Pythoud F, Stergiopulos N, Meister J J
Biomedical Engineering Laboratory, Swiss Federal Institute of Technology, Lausanne, Switzerland.
J Biomech Eng. 1996 Aug;118(3):295-301. doi: 10.1115/1.2796010.
A new separation technique has been developed to determine the forward and backward running arterial pressure wave components. It takes into account friction as well as nonlinear effects due to convective acceleration and to the pressure dependence of the arterial compliance. The new method is a combination of two methods treating friction and nonlinearities separately. The method requires the measurements of pressure and flow at one location as well as the knowledge of the area-pressure relationship. The validity of the method was tested by a simulation experiment in which the forward and backward waves were known a priori. It was shown that the new method is significantly more accurate in the predictions of the forward and backward waves when compared to the classical method assuming linearity and no dissipation. The new wave separation method was also applied to simulated aortic waves for (a) a healthy subject and (b) a subject with decreased compliance. Comparison with the classical linear method showed that neglecting nonlinearities leads to an overestimation of the forward and backward pressure wave amplitudes. The errors, however, were in the order of 5 to 10 percent. We concluded that, for most clinical purposes, the improvement using the nonlinear method is of the same magnitude as experimental errors, and thus the linear method would suffice.
一种新的分离技术已被开发出来，用于确定向前和向后传播的动脉压力波分量。该技术考虑了摩擦以及由于对流加速度和动脉顺应性的压力依赖性所导致的非线性效应。新方法是将分别处理摩擦和非线性的两种方法结合起来。该方法需要测量一个位置处的压力和流量，以及面积 - 压力关系的相关知识。通过一个模拟实验对该方法的有效性进行了测试，在该实验中，向前和向后的波是事先已知的。结果表明，与假设线性且无耗散的经典方法相比，新方法在预测向前和向后的波时显著更准确。新的波分离方法还被应用于模拟的主动脉波，用于（a）健康受试者和（b）顺应性降低的受试者。与经典线性方法的比较表明，忽略非线性会导致向前和向后压力波幅度的高估。然而，误差在5%到10%的量级。我们得出结论，对于大多数临床目的，使用非线性方法所带来的改进与实验误差量级相同，因此线性方法就足够了。
