Emergency CPR is required when the heart stops beating and breathing stops. When you encounter a person on the roadside who has collapsed and is unconscious, you should not start CPR without judgment, because although the person has collapsed, the heartbeat and breathing are not necessarily abnormal. There are many reasons for collapse and unconsciousness, such as seizure, stroke, acute cardiovascular accident, A – S seizure or postural syncope. Generally CPR requires 3 compression cycles and artificial respiration before it is considered a complete rescue process, after a full course of compressions, pay attention to the recovery of respiration and heartbeat, pulse, if the effect is not obvious need to perform timely electric defibrillation therapy.