Effect of fentanyl on nausea and vomiting in cesarean section under spinal anesthesia: a randomized controlled study

Objective Although opioids may induce nausea and vomiting, they possess sedative effects and can reduce intraoperative nausea and vomiting (IONV). This study assessed the effect of adding fentanyl to midazolam on sedation levels and IONV during cesarean section under spinal anesthesia. Methods Eighty parturients scheduled for elective cesarean section were enrolled in the study. Following fetal delivery, patients were administered 0.05 mg/kg of midazolam plus 0.03 mL/kg of normal saline (M group) or 0.05 mg/kg of midazolam plus 1.5 μg/kg of fentanyl (MF group). The primary outcome was the incidence of IONV. The secondary outcomes were incidence of postoperative nausea and vomiting (PONV), intraoperative sedation level, and five-point patient satisfaction score (PSS). Results The IONV incidence was significantly lower in the MF group compared with the M group (5% [2/40] vs. 25% [10/40]). The PONV incidence did not differ significantly between the groups. The intraoperative sedation level tended to be deeper in the MF group. The 5-point PSS was significantly higher in the MF group. There was a strong correlation between the sedation level and IONV incidence. Conclusions Adding fentanyl to midazolam is effective for sedation and to prevent IONV in women who are undergoing cesarean section under spinal anesthesia.