Intramucosal pH and intestinal mucosal damage in ischemia-reperfusion injury

Small bowel transplantation (SBT) has become an increasingly promising treatment for short bowel syndrome. The evaluation of graft viability after SBT, however, has not been established, except by mucosal biopsy. We monitored intestinal mucosal acidity in order to detect small intestinal ischemia-reperfusion injury. Mongrel dogs were used in this study. After laparotomy, the small bowel was isolated with a vascular pedicle. A tonometer to measure intramucosal pH (pHi) was then positioned in the terminal ileum. The superior mesenteric artery was occluded with or without concomitant superior mesenteric vein occlusion for 60 or 120 min. The value of pHi was determined from laparotomy (baseline) to 12 h after reperfusion. Whole-thickness specimens of the ileum were taken before ischemia, just before reperfusion, and 1 h afterward. Mucosal injury was graded histopathologically. pHi decreased from baseline in relation to the degree of histopathological mucosal injury. There was a significant correlation between histological findings and the change in pHi. We conclude that monitoring intestinal mucosal acidity is a reliable way of determining graft viability after SBT.