Early WAKE-up Predictors After Out-of-Hospital Cardiac Arrest

Inclusion Criteria: * Age ≥18 years * OHCA of presumed cardiac cause * Sustained ROSC, defined as persistent signs of circulation and no need for chest compressions or mechanical circulatory support for 20 minutes * Unconsciousness (GCS \<9) (patients not able to obey verbal commands) after sustained ROSC at the time of randomization Exclusion Criteria: * Females of childbearing potential if pregnancy is suspected (unless a negative HCG test can rule out pregnancy within the inclusion window) * Known bleeding diathesis (medically induced coagulopathy (e.g. warfarin, NOAC, clopidogrel) does not exclude the patient) * Suspected or confirmed acute intracranial bleeding * Suspected or confirmed acute stroke * Unwitnessed asystole * Known limitations in therapy and Do Not Resuscitate-order * Known disease making 180 days survival unlikely * Known pre-arrest CPC 3 or 4 functional status * \>3 hours (180 minutes) from ROSC to screening * Systolic blood pressure \<80 mm Hg despite fluid loading/vasopressor and/or inotropic medication (If the systolic blood pressure is recovering during the inclusion window of 180 minutes the patient may be included) * Use of intra-aortic balloon pump/axial flow device/ECMO (If the patient is weaned and the device is removed during the inclusion window of 180 minutes the patient may be included) * Temperature on admission \<30°C * Known allergy for dexamethasone or olanzapine * Ongoing (within 48 h) treatment with olanzapine or dexamethasone * Known back or hip condition that precluded the patients from being positioned with backrest from 0 to 45-degree angle * Known or suspected Long QT Syndrome (LQTS) * Known active fungal disease. Localized skin lesions do not exclude patients from inclusion * Estimated body weight \<45kg