The purpose of this study is to evaluate the efficacy and safety of fospropofol disodium for injection compared to propofol for deep sedation in mechanically ventilated ICU patients.

This is a randomized, open-label, small sample study using fospropofol disodium and propofol for deep sedation in mechanically ventilated ICU patients. Subjects are randomized to different treatment groups (including 1 for fospropofol disodium and 1 for propofol). Remifentanil is co-administered with fospropofol or propofol. Efficacy and safety profiles of fospropofol disodium and propofol are to be monitoted.

Inclusion Criteria:

• Age ≥ 18 and ≤ 80 years; Expected to require deep sedation ≥8 hours; Requirement for deep sedation (a Narcotrend index between 13 and 64).

Exclusion Criteria:

• Body mass index (BMI) <18 or >30 kg/m2; Contraindicate or allergic to study drugs; Moribund state; Expected to have a general anesthesia within 8 hours; Myasthenia gravis; Acute hepatitis or serious hepatic dysfunction (Child-Pugh class C); Chronic kidney disease with glomerular filtration rate (GFR) < 29 ml/min/1.73m2; Systolic blood pressure less than 90 mm Hg after appropriate intravenous volume replacement and continuous infusions of 2 vasopressors; Acute severe neurological disorder and any other condition interfering with RASS assessment; Pregnancy or lactation; Unstable angina; Acute myocardial infarction; Left ventricular ejection fraction less than 30%; Heart rate less than 50 beats/min; Second- or third-degree heart block in the absence of a pacemaker; Alcohol abuse or drug abuse.