The human resources required to start enrollment were not available anymore.

Severe sepsis and septic shock are some of the leading causes of mortality in intensive care unit (ICU) admitted COVID-19 patients. The main cause of early mortality is the uncontrolled release of inflammatory mediators leading to cardiovascular failure. CytoSorb, a recently developed, highly biocompatible hemadsorption device has been tested, which can selectively remove inflammatory mediators from the circulation. This device is currently commercially available, and in Europe, it has been approved for clinical use. Based on experience to date, this adsorption technique may influence the immune function; removing inflammatory mediators from the blood may improve organ functions and even increase the chances of survival. CYTOAID is an observational, non-interventional study to assess the effectiveness of early cytokine adsorption therapy in critically ill patients who have been admitted to the ICU because of COVID-19 infection. Data on the applied therapy on COVID-19 patients in ICU will be collected and analyzed. The patient's examination and therapy will be applied according to the current regulations at the clinics and the current professional standards. The study does not require any additional examination or intervention.

In the early phase of sepsis, the activation of innate immunity plays a significant role. Immune cells enhance the production of pro-inflammatory mediators. These pro-inflammatory mediators are responsible for the development of immune response and the intensification of the inflammatory processes. To counteract this, anti-inflammatory mediators limit and alleviate inflammation. Critically ill septic patients with higher levels of both anti- and proinflammatory mediators are at higher risk for death. The main cause for early mortality is the uncontrolled release of inflammatory mediators leading to cardiovascular failure, while in the late phase of the disease, secondary infections and the subsequent multiorgan failure dominate due to the exhaustion of the immune functions and the subsequent insufficient protective mechanisms. Therefore, it has been suggested that the outcomes of severe sepsis can be improved by attenuating the inflammatory processes. A recently developed, highly biocompatible hemadsorption device has been tested that can selectively remove inflammatory mediators from the circulation. This device is currently commercially available, and in Europe, it has been approved for clinical use. Based on experience to date, this adsorption technique may influence the immune function; removing inflammatory mediators from the blood may improve organ functions and even increase the chances of survival.

During the study, data will be collected exclusively; the application of CytoSorb therapy will be considered by the current physician always on an individual basis. Data will be recorded during hospitalization (using the documentations of the ICU) and immediately after discharge.

This study is suitable for recording every step of medical care from the diagnosis of SARS-CoV-2 infection. To investigate the biomarkers and the genetic background that potentially play a role in the infection, biological samples will be also collected - by already indicated interventions during standard care, i.e. without additional intervention.

This study aims to describe cytokine adsorption therapy (CytoSorb) in general and to detect its most important features. The study would also like to assess the safety and cost-effectiveness of the therapy, evaluate specific interventions required during the treatment, and to assess the outcomes of the disease. This study can provide important data and expand our knowledge about COVID-19 and its treatment, as well as improve the outcomes of the disease.

Inclusion Criteria:

• Age >18 years
• confirmed COVID-19 infection
• ICU admission
• Mechanical ventilation due to COVID-19 pulmonary complications
• Moderate to severe acute respiratory distress syndrome (ARDS)
• CytoSorb therapy indicated by the attending medical team preferably within the first 24 hours, but no later than 48 hours after intubation
• Informed consent for data collection

Exclusion Criteria:

• Unlikely survival for 24 hours according to the attending physician
• Acute onset of hemato-oncological illness
• Patient already on ECMO
• Immunosuppression: on chronic systemic steroid therapy (>10 mg prednisolon/day); immunosuppressive agents (i.e.: methotrexate, azathioprine, cyclosporin, tacrolimus, cyclophosphamide)
• Patients with transplanted vital organs
• Thrombocytopenia (<20,000/uL)

All adult patients admitted to ICUs requiring mechanical ventilation with proven COVID-19 infection and treated with CytoSorb.