Effects of smoking on dynamic compliance and respiratory resistance.

Acute and chronic effects of smoking were studied in 68 healthy men. Current smokers, exsmokers, and nonsmokers had significantly different maximum expiratory flow rates at low lung volume (V max 25) confirming that smoking chronically impairs small airways function. After smoking one cigarette, respiratory system resistance was increased in all subjects suggesting large airways constriction. Frequency dependence of compliance (FDC) was increased after smoking one cigarette in those subjects who had little baseline FDC regardless of smoking history; these changes were partially reversed by inhalation of metaproterenol. These findings suggest that smoking narrows large airways in all subjects and also small airways in those subjects without small airways disease.