Effect of Prophylactic Epidural Morphine or Bupivacaine on Postoperative Pain after Upper Abdominal Surgery

Abstract

Morphine 2 and 4 mg or bupivacaine 50 mg (another 50 mg 4 h later) was administered into the epidural space prior to general anesthesia of 40 patients undergoing upper abdominal surgery. During anesthesia, additional analgesics were not given. In the recovery room (4 h) the pain score (0-10) was lowest in the bupivacaine group (mean 2.4), followed by the 4-mg morphine group (4.1), 2-mg morphine group (5.3) and control group (5.7). Half of the patients of the bupivacaine group and those of the 4-mg morphine group needed no analgesics in the recovery room. Later, in the ward (until next morning 0.700 h), only morphine patients (5/20) managed without postoperative analgesics. The mean number of requests for analgesics during that time was as follows: 4-mg morphine, 1.3; 2-mg morphine, 1.9; bupivacaine, 2.7; and control, 2.9. Episodes of hypotension and nausea were most frequent in the bupivacaine group. No serious respiratory complications occurred; 4 h after anesthesia 3 patients in the 4-mg morphine group and 2 in the bupivacaine group had capillary PCO2 [partial pressure of CO2] values > 6.65 kPa [kilopascals] (50 mm Hg), the highest being 7.1 kPa. In 2 additional patients with choledochal drainage (T-tube), the intracholedochal pressure rose to .apprx. 2 kPa (15 mm Hg) and 2.7 kPa after epidural injection of 2 and 4 mg, respectively. A pressure peak was reached within 10 min, and at 75 min the pressure was still 0.7-1.3 kPa above the initial level.