[Continuous intragastric pH measurement in intensive care patients treated with ranitidine and tube feeding]

We studied 22 critically ill patients on long-term mechanical ventilation using continuous intragastric pH monitoring with an antimony electrode. Intragastric pH profiles were established for the duration of mechanical ventilation (mean: 7 days). The aim of our study was to achieve a gastric pH between 3.0 and 4.5 utilizing the H2-receptor antagonist ranitidine and nasogastric feeding with Nutricomp F. Patients were divided into three groups which were given (A) ranitidine boluses, (B) continuous ranitidine infusions, or (C) continuous ranitidine infusions together with enteral nutrition via the nasogastric tube. In group B we were able to obtain a pH value between 3.0 and 4.5 only in 11.6% of the observation period. With ranitidine boluses, there were even less measurements (9.3%) in the "optimal" pH range. The combination of continuous ranitidine application together with enteral alimentation made our attempts slightly more successful (20.0%). This failure to achieve the desired pH range encourages airway colonisation and nosocomial pneumonia at gastric pH greater than 4.5. At pH less than 3.0 there is a significantly higher incidence of acute stress ulcerations. Other therapeutic regimens e.g. the application of pirenzepine and sucralfate offer adequate protection of the gastric mucosa without raising the pH level.