Assessment of duodenogastric reflux by combined continuous intragastric pH and bilirubin monitoring

AIM:To assess the diagnostic value of a combination ofcontinuous intragastric pH and bilirubin monitoring in thedetection of duodenogastric reflux(DGR),and the effectsof diet on the bilirubin absorbance.METHODS:30 healthy volunteers were divided into twogroups:standard diet group(Group 1)18 cases,free dietgroup(Group 2)12 cases.Each subjects were subjected tosimultaneous 24 hour intragastric pH and spsctrophotometricbilirubin concentration monitoring(Bilitec 2000).RESULTS:There was no difference of preprandial phasebilirubin absorbance between two groups.The absorbanceof postprandial phase was significantly increased in group 2than group 1.There was no difference between preprandialphase and postprandial phase absorbance in group 1.Postprandial phase absorbence was significantly higher ingroup 2.In a comparison of bile reflux with intragastric pHduring night time,there were 4 types of reflux:Simultaneous increase in absorbence and pH in only 19.6%,increase in bilirubin with unchanged pH 33.3%,pHincrease with unchanged absorbance 36.3%,and bothunchanged in 10.8%.Linear regression analysis showed nocorrelation between percentage total time of pH<4 andpercentage total time of absorbance>0.14,r=0,068,P<0.05.CONCLUSION: Because of the dietary effect, high absorbance fluids or foods should be avoided in detection. Intragastric pH and bilirubin monitoring separately predict the presence of duodenal (and/or pancreatic) reflux and bile reflux. They can not substitute for each other. The detection of DGR is improved if the two parameters are combined simultaneously.