STRESS, DEFORMATION, AND ATELECTASIS OF LUNG
STRESS, DEFORMATION, AND ATELECTASIS OF LUNG
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DOI：
10.1161/01.res.37.4.481
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发表时间：
1975-01-01
影响因子：
20.1
通讯作者：
FUNG, YC
中科院分区：
文献类型：
--
作者：
FUNG, YC
肺实质作为一种组织具有相当不寻常的应力-应变关系。提出了这种关系的理论推导，它将肺泡隔膜中的表面张力和组织弹性应力与肺泡几何形状联系起来。数学表达式包含一些有意义的物理常数，可以通过体外和体内实验确定。根据这种应力-应变关系，可以公式化肺力学的一般方程，并提出一些更简单问题的解决方案。首先，分析承受均匀充气压力（定义：肺泡气压-胸膜内压力-胸膜张力X胸膜平均曲率）的肺的平衡，并检查平衡状态相对于小扰动的稳定性。其次，提出了在重力影响下胸部肺部的精确解决方案；当然，该解决方案仅针对特定的肺是“精确的”，但它可以作为检查许多实验室正在开发的数值程序的标准。最后，分析了三种可能的肺不张类型——平面型、轴向型和局灶型。平面型可以存在于正常膨胀的肺中，前提是肺泡层被某种外部因素迫使向平面塌陷。但轴向肺不张（肺泡塌陷成圆柱体）只有在尺寸（肺泡间隔的弹性张力消失）时才会发生。同样，仅当整个肺小于静息容积时才会发生局灶性肺不张。
The lung parenchyma as a tissue has a rather unusual stress-strain relationship. A theoretical derivation of this relationship is presented which connects the surface tension and the tissue elastic stress in the alveolar septa with the alveolar geometry. The mathematical expression contains a few meaningful physical constants which can be determined by in vitro and in vivo experiments. With this stress-strain relationship, the general equations of lung mechanics are formulated, and solutions to some simpler problems are presented. First, the equilibrium of a lung subjected to a uniform inflation pressure (definition: alveolar air pressure - intrapleural pressure - pleural tension X mean curvature of pleura) is analyzed, and the stability of the equilibrium states with respect to small perturbations is examined. Second, an exact solution for a lung in a chest under the influence of gravity is presented; the solution is "exact," of course, for only a particular lung, but it can serve as a standard to check numerical procedures being developed in many laboratories. Finally, three types of possible atelectasis-planar, axial, and focal-are analyzed. The planar type can exist in a normally inflated lung, provided the layers of alveoli are forced to collapse toward a plane by some external agent. But axial atelectasis (alveoli collapse into a cylinder) can occur only if the dimension (at which the elastic tension in the alveolar septa vanishes). Similarly, focal atelectasis can occur only if the entire lung is smaller than the resting volume.