胸部撞击时胸壁的动力学响应及心脏损伤

Cardiac injury and dynamic responses of the thoracic wall during thoracic impact in rabbits *

目的：探讨不同撞击条件下胸壁的动力学响应过程、心脏病理改变和心律失常的发生特点及可能机制，分析胸壁的粘弹性运动过程及其与伤情间的关系。方法：用ＢＩＭ－Ⅱ型生物撞击机，以准静态和动态撞击方式进行兔胸部正、侧向撞击致伤，观察心脏损伤的病理特点和心律失常的发生情况，分析致伤物理参数和胸壁动力学响应与伤情间的量效关系。结果：粘性标准相同时，准静态正向胸部撞击时心脏损伤最重，其次是动态正向撞击组，准静态侧向和动态侧向撞击时心脏伤情较轻。心脏病理改变表现为心内膜下出血、心肌挫伤、心肌纤维断裂。心电图改变表现为窦性心动过缓、异位性早搏、室性节律、室颤等，心律失常的发生可能与压缩幅度相关。结论：心脏损伤与胸部撞击的粘性标准密切相关，心脏损伤机制与心脏侧壁发生高速、过度变形有关。

Objective: To explore the dynamic responses of the thoracic wall, the pathological characteristics of the heart injury, arrhythmia during thoracic impact of various patterns and their possible mechanisms and analyze the relationship between the viscous movement of the thoracic wall and injurious severity. Methods: Using type BIM II impact machine, rabbits were injured by front and lateral impact of static and movable patterns. The characteristics of the heart injury and occurrence of arrhythmia were observed and the relationship between injurious severity and impact parameters and dynamic responses was analyzed. Results: Under the same viscous criterion, the heart injury caused by static front thoracic impact was the most severe, which was followed in order that by static and movable lateral impact and that by movable front impact. The heart usually presented miliary, small spots or striped hemorrhage in the endocardium. Under optical microscope, the interstitial hemorrhage and rupture of the myocardial fibers were seen. The changes of ECG included sinus bradycardia, multiple origin premature beat, ventricular rhythm and ventricular fibrillation. Conclusion: The severity of heart injury was closely correlated with viscous criterion. The heart injury caused by static front thoracic impact was the most severe and rate of arrhythmia more frequent. The injury under movable and lateral impact was mild.