title: Effect of different pH criteria on dual-sensor pH monitoring in the evaluation of supraesophageal gastric reflux in children.
abstract: OBJECTIVE
  Existing tests for supraesophageal gastric reflux (SEGR) that focus on pH drops <4 in the proximal esophagus have had limited sensitivity and specificity. The aim of the present study was to evaluate the effect of newly proposed pH criteria on SEGR detection.
  
  
  METHODS
  Twenty-four-hour dual-sensor pH tracings of 32 patients were reviewed. Proximal esophageal pH data were evaluated according to the conventional definition of pH drop <4 and 2 proposed definitions: pH drop <5.5 while upright and <5.0 while supine and pH drop of >10% from a running baseline. For each potential SEGR event, the preceding 1-minute window was examined for corresponding distal acid reflux.
  
  
  RESULTS
  Of the 542 distal acid reflux events detected, 200 were associated with a proximal pH drop <4; this number increased to 295 using the definition of proximal pH drop <5.5 (upright)/<5.0 (supine) and 301 using the definition of proximal pH drop >10%. A proportion of proximal events, however, was not associated with distal acid reflux: 21 of 200 (10.5%) proximal pH <4 events, 119 of 414 (29%) proximal pH <5.5 (upright)/<5.0 (supine) events, and 272 of 573 (47%) proximal pH drop >10% events lacked a preceding or simultaneous drop in distal pH <4.
  
  
  CONCLUSIONS
  Although the use of more liberal pH criteria increased the diagnostic yield for SEGR events with dual-sensor monitoring, a significant proportion of proximal pH events did not correlate with distal acid reflux. These events could represent either false-positive measurements or association with weakly acid reflux.
authors.affiliation: Center for Motility and Functional Gastrointestinal Disorders, Children's Hospital Boston, Boston, MA 02155, USA.
authors.forename: Eric
authors.initials: E
authors.lastname: Chiou
authors.forename: Rachel
authors.initials: R
authors.lastname: Rosen
authors.forename: Samuel
authors.initials: S
authors.lastname: Nurko
mesh_terms: D000293:Adolescent; D002648:Child; D002675:Child, Preschool; D003937:Diagnosis, Differential; D050782:Esophageal pH Monitoring / Q000295:instrumentation; D005260:Female; D005764:Gastroesophageal Reflux / Q000175:diagnosis / Q000503:physiopathology; D006801:Humans; D006863:Hydrogen-Ion Concentration; D057045:Laryngopharyngeal Reflux / Q000175:diagnosis* / Q000503:physiopathology; D008297:Male; D016684:Prone Position; D012720:Severity of Illness Index; D016683:Supine Position