The miniaturized unit, containing a pH receiver and a small radio transmitter, is attached to the esophageal wall at 5 cm above the lower esophageal sphincter, using a proprietary endoscopic delivery system. Normally patients are unaware of the capsule, although some may feel a mild sensation in the esophagus or chest while eating.
Data on pH levels can be collected without any interference in normal daily activities such as work, exercise, eating, and sleep, and the information is transmitted via telemetry to a pager-sized recording device worn on a belt.
When the data is downloaded via infrared technology from the receiver into a computer, it is analyzed using Medtronics Polygram Net pH software (the same software used to analyze data from their nasal catheter pH monitoring system). The capsule detaches itself from the esophagus, and is passed through the digestive system within seven to 10 days after the initial insertion.
Several studies have shown the advantages of using this miniaturized method of monitoring pH. In a study at Emory University, the Bravo system improved the identification of abnormalities when compared with 24 hour monitoring; it also recorded longer and more frequent reflux episodes. The Bravo was approved by the FDA and has been commercially available since May 2002.
Reimbursement for the Bravo uses the same diagnostic code that was used in the past for pH testing via nasal catheter. Traffas notes that the Bravo pH monitor is gaining increased acceptance. Bravo has grown very rapidly, and there are now 450 centers in the U.S. using it, he stat