Comparison of isomolar vs hyperosmolar enteral diets in experimental ileus.

The diarrhea observed after infusing hypertonic enteral alimentation solutions may be due to the high osmolality. We compared Vivonex HN (810 mOsm) to Osmolite (300 mOsm) in two canine ileus models. After having bipolar electrodes implanted in the stomach, duodenum, jejunum, and colon, four dogs sequentially underwent operations to produce intestinal obstruction (SBO) or perforation/peritonitis (PER). The SBO was released and the perforation closed 24 hr later. GI myoelectric activity (MEA) was monitored during the first 4 postoperative days and again on the 10th day to determine steady-state MEA. Fasting MEA was recorded for 1 hr, followed by 1-hr recordings after intragastric cannula infusion of either Vivonex HN or Osmolite. There was no significant difference in MEA produced by Osmolite vs Vivonex at any recording site. The 24-hr postop gastric and small bowel MEA was significantly decreased (p less than 0.05) vs postoperative days 2 to 4 and 10 under both fasting and fed conditions. The ileus operations had no effect on colonic MEA. These data show that SBO and PER cause significant decreases in gastrointestinal MEA for 24 hr. There was no difference in MEA response of Osmolite vs Vivonex HN. These results suggest that infusion of hypertonic enteral alimentation solutions does not produce increases in GI myoelectric responsiveness vs isotonic solutions.