Clinical Study of the LRS ThermoSuit™ System in Post Arrest Patients With Intravenous Infusion of Magnesium Sulfate

Inclusion Criteria: * Cardiac arrest prior to or during hospital admission, with restoration/return of spontaneous circulation (ROSC). * Estimated or known age \> 18 years. * Intubation, ventilation and placement of esophageal temperature probe. * Persistent neurologic dysfunction i.e. comatose upon enrollment \[GCS ≤ 8\]. Exclusion Criteria: * Height greater than 188 cm. * Elbow-to-elbow width greater than 60 cm (as measured above the supine patient). * Core temperature less than 35°C after ROSC (as measured in the esophagus). * Comatose state before the cardiac arrest due to the administration of drugs that depress the central nervous system. * Known pregnancy. * Known terminal illness that preceded the arrest. * Known enrollment in another study of a device, drug, or biologic. * Major trauma or other co-morbidity requiring urgent surgery. * \> 4 hours since return of spontaneous circulation. * Severe coagulopathy (with active bleeding). * Hemodynamic instability despite vasopressors (SBP \< 90 mmHg or MAP \< 60 mmHg for \> 30 minutes after ROSC and before enrollment). * Bradycardia (HR\<60/min) * Allergy against MgSO4 * AV-block * Myasthenia gravis * Known terminal renal insufficiency (creatinine-clearance \< 20ml/min) * Severe myocardial dysfunction (EF\<25%) * Chronic digitalis therapy