BUPIVACAINE DECREASES EPIDURAL MEPERIDINE REQUIREMENTS AFTER ABDOMINAL-SURGERY

Purpose: The purpose of this study was to determine the optimal of thr ee concentrations of bupivacaine (0.0%, 0.05%, 0.10%) to add to an epi dural infusion of meperidine (1 mg.ml(-1)) for postoperative pain reli ef. Methods: in this prospective, double blind study, 60 patients unde rgoing abdominal surgery with general anaesthesia were randomized into three groups to receive for postoperative epidural analgesia: 1) 1 mg .ml(-1) meperidine (0% group), 2) bupivacaine 0.05% and 1 mg.ml(-1) me peridine (0.05% group), 3) bupivacaine 0.10% and 1 mg.ml(-1) meperidin e (0.10% group). Postoperatively, the epidural infusion rate was titra ted to produce adequate analgesia and pain was assessed at rest and on movement. Results: There were no differences in demographic data, ave rage pain scores or side effects among the three groups. However, ther e was improvement of pain relief at rest over time in the three groups (P < 0.05). Postoperative epidural analgesic infusion rates increased overtime for the three groups (P < 0.05) and were lower in the 0.10% group (mean of 10.0 ml.hr(-1)) than in the 0% group (mean of 12.6 ml.h r(-1)) (P < 0.05), More than half of the 0% group had serum meperidine concentrations > 400 g.L(-1) to control moderate postoperative pain. Conclusion: Although analgesia was identical among groups, the lower s erum concentrations of meperidine support the addition of bupivacaine 0.10% to meperidine when administered as a continuous infusion followi ng abdominal surgery.