INFLUENCE OF TIMING ON THE EFFECT OF CONTINUOUS EXTRADURAL ANALGESIA WITH BUPIVACAINE AND MORPHINE AFTER MAJOR ABDOMINAL SURGERY

We have studied the effect of continuous extradural analgesiawith bupivacaine and morphine, initiated before or after colonicsurgery, in a double-blind, randomized study. Thirty-two patientswere allocated randomly to receive an identical extradural blockinitiated 40 min before surgical incision (n = 16) or at closureof the surgical wound (n = 16). The extradural regimen consistedof a bolus of 7 ml of plain bupivacaine 7.5 mg ml^–1 plusmorphine 2 mg and continuous extradural infusion of a mixtureof bupivacaine 7.5mg ml^–1 plus morphine 0.05 mg ml^–1,4 ml h^–1 for 2 h, followed by a continuous extraduralinfusion of a mixture of bupivacaine 2.5mgml^–1 plus morphine0.05 mg ml^–1, 4 ml^–1 h^–1, continued for 72h after operation. In addition, all patients received similargeneral anaesthesia. There was no significant difference inrequest for additional morphine and no significant differencesbetween the groups in pain scores (visual analogue scale orverbal) during rest or ambulation at any time of measurement.These results do not suggest that timing of analgesia with aconventional extradural regimen is of major clinical importancein patients undergoing colonic surgery