Fluid filled small bowel loops in gallstone ileus: clinical and experimental observations.

A bowel fluid gas index was developed for the degree of fluid filled distention in small intestinal obstruction, utilizing the proportion of fluid filled versus gas filled loops on plain abdominal films. Comparison of simple distal small bowel obstruction due to adhesions and gallstone ileus demonstrated a significantly higher index in gallstone ileus, indicating more cases of fluid filled distention. In an experimental study, fistulae between the gall bladder and duodenum were fashioned in a series of dogs. Distal small bowel obstruction was then produced in these dogs and in another series of dogs in whom a sham first operation had been performed. The bowel fluid gas index, as evaluated in a double blind study, was significantly higher in dogs with the fistulae and was similar to that in patients with gallstone ileus. The possible mechanism for these observations is proposed.