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目的 仿真头高位倾斜 (HU T)时心血管系统的反应 ,进一步研究有关立位应激的生理机制 .方法 以仿真下体负压 (L BNP)时心血管反应的模型为基础 ,在血液重新分配子模型中引入了重力致血液重新转移的环节 ,在压力反射控制子模型中考虑了心水平与颈动脉压力感受器间的流体静压差 .进行 6名健康男性受试者 30°,45°,6 0°,75°的 HUT试验 ,观察头高位倾斜时血压和心率变化 .结果 仿真结果表明 ,HU T时心率、舒张压和平均压增加 ,心输出量降低 .仿真结果与人体试验结果基本相符 .结论 所建立的模型可用来仿真 HUT时心血管系统反应 ;HUT与 L BNP所涉及的生理机制基本相同 ;本模型为探讨立位应激有关的生理机制提供一个理想的工作模型 .
Objective To study the cardiovascular responses to head-tilt (HU T) and to further investigate the physiological mechanism of standing stress.Methods Based on the model of cardiovascular response simulating lower body negative pressure (L BNP) and redistribution of blood In the sub-model, the gravity-induced redistribution of blood was introduced and the difference of hydrostatic pressure between the cardiac level and the carotid baroreceptor was taken into account in the stress reflex control sub-model. Six healthy male subjects, 30 °, 45 °, HUT test at 6 0 ° and 75 ° to observe the change of blood pressure and heart rate when head tilt was high.Results The simulation results showed that heart rate, diastolic pressure and mean pressure were increased and heart output was decreased at HU T. Simulation results were basically consistent with human test results .Conclusion The established model can be used to simulate the cardiovascular response to HUT. The physiological mechanisms involved in HUT and L BNP are basically the same. This model provides an ideal working model for exploring the physiological mechanism of orthostatic stress.