Circuit clotting on continuous venovenous hemofiltration in COVID-19 patients at new england's largest health safety-net hospital

Background: The pandemic of COVID19 led to a surge in critically ill patients with severe kidney failure requiring continuous renal replacement therapy (CRRT) Primary reports rapidly showed a hypercoagulable state associated with cytokine storm representing a challenge to conduct CRRT We report our experience to face clotting on continuous venovenous hemofiltration (CVVH) with COVID19 patients Methods: We reviewed data on all admitted patients with COVID19 diagnosis and requiring CVVH at Boston Medical Center between March, 15th and May 7th, 2020 The study was approved by the institutional IRB Results: Twenty six patients were admitted to ICU with COVID19 disease and developed acute kidney injury requiring CRRT The majority of patients were males (73%), and mean age was 64 3 (+/ 9 4) years At dialysis initiation, patients showed marked inflammatory state with a median CRP of 239mg/dl (IQR 123-391 5), fibrinogen 609mg/dl (431-693), d-dimer 4,036 ng/ml (1,777-15,558) CVVH was conducted in predilution mode, with a median therapy rate of 3L/h (2 5-3 1) and a mean blood flow of 280 mL/min The median cartridge half-life from CVVH initiation was 11 8 hours (3 5-20) Twelve patients (46%) experienced CVVH circuit clotting within the first 24 hours, including 6 patients (23%) with severe recurring clotting Curative systemic anticoagulation by heparin was used in 12 patients (46%) based on hospital protocol Its use was associated with mild improvement in cartridge half-life: 15h with curative heparin dosing compare to 11 25h with no/ low dose preventive anticoagulation (nonsignificant) Of note, heparin was held prior to CRRT initiation for dialysis catheter placement and was reinitiated without bolus, which could lead to early coagulation of the filter in patients with hypercoagulable state The fatality rate was 76 9% with a median time from CVVH initiation to death of 2 5 days (1 - 8 75) Conclusions: Conducting CRRT in patients with multiorgan failure secondary to COVID19 is challenging Our experience suggests only a mild non significant improvement of clotting prevention with heparin anticoagulation at the time of cvvh initiation Further studies are warrantied to determine the optimal anticoagulation regimen