胸部钝性冲击时刻对心脏损伤的影响

兰凤崇　童芳　陈吉清　李雄

摘   要：為研究与心动周期有关的胸部冲击时刻对钝性心脏损伤的影响，开发并验证了一个精细人体心脏生物力学模型，并针对40例处于不同心动周期的心脏进行胸部冲击仿真. 心脏模型几何来源于医学影像，包含四个心腔、瓣膜以及主动脉、肺动脉等结构. 通过Abaqus中基于面的流体腔方法考虑冲击过程中血液与心脏的流固耦合作用. 心脏的不同状态采用各心腔内压力与瓣膜的激活与否来表征. 仿真结果显示：（1）建立的心脏模型在胸部正面冲击下心内血压曲线在试验范围内，能够正确反应心脏的冲击响应. （2）乘员胸部正面冲击下，左心房的血压峰值为（164.91±17.33） kPa，明显高于右心腔，使二尖瓣损伤风险高于三尖瓣;右心心肌的应力值为（1887.07±168.74） kPa，远大于左心，导致右心更容易发生心肌破裂. （3）心脏处于心室充盈期受到冲击时，心肌应力为（1901.3±150.7） kPa明显高于其他时刻，更容易发生心脏损伤. （4）心腔内的初始血压对碰撞中的峰值血压影响不明显，Pearson相关系数小于0.2;而瓣膜的开闭状态对心肌的损伤风险影响较大. 研究结果有助于进一步理解钝性心脏损伤机理，为车辆安全设计提供基础.

关键词：生物力学;钝性心脏损伤;冲击时刻;心动周期;流固耦合

中图分类号：U467.14                             文献标志码：A

Effect of Blunt Thoracic Impact Timing on Heart Injury

LAN Fengchong，TONG Fang，CHEN Jiqing LI Xiong

（School of Mechanical &Automotive Engineering，South China University of Technology，Guangzhou 510641，China）

Abstract：To explore the effect of thoracic impact timing related with the cardiac cycle on blunt cardiac injury，a biomechanics model of the heart was developed and validated. Simulations of thoracic impact with 40 hearts in different phases of the cardiac cycle were conducted. The geometry of heart model was obtained from medical imaging，including the structures of four heart chambers，heart valves and vessels etc. The fluid-structure interaction between heart and blood was considered by the method of surface-based fluid cavities in Abaqus. The different phrases of hearts were presented by the intracardiac pressure and valve activation. The simulation results show that： （1）the established heart model can present the correct impact response of the heart under thoracic blunt from the curves of intracardiac blood pressure in the testing ranges. （2）When the passenger thoracic was under the blunt，the peak of intracardiac blood pressure in the left atrium was （164.91±17.33） kPa，which was obviously higher than that of the right heart，causing that the mitral valve is more vulnerable than the tricuspid valve; the stress on the right heart was（1887.07±168.74） kPa，which was higher than the left heart，so the heart rupture is more likely to  occur on the right heart. （3）When the heart was impacted during ventricular filling period， the stress on the myocardium was（1901.3±150.7） kPa， which was higher than that during other impact periods. （4）Initial intracardiac pressure provided little effect on peak pressure， and the Pearson correlation coefficient was less than 0.2; while the state of the atrioventricular valves， open or closed， affects the myocardial injury a lot. This study is helpful to further understand the mechanism of blunt heart injury and provide a basis for vehicle safety design.

Key words：biomechanics;blunt heart injury;impact timing;cardiac cycle;fluid-structure interaction

在交通事故中，乘员胸部极易与方向盘、安全气囊及汽车内饰发生碰撞[1]，由此引起的乘员钝性心脏损伤（Blunt cardiac injury， BCI）的死亡率极高[2]. 数据显示，事故导致的心脏钝性损伤患者有6.3%死于……