Acute effects of nebulization of N-acetylcysteine on pulmonary mechanics and gas exchange.

Administration of a nebulized 20 per cent solution of N-acetylcysteine to 12 normal subjects caused no change in airway caliber. In 16 patients with obstructive lung disease, however, a bronchospastic reaction immediately followed nebulization of the solution, with changes persisting to a lesser degree at the end of 30 minutes. Acute changes in expiratory airway resistance were not reflected in measurements of forced expiratory volume in one second although changes in inspiratory resistance correlated well with maximal inspiratory flow. Measurement of blood gas exchange in 7 of the patients revealed hypoxia, hypercapnia, and increase of the ratio of dead space to tidal volume in most of them, suggesting further impairment of ventilation-perfusion relationships.