Pleural effusion of about 1000ml needs to be pumped. Pleural effusion is generally divided into a small amount of pleural effusion, that is, about 500 ml of pleural effusion, called a small amount of pleural effusion, when the angle of the rib septum can be blunted from the chest X-ray. A moderate amount of pleural effusion is around 1000ml, and generally speaking, the high-density shadow of pleural effusion reaches the hilum on the chest film, which is about 1500ml or less. A large amount of pleural effusion is a pleural effusion of more than 1500 ml, and the dense shadow can be seen on the chest film beyond the lung hilum, which should be treated by closed chest drainage. Generally a moderate to large amount of pleural effusion requires closed drainage of the chest cavity.