New esophageal function testing (impedance, Bravo pH monitoring, and high-resolution manometry): clinical relevance

Esophageal testing aims to quantify gastroesophageal reflux or characterize esophageal motility. Reflux monitoring traditionally has been based on the detection of acidic reflux by a transnasal catheter that measures esophageal pH. Recently there have been two major developments in this field: the wireless Bravo pH capsule (Medtronic, Inc., Minneapolis, MN), which allows catheter-free monitoring, and impedance-pH measurement, a catheter-based technique that enables detection of acidic and nonacidic reflux. The assessment of esophageal motility has relied on conventional manometry for many years. Two new procedures also recently became available to assess esophageal motility: high-resolution manometry, which uses many closely spaced pressure sensors and provides spatiotemporal plots of esophageal pressure changes, and impedance manometry, a test that directly measures bolus transit and provides conventional manometric data. The advantages, disadvantages, and clinical importance of these new esophageal tests are discussed in this review.