Preoperative analgesia with epidural morphine.

In a prospective double-blind study, we examined the effects of preoperative epidural morphine associated with general anesthesia (GA) on intra- and postoperative analgesic requirements over a 3-day postoperative period. Twenty patients scheduled for major intraabdominal surgery were randomly assigned to two groups: a control group (n = 10) and an epidural group (n = 10) which received an epidural injection of 5 mg of preservative-free morphine in 10 mL of 0.9% saline. Afterward, both groups received the same GA. Postoperative pain relief was achieved with intravenous (IV) boluses of morphine using a patient-controlled analgesia device. We found smaller opioid requirements in the epidural group than in the control group for intraoperative fentanyl (465 +/- 179 micrograms vs 983 +/- 682 micrograms), for postoperative morphine at 12 h (3.1 +/- 3 mg vs 21.4 +/- 13.8 mg) and 24 h (9.1 +/- 6.4 mg vs 20.6 +/- 9.8 mg), and for the cumulated needs over the 3-day postoperative period (37 +/- 24 mg vs 86 +/- 42 mg). The consumption of IV morphine by the control group decreased over time (P < 0.001, r = 0.44), whereas, in the epidural group, consumption remained constant and small during the 3 days. The maximum pain score was significantly lower in the epidural group than in the control group at 24 h (0.65 +/- 2.4 vs 3 +/- 2), at 36 h (0.3 +/- 0.6 vs 3 +/- 2.7), and at 60 h (0.1 +/- 0.3 vs 1.8 +/- 1.2) after surgery. These results suggest that a single epidural injection of 5 mg of morphine before major surgery produces intra- and postoperative pain relief for at least 3 days.