Philadelphia, Pa. — Patients have a significantly lower death rate after surgery when their anesthesia is directed by an anesthesiologist, a physician specialized in anesthesia care. A study of 217,000 Medicare patients in Pennsylvania who underwent general surgery or orthopedic surgery between 1991 and 1994 found an excess death rate of one out of every 400 patients when anesthesiologists did not personally provide or direct the anesthesia care. The lead author of the study, which will be published in the July issue of the peer-reviewed journal Anesthesiology, is Jeffrey H. Silber, M.D., Ph.D., director of the Center for Outcomes Research at The Children’s Hospital of Philadelphia. Dr. Silber presented his findings on June 27 at the annual national meeting of the Association for Health Services Research in Los Angeles.
Collaborating on the study were faculty and staff from The Children’s Hospital of Philadelphia and from the University of Pennsylvania, where Dr. Silber is an associate professor of Pediatrics, Anesthesia, and Health Care Systems.
Dr. Silber’s team studied the post-surgical outcomes of 217,000 elderly patients, based on Medicare billing data from 245 Pennsylvania hospitals. Of the total cases, 194,000 were directed by an anesthesiologist, meaning that specialist physician personally performed anesthesia procedures or was physically present to direct nurse anesthetists or anesthesia residents in administering anesthesia. In the other 23,000 cases, an anesthesiologist or another physician supervised the anesthesia care; supervision is a defined as a lower level of physician participation than medical direction and does not require the anesthesiologist to be physically present in the operative suite.
The researchers found that the mortality rate within 30 days after admission was higher for patients whose care was not directed by an anesthesiologist. They measured 2.5 excess deaths per 1000 patients in this group. Another measurement, called failure-to-rescue, accounts for death rates in patients with complications, and found an effect of 6.9 excess deaths per 1000 cases in which a complication occurred in the undirected group. There was no difference in the overall rate of patients with complications between provider types. "This result suggests that advanced medical training may allow for better management of complications, leading to less serious complications and therefore fewer subsequent deaths," said Dr. Silber. The researchers found that the differences in outcome persisted even after the statistics were adjusted for severity of illness at the time of admission and differences in hospital characteristics.
After adjustments for patient and hospital factors, the study found that the three most significant factors independently associated with better patient survival were: (1) higher nurse-to-bed ratio; (2) large hospital size; and (3) direct involvement of the anesthesiologist. Each factor had a similar impact on mortality reduction.
Dr. Silber added that future, more refined research is needed, to analyze detailed information in medical charts in order to better understand the processes governing outcomes for surgical patients. Nevertheless, he says, "the current study is important for the millions of Medicare patients who undergo general and orthopedic surgery. Whether the results can be generalized to non-Medicare patients and to other surgical procedures remains to be seen."
The Children’s Hospital of Philadelphia, the nation’s first children’s hospital, is a leader in patient care, education and research. This 373-bed multispecialty hospital provides comprehensive pediatric services, including home care, to children from before birth through age 19. The hospital is second in the United States among all children’s hospitals in total research funding from the National Institutes of Health.
Materials provided by The Children's Hospital Of Philadelphia. Note: Content may be edited for style and length.
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