Safety and Efficacy Evaluation of S (+) - Ketamine in Children

Inclusion Criteria: 1. Age ≤17 years; 2. Scheduled for elective digestive tract surgery, orthopedic surgery, urological surgery , ear surgery or other surgeries under general anesthesia; 3. ASA physical status I～Ⅲ; 4. The informed consent form was signed by the patients or the guardians. Exclusion Criteria: 1. The expected length of hospital stay of the patient is less than 48h; 2. Patients expected to be admitted to the ICU after surgery; 3. Patients expected to return to the ward with tracheal catheter after surgery; 4. Be allergic to S (+) - ketamine; 5. Patients with severe disorder of consciousness or mental system diseases (schizophrenia, mania, bipolar disorder, psychosis, etc.) or cognitive dysfunction; 6. Patients with congenital heart disease or severely developmental retardation; 7. Patients with any of the following contraindications of S (+) - ketamine: 1. Patients with risk of serious rise of blood pressure or intracranial pressure; 2. Patients with high intraocular pressure (glaucoma) or penetrating ocular trauma; 3. Patients with poorly controlled or untreated hypertension (Resting systolic blood pressure greater than 180 mmHg, or resting diastolic blood pressure greater than 100mmHg); 4. Patients with untreated or undertreated hyperthyroidism.