Endoscopic measurement of oesophageal transmucosal potential difference in reflux oesophagitis

Oesophageal transmucosal potential difference (PD) was measured in 76 patients during endoscopy. Twelve patients with no symptoms of gastro-oesophageal reflux, and normal oesophageal appearance on endoscopy and mucosal biopsy had a PD of -18.3 +/- 3.8 mV (mean +/- SD). Thirty three patients had reflux symptoms but the oesophagus appeared normal at endoscopy. Eighteen of these patients had reflux change on oesophageal suction biopsies and the PD in the same region of the oesophagus in this group was -18.1 +/- 7.5 mV. In 15 of the patients, mucosal biopsies were normal and the PD in this group was -18.8 +/- 9.9 mV. Thirty one patients had erosive oesophagitis and PD values in this group were markedly reduced. Twenty seven of these patients had PD values less than -10 mV. We conclude that PD measured by our technique is abnormal in erosive oesophagitis but that it is of no value in the diagnosis of mild mucosal damage in patients with reflux symptoms when endoscopic findings are normal.