Low-flow Extracorporeal Carbon Dioxide Removal in COVID-19-associated Acute Respiratory Distress Syndrome

Inclusion Criteria: * mild-to-moderate ARDS according to the Berlin definition * lung-protective ventilation with positive end-expiratory pressure (PEEP) \> 5 cm of water on mechanical ventilation expected to last \> 24 h * hypercapnia \<80 mmHg * bilateral opacities on chest imaging Exclusion Criteria: * age \< 18 years * pregnancy * patients with decompensated heart failure or acute coronary syndrome * respiratory acidosis with persistent partial pressure of blood carbon dioxide (PCO2) levels \>80 mmHg * acute brain injury * severe liver insufficiency (Child-Pugh scores \> 7) or fulminant hepatic failure * decision to limit therapeutic interventions * catheter access to femoral vein or jugular vein impossible * pneumothorax