A computational study of the effect of vasomotion on oxygen transport fromcapillary networks

The objective of this study was to investigate the effect of arteriolar vas omotion on oxygen transport from capillary networks. A computational model was used to calculate blood flow and oxygen transport from a simulated netw ork of striated muscle capillaries. For varying tissue oxygen consumption r ates, the importance of the Frequency and amplitude of vasomotion-induced b lood Row oscillations was studied. The effect of myoglobin on oxygen delive ry during vasomotion was also examined. In the absence of myoglobin, it was found that when consumption is high enough to produce regions of hypoxia u nder steady flow conditions, vasomotion-induced flow oscillations can signi ficantly increase tissue oxygenation and decrease oxygen transport heteroge neity. The largest effect was seen for low-frequency, high-amplitude oscill ations (1.5-3 cycles min(-1), 90% of steady-state velocity). By contrast, a t physiological tissue myoglobin concentrations, vasomotion did not improve tissue oxygenation. This unexpected finding is due to the buffering effect of myoglobin, suggesting that in highly aerobic muscles short-term storage of oxygen is more important than the possibility of increasing transport t hrough vasomotion. (C) 2001 Academic Press.