The aim of this observational study is to assess whether myoglobin removal with CytoSorb® ameliorates endothelial damage in severe rhabdomyolysis patients who are admitted to the intensive care unit. The primary objective of the study is:

- Does myoglobin removal with CytoSorb® reduces glycocalyx degradation markers?

Patients with severe rhabdomyolysis will receive the intervention and blood samples will be obtained in regular intervals.

Rhabdomyolysis is characterized by destruction of muscle by various causes and is diagnosed by increased creatine kinase concentrations in the blood. Myoglobin released into the blood may cause acute kidney injury in up to half of these patients. The mortality caused by severe rhabdomyolysis is also high (32%). Extracorporeal modalities, such as CytoSorb (CS) can effectively eliminate the myoglobin from the bloodstream.

In addition to ischemic and inflammatory damage, myoglobin also causes direct endothelial cell injury. Degradation of the endothelial glycocalyx layer can be assessed by several biomarkers such as Syndecan-1, Heparan sulfate, cadherin

However, it is not fully known whether myoglobin elimination improves the outcomes or it is irrelevant of the outcome.

The investigator hypothesized that myoglobin elimination with CS alleviates the damage inflicted upon the endothelium and may have a role in improving patient outcomes in severe rhabdomyolysis.

Inclusion Criteria:

• Patients with Creatine Kinase > 5000 IU/L.
• Myoglobin results can be obtained only after 5 working days after sampling in our center, therefore it cannot be used as an inclusion criteria.
• GFR below 40 ml/min.

Exclusion Criteria:

• High dose vasopressor requirement
• Not expected to survive > 24 h
• Lack of consent to participate

18 years and older patients who need cytosorb therapy due to rhadomyolysis