A comparison of the analgesic efficacy of 0.25% levobupivacaine combined with 0.005% morphine, 0.25% levobupivacaine alone, or 0.005% morphine alone for the management of postoperative pain in patients undergoing major abdominal surgery

We compared the relative efficacy of the combination of the single-isomer local anesthetic levobupivacaine and the opioid analgesic morphine versus both drugs alone for postoperative epidural analgesia after major abdominal surgical procedures. Thoracic epidural anesthesia was produced and maintained with levobupivacaine 0.75% in combination with general inhaled anesthesia without opioids. Patients were randomized to one of three postoperative treatment groups: 1) a combination of levobupivacaine 0.25% and morphine 0.005%; 2) levobupivacaine 0.25%; or 3) morphine 0.005%. Postoperatively, all epidural infusions were commenced at a rate of 4 mL/h. Patients could receive a 4 mL-bolus dose and an increase in the epidural infusion rate by 2 mL/h on request for supplemental analgesia. Patients were also allowed ketorolac as a supplemental analgesic at any time after the first analgesic request. Patients in the combination group had longer times to request for supplemental analgesia as compared with the levobupivacaine only group (P < 0.05) and a trend toward longer time to request as compared with the morphine only group (P = 0.066). Patients in the combination group had lower visual analog scale pain scores at rest and activity at 4 and 8 h and fewer requests for supplemental ketorolac (P < 0.05). In conclusion, this study demonstrates a significant improvement in postoperative analgesic efficacy with the combination of levobupivacaine and morphine for continuous epidural analgesia after major abdominal surgical procedures. IMPLICATIONS: A significant improvement in postoperative analgesic efficacy is demonstrated with the thoracic epidural administration of the combination of the single-isomer local anesthetic levobupivacaine 0.25% and morphine 0.005% in patients after major abdominal surgical procedures as compared with either drug used alone.