短时激波作用下家兔胸腹内压力的变化

Pressure Changes in Thoracic and Abdominal Cavities after Brief Exposure to Blast Waves in Rabbits

在短时激波作用下,机体胸腹腔之间存在着压力差,但缺乏实验证据。本实验通过引爆200g TNT炸药块致伤家兔,观察距爆心1.6m、1.8m和2.0m处爆炸激波作用下的家兔胸腹内压同步变化情况。动物致伤后立即解剖,观察动物伤情。实验结果显示,胸内正、负压峰值明显大于腹内正、负压峰值,而且压力的变化存在着时相上的差异,从胸腹内压峰值和时相变化上证实胸腹间存在着压力差,家兔胸腹腔之间的压力呈双向传导。实验结果提示家兔胸腹腔内器官组织冲击伤的发生可能与体腔扩张引起的负压增高有关,本文就肺冲击伤发生机理从压力差角度加以讨论。

This study was performed in an attempt to clarify whether there really exists a pressure difference between the thoracic and abdominal cavities when the body is exposed to blast waves of short duration. When 20 rabbits were exposed to a 200 g TNT explosion at a distance of 1.6, 1.8, and 2 metere respectively, 3 piezo-resistance transducers were placed on the body surface, in the esophagus, and in the upper abdominal cavity of each animal to measure the reflected pressure (Pe) against the body, the pressure in the thoracic cavity (Pt) and that in the abdominal cavity (Pa). All the rabbits were killed and dissected after exposure to blast waves. It was found that the peak value of both overpressure and negative pressure of Pt was significantly higher than those of Pa, and the pressure changes varied with the time course after exposure. Pt and Pa were cnoducted in double directions. Our findings confirm that pressure difference does exist between the thorax and abdomen. The mechanism of the genesis of lung blast injury was discussed on the point of pressure changes, and it is believed that the blast injury on the viscera of the thoracic and abdominal cavities is likely precipitated by the sudden increase of negative pressure created by the expansion of cavity walls.