Overview of pulmonary artery embolism: Acute pulmonary artery thromboembolism is an acute pulmonary artery blood circulation disorder caused by blockage of the pulmonary vascular bed together with dislodged or free thrombus in the systemic venous system and right heart lumen, with the first manifestation of hypoxemia. It is a clinicopathophysiological syndrome of pulmonary circulation obstruction caused by endogenous or exogenous emboli blocking the pulmonary artery or its branches, and pulmonary hemorrhage or necrosis occurs is called pulmonary infarction. Due to the different size, shape, and nature of thrombus embolus, the scope, degree and time of blockage of pulmonary vascular bed, the clinical manifestations are varied, small pulmonary embolism or embolism of small vascular bed area, can be asymptomatic or mild symptoms, larger pulmonary embolism common clinical manifestations include severe dyspnea, increased respiration, chest pain, cyanosis, hypoxemia and even syncope, acute morbidity, misdiagnosis and death rate. The morbidity, misdiagnosis and mortality rate in the acute phase are quite high, with 11% sudden death and 32% total mortality within one hour of onset. Its important clinical significance is: high incidence, second only to coronary heart disease hypertension among cardiovascular diseases; easy to miss and misdiagnosis, clinicians are not vigilant to pulmonary embolism, the correct diagnosis rate is low, the rate of missed diagnosis is up to 80%; untreated mortality can be as high as 20%-30%, the mortality rate accounts for the third cause of death, after tumor and myocardial infarction; clear diagnosis and active treatment mortality rate can be significantly reduced, the mortality rate can be reduced. The mortality rate can be significantly reduced to 2%-8% with clear diagnosis and active treatment. It is one of the most important health care problems at home and abroad and has attracted much attention. Pulmonary embolism is a common cardiovascular disease. It has the following characteristics: 1. high incidence – second only to coronary heart disease and hypertension among cardiovascular diseases; 2. easy to miss and misdiagnosis – the vigilance of pulmonary embolism in China is not high, the correct diagnosis rate is low, and the missing rate is more than 80%; 3. high mortality without treatment – it can be as high as 20%-30%, and the mortality rate is the third cause of death, after tumor and myocardial infarction; 4. clear diagnosis and after The mortality rate decreases significantly in those who are diagnosed and treated – it can be reduced to 2-8%.