Neuroprotective Effect of Remote Ischemic Post-conditioning in Out-of-hospital Cardiac Arrest

Patients admitted to intensive care unit (ICU) following an out-of-hospital cardiac arrest (OHCA) have a high morbidity and mortality rate, primarily due to ischemia-reperfusion (I/R) syndrome leading to anoxic-ischemic brain injury. Despite current recommended advanced life support therapies, no specific treatment or procedure has yet been shown to improve the neurological outcome of such patients.

Remote ischemic post-conditioning (RIPOST) which usually consists of applying brief and repeated cycles of ischemia alternating with reperfusion by inflating and deflating a blood pressure cuff or a pneumatic tourniquet placed around a limb, is a promising strategy to protect organs against I/R injury, including brain. Regarding cardiac arrest, pre-clinical studies have demonstrated an improvement in neurological outcome in animal subjects treated with RIPOST after cardiopulmonary resuscitation.

The aim of our study is to demonstrate the benefit of early RIPOST in OHCA patients in reducing neurological injury and organ failure related to I/R syndrome.

The RIPOST trial is a prospective, single-center, randomized, open-label, parallel group trial.

Patients with inclusion criteria will be randomized in two parallel groups:

* Experimental group: standard of care associated to 3 RIPOST sessions : one within the 4 hours following cardiac arrest, one 12 hours after cardiac arrest and one 24 hours after cardiac arrest. A RIPOST session = four cycles of cuff inflation to 200 mmHg for five minutes and then deflation to 0 mmHg for another five minutes, using an inflatable thigh tourniquet (total duration of the session = 40 minutes).
* Control group: standard of care associated to 3 sham sessions at inclusion, 24, and 48 hours after inclusion. A sham session = application of the thigh tourniquet during 40 minutes without any inflation.

Inclusion duration: 24 months

Patient participation duration: 3 months

Study duration: 27 months

Eligibility Criteria:
Inclusion Criteria:

* Out-of-hospital cardiac arrest with stable return of spontaneous circulation (ROSC \> 20 minutes)
* Patient receiving invasive mechanical ventilation for coma (Glasgow score \< 8)
* Availability of a lower limb without intravenous infusion or tension cuff positioned on it
* Randomization and application of the first session of the tested procedure within 4 hours after ROSC
* Consent of a next-of-kin or inclusion in emergency procedure

Exclusion criteria :

* Age \< 18 y.o or pregnancy
* Patient unable to walk without assistance, unable to support himself properly without assistance, bedridden, incontinent and requiring nursing constant attention and care (corresponding to a mRS equal to 4 or 5)
* Interval between cardiac arrest and ROSC (no flow + low flow) estimated \> 60 minutes
* Unwitnessed cardiac arrest with asystole as first rhythm
* In-hospital cardiac arrest
* Refractory cardiac arrest (no ROSC considered as stable)
* Cardiac arrest from traumatic, hemorrhage, stroke or hanging supposed origin
* Mean arterial pressure \< 65mmHg persisting despite appropriate vascular filling and vasopressor and/or inotropic support
* Active uncontrolled bleeding
* Contraindication or not possible to use a pneumatic tourniquet on none of the two lower limbs (amputations, intravenous infusion positioned on both lower limbs, tourniquet size incompatible with patient morphology)
* Implementation of extracorporeal arteriovenous circulation for refractory cardiac arrest or refractory cardiogenic shock before inclusion
* Patient already included in this study
* Inclusion in another interventional study
* Judicial protection measure
* Patient without French social security