Abstract
This study describes the effect of cigarette smoking on the bronchial clearance of monodisperse radioactive iron oxide particles in the miniature donkey. Five donkeys were used to study the effect of 18 to 36 cigarettes smoked over a period of one to two hours. The smoke was inhaled through nasal catheters, either directly or through a water trap. Direct exposure to cigarette smoke produced increased amounts of clearance (ie, greater bronchial deposition; and slower clearance rates from both the bronchial tree and the trachea. The water trap, which increased the transit time of the smoke from the cigarette to the lung and probably absorbed water-soluble gases, reversed some of the impairment of clearance, particularly in the trachea, which was produced by cigarette smoking.