Improperly performed CPR can result in the following complications: first, rib fractures, sternal fractures, and endochondral injuries, resulting in chest wall instability. Second, is bleeding lung injury, pneumothorax, hemothorax, subcutaneous emphysema. Third, the damage of internal organs, such as liver, spleen, kidney or pancreas. Fourth, injury to the cardiovascular system. Mainly pericardial tamponade occurs, pacemaker or prosthetic valve damage or detachment, arrhythmia, ventricular fibrillation. Fifth, embolism is mainly thrombus, fat embolism and so on. Sixth, gastric reflux causing breathlessness or suffocation.