Studies of paralytic ileus. Effects of intraperitoneal injury on motility of the canine small intestine.

This study is significant in demonstrating that the small intestine of the dog is extremely resistant to paralytic ileus. The various types of intra-abdominal irritation studied were quite severe. After a transient period of inhibition, however, in most instances motility of the small intestine returned and continued until near the time of death. Various types of intra-abdominal irritation were used to study paralytic ileus in dogs, including intraperitoneal injection of gastric juice, gastroperitoneal fistula, appendiceal ligation, intraperitoneal injection of Lugol's iodine solution, retroperitoneal injection of blood, and mechanical and thermal irritation of the intestine and peritoneum. The electrical and mechanical activity of the small intestine was observed by means of a Thomas cannula implanted in the jejunum. The presence or absence of fluid accumulation within the intestinal lumen or peritoneal cavity was noted at autopsy. Intra-abdominal chemical irritation caused a transient inhibition of intestinal motility, which was reversed when the irritation was stopped. Repeated irritation did not appear to cause progressive, irreversible inhibition of intestinal motility. When intestinal motility was depressed, spike potentials were absent in the recordings of electrical activity of the intestine. The "slow" electrical waves were distinguishable at all times. With the exception of the gastroperitoneal fistulas, the procedures were tolerated with only transient inhibition of intestinal motility. Accumulation of intraperitoneal fluid occurred in dogs subjected to gastroperitoneal fistulas. A small amount of intraluminal fluid accumulated in dogs subjected to repeated thermal and mechanical irritation of the intestines and peritoneum. In the other groups of dogs no significant increase in intestinal or intraperitoneal fluid was observed.