Sedation is a component of the care of critically ill patients who are undergoing mechanical ventilation. Dexmedetomidine induces sedation while preserving a degree of arousability among patients in the intensive care unit (ICU), and its use has resulted in a shorter time to extubation, an increased number of days free from coma or delirium, a reduced incidence of agitated delirium, prevention of delirium, and lower mortality than other agents administered in certain populations. Hypotension and bradycardia are common side effects, which is lethal for the patients with persistent or severe hemodynamic instability.

The pharmacological properties of rimazolom suggest that it is an ideal sedative drug for critically ill patients, but there is no relevant clinical research to confirm it. Therefore, this study mainly discusses the efficacy and safety of remidazolam in ICU patients with mechanical ventilation, so as to provide theoretical basis for individualized sedation treatment of patients with mechanical ventilation.

1. Title: Efficacy and Safety of Remimazolam for Sedation in ICU Patients Undergoing Mechanical Ventilation
2. Research center: Single Center
3. The Design of the study: Randomized, Controlled, Non-inferiority Trial
4. The population of the study: The main inclusion criteria are 18 years old or above, invasive mechanical ventilation is required, and the clinical need is mild to moderate Sedated (RASS score 0 to -3) patients
5. Sample size: Enroll 488 patients (244patients in each group)
6. Interventions: Participants in the test group received remimazolam for sedation, while participants in the control group received dexmedetomidine, The analgesia drug in two group is fentanyl.
7. The aim of the research: To investigate the efficacy and safety of remimazolam for sedation in ICU patients undergoing mechanical ventilation
8. Outcome# 1) Primary outcome# the ratio of the time to reach the target sedation (RASS score, 0 to -3)in the total duration of drug infusion, and the duration of mechanical ventilation. 2)Secondary outcome#; Length of stay in ICU and Length of stay in hospital; Incidence of complications (including re-hospitalization); Total expenses during hospitalization
9. The estimated duration of the study#2-3years

Inclusion Criteria:

The main inclusion criteria are 18 years old or above, invasive mechanical ventilation is required, and the clinical need is mild to moderate Sedated (RASS score 0 to -3) patients.

Exclusion Criteria:

1. Refuse to participate in this study
2. Patients with severe bradycardia (HR<50 bpm)
3. Patients who is pregnancy
4. Patients with brain injury or neurosurgery
5. Patients receiving sedation for treatment indications (such as epilepsy), not to tolerate a ventilator.
6. Patients receiving any study medication within 30 days