Pleural fluid extraction is relatively safe, the chance of complications is small, mainly the following: 1, pneumothorax: due to puncture of the dirty layer of the pleura caused by gas leakage from the lungs, a small amount of pneumothorax to take oxygen, bed rest, a large number of pneumothorax need to puncture suction gas; 2, pleural reaction: common in younger patients, due to nervousness appears sweating, chest tightness, panic and other symptoms, the operation should be immediately stopped, the patient is asked to bed rest, oxygen; 3, subcutaneous hematoma: a large number of subcutaneous blood vessels due to improper operation appear swelling, pain and other symptoms, 2-3 days after absorption, it is recommended to ask for surgical treatment; 4, pulmonary edema: a large number of patients with pleural fluid can be absorbed. Subcutaneous hematoma: swelling, pain and other symptoms appear due to improper operation of punctured subcutaneous vessels, which can be absorbed after 2-3 days. It is recommended to ask for surgical treatment for larger hematoma; 4. Pulmonary edema: patients with large amount of pleural effusion extract too much fluid at one time, which causes the lungs to expand too fast and capillary permeability in the lungs to increase, resulting in fluid inflow into the lungs causing chest tightness, shortness of breath and other symptoms.