The effect of antacid on gastric and duodenal bulb acidity.

A small glass pH electrode was positioned in the duodenal bulb and connected to a digital pH meter. The pH registered every half second was stored on a minidiskette with a capacity of 32.400 pH data on a single mini-disc. A microcomputer controlled electrode calibration, data collection, formating and storage. Four patients with duodenal ulcer were given a liquid test meal, and one hour later when gastric and duodenal acidity had reached high levels they were given 10 ml of antacid. From the stored pH data the mean pH and the mean hydrogen ion concentration was calculated. During the 10 min. period before antacid was given gastric pH was on average 1.5 and the duodenal pH on average 4 with a CH+ of 2.500 mumol/. Ingestion of antacid reduced gastric acidity to around pH 3, and the duodenal pH to 6 with a CH+ of 250 mumol/l. This effect of antacid was observed in all subjects, but the degree and the duration of the effect varied very much between the individuals.