Continuous epidural butorphanol relieves pruritus associated with epiduralmorphine infusions in children

We examined the efficacy of epidural butorphanol to either prevent or relie ve pruritus associated with epidural morphine infusion in children. Forty-s ix children were randomized to receive either epidural morphine (M) or epid ural M with butorphanol (B) for postoperative analgesia. They received bupi vacaine and either M 50 mu g.kg(-1) or the same dose of M plus B 10 mu g.kg (-1). Following surgery, a continuous infusion of 0.1% bupivacaine with eit her M 20 mu g.ml(-1) or M 20 mu g.ml(-1) + B 4 mu g.ml(-1) was given at a r ate of 0.3 ml.kg(-1).h(-1). Pain scores and pruritus scores were recorded e very 4 h during epidural infusion. Subjects with a pruritus score=2 receive d diphenhydramine 0.5 mg.kg(-1) i.v. and were switched to an alternate epid ural infusion; subjects receiving M (group M) were switched to M+B while su bjects receiving M+B (group B) were switched to hydromorphone (H) 4 mu g.ml (-1). There was no difference in the initial incidence of pruritus (group M 11/18; group B 13/28). No subject in group M required a second change of e pidural infusion because of continued pruritus after being switched to M+B; five of 13 subjects in group B continued to experience pruritus after bein g switched to H and required a second change of epidural infusion or an alt ernate analgesic modality (P=0.038). The median pruritus score in the first 24 h after changing epidural infusions was 0 in subjects in group M Delta (changed from M to M+B) and 1 in subjects in group B Delta (changed from MB to H; P=0.012). While the median sedation score in the first 24 h was 1 i n both groups, there was a greater incidence of sedation scores of 2 in gro up B than group M (28% vs 12.3%; P=0.021). B 10 mu g.kg(-1) was not effecti ve in preventing pruritus associated with bolus epidural administration of M 50 mu g.kg(-1) in children. B 1.2 mu g.kg(-1).h(-1) was effective in reli eving pruritus associated with continuous epidural infusion of M 6 mu g.kg( -1).h(-1).