H V Fridriksson | PubMed Health

PubMed1986

Reference values for lung function tests in men: regression equations with smoking variables.

Prediction formulas for static and dynamic spirometry, gas distribution, static lung mechanics and the transfer test were derived from measurements in healthy men. The measurements included total lung capacity, residual volume, airways resistance, static elastic recoil pressure of the lung, static compliance, closing volume, slope of the alveolar plateau (phase III), flow-volume variables (including mean transit time) during breathing of air or a helium/oxygen mixture, and conventional spirometric indices. The results from 146 smokers and 124 never-smokers were evaluated separately and combined. For all lung function tests a single regression equation was obtained. The prediction formulas included time-related smoking variables and were valid for both smokers and never-smokers. For many lung function tests, a nonlinear age coefficient resulted in a significant reduction in variance compared with simple linear models. Heavy tobacco smoking influenced most lung function tests less than ageing from 20 to 70 years, but for airways resistance, transfer factor and phase III the opposite was found.

Adult↗

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Reference values for gas exchange during exercise in healthy nonsmoking and smoking men.

The gas exchange at rest and during exercise was measured in 50 healthy men, 25 lifelong nonsmokers and 25 smokers, between 20 and 65 years of age. Arterial blood samples were taken and expired air was collected at rest, supine and sitting, and during graded exercise. Prediction formulas for various gas exchange variables were obtained by multiple regression. Optimal conditions for gas transfer were present at light exercise. The arterial oxygen tension (PaO2) remained approximately constant during exercise, although in individual smokers and nonsmokers it decreased by up to 1.8 kPa (13.5 mmHg) between a workload of 50 W and the maximal workload. The lower limit for PaO2 at maximal exercise was about 10.7 kPa (80 mmHg). The alveolo-arterial difference in oxygen tension (PA-aO2) increased considerably with increased workload, from 1.09 +/- 1.05 kPa at 50 W to 3.1 +/- 0.9 kPa at maximal exercise. Ageing and tobacco smoking were associated with a decrease in PaO2 and an increase in PA-aO2 at rest in the supine position, but at maximal exercise neither PaO2 nor PA-aO2 was significantly influenced by age or tobacco smoking. In contrast, the dead space and total ventilation were increased during exercise by ageing and tobacco smoking.

Adult↗