Emergence delirium can lead to a range of clinical problems and is even associated with short-term behavioral changes in children. Pediatric ear, nose, and throat (ENT) surgery is one of the most common surgical types for postoperative delirium in children. Sevoflurane anesthesia is also a known cause of postoperative delirium. Therefore, this study aims to explore whether there is a difference in the incidence of postoperative delirium in children under remimazolam general anesthesia and sevoflurane anesthesia.

children aged 3-6 years old were randomly and equally allocated into two groups: Group R remimazolam, Group S with sevoflurane, respectively.

Inclusion Criteria:

1. Age 3-6 years;
2. American Society of Anaesthesiologist (ASA) I or II;
3. Booked for Tonsillectomy and Adenoidectomy;
4. BMI for age between the 25th and 85th percentiles according to the 2000 Centers for Disease Control and Prevention (CDC) growth charts.

Exclusion Criteria:

1. Children (ASA III- IV) who had abnormal liver and kidney function, cardiovascular, endocrine dysfunction, or any other organ dysfunction;
2. Allergy or hypersensitive reaction to remimazolam;
3. mental disorder
4. Recently respiratory infection;
5. Other reasons that researchers hold it is not appropriate to participate in this trial: under specialized care or lived in social welfare institutions, or any other factors that could affect their ability to participate in the study.