肝素和柠檬酸盐抗凝连续静脉-静脉血液透析滤过中的钙通量。

Calcium flux in continuous venovenous haemodiafiltration with heparin and citrate anticoagulation.

机构信息

Launceston General Hospital, Launceston, TAS, Australia.

出版信息

Crit Care Resusc. 2011 Jun;13(2):72-81.

Abstract

BACKGROUND

Calcium chelation with citrate is an effective alternative to heparin for anticoagulation of the extracorporeal circuit during continuous venovenous haemodiafiltration (CVVHD-F). Calcium release occurs upon citrate metabolism; however, ultrafiltration of citrate-bound and free ions also occurs.

OBJECTIVE

To quantify calcium loss and improve understanding of calcium homeostasis in CVVHD-F.

METHODS

Calcium loss was prospectively quantified from heparinised and citrated circuits in consecutive intensive care patients requiring CVVHD-F. CVVHD-F prescription and anticoagulation choice was by the treating intensivist using commercial solutions (Gambro, Lundia, Sweden). Sample sets comprising arterial, prefilter and postfilter blood and an effluent sample were analysed for ionised total calcium (iCa(2+)) and magnesium levels. Flow rates were then used to calculate calcium flux. Citrate dose (predilution rate) and calcium replacement followed unit protocols to maintain a circuit iCa(2+) concentration of 0.3-0.5 mmol/L and an arterial iCa(2+) concentration of 0.8-1.1 mmol/L.

RESULTS

26 heparinised circuits and 22 citrated circuits in 13 patients were included; 334 sample sets were tested. For target extracorporeal blood flows of 200 mL/min, mean predilution Prismocitrate 10/2 flows were 1660 mL/h, delivering 2.42 mmol citrate per litre of blood. For heparin, mean predilution flows of Hemosol B0 were 2058mL/h. Mean calcium loss was 4.01 mmol/h from citrate anticoagulated circuits versus a gain of 0.24mmol/h from heparinised circuits (P < 0.001). Despite calcium replacement, citrate patients experienced a mean calcium loss of 1.12 mmol/h (SD, 0.70; 95% CI 1.0-1.22mmol/h; P < 0.001). Calculated effective diffusion volume (Q(E)) for calcium was closer to total blood water volume in heparin circuits and closer to plasma water volume in citrate circuits.

CONCLUSIONS

Despite supplementation to maintain arterial iCa(2+) levels, citrate anticoagulation results in a net calcium deficit. An equation for estimating required citrate dose may allow revision of citrate dosing protocols.

摘要

背景

柠檬酸盐螯合钙是体外连续静脉-静脉血液透析滤过（CVVHD-F）抗凝替代肝素的有效方法。柠檬酸盐代谢时会释放钙；然而，柠檬酸盐结合和游离离子也会发生超滤。

目的

定量钙丢失并提高对 CVVHD-F 中钙平衡的理解。

方法

连续对需要 CVVHD-F 的重症监护患者的肝素化和柠檬酸盐化回路中进行前瞻性定量钙丢失。CVVHD-F 处方和抗凝选择由主治重症监护医师使用商业溶液（瑞典伦迪亚 Gambro）进行。采集包括动脉、预滤器和后滤器血液以及流出液样本，用于分析离子化总钙（iCa(2+))和镁水平。然后使用流量速率计算钙通量。根据单位方案进行柠檬酸盐剂量（预稀释率）和钙替代，以维持回路 iCa(2+)浓度为 0.3-0.5mmol/L 和动脉 iCa(2+)浓度为 0.8-1.1mmol/L。

结果

纳入 13 名患者的 26 个肝素化回路和 22 个柠檬酸盐化回路；共检测 334 个样本组。对于目标体外血液流量为 200mL/min，预稀释 Prismocitrate 10/2 的平均流速为 1660mL/h，每升血液输送 2.42mmol 柠檬酸盐。对于肝素，Hemosol B0 的平均预稀释流速为 2058mL/h。柠檬酸盐抗凝回路的平均钙丢失为 4.01mmol/h，肝素化回路的钙丢失为 0.24mmol/h（P<0.001）。尽管进行了钙替代，但柠檬酸盐患者的平均钙丢失为 1.12mmol/h（SD，0.70；95%CI 1.0-1.22mmol/h；P<0.001）。钙的计算有效扩散体积（Q(E)) 在肝素回路中更接近总血液水体积，在柠檬酸盐回路中更接近血浆水体积。