Effects of exercise on pulmonary gas exchange and oxygen transport in chronic obstructive pulmonary diseases

The effect of exercise on pulmonary gas exchange, arterial oxygenation, oxygen transport and delivery, and hemodynamics are studied in 100 patients with chronic obstructive pulmonary diseases. According to the change of PaO2 or PaCO2 induced by exercise, patients were divided into two groups. Group A (n = 52) had significantly increased of PaO2 with little change in PaCO2. Mixed venous PO2, oxygen transport and coefficient of oxygen delivery decreased while the alveolar-arterial PO2 gradients and venous admixture increased significantly in Group B as compared with these parameters in Group A during exercise. Our data imply that exercise may lead to marked deterioration of pulmonary gas exchange, arterial oxygenation, oxygen transport and hemodynamic abnormalities in patients in whom PaO2 is decreased during exercise.