An Analytic Evaluation of a Mathematical Model for the Effect of Pulmonary Surfactant on Respiratory Mechanics

¹ School of Medicine, University of North Carolina

1. A mathematical model for the transalveolar surfactant pressure developed elsewhere from a statement of conservation of mass, the laws of thermodynamics, and established physiologic phenomenon is discussed.

2. The pressure is a function of the volume history, and a set of constants and constitutes a major contribution of the transpulmonary pressure.

3. The model is tested on a digital computer and is shown to correlate well with experimental surface tension versus area data, quasi-static pressure versus volume results, and to predict a gradual decrease in compliance and increase in pressure with tidal ventilation and return to greater compliance and lower pressure values with a deep breath or sigh.