The American Journal of Medicine
Ambulatory Esophageal pH Monitoring
Section snippets
The Technique of Ambulatory pH Monitoring
Prolonged ambulatory monitoring of esophageal pH is the most reliable method for diagnosing GERD. The test involves the placement of a thin pH probe through the nares, which is positioned 5 cm above the manometrically determined lower esophageal sphincter. The probe is connected to a small lightweight box worn on a waistbelt. Data are collected in the box, downloaded into a computer, and graphic and numerical displays can be presented. Patients are allowed to smoke and drink alcohol while
Prevalence of GER by Ambulatory pH Monitoring
Studies in adult asthmatics demonstrate abnormal amounts of acid reflux by 24-hour esophageal pH monitoring in >50% of patients.1, 2This prevalence is 70–80% in patients with associated reflux symptoms and approaches 50%, even in asthma patients denying symptoms of reflux disease.[3]Likewise, large studies in patients with chronic ENT complaints find abnormal acid reflux by 24-hour pH monitoring in 50–80% of patients.2, 4The ENT studies have 2 other important findings. First, considerable
Problems With Ambulatory Esophageal pH Monitoring
Despite its wide availability and documented usefulness in classic GERD, ambulatory pH monitoring has several problems and issues yet to be resolved in diagnosing the extraesophageal complications of GERD. These include (1) the need for dual pH monitoring, (2) artifact and reproducibility, (3) normal values, (4) role in the initial diagnosis, and (5) role in the follow-up of poorly responding patients (Table 1).
Conclusions
Despite the above problems and uncertainties, 24-hour dual pH monitoring with a pH probe in the distal esophagus and hypopharynx is the best single test for identifying patients with extraesophageal complications of GERD. Further studies and technological advancements will resolve the current limitations with pH testing. Outcome studies and cost analyses will help determine whether initial pH testing or testing only in the poorly responding patient is the most cost effective method for using
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