Definition: Acute gastrointestinal erosions and ulcers that occur in the organism under severe stress conditions such as various types of severe trauma, critical illness, and surgery, mainly manifesting as gastrointestinal bleeding. Pathogenesis and etiology: The exact mechanism of stress ulcer is still not fully understood. However, the main mechanism lies in the increase of gastric mucosal damage factor and the decrease of gastrointestinal mucosal protection ability. 1. Under stress, the nerve center and neuropeptides act on the gastrointestinal tract mainly through the autonomic nervous system and pituitary-adrenal axis, and the pituitary-adrenal system activates, causing disruption of gastrointestinal hormone secretion and increased gastric acid secretion. 2. Impaired gastrointestinal mucosal barrier: Under stress, blood redistribution, reduced visceral blood flow, combined with traumatic blood loss, surgical bleeding, hypoxia, acidosis and other effects, resulting in microcirculatory disorders; local gastrointestinal mucosal blood flow (gastric mucosal blood flow) decreases, gastric mucus secretion decreases, and the gastric mucosal barrier is damaged. Orthopedic patients are more likely to have postoperative stress ulcers than other general surgeries also due to: 1. chronic bone and joint pain patients take long-term oral non-steroidal anti-inflammatory drugs (NSAIDs) or hormones to control pain. nSAIDs inhibit gastric mucosal secretion, leaving the gastrointestinal mucosal barrier in a compromised state, increasing the risk of stress ulcers. 2.Bone blood supply is rich, and blood loss is high in acute trauma such as femur fracture. Fracture surgery is usually more likely to be complicated by bleeding than other surgeries, and the bleeding volume is larger. 3, anticoagulation therapy: certain orthopedic surgeries require anticoagulation therapy for the prevention of deep vein thrombosis. Anticoagulant drugs make the clotting time prolonged, which is not conducive to the formation of thrombosis on the surface of gastric mucosa to stop bleeding, and the ulcer healing is difficult.