RELATIONSHIP OF SMOKING HISTORY AND PULMONARY-FUNCTION TESTS TO TRACHEAL MUCOUS VELOCITY IN NON-SMOKERS, YOUNG SMOKERS, EX-SMOKERS, AND PATIENTS WITH CHRONIC-BRONCHITIS

Abstract

Smoking history was related to pulmonary function and tracheal mucous velocity. Groups were defined by smoking history; history of chronic productive cough; the presence of major airway obstruction defined by 1 s forced expiratory volume < 70% of predicted; and signs of small airway obstruction, i.e., combinations of abnormal closing volume, abnormal volume of isoflow, and uneven N2 washout. Tracheal mucous velocity was faster in young than old nonsmokers. Five of 13 (38%) young smokers had tracheal mucous velocity within the range of age-matched nonsmokers, but the remainder had markedly depressed values. Neither smoking history nor pulmonary function distinguished smokers with decreased tracheal mucous velocity from those with normal velocity. Five of 9 (56%) young ex-smokers had values within the range of age-matched nonsmokers, whereas 4 of 9 (44%) ex-smokers had markedly decreased tracheal mucous velocity. Neither smoking history nor pulmonary function distinguished ex-smokers with decreased tracheal mucous velocity from those with normal tracheal mucous velocity. Patients with simple and obstructive chronic bronchitis had markedly decreased tracheal mucous velocity. In selected smokers, tracheal mucous velocity was measured before and within 10 min after smoking 1 cigarette, and there was no consistent change in this parameter. Reduction of tracheal mucous velocity and small airway disease appear to be the earliest signs of functional impairment in cigarette smokers and may present together or separately.