Bidani A, Crandall E D, Forster R E
J Appl Physiol Respir Environ Exerc Physiol. 1978 May;44(5):770-81. doi: 10.1152/jappl.1978.44.5.770.
A quantitative description of the reaction and transport processes that take place in blood during and after gas exchange in capillaries is developed and used to interpret recently reported experimental results. Included in the computation are 1) CO2-H2CO3 hydration-dehydration reactions in plasma and erythrocytes, 2) CO2 reactions with hemoglobin, 3) O2 binding to hemoglobin, 4) buffering of H+ intra- and extracellularly, 5) HCO3- Cl- exchange across the red cell membrane, 6) diffusion of gases between alveolar gas and blood, and 7) transcellular movement of water. Ion and water fluxes are described assuming passive diffusion down their electrochemical potential gradients. Recent data on the magnitude of the Bohr and Haldane shifts and on carbamate formation in the presence of 2,3-diphosphoglycerate are used. The analysis is used to examine the direction, magnitude, and time course of plasma pH changes in blood leaving the pulmonary capillaries and is shown to preduct results that agree very closely with recently reported experimental measurements in vivo. The time computed for plasma pH equilibration after gas exchange when carbonic anhydrase activity is absent from plasma is so great that blood may never be in complete electrochemical equilibrium as it travels around the circulation in normal man.
本文建立了一种对毛细血管气体交换过程中及之后血液中发生的反应和传输过程的定量描述，并用于解释最近报道的实验结果。计算中包括：1）血浆和红细胞中的CO2 - H2CO3水合 - 脱水反应；2）CO2与血红蛋白的反应；3）O2与血红蛋白的结合；4）细胞内和细胞外H +的缓冲作用；5）HCO3 - Cl -跨红细胞膜的交换；6）肺泡气与血液之间气体的扩散；7）水的跨细胞运动。离子和水通量通过假设沿其电化学势梯度的被动扩散来描述。本文使用了关于波尔效应和哈勒丹效应大小以及在2,3 - 二磷酸甘油酸存在下氨基甲酸盐形成的最新数据。该分析用于研究离开肺毛细血管的血液中血浆pH变化的方向、大小和时间进程，并显示出与最近报道的体内实验测量结果非常吻合的预测结果。当血浆中不存在碳酸酐酶活性时，计算出的气体交换后血浆pH平衡时间非常长，以至于在正常人体内血液在循环过程中可能永远不会处于完全的电化学平衡状态。
