CONTRIBUTION OF GASTROINTESTINAL TRANSIT AND POUCH CHARACTERISTICS INDETERMINING POUCH FUNCTION

Aim-To determine the contributions of gastrointestinal transit and pou ch characteristics to bowel frequency in patients with an ileoanal res ervoir and no pouchitis. Methods-Twenty one patients who had undergone restorative proctocolectomy, with ileostomy closure at least eight mo nths previously, and who had no history of pouchitis were recruited. T hey were prospectively classified on the basis of their bowel frequenc y: 11 patients had good pouch function (bowel frequency less than six per day) and 10 had poor function (bowel frequency more than six per d ay). Gastrointestinal transit was studied using a dual isotope techniq ue and anal and pouch physiological examination was performed on all p atients. Results-Lag phase, 25% and 50% gastric emptying, small bowel transit time, and 10% and 50% pouch filling times, all for solids and Liquids, were not significantly different between patients with good a nd poor function. Anal manometry and pouch and anal electrical sensiti vity were also similar in the two groups. The volume of air and water required to elicit an initial sensation and the urge to defaecate were similar in both groups, but the maximum tolerated volume to both air (525 v 245 ml, good v poor function, median values) and water (625 v 3 70 ml) infusion was significantly (both p < 0.02) lower in patients wi th poor function. Conclusion-Maximum tolerated volume in the pouch, wh ich may reflect pouch size, sensitivity, compliance, or a combination of these is the major determinant of pouch function. Gastrointestinal transit does not seem to be an important determinant of function.