Cerebral lesions are responsible for two thirds of deaths in patients admitted to intensive care following cardiac arrest. Patients with neurological lesions should be the priority target for neuroprotective interventions, which are the cornerstone of post-cardiac arrest care (allowing a reduction in the burden of care for patients without this type of lesion). Furthermore, these interventions must be based on a precise assessment of the severity of these brain lesions: carrying out neuro-protective interventions in patients without brain lesions exposes these patients to unnecessary treatment potentially associated with adverse effects without any possible benefit. However, the early assessment of neurological prognosis, particularly on admission to intensive care, is an area where there is little research and where it is not possible to obtain a precise and reproducible assessment. Several tools can be used to assess this prognosis at an early stage: anamnesis and characteristics of the cardiac arrest and the patient's comorbidities, imaging, electrophysiology and biomarkers.

To assess the predictive value of early biomarker testing in patients resuscitated after cardiac arrest, whatever the cause, the investigators plan to conduct a prospective observational multicentre trial.

It is important to bear in mind that the aim of this study is not to assess the long-term prognosis of patients suffering cardiac arrest in order to take measures to limit or discontinue active therapies, but simply to provide a reliable tool, simple and quick to use, in order to be able to identify a sub-population of patients who should be the subject of preferential neuro-protection measures, and conversely to simplify management (moderate temperature control, early cessation of sedation, early extubation) for patients with no neurological lesions.

Inclusion Criteria:

• Age ≥ 18 years
• Admitted to intensive care with out-of-hospital cardiac arrest
• Comatose on admission (defined by a Glasgow score ≤ 8)
• Informed relative who has consented to the patient's participation in the study or inclusion under emergency procedure if the relative is absent at the time of inclusion

Exclusion Criteria:

• In-hospital cardiac arrest
• Age < 18 years
• Person under guardianship or legal protection
• Prior inclusion in the study

Patients will be included on admission to intensive care.