Decubitus ulcers, also known as pressure ulcers, are tissue ulcers and necrosis caused by long-term pressure on local tissues with impaired blood circulation and continuous ischemia, hypoxia, and malnutrition. clinically, pressure ulcers are usually divided into four phases. 1. bruising and erythema phase: at the beginning of the pressure ulcer, the local skin under pressure appears red, swollen, hot, numb, or painful to the touch, but the skin surface is not broken, which is a reversible change. 2. inflammatory infiltration phase: the red and swollen area continues to pressure, blood circulation is still not improved, venous return is blocked, the color of the surface of the skin under pressure turns to purplish-red, subcutaneous hard knots are produced, epidermal blisters are formed. The blisters are easily broken, revealing a moist and red trauma, and the patient feels pain; 3. Superficial ulcer stage: the whole body skin is destroyed, which can be deep to the subcutaneous tissue and deep tissue. The epidermal blisters gradually expand and break down, and the dermis has a traumatic surface with yellow exudate. The infection is covered with pus on the surface, resulting in necrosis of superficial tissues, formation of ulcers, and increased pain; 4. Necrotic ulcer stage: necrotic tissues invade the subdermis and muscle layer, and the infection expands to the periphery and deeper, and can reach the bone surface. At this time, the necrotic tissue is blackened, purulent secretions increase, and there is a foul smell. In severe cases, the bacteria may enter the bloodstream and cause septic sepsis, resulting in life-threatening infection. For patients who are bedridden for a long time, pay attention to local skin care, turn over regularly, scrub often, keep the skin clean and dry, and avoid friction. Once the skin is found to be under excessive pressure and in a state of malnutrition and poor blood flow, timely intervention is required to deal with it. Pay attention to strengthening nutrition, and if necessary, use air cushion and air ring care to avoid long-term pressure on local tissues.