A longitudinal study of pulmonary function and radiological change has been conducted on 141 nonsmoking coal miners and 256 smoking coal miners from Lorraine, France. At the time of the first examination occasioned by radiological change or shortness of breath, the men averaged between 46.6 years and 50.9 years of age, and they retired approximately 8 years after entering the study. They have been followed for average periods of about 18 years and a mean of five FEV1 observations per man were made over that period. Changes in radiological category have been documented. Average rates of decline of FVC and FEV1 were similar, and varied between -47 ml/yr in nonsmoking miners still alive, to -78 ml/yr in deceased smoking miners. These accelerated rates were similar before and after retirement from the mine.
200 coal miners without any obstructive ventilatory impairment and presenting small opacities of pneumoconiosis were submitted to respiratory function tests including: spirography, CO transfer test by both steady-state and single-breath methods, and arterial blood gas analysis at rest. 38% do not show any significant abnormalities in the different tests. How ever, 9% presented a discrete hypoxemia at rest imputable either to distribution inequalities in 43.5%, to diffusion impairment in 14%, or less frequently to shunt effects.The frequency of diffusion impairment increases with the extent of radiological abnormalities. No radio-functional correlations were observed for distribution inequalities and hypoxemia.
In 31 normal and 378 patients suffering from various bronchopulmonary diseases, a relation was established experimentally between Tco and the alveolo-arterial gradient of CO2. From Tco and CO2 output, this relation allows to obtain a reproducible estimation of the alveolo-arterial gradient and of the arterial pressure of CO2 by a non-bloody method with sufficient clinical accuracy. Moreover, this methods permits to interpret Tco steady state more easily and especially so under unusual ventilatory conditions.
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