Insights on pulsatile flow in the human aorta following sudden deceleration and impact

由于研究车祸后的血液流动和导致钝性创伤性主动脉破裂的机制，本研究项目研究了人体主动脉中不可压缩液体在突然减速和冲击力下的脉动流动。钝性外伤性主动脉破裂定义为主动脉壁横向撕裂或破裂。它是继汽车事故或行人撞击造成的头部受伤之后的第二大死亡原因。它占北美病例的5-16%，每年造成7000至8000人伤亡（每天21人）。它归因于在撞击或高速减速时直接或间接施加于胸部的强烈惯性力的作用。钝性外伤性主动脉破裂过程可能是由解剖和机械因素引起的，并且是多因素的。了解导致钝性外伤性主动脉破裂的机制是一个关键问题；这是一种危及生命的事件，大多数患者（80%至90%）会立即死亡或无法在前往医院的途中存活，因此只有10%至20%的患者能存活下来接受治疗。此外，不幸的是，目前的安全和碰撞保护系统不能显著减少钝性外伤性主动脉破裂。虽然很常见，但导致钝性外伤性主动脉破裂的机制仍未明确确定。本研究计划试图回答的基本问题是：1)在弯曲管道（刚性或弹性）或人体主动脉中流动的流体如何对突然减速和冲击力作出反应；2)由这种冲击产生的能量的耗散所涉及的流动机制是什么，或者流动如何重新组织自己以返回其冲击前的平衡结构。本研究计划包括数值研究和实验研究。回答这些基本问题将有助于更好地理解钝性创伤性主动脉破裂，并帮助汽车行业优化新的安全和碰撞保护系统。

Motivated by the study of blood flow following an automotive accident and the mechanisms leading to blunt traumatic aortic rupture, this research program examines the pulsatile flow of an incompressible fluid in the human aorta subject to a sudden body deceleration and an impact force. Blunt traumatic aortic rupture is defined as a transverse tear or rupture of the aortic wall. It is the second cause of death, after head injury, from automotive accidents or pedestrian impacts. It accounts for 5-16% of cases and in North America and is responsible for 7000 to 8000 casualties per year (21 persons / day). It is attributed to the action of violent inertia forces applied directly or indirectly to the chest at the moment of an impact or high-speed deceleration. Blunt traumatic aortic rupture process is likely to result from both anatomic and mechanical factors and has been shown to be multi-factorial. Understanding the mechanisms leading to blunt traumatic aortic rupture is a crucial issue; it is a life-threatening event and most patients (80% to 90%) will die immediately or will not survive the journey to the hospital, thus, only 10% to 20% survive for medical treatment. Furthermore, current safety and crash protection systems do not allow, unfortunately, a significant reduction in blunt traumatic aortic rupture. Although quite frequent, the mechanisms leading to blunt traumatic aortic rupture are still not clearly identified. The fundamental questions this research program is trying to answer are: 1) how the fluid flow in a curved pipe (rigid or elastic) or human aorta reacts to sudden deceleration and an impact force; 2) what are the flow mechanisms involved in dissipating the energy resulting from this impact or how the flow reorganize itself to return to its pre-impact equilibrium configuration. This research program includes numerical and experimental investigations. Answering these fundamental questions will contribute to a better understanding of blunt traumatic aortic rupture and help automotive industry to optimize new safety and crash protection systems.