Is Anti-Factor Xa Associated With Outcome in Patients With Critical COVID-19 on Low-Molecular-Weight Heparin? (AntiXCOVID)

All patients with critical COVID-19 and respiratory failure admitted to ICU at Södersjukhuset, Karolinska Sjukhuset and Skånes Universitetssjukhus, in Sweden, between March 1 2020 and May 31 2021 are eligible.

Patients will be included on their first admission to the ICU if admitted more than once. First admission can be replaced by the second one if the first one is considered very short/insignificant compared to the second one. If a patient is transferred from one ICU to another this will be considered the same admission but they will be grouped according to their initial ICU.

Inclusion Criteria:

• Patients with critical COVID-19 and respiratory failure
• Positive SARS-CoV-2 test
• LMWH-effect monitored by aFXa, as a trough or peak value, after at least four doses at a twice daily regime

Exclusion Criteria:

• Diagnosed thromboembolism or major bleeding during their COVID-illness prior to ICU-admission or as a reason or contributing factor for the ICU-admission.
• Transferred to or from an ICU in other hospital/region making data collection regarding baseline data/outcomes not possible