Gastrointestinal pH and transit times in healthy subjects with ileostomy.

Gastrointestinal pH in 11 healthy subjects with ileostomy was determined with a pH-sensitive, radiotransmitting capsule. Median pH was 7.0 in duodenum, dropped to pH 6.3 in the proximal part, but rose to 7.3 in the distal part of the small intestine. In five subjects the pH of the ileostomy effluents was determined with the pH capsule as well as with a pH meter. Median pH was 7.2 measured with the capsule and 7.4 with the pH meter. The difference between the results obtained with the two methods ranged from 0.1 to 0.3 pH units. The median gastrointestinal transit time of the capsule was 10.5 h (range 6.2-12.8 h). Gastric residence time was 0.6 h (range 0.2-3.8 h), and small intestinal transit time was 10.3 h (range 5.6-11.9 h). Thus the small intestinal transit time in ileostomates is slightly increased compared with values reported from studies on subjects with intact gut. However, no statistically significant correlation was found between the small intestinal transit time and the time elapsed after the creation of the ileostomy. We conclude that colectomy does not alter small intestinal pH but seems to increase the small intestinal transit time of single units.