24-H comparison between pH values of continuous intraluminal recording and simultaneous gastric aspiration

This study was undertaken to show whether the correlation between pH values indicated by an intraluminal pH electrode and those simultaneously recorded for gastric aspirates is not only linear but also proportional, so that the two measurement techniques can be considered alternative. A 24-h intragastric pH-monitoring with an antimony electrode, to which a nasogastric tube for hourly aspiration of gastric juice was closely attached, was performed on 20 duodenal ulcer patients. Our data show that the slope of the straight line related to 335 pH pairs is virtually equal to 1, whereas the elevation is almost equal to zero, and this result strongly suggests that a proportional relationship exists between intragastric and aspirate pH levels throughout the whole 24-h period. Besides, in the majority of cases (81%) the pH pairs differ by no more than 1 pH unit. It can be concluded that these two pH monitoring methods may be alternative.