NEW METHODOLOGIES FOR THE DESIGN OF SMALL BLOOD PUMPS

描述（由申请人提供）：本研究的目的是为体型较小的成人患者提供搏动心脏替代系统。这是一件非常重要的事情，因为脉动式血泵尺寸的减小会影响(1)泵的流体动力学，(2)泵和致动器的能量学，以及(3)血液接触材料所经历的应力。因此，我们认为这些研究对于为所有患者提供人工心脏和搏动性心室辅助装置至关重要。我们建议通过三个具体目标来研究泵尺寸减小的基本原理：第一，利用CFD建模、实验流体动力学技术、体外测试和体内研究的综合方法，利用物理设计约束显著改进缩小尺寸的血泵和能量转换器设计。这些建模和体外研究将用于预测系统性能。这些发现的意义将通过对小牛的体内研究进行评估。血栓形成将通过血液学研究，血小板活化研究和外植体分析进行评估。血小板和纤维蛋白粘附将通过外植体后大体检查、组织学检查和多尺度表面分析来量化。其次，我们利用计算机模拟能量转换器、血泵、循环、控制器和能量传输系统，建立了控制系统能量性能的关系。我们将调整执行器运动的控制，以改进流体力学。这些研究的结果也将在体外和体内进行评估。第三，我们将完善和利用改进的有限元模型来预测和最小化生物材料中的应力，这样缩小尺寸的设备的耐久性就不会受到泵缩放的不利影响。我们期望这项研究将广泛适用于脉动血泵的设计，特别是通过提高我们对复杂时变流场中表面效应、流体动力学和血栓形成之间关系的理解。这项工作需要在外科、工程、流体力学和血液学等多学科的努力下，有效地制造血泵系统，并进行必要的体外和体内研究。

DESCRIPTION (provided by applicant): The objective of this research is to make pulsatile heart replacement systems available to smaller adult patients. This is a non-trivial matter, because reduction in the size of a pulsatile blood pump affects (1) the fluid dynamics of the pump, (2) the energetics of the pump and actuator, and (3) the stresses experienced by the blood contacting materials. Thus, we consider studies such as those described here to be critical to the availability of artificial hearts and pulsatile ventricular assist devices for the full spectrum of patients. We propose to study the underlying principles of pump size reduction through three specific aims: FIRST, Utilize an integrated method of CFD modeling, experimental fluid dynamics techniques, in vitro testing and in vivo studies to significantly improve reduced size blood pumps and energy converter designs utilizing physical design constraints. These modeling and in-vitro studies will be used to predict system performance. The significance of these findings will be assessed through in vivo studies in calves. Thrombogenesis will be assessed through hematology studies, platelet activation studies, and explant analysis. Platelet and fibrin adhesion will be quantified by post explant gross exam, histological examination and multi-scale surface analysis. SECONDLY, we have developed relationships governing energetic performance of the system, utilizing a computer simulation of the energy converter, blood pump, circulation, controller, and energy transmission system. We will tailor control of actuator movement to improve fluid mechanics. The results of these studies will also be evaluated in-vitro and in-vivo. THIRDLY, we will refine and utilize improved FEA models necessary for predicting and minimizing stresses in biomaterials, so that durability of reduced-size devices is not adversely affected by pump scaling. We expect that this research will be broadly applicable to pulsatile blood pump design, especially by improving our understanding of the relationships between surface effects, fluid dynamics, and thrombogenesis in a complex, time-varying flow field. This work requires a multi-disciplinary effort in surgery, engineering, fluid mechanics, and hematology, with the means to efficiently manufacture blood pump systems and carry out the necessary in vitro and in vivo studies. PUBLIC HEALTH RELEVANCE: This research combines computational fluid dynamics, experimental fluid dynamics, systems modeling, finite element analysis, in vitro and in vivo techniques to develop a comprehensive method for the design of small blood pumps.