Basal and maximum acid output after continuous overnight gastric aspiration.

Basal and maximum acid outputs were measured on two occasions in a group of 15 duodenal ulcer (DU) patients in remission. The initial study was carried out after a nocturnal acid collection, whereas the second was carried out in the conventional manner without preceding nocturnal aspiration. No difference in the basal acid output, concentration, or volume of secretion was found between the two study days. Maximum acid output on the other hand, was significantly (p less than 0.02) reduced from 30.9 (14.2-41.2) mmol/h, median (+range), to 23.7 (8.1-33.7) mmol/h after overnight aspiration. The reduction in maximum acid output was attributable to a fall in the volume of gastric secretion from 280 (170-371) ml to 230 (142-280) ml. No fall in acid concentration was seen. We conclude that overnight gastric aspiration does not affect basal gastric secretion, but reduces the maximum acid output as a result of a reduced secretory volume.