Cardiopulmonary resuscitation (CPR) is an emergency rescue technique to maintain blood circulation and oxygen supply in the case of cardiac arrest or respiratory arrest. The purpose of cardiopulmonary resuscitation is to restore the function of the heart and lungs as soon as possible, so as to avoid brain damage and death caused by hypoxia.

The correct method of cardiopulmonary resuscitation includes the following steps:

1. Check the environmental safety: Before starting cardiopulmonary resuscitation, you must ensure the environmental safety to avoid injury or danger.

2. Check consciousness and breathing: check whether the patient is conscious and breathing. If the patient is unconscious and breathing, start cardiopulmonary resuscitation immediately.

Call an ambulance: Before starting CPR, you must call an ambulance immediately so that professional medical personnel can arrive in time.

4. Start chest compressions: During cardiopulmonary resuscitation, chest compressions must be performed to help the heart pump blood. When pressing, you must put your hand in the center above the sternum, and then press down at least 5 cm. Press 100 to 120 times per minute.

5. Perform artificial respiration: When performing chest compressions, perform artificial respiration. Tilt the patient's head backwards, then put his mouth close to the patient's mouth and blow at least 1 sec. Perform artificial respiration twice after every 20 chest compressions.

6. Continuous CPR: Before the ambulance arrives, CPR must be continued to ensure that the heart and lungs get enough oxygen and blood.

It should be noted that CPR is an emergency rescue technique and should only be used when necessary. If the patient is conscious and breathing, CPR should not be performed. In addition, the effect of CPR depends on the accuracy and speed of operation, so it must be carried out under the guidance of professionally trained personnel.