Finding the Optimal Cooling tempeRature After Out-of-HoSpiTal Cardiac Arrest

Inclusion Criteria: * Signed informed consent (obtained from their legal representative) * 18 years of age or older and less than 80 years old. * Witnessed OHCA of presumed cardiac cause * Sustained ROSC (when chest compressions have not been required for 20 consecutive minutes and signs of circulation persist) * Initial shockable cardiac rhythm (documented by ECG or AED) * Interval from collapse to advance life support \< 20 minutes * Interval from collapse to ROSC \< 60 minutes * Lack of meaningful response to verbal commands upon arrival to hospital after suffering non-traumatic cardiac arrest in an out-of-hospital setting * Systolic blood pressure of \>90 maintained for a least 30 minutes post-ROSC without pressors, or with a stable dose of pressors Exclusion Criteria: * Traumatic cardiac arrest * Toxicological etiology * Known or suspected pregnancy * Do Not Attempt to Resuscitate order in force * Unwitnessed arrest * In-Hospital arrest * Anatomy, previous surgery or disease state contraindicating femoral venous access * Received neuromuscular blocking agents prior to assessing level of consciousness following ROSC * Neurological evaluation insufficient/incomplete after ROSC but prior to randomization. * Body core temperature \< 34ºC at randomization * Current Inferior Vena Cava (IVC) filter * Known history of acute neurological illness or severe functional disabilities prior to arrest (e.g., seizures, traumatic brain injury, increased intracranial pressures, intra-ce…