The authors present the results of a preliminary study designed to define the surgical indications in diffuse pulmonary emphysema based on the data of haemodynamic investigations. This series consists of 10 patients identified for disabling dyspnoea, diffuse emphysema and dynamic expiratory compression documented by the data of right micro-catheterisation by a DEP/DIP ratio greater than 2. The surgical operation consisted of reduction in the lung volume, the results of which were defined by pre- and postoperative examinations. In this way, it is possible to distinguish 3 groups of patients: one group was markedly improved, another was moderately improved and the third group continued to deteriorate analysis of the results suggests the determinant role of dynamic factors, in particular haemodynamic factors. The role of the diaphragm is demonstrated by modifications in its radius or curvature.