Inclusion Criteria:

• Adult patients (>18y)
• Cardiac arrest (in-hospital or out-of-hospital) with sustained ROSC (> 30 minutes) admitted to the ICU
• Post-resuscitation shock defined as arterial hypotension (SAP < 90 mmHg or MAP < 65 mmHg) unresponsive to adequate fluid loading, which occurred within the first 24 hours after ROSC and requiring norepinephrine/epinephrine continuous infusion at a dose greater or equal to 0.2µg/kg/min for at least 3 hours
• A maximal delay between the start of norepinephrine infusion and randomization of 9 hours
• Informed written consent of the patient or a legally authorized close relative.

Exclusion Criteria:

• Evidence for a traumatic or a neurological cause of cardiac arrest
• Shock due to uncontrolled haemorrhage
• Previously known adrenal insufficiency
• Limitation of life-sustaining therapies
• Ongoing treatment by any steroids, whatever the dose
• Ongoing extra-corporeal circulatory assistance
• Gastrointestinal bleeding in the past 6 weeks
• Pregnant or breastfeeding women
• Participation in another interventional study involving human participants or being in the exclusion period at the end of a previous study involving human participants, if applicable
• Hypersensitivity to arginin-vasopressin and to its excipients
• Hypersensitivity to hydrocortisone and to its excipients
• Legal protection (i.e. incompetence to provide consent, guardianship, curator or incarceration)
• No affiliation with the French health care system.