Pulmonary Interstitial Mechanics

肺间质是从肺中排出微血管滤液的途径。因此，它的性质对于理解如何维持正常的液体平衡和肺水肿的发病机制是重要的。间质液体的清除依赖于由静水压力差异引起的整体流动和由蛋白质浓度不同引起的渗透流动。在以前的研究中，测量了水合作用、蛋白质浓度、液体粘度、电荷和透明质酸酶对间质电导率的影响。在白蛋白和透明质酸溶液中，白蛋白和透明质酸酶的作用与空间排斥的预期相反。最近的研究表明，白蛋白的间质筛选和有限反射系数在正常水化的低浓度下增加，并伴随着白蛋白的自由扩散。这种膜状性质与通常分配给间质的溶液性质相反。一个主要的目标是用膜的性质来描述间质。将研究透明质酸酶对白蛋白间质筛分的影响，以及水化对透明质酸酶扩散反应减弱的影响。在液体充气肺的间质袖带生长过程中，白蛋白浓度的纵向梯度的研究将支持在稳态流中在间质节段测量的筛分行为。这些研究将测量白蛋白在从小动脉到大血管的血管间质袖带中的空间排斥。

The pulmonary interstitium is a pathway that drains microvascular filtrate from the lung. Thus its properties are important to the understanding how normal fluid balance is maintained and the pathogenesis of pulmonary edema. The clearance of interstitial fluid depends on bulk flow caused by differences in hydrostatic pressure and osmotic flow caused by differences in protein concentration. In previous studies, the effects of hydration, protein concentration, fluid viscosity, electric charge, and hyaluronidase on interstitial conductivity were measured. The effects of albumin and hyaluronidase were opposite to those expected from steric exclusion in solutions of albumin and hyaluronan. Recent studies indicated interstitial sieving of albumin and a finite reflection coefficient that increased at low concentrations with normal hydration, in conjunction with free diffusion of albumin. Such a membrane-like property is opposite to the properties of solutions usually assigned to interstitium. A major goal is to describe the interstitium in terms of its membrane properties. The effect of hyaluronidase on interstitial sieving of albumin and the effect of hydration on the reduced diffusive response to hyaluronidase will be studied. The sieving behavior measured in interstitial segments during steady state flow will be supported by studies of the longitudinal gradient in albumin concentration during interstitial cuff growth in liquid-inflated .lungs. These studies will measure steric exclusion of albumin in interstitial cuffs of vessels ranging from arterioles to large vessels.