Background: Asthma is a chronic inflammatory disease of the airways but recent studies have shown that alveoli are also subject to pathophysiological changes. This study was undertaken to compare hydrogen peroxide (H(2)O(2)) concentrations in different parts of the lung using a new technique of fractioned breath condensate sampling.
Methods: In 52 children (9-17 years, 32 asthmatic patients, 20 controls) measurements of exhaled nitric oxide (FE(NO)), lung function, H(2)O(2) in exhaled breath condensate (EBC) and the asthma control test (ACT) were performed. Exhaled breath condensate was collected in two different fractions, representing mainly either the airways or the alveoli. H(2)O(2) was analysed in the airway and alveolar fractions and compared to clinical parameters.
Results: The exhaled H(2)O(2) concentration was significantly higher in the airway fraction than in the alveolar fraction comparing each single pair (p = 0.003, 0.032 and 0.040 for the whole study group, the asthmatic group and the control group, respectively). Asthma control, measured by the asthma control test (ACT), correlated significantly with the H(2)O(2) concentrations in the alveolar fraction (r = 0.606, p = 0.004) but not with those in the airway fraction in the group of children above 12 years. FE(NO) values and lung function parameters did not correlate to the H(2)O(2) concentrations of each fraction.
Conclusion: The new technique of fractionated H(2)O(2) measurement may differentiate H(2)O(2) concentrations in different parts of the lung in asthmatic and control children. H(2)O(2) concentrations of the alveolar fraction may be related to the asthma control test in children.