Safety and Efficacy of Fospropofol vs Propofol During Invasive Mechanical Ventilation.

The goal of this clinical trial is to compare the safety and efficacy of fospropofol and propofol during sedation in invasively mechanically ventilated patients in the Anesthesia Intensive Care Unit (AICU). Specific objectives include the following: * Evaluate the sedative effects of fospropofol and propofol in invasively mechanically ventilated patients. Compare the sedative effects of the two medications using relevant clinical indicators and scoring tools, such as the Richmond Agitation-Sedation Scale (RASS). * Compare the safety of fospropofol and propofol during sedation. Monitor medication-related adverse reactions, such as respiratory depression, hypotension, arrhythmias, headache, injection site pain, and assess the differences in adverse reaction incidence between the two medications. * Compare the characteristics of recovery from sedation between PPD and propofol. Focus on the time from sedation to emergence from sedation and compare the differences in recovery time between the two medications. Participants will be sedated with fospropofol or propofol during invasive mechanical ventilation.