title: Nasopharyngeal pH and gastroesophageal reflux in children with chronic respiratory disease.
abstract: OBJECTIVE
  The aim of this case-control study was to evaluate the nasopharyngeal pH (NasopH) in children with normal or abnormal pH-metry in two groups of patients; 1) children presenting gastroenterological symptoms; and 2) children with chronic respiratory symptoms.
  
  
  METHODS
  From February 2004 to January 2005, all consecutive patients referred for 24-hour pH-metry and in whom gastroesophageal reflux disease was suspected were enrolled in a prospective study. They were assigned to four groups: gastroenterological symptoms with normal (A) or abnormal (B) pH-metries (GG), and chronic respiratory symptoms with normal (C) or abnormal (D) pH-metries (RG). NasopH was measured for 5 minutes, before the 24-hour test was performed.
  
  
  RESULTS
  Thirty-eight pH-metry tests were included (20 in the RG and 18 in the GG). Abnormal pH-metry results were observed in 11 patients in the GG and in 12 in the RG. NasopH means were 6.3273 and 5.6917, respectively (p<0.0001). Average nasopharyngeal pH was 5.6917 among the 12 RG patients with abnormal pH-metry results and 6.5000 among the remaining eight patients with normal test results (p=0.0006). Analysis of the RG with a receiver operating characteristic (ROC) curve showed pH of 5.8 as cutoff point (sensitivity of 91.7% and specificity of 87.5%). The area below the ROC curve was 0.870.
  
  
  CONCLUSIONS
  Nasopharyngeal pH is significantly lower among patients in the RG presenting abnormal pH-metry results. A 5.8 NasopH has good sensitivity and specificity and can be used as a screening test in patients with chronic respiratory diseases to select those for whom conventional 24-hour pH-metry is indicated.
authors.affiliation: Universidade Federal do Rio de Janeiro (UFRJ), Rio de Janeiro, RJ, Brazil. cjunqueira@superig.com.br
authors.forename: José Cesar da Fonseca
authors.initials: JC
authors.lastname: Junqueira
authors.forename: Francisco José
authors.initials: FJ
authors.lastname: Penna
mesh_terms: D016022:Case-Control Studies; D002648:Child; D002675:Child, Preschool; D002908:Chronic Disease; D005260:Female; D005764:Gastroesophageal Reflux / Q000150:complications / Q000175:diagnosis* / Q000503:physiopathology; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007223:Infant; D008297:Male; D008365:Manometry / Q000379:methods; D011446:Prospective Studies; D012372:ROC Curve; D012140:Respiratory Tract Diseases / Q000150:complications* / Q000503:physiopathology; D012680:Sensitivity and Specificity