[Transmural potential difference of the gastrointestinal tract: its diagnostic value in placing small intestine...

Functional disorders of the upper gastrointestinal tract frequently require the placement of biopsy tubes into the duodenum. At present, monitoring of correct placement of these tubes usually entails the use of x-rays involving a single or repeated exposures. For accurate placement of duodenal tubes, the difference in TPD between the stomach and the duodenum has been employed as a criterion. Measurement of the TPD is technically simple, can be done at the bedside and obviates the need for using x-rays. Suitable hardware and the procedure are described in detail.