Comparison of different kinds of tests in the evaluation of lung function among healthy smokers and nonsmokers.

The following groups of lung function tests were performed on 25 healthy male smokers and 25 healthy male nonsmokers. 1) Dynamic function tests: PEF, MMEF, and FEV1/FVC %. 2) Static lung volumes: VC, TLC, FRC, FRC/TLC, and RV/TLC. 3) deltaPco2 was used as a measure of ventilation-perfusion inequalities 4) diffusing capacity was measured with the steady state method described by Filley and coworkers. 5) The blood THb and Tbv were measured. One-way analysis of variance showed that PEF, FEV1/FVC %, and MMEF% were lower (p less than 0.05) in the smoking group. Smokers did not differ from nonsmokers with respect to lung volumes. deltaPco2, THb, and TBV were higher and diffusing capacity lower in the smoking group (p less than 0.001).