RemImazolam Besylate for ICU-sedation in Patients With Mechanical Ventilation After Oral and Maxillofacial Surgery

Inclusion Criteria: * Age ≥18 years old; * After undergoing oral and maxillofacial surgery, it is expected that a ventilator will be needed to assist with breathing; * mechanical ventilation patients with expected ICU stay time \<72h; * People who need immediate sedative treatment; * Obtain informed consent from subject or legal representative; Exclusion Criteria: * Pregnancy； * Can not get RASS score from patients; * Allergy to drugs; * Proven acute and severe intracranial or spinal nerve disease due to vascular, infection, intracranial dilation, or injury; * Uncompensated acute circulatory failure at randomization (severe hypotension with MAP\<50 mmHg despite adequate fluid resuscitation and vasopressor therapy); * Severe bradycardia (heart rate \<50 beats/min) or degree II-III heart block (unless a pacemaker is installed); * A history of long-term use of benzodiazepines or opioids; * Subjects receiving sedation for indications other than to tolerate ventilators (e.g., epilepsy); * Continuous sedation is unlikely to be required during mechanical ventilation (e.g. Guillain-Barre syndrome); * Patients determined by the clinician to be unlikely to be removed from mechanical ventilation, such as diseases/injuries that primarily affect respirator neuromuscular function and conditions that clearly require long-term ventilation support (such as high spinal cord injury); * Participation in any other interventional study (any study that assigns subjects to different treatment gro…