The Effect of Two Different Intraoperative Doses of Dexmedetomidine on Postoperative Cognitive Dysfunction in Elderly Patients Undergoing Major Abdominal Surgery Under General Anesthesia: A Randomized Controlled Study

Background: Postoperative cognitive dysfunction (POCD) is a significant complication among elderly patients undergoing major abdominal surgery. Dexmedetomidine is commonly used as an adjunct to general anaesthesia, but the effect of different intraoperative dosing regimens on early postoperative cognitive outcomes remains unclear. This study evaluated the impact of two different dexmedetomidine doses on early postoperative cognitive outcomes. Methods: A randomized, double-blind, controlled study was conducted on 72 elderly patients (≥60 years) undergoing elective major abdominal surgery under general anaesthesia. Patients were allocated into three groups (n = 24 each): Group P (placebo), Group D1 (dexmedetomidine 1 µg/kg bolus + 0.2 µg/kg/hr infusion), and Group D2 (dexmedetomidine 1.5 µg/kg bolus + 0.5 µg/kg/hr infusion). Cognitive function was assessed using the Montreal Cognitive Assessment (MoCA) scale preoperatively and at one, six, and 24 hours postoperatively. A decline of more than five points was considered significant POCD. Hemodynamic parameters and adverse events were also recorded. Results: Baseline characteristics were comparable across all groups. At one hour postoperatively, MoCA scores were significantly higher in D1 and D2 compared with placebo (p = 0.046). At six hours, cognitive recovery was significantly better in D2, followed by D1, compared with placebo (p < 0.001). The incidence of significant cognitive decline (>5-point fall) was lowest in D1 and D2 (12.5% each) and highest in the placebo group (37.5%, p = 0.048). Dexmedetomidine groups showed more stable intraoperative hemodynamics without significant increases in adverse events. Conclusion: Intraoperative dexmedetomidine significantly attenuates early POCD in elderly patients undergoing major abdominal surgery, with the higher dose demonstrating the greatest cognitive preservation. Dexmedetomidine may be safely incorporated into anaesthetic protocols to improve postoperative neurocognitive outcomes in high-risk elderly surgical patients.