DYNAMICS OF CAPILLARY FLUID EXCHANGE - NON-LINEAR COMPUTER-SIMULATION

A nonlinear computer simulation program has been employed to analyze capillary fluid balance during a variety of perturbations, such as changes in arterial or venous pressures, plasma oncotic pressure, interstitial mucopolysaccharide content, and lymphatic obstruction. The results indicate that normally tissue colloid osmotic pressures of 9.3 mm Hg are required for an equilibrium of filtration and reabsorption, equivalent to an interstitial plasma protein concentration of 3.4%. Dilution of this extravascular protein pool forms a first line of defense against edema formation. Washout of interstitial protein during hypoproteinemia may serve as an effective form of autotransfusion. Simulation of five different types of edema revealed significant differences in interstitial fluid distribution and protein content. Comparison of the simulation program with a large number of physiological and clinical studies yielded good agreement, supporting the validity of the simulation program. © 1979.