Transient mass transfer processes during the perfusion of a biological organ with a cryophylactic agent solution

An analytical study was performed for the mass transfer processes which occurs during a typical CPA introduction protocol in a biological organ. In such a protocol the concentration of CPA in the perfusate changes linearly with time to a maximal value and is then kept at that value for an additional period of time. Numerical solutions to the Kedem-Katchalsky equations for mass transfer processes in an organ modeled by a large number of typical Krogh tissue units were found. The solutions indicate that several phenomena possibly harmful to the organ occur in the tissue as a function of H, the rate of increase in the CPA concentration.