[Bronchial and alveolar NO parameters in smokers].

Our aim was to determine by means of five exhaled flow rates differential parameters of FeNO and the relations between them in smokers and non-smokers. 34 smokers (without respiratory symptoms and medication) were examined. Compared to 43 healthy non-smokers, FeNO was significantly lower. The analysis of the differential NO parameters by means of the two-compartment model of NO production revealed a significant decrease in the bronchial NO concentration, but no significant changes of NO in alveolar fraction by smokers. The relations between differential parameters in non-smokers confirm the theoretical expectations of the two-compartment model. Conversely, smokers exhibit an abnormal remarkable correlation, namely, a high correlation between the reduced C(aw) und FeNO at all five flow rates. It may be assumed that the alveolar NO fraction in smokers is to some extent of bronchial origin. Such a preposition is in line with significantly decreases of FEV(1), FEF(50) and FEF(75) in smokers, which are associated with turbulences, flow inhomogeneity and a varied delay of expiration time from the peripheral airways. We hypothesize that the decreased NO concentration in the bronchial wall of smokers plays a pathophysiological role in the genesis of small airways disease.