Open hypodermic aspiration generally refers to thoracentesis drainage. Patients with advanced pleural effusion of lung adenocarcinoma may have complications such as pneumothorax and pleural reaction in the process of thoracentesis drainage, but the risk is not high in general. Thoracentesis and drainage can relieve the symptoms caused by pleural effusion in advanced stage of lung adenocarcinoma, but the operation may cause some complications, such as bleeding caused by damaging the blood vessels between ribs in the process of thoracentesis; the patient may also suffer from pleural reaction, which is manifested as tightness in the chest, palpitation, pallor, and so on; and pneumothorax may occur if the puncture breaks the lung tissues in too deep a way. However, thoracentesis and drainage is a common clinical operation, and if the operator operates in a standardized manner and the patient actively cooperates, some complications can generally be avoided, so the risk is not high. Patients with advanced lung adenocarcinoma with pleural effusion who need thoracentesis drainage should actively cooperate with doctors.