Mechanical Aspects of Pulsatile Blood Flow

脉动血流的机械方面

• 批准号: RGPIN-2018-03842
• 负责人: Zamir, Mair
• 金额: $ 2.33万
• 依托单位: University of Western Ontario
• 依托单位国家: 加拿大
• 项目类别: Discovery Grants Program - Individual
• 财政年份: 2018
• 资助国家: 加拿大
• 起止时间: 2018-01-01 至 2019-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=669550
• 关键词: Mechanical; Aspects; Pulsatile; Blood; Flow

Blood is widely considered as the very essence of life, yet, in fact, the essence of life is not blood but blood flow. When the heart stops beating, the body dies not because of lack of blood but because of lack of blood flow. This proposal is about blood flow.*Blood flow within the cardiovascular system is a highly complex dynamical system consisting of a myriad of tubes and tube junctions. The basis of this proposal is that a full understanding of this complex system lies in the realm of Mechanics, not Medicine. ****** There are two aspects of blood flow that reside decidedly in the realm of Mechanics: (1) The pulsatile nature of the flow gives the system a dynamical dimension beyond the common “plumbing” view of blood flow where disruptions in blood flow are seen in terms of only blood vessel occlusions. This is an incomplete view of pulsatile blood flow because it ignores the oscillatory dynamics of the flow. (2) While “flow” as such is controlled by the laws of physics, blood flow within the cardiovascular system is subject also to neurovascular control originating in demands for blood supply from different regions of the body and mediated by control centers in the brain. The way these systems work together is not fully understood and, again, the subject lies fully in the realm of Mechanics.******* The focus of this proposal is on a study of these dynamical aspects of blood flow in three specific organs: the brain, the heart, and the uterus. There are unique mechanical issues that are specific to each, as described briefly below.*In the brain, pulsatile blood flow takes place within the confines of a rigid skull. As a result, the relationship between pressure and flow is different from that elsewhere in the cardiovascular system and is currently not fully known. We are pursuing methodologies that allow a noninvasive study of that relationship, with the aim of establishing a better understanding of the mechanics of cerebral blood flow.*In the heart, perfusion of the heart muscle which does much of pumping action is critical to normal heart function. It is not known how the vasculature of the heart muscle achieves the required continuous and reasonably uniform perfusion at different depths of the heart muscle. We are using a combination of micro-CT imaging and vascular tree tracking techniques to study the fluid dynamic basis of blood supply to the heart muscle.*Blood supply to the uterus combines some of the most complex elements of vascular architecture and vascular control mechanisms in the cardiovascular system. A unique feature of this system is a group of spiral arteries which in the course of normal pregnancy undergo an intricate transformation in their geometry and mechanical properties. To date, the fluid dynamic principles governing the functional design of this system, particularly under pulsatile flow conditions, are not fully understood. A major study of the vascular architecture and control mechanisms involved is part of this proposal.******

血液被广泛认为是生命的本质，但事实上，生命的本质不是血液，而是血流。当心脏停止跳动时，身体死亡不是因为缺乏血液，而是因为缺乏血液流动。这篇文章是关于血液流动的。心血管系统内的血液流动是由无数管和管接头组成的高度复杂的动力学系统。这一建议的基础是，对这个复杂系统的充分理解在于力学领域，而不是医学。** 血流有两个方面明确属于力学领域：（1）血流的脉动性质使系统具有超越常见的血流“管道”视图的动力学维度，在该视图中，血流中的中断仅被视为血管闭塞。这是对脉动血流的不完整的看法，因为它忽略了血流的振荡动力学。(2)虽然“流动”本身由物理定律控制，但心血管系统内的血流也受到神经血管控制，神经血管控制源于对来自身体不同区域的血液供应的需求，并由大脑中的控制中心介导。这些系统协同工作的方式还没有完全理解，同样，这个主题完全属于力学领域。 该建议的重点是研究三个特定器官中血流的动力学方面：大脑，心脏和子宫。每一种机器都有其独特的机械问题，如下所述。*在大脑中，脉动的血液流动发生在刚性头骨的范围内。因此，压力和流量之间的关系与心血管系统中的其他地方不同，目前还不完全清楚。我们正在寻求方法，允许对这种关系进行非侵入性研究，目的是更好地了解脑血流的机制。在心脏中，进行大量泵送动作的心肌灌注对正常心脏功能至关重要。尚不知道心肌的脉管系统如何在心肌的不同深度处实现所需的连续且合理均匀的灌注。我们正在使用显微CT成像和血管树跟踪技术的组合来研究心肌血液供应的流体动力学基础。子宫的血液供应结合了心血管系统中血管结构和血管控制机制的一些最复杂的要素。该系统的一个独特特征是一组螺旋动脉，其在正常妊娠过程中经历其几何形状和机械性质的复杂转变。到目前为止，控制该系统的功能设计的流体动力学原理，特别是在脉动流条件下，还没有完全理解。一项有关血管结构和控制机制的主要研究是这项提议的一部分。