Mathematical development of a comprehensive model of the human pulmonary system: mechanics and ventilation

A comprehensive mathematical model of pulmonary mechanics and regional ventilation is developed. The system is driven by individually controllable muscular forces representing the thoracic and diaphragm-abdomen muscle complexes. The bronchial tree is treated as a system of bifurcating always displaying nonlinear resistance. Elastance of both muscular and alveolar tissues are treated as nonlinear functions of lung volume on a regional level. The model is capable of simulating the effects of the geometric distribution of the mass of the chest, diaphragn and abdomen on the pleural pressure and the effect of the hydrostatic pressure gradient in the pleural fluid on regional alveolar volumes for any body orientation with respect to any gravitational field. Both passive and forced breathing are simulated and examined in terms of commonly used pulmonary function tests (PFT's) Examples are given of how the model is capable of simulating a wide variety of physiologic lung disorders allowing the examination of abnormal PET results in terms of regional conditions and how it may be employed as a research tool in simulating altered environmental condition.