Bupivacaine decreases epidural meperidine requirements after abdominal surgery

Purpose

The purpose of this study was to determine the optimal of three concentrations of bupivacaine (0.0%. 0.05%. 0.10%) to add to an epidural infusion of mependine (1 mg· ml¹) for postoperative pain relief.

Methods

In this prospective, double blind study. 60 patients undergoing abdominal surgery with general anaesthesia were randomized into three groups to receive for postoperative epidural analgesia: 1) 1 mg· ml¹ mependine (0% group). 2) bupivacaine 0.05% and 1 mgml mependine (0.05% group). 3) bupivacaine 0.10% and 1 mg· ml mependine (0 10% group). Postoperatively, the epidural infusion rate was titrated to produce adequate analgesia and pain was assessed at rest and on movement.

Results

There were no differences in demographic data, average pain scores or side effects among the three groups. However, there was improvement of pain relief at rest over time in the three groups (P< 0.05). Postoperative epidural analgesic infusion rates increased over time 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·hr¹) (P< 0.05). More than half of the 0% group had serum mependine concentrations >400 g· L^?1 to control moderate postoperative pain.

Conclusion

Although analgesia was identical among groups, the lower serum concentrations of mependine support the addition of bupivacaine 0.10% to mependine when administered as a continuous infusion following abdominal surgery.