Ciprofol and Remimazolam for Intraoperative Neurophysiological Monitoring During Spine Surgery (CIRIONM)

July 17, 2026 updated by: Jiawei Jiang, Affiliated 2 Hospital of Nantong University

Effects of Alternating Ciprofol and Remimazolam on Intraoperative Motor and Somatosensory Evoked Potentials During Spine Surgery: A Randomized Crossover Trial

Intraoperative neurophysiological monitoring, including motor evoked potentials and somatosensory evoked potentials, is commonly used during spine surgery to help detect impending neurological injury. The quality of these signals can be affected by anesthetic agents. Ciprofol and remimazolam are newer intravenous hypnotic agents that may be suitable for total intravenous anesthesia during procedures requiring neurophysiological monitoring, but direct within-patient comparisons between the two agents are lacking. This single-center, prospective, randomized, two-sequence crossover trial will compare the effects of ciprofol and remimazolam, administered with remifentanil, on intraoperative MEP and SEP signal quality during spine surgery. Eligible participants will be randomized to receive either ciprofol followed by remimazolam or remimazolam followed by ciprofol during predefined stable intraoperative monitoring windows. The primary outcome is the within-participant difference in lower-extremity MEP peak-to-peak amplitude between the ciprofol and remimazolam periods. Secondary outcomes include SEP amplitude and latency, MEP latency, warning-threshold events, hemodynamic variables, rescue medication requirements, recovery characteristics, and postoperative neurological status.

Study Overview

Status

Status

Indicates the current recruitment status or the expanded access status.
Not yet recruiting

Conditions

Conditions

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Intervention / Treatment

Intervention / Treatment

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Detailed Description

MEP and SEP monitoring are important components of intraoperative neurophysiological monitoring during complex spine surgery. However, evoked potential amplitudes and latencies are influenced not only by neurological injury but also by anesthetic depth, hypnotic agents, opioids, blood pressure, temperature, carbon dioxide, residual neuromuscular blockade, stimulation parameters, patient positioning, and surgical stage. Total intravenous anesthesia is therefore commonly preferred when reliable MEP monitoring is required. Ciprofol is a propofol analogue acting mainly on GABAA receptors and may provide sedation or anesthesia with less circulatory depression in some settings. Remimazolam is a short-acting benzodiazepine metabolized by tissue esterases and can be antagonized by flumazenil. Existing studies have compared each drug with propofol or reported successful MEP monitoring under remimazolam, but there is no direct randomized crossover comparison of ciprofol and remimazolam during spine surgery requiring MEP and SEP monitoring. In this trial, each participant will serve as his or her own control. Participants will be randomized in a 1:1 ratio to one of two sequences: ciprofol followed by remimazolam or remimazolam followed by ciprofol. Both study periods will be conducted under remifentanil-based analgesia and similar targets for anesthetic depth, hemodynamics, ventilation, temperature, and neuromuscular recovery. MEP and SEP recordings will be obtained during stable intraoperative windows before and after drug transition. The study aims to determine whether one agent provides more favorable neurophysiological monitoring signal quality while maintaining acceptable hemodynamic stability and surgical conditions.

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.
60

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.
  • Phase 4

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:

  1. Age 18 to 75 years.
  2. Scheduled to undergo elective spine surgery.
  3. Planned intraoperative monitoring with MEP and SEP/SSEP.
  4. Expected surgical duration sufficient to complete two study drug periods and intraoperative monitoring windows, preferably at least 3.5 to 4 hours.
  5. American Society of Anesthesiologists physical status I to III.
  6. Able to provide written informed consent, or consent provided by a legally authorized representative where applicable.

Exclusion Criteria:

  1. Known allergy or contraindication to ciprofol, remimazolam, benzodiazepines, propofol-related formulations, opioids, or relevant excipients.
  2. Severe preoperative motor or sensory deficit preventing interpretable target MEP or SEP baseline recordings.
  3. Implanted cardiac pacemaker, skull defect, or other condition considered unsuitable for transcranial electrical stimulation.
  4. Severe neuromuscular disease, poorly controlled epilepsy, severe cognitive impairment, or inability to complete postoperative neurological assessment.
  5. Severe hepatic or renal dysfunction, severe hemodynamic instability, shock, or requirement for high-dose vasoactive medications before enrollment.
  6. Long-term benzodiazepine, sedative-hypnotic, antiepileptic drug use, or drug/alcohol dependence that may substantially alter anesthetic response.
  7. Expected need for continuous deep neuromuscular blockade during surgery, preventing valid MEP monitoring.
  8. Any other condition judged by the investigators to make participation unsuitable or unsafe.

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: Supportive Care
  • Allocation: Randomized
  • Interventional Model: Crossover Assignment
  • Masking: Single

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: Ciprofol-Remimazolam Sequence
Participants assigned to this sequence will receive ciprofol-based total intravenous anesthesia during the first stable intraoperative monitoring period. After the predefined first-period MEP and SEP recordings are completed, the hypnotic agent will be switched to remimazolam. After an approximately 45- to 60-minute stabilization and washout period, second-period MEP and SEP recordings will be obtained under remimazolam-based anesthesia. Remifentanil analgesia and standard physiologic targets will be maintained as consistently as clinically feasible across both periods.
Drug: Ciprofol
Ciprofol will be administered intravenously for induction and/or maintenance according to the institutional anesthesia protocol and product labeling. A suggested maintenance range is approximately 0.8 to 1.5 mg/kg/h, adjusted according to anesthetic depth, hemodynamics, surgical conditions, and patient safety.
Drug: Remimazolam
Remimazolam will be administered intravenously for induction and/or maintenance according to the institutional anesthesia protocol and product labeling. A suggested maintenance range is approximately 0.5 to 2 mg/kg/h or 1 to 2 mg/kg/h, adjusted according to anesthetic depth, hemodynamics, surgical conditions, body movement, and patient safety.
Experimental: Remimazolam-Ciprofol Sequence
Participants assigned to this sequence will receive remimazolam-based total intravenous anesthesia during the first stable intraoperative monitoring period. After the predefined first-period MEP and SEP recordings are completed, the hypnotic agent will be switched to ciprofol. After an approximately 45- to 60-minute stabilization and washout period, second-period MEP and SEP recordings will be obtained under ciprofol-based anesthesia. Remifentanil analgesia and standard physiologic targets will be maintained as consistently as clinically feasible across both periods.
Drug: Ciprofol
Ciprofol will be administered intravenously for induction and/or maintenance according to the institutional anesthesia protocol and product labeling. A suggested maintenance range is approximately 0.8 to 1.5 mg/kg/h, adjusted according to anesthetic depth, hemodynamics, surgical conditions, and patient safety.
Drug: Remimazolam
Remimazolam will be administered intravenously for induction and/or maintenance according to the institutional anesthesia protocol and product labeling. A suggested maintenance range is approximately 0.5 to 2 mg/kg/h or 1 to 2 mg/kg/h, adjusted according to anesthetic depth, hemodynamics, surgical conditions, body movement, and patient safety.

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
Within-participant difference in lower-extremity MEP peak-to-peak amplitude between ciprofol and remimazolam periods
Time Frame: During surgery, at predefined stable monitoring windows under each study drug; up to 6 hours
Lower-extremity target-muscle motor evoked potential peak-to-peak amplitudes will be recorded during stable intraoperative monitoring windows under ciprofol and remimazolam. The primary analysis will compare log-transformed MEP amplitude or amplitude ratio between the two drug periods within the same participant.
During surgery, at predefined stable monitoring windows under each study drug; up to 6 hours

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
Within-participant difference in lower-extremity SEP amplitude
Time Frame: During surgery, at predefined stable monitoring windows under each study drug; up to 6 hours
Lower-extremity somatosensory evoked potential amplitudes will be compared between the ciprofol and remimazolam periods.
During surgery, at predefined stable monitoring windows under each study drug; up to 6 hours

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.
Affiliated 2 Hospital of Nantong University

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Estimated)

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.
August 1, 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.
December 1, 2026

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.
January 1, 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).
July 17, 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.
July 17, 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.
July 21, 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.
July 21, 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.
July 17, 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.
July 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.
  • 2026-KT253

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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