Analysis of oxygen diffusion from arteriolar networks.

A mathematical model of oxygen transport in the precapillary microcirculation is presented. The theory is then used to simulate oxygen distribution in the arteriolar network of the hamster cheek pouch. Theoretical prediction of transmural and longitudinal oxygen tension (PO2) gradients is in qualitative agreement with available experimental data. The effect of the variation of inlet network PO2, blood flow rate, blood hematocrit, and other parameters on the transport characteristics is studied. The calculations predict that the luminal PO2 in small arterioles is practically independent of the inlet network PO2 leve if the latter is sufficiently high; when this inlet PO2 level is low, then the longitudinal gradients of luminal PO2 vanish. It is further shown that retardation of blood flow may cause a significant increase in precapillary oxygen losses.