The role of 24-hr gastric pH-monitoring in the interpretation of 24-hr gastric bile monitoring for duodenogastric reflux

BACKGROUND/AIMS: Duodenogastric reflux is a physiologic phenomenon. For a n umber of years, alkalinization of the acidic intragastric pH environment, a s assessed by 24-hour gastric pH-monitoring, was thought to be caused by du odenogastric reflux. The recent introduction of the fotooptic Bilitec syste m for intraluminal bilirubin measurement has created the possibility to dir ectly quantify a component of duodenal juice. METHODOLOGY: In this study, 24-hour gastric pH-monitoring and 24-hour bilir ubin monitoring were performed in healthy subjects. The upper limits for ph ysiologic bile reflux are the percentage of total time of bile reflux of 28 .2% and an average absorbance during a reflux episode of 0.62 (95th percent ile with threshold 0.25). RESULTS: Comparing bile with ps-monitoring (absorbance >0.25 and/or pH >4), sm increase of bilirubin was found most frequently with constant pH (43%) or an increase of pH with constant bilirubin (37%). CONCLUSIONS: The hypothesis was drawn that the composition of duodenogastri c refluxate can vary. Bile and pancreatic juice may separately contribute t o duodenogastric reflux.