Ketamine as a Neuroprotective Intervention to Prevent Early Post-CABG Delirium: A Triple-Blind Randomized Clinical Trial

Abstract

Background: Postoperative delirium frequently occurs after coronary artery bypass graft (CABG) surgery, negatively impacting patient recovery and outcomes. Ketamine, an N-methyl-D-aspartate (NMDA) receptor antagonist with analgesic and anti-inflammatory effects, is considered a potential strategy for delirium prevention. Objectives: This study examines the efficacy of intravenous ketamine administered during anesthesia induction in reducing postoperativee delirium among CABG patients. Methods: A triple-blind, randomized, placebo-controlled clinical trial was performed on 92 patients scheduled for elective CABG surgery. Participants were randomly allocated to receive either ketamine (0.5 mg/kg, n = 46) or an equivalent placebo dose at anesthesia induction (n = 46). Delirium was assessed at 24 and 48 hours postoperatively using the Intensive Care Delirium Screening Checklist (ICDSC), covering the peak period of delirium incidence after CABG. Due to clinical workflow and resource constraints, long-term follow-up beyond 48 hours was not conducted. Statistical analyses included chi-square tests and t-tests, conducted using SPSS version 19, with a two-sided significance level of 0.05. Results: Baseline demographic and surgical characteristics were similar between groups. Delirium incidence at 24 hours was significantly lower in the ketamine group (2.2%) compared to the control group (17.4%) (P = 0.045). At 48 hours, the rates were 4.4% in the ketamine group versus 26.1% in controls (P = 0.038). These preliminary findings suggest a possible association between ketamine and reduced early delirium, though small event numbers and short follow-up limit definitive conclusions. Conclusions: Ketamine was associated with a lower incidence of early postoperative delirium; however, the small number of delirium events limits the strength of this conclusion. Larger trials with extended follow-up and comprehensive safety monitoring are essential before clinical implementation.