The judgment of cardiac arrest is based on the following: 1. Loss of consciousness: the call is not answered and confusion or coma occurs. The method of judgment is to pat the patient’s shoulder with both hands, shout and see if the patient responds; 2. Touch the aorta: touch the carotid artery pulsation 2-3cm next to the laryngeal node, if the carotid artery pulsation disappears, cardiac arrest can be judged; 3. Judgment of breathing: press the ear against the patient’s nostrils to determine whether there is airflow. Comprehensive above, once cardiac arrest occurs, you should first call for help, and call 120 at the same time, and quickly administer CPR to the patient.