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