ESOPHAGEAL pH MONITORING USING A WIRELESS SYSTEM

Abstract

Purpose: Traditional catheter-based esophageal pH testing is limited by patient discomfort, inconvenience, and interference with normal activity during the study. A catheter-free Medtronic (Shoreview, MN) Bravo pH monitoring system has recently become available. The aim of this study was to report our initial experience with this new wireless pH monitoring device. Methods: Medical records of consecutive patients undergoing Bravo pH monitoring at our institution were reviewed. The squamo-columnar junction was located endoscopically and the pH capsule was placed 6 cm above this junction. Patients were re-endoscoped to ensure mucosal attachment. All patients had pH monitoring for 48 hours. Data from a recording device worn by the patient were subsequently downloaded to our system computer for analysis. Results: 42 patients (18M/24F, mean age 48) underwent Bravo pH monitoring between 7/2003 and 4/2004. Indications for the study were heartburn (38%), chest pain (21%), regurgitation (12%), and atypical symptoms (29%). In one patient (2%), the probe did not attach properly. A replacement probe was subsequently placed without difficulty. In 2 cases (5%), data were not retrievable from the recorder secondary to device or computer malfunction. Adequate diagnostic data were obtained in the remaining 40 patients (95%). Of these patients, 53% (21/40) were found to have abnormal esophageal acid exposure, defined as a pH <4 greater than 5% of the time. 38% (16/42) were on proton pump inhibitor during the study. Of these, 13% (2/16) had abnormal acid exposure. On follow-up, 10% (4/42) reported a foreign body sensation or other discomfort in the chest. Subsequent chest x-rays confirmed persistent capsule adherence in 2 of the 4 patients. Symptoms were self-limited in all but one patient, who required endoscopic removal of the capsule at day 5. Conclusions: 1. The technical difficulties associated with Bravo were minimal, and the capsule was well tolerated. 2. Interpretable pH recordings were obtained in 95% of patients. 3. The Bravo pH monitoring system is an effective method of quantifying esophageal acid exposure and can serve as a viable option for patients unwilling or unable to undergo the conventional transnasal pH monitoring system. 4. Future studies are needed to evaluate the cost-effectiveness of this new technology.