Randomized controlled trial comparing ondansetron and placebo for the reduction of spinal anesthesia-induced hypotension during elective cesarean delivery in Egypt

Objective: To evaluate the effect of prophylactic ondansetron on spinal anesthesia-induced hypotension and bradycardia among patients undergoing elective cesarean deliveries. Methods: A prospective, double-blind, randomized, placebo-controlled trial enrolled patients aged 20-40 years scheduled for elective cesarean delivery under spinal anesthesia between January 1, 2015 and January 31, 2016 at Menoufia University Hospital, Egypt. Patients were randomized to receive intravenous ondansetron 4 mg in 10 mL of saline or 10 mL of saline. Participants and investigators were masked to group assignments. The primary outcomes were systolic and diastolic blood pressure, mean arterial pressure, and heart rate, measured at baseline, 10-minute intervals to 60 minutes, and at 2 hours. Per-protocol analyses were performed including patients who delivered under spinal anesthesia. Results: The analyses included 50 patients in each group. Decreases in systolic blood pressure were reduced among patients receiving ondansetron at all time points (P < 0.05) and diastolic blood pressure did not differ between the groups (P > 0.05). Among patients who received ondansetron, mean arterial pressure was higher immediately and 30 minutes after spinal anesthesia (P < 0.05), higher heart rates were recorded immediately, 20 minutes, and 50 minutes after anesthesia (P < 0.05), and the incidence of nausea (P = 0.020) and vomiting (P = 0.031) were lower. Conclusion: Prophylactic intravenous ondansetron significantly reduced hypotension and heart-rate fluctuations among patients undergoing elective cesarean deliveries under spinal anesthesia. Pan African Clinical Trials Registry: PACTR 201601001397193 (C) 2016 International Federation of Gynecology and Obstetrics. Published by Elsevier Ireland Ltd. All rights reserved.