Response Surface Modeling of Remimazolam and Sevoflurane

May 27, 2026 updated by: Kim Hee Young, Pusan National University Yangsan Hospital

Response Surface Model Between Remimazolam and Sevoflurane; Comparison of the Minto and the Greco Model

This prospective randomized open-label study aims to investigate the pharmacodynamic interaction between remimazolam and sevoflurane during general anesthesia using response surface modeling. Although remimazolam has favorable hemodynamic stability compared with propofol, its hypnotic effect may be less predictable and poorly correlated with conventional sedation monitoring indices such as the bispectral index (BIS). In clinical practice, remimazolam and sevoflurane are often combined during induction and maintenance of anesthesia; however, the optimal interaction between these agents remains unclear.

This study will evaluate whether the interaction between remimazolam and sevoflurane is synergistic, additive, or infra-additive using two representative response surface interaction models: the Minto model and the Greco model. BIS values and predicted effect-site concentrations will be analyzed using NONMEM software.

Study Overview

Status

Status

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Recruiting

Conditions

Conditions

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Intervention / Treatment

Intervention / Treatment

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Detailed Description

Remimazolam is a recently developed ultra-short-acting benzodiazepine anesthetic with favorable pharmacokinetic characteristics, including a short context-sensitive decrement time and relatively stable hemodynamics. Despite these advantages, remimazolam may exhibit weaker hypnotic potency and inconsistent correlations with conventional anesthetic depth monitors such as BIS.

In current clinical practice, anesthesiologists frequently combine remimazolam with volatile anesthetics such as sevoflurane during induction or maintenance of anesthesia. However, the pharmacodynamic interaction between remimazolam and sevoflurane has not been fully elucidated.

The present study will investigate the interaction between remimazolam and sevoflurane using response surface modeling. The study will enroll adult patients undergoing elective laparoscopic surgery under general anesthesia. Various combinations of remimazolam infusion rates and end-tidal sevoflurane concentrations will be administered during anesthetic induction. BIS values and predicted effect-site concentrations will be collected and analyzed.

Pharmacodynamic interaction analyses will be performed using NONMEM nonlinear mixed-effects modeling software. Both the Minto interaction model and the Greco interaction model will be applied to determine whether the interaction between remimazolam and sevoflurane is synergistic, additive, or infra-additive.

Study Type

Study Type

Describes the nature of a clinical study. Study types include interventional studies (also called clinical trials), observational studies (including patient registries), and expanded access.
Interventional

Enrollment (Estimated)

Enrollment

The number of participants in a clinical study. The "anticipated" enrollment is the target number of participants that the researchers need for the study.
80

Phase

Phase

The stage of a clinical trial studying a drug or biological product, based on definitions developed by the U.S. Food and Drug Administration (FDA). The phase is based on the study's objective, the number of participants, and other characteristics. There are five phases: Early Phase 1 (formerly listed as Phase 0), Phase 1, Phase 2, Phase 3, and Phase 4. Not Applicable is used to describe trials without FDA-defined phases, including trials of devices or behavioral interventions.
  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact

The name and contact information for the person who can answer enrollment questions for a clinical study. Each location where the study is being conducted may also have a specific contact, who may be better able to answer those questions.
  • Name: Hee Young Kim, MD, PhD
  • Phone Number: 82-55-360-2129
  • Email: anekhy@gmail.com

Study Locations

  • South Korea
      • Yangsan, South Korea, 50612
        • Recruiting
        • Pusan National University Yangsan Hospital
        • Contact:

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Eligibility Criteria

The key requirements that people who want to participate in a clinical study must meet or the characteristics they must have. Eligibility criteria consist of both inclusion criteria (which are required for a person to participate in the study) and exclusion criteria (which prevent a person from participating). Types of eligibility criteria include whether a study accepts healthy volunteers, has age or age group requirements, or is limited by sex.

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Adults aged 20 to 80 years
  • Scheduled for elective surgery under general anesthesia at Pusan National University Yangsan Hospital
  • American Society of Anesthesiologists (ASA) physical status I or II
  • Able to provide written informed consent

Exclusion Criteria:

  • Known allergy to remimazolam or sevoflurane
  • Renal, hepatic, neuromuscular, or neurological disease
  • Use of medications affecting the central nervous system
  • Chronic psychoactive drug use
  • Ischemic heart disease
  • Pregnant women

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Basic Science
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm

Participant Group / Arm

A group or subgroup of participants in a clinical trial that receives a specific intervention/treatment, or no intervention, according to the trial's protocol.
Intervention / Treatment

Intervention / Treatment

A process or action that is the focus of a clinical study. Interventions include drugs, medical devices, procedures, vaccines, and other products that are either investigational or already available. Interventions can also include noninvasive approaches, such as education or modifying diet and exercise.
Experimental: Remimazolam and Sevoflurane Combination During Anesthetic Induction
Participants undergoing elective surgery under general anesthesia will receive varying combinations of remimazolam and sevoflurane during anesthetic induction to evaluate pharmacodynamic interactions using response surface modeling.
Drug: Remimazolam (Byfavo)
Remimazolam will be administered at infusion rates ranging from 0 to 6 mg/kg/h using an infusion pump with pharmacokinetic simulation software.
Drug: Sevoflurane (Volatile Anesthetic)
Sevoflurane will be administered by inhalation with targeted end-tidal concentrations between 0 and 2 vol%.

What is the study measuring?

Primary Outcome Measures

Primary Outcome Measures

In a clinical study's protocol, the planned outcome measure that is the most important for evaluating the effect of an intervention/treatment. Most clinical studies have one primary outcome measure, but some have more than one.
Outcome Measure
Measure Description
Time Frame
Interaction coefficient (α) between remimazolam and sevoflurane derived from the Minto response surface model
Time Frame: During anesthetic induction
The interaction coefficient (α) describing the pharmacodynamic interaction between remimazolam effect-site concentration and end-tidal sevoflurane concentration will be estimated using the Minto response surface model based on BIS values collected during anesthetic induction.
During anesthetic induction
Interaction parameter between remimazolam and sevoflurane derived from the Greco response surface model
Time Frame: During anesthetic induction
The pharmacodynamic interaction parameter describing the interaction between remimazolam effect-site concentration and end-tidal sevoflurane concentration will be estimated using the Greco response surface model based on BIS values collected during anesthetic induction.
During anesthetic induction

Secondary Outcome Measures

Secondary Outcome Measures

In a clinical study's protocol, a planned outcome measure that is not as important as the primary outcome measure for evaluating the effect of an intervention but is still of interest. Most clinical studies have more than one secondary outcome measure.
Outcome Measure
Measure Description
Time Frame
BIS response according to hypnotic combinations
Time Frame: During anesthetic induction
Bispectral Index (BIS) values will be continuously recorded during anesthetic induction according to predefined combinations of remimazolam effect-site concentration and end-tidal sevoflurane concentration. The BIS is a processed electroencephalographic monitoring scale ranging from 0 to 100, where lower values indicate deeper levels of hypnosis and higher values indicate lighter levels of sedation or consciousness.
During anesthetic induction
Loss of consciousness (LOC)
Time Frame: During anesthetic induction
Time to loss of consciousness during induction
During anesthetic induction
Recovery of consciousness (ROC)
Time Frame: During emergence from anesthesia
Time to recovery of consciousness
During emergence from anesthesia
Heart rate
Time Frame: Intraoperative period
Heart rate (beats per minute) will be recorded at 5-minute intervals during the intraoperative period.
Intraoperative period
Systolic blood pressure
Time Frame: Intraoperative period
Systolic blood pressure (mmHg) will be recorded at 5-minute intervals during the intraoperative period.
Intraoperative period
Mean blood pressure
Time Frame: Intraoperative period
Mean blood pressure (mmHg) will be recorded at 5-minute intervals during the intraoperative period.
Intraoperative period
Cardiac output
Time Frame: Intraoperative period
Cardiac output (L/min) will be recorded at 5-minute intervals during the intraoperative period.
Intraoperative period
Cardiac index
Time Frame: Intraoperative period
Cardiac index (L/min/m²) will be recorded at 5-minute intervals during the intraoperative period.
Intraoperative period
Stroke volume variation
Time Frame: Intraoperative period
Stroke volume variation (%) will be recorded at 5-minute intervals during the intraoperative period.
Intraoperative period
Pulse pressure variation
Time Frame: Intraoperative period
Pulse pressure variation (%) will be recorded at 5-minute intervals during the intraoperative period.
Intraoperative period
Peripheral oxygen saturation
Time Frame: Intraoperative period
Peripheral oxygen saturation (%) will be recorded at 5-minute intervals during the intraoperative period.
Intraoperative period

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Sponsor

The organization or person who initiates the study and who has authority and control over the study.
Pusan National University Yangsan Hospital

Investigators

Investigators

A researcher involved in a clinical study. Related terms include site principal investigator, site sub-investigator, study chair, study director, and study principal investigator.
  • Principal Investigator: Hee Young Kim, MD, PhD, Pusan National University Yangsan Hospital, Yangsan, South Korea

Publications and helpful links

The person responsible for entering information about the study voluntarily provides these publications. These may be about anything related to the study.

General Publications

Study record dates

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Study Major Dates

Study Start (Actual)

Study Start

The actual date on which the first participant was enrolled in a clinical study. The "anticipated" study start date is the date that the researchers think will be the study start date.
May 15, 2026

Primary Completion (Estimated)

Primary Completion

The date on which the last participant in a clinical study was examined or received an intervention to collect final data for the primary outcome measure. Whether the clinical study ended according to the protocol or was terminated does not affect this date. For clinical studies with more than one primary outcome measure with different completion dates, this term refers to the date on which data collection is completed for all the primary outcome measures. The "anticipated" primary completion date is the date that the researchers think will be the primary completion date for the study.
April 1, 2027

Study Completion (Estimated)

Study Completion

The date on which the last participant in a clinical study was examined or received an intervention/treatment to collect final data for the primary outcome measures, secondary outcome measures, and adverse events (that is, the last participant's last visit). The "anticipated" study completion date is the date that the researchers think will be the study completion date.
December 31, 2027

Study Registration Dates

First Submitted

First Submitted

The date on which the study sponsor or investigator first submitted a study record to ClinicalTrials.gov. There is typically a delay of a few days between the first submitted date and the record's availability on ClinicalTrials.gov (the first posted date).
May 14, 2026

First Submitted That Met QC Criteria

First Submitted That Met QC Criteria

The date on which the study sponsor or investigator first submits a study record that is consistent with National Library of Medicine (NLM) quality control (QC) review criteria. The sponsor or investigator may need to revise and submit a study record one or more times before NLM's QC review criteria are met. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
May 27, 2026

First Posted (Actual)

First Posted

The date on which the study record was first available on ClinicalTrials.gov after National Library of Medicine (NLM) quality control (QC) review has concluded. There is typically a delay of a few days between the date the study sponsor or investigator submitted the study record and the first posted date.
June 2, 2026

Study Record Updates

Last Update Posted (Actual)

Last Update Posted

The most recent date on which changes to a study record were made available on ClinicalTrials.gov. There may be a delay between when the changes were submitted to ClinicalTrials.gov by the study's sponsor or investigator (the last update submitted date) and the last update posted date.
June 2, 2026

Last Update Submitted That Met QC Criteria

Last Update Submitted That Met QC Criteria

The most recent date on which the study sponsor or investigator submitted changes to a study record that are consistent with National Library of Medicine (NLM) quality control (QC) review criteria. It is the responsibility of the sponsor or investigator to ensure that the study record is consistent with the NLM QC review criteria.
May 27, 2026

Last Verified

Last Verified

The most recent date on which the study sponsor or investigator confirmed the information about a clinical study on ClinicalTrials.gov as accurate and current. If a study with a recruitment status of recruiting; not yet recruiting; or active, not recruiting has not been confirmed within the past 2 years, the study's recruitment status is shown as unknown.
May 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

Other Study ID Numbers

Identifiers or ID numbers other than the NCT number that are assigned to a clinical study by the study's sponsor, funders, or others. These numbers may include unique identifiers from other trial registries and National Institutes of Health grant numbers.
  • 05-2023-090

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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