Sedation Efficacy and Safety of Remazolam Besylate in Ventilated Surgical Critically Ill Patients

Inclusion Criteria: * 18-64 years old * must accept no-cardiac elective surgery * must under general anaesthesia * can be combined regional tissue anesthesia * must admitted to ICU with tracheal intubation after general anaesthesia - expected mechanical ventilation time must more than 24 hours * light or moderate sedation must needed Exclusion Criteria: * intracranial surgery or severe neurological or spinal cord disease * schizophrenia, epilepsy, and Parkinson's disease * coma, severe dementia, or language barrier before surgery * cardiac dysfunction or arrhythmia * severe liver dysfunction(Child-Pugh C class) * severe kidney dysfunction * use of dexmedetomidine or remifentanil besylate 24 hours before or during surgery * pregnancy or lactation * any investigational drug useage 30 days before surgery * refuse to participant.