24-hour ambulatory dual gastroduodenal pH monitoring. The role of acid in duodenal ulcer disease.

A new system for long-term, 24-hour, ambulatory dual gastroduodenal pH monitoring is described. Eighteen patients with active duodenal ulcers and ten healthy subjects were studied. Simultaneous gastric and duodenal bulb pH were measured during fasting, the ingestion of a solid meal, and for the remainder of the 24-hour period. The gastric pH profile was similar for both groups. There was no significant difference between the fasting duodenal bulb pH of the duodenal ulcer (DU) patients and controls. The daytime and nocturnal duodenal acid exposure was similar for both groups. The meal caused a similar pattern of duodenal acidification in both controls and DU patients, and acid neutralization appeared to be effective in DU patients. The role of acid in the duodenal bulb does not appear to be of primary pathophysiologic importance in duodenal ulcer disease.