A Phase 4 interventional study of Remimazolam besylate and Propofol in Colonic Polyp and Sedation Complication, sponsored by Clinical Hospital Centre Zagreb. Recruiting at 1 site in Croatia. Open to participants aged 18 Years to 60 Years. Per ClinicalTrials.gov, last updated 2026-03-06.
Sponsored by Clinical Hospital Centre Zagreb · Phase 4, Interventional, and Treatment
The goal of this prospective, randomized, controlled study is to compare remimazolam besilat/sufentanyl and propofol/sufentanyl in patients during colonoscopic polypectomies procedures.
Patients undergoing colonoscopic polypectomies in procedural sedation using remimazolam besylate/sufentanyl are circulatory and respiratory as or more stable when compared with propofol/sufentanyl sedation.
Following the approval for the research by the Ethics Committee (Clinical Hospital Center, Zagreb, Croatia), a total of ninety (90) patients will be included in the research. Forty five (45) patients will be assigned to the study group (SG) and forty five (45) patients to the control group (CG).
Research Goals:
Primary goals
Secondary goals
Patients from both groups, upon arrival to the gastroenterology ward will have a peripheral venous line installed by puncturing one of the veins on the dorsum of the hand or forearm. The veins of choice include the rete venosum dorsale manus, vena cephalica and vena basilica, and an 18 G or 20 G intravenous cannula will be placed. After confirming the functionality of the venous line, the intravenous administration of Fifty will follow. The infusion rate will depend on the patient's BMI and circulatory status.
Study Group (SG):
A total of 45 patients are included in this group. After non-invasive monitoring, positioning the patient in the left lateral position and placing a nasal catheter with a continuous oxygen flow of 3 l/min, the patient will receive the intravenous opioid analgesic Sufentanyl 0.2 mcg/kg over a period of 30 seconds.
After 1 to 2 minutes the patient will receive remimazolam besylate intravenously in a dose of 5.0 mg over a period of 1 minute. After two minutes, a maintenance dose of 2.5 mg will be administered using the titration method over a period of 15 seconds until the desired sedation effect is achieved.The maximum intravenous dose of administered remimazolam besylate will be 33 mg.BIS monitoring and a modified MOAA/S (Modified Observers Assessment of Alertness and Sedation Scale) scale will be used to assess the depth of sedation. The first measurement of the depth of sedation will be initially following the complete administration of the sedative remimazolam besylate and will serve as the initial/starting point. Afterwards, a measurement of the MOAA/S scale will be performed every 30 seconds for a total of 3 minutes. The most desirable level of sedation for the planned procedure is defined as a MOAA/S measurement of \<3.
Control group (CG)
A total of 45 patients will be included in this group.
Firstly, non-invasive monitoring will be applied to the patient, then they will be placed in the left lateral position and through a nasal catheter a continuous oxygen flow of 3l/min will be administered. The patient will be given intravenous opioid analgesia Sufentanyl 0.2 mg/kg. within 30 seconds. After approximately 1-2 minutes the patient will receive the titrated anesthetic propofol intravenously at a dose of 1.5 to 2.5 mg/kg, (20.0 to 30.0 mg propofol every 10 seconds). In elderly patients and patients with ASA grade III, the total dose of propofol will be at least 1 mg/kg with an administration rate of 10.0 to 20.0 mg every 10 seconds.
Sedation will be maintained using propofol in a continuous intravenous infusion. The maintenance dose given will be 0.5 to 1.0 mg propofol/kg/hour.
BIS monitoring and a modified MOAA/S (Modified Observers Assessment of Alertness and Sedation Scale) scale will be used to assess the depth of sedation. The first measurement of the MOAA/S score will be conducted after the total intravenous propofol dose was administered and this first measurement will be considered the starting/zero measurement. MOAA/S scale point will be measured every 30 seconds for a total of 3 minutes. A measurement of \<3 points will be considered the most desirable level of sedation for the planned procedure.
In both study groups the following parameters will continuously be measured:
Primary measurement:
Upon patients' arrival to the pre-op room (first measurement) and 5 minutes before proceeding to the operating theater.
During the procedure:
Before administering the sedative remimazolam besylate or propofol and at 3, 5, 10, and 15 minutes. (every 5 minutes during the procedure) until the patient is consciousness, followed by the first of five sets of MOAAS/S measurements upon completion of the procedure or when the last dose of medication is given.
Frequency of hypotension in both groups of patients and comparing the results between the SG and CG.
Hypotension during the procedure using sedation or propofol is defined as:
a decrease in systolic systemic pressure of 20% or more compared with the first measurement before the administration of remimazolam besylata or propofol.
A mean arterial pressure of ≤60 mmHg during while the patient is under sedation.
4. Sinus bradycardia is defined as a decreased cardiac rate. 5. The frequency of respiratory depression compared between the two groups, SG and CG.
Respiratory depression during sedation is defined as:
Respiratory rate of \<8 breaths per minute and/or a peripheral blood oxygen percentage of (SpO2) \<90.
6. BIS monitoring. 7. The success of procedural sedation using remimazolam besylate and sedation using propofol:
Will be shown as the percentage of successfully sedated patients defined as:
The completion of endoscopic polypectomy, without the need for rapid/fast acting emergency sedation or a maximum number of 5 additional doses given withing 15 minutes of the first dose to maintain adequate sedation.
8. The time to achieve adequate sedation is defined as the time from administering the first dose of medication until achieving \<3 points on the MOAA/S scale and/ora BIS.
9. The time to achieve full consciousness is defined as the time since the administration of the last dose of medication until the patient is fully aware, or until the patients has 5 points on the MOAA/S scale.
10. The time needed for the patient to fully recover after the procedure in both groups is defined by the criteria for patient dismissal using the - Modified Aldrete score scale.
The total volume of the given crystalloid solution (Plasma-lyte) will be measured in both groups.
377 studies on the registry are indexed under Colonic Polyps; 57 are open to participants now.
This study's planned enrollment of 90 is below the median of 274 across 250 interventional studies indexed under Colonic Polyps.
Browse Colonic Polyps studies →Clinical Hospital Centre Zagreb is the lead sponsor of 32 studies on the registry; 8 are open to participants now.
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Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
The share of blood the heart’s main pumping chamber (the left ventricle) pushes out with each beat, measured by an echocardiogram (heart ultrasound) or a MUGA scan. About 50–70% is normal.
Chronic obstructive pulmonary disease: long-term lung disease that makes it hard to breathe out, including emphysema and chronic bronchitis.
BMI (body mass index)
Weight in kilograms divided by height in metres squared. Example: 70 kg and 1.75 m gives 70 ÷ (1.75 × 1.75) ≈ 22.9.
What counts as overweight or obesity differs between countries (some use lower cut-offs), so go by the range the study states.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
LVEF (left ventricular ejection fraction)
The share of blood the heart’s main pumping chamber (the left ventricle) pushes out with each beat, measured by an echocardiogram (heart ultrasound) or a MUGA scan. About 50–70% is normal.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
COPD
Chronic obstructive pulmonary disease: long-term lung disease that makes it hard to breathe out, including emphysema and chronic bronchitis.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Drug: Remimazolam besylate
Drug: Propofol
The patient will receive the intravenous opioid analgesic sufentanyl 0.2 mcg/kg over a period of 30 seconds. After 1 to 2 minutes the patient will receive remimazolam besylate intravenously in a dose of 5.0 mg over a period of 1 minute. After two minutes, a maintenance dose of 2.5 mg will be administered using the titration method over a period of 15 seconds until the desired sedation effect is achieved.The maximum intravenous dose of administered remimazolam besylate will be 33 mg.BIS monitoring and a modified MOAA/S scale will be used to assess the depth of sedation. The first measurement of the depth of sedation will be initially following the complete administration of the sedative remimazolam besylate and will serve as the initial/starting point. Afterwards, a measurement of the MOAA/S scale will be performed every 30 seconds for a total of 3 minutes. The most desirable level of sedation for the planned procedure is defined as a MOAA/S measurement of \<3.
The patient will be given intravenous opiod analgesia sufentanyl 0,2 mg/kg.within 30 seconds. After approximately 1-2 minutes the patient will receive the titrated anestetic propofol intravenously at a dose of 1,5 to 2,5 mg/kg (20,0 mg. propofol evry 10 seconds). In elderly patients and patients with ASA grade III, the total dose of propofol will be least 1 mg/kg with an administration rate of 10 every 10 seconds.
Hemodynamic Stability - Mean Arterial Pressure (MAP)
Mean arterial pressure (mmHg) measured at multiple timepoints to assess overall circulatory stability. Comparison of MAP values between remimazolam and propofol groups.
Time frame: from enrollment up to 2 hours after the procedure; approximately 2-4 hours per participant.
Hemodynamic Stability - Systolic and Diastolic Blood Pressure
Systolic and diastolic blood pressure (mmHg) measured at multiple timepoints to assess circulatory stability. Comparison between remimazolam and propofol groups.
Time frame: from enrollment up to 2 hours after the procedure; approximately 2-4 hours per participant.
Hemodynamic Stability - Heart Rate
Heart rate (beats per minute) measured continuously via ECG monitoring. Comparison of heart rate values between study groups.
Time frame: from enrollment up to 2 hours after the procedure; approximately 2-4 hours per participant.
Incidence of Hypotension
Percentage of participants experiencing hypotension defined as either: Decrease in systolic blood pressure ≥20% from baseline value (measured before remimazolam or propofol administration), OR Mean arterial pressure (MAP) ≤60 mmHg during procedural sedation
Time frame: from enrollment up to 2 hours after the procedure; approximately 2-4 hours per participant.
Incidence of Bradycardia
Bradycardia is defined as a heart rate (HR) below 50 beats per minute (bpm), or a clinically significant decrease in HR of ≥20% from the pre-induction baseline, sustained for ≥1 minute and/or requiring pharmacological or non-pharmacological intervention (e.g., atropine administration, reduction or discontinuation of the study drug). HR will be continuously monitored via standard intraoperative ECG monitoring and recorded at predefined time points: baseline (pre-induction), immediately post-induction (T1), at 5-minute intervals intraoperatively, at emergence from anesthesia, and at 15 and 30 minutes postoperatively in the post-anesthesia care unit (PACU). The incidence of bradycardia will be expressed as the proportion of patients experiencing at least one episode meeting the above criteria within the defined observation window.
Time frame: from enrollment up to 2 hours after the procedure; approximately 2-4 hours per participant.
Respiratory Stability - Oxygen Saturation (SpO₂)
Peripheral oxygen saturation (%) measured continuously via pulse oximetry. Comparison of SpO₂ values between study groups.
Time frame: from enrollment up to 2 hours after the procedure; approximately 2-4 hours per participant.
Incidence of Respiratory Depression
Percentage of participants experiencing respiratory depression defined as: Respiratory rate \<8 breaths per minute, AND/OR Peripheral oxygen saturation (SpO₂) \<90%
Time frame: from enrollment up to 2 hours after the procedure; approximately 2-4 hours per participant.
Procedural Sedation Success Rate
Percentage of participants achieving successful sedation defined as: Completion of entire endoscopic polypectomy procedure, AND No need for rescue sedation (defined as propofol 1.5-2.5 mg/kg IV by titration for inadequate sedation level in either group), AND Maximum of 5 additional drug doses within 15 minutes of initial dose
Time frame: During the endoscopic procedure (estimated 30-50 minutes
Time to Adequate Sedation Level
Time in minutes from first drug dose to achievement of adequate sedation level, defined as MOAA/S (Modified Observer's Assessment of Alertness/Sedation) score \<3 AND/OR BIS (Bispectral Index) value 50-70
Time frame: From first drug administration until adequate sedation achieved (estimated 1-5 minutes)
Time to Full Alertness
Time in minutes from last drug dose to full patient alertness, defined as achieving MOAA/S score of 5
Time frame: From last drug administration until full alertness (estimated 10-20 minutes post-procedure)
Time to Recovery Room Discharge Readiness
Time in minutes from last drug dose to patient meeting discharge criteria from recovery room using Modified Aldrete Scoring System
Time frame: From last drug administration until meeting discharge criteria (estimated 15-30 minutes post-procedure)
Depth of Sedation - BIS Values
Bispectral Index (BIS) values (0-100 scale) measured continuously to assess depth of sedation. Target range 50-70. Comparison of BIS values between study groups throughout procedure.
Time frame: From baseline through procedure completion until full alertness (estimated 30-60 minutes)
Depth of Sedation - MOAA/S Scores
Modified Observer's Assessment of Alertness/Sedation (MOAA/S) scores (0-5 scale) measured at baseline, after total drug dose (time zero), then every 30 seconds for 3 minutes. Target score \<3 for adequate sedation.
Time frame: Baseline, immediately after drug administration, then every 30 seconds for 3 minutes, then as clinically indicated during procedure
Total Drug Dosage
Total dose of remimazolam besilate (mg) administered during procedure in the intervention group and total dose of propofol (mg) administered during procedure in the control group. Total dose of sufentanil (micrograms) administered in both groups (0.2 mcg/kg initial dose)
Time frame: During procedure (estimated 30-50 minutes)
Procedure and sedation duration
Duration of sedation and colonoscopic polypectomy procedure in minutes
Time frame: From first drug administration to full alertness (estimated 30-60 minutes) From procedure start to procedure completion (estimated 30-50 minutes)
Total Crystalloid Infusion Volume
Total volume (mL) of Plasma-Lyte crystalloid solution administered during procedure
Time frame: During procedure and recovery (estimated 30-90 minutes)
Incidence of Post-Procedure Pain, nausea and vomiting
Percentage of participants experiencing pain, nausea or vomiting in the post-procedure period
Time frame: ost-procedure assessment before recovery room discharge (estimated 30-60 minutes after last drug dose)
Satisfaction Score
Patient-reported satisfaction with sedation procedure (VAS from 0-10) Endoscopist-reported satisfaction with sedation quality for procedure performance (VAS from 0-10)
Time frame: Post-procedure before recovery room discharge
Plan to share: Undecided — Individual participant data will not be shared due to regulatory, ethical, and practical constraints. Croatian healthcare data protection law (NN 14/19) and GDPR regulations mandate strict safeguarding of personal health information. The informed consent obtained from participants explicitly limits data use to this specific study and does not authorize sharing of individual-level data with external parties. Given the relatively small sample size (n=100) and the specific clinical context at a single tertiary center, there is meaningful risk of participant re-identification even with standard de-identification procedures. Additionally, our institution lacks the technical infrastructure for secure data repository management and controlled access mechanisms necessary for responsible IPD sharing. Resources for comprehensive data curation, security auditing, and long-term stewardship were not included in the study budget. However, we are committed to research transparency.
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Studies of the drug tested here: Remimazolam besilate
Clinical Hospital Centre Zagreb