Dose-range effects of propofol for reducing emetic symptoms during cesarean delivery.

Abstract

To evaluate the efficacy and safety of propofol at subhypnotic doses for reducing emetic symptoms in parturients undergoing cesarean delivery under spinal anesthesia. In a randomized, double-masked trial, 80 patients received lidocaine intravenously 0.1 mg/kg (for injection pain relief) followed by either placebo or propofol at three different doses (0.5 mg/kg per hour, 1.0 mg/kg per hour, 2.0 mg/kg per hour) (n = 20 in each group) immediately after clamping of the umbilical cord. Emetic episodes and safety assessments were performed during spinal anesthesia for cesarean delivery. To estimate a sufficient sample size, it was calculated that 20 patients per group would be required with alpha =.05 and beta =.2. The rate of patients experiencing no emetic symptoms in an intraoperative, postdelivery period was 45% with propofol 0.5 mg/kg per hour (P =.5), 80% with propofol 1.0 mg/kg per hour (P =.011), and 80% with propofol 2.0 mg/kg per hour (P =.011), compared with placebo (40%). No clinically serious adverse events caused by the study drugs were observed. Propofol 1.0 mg/kg per hour is the minimum effective subhypnotic dose for reducing emetic symptoms during cesarean delivery. Increasing the dose to 2.0 mg/kg per hour provides no further benefit.