CPR girls press on the lower part of the sternum. The main points of CPR are as follows: compression position, compression depth, compression frequency, artificial respiration. 1. Pressure position: the lower part of the sternum. 2. Depth of compression: no less than 5cm for adults, about 5cm for children, and about 4cm for infants. 3. Pressure frequency: 100 to 120 times per minute. The ratio of chest compressions to artificial respiration is 30:2, so two artificial respirations are performed for 30 compressions, and the time for 30 compressions is kept at 15 to 18 seconds. 4. Artificial respiration: lift the patient’s head upward, press the patient’s forehead, lift the patient’s jaw, wrap the mouth around the patient’s mouth, and blow on the patient twice, once for 1 second. When artificial respiration is performed after compressions are performed again on the patient, this time should not exceed 10 seconds. Cardiopulmonary resuscitation (CPR) is a first-aid measure for patients with cardiac arrest, who are unresponsive and unable to breathe, and require the rescuer to perform chest compressions and artificial respiration on the patient. Family members of cardiac arrest patients are advised to call 120 for first aid.