Resting gas exchange in nonsmoking bituminous-coal miners with simple pneumoconiosis

Gas exchange at rest under normoxic conditions was studied in 2,297 nonsmoking bituminous-coal miners with and without simple coal workers' pneumoconiosis (CWP). Measurements of arterial oxygen tension (Pao2) and arterial carbon dioxide tension (Paco2) from blood gas samples obtained at rest in the seated position were used to calculate the alveolar-arterial oxygen tension difference, (A-a)Do2, using the classic alveolar-air equation. We then recalculated the (A-a)Do2 using the age-predicted Pao2 for each miner. The difference between the actual and the predicted (A-a)Do2 was measured and the mean difference for each category of simple CWP was analyzed. We found no evidence that the resting gas exchange differs significantly from the age-predicted (A-a)Do2 in the nonsmoking bituminous-coal minor with simple CWP. Likewise, there is no significant change in (A-a)Do2 with change in the category of simple CWP.