Anesthesia, IntravenousNCT06237101
Remifentanil Effect on Burst Suppression Ratio
A study testing High dose of remifentanil and Medium dose of remifentanil in people with Anesthesia, Intravenous and Electroencephalography, run by University of Chile at 2 sites in Chile.
Trial summary
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. Read more about this study
- Who is it for?
- Ages 18 to 60 years
- Conditions the study is for
- Anesthesia, Intravenous, Electroencephalography, Burst Suppression
- What is being tested?
- High dose of remifentanil and Medium dose of remifentanil
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 20 participants
- Where
- 2 sitesChile
- Study dates
- 1 Mar 2024to 30 Sep 2026
- Phase
- Interventional
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 60 years
- All sexes
- No healthy volunteers
- Adult
Who may be able to join
- American Society of Anesthesiology I or II
- Elective surgery of low or intermediate risk
Who cannot join
- 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
Trial locations and contacts
2 sites in 1 country. Contact the study team or a site near you to ask about taking part.
Chile2 sites, 2 recruiting
- Recruiting
Centro de Investigación Cínica Avanzada (CICA), Hospital Clinico de la Universidad de Chile
Santiago, RM, 7690306
Daniela Ponce, Ing, 56229789405, dponcedelavega@gmail.com
- Recruiting
Hospital Clinico de la Universidad de Chile
Santiago, RM, 7690306
About this study
Official title: Influence of Variable Plasma Concentrations of Remifentanil on Burst Suppression (BS) Event Rate in Electroencephalographic (EEG) Recordings of Human Subjects Undergoing Total Intravenous General Anesthesia (TIVA) Under Propofol
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.
Read more
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.
Read the detailed description
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.
- Being tested
- High dose of remifentanil, Medium dose of remifentanil
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
High dose of remifentanilDrug
The dose of remifentanil will be changed to determine the concentration of propofol at which burst suppressions are generated
Medium dose of remifentanilDrug
The dose of remifentanil will be changed to determine the concentration of propofol at which burst suppressions are generated
| Study group | Role | What they receive |
|---|---|---|
| High dose | Experimental | Propofol concentration which generate burst suppression at high dose of remifentanil Receives: Drug: High dose of remifentanil |
| Medium dose | Active comparator | Propofol concentration which generate burst suppression at medium dose of remifentanil Receives: Drug: Medium dose of remifentanil |
What is being measured
The primary outcome is the main question the study is designed to answer.
Propofol estimated concentration by Marsh pharmacological model, which generates burst suppression
[mcg/mL]
Measured: During 10 minutes when propofol dosification is increased to 15 mg/kg/h
Secondary outcomes (5)
Propofol estimated concentration by Marsh pharmacological model, which generates loss of consciousness
[mcg/mL]
Measured: Minutes, during anesthesia induction is performed
Mean arterial pressure during burst suppression
mmHg
Measured: During 10 minutes when propofol dosification is increased to 15 mg/kg/h
Total ephedrine dose
mg
Measured: During all protocol, 40 min
Maximal dose of norepinephrine
mcg/kg/min
Measured: During all protocol, 40 min
Bispectral index at burst suppression
(0-100), 0 indicates a flat electroencephalogram and 100 indicates to be awake.
Measured: During 10 minutes when propofol dosification is increased to 15 mg/kg/h
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted1 Feb 2024
- Study start1 Mar 2024
- Primary completion31 Aug 2026 (estimated)
- Study completion30 Sep 2026 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Anesthesia, IntravenousStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase N/A
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Single blind
- Who is masked
- Participant
- Enrolment
- 20 participants (estimated)
Sponsor and investigators
- Lead sponsor
- University of Chile
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06237101
- Sponsor's protocol ID
- OAIC: 1345/23
- Status last verified
- Oct 2025
- First submitted
- 24 Jan 2024
- Last updated
- 20 Nov 2025
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
Study at a glance
From the registry record, last updated by the sponsor on 20 Nov 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Influence of Variable Plasma Concentrations of Remifentanil on Burst Suppression (BS) Event Rate in Electroencephalographic (EEG) Recordings of Human Subjects Undergoing Total Intravenous General Anesthesia (TIVA) Under Propofol
- ClinicalTrials.gov ID
- NCT06237101
- Acronym / sponsor ID
- OAIC: 1345/23
- Study type
- Interventional
- Recruitment status
- Recruiting
- Enrolment
- 20 participants (estimated)
- Lead sponsor
- University of ChileUniversity, hospital or other
- Study start
- 1 Mar 2024 (actual)
- Primary completion
- 31 Aug 2026 (estimated)
- Study completion
- 30 Sep 2026 (estimated)
- First posted
- 1 Feb 2024 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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
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.
Study design
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Crossover
- Masking
- Single blind (participant)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| High dose | Experimental | Drug: High dose of remifentanilPropofol concentration which generate burst suppression at high dose of remifentanil |
| Medium dose | Active comparator | Drug: Medium dose of remifentanilPropofol concentration which generate burst suppression at medium dose of remifentanil |
Who may qualify
- Ages
- 18 to 60 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult
Key inclusion criteria (2 listed)
- American Society of Anesthesiology I or II
- Elective surgery of low or intermediate risk
Key exclusion criteria (8 listed)
- Neurological disease
- Psychiatric disease
- Use of psychoactive drugs or opioids
- Altered basal state of consciousness
- Allergy to propofol
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| High dose of remifentanilThe dose of remifentanil will be changed to determine the concentration of propofol at which burst suppressions are generated | Drug | High dose |
| Medium dose of remifentanilThe dose of remifentanil will be changed to determine the concentration of propofol at which burst suppressions are generated | Drug | Medium dose |
Primary outcome
Propofol estimated concentration by Marsh pharmacological model, which generates burst suppression
Time frame: During 10 minutes when propofol dosification is increased to 15 mg/kg/h
[mcg/mL]
5 secondary outcomes
Propofol estimated concentration by Marsh pharmacological model, which generates loss of consciousness
Time frame: Minutes, during anesthesia induction is performed
Mean arterial pressure during burst suppression
Time frame: During 10 minutes when propofol dosification is increased to 15 mg/kg/h
Total ephedrine dose
Time frame: During all protocol, 40 min
Maximal dose of norepinephrine
Time frame: During all protocol, 40 min
Bispectral index at burst suppression
Time frame: During 10 minutes when propofol dosification is increased to 15 mg/kg/h
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 20 Nov 2025.
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
2 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A study testing High dose of remifentanil and Medium dose of remifentanil in people with Anesthesia, Intravenous and Electroencephalography, run by University of Chile at 2 sites in Chile.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 2 inclusion and 8 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: looking for participants now, as of the sponsor's last update on 20 Nov 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 2 sites in Chile. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
Contact Antonello Penna, MD, PhD (+56229788209, apenna@uchile.cl), or a site near the patient. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Propofol estimated concentration by Marsh pharmacological model, which generates burst suppression (time frame: During 10 minutes when propofol dosification is increased to 15 mg/kg/h). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 20 Nov 2025.