Mean Arterial Pressure After Out-of-hospital Cardiac Arrest

Out-of-hospital cardiac arrest is a public health problem for which overall survival is below 10%. Post-cardiac arrest syndrome is the principal cause of death in intensive care units (ICU), due to refractory shock or brain injuries secondary to anoxia. Brain anoxia is responsible for severe neurological sequelae that may be aggravated by cerebral hypoperfusion during the first few hours after the return of spontaneous circulation. Current recommendations are to ensure that arterial blood pressure is sufficient for the perfusion of organs, but no minimum threshold mean arterial pressure (MAP) has been defined. In practice, most teams target a MAP of at least 65 mmHg. Several observational studies have shown a correlation between MAP and neurological prognosis, patients with a higher initial MAP having a better outcome. Recent pilot studies have demonstrated the feasibility of increasing the target MAP after cardiac arrest, but conflicting results have been obtained concerning patient prognosis. These findings may be explained by changes to the autoregulation of the brain after cardiac arrest, with a shift of the curve towards the right, or its abolition. Cerebral blood flow is dependent on MAP, and a target MAP of 65 mmHg for these patients may result in insufficient brain perfusion. Conversely, a too high MAP might cause brain lesions due to vasogenic edema, hemorrhagic complications or excess perfusion in conditions of diminished brain metabolism. An interventional study is required to evaluate the effect of increasing MAP on neurofunctional outcome after cardiac arrest. Given the data available for brain autoregulation, the correlation between MAP and prognosis, and the risks theoretically associated with a higher MAP, investigator plans to compare a standard threshold of MAP (≥ 65 mmHg) with a high threshold of MAP (≥ 90 mmHg). Investigator hypothesizes that a high MAP within the first 24 hours after cardiac arrest will improve neurofunctional outcome.


Eligibility Criteria:
Inclusion Criteria:

* Admission to ICU following an out-of-hospital cardiac arrest with an initially shockable or non-shockable rhythm ;
* Sustained ROSC defined as 20 minutes with signs of circulation without the need for chest compressions;
* Under invasive mechanical ventilation for coma, defined as a Glasgow score ≤ 8/15;
* Consent from a relative or of a procedure for emergency inclusion.

Exclusion Criteria:

* Age \< 18 years ;
* In-hospital cardiac arrest (first cardiac arrest);
* Unwitnessed CA with initial rhythm of asystole
* Delay between ROSC and attempting randomisation \> 6 hours ;
* Cardiac arrest in a context of multiple trauma ;
* Cardiac arrest in a context of hemorrhagic shock or severe hemorrhage necessitating hemostasis (surgery or radiological or endoscopic hemostasis) ;
* Cardiac arrest secondary to an acute brain disease (ischemic or hemorrhagic stroke, subarachnoid hemorrhage, severe traumatic brain injury) ;
* Refractory shock :

Defined as a MAP \< 65 mmHg for more than one hour on norepinephrine or epinephrine at a dose \> 1 µg/kg/min despite adequate fluid resuscitation ;

* Extracorporeal circulatory support prior to inclusion;
* Known allergy to norepinephrine or to any of its excipients;
* Decision to limit care before inclusion ;
* Modified Rankin score of 4 or 5 before cardiac arrest ;
* Inclusion in another interventional study in which the principal endpoint is neurological prognosis ;
* Pregnancy or breast feeding ;
* Adult patient deprived of freedom or under legal protection (patients under guardianship or curatorship) (article L1121-6 of the French Health Code) ;
* Non-French speaking;
* Patient already included in this trial ;
* Absence of social security cover.