Comparison of continuous epidural infusion of morphine/bupivacaine with fentanyl/ bupivacaine for postoperative pain relief

The efficacy and safety of postoperative analgesia with continuous epidural infusion of either morphine or fentanyl in combination with bupivacaine were evaluated in 85 patients, ASA physical status I or II, undergoing thoracic and/or upper abdominal surgery. Patients were treated with one of the combinations for 48 h after surgery. The morphine/bupivacaine group (MB; n = 45) received morphine at the rate of 0.2 mg h^-1, and bupivacaine at the rate of 10 mg h^-1 for the first 24 h or 5 mg h^-1 for the second 24 h; the fentanyl/bupivacaine group (FB; n = 40) received fentanyl at the rate of 20 μg–h^-1, and bupivacaine at the rate of 10 mg h^-1 for the first 24 h or 5 mg h^-1 for the second 24 h. The degree of pain relief assessed by the visual pain scale and the modified Prince Henry pain scale was satisfactory in most patients in both groups. In group MB 74% and in group FB 76% of patients did not need any supplementary analgesics. No significant differences were observed between the groups in assessment of pain. The incidence of hypotension ( P < 0.05) and pruritus ( P < 0.05) was higher in group MB than in group FB. None of the patients developed respiratory depression in either group.