title: Laryngopharyngeal reflux identified using a new catheter design: defining normal values and excluding artifacts.
abstract: OBJECTIVE
  To define normal values for laryngopharyngeal reflux using an improved catheter design with adjustable electrode placement for pH monitoring.
  
  
  METHODS
  Cohort study of normal volunteers.
  
  
  METHODS
  The setting was an institutional-based gastroenterology practice. Subjects included 20 healthy volunteers with no history of laryngeal, pharyngeal, or reflux symptoms. These included 10 men and 10 women (mean age, 33 y; age range, 26-49 y). Ambulatory 24-hour triple-electrode monitoring of pH in distal esophagus, proximal esophagus, and pharynx using new bifurcated probe was performed. The distal electrode was placed 5 cm above the lower esophageal sphincter, with the proximal two electrodes straddling the upper sphincter. The main outcome measure was the number of true pharyngeal reflux episodes.
  
  
  RESULTS
  Sixteen of 20 subjects had no episodes, and 2 subjects had only one episode of pharyngeal reflux. The two subjects exceeding this value (8 and 15 episodes, respectively) had abnormal distal and proximal esophageal reflux. Artifacts for pharyngeal reflux due to acidic meals or "pseudoreflux" were excluded. Subject tolerance of this new probe was excellent.
  
  
  CONCLUSIONS
  The triple-electrode bifurcated adjustable pH probe provides a well-tolerated technique to identify true hypopharyngeal acid reflux episodes. When artifacts produced by meals and pseudoreflux are excluded, 90% of normal subjects show no episodes or a single episode over a 24-hour period.
authors.affiliation: Graduate Hospital, Philadelphia, Pennsylvania, USA.
authors.forename: Anastasia
authors.initials: A
authors.lastname: Maldonado
authors.forename: Linda
authors.initials: L
authors.lastname: Diederich
authors.forename: Donald O
authors.initials: DO
authors.lastname: Castell
authors.forename: R M
authors.initials: RM
authors.lastname: Gideon
authors.forename: Philip O
authors.initials: PO
authors.lastname: Katz
mesh_terms: D000328:Adult; D000368:Aged; D016477:Artifacts; D002404:Catheterization; D004435:Eating; D004566:Electrodes; D004867:Equipment Design; D004947:Esophagus / Q000378:metabolism; D005260:Female; D005764:Gastroesophageal Reflux / Q000150:complications*; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007818:Laryngeal Diseases / Q000175:diagnosis* / Q000209:etiology; D008297:Male; D008875:Middle Aged; D018670:Monitoring, Ambulatory; D010608:Pharyngeal Diseases / Q000175:diagnosis* / Q000209:etiology; D010614:Pharynx / Q000378:metabolism