Use of breath hydrogen (H2) to quantitate small bowel transit time following partial gastrectomy

The relation between small intestinal transit time and postgastrectomy diarrhea was investigated with a technique which employs the measurement of pulmonary H2 excretion after ingestion of the nonabsorbable sugar, lactulose. Ten postgastrectomy patients with persistent diarrhea had an average small bowel transit time of 35.2 +/- 3 min (S.E.M.), which was significantly (p less than 0.05) shorter than either that of 10 patients without diarrhea (74.6 +/- 5 min) or 40 healthy controls (72.6 +/- 5 min). These decreased transit times appeared to be due to rapid gastric emptying rather than to a primary intestinal abnormality, since the transit of lactulose instilled directly into the jejunum was equally rapid in patients and controls. All postgastrectomy patients with diarrhea failed to absorb a portion of a 100 gm dose of glucose (quantitated by pulmonary H2 measurements), but all patients without diarrhea and 10 healthy control subjects absorbed the entire dose. Constant perfusion studies of the terminal ileum in two patients indicated that glucose absorption was least efficient from the most rapidly moving front of the ingested bolus of glucose. These studies suggest that the diarrhea observed in some postgastrectomy patients is, in part, the result of malabsorption of carbohydrate due to excessively rapid small bowel transit which is secondary to rapid gastric emptying.