the investigators are conducting a clinical study on the efficacy and safety of remimazolam for induction and maintenance of anesthesia in elderly patients. Project number: CRCF-YXFN-202401029, funded by the Red Cross Foundation of China and will take more than 2 years to complete.

This is a single-center, randomized, controlled clinical study, randomized 60 elderly subjects undergoing general anesthesia for elective surgery. According to the random number method, propofol group (control group, group P) and remimazolam group (experimental group, group R), 30 cases in each group.

By participating in this study, it is possible to make anesthesia induction rapid and stable, stable intraoperative circulation, rapid recovery and safe and comfortable, reduce the Incidence of intraoperative awareness, arrhythmia, postoperative delusion, and so on, which is conducive to rapid postoperative recovery and reduce hospitalization costs.

Research background: Rapid and steady anesthesia induction, stable intraoperative circulation, rapid recovery, safe and comfortable, and few adverse reactions are the goals of anesthesiologists. Accelerating the surgical turnover and improving the efficiency are the clinical problems that need to be solved. Clinical general anesthesia often adopts static inhalation compound anesthesia to give full play to the advantages of intravenous and inhalation anesthesia and reduce their respective adverse reactions. Remimazolam, as a new ultra-short-acting benzodiazepine sedative, is not widely used in elderly patients, but its rapid onset, short time half-life, less accumulation, little cardiopulmonary inhibition, no injection pain, and can be antagonized by flumazenil, showing an irreplaceable advantage.

Study objective: To observe the efficacy and safety of remimazolam for the induction and maintenance of anesthesia in elderly patients, and to provide a new option for anesthesia management in elderly and critically ill patients.

Study method: This topic adopts a single-center, prospective, randomized, controlled research method, and expects to include 60 elderly subjects with general endotracheal anesthesia for elective surgery.

Inclusion Criteria:

1. Patients undergoing surgery for clinically diagnosed thyroid tumors
2. Patients with general anesthesia
3. Patients requiring endotracheal intubation
4. American Society of Anesthesia gradeⅡ to grade Ⅲ
5. age 60-75 years old
6. body mass index was between 18 and 28
7. Patients or their family was clear about the study process and volunteered to participate.

Exclusion Criteria:

1. Patients with known allergy to remimazolam or with previous history of severe allergy and family history
2. Patients with long-term use of narcotic analgesics, sedatives, or non- steroidal anti-inflammatory drugs
3. Patients with drug taking, opioid dependence or tolerance
4. Patients with combined brain injury or intracranial hypertension
5. Patients with severe abnormal function of the heart, lung, liver, kidney and other major organs
6. Patients with bradycardia, with a heart rate lower than 55 beats / minute or a high atrioventricular block
7. Patients with a previous history of allergic disease
8. Patients with a previous history of mental illness
9. Patients with a foreseeable difficult airway
10. The investigator does not consider it appropriate to attend this clinical investigator.

The enrolled patients and the data collectors were blinded to the grouping status