Fractionated breath condensate sampling: H 2 O 2 concentrations of the alveolar fraction may be related to asthma control in children

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.