Efficacy and Safety of S-ketamine in Elderly Patients Undergoing Non-cardiac Surgery: a RCT（ESSENCE）

Inclusion Criteria: * 1\) Aged \> 65 years old, no gender limitation; * 2\) patients undergoing elective thoracic, abdominal and orthopedic surgery; * 3\) ASA score is Class I-Class \~III; * 4\) 18 kg/ m2\<BMI\<30kg/m2； * 5\) The operation time is estimated to be 2 h-4 h; * 6\) Know clearly and voluntarily participate in this study, and sign informed consent form by oneself. Exclusion Criteria: * 1\) patients with severe chronic pain; * 2\) Anemia or thrombocytopenia, Hb \< 90 g/L, PLT \< 80 × 109/L; * 3\) Severe liver dysfunction, AST and/or ALT≥2.5×ULN, and TBIL ≥ 1.5 × ULN; * 4\) severe renal dysfunction, blood creatinine is greater than the upper limit of normal; * 5\) Severe cardiovascular history (such as myocardial ischemia, heart failure and arrhythmia); Angina pectoris (unstable angina pectoris) caused by insufficient blood supply to the coronary vessels of the heart, or myocardial infarction in the past 6 months; QT interval prolongation (≥460ms in males and ≥ 470 ms in females); * 6\) Patients with hypertension whose blood pressure is not satisfactorily controlled by antihypertensive drugs (systolic blood pressure in sitting position during screening stage ≥180 mmHg, and/or diastolic blood pressure during screening stage ≥ 100 mmHg); * 7\) Patients with craniocerebral injury, possible intracranial hypertension, cerebral aneurysm, cerebrovascular accident history and central nervous system disease history; * 8\) patients with glaucoma or serious increase in intraocular pressure risk; * 9\) patients with mental system diseases (schizophrenia, mania, bipolar disorder, mental disorder, etc.) and drug history and cognitive dysfunction; History of cognitive psychiatric disorders such as postoperative delirium; Pregnant or lactating women; * 10\) high risk surgery, is expected to enter the ICU after surgery; * 11\) to moxa ketamine hydrochloride and its drug components allergy or taboo; * 12\) Being a subject and having participated in clinical trials for other drugs in the past three months; * 13\) There is communication disorder; * 14\) Patients considered by the investigator to be ineligible for participation in this trial.