Unfractionated heparin is most common in the anticoagulation management of V-V ECMO. However, many side effects of unfractionated heparin, such as HIT, antithrombin deficiency, etc seriously affects the prognosis of patients. Argatroban is kind of direct thrombin inhibitors, which could be used used as an alternative anticoagulant of unfractionated heparin when HIT or antithrombin deficiency, etc. At present, there is no power enough evidence for the application of argatroban in V-V ECMO. This study aims to evaluat the safety and effectiveness of argatroban in the anticoagulation management of V-V ECMO compared with unfractionated heparin.

Inclusion Criteria:

• age older than 18 years old; received V-V ECMO because of sevever respiratory failure

Exclusion Criteria:

• anticoagulant contraindications; Confirmed or suspected, or previously diagnosed with heparin induced thrombocytopenia; Cerebral infarction or suspected patients; Patients with severe liver dysfunction; Allergic to heparin or argatroban; hemophilia; Unwilling or unable to complete the study.

Study protocal, statistical analysis plan, informed consent form and clinical study report will be shared.

1 year after the study completed.

Contact PI by email with reasonable reasons.