The effect of arteriolar resistance on perfusion distribution in a model of the pulmonary perfusion

摘要

Simulations of lung perfusion with a model including elasticity and flow resistance of the lung capillaries, viscosity of the blood and chest wall elasticity show a higher perfusion at the bottom of the lungs (dependent part) than at the top (non-dependent part) due to the effect of gravity. The simulated ratio of dependent/non-dependent perfusion was 6.1, which is higher than experimentally determined ratios of 3.0. This paper explores whether inclusion in the model of arteriolar resistance can reduce this ratio, under the restriction that the pressure drop cause by the arterioles and by the capillaries should be about equal to agree with experimental data. Under this restriction, alveolar resistance reduced the ratio to 4.25. This leaves room for other mechanisms, either passive (anatomical) or active (hypoxic vasoconstriction) to further reduce this ratio.