Evaluation of intragastric pH in acutely ill patients.

The effect of various modalities on maintaining a high intragastric pH in acutely ill patients was evaluated. Twelve patients with one or more organ system failures had the effect of nasogastric suction, intragastric antacid instillation, and intravenous cimetidine administration on intragastric pH determined by an indwelling, intragastric pH probe. Each therapeutic modality was administered for 12 hours and the order of performance randomized. Nasogastric suction was associated with a constant intragastric pH of less than 2.0. Mean intragastric pH with cimetidine administration was significantly higher than with antacid administration and consistently greater than 5.0. If low intragastric pH represents susceptibility to acute mucosal lesions, cimetidine therapy was more effective than antacids in the doses and frequency of administration used in this study in maintaining a high intragastric pH, and it may be effective in preventing stress ulcer formation.