Surgical mortality and type of anesthesia provider.

Although estimates of anesthesia-related deaths today are as low as 1 in 200,000 to 300,000 cases, questions remain about surgical patients' safety related to types of anesthesia providers. We studied the effect of type of anesthesia provider on mortality rates of Medicare patients undergoing 8 different surgical procedures. Risk-adjusted mortality rates were analyzed for 404,194 inpatients undergoing surgery and having complete, unambiguous Medicare bills for anesthesia. Mortality was compared for anesthesiologists working alone, Certified Registered Nurse Anesthetists (CRNAs) working alone, and anesthesia care teams. Procedure-specific risk-adjustment models were derived using stepwise logistic regression. Predictions were adjusted for institutional and geographic factors. Mortality rates for conditions studied ranged from 0.11% to 1.20%. Observed and predicted values by type of provider were not statistically significantly different. Hospitals without anesthesiologists had results similar to hospitals where anesthesiologists provided or directed anesthesia care.