Cardiac arrest refers to the sudden cessation of heart beating due to various reasons, the disappearance of effective pumping function, and severe hypoxia and ischemia of the whole body. The clinical manifestations are the inability to palpate the large artery pulsation and the disappearance of heart sounds; followed by loss of consciousness, respiratory arrest, and dilated pupils. If not promptly rescued, it may cause death. It is generally believed that dizziness or syncope may occur after 5 to 10 seconds of cardiac arrest, syncope and convulsions may occur after more than 15 seconds, and coma may occur after more than 20 seconds; if the heart stops beating for more than 5 minutes, it can often cause severe brain damage or death, and even if it is restarted, it often leaves sequelae of varying degrees. Therefore, cardiac arrest is the most serious emergency in clinical practice, and active rescue must be carried out every minute.