Comparing the prophylactic effect of ondansetron versus ephedrine on hemodynamic instability caused by spinal anesthesia for cesarean section.

BACKGROUND AND AIMS: This study aimed to compare the prophylactic effect of intravenous ondansetron versus ephedrine on hypotension related to spinal anesthesia of cesarean section. The primary outcome was the incidence of maternal hypotension; secondary outcomes were the incidence of nausea and vomiting, the number of vasopressors required, and surgeon satisfaction.

MATERIAL AND

METHODS

This randomized, double-blind clinical trial study included 120 parturients with ASA physical status I or II who were eligible for elective cesarean section. They were randomly assigned to two groups: receiving ephedrine (10 mg in 10 mL normal saline 0.9% IV) and ondansetron (8 mg in 10 mL normal saline 0.9% IV). The patients were monitored for changes in hemodynamic parameters during surgery and recovery.

RESULTS

Among 120 parturients included in this clinical trial, the incidence of hypotension (20% decrease in systolic blood pressure) was significantly lower in the ephedrine group (21.7%) than in the ondansetron group (60%) (P < 0.001). In addition, the incidence of fall of mean arterial pressure to below 60 mmHg was significantly lower in the ephedrine group (3.3%) than in the ondansetron group (18.3%) (P = 0.016) during surgery. Prophylactic administration of ephedrine also significantly decreased the need for rescue vasopressor compared to ondansetron group (P < 0.001). No difference was observed in the rate of complications and surgeon satisfaction among groups (P = 0.228 and 0.36, respectively).

CONCLUSIONS

We found that 10 mg IV ephedrine has a significantly greater prophylactic effect than 8 mg IV ondansetron on spinal-induced hypotension during elective cesarean section.