Comparison of two doses of intrathecal morphine in laparoscopic donor hepatectomy: A randomized double-blinded non-inferiority trial

Background: Intrathecal morphine (ITM) injection is an effective postoperative analgesic strategy in open or laparoscopic donor hepatectomy; however, the optimal dose has not been determined. In this trial, we compared the post-operative analgesic effects of two doses (300 vs. 400 μg) of ITM injections. Methods: In this prospective randomized non-inferiority trial, 56 donors were divided into either the 300 μg or 400 μg ITM group (n = 28, each). The primary outcome was the resting pain score at 24 h postoperatively. Pain scores, cumulative opioid consumption, and side effects (postoperative nausea and vomiting [PONV]) were compared up to 48 h postoperatively. Results: Fifty-five donors participated in the entire study. The mean resting pain scores at 24 h after surgery were 1.7 ± 1.6 and 1.7 ± 1.1 in the ITM 300 and ITM 400 groups, respectively (mean difference, 0 [95% CI, −.8 to.7], p =.978). The upper limit of the 95% CI was lower than the prespecified non-inferiority margin (δ = 1), indicating that non-inferiority had been established. The incidence of PONV was lower in the ITM 300 group than in the ITM 400 group at 18 (p =.035) and 24 h postoperatively (p =.015). There were no significant differences in the resting and coughing pain scores and cumulative opioid consumption at any time point. Conclusion: For laparoscopic donor hepatectomy, preoperative ITM 300 μg exhibited non-inferior postoperative analgesic effects compared to ITM 400 μg, with a lower incidence of PONV.