Strictly speaking after the dressing change, the gauze covering the wound should be 16 layers, and the normal gauze, if not opened, needs two pieces of gauze to cover the wound, so as to effectively protect the wound, isolate the wound from the outside environment effectively and prevent bacterial infection of the wound. For clean wound dressing change, it is usually done 3 days after surgery. When changing the dressing, disinfect the wound surface with iodophor twice, and check the wound for redness, swelling, exudation, etc. If not, it can be covered with two pieces of gauze. If the wound is infected, exuding and needs to be drained, the wound is filled with gauze strips inside, and then the layers of gauze covered may have to be on the higher side because the wound is exuding and the gauze may be wet at any time.