Closed chest drainage is very important to maintain the negative pressure in the chest cavity and drain the gas and fluid in the pleural cavity. In order to maintain the sterility of the closed chest drainage tube, the chest drainage tube and drainage bottle need to be replaced regularly. The following matters should be noted when replacing the drainage bottle and drainage tube: First, the drainage tube should be double-clamped to prevent gas and fluid from entering the chest cavity. Second, the replacement of drainage bottles and drainage tubes must be kept sterile. Third, the drainage tube must be kept in the drainage bottle, more than 3-4 cm below the surface of the liquid. Fourth, observe the drainage tube after reinserting it into the drainage bottle, whether the drainage tube is folded, twisted, etc. Observe whether there are fluctuations in the water column, and whether there is any gas or liquid discharge from the chest cavity. V. When moving as well as moving, keep the distance of the drainage bottle from the chest cavity greater than 60-100cm. vi. When replacing the drainage bottle, observe whether the incision dressing is oozing and needs to be replaced, keep the incision sterile, keep the interface of the drainage tube and other parts firmly connected, and disinfect regularly.