Thoracentesis aspiration should not exceed 600 ml for the first time, and the subsequent puncture volume should not exceed 1000 ml per day, otherwise, the patient will develop diplopia pulmonary edema. Patients will experience chest tightness, shortness of breath, and in severe cases, pink foamy sputum, and this phenomenon of respiratory and circulatory failure, which can be life-threatening in severe cases. Therefore, thoracentesis is also a very important medical operation and must be performed in strict accordance with the operating instructions. In addition, it is important to communicate with the patient before the thoracentesis, telling him what may happen during the thoracentesis and the measures to be taken to avoid the patient’s psychological tension that may cause a pleural reaction or a severe case of diplomatic pulmonary edema.