The purpose of this study was to compare the efficacy and safety of nafamostat mesylate and unfractionated heparin during ECMO anticoagulation in critically ill patients.

During ECMO treatment, nafamostat mesylate and unfractionated heparin were randomly administered for continuous anticoagulation, respectively, and the incidence of bleeding and thrombotic complications during anticoagulation was compared between the two groups.

Inclusion Criteria:

• Patients aged >= 18 and <= 80 years;
• Successfully established ECMO (VA/VV) treatment by percutaneous puncture due to cardiogenic shock or respiratory failure;
• Anticoagulation required during ECMO treatment; Before the establishment of ECMO, the APTT test value was within the normal range, and the platelets were not less than 80G/L;
• Within 48 hours of ECMO establishment, APTT test results were between 1 and 1.75 times the upper limit of normal, PLT>80 G/L, and no serious bleeding and thrombosis;
• Sign the informed consent.

Exclusion Criteria:

• Pregnant;
• Bleeding risk or active bleeding;
• Pre-existing diseases requiring long-term anticoagulation before ECMO: pulmonary embolism, deep vein thrombosis, intraventricular thrombosis, atrial fibrillation, etc.;
• Long-term use of anticoagulants before ECMO;
• Antiplatelet drugs were used before ECMO;
• Allergy to heparin, nafamostat mesylate;
• Repeated puncture at the same site for more than 3 times;
• Expected ECMO treatment time < 3 days;
• Patients with an expected survival period of less than 48 hours;
• Patients undergoing extracorporeal cardiopulmonary resuscitation;
• Burn patients; Blood purification treatment using polyacrylonitrile membrane filter;
• Heterozygous ECMO mode or ECMO therapy solely for CO2 removal;
• Other reasons that the investigator considers inappropriate for inclusion;