Performance prediction of a percutaneous ventricular assist system using nonlinear circuit analysis techniques.
Performance prediction of a percutaneous ventricular assist system using nonlinear circuit analysis techniques.
复制标题
使用非线性电路分析技术预测经皮心室辅助系统的性能。
DOI：
10.1109/tbme.2007.908092
复制
发表时间：
2008
期刊：
影响因子：
--
通讯作者：
Zorn,NicholasV
中科院分区：
文献类型：
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作者：
Yu,Yih-Choung;Simaan,MarwanA;Mushi,SimonE;Zorn,NicholasV
经皮心室辅助装置（pVAD）是一种体外心脏辅助系统，通过血泵将血液从静脉循环分流到动脉循环，支持晚期心力衰竭患者衰竭的心室。该系统可以使用标准的介入技术植入导管实验室，通常由静脉或心房引流套管、VAD（或血泵）和动脉灌注套管组成。由于该设备允许临床医生根据患者的体型和动脉的大小自由选择导管的配置和大小，因此在植入该设备以支持患者之前，能够预测该设备可以提供的血流量是极其困难但重要的。在本文中，我们开发了一种新的方法，该方法可以根据动脉导管的大小和配置、泵速以及患者的左心房和平均动脉压来准确预测该装置可以提供给患者的平均流速。为此，我们首先建立了pVAD的非线性电路模型。该模型包括一个速度相关的电压源和流量相关的电阻，以模拟设备中各种套管中的压力-流量关系。我们表明，通过该装置的流量可以通过求解一个二次方程来确定，该方程的系数根据动脉插管的大小和配置进行缩放。该模型和预测方法在TandemHeart pVAD （Cardiacassist, Inc., Pittsburgh， PA）支持的测试回路上进行了实验测试。通过与实验数据的比较，我们的方法可以准确地预测流量，在整个设备预期使用范围内的所有测试条件下，误差指数小于6%。对pVAD模型与心血管模型耦合的计算机模拟表明，无论心血管系统引入的脉动性如何，该方法在设备正常工作范围内估计平均流量的准确性是一致的。这种方法可以作为辅助心脏病专家为pVAD患者选择合适的动脉插管配置和大小的附加方法。也可作为培训临床人员在不同生理条件下操作设备的工具。
A percutaneous ventricular assist device (pVAD) is an extracorporeal cardiac assist system that supports the failing ventricle in advanced stage heart failure by bypassing blood from the venous to the arterial circulation through a blood pump. The system can be implanted in a Cath lab using standard interventional techniques, and typically consists of a venous or atrial drainage cannula, the VAD (or blood pump), and an arterial perfusion cannula. Because the device allows clinicians the freedom of choosing the configuration and size of the cannulae based on the patient's body size and the size of the artery, it is extremely difficult but important to be able to predict the amount of blood flow that the device can provide before it is implanted to support the patient. In this paper, we develop a novel method that can be used to accurately predict the mean flow rate that the device can provide to the patient based on the size and configuration of the arterial cannula, the pump speed, and the patient's left atrial and mean arterial pressures. To do this, we first develop a nonlinear electric circuit model for the pVAD. This model includes a speed dependent voltage source and flow dependent resistors to simulate the pressure-flow relationship in the various cannulae in the device. We show that the flow rate through the device can be determined by solving a quadratic equation whose coefficients are scaled depending on the size and configuration of the arterial cannula. The model and prediction method were tested experimentally on a test loop supported by the TandemHeart pVAD (Cardiacassist, Inc., Pittsburgh, PA). A comparison of the predicted flow rates obtained from our method with experimental data shows that our method can predict the flow rates accurately with error indices less than 6% for all test conditions over the entire range of intended use of the device. Computer simulations of the pVAD model coupled to a cardiovascular model showed that the accuracy of the method in estimating the mean flow rate is consistent over the normal range of operation of the device regardless of the pulsatility introduced by the cardiovascular system. This method can be used as an additional too to assist cardiologists in choosing a proper arterial cannulae configurations and sizes for pVAD patients. It can also be used as a tool to train clinical personnel to operate the device under different physiological conditions.