Since the 1990s, the concept of “chain of survival” has been proposed. The key to maintaining the “chain of survival” is the “golden 4 minutes”, that is, after the accident, the first witness should start to implement CPR within 4 minutes to maintain the patient’s blood circulation and respiratory process to the maximum, and wait for the professional and resuscitation equipment. arrival. Only then will the patient have a chance of survival. First witnesses who wait passively, even in developed countries, cannot guarantee that an ambulance will arrive at the scene within 4-5 minutes. Beyond 4 minutes, the patient may have no hope of survival, and even if resuscitation is successful, the patient may become a vegetable. Therefore, people regard the first 4 minutes of resuscitation as the “golden 4 minutes”. Medical research shows that if there is respiratory and cardiac arrest, the limit of tolerance of human brain cells to oxygen deprivation at room temperature is usually 4 minutes; more than 4-6 minutes, the brain damage is irreversible; more than 8 minutes, the possibility of successful resuscitation is very small; more than 15 minutes, the chance of successful resuscitation is almost 0. Therefore, before the arrival of doctors and resuscitation equipment at the scene, the presence of Therefore, before doctors and resuscitation equipment arrive at the scene, everyone present should be put into the resuscitation process within 4 minutes, in order to maintain the maximum oxygen supply to brain cells and slow down or stop the necrosis of brain cells. In the “golden 4 minutes”, the rescuer should try to lower the patient’s head temperature, using cold water bags, ice packs, etc. placed on the patient’s head, and then do mouth-to-mouth artificial respiration and chest cardiac compressions. Artificial respiration enables oxygen to enter the blood transport, and chest cardiac compressions make the blood with oxygen flow to the whole body, especially the blood with oxygen into the brain tissue, which can maintain the activity of brain cells, thus ensuring human life. This shows the importance of the “golden 4 minutes” to save lives.