To determine whether a patient needs chest compressions: First, determine whether the patient has loss of consciousness, respiratory arrest, or loss of aortic pulsation. If these three conditions are met within ten seconds, start chest compressions immediately. The first step is to assess the safety of the environment and place the patient on a hard bed or on a flat surface to fully expose the patient’s thorax. The position of compression is the intersection of the middle and lower third of the sternum with the midline, and the compression technique is to press the interphalangeal area of one hand against the patient’s chest wall, with the five fingers up; the other hand is crossed and overlapped on top of the operating hand, and the frequency of compression is 100-120 times per minute, and the depth of compression is 5-6 cm. There should be no bending of the elbow joint.