Since the emergence of the new strain of betacoronavirus (SARS-CoV-2) and its important clinical repercussions, it has been described that patients with its associated pneumonia (COVID-19) have high rates of thrombotic events, including reduction in the dialyzers patency when undergoing renal replacement therapy. Several strategies for preventing the early loss of dialysers are described, and regional anticoagulation based on citrate is the preferred modality for preventing this complication. On the other hand, in patients with SARS-CoV-2 there are already descriptions of endothelial inflammation and activation of the coagulation cascade, including studies demonstrating the benefit of heparinization of these patients. Thus, this study aims to compare two different anticoagulation strategies in patients infected with COVID-19 with continued venovenous hemodialysis (CVVHD). From the indication of CVVHD, patients will be screened according to eligibility criteria and, if they fit these parameters, they will be randomized into two groups: Group A - Standard regional anticoagulation based on Citrate associated with infusion of low doses of unfractionated heparin 10ui/kg/hour and Group B - Standard regional anticoagulation based on Citrate only. Patients will be randomized in blocks and followed for 72 hours. The primary endpoint is dialyzer patency at the end of 72 hours of clinical follow-up. Secondary objectives will be mortality, bleeding rate, drop in hematimetric indices, urea sieving, filter time in hours, down time of therapy, system and dialyser pressures (PBE and PTM). All patients will undergo a standard procedure with a prescribed dose of 30mL/Kg/H, blood flow of 150mL/minute and polysulfone dialyzer.

After randomization, patients will be allocated to one of two groups:

Control group (n = 45): patients on continuous hemodialysis (blood flow 150 ml / min, dose of 30 ml / kg / h) receiving anticoagulation with sodium citrate at 4 mmol / l. The dialysis system pressures, dialyzer patency and duration and bleeding rate will be assessed for 72 hours;

Intervention group (n = 45): patients on continuous hemodialysis (blood flow 150 ml / min, dose of 30 ml / kg / h) receiving anticoagulation with sodium citrate at 4 mmol / l associated with unfractionated heparin at 10U / Kg / h. The dialysis system pressures, dialyzer patency and duration and bleeding rate will be assessed for 72 hours.

Inclusion Criteria:

• Confirmed or probable SARS-CoV-2 infection;
• Presence of acute kidney injury with indication and agreement between ICU and nephrology teams for the introduction of renal continuous venous venous hemodialysis.

Exclusion Criteria:

• Hypersensitivity to any of the substances used in the study (Citric acid dextrosol 2.2% and unfractionated heparin);
• Previous diagnosis of coagulopathy or thrombophilia;
• Contraindication to the use of unfractionated heparin by the assistant team;
• Risk of citrate poisoning - (Lactate> 30mg / dL, RNI> 2.5, Total bilirubin> 15mg / dL);
• Pregnancy