104 patients who undergo painless colonoscopy from January 20,2024 to February 29,2024 will be randomized to two groups: propofol group and dexmedetomidine group. In the dexmedetomidine group,dexmedetomidine is infusion intravenously with a loading dose of 0.5 μg kg-1 for 10 min, then infusion at 0.3 μg kg-1 h-1 according to the ideal body weight of the patient until the end of colonoscopy. In the propofol group, Propofol is administrated 1 mg kg-1 intravenously, then titrated given by 0.5 mg kg-1 during the whole process.
104 patients who undergo painless colonoscopy from January 20,2024 to February 29,2024 will be randomized to two groups: propofol group and dexmedetomidine group. In the dexmedetomidine group,dexmedetomidine is infusion intravenously with a loading dose of 0.5 μg kg-1 for 10 min, then infusion at 0.3 μg kg-1 h-1 according to the ideal body weight of the patient until the end of colonoscopy. In the propofol group, Propofol is administrated 1 mg kg-1 intravenously, then titrated given by 0.5 mg kg-1.For all patients, if Ramsay sedation scale score reach 3, colonoscope will be inserted. During the whole process, maintenance Ramsay score of 3 to 4. Propofol 10 mg will be administrated as the rescue dose if body movement occur during colonoscopy. The primary outcome is the occurrence of hypotension. Key secondary outcomes are time-weighted average (TWA), area under the threshold (AUT) and cumulative duration of hypotension, as well as the maximum reduction in BP. Other secondary outcomes include(1) the incidence of bradycardia, hypoxemia or body movement；(2) discharge time (from the end of colonoscopy to discharge); (3) patients and endoscopists' satisfaction score (using an 11-point Likert scale, with 0 indicating "very dissatisfied" and 10 indicating "very satisfied"); (4) the incidence of dizziness, fatigue, or nausea and vomiting
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
PREVENTION
Masking
NONE
Enrollment
104
In the dexmedetomidine group, dexmedetomidine is infusion intravenously with a loading dose of 0.5 μg kg-1 for 10 min, then infusion at 0.3 μg kg-1 h-1 according to the ideal body weight of the patient until the end of colonoscopy. During the whole process, maintenance Ramsay score of 3 to 4. Propofol 10 mg will be administrated as the rescue dose if body movement occur during colonoscopy.
Propofol is administrated 1 mg kg-1 intravenously, then titrated given by 0.5 mg kg-1 until Ramsay score reach 3. During the whole process, propofol is given intermittently to maintain Ramsay score 3 to 4. If body movement happen, propofol 10mg will be administrated every time.
The primary outcome is the incidence of hypotension
Hypotension is defined as 20% decrease from baseline systolic blood pressure (SBP) or diastolic blood pressure (DBP), or SBP \< 90, and/or DBP \< 50 mmHg
Time frame: The time during colonoscopy, an average of 15 minutes
Area under the threshold (AUT) of hypotension
AUT=depth of hypotension below (a 20% decrease in baseline SBP or DBP) or (90 mm Hg of SBP or 50 mm Hg of DBP)× time in minutes spent of hypotension. As an example, a patient undergoes colonoscopy that lasts 15 min, in which he experiences 2 episodes of hypotension, all lasting for 1 min and all with a minimal SBP of 80 mm Hg. The AUT = 2 min × (90 -80= 10 mm Hg under the SBP threshold of 90 mm Hg) = 2×10 = 20 mm Hg per minute.
Time frame: The time during colonoscopy, an average of 15 minutes
Time-weighted average (TWA)
TWA is calculated as the AUT divided by the total duration of colonoscopy
Time frame: The time during colonoscopy, an average of 15 minutes
Cumulative duration of hypotension
The total time of patients experience hypotenion（hpotension defined as 20% decrease from baseline systolic blood pressure (SBP) or diastolic blood pressure (DBP), or SBP \< 90, and/or DBP \< 50 mmHg)
Time frame: The time during colonoscopy, an average of 15 minutes
Maximum reduction in blood pressure (BP)
Maximum reduction in systolic blood pressure (SBP) ,diastolic blood pressure (DBP) and mean arterial pressure (MAP) from baseline
Time frame: The time during colonoscopy, an average of 15 minutes
The incidence of bradycardia
Bradycardia is defined as heat rate(HR) \<50 beats/min
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Time frame: The time during colonoscopy, an average of 15 minutes
The incidence of hypoxemia
Hypoxemia is defined as oxygen saturation (SpO2)\<90%
Time frame: The time during colonoscopy, an average of 15 minutes
The body movement
The twisting of the patient's body due to the stimulation of the colonoscopy, making it difficult to proceed with the procedure
Time frame: The time during colonoscopy, an average of 15 minutes
Discharge time
From the end of colonoscopy to discharge
Time frame: From the end of colonoscopy to discharge，an average of 40 minutes
Patients satisfaction score
Using an 11-point Likert scale, with 0 indicating "very dissatisfied" and 10 indicating "very satisfied"
Time frame: When the patient is fully awake after colonoscopy，an average of 5 minutes
Endoscopists'satisfaction score
Using an 11-point Likert scale, with 0 indicating "very dissatisfied" and 10 indicating "very satisfied"
Time frame: At the end of colonoscopy,an average of 15 minutes
The incidence of dizziness
The investigators consider it dizziness if patients fell any dizziness
Time frame: From the end of colonoscopy to discharge，an average of 40 minutes
The incidence of fatigue
The investigators consider it fatigue if patients fell any fatigue
Time frame: From the end of colonoscopy to discharge，an average of 40 minutes
The incidence of nausea and vomiting
The investigators consider it nausea and vomiting if patients fell any nausea and vomiting
Time frame: From the end of colonoscopy to discharge，an average of 40 minutes