Bar-Yishay E, Hyatt R E, Rodarte J R
J Appl Physiol (1985). 1986 Aug;61(2):712-8. doi: 10.1152/jappl.1986.61.2.712.
In head-up dogs the vertical gradient of transpulmonary pressure (VGTP) disappears after pneumothorax develops. Our laboratory recently confirmed that the heart moves downward and posteriorly with pneumothorax. To study the extent to which the heart is supported by the lungs, we used a linear elasticity model and finite-element analysis. The lung and heart were assumed to be symmetric along a vertical axis. Reported values of the elastic properties of lung and heart were assigned. The model was generated first without the heart, using the lung alone. The heart was then added to the model. Finally, heart weight was doubled. Adding the heart caused the VGTP to increase; doubling the heart weight further increased the VGTP. These increases were more pronounced at higher lung volumes. Lung inflation was accompanied by an upward displacement of the heart. Inclusion of the heart caused increased inhomogeneities in regional volume distribution. The effect of heart weight may in part explain why the VGTP in the head-up dog is greater than that predicted by lung density.
在头高位的犬中，气胸发生后跨肺压的垂直梯度（VGTP）消失。我们实验室最近证实，气胸时心脏会向下和向后移动。为了研究心脏受肺支撑的程度，我们使用了线性弹性模型和有限元分析。假设肺和心脏沿垂直轴对称。赋予了报道的肺和心脏弹性特性值。首先在没有心脏的情况下仅使用肺生成模型。然后将心脏添加到模型中。最后，将心脏重量加倍。添加心脏导致VGTP增加；将心脏重量加倍进一步增加了VGTP。这些增加在较高肺容积时更为明显。肺充气伴随着心脏向上移位。包含心脏导致区域容积分布的不均匀性增加。心脏重量的影响可能部分解释了为什么头高位犬的VGTP大于根据肺密度预测的值。
