Esophageal pH monitoring: methodology, indication and interpretation

Reflux of gastric contents into the esophagus has for long been accepted as a cause of esophagitis, failure to thrive, and anemia. But, at the same time, gastro-esophageal reflux (GER) is recognized as a physiological phenomenon occurring now and then in every one, especially in the postprandial period. Esophageal pH monitoring is an attractive technique for separating "physiological" from "pathological" GER incidence and duration by measuring incidence and duration. In principle, esophageal pH monitoring is simple, but in practice there are technical and clinical problems. The pH monitoring equipment, the type of electrode, the location of the electrode are examples of equipment and/or methodology related influencing factors. Age, position, duration of the investigation (day/night, fasting/postprandial), feeding and drugs are patient related factors. Despite all these factor, pH data have been shown to be reproducible. The major advantages of pH monitoring are that it evaluates GER in (1) physiological circumstances over (2) a prolonged duration. (3) The investigation can be repeated and can therefore (4) evaluate the efficacy of treatment. (5) The possibility of establishing a relation in time between pH changes and symptoms constitutes another advantage of the technique.