模拟循环系统中的主动脉流间接测量

模拟循环系统主动脉内的流量波动很大,采用流量计直接测量受管道直径、管壁厚度、流量计量程等因素制约，不利于对不同研究对象进行模拟.文中提出一种利用压力信号间接测量主动脉流的方法.首先利用不同的Windkessel模型对模拟体循环系统进行建模，然后分别以主动脉压和动脉压作为输入变量和观测变量，利用扩展卡尔曼滤波器对模型参数和主动脉流进行联合估计.流量的估计精度采用均方根误差指标进行评估.结果表明，四元Windkessel模型可以很好地描述系统的动态性能并估计流量，为心血管装置的定量分析和测试提供了新的方法.

Indirectly Measuring Aortic Flow in a Mock Circulatory System

In mock circulatory systems, the aortic flow is of violent pulsation. Measuring this signal directly with flow meter will limit its applications to mimic different physiological objects, considering the effects of diameter and wall thickness of the tube, the measurement range of flow meters, etc. In order to solve these problems, an indirect method using pressure signal to estimate the pulsatile flow was proposed. The mock circulatory system is first modeled with different Windkessel models. Then the aortic pressure and arterial pressure are considered as the input and observation variable, respectively, to estimate model parameters and aortic flow based on the extended Kalman filter (EKF). The accuracy of flow estimation is evaluated by the root mean square error index. The experimental results show that the four element Windkessel model can describe the dynamic performance of the mock circulation system and thus estimate the aortic flow. This paper provides a novel method to measure the aortic flow in testing and evaluating cardiovascular devices. Key words：