An extracorporeal circuit (1) for removing CO2 from blood comprising a blood taking line (2) for taking blood from the patient, an oxygenation assembly (4) and a blood reintroduction line (5) for re-introducing blood into the patient. The oxygenation assembly (4) comprises an oxygenator (9), a dialyzer (6) arranged upstream of the oxygenator (9), a circulation circuit (7) for the circulation of a dialyzer bath connected to the dialyzer (6) and an acidifier (10) arranged to introduce an acid substance into the circulation circuit (7) for circulation of the dialyzer bath.
