PLEURAL LIQUID EXCHANGE AND LUNG MECHANICS

本研究的目的是研究一些机械因素 影响胸膜液体交换的正常生理学， 与肺静态回缩的关系。 经典研究假设， 胸膜液体压力小于胸膜表面压力（肺静态 回缩）且胸膜液处于流体静力平衡（1cm H2O/cm 高度）。 胸膜液负压越大， 由于吸收机制，减少了胸膜液， 胸膜表面接触。 我们将重新审视这些假设 使用新技术。 我们开发了两种相对无创的技术 用于测量胸膜液体压力：微量移液器伺服， 肋骨包膜技术。 对兔子和狗的测量表明， 胸水压力不是静态平衡，而是呈垂直分布 梯度小于lcmH 20/cm。 胸膜液厚度的测量 通过一种新的方法，使用光学显微镜显示两者之间没有接触， 胸膜。 我们将使用这些技术来探索 胸膜液体压力、胸膜液体厚度和肺高度。 第一、 我们将通过微穿刺测量胸膜液的垂直梯度 压力在俯卧和仰卧的狗。 其次，我们将比较胸膜 液压在叶缘和脑表面上， 海岸表面的压力 我们还将测量胸膜 光镜下裂隙厚度。 第三，我们发现， 用光学显微镜测量5种动物胸膜腔厚度 随着动物体型的增加而增加。 我们将把这些测量扩展到更大的 种，羊。 第四，我们将通过伽马相机测量胸膜 液体厚度和胸膜液体的动力学。 我们的研究结果表明 胸腔积液的动力学很重要 最近，我们提出了一个 胸膜液体交换理论，包括 胸膜间隙 胸膜液体交换受液体定律支配 和溶质交换穿过微血管屏障。 粘性流是 由胸膜表面压力和重力的区域差异驱动。 胸膜液体压力等于表面压力。 在稳定状态下， 交换率等于粘性流，粘性流是胸膜的函数， 间隔厚度。 为了验证我们的假设，我们将测量胸腔积液 胸膜厚度、微血管压和胸膜液蛋白浓度 在自发性高血压大鼠（SHR）和对照正常血压大鼠中 （WKY）。 血压升高应增加血流， 降低蛋白质浓度。

The goal of this research is to study some of the mechanical factors affecting the normal physiology of pleural liquid exchange and their relationship to lung static recoil. Classical studies have postulated that pleural liquid pressure is less than pleural surface pressure (lung static recoil) and that pleural liquid is in hydrostatic equilibrium (1 cm H20/cm height). The more negative pleural liquid pressure is presumed to be the result of an absorptive mechanism which reduced the pleural liquid until the pleural surfaces make contact. We will re-examine these postulates using new techniques. We developed two relatively noninvasive techniques for measureing pleural liquid pressure: the micropipet-servonulling and the rib capsule techniques. Measurement in rabbits and dogs indicate that pleural liquid pressure is not in static equilibrium but show a vertical gradient of less than 1 cmH20/cm. Measurements of pleural liquid thickness by a new method using light microscopy show no contact between the two pleurae. We shall use these techniques to explore the relationship between pleural liquid pressure, pleural liquid thickness and lung height. First, we shall measure by micropuncture the vertical gradient in pleural liquid pressure in the prone and supine dog. Second, we shall compare pleural liquid pressure in the lobar margins and on the diaphragmatic surface with the pressure over the costal surface. Also we shall measure pleural thickness at the fissure by light microscopy. Third, we found that the pleural space thickness measured using light microscopy in 5 species increased with animal size. We will extend these measurements to a larger species, the sheep. Fourth, we will measure by a gamma camera the pleural liquid thickness and the dynamics of pleural liquid. Our results suggest that the dynamics of pleural liquid is important. Recently, we proposed a theory of pleural liquid exchange which includes viscous flow within the pleural space. Pleural liquid exchange is governed by the laws of liquid and solute exchange across the microvasclar barrier. The viscous flow is driven by regional differences in pleural surface pressure and gravity. Pleural liquid pressure equals surface pressure. In the steady state the exchange rate equals the viscous flow which is a funciton of the pleural space thickness. To test our hypothesis, we will measure pleural liquid thickness, microvascular pressure and pleural liquid protein concentration in spontaneously hypertensive rats (SHR) and control normotensive rats (WKY). Elevation in blood pressure should increase flow, increase thickness, and decrease protein concentration.