Diffuse pulmonary arteriovenous fistula is a congenital disease of the pulmonary vasculature in which the blood flows back to the heart without going through the alveoli. Diffuse pulmonary arteriovenous fistula is a congenital disease of the pulmonary vasculature, in which there is abnormal traffic between the pulmonary arteries and veins, and blood flows back to the heart without passing through the alveoli, with insufficient oxygenation of the blood, and intrapulmonary shunts, which are often the cause of acute respiratory distress syndrome. If left untreated, the patient may experience an increase in the number of abnormal channels, causing hypoxia, ischemia, and other symptoms, which gradually worsen. Once formed, arteriovenous fistulas are difficult to recover on their own and usually require surgical treatment to close the fistula by repairing the arteriovenous fistula and repairing the vascular fissure. If the patient has a diffuse pulmonary arteriovenous fistula, it should be treated promptly.