Decubitus ulcers, also known as pressure sores and pressure ulcers, are caused by a lack of nutrients in the skin and subcutaneous tissues due to long-term pressure on local tissues that affects blood circulation, resulting in damage, ulceration and even necrosis. They usually occur in areas of protruding bones that are under pressure, such as the sacrum, ankles, heels, and buttocks. There are many reasons for decubitus ulcers, and the common causes are as follows: 1. Pressure factors: including vertical pressure, friction, shear force, etc., the skin is stimulated by pressure for a long time and blood flow is poor, resulting in local skin ischemia, hypoxia, damage, etc., which leads to the formation of decubitus ulcers; 2. Nutritional deficiencies: Patients lack nutrition in the body due to insufficient nutritional intake or nutritional absorption disorders, which in turn causes the body’s muscles to 3. Decreased skin resistance: stimulation by various secretions and exudates, such as urine and feces, etc., in addition to loose skin and lack of elasticity in the elderly, can lead to decreased skin resistance, increasing the chances of bedsores; 4. Disease factors: diseases such as diabetes, kidney failure, heart failure, etc., that affect the patient’s ability to move The presence of bed sores can be caused by poor blood circulation in the local tissues due to sensory impairment of the body’s activities; 5. Drug factors: drugs such as analgesics, sedatives and vasoconstrictors can also contribute to the formation of bed sores.