title: Esophagopharyngeal acid regurgitation: dual pH monitoring criteria for its detection and insights into mechanisms.
abstract: OBJECTIVE
  A valid technique for the detection of esophagopharyngeal acid regurgitation would be valuable to evaluate suspected reflux-related otolaryngologic and respiratory disorders. The aim of this study was to derive pH criteria that optimally define esophagopharyngeal acid regurgitation and to examine patterns of regurgitation.
  
  
  METHODS
  In 19 healthy controls and 15 patients with suspected regurgitation, dual or quadruple pH sensors were used to monitor pharyngeal and esophageal pH. For each combination of the 2 variables, DeltapH and nadir pH, proportions of pH decreases that occurred during or independent of esophageal acidification were calculated to determine the likelihood that an individual pharyngeal pH decrease was a candidate regurgitation event or a definite artifact.
  
  
  RESULTS
  Overall, 92% of pharyngeal pH decreases of 1-2 pH units and 66% of pH decreases of this magnitude reaching a nadir pH of <4 were artifactual. Optimal criteria defining a pharyngeal acid regurgitation event were a pH decrease that occurred during esophageal acidification, had a DeltapH of >2 units, and reached a nadir of <4 units in less than 30 seconds. Regurgitation occurred more frequently in subjects in an upright (32 of 35) than in a supine (3 of 35 events; P </= 0.0001) position and was more frequently abrupt (synchronous with esophageal acidification) than delayed (P </= 0.05).
  
  
  CONCLUSIONS
  Accepted criteria for gastroesophageal reflux are not applicable to the detection of esophagopharyngeal acid regurgitation, and most regurgitation occurs abruptly and in upright position.
authors.affiliation: Department of Gastroenterology, Sydney, Australia.
authors.forename: R B
authors.initials: RB
authors.lastname: Williams
authors.forename: G N
authors.initials: GN
authors.lastname: Ali
authors.forename: K L
authors.initials: KL
authors.lastname: Wallace
authors.forename: J S
authors.initials: JS
authors.lastname: Wilson
authors.forename: D J
authors.initials: DJ
authors.lastname: De Carle
authors.forename: I J
authors.initials: IJ
authors.lastname: Cook
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D004947:Esophagus / Q000378:metabolism* / Q000503:physiopathology; D005260:Female; D005764:Gastroesophageal Reflux / Q000175:diagnosis / Q000378:metabolism* / Q000503:physiopathology; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008297:Male; D008365:Manometry; D008875:Middle Aged; D008991:Monitoring, Physiologic; D010614:Pharynx / Q000378:metabolism* / Q000503:physiopathology; D012016:Reference Values; D013997:Time Factors