COGNITIVE EFFECTS AFTER EPIDURAL VS GENERAL-ANESTHESIA IN OLDER ADULTS - A RANDOMIZED TRIAL

Objective.-To compare the effect of epidural vs general anesthesia on the incidence of long-term cognitive dysfunction after total knee repl acement surgery in older adults. Design.-Randomized controlled clinica l trial. Setting.-Orthopedic specialty academic hospital. Patients.-A total of 262 patients undergoing elective primary total knee replaceme nt with a median age of 69 years; 70% women. Intervention.-Random assi gnment to either epidural or general anesthesia. Main Outcome Measures .-A thorough neuropsychological assessment was performed preoperativel y and repeated at 1 week and 6 months postoperatively. Cognitive outco me was assessed by within-patient change on 10 tests of memory, psycho motor, and language skills. Prospective standardized surveillance for cardiovascular complications was performed to allow simultaneous asses sment of anesthetic effects on cognitive and cardiovascular outcomes. Results.-The two groups were similar at baseline in terms of age, sex, comorbidity, and cognitive function. There were no significant differ ences between the epidural and general anesthesia groups in within-sub ject change from baseline on any of the 10 cognitive test results at e ither 1 week or 6 months. Overall, 5% of patients showed a long-term c linically significant deterioration in cognitive function. There was n o difference between the anesthesia groups in the incidence of major c ardiovascular complications (3% overall). Conclusions.-The type of ane sthesia, general or epidural, does not affect the magnitude or pattern of postoperative cognitive dysfunction or the incidence of major card iovascular complications in older adults undergoing elective total kne e replacement. This is the largest trial of the effects of general vs regional anesthesia on cerebral function reported to date, with more t han 99% power to detect a clinically significant difference on any of the neuropsychological tests.