After cardiac arrest, the best time to resuscitate is within four minutes, more than four minutes of oxygen deprivation will cause irreversible damage to cortical cells, once you find cardiac arrest, you should first learn three steps: first, call to the surrounding people as much as possible, immediately call 120. second, if necessary, also artificial respiration, the main purpose of this is to ensure that the patient’s brain and important organs of the heart, can The blood supply in a gradual manner. Third, electric shock, if there is no defibrillator, the patient can be given two compressions on the chest, followed by artificial respiration until the ambulance arrives. The mortality rate of cardiac arrest is high, and for every minute of delay, the patient’s survival rate decreases by 10%. After five minutes of prime time, the patient’s survival rate has dropped to less than 30%, by which time it is very difficult to save the patient.