OBSTRUCTION OF THE SMALL AIRWAYS IN THE SPIROMETRIC DIAGNOSIS OF OCCUPATIONAL BRONCHIAL-ASTHMA

The aim of this study was to evaluate spirometric changes after inhala tion challenge in steel and tobacco factory workers suffering from bro nchial asthma suspected to be of occupational origin. In 49 patients t he spirometric changes were analyzed immediately after and 24 h (delay ed reaction) after inhalation challenge at work. A decrease in spirome tric parameters of 20% compared to baseline was considered significant . The suspicion of occupational bronchial asthma was based on anamnesi s and skin patch tests. The atopy features in examined patients were e valuated according to anamnesis, skin prick tests with aeroallergens, as well as total IgE serum level and blood eosinophils. The significan t decrease in spirometric parameters after the inhalation challenge at work was confined in 25 (51%) patients. In 16 of them (64%), the decr ease of FEV1 value together with the decrease of the MEF 25-75% VC val ues were noted A significant isolated decrease in the FEV1 was observe d in only four (16% ) patients. However in five (20%) patients a signi ficant decrease in MEF 25-75% VC values was only found as a confirmati on of airways obstruction. The studies emphasize the diagnostic value of small airways obstruction in the evaluation of inhalation challenge tests in patients suspected of occupational bronchial asthma.