title: A new pH catheter for laryngopharyngeal reflux: Normal values.
abstract: OBJECTIVE
  Laryngopharyngeal reflux (LPR) represents a challenging field. Therapeutic studies of proton pump inhibitors in LPR have shown mixed results. The Restech pH catheter (Respiratory Technology Corp., San Diego, CA) is a minimally invasive device for detection of oropharyngeal acid reflux. The aim of this study was to provide normative data using this device in both distal esophagus and oropharynx.
  
  
  METHODS
  Prospective observational study.
  
  
  METHODS
  Normal volunteers were recruited to undergo pH monitoring. A custom made longer catheter was used to assess distal esophageal pH. Oropharyngeal pH catheter was placed at the level of uvula. The distribution of % time was summarized using the 5th, 25th, 50th (median), 75th, and 95th quantiles for pH < 6, pH < 5, and pH < 4 for both upright and supine positions.
  
  
  RESULTS
  A total of 20 normal, healthy volunteers underwent pH monitoring for 14 to 24 hours (median 20.5 hours). The 95th percentile for % total time pH < 4, pH < 5, pH < 6 for the distal esophageal pH catheter were 4.52%, 10.91%, and 42.99%, respectively. For the oropharynx pH probe, the 95th percentile for % total time pH < 4, pH < 5, and pH < 6 were 0.02%, 2.33%, and 21.41% respectively. The 95th percentile for number of reflux events for total pH < 4, pH < 5, and pH < 6 were 1.3, 8.1, and 128.0, respectively.
  
  
  CONCLUSIONS
  Oropharyngeal acid reflux is an infrequent occurrence in healthy volunteers without LPR. The normative data for Restech pH catheter may now be compared to those with suspected LPR.
authors.affiliation: Department of Internal Medicine, Vanderbilt University Medical Center, Nashville, Tennessee 37232-5280, USA.
authors.forename: George
authors.initials: G
authors.lastname: Sun
authors.forename: Srikant
authors.initials: S
authors.lastname: Muddana
authors.forename: James C
authors.initials: JC
authors.lastname: Slaughter
authors.forename: Sean
authors.initials: S
authors.lastname: Casey
authors.forename: Eric
authors.initials: E
authors.lastname: Hill
authors.forename: Farnoosh
authors.initials: F
authors.lastname: Farrokhi
authors.forename: C Gaelyn
authors.initials: CG
authors.lastname: Garrett
authors.forename: Michael F
authors.initials: MF
authors.lastname: Vaezi
mesh_terms: D000328:Adult; D002404:Catheterization; D015331:Cohort Studies; D015154:Esophageal Motility Disorders / Q000175:diagnosis; D050782:Esophageal pH Monitoring / Q000295:instrumentation*; D005260:Female; D005764:Gastroesophageal Reflux / Q000175:diagnosis*; D006801:Humans; D007013:Hypopharynx / Q000503:physiopathology; D008297:Male; D008365:Manometry / Q000295:instrumentation / Q000379:methods; D008991:Monitoring, Physiologic / Q000295:instrumentation* / Q000379:methods; D011446:Prospective Studies; D012016:Reference Values; D012680:Sensitivity and Specificity