Kashiwagi Tetsuya, Sato Kazuto, Kawakami Seiko, Kiyomoto Masayoshi, Enomoto Miho, Suzuki Tatsuya, Genei Hirokazu, Nakada Hiroaki, Iino Yasuhiko, Katayama Yasuo
Division of Neurology, Nephrology, and Rheumatology, Department of Internal Medicine, Nippon Medical School, Tokyo, Japan.
J Nippon Med Sch. 2013;80(2):119-30. doi: 10.1272/jnms.80.119.
Hemodialysis is a treatment in which uremic toxins and excess water content are removed from the blood with a dialyzer and dialysis fluid. The efficiency of hemodialysis is strongly influenced by the following 3 parameters: the blood flow rate (QB), the dialysis fluid flow rate (QD), and the overall mass transfer area coefficient (K0A), an index of a dialyzer's performance. The flow ratio (QB : QD) to obtain a well-balanced dialysis efficiency is generally said to be 1 : 2. In Japan, the QB is controlled independently (from 200 to 250 mL/min) depending on individual conditions. However, the QD is usually set at around 500 mL/min regardless of the QB.
To investigate the effect on dialysis efficiency of decreasing the QD from 500 to 400 mL/min, 12 patients were divided into two groups: one in which the QB was 150 mL/min, with 1.3-m(2) membranes; and another in which the QB was 200 mL/min, with 1.6-m(2) membranes. We defined the conditions with the QD of 500 mL/min as condition A, and that with the QD of 400 mL/min as condition B. Each operating condition was assigned for 2 weeks as crossover trials. To evaluate solute removal, we calculated clearance, reduction rate, removal amount, clear space, the clear space rate, and albumin leakage. Furthermore, when dialysis efficiency decreased in condition B, we performed a supplementary test: we calculated the QB with the K0A equation to achieve a dialysis efficiency equivalent to that in condition A, defined as condition B', as the operating condition with the calculated QB and a QD of 400 mL/min, and re-evaluated.
In condition B, a QB of 150 mL/min had no effect on the dialysis efficiency;whereas with a QB of 200 mL/min, slight yet significant differences were observed in the clearance of small molecular weight solutes. Condition B' (QB=210 mL/min) showed an equivalent or greater dialysis efficiency and demonstrated an association with theoretical values.
In hemodialysis, the flow ratio (QB : QD) should be maintained at 1 : 2 to obtain a well-balanced dialysis efficiency. The present study has shown that the QD can be decreased while maintaining this flow ratio. A well-balanced QD setting can be financially and environmentally conscious. In addition, use of the K0A equation is a highly effective method to calculate a QB that allows an expected dialysis efficiency to be achieved in case the QD needs to be decreased uniformly, as when dialysis fluid is in short supply during times of disaster.
血液透析是一种通过透析器和透析液从血液中清除尿毒症毒素和过多水分的治疗方法。血液透析的效率受到以下三个参数的强烈影响：血流量（QB）、透析液流速（QD）以及总传质面积系数（K0A），后者是透析器性能的一个指标。一般认为，要获得均衡的透析效率，流量比（QB : QD）应为1 : 2。在日本，QB会根据个体情况独立控制（范围为200至250 mL/分钟）。然而，无论QB如何，QD通常设定在500 mL/分钟左右。
为了研究将QD从500 mL/分钟降至400 mL/分钟对透析效率的影响，12名患者被分为两组：一组QB为150 mL/分钟，使用1.3平方米的透析膜；另一组QB为200 mL/分钟，使用1.6平方米的透析膜。我们将QD为500 mL/分钟的情况定义为A组，将QD为400 mL/分钟的情况定义为B组。每种操作条件作为交叉试验各分配2周。为了评估溶质清除情况，我们计算了清除率、降低率、清除量、清除空间、清除空间率以及白蛋白渗漏情况。此外，当B组的透析效率下降时，我们进行了一项补充试验：我们使用K0A方程计算QB，以达到与A组相当的透析效率，将其定义为B'组，即QB经计算且QD为400 mL/分钟的操作条件，并重新进行评估。
在B组中，QB为150 mL/分钟对透析效率没有影响；而QB为200 mL/分钟时，在小分子溶质的清除方面观察到了轻微但显著的差异。B'组（QB = 210 mL/分钟）显示出相当或更高的透析效率，并且与理论值相关。
在血液透析中，为了获得均衡的透析效率，流量比（QB : QD）应保持在1 : 2。本研究表明，在保持该流量比的同时可以降低QD。合理设置QD在经济和环境方面都具有意义。此外，当需要统一降低QD（如在灾难期间透析液供应短缺时），使用K0A方程是一种计算QB的高效方法，可实现预期的透析效率。
