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目的仿真研究不同角度倾斜对人体心血管系统血液动力学的影响,并与已发表实验数据比较,以校验所用分布式心血管系统数学模型是否可用于失重对心血管影响的仿真研究,提出存在问题及改进方向。方法利用该模型沿血管方向调整重力分量模拟人体倾斜角度的变化,计算变化过程中人体的心血管响应。结果随倾斜角度绝对值的增加,所有血管的平均血压都近似呈不同方向的指数变化。人体由直立体位转至水平体位,中心静脉压呈指数增加;心率虽呈指数降低,但变化幅度很小;每搏量呈线性增加。静脉系统的流体静压参考点位于右心房和下腔静脉之间。仿真结果与报道的人体倾斜或卧床实验数据相近。结论该模型可以有效地模拟人体倾斜角度变化时心血管系统的急性响应;但为了仿真长期航天失重环境下心血管系统的适应性变化,还需将血量调节,心脏与血管功能和结构的慢性适应变化,以及神经-体液调节等机制耦合进来。
Objective To simulate the effects of tilt at different angles on the hemodynamics of the human cardiovascular system and compare it with published experimental data to verify whether the distributed model of cardiovascular system used is suitable for simulating the effects of weightlessness on cardiovascular outcomes. Problems and improvement direction. Methods The model was used to adjust the gravitational component in the direction of the blood vessel to simulate the change of human tilt angle and calculate the cardiovascular response of the human body during the change. Results With the increase of the absolute value of the tilt angle, the average blood pressure of all the vessels showed similar exponential changes in different directions. The body from the orthostatic position to the level position, the central venous pressure increased exponentially; although the heart rate decreased exponentially, but the rate of change is small; stroke volume increased linearly. The hydrostatic reference point for the venous system is located between the right atrium and the inferior vena cava. The simulation results are similar to the reported body tilt or bed-ridden data. Conclusions This model can simulate the acute response of cardiovascular system effectively when human tilt angle changes. However, in order to simulate the adaptive changes of cardiovascular system under long-term aerospace weightlessness, the model needs to adjust the blood volume, heart and vascular function and structure of chronic adaptation Changes, and neuro-humoral regulation mechanisms coupled.