Lactulose hydrogen and [14C]xylose breath tests in patients with ileoanal anastomosis.

To study the intestinal bacterial flora and mouth to pouch transit time after ileoanal anastomosis, lactulose hydrogen and [14C]xylose breath tests were performed on 19 patients with ileoanal anastomosis and J-pouch and 8 patients with conventional ileostomy. Evaluated by the [14C]xylose breath test, patients with ileoanal anastomosis and ileal pouch showed no difference in the bacterial flora of the proximal small bowel when compared with ileostomy patients. The lactulose hydrogen breath test showed a significant rise in breath hydrogen, indicating bacterial overgrowth, in 68% of patients with ileoanal anastomosis but in none with conventional ileostomy (p less than 0.01). It was concluded that this peak in breath hydrogen was produced by the bacteria in the pouch. Thus the lactulose hydrogen breath test can be used to measure mouth to pouch transit time in 2/3 of patients with ileoanal anastomosis. Mouth to pouch transit time was 63 +/- 9 min and it correlated inversely with stool frequency (p less than 0.05).