INCREASED EXHALATION OF HYDROGEN-PEROXIDE IN PATIENTS WITH STABLE ANDUNSTABLE CHRONIC OBSTRUCTIVE PULMONARY-DISEASE

An imbalance between oxidative stress and antioxidative capacity is th ought to play an important role in the development and progression of chronic obstructive pulmonary disease (COPD). To assess the lung oxida tive status in patients with COPD, we studied whether exhaled hydrogen peroxide (H2O2) is increased in breath condensate of patients with st able COPD (n = 12, mean FEV(1) 51% pred) and in patients with exacerba ted COPD (n = 19, actual FEV(1) 36% pred) compared with a healthy cont rol group (n = 10, FEV(1) 108% pred). Expired breath condensate during 15 min of tidal breathing was collected by cooling. The concentration of H2O2 was measured spectrophotometrically by means of horse radish peroxidase-catalyzed oxidation of tetramethylbenzidine. Concentrations of H2O2 (mean +/- SEM) were significantly elevated at 0.205 +/- 0.054 mu M in patients with stable COPD compared with 0.029 +/- 0.012 mu M in the control group (p < 0.05) and were further increased to 0.600 +/ - 0.075 mu M in patients with acutely exacerbated COPD (p < 0.001 comp ared with patients with stable COPD). Patients with pulmonary infiltra tes on chest radiograph showed similar values compared with patients w ithout obvious infiltrates. These findings demonstrate that patients w ith stable COPD exhibit increased oxidant production in the airways an d that oxidant production increases further during exacerbations.