Luttmann A, Mückenhoff K, Loeschcke H H, Plaas-Link A
Pflugers Arch. 1981 Dec;392(2):146-51. doi: 10.1007/BF00581263.
In order to investigate the influence of changes in pCO2 on the fractional packed cell volume (FPCV, hematocrit) of whole blood, a device for measuring the conductivity was developed. This method allows an instantaneous and continuous determination of the FPCV, because the erythrocyte membrane has insulating properties, and, consequently, the resistance of blood depends on the relative cell volume. The steady state and transient relationships between FPCV and acid-base levels were investigated by combining this method with simultaneous recordings of pCO2. The experiments showed that addition of CO2 caused an increase in the resistance of whole blood, whereas the resistance of separated plasma decreased slightly and the resistance of true plasma remained almost constant. The change in the FPCV (delta H) can be described by a linear function of pH or log pCO2 (formula: see text). The transient response of the resistance, after a stepwise increase in the CO2 content, was found to be the slowest process in attaining an acid-base equilibrium. In blood with acetazolamide, the time courses of changes in pH and pCO2 were retarded, whereas the time course of the resistance change reflecting the swelling of the erythrocytes was nearly the same (T 50 approximately equal to 4 s). This may indicate a rate-limited water shift due to a slight water permeability of the erythrocyte membrane.
为了研究二氧化碳分压（pCO2）变化对全血中红细胞压积（FPCV，血细胞比容）的影响，开发了一种用于测量电导率的装置。由于红细胞膜具有绝缘特性，因此这种方法可以即时连续地测定红细胞压积，进而血液的电阻取决于相对细胞体积。通过将该方法与pCO2的同步记录相结合，研究了红细胞压积与酸碱水平之间的稳态和瞬态关系。实验表明，添加二氧化碳会导致全血电阻增加，而分离血浆的电阻略有下降，真正血浆的电阻几乎保持不变。红细胞压积的变化（δH）可用pH或log pCO2的线性函数来描述（公式：见原文）。在二氧化碳含量逐步增加后，发现电阻的瞬态响应是达到酸碱平衡过程中最慢的过程。在含有乙酰唑胺的血液中，pH和pCO2的变化时间进程延迟，而反映红细胞肿胀的电阻变化时间进程几乎相同（T50约等于4秒）。这可能表明由于红细胞膜的轻微水渗透性导致水转移速率受限。
