Comparison of remimazolam and midazolam for preventing intraoperative nausea and vomiting during cesarean section under spinal anesthesia: a randomized controlled trial.

Background: Preventing intraoperative nausea and vomiting (IONV) is crucial for maternal safety during cesarean section under spinal anesthesia. While midazolam is known to prevent IONV, we hypothesized that remimazolam would be superior due to its minimal hemodynamic effects. We compared the effects of the two drugs on IONV.

Methods: Parturients scheduled for cesarean section were randomly assigned to receive either midazolam or remimazolam. They received midazolam 2 mg or remimazolam 5 mg, with additional doses administered upon request. The primary outcome measure was the incidence of newly developed IONV during sedation. Other outcomes included overall IONV, rescue antiemetic use, shivering, hemodynamic variables, sedation scale scores, and satisfaction scores.

Results: Data from 80 participants were analyzed. Deeper sedation was induced in the remimazolam group (PGroup × Time < 0.001) despite comparable hemodynamic trends between the groups. The incidence of overall IONV was comparable between the two groups (27.5% in the midazolam group vs. 17.5% in the remimazolam group, absolute risk reduction [ARR]: 0.100, 95% confidence interval [CI] [-0.082, 0.282], P = 0.284); however, newly developed IONV during sedation was significantly reduced in the remimazolam group (20.0% vs. 5.0%, ARR: 0.150, 95% CI [0.009, 0.291], P = 0.043). The need for rescue antiemetics was also lower in the remimazolam group (15.0% vs. 2.5%, ARR: 0.125, 95% CI [0.004, 0.246], P = 0.048).

Conclusion: Remimazolam significantly reduced the incidence and severity of newly developed IONV compared with midazolam, with minimal impact on hemodynamics, making it a useful sedative option for cesarean section.