The ED50 and ED95 of esketamine for preventing early postoperative pain in patients undergoing laparoscopic cholecystectomy: a prospective, double-blinded trial

Background This study aims to estimate the safety, efficacy, and median effective dose (ED50) of esketamine for preventing early postoperative pain in patients undergoing laparoscopic cholecystectomy. Methods 54 patients undergoing laparoscopic cholecystectomy were prospectively randomized into two groups (group C and group E). Different doses of esketamine were intravenously administered before the skin incision in Group E. The patients in group C received the same dose of saline at the same time. General population characteristics were recorded. The median effective dose (ED50) and 95% effective dose (ED95) were calculated using Dixon’s up-and-down method. Hemodynamic parameters were monitored, and pain intensity was assessed using a visual analog scale. We also recorded the condition of anesthesia recovery period and postoperative adverse reactions. Results The ED50 of esketamine for preventing early postoperative pain was 0.301 mg/kg (95%CI: 0.265-0.342 mg/kg), and the ED95 was 0.379 mg/kg (95%CI: 0.340-0.618 mg/kg), calculated by probability unit regression. Heart rate (HR) was significantly lower in the esketamine group compared to the control at the skin incision ( p < 0.05 ). The total VAS score at resting was significantly lower in the esketamine group compared to the control group during the awakening period ( p < 0.05 ). There was no significant difference between the two groups regarding the incidence of adverse reactions ( p > 0.05 ). Conclusions In this study, esketamine can prevent early postoperative pain effectively. The ED50 and ED95 of esketamine for controlling early postoperative pain were 0.301 mg/kg and 0.379 mg/kg, respectively. Trial registration ChiCTR2200066663, 13/12/2022.