Effect of nitrogen dioxide on exercise-induced bronchial asthma and the sensitivity of the respiratory tract to methacholine

• Published in: Pneumologie (Stuttgart, Germany) Vol. 44 Suppl 1; p. 352
• Main Authors: Jörres, R, Boerger, S, Magnussen, H
• Format: Journal Article
• Language: German
• Published: Germany 01-02-1990
• Subjects: Adult; Air Pollutants - adverse effects; Airway Resistance - drug effects; Asthma - chemically induced; Asthma, Exercise-Induced - chemically induced; Bronchial Provocation Tests - methods; Female; Humans; Male; Methacholine Chloride; Methacholine Compounds; Nitrogen Dioxide - adverse effects
• ISSN: 0934-8387

In patients with bronchial asthma, airway hyperreactivity may be further increased by exposure to low concentrations of nitrogen dioxide. We studied the effect of inhaled nitrogen dioxide in 11 patients with bronchial asthma who presented with normal lung function values. On two different days, 20 min tidal breathing of either filtered air or 0.25 ppm nitrogen dioxide was followed by bicycle exercise (average minute ventilation 30 l/min). One hour after the end of exercise, we performed a methacholine provocation challenge and determined PC100SRaw. The methacholine provocation challenge was repeated on another day (control day). Mean (SEM) SRaw increased by 79.8 (23.8) % and 82.4 (24.9) % after breathing of filtered air and nitrogen dioxide during exercise, respectively (n.s.). Mean (SEM) PC100SRaw was 0.409 (0.205), 0.407 (0.201) and 0.455 (0.181) mg/ml after breathing of filtered air, nitrogen dioxide and on the control day, respectively (n.s.). We conclude that in mild asthmatics short-term exposure to 0.25 ppm nitrogen dioxide does not enhance airway responsiveness to exercise or methacholine.