Tracheal Mucous Velocity in Beagles After Chronic Exposure to Cigarette Smoke

Abstract

Tracheal mucous velocity (TMV) was determined in eight purebred beagle dogs exposed to cigarette smoke (100 cigarettes per week) for 13.5 months, and four control dogs. By means of a mask, smoke was administered through both the mouth and nose for 1.5 hours twice daily. The TMV was measured under thiopental sodium anesthesia 24 hours after the last exposure by means of a cinebronchofiberscopic technique. There was a significant decrease in TMV in dogs exposed to cigarette smoke compared with the control animals. Lung compliance and resistance, single breath diffusing capacity, lung volumes, and arterial Po₂, Pco₂, and pH did not differ significantly between the two groups. We conclude that suppression of mucociliary activity associated with cigarette smoking may precede abnormalities of pulmonary function as determined by conventional methods.