Influence of postoperative epidural analgesia with bupivacaine on intestinal motility, transit time, and anastomotic healing.

Epidural application of bupivacaine has been suggested to have a sympatholytic effect on spinal reflex mechanisms that shortens postoperative paralysis and leads to an improved transit time. The influence on anastomitic healing remains controversial. Laparotomy was performed in eight dogs. A short segment of the distal colon was resected and five electrodes were fixed on the serosa to measure the myoelectric activity (e.g., Migrating Myoelectric Complex--MMC). After operation a peridural catheter was placed between L7 and the sacral crest. One milliliter of bupivacaine 0.25% for each 3 kg of body weight was injected every 4 hours. Barium pellets coated in wax were placed into the stomach to allow radiographic representation of transit time. After 5 days the colon anastomosis was resected to measure the bursting pressure. In the peridural analgesia group (PDA) we found one small bowel intussusception and one covered anastomotic leakage. Postoperative PDA led to early and severe myoelectric activity but did not influence the time until the first MMC occurred (44 +/- 0.8 h, PDA; 44.6 +/- 1.5 h,control). Neither the transit time to the colon (50.2 +/- 1.9h, PDA; 51.7 +/- 5.5 h, control) nor the anastomotic healing was influenced (bursting pressure: 176 +/- 21.1 mmHg, PDA; 152 +/- 27.7 mmHg, control). Postoperative epidural analgesia with bupivacaine shortens intestinal paralysis. Early myoelectric activity with a lack of propulsive activity can cause complications like small bowel intussusception. Hence early postoperative enteral nutrition after epidural analgesia is risky. Because the influence of epidural analgesia on propulsive motility remains unclear, it seems reasonable to recommend its limited use in colon surgery.