Closed thoracic drainage is one of the operations frequently performed in many departments, including cardiac surgery, thoracic surgery and respiratory medicine. Closed thoracic drainage is widely used, mainly in the following areas: first, chest trauma, mainly in the chest after trauma more obvious pleural fluid, pneumonia; second, pneumothorax, mainly in the lung more serious compression of the pneumothorax or tension pneumothorax; third, infection in the thoracic cavity and tumor caused by the accumulation of fluid and gas in the thoracic cavity more, need to continue to drain; fourth, other cases, such as heart or After thoracic surgery, routine placement of closed chest drainage can drain postoperative blood and gas accumulation, reduce complications and promote early recovery of patients.