Evaluation of various techniques to monitor intragastric pH

Recent reports emphasized the importance of maintenance of a high intragastric pH to prevent gastric mucosal bleeding in acutely ill patients. In this study gastric fluid pH determinations were compared with determinations obtained using an intragastric pH electrode. There was poor correlation between pH determinations obtained by a bare intragastric electrode in contact with the mucosa and pH determinations on fluid aspirated from the stomach. During cimetidine administration mucosal and fluid determinations correlated well, whereas during antacid administrations correlated well, whereas during antacid administration mucosal pH was significantly lower than gastric fluid pH. These results suggest that during antacid administration pH determinations on gastric contents with pH paper may not accurately reflect the pH at the mucosal surface.