Metoclopramide Reversal of Decreased Gastrointestinal Myoelectric and Contractile Activity in a Model of Canine Postoperative Ileus

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Abstract
Postoperative ileus is characterized by decreased gastrointestinal myoelectric activity and motility. Metoclopramide was used to treat experimentally induced postoperative ileus in six dogs. Contractile activity was monitored by extraluminal strain gages on the pyloric antrum and proximal segment of the duodenum, and myoelectric activity was measured by recording bipolar electromyograms (EMGs) at the pyloric antrum, pyloric canal, proximal segment of the duodenum, proximal and distal parts of the jejunum, and ileum. Measurements were obtained from animals without ileus (baseline) and those with ileus that were either untreated or treated with metoclopramide. Adynamic ileus was induced by rubbing a 50 cm segment of jejunum with a dry sponge for 5 minutes and exposing the bowel to the air for 30 minutes. Treated dogs received metoclopramide (0.4 mg/kg 4 times daily [QID] intravenously [IV]), whereas untreated dogs received a saline placebo, starting 1 hour after celiotomy closure. Recordings were made for 26 hours after induction of ileus. The phases of the migrating myoelectric complex (MMC) were identified and motility index values were determined. During ileus, the MMC phase II duration was increased at the duodenum and phase III duration was decreased at the antrum, pylorus, duodenum, and proximal segment of the jejunum (p < 0.05). Motility index values were decreased at the antrum and duodenum during ileus (p < 0.05). Treatment with metoclopramide reversed the MMC phase III inhibition at the antrum and pylorus, and partially reversed the inhibition at the duodenum and jejunum (p < 0.05). Motility index values were restored to preoperative baseline values with metoclopramide treatment (p < 0.05). Metoclopramide treatment may be beneficial in the treatment of canine postoperative ileus by increasing myoelectric and contractile activity of the proximal gastrointestinal tract.