John T. Sharp

The thorax in chronic obstructive lung disease

Abstract Compliances of the lungs and thorax are normal in chronic obstructive lung disease. However, despite its normal compliance, the overinflated thorax may contribute in a major way to ventilatory failure by being an ineffective inspiratory pump. This effect of the overinflated thorax is predicted by the respiratory pressure-volume diagram of Rahn and associates. The thorax does not become less compliant at lung volumes at or even considerably above the normal total lung capacity. Thus, in emphysema, when lung retractive force is impaired, overinflation is not seriously limited by the elastic recoil of the thorax.