title: Loss of alkalization in proximal esophagus: a new diagnostic paradigm for patients with laryngopharyngeal reflux.
abstract: BACKGROUND
  Cervical esophageal pH monitoring using a pH threshold of <4 in the diagnosis of laryngopharyngeal reflux (LPR) is disappointing. We hypothesized that failure to maintain adequate alkalization instead of acidification of the cervical esophagus may be a better indicator of cervical esophageal exposure to gastric juice. The aim of this study was to define normal values for the percent time the cervical esophagus is exposed to a pH ≥7 and to use the inability to maintain this as an indicator for diagnosis of LPR.
  
  
  METHODS
  Fifty-nine asymptomatic volunteers had a complete foregut evaluation including pH monitoring of the cervical esophagus. Cervical esophageal exposure to a pH <4 was calculated, and the records were reanalyzed using the threshold pH ≥7. The sensitivity of these two pH thresholds was compared in a group of 51 patients with LPR symptoms that were completely relieved after an antireflux operation.
  
  
  RESULTS
  Compared to normal subjects, patients with LPR were less able to maintain an alkaline pH in the cervical esophagus, as expressed by a lower median percent time pH ≥ 7 (10.4 vs. 38.2, p < 0.0001). In normal subjects, the fifth percentile value for percent time pH ≥ 7 in the cervical esophagus was 19.6%. In 84% of the LPR patients (43/51), the percent time pH ≥ 7 were below the threshold of 19.6%. In contrast, 69% (35/51) had an abnormal test when the pH records were analyzed using the percent time pH < 4. Of the 16 patients with a false negative test using pH < 4, 11 (69%) were identified as having an abnormal study when the threshold of pH ≥ 7 was used.
  
  
  CONCLUSIONS
  Normal subjects should have a pH ≥7 in cervical esophagus for at least 19.6% of the monitored period. Failure to maintain this alkaline environment is a more sensitive indicator in the diagnosis of the LPR and identifies two thirds of the patients with a false negative test using pH <4.
authors.affiliation: 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: Matt
authors.initials: M
authors.lastname: Lilley
authors.forename: Priyanka
authors.initials: P
authors.lastname: Wali
authors.forename: Florian
authors.initials: F
authors.lastname: Augustin
authors.forename: Arzu
authors.initials: A
authors.lastname: Oezcelik
authors.forename: Helen J
authors.initials: HJ
authors.lastname: Sohn
authors.forename: John C
authors.initials: JC
authors.lastname: Lipham
authors.forename: Steven R
authors.initials: SR
authors.lastname: Demeester
authors.forename: Tom R
authors.initials: TR
authors.lastname: DeMeester
mesh_terms: D000328:Adult; D000368:Aged; D050782:Esophageal pH Monitoring; D004947:Esophagus / Q000378:metabolism; D005260:Female; D005764:Gastroesophageal Reflux / Q000175:diagnosis / Q000378:metabolism; D006801:Humans; D057045:Laryngopharyngeal Reflux / Q000175:diagnosis / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D055815:Young Adult