Cigarette Smoking and Density-Dependence of Maximal Expiratory Flow in Asymptomatic Men1,2

The influence of cigarette smoking on helium response of maximal expiratory flows was studied in 26 asymptomatic male smokers 35 to 55 yr of age. The subjects had smoked 18.0 ± 10.6 cigarettes/day for 19.2 ± 6.7 yr (total consumption, 16.1 ± 9.8 pack/yr) and were selected because they had no history of cardiopulmonary disease, and their physical examination, chest roentgenogram, and spirographic results were normal. Maximal expiratory flow (at the mouth)-volume curves were recorded while the subjects breathed air and a mixture of an 80% helium and 20% oxygen; the helium response (ΔHe) was expressed as the difference between maximal expiratory flow with helium and maximal expiratory flow with air at 50 and 25% of vital capacity. Current cigarette consumption and total tobacco use were not related to either ΔHe50% or ΔHe25%. However, maximal expiratory flows with air and helium were significantly related to current cigarette consumption (for cigarettes/day versus and p < 0.01; for cigarettes/day versus and ...