title: Assessment of exhaled breath condensate pH in exacerbations of asthma and chronic obstructive pulmonary disease: A longitudinal study.
abstract: BACKGROUND
  Exhaled breath condensate pH has been proposed as a noninvasive marker of airway inflammation. However, due to standardization difficulties in pH measurement techniques, different pH readings were obtained in previous studies.
  
  
  OBJECTIVE
  In this longitudinal study we assessed condensate pH in patients with an exacerbation of asthma or chronic obstructive airway disease using the very precise carbon dioxide standardization method that negates the effect of this gas on condensate acidity.
  
  
  METHODS
  Condensate pH, fractional exhaled nitric oxide, lung function, and blood gases were measured in 20 nonsmoking patients with asthma and 21 smoking and 17 ex-smoking patients with chronic obstructive airway disease first at hospital admission due to an acute exacerbation of the disease and again at discharge after treatment. Condensate pH was also assessed in 18 smoking and 18 nonsmoking healthy control subjects.
  
  
  RESULTS
  In patients with asthma, condensate pH was significantly decreased at the time of exacerbation compared with nonsmoking control subjects and increased with treatment. In patients with chronic obstructive airway disease, condensate pH remained unchanged during exacerbation, both in smokers and ex-smokers. Nevertheless, condensates collected from smokers were more acidic than those of ex-smokers. A similar difference was observed between smoker and nonsmoker healthy control subjects. No correlations were found between condensate pH and fractional exhaled nitric oxide or lung function variables measured either at admission or discharge.
  
  
  CONCLUSIONS
  Our data suggest that exacerbation of asthma, but not chronic obstructive airway disease, is associated with acidification of breath condensate.
authors.affiliation: Department of Pathophysiology, National Koranyi Institute of TB and Pulmonology, Budapest, Hungary. antbal@net.sote.hu
authors.forename: Balazs
authors.initials: B
authors.lastname: Antus
authors.forename: Imre
authors.initials: I
authors.lastname: Barta
authors.forename: Tamas
authors.initials: T
authors.lastname: Kullmann
authors.forename: Zsofia
authors.initials: Z
authors.lastname: Lazar
authors.forename: Marta
authors.initials: M
authors.lastname: Valyon
authors.forename: Ildiko
authors.initials: I
authors.lastname: Horvath
authors.forename: Eszter
authors.initials: E
authors.lastname: Csiszer
mesh_terms: D000388:Air / Q000032:analysis*; D001249:Asthma / Q000378:metabolism* / Q000503:physiopathology; D001784:Blood Gas Analysis; D001944:Breath Tests / Q000379:methods*; D045853:Exhalation; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008297:Male; D008875:Middle Aged; D009569:Nitric Oxide / Q000032:analysis*; D029424:Pulmonary Disease, Chronic Obstructive / Q000378:metabolism* / Q000503:physiopathology; D012008:Recurrence
chemical_list: D009569:Nitric Oxide