A Clinical Study Evaluating Sedation of Intravenous Administration of HSK3486 in ICU Patients Undergoing Long-Term Mechanical Ventilation

Inclusion Criteria: 1. Patients who require tracheal intubation for mechanical ventilation, with expected sedation duration of longer than 96 h; 2. Patients requiring a target RASS score of -1 to -2 for sedation; 3. Aged ≥ 18 and \< 80 years old, with no gender requirement; 4. BMI ≥ 18 kg/m2 and ≤ 30 kg/m2; 5. The patients or their family members fully understand the objectives and significance of this study, and voluntarily participate in this clinical study and sign the informed consent form. Exclusion Criteria: 1. Patients known to be allergic to eggs, soy products, opioids and their antidotes, and Propofol; patient having contraindications to Propofol, opioids and their antidotes; 2. Patients who have received propofol for more than 3 days in the ICU or in the general ward before being transferred to the ICU before signing informed consent form; 3. Patients having the following medical history or evidence of any of the following at screening, which may increase sedation/anesthesia risk: 1. Cardiovascular system: New York Heart Association (NYHA) Class III and IV heart failure, Adams-stokes syndrome; acute coronary syndrome (ACS) that occurs within 6 months before screening; bradycardia requiring medication and/or heart rate ≤ 50 beats/min; a history of severe arrhythmia such as II-III degree atrioventricular block (excluding patients using pacemakers); acute and chronic myocarditis; 2. Patients with hyperlipidemia: Defined as patients with TC ≥ 5.2 mmol/L or LDL-C ≥ 3.4 mmol/L at screening, or patients with severely increased blood pressure or blood glucose despite their blood lipid levels meeting the requirements, rendering the patients huge risk of cardiovascular diseases per the investigator's judgment; patients with acute pancreatitis; 3. Patients with mental diseases (e.g., schizophrenia, depression) and cognitive dysfunction; grand mal epilepsy and convulsion; head injury, intracranial hypertension, cerebral aneurysm; Glasgow Coma Score (GCS) ≤ 12; SOFA Score \> 9; past history of psychotropic and narcotic drug abuse; history of alcohol abuse within 3 months before screening; long-term use of psychotropic drugs; 4. Patients with high paraplegia and general paralysis; patients with unstable hemodynamics; 5. Severe hepatic and renal insufficiency (liver function: refer to child-pugh grade C; renal function: glomerular filtration rate eGFR ≤ 30 mL/(min•1.73 m2) \[eGFR is calculated using the Modification of Diet in Renal Disease (MDRD) equation: eGFR = 175 × serum creatinine (SCr)-1.234 × age-0.179 × 0.79 (females)\]; patients undergoing dialysis; 6. Patients with an expected survival of less than 1 week; 7. Other situations unsuitable for enrollment per the investigator's consideration. 4. Pregnant or breastfeeding females: women or men of child-bearing potential who are unwilling to use contraception during the trial; subjects who are planning pregnancy within 1 month after the trial starts (including male subjects); 5. Have participated in any other clinical trials within 1 month prior to screening; 6. Other conditions that patients are judged by the investigator to be unsuitable for participating in the study.