Propofol Dose-Finding for Colonoscope Insertion in Geriatric Patients

Not Applicable

Recruiting

• Conditions: Effect of Drug
• Interventions: Drug: Propofol

• Registration Number: NCT07162805
• Lead Sponsor: Kocaeli City Hospital

Brief Summary

The aim of this prospective dose-finding study is to determine the ED50 of propofol required for successful colonoscope insertion in geriatric patients. The study is designed using Dixon's up-and-down sequential allocation method. Successful colonoscope insertion is defined as the absence of pain, movement, or vocal response, together with a MOAA/S score ≤2 at the second minute after induction, and maintained until the colonoscope pass the rectosigmoid junction. In cases of failure, an additional dose of propofol is administered, and the initial dose for the next patient was increased by 0.1 mg/kg. In cases of success, the initial dose for the next patient was decreased by 0.1 mg/kg.

The primary outcome is the determination of the ED50 of propofol for successful colonoscope insertion until passage of the rectosigmoid junction.

Detailed Description

The procedure is performed by an experienced endoscopist. If, during passage of the colonoscope through the rectosigmoid junction, the patient moves, experiences pain, vocalizes, or if the MOAA/S score is ≥3 at the second minute after induction, the insertion is defined as unsuccessful, and an additional rescue dose of 0.25-0.5 mg/kg propofol is titrated intravenously. The initial propofol dose for the next patient is then increased by 0.1 mg/kg.

If there is no movement during passage of the rectosigmoid junction, the patient reports no pain, and the MOAA/S score is ≤2 at the second minute after induction, the insertion is defined as successful, and the initial dose for the next patient is decreased by 0.1 mg/kg.

The conditions for colonoscope insertion are evaluated only at the initial attempt. If, after the start of the procedure, the patient experiences pain, moves, vocalizes, or the MOAA/S score is ≥3, an additional dose of 0.25-0.5 mg/kg propofol is titrated as required.

Throughout the procedure, the target is to maintain a MOAA/S score ≤2, which is systematically assessed at 2-minute intervals. Vital signs, procedure duration, and drug dosages are recorded for all patients.

At the end of the procedure, patients are awakened with verbal and tactile stimuli. After completion of colonoscopy, all patients are transferred to the post-anesthesia care unit for close monitoring until achieving a Modified Aldrete score of 10. Patients with a Modified Aldrete score of 10 are discharged.

Study Timeline

• Study First Submitted: 2025-08-25
• Study First Submitted QC: 2025-08-30
• Status Verified: 2025-09
• Study Start: 2025-09-08
• Study First Posted: 2025-09-09
• Last Update Submitted: 2025-09-21
• Last Update Posted: 2025-09-23
• Primary Completion: 2025-09-30
• Study Completion: 2025-09-30

Recruitment & Eligibility

• Status: RECRUITING
• Sex: All
• Target Recruitment: 30

Inclusion Criteria

• Patients who provided informed consent to participate
• Patients scheduled for colonoscopy
• ASA physical status I-III
• Male and female patients aged ≥65 years

Exclusion Criteria

• Patients who did not provide consent
• Known allergy to propofol
• Body weight <40 kg
• Body mass index (BMI) >30 kg/m²
• Presence of acute or chronic pain
• Chronic alcohol consumption
• Use of antipsychotic, antidepressant, or hypnotic medications
• Patients with obstructive sleep apnea syndrome (STOP-Bang score ≥3)
• Patients with known anorectal diseases such as hemorrhoids, anal fissure, or anal fistula
• History of oncological disease
• Uncontrolled hypertension (blood pressure >180/110 mmHg)
• Severe hepatic or renal dysfunction
• Acute respiratory tract infection or other chronic respiratory disorders
• Patients with a history of colorectal surgery

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: SINGLE_GROUP

Arm && Interventions

Group	Intervention	Description
Group mono-Propofol	Propofol	The study is designed using Dixon's up-and-down sequential allocation method. Successful colonoscope insertion is defined as the absence of pain, movement, or vocal response, together with a MOAA/S score ≤2 at the second minute after induction, and maintained until the colonoscope passes the rectosigmoid junction. In cases of failure, an additional dose of propofol is administered, and the initial dose for the next patient is increased by 0.1 mg/kg. In cases of success, the initial dose for the next patient is decreased by 0.1 mg/kg.

Primary Outcome Measures

Name	Time	Method
ED50	At 2 minutes after induction (during colonoscope insertion)	The median effective dose (ED50) of propofol required for successful colonoscope insertion in geriatric patients will be determined using the modified Dixon's up-and-down method. Successful insertion is defined as the absence of movement or vocalization and a MOAA/S score ≤2 within 2 minutes after induction, maintained until the colonoscope passes the rectosigmoid junction.

Secondary Outcome Measures

Name	Time	Method
ED95	At 2 minutes after induction (during colonoscope insertion)	The median effective dose (ED95) of propofol required for successful colonoscope insertion in geriatric patients will be determined using the modified Dixon's up-and-down method. Successful insertion is defined as the absence of movement or vocalization and a MOAA/S score ≤2 within 2 minutes after induction, maintained until the colonoscope passes the rectosigmoid junction.
Additional propofol dose	The cumulative amount of rescue propofol administered during the procedure will be recorded.	After induction until the end of the colonoscopy procedure
total propofol dose	The cumulative amount of total propofol administered during the procedure will be recorded.	From induction until the end of the colonoscopy procedure
Presence of pain during propofol injection	Immediately after first propofol administration	Pain during propofol injection will be assessed as a binary variable (Yes/No), evaluated immediately after the first propofol injection. Presence of pain = Yes, Absence of pain = No.
Heart rate	Baseline (before sedation), at colonoscope insertion, 2 minutes after insertion, and at the end of the procedure	Hemodynamic parameters will be recorded at the specified time points to evaluate physiological stability during the procedure.
mean arterial pressure	Baseline (before sedation), at colonoscope insertion, 2 minutes after insertion, and at the end of the procedure	Hemodynamic parameters will be recorded at the specified time points to evaluate physiological stability during the procedure.
SpO₂	Baseline (before sedation), at colonoscope insertion, 2 minutes after insertion, and at the end of the procedure	oxygen saturation parameter will be recorded at the specified time points to evaluate physiological stability during the procedure.
Procedure interruptions due to airway interventions	Throughout the colonoscopy procedure	The incidence of airway interventions (chin lift, jaw thrust, mask ventilation) and associated procedural interruptions will be recorded.
Minimum SpO₂ value during the procedure	Throughout the colonoscopy procedure	The lowest SpO₂ value observed during the procedure will be documented.

Trial Locations

Locations (1)

University of Health Sciences Kocaeli City Hospital; Kocaeli, Izmit, Turkey (Türkiye)