Remifentanil Effect on Burst Suppression Ratio

NCT ID: NCT06237101

Last Updated: 2025-11-20

Study Results

Results pending

The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.

Basic Information

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Recruitment Status

RECRUITING

Clinical Phase

NA

Total Enrollment

20 participants

Study Classification

INTERVENTIONAL

Study Start Date

2024-03-01

Study Completion Date

2026-09-30

Brief Summary

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The goal of this clinical trial is to determine whether remifentanil has a facilitating effect on the generation of burst suppression by propofol in adult patients (18-60 years) candidates for elective surgery who require remifentanil and American Society of Anesthesiology (ASA) classification I or II. The main question it aims to answer are:

• To determine whether remifentanil has a facilitating effect on the generation of burst suppression by propofol.

Participants will undergo general anesthesia with remifentanil and propofol sequentially. After loss of consciousness, remifentanil will be adjusted to a medium or high concentration randomly and it will be determined at what concentration of propofol the burst suppressions are generated.

Then, the concentrations of propofol that generate burst suppression associated with either a medium or high concentration of remifentanil will be compared.

Detailed Description

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Subjects will enter the ward, after which an 18 G intravenous cannula will be installed and will be monitored under the routinely applied ASA standard. Frontal EEG activity will be recorded using an anesthetic depth monitor and a baseline EEG will be recorded for 120 seconds with eyes closed. Subjects will then be preoxygenated. Once the oxygen concentration at the end of expiration reaches 90%, the administration of remifentanil will begin, under the Minto pharmacological model, to reach an effect site concentration of 7.5 ng/mL. Once the remifentanil concentration is reached, the infusion of propofol will begin at a rate of 15 mg/kg/h using Base Primea Orchestra, until loss of consciousness (LOC) is achieved. LOC will be defined as loss of response to verbal and tactile stimulation, which will be corroborated every 30 seconds. After this, the propofol infusion will be maintained at the concentration at which the LOC occurred, based on Marsh's pharmacological model, and rocuronium 0.6 mg/kg will be administered to facilitate orotracheal intubation.

Once the patient has been intubated, the remifentanil will be lowered to a concentration of 4 ng/mL and the surgery will continue. After 5 min after the LOC occurred, according to randomization, the concentration of remifentanil will remain at 4 ng/mL or increase to 7.5 ng/mL, and 10 min after the LOC occurred the propofol infusion rate will be changed to 15 mg/kg/h for 10 min. After this, the propofol concentration at which the LOC occurred will be returned and remifentanil will be maintained at 4 ng/mL. After 5 min after completing the previous step, remifentanil will be increased to 7.5 ng/mL or maintained at 4 ng/mL in the opposite way to what happened previously. After 10 min after completing the previous step, propofol will be dosed again at a fixed rate of 15 mg/kg/h for 10 min. Finally, after this time has elapsed, the concentration of propofol at which the LOC occurred will be returned and the remifentanil will be dosed according to the surgical requirements. Throughout the protocol, hemodynamics will be maintained with the usual management of drugs such as ephedrine in boluses or norepinephrine in continuous infusion.

Conditions

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Anesthesia, Intravenous Electroencephalography Burst Suppression

Study Design

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Allocation Method

RANDOMIZED

Intervention Model

CROSSOVER

Primary Study Purpose

BASIC_SCIENCE

Blinding Strategy

SINGLE

Participants

Study Groups

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High dose

Propofol concentration which generate burst suppression at high dose of remifentanil

Group Type EXPERIMENTAL

High dose of remifentanil

Intervention Type DRUG

The dose of remifentanil will be changed to determine the concentration of propofol at which burst suppressions are generated

Medium dose

Propofol concentration which generate burst suppression at medium dose of remifentanil

Group Type ACTIVE_COMPARATOR

Medium dose of remifentanil

Intervention Type DRUG

The dose of remifentanil will be changed to determine the concentration of propofol at which burst suppressions are generated

Interventions

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High dose of remifentanil

The dose of remifentanil will be changed to determine the concentration of propofol at which burst suppressions are generated

Intervention Type DRUG

Medium dose of remifentanil

The dose of remifentanil will be changed to determine the concentration of propofol at which burst suppressions are generated

Intervention Type DRUG

Eligibility Criteria

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Inclusion Criteria

* American Society of Anesthesiology I or II
* Elective surgery of low or intermediate risk

Exclusion Criteria

* Neurological disease
* Psychiatric disease
* Use of psychoactive drugs or opioids
* Altered basal state of consciousness
* Allergy to propofol
* Body mass index \> 35 kg/m2
* Pre-existing renal, cardiac and/or hepatic dysfunction
* Patient's refusal to participate
Minimum Eligible Age

18 Years

Maximum Eligible Age

60 Years

Eligible Sex

ALL

Accepts Healthy Volunteers

No

Sponsors

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University of Chile

OTHER

Sponsor Role lead

Responsible Party

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Responsibility Role SPONSOR

Locations

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Centro de Investigación Cínica Avanzada (CICA), Hospital Clinico de la Universidad de Chile

Santiago, RM, Chile

Site Status RECRUITING

Hospital Clinico de la Universidad de Chile

Santiago, RM, Chile

Site Status RECRUITING

Countries

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Chile

Central Contacts

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Antonello Penna, MD, PhD

Role: CONTACT

+56229788209

Facility Contacts

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Daniela Ponce, Ing

Role: primary

56229789405

Other Identifiers

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OAIC: 1345/23

Identifier Type: -

Identifier Source: org_study_id

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