The site of chest compressions for adults is located in the lower 1/2 of the sternum. The patient must be lying down with a wooden board on the back or lying flat on the floor while the operator is standing or kneeling on the patient’s side, and the site of chest compressions is in the lower 1/2 of the sternum. The thoracic cardiac compressions should be rapid and forceful, and the thorax should be completely reset after each compression, if the thorax cannot be completely reset, it can lead to an increase in intrathoracic pressure and reduce the perfusion of coronary arteries and brain. So repeatedly, the heart drains blood when pressed and refills when released, forming an artificial circulation, so that the compressions are effective.