Wednesday March 21, 2007
Citrate in CRRT


Q; Why we use citrate (when heparin is not used) to avoid filter clotting in CRRT / CVVHD (continuous renal replacement therapy) ?

A; Citrate combines with calcium and cause extracorporeal chelation of calcium and blocks calcium dependent steps of clotting cascade.

When extracorporeal blood mix with venous blood, the ionized calcium level get resotred and systemic anticoagulation get avoided. Also citrate get metabolized via liver and chelated calcium get release back in circulation which prevents hypocalcemia (though frequent checks required particularly in liver insuff.).

Related: Very nice review article: Acute Renal Failure in ICU (reference: nephrologyrounds.org, december 2006, volume 4, issue 10) - pdf file