Steps of external chest cardiac compressions: first of all, the patient should be placed on a hard bed or the ground, not a soft bed; secondly, the correct choice of compression sites, such as adult males are located at the midpoint of the line between the two nipples; then compressions, to be smooth, regular, fast and strong, not impact compressions, violent pressure; should also pay attention to the depth of compressions, compression frequency, the depth of compressions for adults is 5-6cm, the frequency of 100 -120 times / min; artificial respiration steps, in accordance with CPR 30:2.