Combined general and neuraxial anesthesia versus general anesthesia: a population-based cohort study

To determine whether combining spinal or epidural anesthesia with general anesthesia (combined anesthesia) reduces major medical complications of elective surgery compared with general anesthesia alone. We conducted a propensity-matched population-based historical cohort study using large healthcare databases from Ontario, Canada. We identified patients undergoing 21 different elective procedures that were amenable to either combined anesthesia or general anesthesia alone in 108 hospitals from 2004 to 2011. We assessed the following four outcomes together as a composite and individually in the 30 days following surgery: acute kidney injury, stroke, myocardial infarction, and all-cause mortality. Prior to matching, we identified 21,701 patients receiving general anesthesia and 8,042 patients receiving combined anesthesia. After matching, our cohort included 12,379 patients. Twenty-eight baseline characteristics were well-matched between the combined (n = 4,773) and general anesthesia groups (n = 7,606). Mean patient age was 66 yr. Relative to general anesthesia alone, combined anesthesia was not associated with a reduced risk for the composite outcome [104/4,773 (2.2%) vs 162/7,606 (2.1%); odds ratio (OR) 0.97; 95% confidence interval (CI) 0.75 to 1.24] or for any of the four component outcomes when examined separately: acute kidney injury (OR 0.93; 95% CI 0.58 to 1.51), stroke (OR 0.79; 95% CI 0.36 to 1.73), myocardial infarction (OR 1.04; 95% CI 0.69 to 1.57), and all-cause mortality (OR 0.91; 95% CI 0.59 to 1.42). The addition of spinal or epidural anesthesia to general anesthesia was not associated with a reduced risk of major medical complications among 21 different elective procedures when compared with general anesthesia alone.