Usefulness of catheterless radiotelemetry pH monitoring system to examine the relationship between duodenal acidity and upper gastrointestinal symptoms

Background and Aim: To clarify the usefulness of a newly designed method for measuring intraduodenal pH to examine the relationship between duodenal acidity and upper gastrointestinal symptoms during intragastric acid infusion. Methods: The study subjects were six healthy volunteers. A Bravo pH capsule with thread fixed to the gastric wall was endoscopically introduced into the second portion of the duodenum, and intraduodenal acidity was measured during intragastric infusion of 300 mL of 0.1 mol/L hydrochloric acid or pure water through an elemental diet tube. The severity of several upper gastrointestinal symptoms were assessed by using a 10-cm visual analogue scale every 2 min for up to 30 min, and the area under the severity scale-time curve (cm x min.) were calculated. Results: The percentage time during 30 min when the intraduodenal pH was < 4.0 and was significantly greater than during water infusion (61.4 +/- 6.1% vs 24.8 +/- 6.5%). Several upper gastrointestinal symptoms were observed during acid infusion (acid vs water epigastric heaviness, 29.1 +/- 12.0 vs 2.7 +/- 1.4; dull epigastric pain, 8.8 +/- 4.9 vs 0.7 +/- 0.7 cm x min/30 min). Intraduodenal pH below 4.0 was correlated with the severity of dull pain in the stomach (R2 = 0.342, P = 0.044). Conclusion: The newly designed intraduodenal pH monitoring by using catheterless radiotelemetry system is useful to examine the relationship between duodenal acidity and upper gastrointestinal symptoms.