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飞机在高空飞行中座舱的突然破裂,将导致舱内气压迅速降低,人体肺内气体膨胀和压力骤然增加。这一突然的变化是引起人肺损伤以及其它继发性病理变化甚至死亡的根本原因。故人肺对减压峰值的耐限历来是各国有关学者所关心的问题。我们在大量动物实验(30例活体兔肺、28例活体狗肺静态实验;7例活体狗肺动态实验)和安全线以下的人体实验(4例静态实验,7例动态实验)的基础上,找出了生物体胸肺系统的共同特点:(1)P—V曲线形状相似,数学模型类型一致:(2)模型中C一致,即[V/V_0)_c=常数;(3)P—V曲线C点处的斜率比一致,即(k_0e~(klp))’_C/(k_2l_np+k_2p)’_C=α;(4)生理耐限点D的容积比一致,即(V/V_0]_D=常数。我们由安全范围内人体的实验数据,确定了模型参数k_0、k_1;又根据上述的前三个共同点,从k_0、k_1求解出k_2、k_3,从而确立了人肺的数学模型。通过模型计算,就可获得人肺的破裂强度和生理耐限。静态加压充气条件下.人肺的破裂强度为970mmH_2O,生理耐限为800mmH_2O,安全保险值为650mmH_2O,迅速减压条件下,人肺的破裂强度为1477mmH_2O,生理耐限为1050mmH_2O,安全保险值为860mmH_2O。人体肺胸系统在高载荷下,刚度呈非线性,胸廓效应随着肺容积的扩大而增加。当肺容积扩张到最大容积的86.4％以后,肺组织逐渐变“硬”。肺顺应性明显下降,肺扩张愈来愈难,肺损伤开始加重,这就是肺脏的生理耐限点。
The sudden collapse of the cockpit at high altitude will result in a rapid reduction of the cabin pressure and a sudden increase in gas expansion and pressure in the human lungs. This sudden change is the root cause of human lung injury and other secondary pathological changes and even death. Therefore, the lung resistance to decompression peak has always been the concern of scholars in various countries. Based on a large number of animal experiments (30 live rabbit lungs, 28 live dog lung static experiments; 7 live dog pulmonary dynamic tests) and human subjects below the safety line (4 static experiments and 7 dynamic experiments) (1) P-V curves are similar in shape and the types of math models are the same: (2) C is consistent in the model, ie [V / V_0) _c = constant; (4) The volume ratio of physiological resistance point D is the same, that is, (V / V_0] is the same as the slope ratio at the point C of the V curve, ie, k_0e ~ (klp) _D = constant. We determine the model parameters k_0, k_1 from the human body’s experimental data in the safe range, and then solve k_2, k_3 from k_0, k_1 according to the first three common points, thus establishing the mathematical model of human lung The rupture strength and physiological resistance of human lung can be obtained through the model calculation.Under static pressurization and inflation conditions, the rupture strength of human lung is 970mmH2O, the physiological resistance is 800mmH2O, the safety protection value is 650mmH2O, under the condition of rapid decompression , Human lung rupture strength of 1477mmH_2O, physical resistance of 1050mmH_2O, the safety margin of 860mmH_2O. Human lung and chest system under high load, the stiffness was non Sexual, thoracic effects increase with increasing lung volume. As the lung volume expands to 86.4% of the maximum volume, the lung tissue gradually becomes “hard.” Lung compliance decreases significantly, the lungs become more and more difficult to dilate, and the lung injury begins to aggravate This is the point of physiological resistance of the lungs.