Continuous infusion of butorphanol combined with intravenous morphine patient-controlled analgesia after total abdominal hysterectomy: a randomized, double-blind controlled trial.

BACKGROUND AND OBJECTIVE: Postoperative pain therapy is still a problem for clinicians. Continuous basal infusion of drugs combined with standard patient-controlled analgesia (PCA) is considered to be an effective means of postoperative acute pain management. This study was designed to investigate the analgesic efficacy, morphine-sparing effects and side effects of butorphanol delivered as a continuous infusion adjunct to intravenous morphine PCA after abdominal hysterectomy.

METHODS: One hundred and eighty-six ASA physical status I-II patients, undergoing total abdominal hysterectomy, were allocated to this randomized double-blind controlled study and assigned to one of two groups. In the butorphanol (n = 96) group, patients received an intravenous loading dose of 10 microg kg(-1) butorphanol followed by infusion of 2 microg kg(-1) h(-1) butorphanol combined with intravenous PCA set at a bolus of 0.02 mg kg(-1) morphine after surgery. The control group (n = 90) received a physiological saline infusion combined with the same morphine PCA. Pain intensity on movement and at rest, sedation, satisfaction with analgesia, morphine consumption and side effects were recorded.

RESULTS: A total of 164 patients completed the study. The butorphanol group had analgesia superior to the physiological saline control (P < 0.001). The butorphanol infusion group produced higher sedation ratings (P < 0.001) and better satisfaction (P < 0.05) and a lower incidence of side effects (P < 0.001) with the exception of sweating and dry mouth (P < 0.05) than the physiological saline group. The butorphanol group consumed less morphine over 48 h, 24.6 mg (95% confidence interval, 18.7-46.6), than the physiological saline group, 58.5 mg (95% confidence interval, 41.5-79.2; P = 0.006). There were no differences between urinary catheterization of more than 24 h, first time out of bed and time to discharge to home.

CONCLUSION: Basal infusion of butorphanol combined with intravenous morphine PCA in patients undergoing abdominal hysterectomy shows effective analgesia with sedation and fewer side effects.