Application of Remimazolam Combined With Esketamine in Painless Gastroscopy and Colonoscopy in Elderly Patients

The objective of this clinical trial is to assess the feasibility of the remimazolam combined with esketamine OFA (opioid-free anesthesia) protocol for painless gastroscopy and colonoscopy in elderly patients and to determine if it is non-inferior to the traditional OA (opioid-containing anesthesia) protocol. The main questions it aims to answer are: * Is the remimazolam combined with esketamine protocol feasible for painless gastroscopy and colonoscopy in elderly patients? * Is the OFA protocol superior to the OA protocol? Participants will: * During anesthesia induction, the experimental group will receive remimazolam combined with esketamine for anesthesia, while the control group will receive remimazolam combined with remifentanil. * Record respiratory and circulatory indicators and adverse reaction times.

Inclusion Criteria: 1. Patients undergoing painless gastroenteroscopy in outpatient clinics; 2. aged 65 years and above; 3. American Society of Anesthesiologists (ASA) grades I - III. Exclusion Criteria: 1. Patients with abnormal liver or kidney function; 2. known respiratory or endocrine diseases; 3. Patients with uncontrolled hypertension and NYHA classification Ⅲ-Ⅳ; 4. Taking monoamine oxidase inhibitors, sedatives, analgesics, hypnotics, antipsychotics, antiemetics or antidepressants; 5. Addiction to tobacco and alcohol; 6. Patients allergic to the investigational drug; 7. expected difficult airway; 8. Body mass index (BMI) \>35kg/m\^2; 9. Have participated in other clinical trials within the past three months; 10. Patients with psychosocial illness or cognitive dysfunction and inability to cooperate or communicate.