Gong D, Ji D, Xie H, Xu B, Liu Y, Li L
Research Institute of Nephrology, Jinling Hospital, Nanjing 210002, China.
Zhonghua Nei Ke Za Zhi. 2001 Mar;40(3):183-6.
To study the solute clearance during various forms of continuous renal replacement therapy(CRRT) and test the formulas that allow the prediction of the influence of dialysate and ultrafiltration flow rate on small solute removal during CRRT.
Five patients with acute renal failure were included in the study and were treated by venovenous CRRT using the PRISMA predilution system. Solute clearance of urea nitrogen(UN), creatinine(Cr), uric acid(Ua), phosphate(P) and beta(2)-microglobulin(beta(2)-M) were evaluated during CRRT with different dialysates and ultrafiltration flow rates.
The determined clearance of small molecular solutes during continuous venovenous hemofiltration (CVVH) and continuous venovenous hemodialysis(CVVHD) was similar with the following formulas: K(UF) = (Q(UF)/60) x Q(B)/(Q(B) + Q(UF)/60) (in CVVH), Kd = Q(D)/60 (in CVVHD), where K is the clearance, Q(B), Q(D) and Q(UF) are blood, dialysate and ultrafiltration flow rates, respectively. There was very significant correlation between calculated values of K(UF) and observed clearances of small solutes such as UN, Cr, Ua and P during CVVH, between calculated values of Kd and observed clearances of UN, Cr, Ua but not P during CVVHD (P < 0.001). Clearances of UN, Cr, Ua and P during CVVHD were greater than those during CVVH, but clearance of beta(2)-M during CVVHD was less than that during CVVH. Interaction between convection and diffusion was found during continuous venovenous hemodiafiltration (CVVHDF).
The previous formulas can provide with the prediction of the clearance of small molecular solutes during CVVH and CVVHD. The present results demonstrate that diffusion is more efficient in removing small solutes than convection but less efficient in removing large solutes than convection. There is interaction between convection and diffusion during CVVHDF.
研究不同形式的连续性肾脏替代治疗（CRRT）过程中的溶质清除情况，并验证能够预测透析液和超滤流速对CRRT期间小分子溶质清除影响的公式。
本研究纳入5例急性肾衰竭患者，采用PRISMA预稀释系统进行静脉-静脉CRRT治疗。在不同透析液和超滤流速的CRRT过程中，评估尿素氮（UN）、肌酐（Cr）、尿酸（Ua）、磷（P）和β2-微球蛋白（β2-M）的溶质清除情况。
在连续性静脉-静脉血液滤过（CVVH）和连续性静脉-静脉血液透析（CVVHD）过程中，小分子溶质的测定清除率与以下公式相似：K(UF) = (Q(UF)/60) × Q(B)/(Q(B) + Q(UF)/60)（CVVH中），Kd = Q(D)/60（CVVHD中），其中K为清除率，Q(B)、Q(D)和Q(UF)分别为血流量、透析液流量和超滤流量。CVVH期间，K(UF)的计算值与UN、Cr、Ua和P等小分子溶质的观察清除率之间存在非常显著的相关性；CVVHD期间，Kd的计算值与UN、Cr、Ua的观察清除率之间存在显著相关性，但与P的观察清除率无显著相关性（P < 0.001）。CVVHD期间UN、Cr、Ua和P的清除率高于CVVH，但CVVHD期间β2-M的清除率低于CVVH。在连续性静脉-静脉血液透析滤过（CVVHDF）过程中发现了对流与扩散之间的相互作用。
先前的公式可用于预测CVVH和CVVHD期间小分子溶质的清除率。目前的结果表明，扩散在清除小分子溶质方面比对流更有效，但在清除大分子溶质方面比对流效率低。CVVHDF过程中存在对流与扩散之间的相互作用。
