BACKGROUND: Prolonged pH monitoring is used increasingly to assess alterations of gastric luminal pH caused by gastroduodenal secretory and motor abnormalities. The clinical value of gastric pH monitoring, however, has been debated. METHODS: We obtained normal values for 24-hour ambulatory gastric pH monitoring in 50 healthy volunteers and evaluated its clinical use by monitoring pH in 285 consecutive patients with nonspecific foregut symptoms and duodenal ulcers (n = 33), gastric ulcers (n = 21), antral gastritis (n = 123), or no mucosal injury (n = 108). RESULTS: Patients with duodenal ulcer had a shift of their recorded pH values to a more acidic range, particularly during the night (p < 0.01). Multiple regression analysis showed that an increased percentage of time pH was less than 1.2 during the night indicates gastric acid hypersecretion. In contrast, patients with gastric ulcer or antral gastritis had an increased frequency of alkaline peaks and percentage of time spent at a pH greater than 3 (p < 0.01). The presence of excessive duodenogastric reflux was identified in 39% of these patients as compared with 7% with no gastric mucosal injury (p < 0.01). Delayed gastric emptying was suggested by prolonged postprandial alkalinization of the gastric pH record in 25% of the patients. Radionuclide gastric emptying studies confirmed this in 85% of these patients. CONCLUSIONS: Gastric pH monitoring allows evaluation of gastric secretory state fluctuation in gastric pH environment, duodenogastric reflux, and gastric emptying under physiologic conditions during a complete circadian cycle and has potential to be one of the most inclusive initial tests of gastroduodenal function.
BACKGROUND: Prolonged pH monitoring is used increasingly to assess alterations of gastric luminal pH caused by gastroduodenal secretory and motor abnormalities. The clinical value of gastric pH monitoring, however, has been debated. METHODS: We obtained normal values for 24-hour ambulatory gastric pH monitoring in 50 healthy volunteers and evaluated its clinical use by monitoring pH in 285 consecutive patients with nonspecific foregut symptoms and duodenal ulcers (n = 33), gastric ulcers (n = 21), antral gastritis (n = 123), or no mucosal injury (n = 108). RESULTS:Patients with duodenal ulcer had a shift of their recorded pH values to a more acidic range, particularly during the night (p < 0.01). Multiple regression analysis showed that an increased percentage of time pH was less than 1.2 during the night indicates gastric acid hypersecretion. In contrast, patients with gastric ulcer or antral gastritis had an increased frequency of alkaline peaks and percentage of time spent at a pH greater than 3 (p < 0.01). The presence of excessive duodenogastric reflux was identified in 39% of these patients as compared with 7% with no gastric mucosal injury (p < 0.01). Delayed gastric emptying was suggested by prolonged postprandial alkalinization of the gastric pH record in 25% of the patients. Radionuclide gastric emptying studies confirmed this in 85% of these patients. CONCLUSIONS: Gastric pH monitoring allows evaluation of gastric secretory state fluctuation in gastric pH environment, duodenogastric reflux, and gastric emptying under physiologic conditions during a complete circadian cycle and has potential to be one of the most inclusive initial tests of gastroduodenal function.