Ambulatory monitoring of GERD: current technology

Various techniques have been devised to diagnose, characterize, and classify gastroesophageal reflux (GER). Stationary techniques, such as fluoroscopy and scintigraphy, provide interesting anatomic and functional information related to GER but are not sensitive enough and are usually performed in nonphysiologic conditions. Ambulatory techniques for GER monitoring have been developed and used since 1974. The current available techniques include catheter and wireless pH-metry, Bilitec, and impedance-pH monitoring. Prolonged wireless pH monitoring can be useful to evaluate patients off and on proton pump inhibitor (PPI) treatment. Impedance-pH monitoring is being used increasingly in patients who have persistent symptoms on PPI therapy because it can establish an association between symptoms and weakly acidic or nonacid reflux. Bilitec is performed in patients suspected to have increased duodenogastroesophageal reflux (DGER). This article discusses the technical details, clinical indications, and applications of these diagnostic techniques.