Pulmonary embolism mainly includes pulmonary thromboembolism, amniotic fluid embolism, air embolism, fat embolism and other types, among which pulmonary thromboembolism is the most common, some patients with pulmonary embolism may not have obvious clinical manifestations, some patients with pulmonary embolism mainly include the following clinical manifestations: 1, respiratory system: common shortness of breath, dyspnea, etc. Some patients with pulmonary thromboembolism may be accompanied by cyanosis, pulmonary rales or fine wet rales. Some patients with pulmonary thromboembolism may have cyanosis, pulmonary rales or wet rales, and signs of pleural effusion, which are more obvious after activity, and patients with pulmonary embolism may also have chest pain and hemoptysis, but they are generally rare; 2. Circulatory system: tachycardia and blood pressure changes are common, and shock can be caused when blood pressure drops severely; 3. Patients with cerebral hypoxia caused by pulmonary embolism may also have irritability, accompanied by panic, syncope and even near-death feeling; 4. Other manifestations: some patients with pulmonary embolism may also have fever, chills and other systemic signs. The fever condition is mostly low fever, and a few patients may have moderate or high fever above 38℃. Besides, loss of consciousness is the typical symptom in the early stage of air embolism, which may be accompanied by convulsions, hemiparesis and other signs. In contrast, amniotic fluid embolism is common in pregnancy, with a rapid onset and can cause respiratory failure, cardiac arrest or even shock and death at the early stage.