We have studied the efficacy of two extradural infusions (10 ml h−1 in 50 patients in active labour. Patients in the diamorphine group (n = 25) received 0.0625% plain bupivacaine 6.25 mg h−1 mixed with 0.005% diamorphine 0.5mg h−1 and those in the control group (n = 25) received 0.125% plain bupivacaine 12.5 mg h−1. Both groups received intermittent “top-ups” of 0.25% bupivacaine 10 ml when indicated. Although median pain scores during the infusion were similar in both groups, patients in the diamorphine group indicated greater satisfaction with the infusion (88% very satisfied, compared with 52% in the control group (P < 0.02)). There were no differences in the incidence of hypotension, instrumental vaginal delivery, number of “top-ups”, duration of the second stage or extent of motor block. However, patients in the diamorphine group had a high incidence of pruritus (44%, compared with 0% in the control group (P < 0.01)). (Br. J. Anaesth. 1994; 72:58–61)

Author notes

†Presented in part at the European Society of Anaes-thesiologists Founding Congress, Brussels, May 1993.