Intravenous injection of small amounts of air is generally not fatal. Intravenous injection of large amounts of air may result in air embolism, leading to coronary artery embolism, cerebrovascular embolism, pulmonary embolism and other conditions that may be fatal. 1. Coronary artery embolism: a large amount of air into the coronary arteries of the heart will lead to coronary artery embolism, resulting in acute myocardial infarction symptoms, serious patients will experience arrhythmia leading to cardiac arrest and death. 2. Cerebrovascular embolism: a large amount of air into the cerebral blood vessels can lead to acute cerebral embolism, which can lead to coma or respiratory failure in severe cases, causing patients to asphyxiate and then die. 3. Pulmonary embolism: a large amount of air into the lungs will affect the respiratory function, resulting in respiratory distress gradually developed into respiratory failure, so that the whole body is hypoxic and ischemic symptoms, which in turn leads to death. Air injected into the vein is usually due to intravenous infusion, in the process of infusion, we should pay attention to observe the amount of remaining fluid, found that the intravenous infusion of air, should promptly notify the doctor for treatment.