title: pH in expired breath condensate of patients with inflammatory airway diseases.
abstract: Endogenous airway acidification, as assessed by pH in expired breath condensate, has been implicated in asthma pathophysiology. We measured pH in breath condensate of patients with inflammatory airway diseases in stable condition and examined its relationship with the inflammatory process (as assessed by differential cell counts in induced sputum), oxidative stress (as assessed by H(2)O(2) and 8-isoprostane), and nitric oxide metabolism (as assessed by total nitrate/nitrite). We studied 40 patients with bronchial asthma (20 with moderate disease, forced expiratory volume in 1 second 60 [10]% SD predicted), 20 patients with bronchiectasis, 20 patients with chronic obstructive pulmonary disease (COPD), and 10 normal subjects. Mean (95% confidence intervals) pH values were significantly lower in patients with COPD and bronchiectasis compared with patients with asthma and control subjects (7.16, 7.09-7.23 and 7.11, 7.04-7.19 versus 7.43, 7.35-7.52 and 7.57, 7.51-7.64, respectively, p < 0.0001). Patients with moderate asthma had significantly lower values compared with mild and control subjects. In patients with COPD and bronchiectasis, the values of pH were significantly correlated with both sputum neutrophilia and oxidative stress. Respectively, in patients with moderate asthma, a significant correlation was observed between pH and sputum eosinophilia, total nitrate/nitrite, and oxidative stress. The pH of the expired breath condensate might be a simple, noninvasive, inexpensive, and easily repeatable procedure for the evaluation of the inflammatory process in airway diseases.
authors.affiliation: Department of Pneumonology and Clinical Research Unit, Athens Army General Hospital, Athens, Greece.
authors.forename: Konstantinos
authors.initials: K
authors.lastname: Kostikas
authors.forename: Georgios
authors.initials: G
authors.lastname: Papatheodorou
authors.forename: Konstantinos
authors.initials: K
authors.lastname: Ganas
authors.forename: Konstantinos
authors.initials: K
authors.lastname: Psathakis
authors.forename: Panos
authors.initials: P
authors.lastname: Panagou
authors.forename: Stelios
authors.initials: S
authors.lastname: Loukides
mesh_terms: D000328:Adult; D000368:Aged; D000704:Analysis of Variance; D001249:Asthma / Q000175:diagnosis* / Q000503:physiopathology; D001944:Breath Tests; D001987:Bronchiectasis / Q000175:diagnosis* / Q000503:physiopathology; D016022:Case-Control Studies; D016001:Confidence Intervals; D005260:Female; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011336:Probability; D011379:Prognosis; D011446:Prospective Studies; D029424:Pulmonary Disease, Chronic Obstructive / Q000175:diagnosis* / Q000503:physiopathology; D012016:Reference Values; D012129:Respiratory Function Tests; D012680:Sensitivity and Specificity; D012720:Severity of Illness Index; D013183:Sputum / Q000737:chemistry; D018709:Statistics, Nonparametric