Dressing change, also known as changing accessories, is used for trauma and surgical wounds, infectious wounds, body surface ulcers and sinus tracts. The operation process of dressing change technology is as follows: 1. When changing the medicine, the movement should be light, the outer layer can be changed by hand, and the inner layer can be changed by sterile toothless pliers. If the dressing is dry and close to the wound, it should be soaked with normal saline before opening. Sterilize the skin around the wound. Suturing the wound is to scrub the skin around the wound from the center to the outside with an alcohol cotton ball. The infected wound after drainage is scrubbed with alcohol cotton ball from the outside to the center, usually 2 ~ 3 times. Be careful not to use alcohol cotton balls to scrub the wound inside. 2. Treatment of the skin around the wound Use a pipe wrench to hold a cotton ball of normal saline and gently lick the wound exudate. Wipe it clean with a few cotton balls. But be careful not to leave cotton balls in the wound. For wounds with secondary infection, special attention should be paid to whether there is any wireless foreign body in the wound, and it should be taken out in time once it is found. 3. Placement of drainage If the wound needs to be drained, the drainage materials such as gauze strips and latex tube should be placed in the lowest position of the wound according to the body position, and the tightness is appropriate, and the end of the drainage material should be exposed outside the wound. 4, bandage fixed with sterile dry gauze cover, adhesive tape fixed. For wounds with large wounds and excessive exudation, a cotton pad can be added. If the tape is not fixed properly, it must be bandaged.