Macías Nicolás, Vega Almudena, Abad Soraya, Aragoncillo Inés, García-Prieto Ana María, Santos Alba, Torres Esther, Luño Jose
Department of Nephrology, Hospital General Universitario Gregorio Marañón, Madrid, Spain.
Clin Kidney J. 2018 Dec 15;12(3):447-455. doi: 10.1093/ckj/sfy097. eCollection 2019 Jun.
New high-retention onset dialysers have shown improved efficacy in the elimination of uraemic toxins, and their depurative capacity has been compared with high convective volumes of online haemodiafiltration. Haemodialysis (HD) using high-flux membranes leads to convective transport by internal filtration [direct filtration (DF)/backfiltration (BF)] and allows the removal of middle molecules (MMs). The aim of this study was to assess solute transport mechanisms in expanded HD (HDx).
In 14 4-h HDx sessions with Theranova-500 dialysers under similar dialysis conditions (blood flow 400 mL/min, dialysate flow 700 mL/min, dialysate temperature 35.5°C), pressures at the inlet and outlet of both dialyser compartments ( , , and ) were collected hourly to estimate DF/BF volumes by semi-empirical methods. Uraemic toxins with various molecular weights were measured pre-dialysis, at 1 h (pre-filter and post-filter) and post-dialysis to calculate molecules' reduction over time and dialyser clearances.
Ultrafiltration was 1.47 ± 0.9 L and Kt/V 1.74 ± 0.3. Hydrodynamic data ( : 259 ± 39, : 155 ± 27, : 271 ± 30, : 145 ± 29 mmHg and oncotic pressure 22.0 ± 3.5 mmHg) allowed the estimation of DF/BF rates. DF flow ranged from 29.5 ± 4.2 to 31.3 ± 3.9 mL/min and BF flow ranged from 25.1 ± 2.3 to 23.4 ± 2.6 mL/min. The highest calculated DF volume was 7506.8 ± 935.3 mL/session. Diffusive clearances ( ) of all solutes were higher than their convective transport (all P < 0.001) except for prolactin (23 kDa) clearances, which showed no differences. Total clearances of all solutes were correlated with their (ρ = 0.899-0.987, all P < 0.001) and Kt/V correlated with all reduction rates (ρ = 0.661-0.941, P = 0.010 to <0.001). DF flow was only associated with urea (ρ = -0.793, P = 0.001), creatinine (ρ = -0.675, P = 0.008) and myoglobin clearance (ρ = 0.653, P = 0.011).
Results suggest that diffusive transport is a main mechanism of MM elimination in HDx. HDx offers an efficient depuration of MM without the need for high convective volumes.
新型高保留量起始透析器在清除尿毒症毒素方面已显示出更高的疗效，并且已将其净化能力与高通量在线血液透析滤过进行了比较。使用高通量膜的血液透析（HD）通过内部过滤[直接过滤（DF）/反渗 透（BF）]导致对流运输，并允许清除中分子（MMs）。本研究的目的是评估扩展血液透析（HDx）中的溶质转运机制。
在14次使用Theranova - 500透析器进行的4小时HDx治疗中，在相似的透析条件下（血流量400 mL/分钟，透析液流量700 mL/分钟，透析液温度35.5°C），每小时收集透析器两个隔室入口和出口处的压力（ 、 、 和 ），通过半经验方法估算DF/BF量。在透析前、1小时（滤器前和滤器后）和透析后测量各种分子量的尿毒症毒素，以计算分子随时间的减少量和透析器清除率。
超滤量为1.47±0.9 L，Kt/V为1.74±0.3。流体动力学数据（ ：259±39， ：155±27， ：271±30， ：145±29 mmHg，胶体渗透压22.0±3.5 mmHg）允许估算DF/BF速率。DF流量范围为29.5±4.2至31.3±3.9 mL/分钟，BF流量范围为25.1±2.3至23.4±2.6 mL/分钟。计算出的最高DF量为7506.8±935.3 mL/次治疗。除催乳素（23 kDa）清除率无差异外，所有溶质的扩散清除率（ ）均高于其对流运输清除率（所有P < 0.001）。所有溶质的总清除率与其 相关（ρ = 0.899 - 0.987，所有P < 0.001），Kt/V与所有减少率相关（ρ = 0.661 - 0.941，P = 从0.010至<0.001）。DF流量仅与尿素（ρ = -0.793，P = 0.001）、肌酐（ρ = -0.675，P = 0.008）和肌红蛋白清除率（ρ = 0.653，P = 0.011）相关。
结果表明，扩散运输是HDx中MM清除的主要机制。HDx无需高通量对流即可有效净化MM。
