Comparison of intramuscular analgesia, intercostal block, epidural morphine and on-demand-i.v.-fentanyl in the control of pain after upper abdominal surgery.

Eighty patients undergoing upper abdominal surgery were randomly allocated to four groups according to the postoperative pain treatment. All patients had a standardized balanced anaesthesia and for postoperative analgesia either intramuscular oxycodone and/or metamizol (IM), intercostal block with 0.5% bupivacaine (IC), epidurally 4 mg morphine (EM) or i.v. infusion of fentanyl 0.54-0.99 micrograms min-1 + on-demand boluses of 7.2-13.5 micrograms (ODAC) were given. The pain intensity 2 h postoperatively was similar in all groups, mean score ranging from 3.2-4.3 on a scale from 0-10. At 24 h also, when additional intramuscular analgesics had been administered if needed, the mean pain scores did not vary much; 2.4 in the ODAC group to 3.4 in the IC group. The time until the first request for additional analgesia was longer in the EM group than in the IM group (7.5 h vs. 3.5 h). There were no differences between the groups in chest X-ray, peak expiratory flow or respiratory rate postoperatively, but in the capillary blood-gas analyses there was a greater number of slightly elevated PCO2 values (6.0-7.3 kPa) in the ODAC group than in the others. The amount of fentanyl infused in 24 h to the ODAC patients varied considerably, 814-2233 micrograms, as did the number of on-demand boluses, 3-155. At 24 h, an efficacy rating "good" was distributed as follows: IM 9/20, IC 11/20, EM 11/20 and ODAC 13/20. In the whole patient material 92.5% rated their condition as "good" or "fair".