Efficacy and safety of dexmedetomidine infusion without induction dose on postoperative delirium in geriatric patients undergoing major noncardiac surgeries: a randomized controlled clinical trial

BACKGROUND: The impact of dexmedetomidine on postoperative delirium (POD) remains a subject of debate in elderly patients undergoing noncardiac surgeries. This study aimed to assess the efficacy and safety of dexmedetomidine infusion without an induction dose in reducing the incidence of POD while maintaining hemodynamic stability in geriatric patients undergoing major surgeries. The loading dose was omitted based on the hypothesis that continuous dexmedetomidine infusion without a loading dose would lower the incidence of POD while preserving cardiovascular safety. METHODS: This randomized, double-blind clinical trial was conducted on 122 elderly patients, belonging to the American Society of Anesthesiologists I or II physical status, who were scheduled for major noncardiac surgeries. Patients were randomly allocated into two equal groups. Patients in Group I received 0.5 μg/kg/h of dexmedetomidine, diluted in 50 mL of isotonic normal saline, while patients in Group II received 50 mL of isotonic normal saline as a placebo. The primary outcome was the incidence of POD. Secondary outcomes included intraoperative and postoperative hemodynamics. RESULTS: Postoperative delirium was observed in only one (1.64%) patient in Group I on the first postoperative day, whereas 21 (34.4%) patients in Group II experienced POD with a statistically significant difference (P<0.001). Furthermore, patients in group I exhibited a significant reduction in intraoperative mean arterial pressure and heart rate, along with a notably high incidence of intraoperative hypotension but without bradycardia. Postoperatively, the mean heart rates, the incidence of hypotension, and bradycardia were comparable between groups without the need for rescue hypotensive medications (all P>0.05). CONCLUSIONS: In elderly patients undergoing non-cardiac surgery, dexmedetomidine infusion without an induction dose effectively and safely reduces the incidence of POD. Dexmedetomidine significantly preserves postoperative hemodynamics.