Extrathoracic cardiac compressions are a first aid method to restore the beating of a heart that has stopped beating from outside the body. Operation steps are as follows: 1, the patient lying on his back on a hard board or the ground. 2, compression position: the rescuer standing or kneeling on the side of the patient (left or right side can be), the root of the palm of the hand on the lower 1/3 of the patient’s sternum, the two hands overlapping, fingers straight or cross interlocked, stick wrist up. 3, compression method: the rescuer leaned forward, hip joint as a fulcrum, arms straight, shoulders directly above the patient’s sternum, by the weight of their own body, with the palm root force downward vertical pressure of about 4-5 cm, and then relaxed, so that the thorax popped up on its own, the time to press and release must be equal. However, the palm root should not be lifted off the chest wall to avoid changing the correct position of the compression. 4, compression frequency: 100 times per minute, the rhythm should be uniform. Artificial respiration and chest cardiac compressions must be alternated. 5, compressions and blowing ratio: compressions 15 times, blowing 2 times for 1 cycle, 15 seconds to complete. Compressions should be observed when the patient’s reaction and facial color.