A single intragastric pH electrode does not accurately measure intragastric acidity

Area of Science:

• Gastroenterology
• Medical Devices
• Clinical Measurement

Background:

• Concerns exist regarding the accuracy of single intragastric pH electrodes for measuring gastric acidity.
• Reproducibility issues have been reported with current pH monitoring techniques.

Purpose of the Study:

• To compare simultaneous intragastric pH measurements.
• To evaluate measurements from an indwelling glass pH electrode against gastric aspirate and ex vivo methods.

Main Methods:

• Twenty-two healthy volunteers underwent fluoroscopically guided nasogastric tube-pH probe placement.
• Simultaneous pH measurements were taken using an electrode and gastric aspirates under fasting, fasting antacid, postprandial, and postprandial antacid conditions.

Main Results:

• Intragastric pH readings were consistently lower with the electrode compared to aspiration.
• Baseline hydrogen ion concentration ([H+]) was 4.3 times higher by electrode than aspiration.
• Correlation coefficients between electrode and aspirate measurements varied significantly across different conditions (p < 0.001 to 0.253).

Conclusions:

• Quantitative intragastric acidity measurements differ significantly between intragastric pH electrodes and gastric aspiration.
• Studies relying solely on single intragastric pH electrodes may produce inaccurate assessments of gastric acidity.