Gastrointestinal myoelectric activity in mechanical intestinal obstruction

Experiments were designed to study the effect of duration of small bowel obstruction (SBO) on rate of recovery of fasting and nonfasting GI myoelectric activity (MEA) in 10 dogs. Two weeks after implantation of a gastric cannula and bipolar silver electrodes in the antrum, duodenum, proximal and midjejunum, terminal ileum, right and left colon, complete SBO was created in the distal ileum. Duration of SBO was 24 hr in group I (five dogs) and 48 hr in group 2 (five dogs). MEA was recorded on 5 consecutive postop days after creating SBO. Water (500 cc) was given via cannula 90 min after release of SBO and on subsequent days after 90 min of fasting MEA recording. Control data were pooled from MEA recordings obtained on 10th and 12th days after electrode implant, each dog serving as its own control. On the day of SBO release there were no significant differences in MEA between groups 1 and 2. Twenty-four hours after SBO release, group 2 fasting and nonfasting jejunal and ileal MEA was significantly decreased vs group 1 and control levels. These significantly decreased jejunal and ileal MEA levels persisted for 48 hr after SBO release. After water by cannula, group 2 antral MEA was significantly less than group 1 and control levels and remained at these low levels for 72 hr after SBO release. Colonic MEA in group 1 and group 2 was not significantly decreased vs control levels. These data suggest that the colon does not play a regulatory role in ileus caused by SBO. These results also imply that prolonged ileus can be avoided by early operation for mechanical SBO.