Biomedical subjects

H V Fridriksson

Publications and source records attributed to H V Fridriksson.

4 recordsLinked to original sources

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↗

PubMed1981

Reference values for respiratory function tests in males: prediction formulas with tobacco smoking parameters.

Prediction equations for respiratory function tests were obtained by multiple regression of data from 263 healthy males. The material was evenly distributed in the ages 20-70 years, about one third each of non-smokers, smokers and ex-smokers. Measurements were done of lung volumes (with body plethysmograph), airways resistance, ventilatory capacity including flow-volume registration, gas distribution and closing volume, transfer factor and static elastic recoil pressures of the lung with calculation of static compliance. The parameters age, height, weight, years of tobacco smoking and grams of tobacco smoked each day showed significant correlation with the outcome of the test in most of the respiratory function tests. Therefore a set of basic regression equations including these parameters were calculated. In addition an 'extended' set of equations was calculated for prediction of some tests with inclusion of nonlinear terms and the parameter 'years of abstinence from smoking.' The reduction in variance which followed inclusion of tested parameters was moderate (20-69%). There were significant differences between results of the present study and several previously published regression formulas.

Adolescent↗

PubMed1981

Increased lung stiffness of persons with pleural plaques.

Forty-five men with asbestos-related pleural plaques detected at a health screening centre were investigated with measurement of lung volumes, airways resistance, ventilatory capacity, transfer factor, gas distribution, closing volume and static recoil pressures of the lung. The men were subjectively healthy, had confirmed exposure to asbestos and had normal chest radiograms apart from the presence of pleural plaques. Most of the men had been exposed to small or moderate amounts of asbestos with a mean duration of 39 years since first exposure. Sixty-seven per cent of the men were smokers or ex-smokers. The lung function was evaluated using regression formulas which included smoking variables. The results clearly demonstrate the presence of lung parenchymal involvement with increased stiffness of the lungs and decreased lung volumes. The change in elastic recoil pressure of the lungs, in total lung capacity and residual volume show significant correlation with measures of asbestos exposure and extent of pleural changes. No synergistic effects between tobacco smoking and asbestos exposure on lung function could be demonstrated. Measurements of the static elastic lung recoil (Pst(max) and Cst/TLC) and total lung capacity were the most sensitive tests for separating the pleural plaque carriers from the controls.

Aged↗

PubMedDate not supplied

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↗