title: An oropharyngeal pH monitoring device to evaluate patients with chronic laryngitis.
abstract: BACKGROUND
  Diagnostics for gastro-esophageal reflux disease (GERD) are suboptimal because of limited sensitivity. We performed in vitro and in vivo studies to systematically assess the performance characteristics of an oropharyngeal pH probe.
  
  
  METHODS
  In vitro studies compared the oropharyngeal probe with a standard pH catheter in liquid and aerosolized solutions, pH 1-7. The accuracy of measurements, deviation from target pH, and time to equilibrium pH were determined. Simultaneous distal esophageal pH measurements were obtained in 11 patients with GERD. Oropharyngeal and distal esophageal reflux parameters were measured for controls (n = 20), patients with GERD (n = 17), and patients with chronic laryngitis (n = 10).
  
  
  RESULTS
  In the liquid phase, at pH 4-5, the oropharyngeal probe had less deviation from the target value than the standard catheter; deviation in the vapor phase was similar (0.4 pH units). Median (interquartile) time to reach equilibrium pH was significantly (P < 0.001) faster with the oropharyngeal than the standard probe. In comparing simultaneous distal esophageal pH characteristics, 96% of recordings with the new and standard probes were in agreement to within ± 1.0 pH unit; 71% of recordings were in agreement within ± 0.5 pH units. Patients with chronic laryngitis had significantly higher levels of oropharyngeal acid exposure at pH <4, <5, and <6, in the upright position than patients with GERD or controls (P < .001).
  
  
  CONCLUSIONS
  Oropharyngeal pH monitoring appears to be more sensitive than traditional pH monitoring in evaluation of patients with extraesophageal reflux. It is a promising tool in evaluation of this difficult group of patients.
authors.affiliation: Division of Gastroenterology, Hepatology and Nutrition, Vanderbilt University Medical Center, 1660 TVC, 1301 -22nd Ave. South, Nashville, TN 37232-5280, USA.
authors.forename: E S
authors.initials: ES
authors.lastname: Yuksel
authors.forename: J C
authors.initials: JC
authors.lastname: Slaughter
authors.forename: N
authors.initials: N
authors.lastname: Mukhtar
authors.forename: M
authors.initials: M
authors.lastname: Ochieng
authors.forename: G
authors.initials: G
authors.lastname: Sun
authors.forename: M
authors.initials: M
authors.lastname: Goutte
authors.forename: S
authors.initials: S
authors.lastname: Muddana
authors.forename: C
authors.initials: C
authors.lastname: Gaelyn Garrett
authors.forename: M F
authors.initials: MF
authors.lastname: Vaezi
mesh_terms: D000328:Adult; D050782:Esophageal pH Monitoring / Q000295:instrumentation*; D005260:Female; D005764:Gastroesophageal Reflux / Q000150:complications / Q000175:diagnosis*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007827:Laryngitis / Q000209:etiology; D008297:Male; D008875:Middle Aged; D009960:Oropharynx / Q000737:chemistry*; D015203:Reproducibility of Results; D055815:Young Adult