Dodek P M, Rice T W, Bonsignore M R, Yamada S, Staub N C
Circ Res. 1986 Feb;58(2):269-80. doi: 10.1161/01.res.58.2.269.
The Starling equation, which describes net transvascular liquid flow, does not include the possibility that a reduction in plasma protein concentration may have a direct effect on lung liquid conductance or microvascular protein permeability. Nevertheless, both effects have been reported. Since these results were not predictable, we wondered whether the changes were due to the decrease in plasma protein concentration or to the process by which protein depletion was accomplished (batch plasmapheresis which involves considerable handling of blood). To separate these factors, we did control (sham) and protein removal plasmapheresis in awake sheep by two plasmapheresis methods (batch and continuous-flow). We monitored pulmonary hemodynamics, measured lung lymph flow, and determined protein concentrations in lymph and plasma. We calculated or measured the protein osmotic pressures of plasma and lymph. After control plasmapheresis, lymph flow increased and lymph:plasma protein concentration decreased but had returned to baseline levels by 4 hours. After protein removal plasmapheresis, the changes persisted for 24 hours. However, lung microvascular conductance (filtration coefficient) was not increased, except during the first 4-hour period. The changes in lymph flow and protein concentration ratio are explained using a simple two-pore model. We conclude that, over the range studied, hypoproteinemia does not increase lung microvascular liquid conductance or protein permeability.
描述跨血管液体净流量的斯塔林方程并未考虑血浆蛋白浓度降低可能对肺液体传导率或微血管蛋白通透性产生直接影响的可能性。然而，这两种影响均有相关报道。由于这些结果无法预测，我们想知道这些变化是由于血浆蛋白浓度降低所致，还是由于实现蛋白耗竭的过程（涉及大量血液处理的批量血浆置换）所致。为了区分这些因素，我们通过两种血浆置换方法（批量和连续流动）对清醒绵羊进行了对照（假手术）血浆置换和去除蛋白的血浆置换。我们监测了肺血流动力学，测量了肺淋巴流量，并测定了淋巴和血浆中的蛋白浓度。我们计算或测量了血浆和淋巴的蛋白渗透压。对照血浆置换后，淋巴流量增加，淋巴与血浆蛋白浓度比值降低，但4小时后恢复到基线水平。去除蛋白的血浆置换后，这些变化持续了24小时。然而，肺微血管传导率（滤过系数）并未增加，除了在最初的4小时内。使用一个简单的双孔模型解释了淋巴流量和蛋白浓度比值的变化。我们得出结论，在所研究的范围内，低蛋白血症不会增加肺微血管液体传导率或蛋白通透性。
