Heparin Administration in CRRT: Prefilter vs. Postfilter

Anticoagulation Principles in CRRT

Systemic anticoagulation with heparin is commonly used in CRRT when patients do not have increased bleeding risk, as recommended by the American Society of Nephrology 1, 2
Prefilter administration of heparin allows the anticoagulant to immediately mix with the blood before it enters the filter, optimizing the anticoagulant effect throughout the entire extracorporeal circuit 1
The choice of anticoagulant should be determined by patient characteristics, local expertise, ease of monitoring, and pharmacy considerations, according to the Kidney Disease Outcomes Quality Initiative 1

When using prefilter heparin, safety monitoring is recommended through measurement of activated clotting times (ACT) or systemic partial thromboplastin time (PTT) to minimize the risk of bleeding complications 1
Routine measurement of platelets should be performed to monitor for heparin-induced thrombocytopenia, a potential side effect of heparin therapy 1

For patients with high bleeding risk, regional citrate anticoagulation is preferred over heparin when there are no contraindications for citrate, as recommended by the American Journal of Kidney Diseases 2, 3
Regional citrate anticoagulation requires frequent measurements of post-filter and serum-ionized calcium to appropriately titrate the dose of citrate and calcium replacement solutions, according to the Kidney International guidelines 1, 4

In patients with heparin-induced thrombocytopenia (HIT), all heparin must be stopped, and direct thrombin inhibitors (such as argatroban) or Factor Xa inhibitors should be used instead, as recommended by the American College of Cardiology 2, 3

When using regional citrate anticoagulation, monitoring of systemic acid-base balance is advisable, particularly in patients at high risk for citrate accumulation, according to the Kidney International guidelines 1, 4
Standardized anticoagulation administration and monitoring protocols are essential for safe implementation of any anticoagulation strategy in CRRT, as emphasized by the American Society of Nephrology 3, 4