Effect of Drug
Conditions
Brief summary
The aim of this prospective dose-finding study is to determine the ED50 of propofol required for successful colonoscope insertion in adult 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 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. 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.
Interventions
DRUGPropofol
The initial dose is 1.5 mg/kg, adjusted in increments or decrements of 0.1 mg/kg according to the modified Dixon's up-and-down method. Additional rescue doses of 0.25-0.5 mg/kg is titrated if insertion is unsuccessful.
Sponsors
Kocaeli City Hospital
Study design
Allocation
NA
Intervention model
SINGLE_GROUP
Primary purpose
TREATMENT
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
18 Years to 65 Years
Healthy volunteers
No
Inclusion criteria
* Patients who provided informed consent to participate * Patients scheduled for colonoscopy * ASA physical status I-III * Male and female patients aged 18-65 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
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| 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
| Measure | Time frame | Description |
|---|---|---|
| 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 (start of procedure); 2 minutes after insertion; and at the end of the procedure (completion of colonoscopy). | Hemodynamic parameters will be recorded at the specified time points to evaluate physiological stability during the procedure. |
| 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. |
| SpO2 | Baseline (before sedation); at colonoscope insertion (start of procedure); 2 minutes after insertion; and at the end of the procedure (completion of colonoscopy). | 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. |
| mean arterial pressure | Baseline (before sedation); at colonoscope insertion (start of procedure); 2 minutes after insertion; and at the end of the procedure (completion of colonoscopy). | Hemodynamic parameters will be recorded at the specified time points to evaluate physiological stability during the procedure. |
Countries
Turkey (Türkiye)
Outcome results
None listed