Postoperative epidural morphine, but not epidural bupivacaine, delays gastric emptying on the first day after cholecystectomy.

Abstract

Gastric emptying is delayed during the first days after abdominal surgery. Studies with volunteers have shown that epidural morphine delays gastric emptying but epidural analgesia with bupivacaine does not. The aim of this study was to evaluate whether these differences in healthy volunteers are also found after cholecystectomy when epidural morphine or epidural bupivacaine is used for postoperative pain relief. Eighteen healthy patients were randomly allocated into two groups. Nine patients received postoperative analgesia with epidural morphine and nine with thoracic epidural bupivacaine. Acetaminophen absorption was used as an indirect measure of the rate of gastric emptying, measured 22 hours after surgery and again 4 weeks later, so that each patient served as their own control. During epidural morphine, serum acetaminophen concentrations were lower, and the area under the concentration time curve from 0 to 60 minutes (AUC60) was smaller (p less than 0.02), the maximum serum acetaminophen concentration (Cmax) was lower (p less than 0.05), and the time taken to reach the maximum concentration (Tmax) was longer (p less than 0.01) compared to epidural bupivacaine. There were no statistically significant differences in AUC60, Cmax, and Tmax between the two groups during the control study. Postoperative gastric emptying was significantly delayed after epidural analgesia with morphine compared to thoracic epidural bupivacaine. Compared to the control situation, epidural bupivacaine did not influence gastric emptying.