SummaryThe authors compare the results of functional respiratory exploration and those of right heart catheterism obtained in twelve cases of chronic emphysema. This study allowed them to bring the following points into evidence.Pressure in pulmonary artery was much increased in subjects with severe emphysema (according to Tiffeneau-Drutel’s classification). It was normal in subjects with benign or moderate emphysema.Test of hypoxia(Inspiratory air containing 9%oxygen) causes a great rise of the pulmonary pressure in subjects of the first group, a slight rise in those of the second group.Reoxygenation induces as a rule a drop of the pressure below the initial level. One may suppose that in chronic emphysema, pressure in pulmonary artery in influenced by the oxygen level in alveolar air and by the arterial blood saturation.However when interpreting the results of the functional tests, one must take into account the increases of pressure due to the anatomical lesions of chronic emphysema.The authors have seen that an increase of cardiac Index is far from constant in chronic emphysematous patients.