Comparison of two bolus doses of dexmedetomidine for prophylaxis against postoperative nausea and vomiting in highly susceptible patients: A randomized controlled trial

Abstract Background: Postoperative nausea and vomiting (PONV) prolong hospital stay and decrease the patient’s satisfaction. Our objective was to compare the antiemetic effect of two different concentrations of two bolus doses of Dexmedetomidine (Dex) in PONV high-risk patients. Materials and Methods: This randomized, double-blinded trial was conducted on 180 patients undergoing total thyroidectomy. Participants were randomly divided equally into three groups. At the end of the surgery, group C received 10 mL of normal saline; group D50 received a single bolus dose of 0.5 µ/kg Dex diluted in 10 mL of normal saline, and group D75 received a single bolus dose of 0.75 µ/kg Dex diluted in 10 mL of normal saline. Results: PONV and postoperative morphine consumption were significantly reduced in group D75 compared to group D50 and in both Dex groups compared to group C. The time to give the first rescue antiemetic was significantly higher in group D75 compared to group D50 and in group D50 and group D75 compared to group C. The number of attacks and postoperative consumption of Ondansetron was significantly lower in group D50 and group D75 compared to group C. Patients’ satisfaction was significantly better in both group D50 and group D75 compared to group C (P < 0.001) and in group D75 compared to group D50 (P = 0.02). Conclusion: A bolus dose of Dex having a concentration of 0.75 µ/kg decreased the incidence of PONV in high-risk patients, with subsequent reduction in postoperative opioid consumption and improvement of patients’ satisfaction.