists. Oral intake during labor is limited primarily to clear liquids, although hospitals with fewer deliveries allow significantly more oral intake during latent phase than do hospitals with larger services. Allowing nonclear liquids or solid foods is uncommon in either phase of labor, regardless of hospital size. CONCLUSIONS The results give an indication of oral intake policies used by labor and delivery units in the United States, and they may be helpful for obstetric services that are in the process of developing their own policies.

Practice Guidelines for Preoperative Fasting and the Use of Pharmacologic Agents to Reduce the Risk of Pulmonary Aspiration: Application to Healthy Patients Undergoing Elective Procedures

P RACTICE Guidelines are systematically developed recommendations that assist the practitioner and patient in making decisions about health care. These recommendations may be adopted, modified, or rejected according to clinical needs and constraints and are not intended to replace local institutional policies. In addition, Practice Guidelines developed by the American Society of Anesthesiologists (ASA) are not intended as standards or absolute requirements, and their use cannot guarantee any specific outcome. Practice Guidelines are subject to revision as warranted by the evolution of medical knowledge, technology, and practice. They provide basic recommendations that are supported by a synthesis and analysis of the current literature, expert and practitioner opinion, open forum commentary, and clinical feasibility data. This update includes data published since the Practice Guidelines for Preoperative Fasting and the Use of Pharmacologic Agents to Reduce the Risk of Pulmonary Aspiration were adopted by the ASA in 1998 and published in 1999.*

Anesthesia-Related Maternal Mortality in the United States: 1979–2002

The death rate from the complications of pregnancy has decreased by 99% since 1900, but no further decreases have been reported in the past 20 years. Among women who die after a live birth, the leading causes of death are embolism and hypertensive disorders of pregnancy. Anesthetic causes of maternal mortality have declined even more than obstetric causes and now account for <2% of pregnancy-related maternal mortality in the United States. This study examined 12 years of anesthesia-related maternal deaths from 1991 to 2002 and compared them with data from 1979 to 1990 in an effort to find trends in anesthesiarelated maternal mortality over time and to compare the risks of general and regional anesthesia during cesarean delivery. The Pregnancy Mortality Surveillance System of the Centers for Disease Control and Prevention maintains a database of all reported deaths that are causally related to pregnancy. A woman’s death is classified as pregnancy-related if it occurred during pregnancy or within 1 year of pregnancy and resulted from complications of the pregnancy, a chain of events initiated by the pregnancy, or an aggravation of an unrelated condition by the physiologic effects of pregnancy or its management. Of the 5946 pregnancy-related deaths in the database for 1991 to 2002, 86 were determined to be caused by anesthesia-related complications which 3 obstetric anesthesiologists independently confirmed. The type of anesthesia involved, mode of delivery, and cause of death were extrapolated from the database. Pregnancy-related mortality ratios, defined as pregnancy-related deaths due to anesthesia per million live births were calculated. Case-fatality rates were determined by dividing number of deaths due to regional and general anesthetics by the estimated number of instances of that type of anesthesia during cesarean delivery in the same period. To compare the data from the United States with that from the United Kingdom, pregnancy mortality rates were calculated by triennium. The 86 pregnancy-related deaths associated with complications of anesthesia accounted for 1.6% of the total pregnancy-related deaths in the United States. The overall pregnancy-related mortality ratios for deaths related to anesthesia complications were 1.2 and 2.9 per million live births for 1991 to 2002 and 1979 to 1990, a decrease of 59%. Of the 86 deaths, 27 early losses were excluded (24 abortion and 3 ectopic deaths) and 3 deaths were excluded because of unknown pregnancy outcome. The 56 remaining cases resulted in a live birth or stillbirth. Pregnancy-related deaths connected with anesthesia mostly occurred among younger women, aged 20 to 24 years, 27% for 1991 to 2002, and 43% for 1979 to 1990. However, deaths among women aged 45 to 49 years increased from 5% for 1979 to 1990 to 18% for 1991 to 2002. The delivery method was determined in 86% of women who died during 1991 to 2002 and of these 86% underwent a cesarean delivery. No known death was associated with a vaginal delivery for 1991 to 2002. The estimated case fatality rate of general anesthesia during cesarean delivery decreased from 16.8 deaths per million general anesthetics to 6.5 deaths per million general anesthetics between 1991 to 1996 and 1997 to 2002. The estimated case fatality rate of regional anesthesia during cesarean delivery increased from 2.5 to 3.8 deaths per million. The leading causes of anesthesia-related pregnancy deaths for 1991 to 2002 were intubation failure or induction problems (23%), respiratory failure (20%), and high spinal or epidural block (16%). For women whose deaths were associated with regional anesthesia during cesarean delivery, 26% were caused by high spinal or epidural block, 19% by respiratory failure, and 19% were due to drug reaction. The present Pregnancy Mortality Surveillance System is the most comprehensive national database available for the analysis of maternal death in the United States, but maternal mortality data are difficult to collect, particularly for individual cases with a bad outcome or “near miss.” Reporting of deaths and the sequence of events, including provision of anesthesia records, should be mandatory if concerns about liability can be overcome. Anesthetic-related mortality from 1991 to 2002 declined greatly when compared with data from 1979 to 2000. Although death rates from general anesthesia are falling, fatality rates from regional anesthesia are rising.