title: Airway pH monitoring in patients with suspected obstructive sleep apnoea using the Dx-pH oropharyngeal probe: preliminary report of a prospective cohort study.
abstract: OBJECTIVE
  To investigate the laryngopharyngeal reflux (LPR) episodes and pH values in patients with suspected obstructive sleep apnoea (OSA) using the Dx-pH oropharyngeal probe.
  
  
  METHODS
  Prospective cohort study.
  
  
  METHODS
  Tertiary medical centre.
  
  
  METHODS
  Forty patients with complaint of snoring or suspected OSA were prospectively enrolled to receive full nocturnal polysomnography (PSG). The patients were divided into 2 groups: a simple snorers group if the Respiratory Disturbance Index (RDI) was < 5 and an OSA group if the RDI was ≥ 5.
  
  
  METHODS
  The patients simultaneously received Dx-pH oropharyngeal probe monitoring for 12 h from about 6 pm to 6 am of the next day. The number of LPR events was recorded if the nadir of rapid pH drops was below pH 5.0 and 5.5. The difference of LPR events between the two groups and the difference of LPR events between awake and sleep periods in each group were analysed, respectively.
  
  
  RESULTS
  There were 18 (45%) patients diagnosed as OSA with a mean RDI of 28.7, and 22 patients (55%) diagnosed as simple snorers. Between 2 groups, there were no significant differences in the LPR events and pH values during the awake period, sleep period or overall recording period. Comparison of the LPR events and minimum pH values between the awake period and the sleep period revealed there were no significant differences in either group.
  
  
  CONCLUSIONS
  Using the new sensitive Dx-pH oropharyngeal probe with PSG, we found that OSA does not correlate with a higher incidence of LPR episodes.
authors.affiliation: School of Medicine, National Yang-Ming University, Taipei, Taiwan; School of Speech Language Pathology & Audiology, Chung-Shan Medical University, Taichung, Taiwan; Department of Otolaryngology-Head & Neck Surgery, Taichung Veterans General Hospital, Taichung, Taiwan.
authors.forename: C-C
authors.initials: CC
authors.lastname: Wang
authors.forename: H-C
authors.initials: HC
authors.lastname: Lien
authors.forename: A
authors.initials: A
authors.lastname: De Virgilio
authors.forename: W-C
authors.initials: WC
authors.lastname: Huang
authors.forename: M-F
authors.initials: MF
authors.lastname: Wu
authors.forename: S-A
authors.initials: SA
authors.lastname: Liu
authors.forename: C-P
authors.initials: CP
authors.lastname: Wang
authors.forename: S-H
authors.initials: SH
authors.lastname: Wu
authors.forename: K-L
authors.initials: KL
authors.lastname: Liang
authors.forename: R-S
authors.initials: RS
authors.lastname: Jiang
mesh_terms: D000328:Adult; D000368:Aged; D015331:Cohort Studies; D004784:Environmental Monitoring; D005260:Female; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008297:Male; D008875:Middle Aged; D009960:Oropharynx / Q000502:physiology*; D017286:Polysomnography; D011446:Prospective Studies; D020181:Sleep Apnea, Obstructive / Q000503:physiopathology*