Nephrology Section, Department of Internal Medicine, Ghent University Hospital, Gent,
Nephrol Dial Transplant. 2012 Aug;27(8):3278-83. doi: 10.1093/ndt/gfs060. Epub 2012 Apr 5.
Convective dialysis strategies are superior in the removal of protein-bound uraemic retention solutes. Mid-dilution and mixed-dilution haemodiafiltration (HDF), both combining pre-dilution and post-dilution, are promising options to further improve removal capacity and have been shown of additional benefit for large middle molecules. In this study, we compared the removal of small water-soluble and protein-bound solutes in post-dilution versus mid-dilution HDF.
Fourteen chronic haemodialysis (HD) patients were included in this crossover study. Patients were kept for 4 weeks on high-flux HD. On the mid-week session of Weeks 3 and 4, either post-dilution or reversed mid-dilution HDF were applied, in random order. Blood and dialysate flows were maintained at 300 and 800 mL/min, while the substitution flow was 75 mL/min in post-dilution and 150 mL/min in mid-dilution HDF. Based on the data collected during the sessions under study, extraction ratio (ER) and reduction ratio (RR) of small water-soluble and protein-bound solutes were calculated, as well as total solute removal (TSR) based on spent dialysate.
No differences were observed for TSR, ER and RR for protein-bound solutes. For small water-soluble solutes, ER in post-dilution HDF was significantly higher than in mid-dilution HDF: 0.92 ± 0.02 versus 0.87 ± 0.04 for urea (P < 0.001), 0.92 ± 0.02 versus 0.88 ± 0.02 for creatinine (P < 0.001) and 0.84 ± 0.02 versus 0.82 ± 0.03 for uric acid (P = 0.009). TSR and RR were, however, not different due to the lower inlet concentrations with post-dilution HDF.
TSR of mid-dilution and post-dilution HDF was not different for both small water-soluble and protein-bound compounds. Both strategies in the setting as applied in this study are as adequate for the removal of these solutes.
对流透析策略在去除蛋白结合型尿毒症潴留溶质方面具有优势。中稀释和混合稀释血液透析滤过（HDF）均结合预稀释和后稀释，是进一步提高清除能力的有前途的选择，并已被证明对大分子量物质有额外的益处。在这项研究中，我们比较了后稀释与中稀释 HDF 对小分子水溶性和蛋白结合性溶质的清除效果。
这项交叉研究纳入了 14 名慢性血液透析（HD）患者。这些患者在高通量 HD 治疗 4 周。在第 3 周和第 4 周的周中治疗期间，随机应用后稀释或反向中稀释 HDF。血液和透析液流量均保持在 300 和 800mL/min，而在后稀释 HDF 中替代液流量为 75mL/min，在中稀释 HDF 中替代液流量为 150mL/min。根据研究期间收集的数据，计算小分子水溶性和蛋白结合性溶质的提取率（ER）和还原率（RR），以及基于使用过的透析液的总溶质清除率（TSR）。
对于小分子水溶性溶质，后稀释 HDF 的 ER 显著高于中稀释 HDF：尿素为 0.92±0.02 对 0.87±0.04（P＜0.001），肌酐为 0.92±0.02 对 0.88±0.02（P＜0.001），尿酸为 0.84±0.02 对 0.82±0.03（P=0.009）。然而，由于后稀释 HDF 的入口浓度较低，TSR 和 RR 没有差异。
对于小分子水溶性和蛋白结合性化合物，中稀释和后稀释 HDF 的 TSR 没有差异。在本研究中应用的这两种策略对于这些溶质的清除效果都是足够的。
