Prefilter Fluid Administration to Reduce Clotting in CRRT

Mechanisms of Reducing Filter Clotting

Prefilter fluid administration dilutes the blood before it enters the hemofilter, enhancing the achievable ultrafiltration rate and reducing the risk of filter clotting 1, 2
This approach is particularly beneficial in high-volume continuous venovenous hemofiltration (CVVH) where filter clotting is more common 1

Prefilter fluid administration can be used in combination with post-dilution when extracorporeal clearance is limited by achievable blood flow 1, 2

Replacement fluid used for prefilter administration should contain physiologic concentrations of electrolytes, except in patients with extreme imbalances 1, 2
Either lactate or bicarbonate can be used as buffer in most CRRT patients, but bicarbonate is preferred in patients with lactic acidosis, liver failure, or when using high-volume hemofiltration 1, 2
Avoid fluids with supra-physiologic glucose concentrations as they can lead to excessive glucose intake and hyperglycemia 1, 2

The choice of anticoagulant should be determined by patient characteristics, local expertise, nursing comfort, ease of monitoring, and pharmacy considerations 3, 4

For patients with heparin-induced thrombocytopenia, all heparin must be stopped, and direct thrombin inhibitors or Factor Xa inhibitors should be used instead 5, 6
In thrombocytopenic patients without contraindications to citrate, regional citrate anticoagulation is recommended over heparin 6

The American Journal of Kidney Diseases recommends using unfractionated or low-molecular-weight heparin as anticoagulation during CRRT for patients who cannot receive citrate 7
Direct thrombin inhibitors (argatroban) or Factor Xa inhibitors should be used in patients with heparin-induced thrombocytopenia 8

The KDIGO guidelines recommend bicarbonate over lactate as a buffer in dialysate and replacement fluid for CRRT in patients with acute kidney injury (AKI) 9
Bicarbonate is strongly recommended (1B recommendation) over lactate for patients with AKI and circulatory shock 9
Bicarbonate is suggested (2B recommendation) over lactate for patients with AKI and liver failure and/or lactic acidemia 9