Liang J, Lai-Fook S J
Center for Biomedical Engineering, Wenner-Gren Research Laboratory, University of Kentucky, Lexington 40506-0070, USA.
Respir Physiol. 1996 Dec;106(3):293-305. doi: 10.1016/s0034-5687(96)00083-7.
Degassed rabbit lungs were inflated to 15 cmH2O pressure with 3% albumin solution. To study cuff growth, lungs were frozen in liquid N2 at several (20-120 min) inflation times. Cuff-to-vessel area ratio measured from frozen lung pieces increased with time reaching a maximum value (0.5-0.9) by 1 h. Time constants (to) of cuff growth were similar to those (28 min) of the interstitial pressure (Pi) response measured by micropuncture at the lung hilum. Pi response was slower with saline (to = 84 min) than with albumin. Compared to saline, positively charged protamine sulphate increased the Pi response (to = 44 min). Time constants for cuff growth and Pi response were smaller at 15 cmH2O than at 5 cmH2O inflation pressure (30 vs. 60-120 min). Electrical analog models indicated a doubling of interstitial resistance with a four-to eight-fold decrease in interstitial specific compliance at the higher inflation pressure, the latter attributed to nonlinear elastic behavior of lung parenchyma.
将脱气的兔肺用3%白蛋白溶液充气至15 cmH₂O压力。为了研究袖带生长情况，在几个（20 - 120分钟）充气时间点将肺置于液氮中冷冻。从冷冻的肺组织切片测量的袖带与血管面积比随时间增加，1小时时达到最大值（0.5 - 0.9）。袖带生长的时间常数（τ₀）与通过肺门微穿刺测量的间质压力（Pi）反应的时间常数（28分钟）相似。用盐水时Pi反应较慢（τ₀ = 84分钟），而用白蛋白时较快。与盐水相比，带正电荷的硫酸鱼精蛋白增加了Pi反应（τ₀ = 44分钟）。在15 cmH₂O充气压力下，袖带生长和Pi反应的时间常数比在5 cmH₂O充气压力下小（30分钟对60 - 120分钟）。电学模拟模型表明，在较高的充气压力下，间质阻力增加一倍，间质比顺应性降低四至八倍，后者归因于肺实质的非线性弹性行为。
