Objective To observe the effect of butorphanol on the EC50 of ropivacaine during patient-controlled epidural analgesia (PCEA).
Methods Sixty-four patients undergoing radical gastrectomy, 38 males and 26 females, aged 43-58 years, BMI 21-24 kg/m2, ASA physical status Ⅰ or Ⅱ, were randomly divided into 2 groups: ropivacaine group (group R, n = 32) and butorphanol combined with ropivacaine group (group BR, n = 32). All patients underwent epidural puncture and catheterization at T8-9. The epidural analgesia pump in group R was prepared with ropivacaine and normal saline, and in group BR was prepared with ropivacaine, butorphineol 5 mg and normal saline, the volumes in two groups were 100 ml. The concentrations of ropivacaine were measured by sequential method, the initial concentration was 0.1%, and the ratio of adjacent drug concentration was 1.2. EC50 and 95% CI of Ropivacaine were determined by Dixon-Massey method. VAS score < 3 was defined as effective for analgesia, while VAS score ≥ 3 was defined as ineffective for analgesia. The HR, BP, RR and VAS score of patients were recorded 15 min before operation (T0), 1 h (T1), 3 h (T2), 6 h (T3), 12 h (T4), 24 h (T5) and 48 h (T6) postoperatively. Motor block scores were also recorded during PCEA. Postoperative nausea, vomiting and drowsiness were observed and recorded in the two groups.
Results The EC50 of group R was 0.19% (95% CI 0.17%-0.20%). The EC50 of group BR was 0.11% (95% CI 0.10%-0.12%). There was no significant difference in HR, BP, RR and VAS scores between the two groups at each time point. Compared to group BR, the incidences of motor block score of 1 and nausea were higher in group R (P < 0.05).
Conclusion Butorphineol can enhance the analgesic effect of ropivacaine without respiratory depression, pruritus, nausea and vomiting during postoperative PCEA. |
