DIAMORPHINE BUPIVACAINE MIXTURE COMPARED WITH PLAIN BUPIVACAINE FOR ANALGESIA

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 0.5 mg 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 mi 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. Ho we ver, patients in the diamorphine group had a high incidence of pruritus (44%, compared with 0% in the control group (P < 0.01)).