Yen R T, Fung Y C, Ho H H, Buttermann G R
J Appl Physiol (1985). 1986 Aug;61(2):701-5. doi: 10.1152/jappl.1986.61.2.701.
The speed of stress waves in the lung parenchyma was investigated to understand why, among all internal organs, the lung is the most easily injured when an animal is subjected to an impact loading. The speed of the sound is much less in the lung than that in other organs. To analyze the dynamic response of the lung to impact loading, it is necessary to know the speed of internal wave propagation. Excised lungs of the rabbit and the goat were impacted with water jet at dynamic pressure in the range of 7-35 kPa (1-5 psi) and surface velocity of 1-15 m/s. The stress wave was measured by pressure transducer. The distance between the point of impact and the sensor at another point on the far side of the lung and the transit time of the stress wave were measured. The wave speed in the goat lung was found to vary from 31.4 to 64.7 m/s when the transpulmonary pressure Pa-Ppl was varied from 0 to 20 cmH2O where Pa represents airway pressure and Ppl represents pleural pressure. In rabbit lung the wave speed varied from 16.5 to 36.9 m/s when Pa-Ppl was varied from 0 to 16 cmH2O. Using measured values of the bulk modulus, shear modulus, and density of the parenchyma, reasonable agreement between theoretical and experimental wave speeds were obtained.
为了弄清楚为何在所有内部器官中，动物受到冲击载荷时肺是最易受伤的，研究了肺实质中应力波的速度。肺中的声速比其他器官中的声速要低得多。为了分析肺对冲击载荷的动态响应，有必要了解内部波传播的速度。用动态压力在7 - 35 kPa（1 - 5 psi）范围内且表面速度为1 - 15 m/s的水射流冲击切除的兔肺和山羊肺。用压力传感器测量应力波。测量冲击点与肺另一侧另一点处传感器之间的距离以及应力波的传播时间。当跨肺压Pa - Ppl从0变化到20 cmH₂O（其中Pa表示气道压力，Ppl表示胸膜压力）时，发现山羊肺中的波速在31.4至64.7 m/s之间变化。当Pa - Ppl从0变化到16 cmH₂O时，兔肺中的波速在16.5至36.9 m/s之间变化。利用所测得的肺实质的体积模量、剪切模量和密度值，理论波速与实验波速之间获得了合理的一致性。
