Introduction: Postoperative delirium is a frequent complication associated with prolonged recovery, increased morbidity, and higher healthcare costs. Dexmedetomidine may reduce delirium through its sedative, analgesic-sparing, and sympatholytic effects, although evidence remains inconsistent. This randomized controlled trial aimed to evaluate the effect of intraoperative dexmedetomidine administration on postoperative delirium scores during the first 72 hours.

Material and methods: In this double-blind, randomized controlled trial conducted at Imam Reza Hospital, 50 surgical patients were allocated (1:1) to receive either intraoperative dexmedetomidine (0.5 µg/kg bolus, then 0.2–0.5 µg/kg/h infusion) or 0.9% normal saline. Postoperative delirium was evaluated during the first 72 hours using the Confusion Assessment Method (CAM/CAM-S).

Results: Across the first 72 postoperative hours, the dexmedetomidine group showed consistently lower delirium severity and incidence than controls, with the greatest separation at 24–48 hours; delirium scores peaked early and then declined in both groups, but remained lower with dexmedetomidine at every assessment (all time points: P<0.05). In parallel, the dexmedetomidine group had lower intraoperative heart rate and slightly lower mean arterial pressure, along with significantly lower postoperative VAS pain scores from 1 to 24 hours (all comparisons: P<0.05).

Conclusion: Intraoperative dexmedetomidine appears to reduce early postoperative delirium burden while improving analgesia and maintaining acceptable hemodynamic stability. These findings support its role as a useful perioperative adjunct, likely through attenuation of surgical stress, sympathetic activation, and pain-related neurocognitive disruption.