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 groups and/or performs unconventional diagnostic or monitoring procedures).