Midazolam is a commonly used drug in gastrointestinal endoscopy due to the good cardiovascular stability and mild respiratory depression for elderly patients. However, there is the concern about the the longer and less predictable recovery or the potential for repeat sedation when the active metabolite becomes bioavailable. Remimazolam Tosilate is an innovative benzodiazepine with better sedation effect and less recovery or resedation issues than midazolam, which possibly make the drug more suitable in elderly patients. We aim to clarify whether remimazolam tosilate is better than midazolam in elderly patients undergoing gastrointestinal endoscopy.

Before starting the endoscopy procedures, patients were randomized to receive remimazolam tosilate or midazolam to maintain sufficient sedation, then remifentanil was slowly injected for patients' sufficient analgesia during the examination. We aim to use patients' recovery time, cognition function and other measurement scales to clarify whether remimazolam tosilate is better than midazolam in elderly patients undergoing gastrointestinal endoscopy.

Inclusion Criteria:

1. Scheduled to undergo a routine diagnostic or therapeutic gastrointestinal endoscopy ;
2. Age 60 to 75 ;
3. ASA physical status score of I, II or III;
4. A body mass index (BMI) of 19 to 28 kg/m2;
5. Systolic blood pressure of 90-140mmHg, diastolic blood pressure of 50-90mmHg, resting heart rate of 50-100bpm and blood pulse oxygen saturation ≥95%

Exclusion Criteria:

1. Those who are refused to be included;
2. Those who are allergic to the drugs used in this study;
3. Epilepsy and other mental illnesses, a history of addiction such as opiates and other analgesics and/or tranquilizers (hypnotics);
4. Severe cardiac dysfunction: NYHA cardiac functions grade 3-4, a history of recent myocardial infarction or cerebral infarction, severe conduction block or malignant arrhythmia;
5. Renal failure or liver cirrhosis;
6. Severe lung infection or upper respiratory tract infection;
7. Sleep apnea syndrome, difficult airway (Mallampati score of 3 or 4) or asthma status;
8. Advanced cancer accompanied by extensive intra-abdominal metastasis, acute and chronic obstruction of the gastrointestinal tract, bleeding and severe abdominal effusion;