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Patient‑controlled propofol versus alfentanil and midazolam sedation for adenoma patients undergoing diagnostic and therapeutic colonoscopy: a satisfaction study

Verified siteRegistered drugNo placebo
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What is this trial about?

A plain-language summary of the goals, design and what participants do

The study focuses on people undergoing diagnostic or therapeutic Adenoma removal during colonoscopy, a procedure that looks inside the large intestine to find and treat abnormal growths. The sedation method being tested uses a patient‑controlled system that delivers the drug propofol through a vein (intravenous) to keep the person comfortable and relaxed. This is compared with the standard sedation that uses the drugs alfentanil and midazolam, also given intravenously. The main goal is to see whether the patient‑controlled approach leads to higher satisfaction with the experience.

Participants will receive the assigned sedation during their colonoscopy and will be asked to complete a short questionnaire after the procedure to report how satisfied they felt. The study will also record how much medication was used, how long the procedure and recovery lasted, and any side effects or problems that occur. After the colonoscopy, participants will be monitored until they are fully awake and able to go home, and the overall success of completing the procedure will be noted.

The research process

The trial runs in 9 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Enrollment and consent

    After joining the study, you will be asked to read and sign a consent form that explains the purpose of the trial and the procedures involved.

  2. Step 2

    Pre‑procedure assessment

    A brief medical interview and a few basic measurements (such as blood pressure and heart rate) will be taken to confirm that you are eligible for the colonoscopy and the sedation methods used in the trial.

  3. Step 3

    Preparation for colonoscopy

    You will be instructed to fast for a short period before the procedure. on the day of the colonoscopy you will be taken to a procedure room where the equipment is prepared.

  4. Step 4

    Sedation administration

    The trial compares two sedation approaches. in the patient‑controlled propofol group, a total dose of 750 mg of propofol will be given through an intravenous line as a bolus injection and, if needed, a continuous infusion. you will be able to press a button to receive additional small doses of propofol during the colonoscopy.

    In the standard‑sedation group, you will receive alfentanil (1 mg) and midazolam (20 mg) by intravenous injection. these medicines are used to keep you comfortable and relaxed during the procedure.

  5. Step 5

    Colonoscopy procedure

    Once adequate sedation is achieved, the doctor will perform the colonoscopy to examine the colon and, if necessary, treat any adenomas that are found.

  6. Step 6

    Monitoring during the procedure

    Your vital signs (such as heart rate, blood pressure, and oxygen level) will be continuously monitored while you are sedated.

  7. Step 7

    Recovery period

    After the colonoscopy, the intravenous line will be removed and you will be observed in a recovery area until you are fully awake and able to sit up safely. the length of this recovery time will be recorded.

  8. Step 8

    Patient satisfaction questionnaire

    Once you feel comfortable, you will be asked to complete a short questionnaire that measures your satisfaction with the sedation experience.

  9. Step 9

    Study completion

    The information collected during the procedure, recovery, and questionnaire will be entered into the study database. no further study visits are required after this point.

Who can join the trial?

5 criteria

  • Be scheduled for a planned (elective diagnostic colonoscopy) using propofol sedation, or a planned (elective therapeutic colonoscopy) where the doctor may treat any problem found during the exam.
  • Be 18 years of age or older.
  • Be able to understand the study information and give written informed consent (sign a form that shows you agree to join the study).
  • Have an American Society of Anesthesiologists (ASA) physical status classification I–II, which means you are either healthy or have only mild health problems.
  • Be able to understand and use the patient‑controlled sedation device (a machine that lets you press a button to receive a small dose of medication) and complete the study questionnaires.

Who cannot join the trial?

7 criteria

  • If your overall health is rated as ASA physical status classification III or higher (meaning you have moderate to severe systemic disease).
  • If you have a known hypersensitivity (allergy) or a medical reason to avoid propofol or any ingredient (called an excipient) in the medication.
  • If you are pregnant or breastfeeding.
  • If you are unable to give valid informed consent (you cannot understand the study well enough to agree to take part).
  • If you have significant cognitive impairment (memory or thinking problems), severe psychiatric illness (serious mental health condition), or any other condition that would make it hard to participate reliably or complete questionnaires.
  • If you cannot understand the study procedures or do not speak the required language well enough and there is no support available to help you.
  • If you have a history of a serious adverse reaction or complication related to sedation or anesthesia (medicines used to make you sleepy for procedures).
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Investigated drugs

  • Propofol

    is the medication being tested in this study. It is given through an IV line either as a quick injection or as a continuous drip. In the trial, patients can control the amount they receive while they are having an endoscopic procedure. The purpose is to see if letting patients adjust their own propofol sedation makes them feel more satisfied with the experience compared with the usual sedation methods.

  • Alfentanil

    is one of the standard drugs used for comparison in the study. It is also given by IV injection. Alfentanil is a short‑acting pain reliever that helps keep patients comfortable and reduces pain during the endoscopic procedure. The trial uses it as a typical sedation option to compare against the patient‑controlled propofol approach.

  • Midazolam

    is another commonly used sedative that serves as a comparator in this trial. It is administered intravenously and works by calming patients and causing mild sleepiness, making the endoscopic procedure easier to tolerate. The study includes midazolam to represent the usual sedation practice against which the new patient‑controlled propofol method is evaluated.

What is already known about the treatment

  • PROPOFOL

    Administered as an intravenous bolus or continuous infusion, propofol is a short‑acting anesthetic that is approved and widely used for induction and maintenance of general anesthesia and for procedural sedation. It works by enhancing the activity of the brain’s GABA‑A receptors, which slows nerve signals and produces a rapid loss of consciousness. In medical literature it is well‑studied, with many clinical trials confirming its safety and effectiveness for sedation during endoscopic procedures. Pharmacologically it is classified as a short‑acting intravenous anesthetic agent.

  • ALFENTANIL

    Given by intravenous injection, alfentanil is an approved synthetic opioid used for short‑duration analgesia and sedation during surgery or diagnostic procedures. It binds to mu‑opioid receptors in the nervous system, reducing the perception of pain and producing a calm state. The drug is well documented in the medical literature as a fast‑acting opioid with a brief effect, making it useful for brief procedures. It belongs to the pharmacological class of short‑acting synthetic opioid analgesics.

  • MIDAZOLAM

    Midazolam is administered intravenously for rapid onset of sedation, anxiety relief, and memory loss during medical procedures. It is an approved benzodiazepine that enhances GABA‑A receptor activity, increasing inhibitory signals in the brain to produce calmness and drowsiness. Extensive clinical use and research support its safety and effectiveness for procedural sedation and pre‑operative anxiety. It is classified as a short‑acting benzodiazepine sedative.

Investigated diseases

Adenoma - Adenoma is a noncancerous growth that arises from glandular tissue in the digestive tract. It is usually small and may cause no symptoms, but it can be detected during endoscopy or imaging. Over time, some adenomas develop abnormal cells and may enlarge. If the abnormal cells increase, the adenoma can progress to a malignant tumor called adenocarcinoma. Monitoring is important because the risk of progression varies with size and cellular changes.
Trial detailsLast updated 2 Oct 2026
Age18+ yearsPhasePhase IIITrial ID2025-524859-31-00Estimated enrolment175 patientsSponsorKarolinska Institutet

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