Uses: Used for monitoring anesthesia index, monitoring anesthesia index of patients during surgery Clinical significance 1. Precise anesthesia allows the patient to have no awareness during surgery 2. Improve the quality of recovery after surgery and shorten the recovery time 3. Make post-operative recovery more complete 4. Reduce the incidence of nausea and vomiting after surgery 5. Guide the ICU to calm the amount of medicinal and maintain a more stable level of sedation 6. For outpatient surgery anesthesia, can shorten the observation time after surgery 7.More accurate use of anesthetics to make anesthesia more stable, while reducing the amount of anesthesia.