Safety and Efficacy Evaluation of CO2 Removal in Combination With Continuous Veno-Venous Hemodialysis/Hemodiafiltration Therapy

Inclusion Criteria: * Informed consent signed and dated by the investigator; and: 1. if patient is able to give consent: by the study patient 2. if patient is unable to give consent: by the legal representative or 3. if an emergency situation is determined: by an independent consultant physician * Minimum age of 18 years Study-specific: * Body weight greater than 40 kg * Acute Kidney Injury (AKI) with clinical indication for CRRT * Hypercapnia with indication for ECCO2R: (paCO2 ≥ 55 mmHg at given best possible protective ventilation parameters: Guiding parameters: tidal volume = 6 ml/kg PBW, PEEP to be adjusted according to the FiO2 1, driving pressure \< 15 cmH2O, max. inspiratory pressure \< 30 cmH2O or TV\<=5 ml/kg when max. inspiratory pressure\< 30 cmH2O cannot be held) * Vascular access and Shaldon catheter allowing blood flow of 100 ml/min to 500 ml/min * Arterial line in place, allowing blood sampling * Estimated life expectancy greater than 3 days Exclusion Criteria: * In case of female patients: pregnancy or lactation period (if patient is ≥ 55 years old or have been surgically sterilized, a negative pregnancy test is not required) * Participation in an interventional clinical study during the preceding 72 hours * Previous participation in the same study Study-specific * Severe ARDS (Berlin definition): PaO2/FiO2 \< 100 mmHg * Intracerebral haemorrhage * Intracranial hypertension * Acute myocardial infarction * Hypersensitivity to heparin or known history of heparin induced thrombocytopenia (HIT Type II), if heparin is used as anticoagulant * severe liver insufficiency or fulminant hepatic failure * Uncontrolled bleeding and coagulation disorders, thrombocytopenia \< 75000µL * Liver cirrhosis CHILD Pugh Classification \> A * BMI \> 40 kg/m² * Decision to limit therapeutic interventions