不同肺通气条件下一氧化氮对肺血管调控作用的仿真研究

目的 研究通气量变化时动脉-毛细血管-静脉血管中一氧化氮(nitric oxide, NO)浓度的变化情况以及NO对血管的动态调控机理。方法 应用多物理场耦合分析软件COMSOL Multiphysics建立肺血管网络模型，引入NO对血管的动态调控机制，开展流场-物质浓度场耦合仿真，探究氧气与血流对肺血管网络中NO浓度及其分布的影响，以及通气不足情况下NO对肺血管的动态调节功能。结果 氧浓度及血流会共同影响NO在肺血管网络中的分布。当肺通气不足时，进入肺部毛细血管的氧气量降低。静态条件下，肺静脉血管壁NO浓度明显降低；动态条件下，NO浓度降低会导致血管收缩，血管半径下降，使得NO浓度降低得到动态补偿。血管紧张度调控系数α直接影响NO的调控作用，α在一定范围内起作用，其值越高血管半径的变化越大，NO浓度变化越小，且α的有效取值范围大于1。结论 研究结果揭示了通气量变化时动脉-毛细血管-静脉血管中NO浓度的变化情况以及NO对血管的动态调控机理，并预测α的有效取值范围，为进一步研究通气不足情况下由于血管收缩而使血管阻力发生变化进而影响血流量、调控通气灌注比的机制提供理论依据。
Objective To study the changes of nitric oxide (NO) concentration in arterial-capillary-venous vessels and the dynamic regulation mechanism of NO on the vessels during ventilation changes. Method The pulmonary vascular network model was established by using the COMSOL Multiphysics software, the dynamic regulation of NO on blood vessels was introduced, the flow-multiphysics coupling simulation was conducted to explore the effect of oxygen and blood flow on NO concentration and its distribution in pulmonary vascular network, and the dynamic regulation of NO on pulmonary vascular function in the case of ventilation lacking. Results Oxygen concentration and blood flow would jointly affect the NO distribution in the pulmonary vascular network. When lung ventilation was insufficient, the amount of oxygen entering the pulmonary capillaries decreased, and the NO concentration in pulmonary vein walls under static conditions was significantly reduced. The reduction of NO concentration under dynamic conditions led to vasoconstriction and decrease of blood vessel radius, resulting a dynamic compensation. Regulation of vascular tension regulation coefficient α would directly affect the regulation of NO. When α worked within a certain range, a higher value of α meant a larger change in vascular radius and a smaller change in NO concentration, and its effective value was greater than 1. Conclusions The research findings revealed the change of NO concentration in arterial-capillary-venous vessels due to the change of ventilation as well as the dynamic regulation mechanism of NO in blood vessels, and predicted the effective value range of α，thus providing theoretical basis for further research on the mechanism of blood flow, ventilation perfusion ratio affected by vasoconstriction and vascular resistance changes due to ventilation insufficiency.