In severe lung or heart disease, ExtraCorporeal Membrane Oxygenation (ECMO) may be used temporarily and can be responsible for major haemorrhagic complications. Thrombocytopenia and possibly thrombopathy promote bleeding. The primary objective is to characterize platelet dysfunction by aggregometry tests over time. Secondarily, investigators seek a correlation between haemorrhagic complications at day 10 and markers of platelet action and dysfunction; also, with the level of anticoagulation and inflammation by biomarkers.

Despite the frequency of thrombocytopenia in patients on VV-ECMO and its associated haemorrhagic consequences, its predictive factors are still poorly described. Furthermore, studies suggest the presence of thrombopathy in patients on ECMO, but they are scarce and based on a heterogeneous population with a small sample size, or with vent-arterial (VA) ECMO, mainly after cardiac surgery exposed to a different extracorporeal circulation. The factors responsible for this thrombopathy and its repercussions are currently unknown. In contrast to previous studies that focused on platelet functions in patients on ECMO, our study will be the first to analyse specialized platelet functions and thrombo-inflammation in a cohort only with VV-ECMO excluding cardiac surgery patients at risk of thrombopathy. This work will provide, for the first time, a comprehensive view of the patient on VV-ECMO, ranging from clinical characteristics to the study of platelet activation and functions and thrombo-inflammation analysis and also integrating biological data and ECMO characteristics, all over time. The procedure will involve collecting blood samples from the patient on VV-ECMO and platelet aggregation tests will be performed, along with measurements of platelet activation markers and a search for leuko-platelet aggregates. Investigators will evaluate the clinical-biological impact by searching for blood hemolysis, the level of inflammation, coagulopathy and hemorrhagic complications during VV-ECMO support. The patient's clinical characteristics will be analysed until their discharge from the intensive care unit. Clinical, biological, ECMO, and specialized haemostasis data will be studied to achieve the study objectives.

Inclusion Criteria:

• Adults aged ≥ 18 years
• No objection to participation in the study, obtained from a relative or trusted person; if no relative is available, inclusion under emergency procedure (pending patient or relative non-opposition)
• Patients requiring admission to the general intensive care unit of Hôpital Rangueil for venovenous ECMO
• Equipped with an arterial catheter for blood sampling
• Ability to undergo the 4 blood draws relevant to the study
• Receiving therapeutic anticoagulation with unfractionated heparin
• Enrolled in a social security program or equivalent
• No measures for Limitation and Withdrawal of Therapy have been implemented

Exclusion Criteria:

• Minors
• Patients under court-appointed guardianship or conservatorship
• Pregnant or breastfeeding women
• Hematological disease (leukemia, lymphoma) or constitutional thrombocytopenia
• Platelet transfusion within 7 days prior to enrollment
• Indication for immediate emergency ECMO preventing blood sampling before placement
• Post-cardiotomy
• Patient on antiplatelet therapy
• Severe thrombocytopenia <50 G/L
• Other invasive mechanical support such as Impella®, intra-aortic balloon pump, or Left Ventricular Assist Device (LVAD)

The study population will be selected from adult patients requiring venovenous ECMO support and admitted to the general intensive care unit of Hôpital Rangueil (Toulouse University Hospital), a regional referral center for ECMO in Occitanie West. Patients may be transferred from other hospitals in the region or directly managed at Hôpital Rangueil following ECMO implantation.