Sakamoto K, Sunaga R, Nakamura K, Sato Y, Fujii M, Kanai H, Tsuchida T, Ueno A, Kanai N, Hasegawa K
Department of Clinical Engineering, School of Allied Sciences, Kitasato University, Kanagawa, Japan.
Ann N Y Acad Sci. 1999 Apr 20;873:77-88. doi: 10.1111/j.1749-6632.1999.tb09452.x.
Erythrocyte orientation and deformation cause differences in impedance between flowing and resting blood. Through theoretical calculation and experimental measurements, we studied the effects of these factors on blood impedance. The size and shape of the erythrocyte and the conductivity of the interior medium of the erythrocyte change when the osmotic pressure of plasma is changed. From experimental results, we obtained the following: when the size of the erythrocyte becomes larger than the normal size due to the osmotic pressure change, the beta dispersion frequency decreases and the intra- and extracellular fluid resistance increase. These experimental results corroborate that the change of tissue impedance like muscle impedance during hemodialysis is caused by the change of the fluid distribution and the change of ionic concentration of the electrolyte in tissues during hemodialysis. Also, we could estimate the relative change value of the intra- and extracellular fluid volume by the impedance method, if there were no ionic concentration change in the electrolyte. It would be very difficult to estimate the absolute change value of them because a shadow effect due to the cells depends greatly upon the shape and size of the cells and the cell concentration.
红细胞的取向和变形导致流动血液和静止血液之间的阻抗差异。通过理论计算和实验测量，我们研究了这些因素对血液阻抗的影响。当血浆渗透压改变时，红细胞的大小和形状以及红细胞内部介质的电导率会发生变化。从实验结果中，我们得到以下结论：当红细胞因渗透压变化而变得比正常尺寸大时，β分散频率降低，细胞内和细胞外液电阻增加。这些实验结果证实，血液透析期间组织阻抗（如肌肉阻抗）的变化是由血液透析期间组织中流体分布的变化和电解质离子浓度的变化引起的。此外，如果电解质中没有离子浓度变化，我们可以通过阻抗法估计细胞内和细胞外液体积的相对变化值。由于细胞产生的阴影效应在很大程度上取决于细胞的形状和大小以及细胞浓度，因此很难估计它们的绝对变化值。
