Terminal pneumonia in the elderly refers to pneumonia caused by various diseases in the late stage or long-term bed rest, extreme physical exhaustion leading to low immune function and decreased respiratory defense function. Common diseases that cause terminal pneumonia include: various cerebrovascular diseases in the recovery stage, late-stage malignant tumors, severe diabetes patients, liver and kidney failure, brain trauma, radiotherapy and chemotherapy patients, acquired immunodeficiency syndrome (AIDS), after major surgery, organ transplant patients, and patients with indwelling catheters and endotracheal intubation. These patients are often called immunocompromised hosts, and the incidence of combined infections is quite high, among which lung infection is the most common and the main cause of death.