Background: Continuous renal replacement therapy in the treatment of patients with active COVID-19 is frequently complicated by thrombosis in the extracorporeal circuit resulting in reduced filter lifespan, necessitating a revisited anticoagulation strategy.

Methods: The standard regional citrate anticoagulation dose of 2.2 mmol/l was increased to a starting dose of 3.0 mmol/l and routine thrombosis prophylaxis with low-molecular-weight heparin was adjusted from a single dose of nadroparin 2850 IU to 5700 IU twice daily. In a non-randomised cohort study, the efficacy of high-dose anticoagulation was compared with a control group with standard anticoagulation.

Results: Eleven COVID-19 patients requiring continuous renal replacement therapy were included, 42 filter sets in the control group and 37 filter sets in the high-dose anticoagulation group. The median filter lifespan was 48 hours in the high-dose anticoagulation compared with 18 hours in the control group (p<0.001). No significant effect on ionised calcium levels was observed in the high-dose group.

Conclusion: The combination of high-dose regional citrate anticoagulation and increased-dose LMWH appears to prolong filter lifespan in patients with COVID-19.