Anticoagulation in Continuous Renal Replacement Therapy

Dialysis fiber clotting can be a major issue encountered during prolonged sessions of continuous renal replacement therapy (CRRT) in the ICU. It can lead to extended circuit down time while replacing the filter, leading to decreased dialysis efficacy and dose. It also leads to higher cost and can be time and resource-consuming.

Different modalities can be implemented to minimize the risk of fiber clotting. Higher blood flow and changing replacement fluid to pre filter can help but may not always be practical or effective, and use of anticoagulants may be necessary.

Heparin is typically used in many institutions due to availability and familiarity with its use. However heparin is not very effective in preventing fiber clotting and can lead to systemic anticoagulation effect.

Regional Citrate anticoagulation (RCA) can be an excellent, more effective alternative to heparin. It works by chelating calcium from the blood circulating in the filter, leading to inactivating the clotting cascades. This leads to virtually clot free blood (See figure above). Calcium then is replaced before blood is returned to the patient.

While RCA is the superior method in terms of efficacy, it needs specialized nursing training and well-established protocols to facilitate accurate calcium replacement. If those protocols are not followed precisely, consequences can be dire, and my include severely low calcium levels in the serum.