Hypoxic pulmonary steady-state diffusing capacity for CO and alveolar-arterial O2 pressure differences in growing rats after adaptation to a simulated altitude of 3500 m

Summary Steady-state pulmonary diffusing capacity for CO and alveolar-arterial O₂ pressure differences were measured at hypoxia in growing rats adapted to a simulated altitude of 3500 m. The pulmonary diffusing capacity was significantly higher and the alveolar-arterial gradients were significantly lower in the adapted animals as compared with the controls exposed to hypoxia for the first time. The increased diffusing capacity could be explained entirely by the increase of blood O₂ and CO capacity whereas the decrease of gradients might be explained by the increase of blood O₂ capacity together with an increase of the arterio-venous O₂ difference.