Hydrogen peroxide in exhaled breath condensate in asthmatic children during acute exacerbation and after treatment.

BACKGROUND

In asthmatics, the concentration of hydrogen peroxide (H(2)O(2)) in exhaled breath condensate (EBC) has been found to be increased and to be related to airway inflammation.

OBJECTIVE

The aim of this study was to determine whether in children with acute exacerbation, exhaled H(2)O(2) levels could be influenced by treatment and linked to airway obstruction.

METHODS

Twenty-two asthmatic children (mean age 9.4 years, range 6-14) with asthma exacerbation and 12 healthy children (mean age 11.7 years, range 7-15) were enrolled. Concentrations of exhaled H(2)O(2) before and after standard treatment for asthma attack were compared with those of controls and with clinical observation. Asthmatic children and controls underwent spirometry and skin prick tests to common aeroallergens.

RESULTS

Exhaled H(2)O(2) concentrations were significantly higher in children with asthma both before (median 0.273 µM; p < 0.001) and after pharmacologic treatment (median 0.303 µM; p = 0.001) compared to control values (median 0.045 µM). After treatment, exhaled H(2)O(2) concentrations remained significantly higher in children with and without auscultatory wheezing than in controls (p = 0.034 and p < 0.001, respectively). EBC H(2)O(2) levels in asthmatics before treatment did not differ from those after treatment. No correlation was found between H(2)O(2) and forced expiratory volume in 1 s values. All asthmatics but one were atopics.

CONCLUSIONS

In children with acute asthma exacerbation, exhaled H(2)O(2) concentrations in EBC are significantly elevated. In the short-term follow-up, H(2)O(2) levels remain at high levels and are not correlated with lung function or improvement in symptoms.