Smoking pattern of smokers with and without tobacco-smoke-related lung diseases.

The number of cigarettes smoked, the duration of the smoking habit, and the tar content of the smoke influence the occurrence of tobacco-smoke-related lung diseases, as may also patterns of smoke inhalation. We therefore determined the smoking pattern, especially the time relation between cigarette puff and inhalation, in smokers with and without tobacco-smoke-related lung diseases. On the basis of clinical and radiologic findings as well as pulmonary function tests, 91 smokers were classified as smokers without lung disease, with small airway disease, with simple chronic bronchitis, with obstructive bronchitis, with pulmonary emphysema, and with lung cancer. Smoking and breathing patterns were recorded, using a smoke-flow machine and a strain-gauge belt while the subject smoked a cigarette. Blood levels of COHb were determined before and after smoking. Of the smoking characteristics assessed, puff-inhalation time, puff peak pressure, and the venous difference in COHb level before and after smoking varied significantly among the smoker groups. Puff-inhalation time, reflecting the duration of smoke retention in the mouth, was only 0.08 s (i.e., practically zero) in smokers with pulmonary emphysema and differed significantly from the time in the other groups. This puffing characteristic may be the consequence or the cause of emphysema. If the latter is true, smokers with emphysema may perhaps lack the acute airway response to smoke inhalation that normally protects most smokers from immediately inhaling tobacco smoke.