ICU is a place where critical illnesses are treated centrally, with medical staff as the main body, medical equipment as the guarantee, and continuous monitoring and treatment as the means. ICU can be divided into comprehensive ICU and specialized ICU, which may centralize or decentralize treatment for patients of different specialties, and it can provide the best medical service for patients. ICU is also called intensive care medicine department, which can realize the centralization of critical patients treatment, reduce the investment of medical resources, improve the level of treatment, and reduce the death rate of critically ill patients. Patients who are transferred to the ICU are usually patients with unstable or potentially unstable vital signs, with one or more organs or systems that have been involved and are or are potentially life-threatening.