The physiological reserves of critically ill patients are relatively low, and the risk of complications related to tracheal intubation in the ICU is higher than in the operating room. ICU tracheal intubation complications account for approximately 40% -45% of patients, including severe hypotension (10% -43%), severe hypoxemia (9% -25%), and cardiac arrest (2% -3%).Ciprofol is a novel 2,6-disubstituted phenol derivative that targeting γ-aminobutyric acid type A (GABAA)-receptor. There are four indications of ciprofol that have been approved by NMPA in recent two years: sedation and anesthesia in non-tracheal intubation procedure/operation, induction and maintenance of general anesthesia, sedation during intensive care, sedation and maintenance in gynecological outpatient surgery. The aim of this study is to compare the effects of propofol and propofol on the circulatory system during tracheal intubation in ICU patients, in order to provide a safer induction sedation regimen for emergency tracheal intubation in critically ill patients.

Inclusion Criteria:

• Patients who need to undergo tracheal intubation under sedation after entering the ICU;
• Age range from 18 to 85 years old;
• Patients or their families have a full understanding of the purpose and significance of this trial, voluntarily participate in this clinical trial, and sign an informed consent form.

Exclusion Criteria:

• Patients who are allergic to the study drugs, or patients with contraindications to the study drugs;
• Patients with difficult airways (MACOCHA ≥ 3 points);
• Patients who require emergency intubation due to sudden cardiac arrest;
• Patients who require conscious intubation;
• Patients who can maintain mean arterial pressure (MAP) above 65mmHg using of one or more vasoactive drugs (equivalent (-)-noradrenaline > 0.3 μg kg min);
• In a state of imminent death;
• Pregnant and/or lactating women; Subject judged by the investigator to have any other factors unsuitable for participation in the study