Division of Nephrology and Hypertension, Henry Ford Health System, Detroit, Mich., USA.
Blood Purif. 2010;29(2):204-9. doi: 10.1159/000245648. Epub 2010 Jan 8.
Large-scale adoption of regional citrate anticoagulation (RCA) is prevented by risks of the technique as practiced traditionally. Safe RCA protocols with automated delivery on customized dialysis systems are needed.
We applied kinetic analysis of solute fluxes during RCA to design a protocol for sustained low-efficiency dialysis (SLED) for critically ill patients. We used a high-flux hemodialyzer, a zero-calcium (Ca) dialysate, a dialysis machine with online clearance and access recirculation monitoring, and a separate optical hematocrit (Hct) sensor. Flow rates were Q(B) = 200 ml/min for blood; Q(D) = 400 ml/min for dialysate, with Na = 140 mmol/l and HCO(3) = 32 mmol/l; Q(citrate) = 400 ml/h of acid citrate dextrose A; ultrafiltration as indicated. The Q(Ca) was infused into the return blood line, adjusted hourly based on online Hct and a <24-hour-old albumin level.
Using the SLED-RCA protocol in an anhepatic, ex vivo dialysis system, ionized Ca (iCa) was >1 mmol/l in the blood reservoir and <0.3 mmol/l in the blood circuit after citrate but before Ca infusion (Q(Ca)) with normal electrolyte composition of the blood returning to the reservoir. Clinically, SLED-RCA completely abrogated clotting, without adverse electrolyte effects. The Q(Ca) prediction algorithm maintained normal systemic iCa (0.95-1.4 mmol/l) in all patients. The high citrate extraction on the dialyzer prevented systemic citrate accumulation even in shock liver patients. Safety analysis shows that building a dialysis system for automated SLED-RCA is feasible.
Using predictive Q(Ca) dosing and integrating control of the infusion pumps with the dialysis machine, SLED-RCA can be near-automated today to provide a user-friendly and safe system.
传统实践中，区域枸橼酸抗凝（RCA）技术存在风险，阻碍了其大规模应用。需要制定安全的 RCA 方案，以实现定制透析系统的自动化给药。
我们应用溶质通量动力学分析，为危重症患者设计持续低效透析（SLED）的 RCA 方案。采用高通量血液透析器、无钙（Ca）透析液、具有在线清除率和通路再循环监测功能的透析机，以及独立的光学血细胞比容（Hct）传感器。血流速度为：血液 Q(B) = 200 ml/min；透析液 Q(D) = 400 ml/min，其中 Na = 140 mmol/l，HCO(3) = 32 mmol/l；枸橼酸葡萄糖酸钙 A（acid citrate dextrose A）酸速 Q(citrate) = 400 ml/h；根据需要超滤。Q(Ca)以静脉输注方式输入回输血液管路，根据在线 Hct 和 24 小时内白蛋白水平，每小时调整一次。
在无肝、离体透析系统中，采用 SLED-RCA 方案，枸橼酸盐给药后、Ca 输注前（Q(Ca)），血液储槽中的离子钙（iCa）>1 mmol/l，而血液回路中的 iCa <0.3 mmol/l，且返回储槽的血液电解质组成正常。临床研究中，SLED-RCA 可完全消除凝血，且无电解质异常。Q(Ca)预测算法可维持所有患者的正常全身 iCa（0.95-1.4 mmol/l）。高容量的透析器枸橼酸盐清除可防止全身性枸橼酸盐蓄积，即使在肝功能衰竭患者中也如此。安全性分析表明，构建自动化 SLED-RCA 的透析系统是可行的。
通过预测性 Q(Ca)剂量给药，并将输注泵的控制与透析机集成，SLED-RCA 可在今天实现近乎自动化，从而提供一个用户友好且安全的系统。
