Effect of epidural dexmedetomidine on post-operative nausea & vomiting in adult patients undergoing abdominopelvic surgery: a randomized controlled study.

Abstract

Background: The incidence of postoperative nausea and vomiting (PONV) has been reported to reach as high as 33.5% in patients undergoing abdominal surgeries. Intravenous dexmedetomidine has been shown to be effective in reducing the incidence of PONV, possibly through the inhibition of catecholamine release and decreased opioid requirements. This study aims to investigate the potential efficacy of epidural dexmedetomidine in preventing PONV in patients undergoing abdominal and pelvic surgery under combined general-epidural anesthesia.

Methods: The study enrolled patients aged 18-65 years with an ASA physical status I-III who were scheduled for elective open abdominal or pelvic surgery. Patients were randomized to receive either a single bolus dose of dexmedetomidine during peritoneal closure or placebo. No additional PONV prophylaxis was provided. Patients in the dexmedetomidine group received 2 mg of morphine combined with dexmedetomidine 1 mcg kg^-1 via the epidural catheter, whereas those in the placebo group received only morphine diluted to an equivalent volume.

Results: Of the 108 patients randomized between August 2024 to April 2025, 99 were included in the final analysis. The incidence of PONV within 1 and 6 h postoperatively was significantly lower in the dexmedetomidine group compared to placebo (3.8% vs. 30.4%; RR 0.12, 95% CI 0.03-0.52, p < 0.001 and 13.2% vs. 32.6%, RR 0.41, 95% CI 0.18-0.91, p = 0.021), respectively. The severity of postoperative nausea was not different between the groups (p = 0.557). The incidence of postoperative shivering was significantly lower in the dexmedetomidine group (0% vs. 15.2%, p = 0.003).

Conclusions: A single administration of epidural dexmedetomidine at 1 mcg kg^-1 significantly reduced both the incidence of early PONV at 1 and 6 h postoperatively and postoperative shivering without increasing hemodynamic complications.

Clinical trial registration: Retrospectively registered with Thai Clinical Trials Registry (TCTR20250331001) on 31 March 2025.