Gastric exocrine "failure" in critically ill patients: incidence and associated features.

Following the observation that many critically ill patients cannot maintain their gastric juice pH below 4 without treatment a study was performed to measure the gastric juice pH in such patients and relate it to other clinical data. The case notes of 64 patients who had been admitted to the intensive care unit and taken part in two trials of ranitidine treatment were reviewed. During those trials gastric juice was aspirated hourly and the pH and volume measured. In this study the values recorded during a six hour untreated control phase were used. Data on age, diagnosis, treatment, outcome, episodes of hypoxia, episodes of hypotension, and use of inotropic drugs were also reviewed. Full data were available for 61 patients: 27 had a mean baseline pH of greater than 5 during the control phase and 34 a mean baseline pH of less than 5. Significantly more of those with a high pH suffered hypotension (21/27 v 13/34) and received inotropic drugs (16/27 v 8/34). These findings suggest that hypotension in critically ill patients adversely affects gastric exocrine function; prophylaxis with drugs that can improve gastric mucosal blood flow may be more effective than with antacids.