Porous phase model of the lung interstitial fluid motion.

A mathematical model of nonsteady-state fluid movement in the lung interstitium during hydrodynamic loading is evaluated. The model is based on experimental results obtained in isolated perfused canine lungs. The interstitium is treated as a porous phase with an elastic framework, able to relax; all resistance to flux is in the interstitial tissue and not in the endothelium. A numerical iteration procedure was applied for the calculation of fluid transfer coefficients. The model describes space distribution of driving pressures in the interstitium.