Quantitative comparisons of mammalian lung pressure volume curves

The deflation pressure-volume curves of the lungs of a wide range of mammalian species were studied to compare their mechanical properties. A monoexponential mathematical function of the form V = Vmax - (Vmax - Vo)e - kp was fitted to the deflation data. It was found that the bulk stiffness index k (approximately 0.12 cm H2O-1) varied little over the 10(5) fold range of animal body weight. This range of k was far smaller than found in man in the presence of pulmonary parenchymal disease. It was concluded that the intrinsic stiffness characteristics of most mammalian lungs are similar.