Volume capacity and pressure characteristics of the continent ileostomy reservoir.

The volume capacity and the pressure characteristics of the ileal reservoir were studied at intervals postoperatively in 28 patients with continent ileostomy. The reservoir volume increased during the first 6 months from 100 ml to approximately 700 ml, after which it remained stable. The basal pressure increased during filling to a maximum of roughly 10 cm H2O. Under 'physiological conditions' the basal pressure was around 4 cm H2O before emptying. Two types of pressure waves occurred, small pressure fluctuations with a frequency of 7-8/min and larger phasic waves appearing when approximately 40% of the reservoir volume capacity had been reached. The occurrence of both types of pressure waves decreased with time. The total motor activity, expressed as the area underneath the pressure waves, decreased considerably during the 1st year after operation, indicating an adaptation of the intestinal smooth muscle to distension. The results confirm the original concept proposed by Kock that the ileal reservoir constructed in this manner is a low-pressure reservoir.