The effect of oncotic pressure on the equilibrium radius of blood vessels

C. M. Quick, J. K-J. Li, and D. A. O’Hara
3rd Annual Biomedical Engineering Symposium, Piscataway, NJ,  1994

Traditional derivations describing the equilibrium wall tension in a blood vessel assume that the wall consists of a single-phase material. However, the vessel wall consists of solid components and fluid components. These fluid components exert a hydrostatic pressure that affects the equilibrium radius.  Because the hydrostatic pressure of fluid within the wall is a function of oncotic pressure gradients, it is expected that oncotic pressures also affects the vessel's radius. 

In order to study the effect of oncotic pressure gradients on a blood vessel's radius, the vessel wall is treated as a two-phase material. By summing the forces and applying the Starling Hypothesis, a novel equation describing tension in a blood vessel is derived.