Extracorporeal blood purification with Oxiris? filter in critically ill patients with COVID-19 requiring continuous renal replacement therapy

Introduction: Severe COVID-19 is associated with a dysregulated immune response that usually leads to cytokine release syndrome. This study aimed to compare the use of extracorporeal blood purification therapy (Oxiris (R)) versus standard continuous renal replacement therapy (CRRT) in critically-ill patients with severe COVID-19.Methods: This was a national, multicenter, retrospective study of patients with COVID-19 admitted to the intensive care unit (ICU) between March and October 2020 who required CRRT. Patients were categorized into two groups: Oxiris (R) CRRT and standard CRRT. The primary outcome was the number of patients alive and ventilator-free at 30-days post-CRRT treatment. Key secondary endpoints included change in inflammatory markers, Sequential Organ Failure Assessment (SOFA) scores, and PaO2/FiO(2) ratio at 24- and 72-h post Oxiris (R) initiation.Results: Thirty-five patients received Oxiris (R) CRRT and 23 patients received standard CRRT. The primary outcome was 31.4% in the Oxiris (R) group versus 4.3% in the standard CRRT group (adjusted odds ratio 5.97, 95% confidence interval [CI], 0.64-55.6; p = 0.117). In the Oxiris (R) group, interleukin-6 (IL-6) concentrations significantly decreased at 24 and 72-h (p = 0.033) and PaO2/FiO(2) ratio significantly increased at 24 and 72 h after Oxiris (R) initiation (p = 0.001). There was no significant change in SOFA scores at 24- and 72-h after Oxiris (R) initiation.Conclusion: The number of patients alive and ventilator-free at 30-days was higher in the Oxiris (R) group than that in the standard CRRT group; however, the difference did not reach statistical significance after adjusting for the baseline severity of illness. There was a significant reduction in IL-6 and significant improvement in PaO2/FiO(2) ration after Oxiris (R) CRRT initiation.