Air embolism is an air embolism that occurs when air enters the blood circulation caused by various factors. The gas that enters the pulmonary vein passes through the left atrium and left ventricle with the blood flow, and finally flows into the arterial branches of the whole body, blocking them and causing ischemia of the corresponding organs, especially the brain and myocardium; in serious cases, the blood flow back to the left heart can be obstructed, causing severe circulatory failure, and the patient can die immediately. Prevention and control measures of air embolism: (1) Check the quality of the infusion set carefully before infusion, exhaust the air in the infusion tube, observe closely during the infusion, and guard the infusion or blood transfusion under pressure to prevent air embolism. (2) Immediately stop the infusion, notify the doctor in time, actively cooperate with the resuscitation, and comfort the patient to reduce the fear. (3) Immediately place the patient in the left lateral position and head-low-foot-high position. (4) High-flow oxygen inhalation. (5) Pump out air through central venous catheter if possible. (6) Closely observe changes in condition.