[The inert gas method in respiratory physiopathology].

The main results obtained, in healthy or unhealthy man, with the inert gas method are gathered together. The major factor at the source of hypoxemia is the uneven distribution of VA/Q ratios. The fall in the partial pressure of oxygen in mixed venous blood amplifies this effect. Only hypoxemia, during muscular exercise, in patients with interstitial lung diseases could be explained, in part, by a decrease in membrane diffusion and a reduction in the transit time of blood in pulmonary capillaries. The differences between the methods used to analyse pulmonary gas exchange are discussed.