Randomized clinical trial of local bupivacaine perfusion versus parenteral morphine infusion for pain relief after laparotomy

Background: Opioids are often used to decrease pain following laparotomy but are associated with unwanted side-effects. The effectiveness of local perfusion of bupivacaine 0.5 per cent following laparotomy was studied. Methods: A prospective randomized study involving patients undergoing laparotomy for major colorectal surgery using a left iliac fossa skin crease incision was undertaken. Patients were randomized to receive either intermittent intravenous morphine infusion on demand with patient-controlled analgesia (PCA group) or continuous wound perfusion of local bupivacaine 0.5 per cent for 60 h (LA group). Results: Seventy patients were recruited, 35 in each group. Patient demographics, surgical and recovery variables and complications were comparable in the two groups. The wound lengths were similar (median 14 cm in both groups). There was no statistically significant difference in postoperative pain scores at rest and with movement between the two groups, except for pain scores at rest on the first postoperative day (P = 0.03). The median total amount of morphine used was significantly greater in the PCA group (median 38 versus 0 mg in the LA group; P < 0.001). Conclusion: Direct continuous local wound perfusion of bupivacaine 0.5 per cent is as effective as PCA for postoperative pain relief after laparotomy. It is a safe and feasible alternative to parenteral opioids.