title: Day-to-day discrepancy in Bravo pH monitoring is related to the degree of deterioration of the lower esophageal sphincter and severity of reflux disease.
abstract: BACKGROUND
  The Bravo capsule allows monitoring of esophageal acid exposure over a two-day period. Experience has shown that 24-32% of patients will have abnormal esophageal acid exposure detected on only one of the 2 days monitored. This variation has been explained by the effect of endoscopy and sedation. The aim of this study was to assess the day-to-day discrepancy following transnasal placement of the Bravo capsule without endoscopy or sedation and to determine factors related to this variability.
  
  
  METHODS
  Bravo pH monitoring was performed by transnasal placement of the capsule in 310 patients. Patients were divided into groups based on the composite pH score: both days normal, both days abnormal and only one of the 2 days abnormal. Lower esophageal sphincter (LES) characteristics were compared between groups.
  
  
  RESULTS
  Of the 310 patients evaluated, 60 (19%) showed a discrepancy between the 2 days. A total of 127 patients had a normal pH score on both days and 123 had an abnormal pH score on both days. Of the 60 patients with a discrepancy, 27 were abnormal the first day and 33 (55%) were abnormal the second day. Patients with abnormal esophageal acid exposure on both days had higher degrees of esophageal acid exposure and were more likely to have a defective LES compared to those with an abnormal score on only one day (35 vs. 83%, p=0.027).
  
  
  CONCLUSIONS
  Patients with a discrepancy between days of Bravo pH monitoring have lower esophageal acid exposure. Variability between the 2 days represents early deterioration of the gastroesophageal barrier and indicates less advanced reflux disease.
authors.affiliation: Division of Thoracic Foregut Surgery, Department of Surgery, Keck School of Medicine, University of Southern California, 1510 San Pablo Street, Suite 514, Los Angeles, CA 90033, USA.
authors.forename: Shahin
authors.initials: S
authors.lastname: Ayazi
authors.forename: Jeffrey A
authors.initials: JA
authors.lastname: Hagen
authors.forename: Joerg
authors.initials: J
authors.lastname: Zehetner
authors.forename: Farzaneh
authors.initials: F
authors.lastname: Banki
authors.forename: Florian
authors.initials: F
authors.lastname: Augustin
authors.forename: Ali
authors.initials: A
authors.lastname: Ayazi
authors.forename: Steven R
authors.initials: SR
authors.lastname: DeMeester
authors.forename: Daniel S
authors.initials: DS
authors.lastname: Oh
authors.forename: Helen J
authors.initials: HJ
authors.lastname: Sohn
authors.forename: John C
authors.initials: JC
authors.lastname: Lipham
authors.forename: Tom R
authors.initials: TR
authors.lastname: DeMeester
mesh_terms: D000328:Adult; D002214:Capsules; D016009:Chi-Square Distribution; D049630:Esophageal Sphincter, Lower / Q000503:physiopathology*; D050782:Esophageal pH Monitoring / Q000295:instrumentation*; D005260:Female; D005764:Gastroesophageal Reflux / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008365:Manometry; D008875:Middle Aged; D009296:Nasal Cavity; D018709:Statistics, Nonparametric
chemical_list: D002214:Capsules