ABSTRACT
Background: Patients with COVID are more likely to have systemic thrombotic events. Although it has been theorized that those on CRRT also have an increased rate of filter loss due to clotting. If COVID-positive patients are more likely to clot their filter than other patients on CRRT, a more aggressive anticoagulation strategy may be worthwhile. This could result in longer filter lifespan, less circuit down time, which would result in improved clearance, lower costs, less risk of iatrogenic blood loss, and less wasted nursing time. If there is no difference in filter lifespan between COVID positive and negative patients, then more aggressive anticoagulation would result only in added risk without a clear benefit. Methods: We analyzed COVID data on patients in a related unblinded prospective randomized trial, in which patients are assigned to either pre-filter CVVH or CVVHD. The standard treatment protocol at the University of Iowa is to use citrate anticoagulation with a blood flow rate of 200 mL/min and a dose of 25 mL/kg/hr. The primary outcome is average filter life, and secondary outcomes are mortality, intensive care unit LOS, hospital LOS, and renal recovery. Results: A total 30 patients using a total of 90 filters from March 25 to May 20, 2020 were evaluated (Table 1). The average filter life in COVID-positive patients was 37.4 +/- 35.8 compared to 33.1 +/- 26.7 in COVID-negative patients (p = 0.55). However, COVID-19 patients were more likely to receive heparin anticoagulation in addition to citrate. Conclusions: Contrary to other reports, in this retrospective, unadjusted analysis of CRRT patients, the presence of COVID-19 did not decrease average filter life. Further research is needed regarding the appropriate anticoagulation strategy in COVID-19 positive patients.