A cluster randomized trial of duration of cooling in therapeutic hypothermia after resuscitation for cardiac arrest

INTERVENTION: Targeted cooling duration 12‐24 hours in Therapeutic hypothermia Targeted cooling duration 36 hours in Therapeutic hypothermia CONDITION: Cardiac Arrest PRIMARY OUTCOME: Incidence proportion of complications within 1 month.; Definition of complications; infection, hemorrhage, Arrhythmia, decreasing blood pressure, shivering, convulsion and MACE(Major Adverse Cardiovascular Events) The evaluation of primary outcome is under blinded groups by Data Safety Monitoring Board SECONDARY OUTCOME: 1) Proportion of death (within 24 hours, 7 days, 1 months, 3 months, at discharge); 2)Proportion of good neurological outcome (CPC: Cerebral Performance Categories) (within 24 hours, 7 days, 1 months, 3 months, at discharge); 3) Mortaliry rate; 4) Incidence rate of complications INCLUSION CRITERIA: 1)Cardiac arrest 2)Stability of circulatory dynamics after ROSC(Return of spontaneous circulation) [including assisted with drug or auxiliary circulating pump] 3)Comatose state after ROSC 4)Adaptability status of therapeutic Hypothermia