 Therapeutic hypothermia is a therapy that involves a controlled lowering of the body temperature and then maintenance of this lower temperature for a period of time. The treatment may result in reduced brain injury. Therapeutic hypothermia has been successfully used in adults who experience cardiac arrest to improve survival rates and health outcomes, and it has also been studied in newborn infants who have suffered from perinatal asphyxia. The purpose of this study is to evaluate the efficacy of therapeutic hypothermia at improving survival rates and reducing brain injury in infants and children who experience cardiac arrest while out of the hospital. 