Lung gas exchange in simple pneumoconiosis of coal workers.

268-273. Indices of lung function and gas exchange, including some based on measurement of the arterial blood gases and physiological response to exercise, were obtained in 19 coal workers with simple pneumoconiosis of the pinhead or micronodular type, of whom 11 also had bronchitis. p-Type pneumoconiosis differed from the m-type in being associated with a smaller transfer factor, larger physiological deadspace relative to tidal volume (Vd/Vt), and increased ventilation during submaximal exercise. Vd/Vt was also raised in patients with bronchitis. The venous admixture effect (including physiological shunt) was within normal limits. Breathing oxygen increased Vd/Vt in patients with bronchitis but not with p-type pneumoconiosis. The findings are evidence for p-type pneumoconiosis being associated with abnormal function of the lung parenchyma; the changes are consistent with cystic lung.