Elasticity of the Lung in Pulmonary Emphysema

SUMMARY

The elastic properties of the lung can be described by a curve relating volume of air in the lung to static transpulmonary pressure. In the normal lung these properties are related to surface tension at the air fluid interface in the alveoli and to a lesser extent to the weave of the connective tissue fibers. The elastic tissue fibers appear to play a minor role in determining the elastic properties of the lung. In pulmonary emphysema residual volume is increased, the pressure volume curve is shifted upward, and the maximum static transpulmonary pressure achieved is less than normal. These changes can be produced by diffuse bronchial obstruction, by large poorly ventilated spaces such as bullae, or by diffuse increase in size of air spaces.