NEW METHODOLOGIES FOR THE DESIGN OF SMALL BLOOD PUMPS

描述（由申请人提供）： 这项研究的长期目标是使脉动心脏置换系统可用于较小的成年患者。这是一个重要的问题，因为脉动血泵尺寸的减小影响（1）泵的流体动力学，（2）泵和致动器的能量学，以及（3）血液接触材料所经受的应力。因此，我们认为这些研究是至关重要的人工心脏和脉动心室辅助装置的成人患者的全谱的可用性。我们建议通过以下三个具体目标来研究减小泵尺寸的基本原则： 首先，我们将比较体外测量的流场与体内测量的血栓形成和溶血。具体来说，我们将使用计算流体动力学预测流场和激光多普勒测速和粒子图像测速测量流体速度和剪切速率与高度的空间和时间分辨率，在泵室设计根据各种缩放参数。经典的无量纲分析将作为缩放的指导，以实现流体动力学相似，并概括这些测量的预测目的。将通过使用完全植入血泵的小牛体内研究，在相似的流体动力学条件下使用相同的泵腔，评估这些发现的意义。将通过血液学研究和取出物分析评估血栓形成。将使用取出后大体检查、组织学检查和多尺度表面分析来量化血小板和纤维蛋白粘附。快速制造方法将用于制造这些实验所需的各种泵室。第二，我们将利用能量转换器、血泵、循环、控制器和能量传输系统的计算机模拟，开发控制系统能量性能的关系。因此，我们将优化主要子系统，以最大限度地减少功耗。将在模拟循环回路上验证结果。 第三，我们将使用有限元分析研究减小泵腔尺寸和泵形状参数对生物材料应力的影响。将使用静压泵室对预测的应变进行验证。我们希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的理解之间的关系的流体动力学和血栓形成在一个复杂的，随时间变化的流场。这项工作需要外科、工程学、流体力学和血液学等多学科的努力，同时需要有效制造血泵系统并进行必要的体外和体内研究。

DESCRIPTION (provided by applicant): The long-term 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 adult patients. We propose to study the underlying principles of pump size reduction through three specific aims: FIRST, we will compare in vitro measurements of the flow field with in vivo measures of thrombogenesis and hemolysis. Specifically, we will use Computational Fluid Dynamics to predict the flow field and Laser Doppler Anemometry and Particle Image Velocimetry to measure fluid velocity and shear rate with a high degree of spatial and temporal resolution, in pump chambers designed according to various scaling parameters. Classical dimensionless analysis will serve as guidance in scaling to achieve fluid dynamic similitude, and to generalize these measurements for predictive purposes. The significance of these findings will be assessed through in vivo studies in calves using completely implanted blood pumps, using the same pump chambers under similar fluid dynamic conditions. Thrombogenesis will be assessed through hematology studies and explant analysis. Platelet and fibrin adhesion will be quantified using post explant gross exam, histological examination and multi-scale surface analysis. Rapid manufacturing methods will be used to fabricate the variety of pumping chambers required for these experiments. SECONDLY, we will develop 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 thereby optimize the major subsystems to minimize power consumption. Results will be validated on a mock circulatory loop. THIRDLY, we will study the effects of reduced pump chamber size and pump shape parameters on biomaterial stresses using finite element analysis. Predicted strains will be validated using statically pressurized pump chambers. We expect that this research will be broadly applicable to pulsatile blood pump design, especially by improving our understanding of the relationships between 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 efficiency manufacture blood pump systems and carry out the necessary in vitro and in vivo studies.