Schneditz Daniel, Zierler Edda, Vanholder Raymond, Eloot Sunny
Institute of Physiology, Medical University of Graz, Graz, Austria.
Nephrology Section, Department of Internal Medicine, Ghent University Hospital, Gent, Belgium.
Clin Hemorheol Microcirc. 2014;58(3):455-69. doi: 10.3233/CH-131802.
It was the aim to examine the fluid flow in blood and dialysate compartments of highly permeable hollow fiber dialyzers where internal filtration contributes to solute removal but where excessive filtration bears a risk of cell activation and damage. Flow characteristics of high- (HF) and low-flux (LF) dialyzers were studied in lab-bench experiments using whole bovine blood. Measurements obtained under different operating conditions and under zero net ultrafiltration were compared to theoretical calculations obtained from a mathematical model. Experimental resistances in the blood compartment were within ±2% of those calculated from the model when dialysate was used as a test fluid. With whole blood, the experimental resistances in the blood compartment were only 81.8 ± 2.8% and 83.7 ± 4.3% of those calculated for the LF and HF dialyzer, respectively. Surprisingly, measured blood flow resistance slightly but significantly decreased with increasing flow rate (p < 0.001). Mathematical modeling confirmed this decrease both in LF and HF dialyzers which was accompanied by a concomitant decrease in internal filtration fraction, while overall internal filtration increased. The increase in internal filtration when increasing blood flow is associated with a beneficial reduction in internal filtration fraction. Concerns of increased hemoconcentration when increasing blood flow therefore appear to be unwarranted.
本研究旨在考察高通透性中空纤维透析器血液和透析液腔室中的流体流动情况，在这类透析器中，内部过滤有助于溶质清除，但过度过滤存在细胞激活和损伤风险。在实验室实验中，使用全牛血研究了高通量（HF）和低通量（LF）透析器的流动特性。将在不同操作条件下和零净超滤情况下获得的测量结果与从数学模型得到的理论计算结果进行比较。当使用透析液作为测试流体时，血液腔室中的实验阻力在模型计算值的±2%范围内。对于全血，血液腔室中的实验阻力分别仅为LF和HF透析器计算值的81.8±2.8%和83.7±4.3%。令人惊讶的是，测量的血流阻力随流速增加略有但显著降低（p<0.001）。数学建模证实了LF和HF透析器中均存在这种降低，同时内部过滤分数随之降低，而总体内部过滤增加。血流增加时内部过滤的增加与内部过滤分数的有益降低相关。因此，关于血流增加时血液浓缩增加的担忧似乎没有根据。
