Influence of Food, Posture and Gastric Alkaline Events on 24-Hour Gastric and Duodenal pH in Normals

Abstract

We performed simultaneous, ambulatory monitoring of luminal pH in the stomach and in the duodenum in 20 healthy volunteers. The objectives were to determine normal pH ranges and patterns and the influence of food and posture on pH, and to study spontaneous alkaline shifts in the fasting stomach. Antimony electrodes were placed in the antrum and duodenum (second portion) under fluoroscopy. The pH values were recorded every 4 s and the data were analyzed by computer. During daytime and nighttime, when fasting, the gastric pH was generally less than pH 2. Eating increased the peak gastric pH to 4.1 ± 0.2. Alkaline episodes (pH ≧ 4 for 60 s or more) occurred in all subjects frequently in the early morning hours; the mean frequency was 13.3 ± 2.7 per 24-hour period. Duodenal pH was generally neutral (pH > 6 for 66% of the study period). There were 156 ± 20 acid spikes (pH < 4, duration 15 s) per 24 h. Results indicate that long-term, ambulatory pH-metry in stomach and duodenum is possible, that eating and posture do influence pH profiles and that spontaneous alkaline pH shifts regularly occur in healthy individuals.

24‐Hour intragastric pH measurement in the assessment of duodenogastric reflux

“…We have previously used 24-hour pH monitoring to measure intragastric pH [4,5]. Episodes of alkaline shift occurred in the stomach of normal subjects and in patients after biliary or gastric surgery [4,5]. The number of these alkaline episodes increased after gastric or biliary surgery.…”

“…If a pH > 4.0 was taken to indicate duodenogastric reflux this had a sensitivity of 84% compared with either high bile acid or amylase Concentration. Bile acid concentration has been the "standard" method of measuring duodenogastric reflux, pH monitoring is relatively simple to perform, causes little patient distress, and can measure episodes of duodenogastric reflux over a continuous 24-hour period.Duodenogastric reflux (DGR) can occur after gastric [1] or biliary [2] surgery and in patients who have not undergone SUrgery [3][4][5]. Its significance in etiology of symptoms and disease, especially after surgery, is still debated [6] but most authors accept that some symptoms seen in these patients are due to the reflux of duodenal or jejunal fluid into the stomach, and the damage this causes to the gastric mucosa [7].Methods of measurement of DGR include Capper's pyloric regurgitation test [8], the aspiration of gastric fluid and mea-SUrement of its bile acid content [9], and N-(2,6-diethylacetanilido) iminodiacetic acid (HIDA) scintigraphy [10].…”

“…The limitations of HIDA scintigraphy include the test being performed in hospital, restriction on activity, exposure to ISOtope, and a short length of study [10, I ! ].In view of these disadvantages 24-hour intragastric pH monitoring has been suggested as an alternative method for DGR measurement [4,5,12,13]. This technique measures the…”

“…Duodenogastric reflux (DGR) can occur after gastric [1] or biliary [2] surgery and in patients who have not undergone SUrgery [3][4][5]. Its significance in etiology of symptoms and disease, especially after surgery, is still debated [6] but most authors accept that some symptoms seen in these patients are due to the reflux of duodenal or jejunal fluid into the stomach, and the damage this causes to the gastric mucosa [7].…”

“…In view of these disadvantages 24-hour intragastric pH monitoring has been suggested as an alternative method for DGR measurement [4,5,12,13]. This technique measures the…”