Bravo Catheter-Free pH Monitoring: Normal Values, Concordance, Optimal Diagnostic Thresholds, and Accuracy

doi:10.1016/j.cgh.2008.08.020

Clinical Gastroenterology and Hepatology

Volume 7, Issue 1, January 2009, Pages 60-67

https://doi.org/10.1016/j.cgh.2008.08.020 Get rights and content

Background & Aims

The Bravo pH capsule is a catheter-free intraesophageal pH monitoring system that avoids the discomfort of an indwelling catheter. The objectives of this study were as follows: (1) to obtain normal values for the first and second 24-hour recording periods using a Bravo capsule placed transnasally 5 cm above the upper border of the lower esophageal sphincter determined by manometry and to assess concordance between the 2 periods, (2) to determine the optimal discriminating threshold for identifying patients with gastroesophageal reflux disease (GERD), and (3) to validate this threshold and to identify the recording period with the greatest accuracy.

Methods

Normal values for a manometrically positioned, transnasally inserted Bravo capsule were determined in 50 asymptomatic subjects. A test population of 50 subjects (25 asymptomatic, 25 with GERD) then was monitored to determine the best discriminating thresholds. The thresholds for the first, second, and combined (48-hour) recording periods then were validated in a separate group of 115 patients.

Results

In asymptomatic subjects, the values measured using a manometrically positioned Bravo pH capsule were similar between the first and second 24-hour periods of recording. The highest level of accuracy with Bravo was observed when an abnormal composite pH score was obtained in the first or second 24-hour period of monitoring.

Conclusions

Normal values for esophageal acid exposure were defined for a manometrically positioned, transnasally inserted, Bravo pH capsule. An abnormal composite pH score, obtained in either the first or second 24-hour recording period, was the most accurate method of identifying patients with GERD.

Section snippets

Technique of Measuring Esophageal Acid Exposure

Esophageal manometry was performed to determine the position of the lower esophageal sphincter (LES). The motility catheter consisted of 8 water-perfused channels with lateral openings placed 5 cm apart and oriented radially 45° from each other. The study was performed with the patient in the supine position. With all recording ports in the stomach, the motility catheter was withdrawn in 1-cm increments every 20 seconds. The position of the LES in centimeters from the nostril was recorded.

Objective 1

to obtain normal values for the first and second 24-hour periods of Bravo recording in a series of 50 asymptomatic volunteers and to assess concordance between the 2 recording periods.

Normal values for the 6 individual components and the composite pH score obtained with the Bravo pH capsule are shown in Table 2. In asymptomatic volunteers, there was excellent concordance for all 6 components and for the composite pH score between the first and second 24-hour recording periods (Table 3).

Discussion

Clinical experience has shown a difference in the values obtained for esophageal acid exposure in normal subjects using the Bravo pH capsule and the conventional naso-esophageal pH catheter.5, 6 Consequently, normal values specific to the manometrically placed Bravo pH capsule and optimal discriminating thresholds to differentiate normal from abnormal esophageal acid exposure needs to be defined for accurate use of the test in the clinical setting. At the present time, studies performed with

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Original article—alimentary tractBravo Catheter-Free pH Monitoring: Normal Values, Concordance, Optimal Diagnostic Thresholds, and Accuracy

Background & Aims

Methods

Results

Conclusions

Section snippets

Technique of Measuring Esophageal Acid Exposure

Objective 1

Discussion

Gastroenterology

Am J Surg

Am J Gastroenterol

Clin Gastroenterol Hepatol

J Gastrointest Surg

Can the combination of symptoms and endoscopy confirm the presence of gastroesophageal reflux disease?

Am Surg

Biology of gastroesophageal reflux disease: pathophysiology relating to medical and surgical treatment

Ann Rev Med

Effect of ambulatory 24-hour esophageal pH monitoring on reflux-provoking activities

Dig Dis Sci

Comparison of the Bravo wireless and Digitrapper catheter-based pH monitoring systems for measuring esophageal acid exposure

Am J Gastroenterol

Original article—alimentary tract
Bravo Catheter-Free pH Monitoring: Normal Values, Concordance, Optimal Diagnostic Thresholds, and Accuracy