Ketamine attenuates delirium after cardiac surgery with cardiopulmonary bypass

Abstract

Objective: To determine if ketamine attenuates postoperative delirium concomitant with an anti-inflammatory effect in patients undergoing cardiac surgery using cardiopulmonary bypass.

Design: A prospective randomized study.

Setting: A Veterans Affairs medical center.

Participants: Cardiac surgical patients.

Interventions: Patients at least 55 years of age randomly received placebo (0.9% saline, n = 29) or an intravenous bolus of ketamine (0.5 mg/kg intravenously, n = 29) during anesthetic induction in the presence of fentanyl and etomidate.

Measurements and main results: Delirium was assessed by using the Intensive Care Delirium Screening Checklist before and after surgery. Serum C-reactive protein concentrations were determined before and 1 day after surgery. The incidence of postoperative delirium was lower (p = 0.01, Fisher exact test) in patients receiving ketamine (3%) compared with placebo (31%). Postoperative C-reactive protein concentration was also lower (p < 0.05) in the ketamine-treated patients compared with the placebo-treated patients. The odds of developing postoperative delirium were greater for patients receiving placebo compared with ketamine treatment (odds ratio = 12.6; 95% confidence interval, 1.5-107.5; logistic regression).

Conclusions: After cardiac surgery using cardiopulmonary bypass, ketamine attenuates postoperative delirium concomitant with an anti-inflammatory effect.