Local plasma convection can be important for oxygen release in tissue capillaries

Aroesty and Gross investigated the effect of mixing in gaps between two successive RBCs on the local mass transfer at the capillary wall. They found that the effect was insignificant. In this presentation it is shown that their conclusion results from their choice of boundary conditions. When boundary concentrations are chosen which are more similar to those in diffusional models the flux at the capillary wall increases significantly when mixing increases. The calculations presented indicate that mixing of plasma may enhance oxygen transport, although it is impossible to assess the physiological importance. To be able to investigate that, a model has to be developed that includes oxygen transport in both the RBCs and tissue, the oxygen release in the RBCs, and the oxygen consumption in the tissue.