Studies on small intestinal obstruction. IV. Circulatiory effects of artificial small bowel distension after obstruction.

Feline small-bowel circulation was studied during in vitro homologous perfusion of denervated intestine shortly after release of an in vivo small-bowel obstruction. Blood flow, vascular resistance, capillary filtration, and oxygen consumption were determined. A previous study demonstrated that any microcirculatory impairment accompanying obstruction was rapidly ameliorated after decompression of the bowel. In the present study the specimens were distended in 20 mmHg increments to the 100 mmHg level. Each pressure level was maintained for a 10 minute period. After deflation the specimens were studied for a further 60 minutes. The results indicate that the microcirculation of the previously obstructed intestine reacts to a considerable distension in essentially the same way as does that of non-obstructed intestine. Certain findings suggest, however, that, by way of enhanced distensibility, an obstruction may render the capillary bed more susceptible to a moderate in crease in intra-intestinal pressure, an increase that in itself does not reduce the capillary filtration rate in non-obstucted intestine.