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NCT Number: NCT07699523

The Effects of Midazolam, Dexmedetomidine, and Esketamine on Bispectral Index and Raw Electroencephalogram in Patients Under Propofol-Remifentanil Baseline Anesthesia

This prospective, single-center, randomized interventional study aims to investigate the effects of commonly used adjunct anesthetic drugs on the Bispectral Index (BIS) and electroencephalographic (EEG) activity during total intravenous anesthesia.

BIS monitoring is widely used to estimate the depth of anesthesia. However, previous studies suggest that certain anesthetic drugs, particularly dexmedetomidine and esketamine, may alter BIS values independently of the patient's actual level of consciousness. As a result, BIS readings may not always accurately reflect anesthetic depth when multiple drugs are administered together.

Adult patients undergoing elective laparoscopic cholecystectomy under standardized propofol-remifentanil anesthesia will be randomly assigned to receive one of the following adjunct drugs: midazolam, dexmedetomidine, esketamine, or no additional study drug (control group). Continuous BIS values and raw EEG signals will be recorded throughout the study period.

The primary objective is to compare changes in BIS values among different adjunct anesthetic drugs under otherwise similar anesthetic conditions. The study will also explore corresponding EEG characteristics associated with these changes. The findings are expected to improve understanding of drug-related differences in processed EEG monitoring and provide data for future development of more accurate anesthesia depth assessment methods.

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Key information

Conditions

Depth of Anesthesia Monitoring BIS-EEG

Age range

18 year–65 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Primary location

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • ASA physical status I-II;
  • BMI 18-28 kg/m²;
  • Scheduled for elective laparoscopic cholecystectomy, with an expected surgical duration from skin incision to completion of wound closure of ≥45 min;
  • Planned to receive propofol-remifentanil total intravenous anesthesia, with routine intraoperative BIS monitoring and simultaneous acquisition of raw EEG signals;
  • Voluntarily agrees to participate in this study, has signed the informed consent form, and is able to cooperate with the intervention and assessment procedures.

Exclusion criteria

  • A confirmed history of psychiatric or neurological disorders, or use of antipsychotics, antidepressants, benzodiazepines, or other sedative-hypnotic drugs within 4 weeks before surgery;
  • Cognitive impairment identified by Mini-Cog screening;
  • Poorly controlled or untreated hypertension, sinus bradycardia, or severe cardiac conduction block;
  • Acute angle-closure glaucoma;
  • Known allergy to any required anesthetic drug;
  • Difficulty in electrode placement or any condition that may interfere with EEG monitoring.

Treatment and study plan

midazolam

Drug

Midazolam administered as an adjunct to standardized propofol-remifentanil total intravenous anesthesia according to the study protocol.

Dexmedetomidine

Drug

Dexmedetomidine administered as an adjunct to standardized propofol-remifentanil total intravenous anesthesia according to the study protocol.

Esketamine

Drug

Esketamine administered as an adjunct to standardized propofol-remifentanil total intravenous anesthesia according to the study protocol.

Propofol

Drug

Propofol will be administered as part of standardized total intravenous anesthesia in all study groups.

Remifentanil

Drug

Remifentanil will be administered as part of standardized total intravenous anesthesia in all study groups.

Primary outcomes

  1. Change in Bispectral Index (BIS) value from the pre-intervention baseline

    Time frame: Baseline and 5, 10, 15, 20, 25, 30 minutes after adjunct drug administration

    Change in Bispectral Index value from the stable pre-intervention baseline will be compared among the four study groups after administration of the assigned adjunct anesthetic drug under standardized propofol-remifentanil total intravenous anesthesia. The pre-intervention baseline is defined as the stable BIS value immediately before administration of the assigned adjunct anesthetic drug. The Bispectral Index is a dimensionless electroencephalography-derived index ranging from 0 to 100, with lower values indicating deeper hypnotic states.

Secondary outcomes

  1. Change in mean arterial pressure from pre-intervention baseline

    Time frame: Baseline and 5, 10, 15, 20, 25, and 30 minutes after adjunct drug administration.

    Change in mean arterial pressure (MAP) from the stable pre-intervention baseline will be compared among the four study groups after administration of the assigned adjunct anesthetic drug under standardized propofol-remifentanil total intravenous anesthesia.

  2. Change in heart rate from pre-intervention baseline

    Time frame: Baseline and 5, 10, 15, 20, 25, and 30 minutes after adjunct drug administration.

    Change in heart rate (HR) from the stable pre-intervention baseline will be compared among the four study groups after administration of the assigned adjunct anesthetic drug.

  3. Time from discontinuation of anesthetic drugs to airway device removal

    Time frame: From discontinuation of anesthetic drugs to airway device removal, up to 60 minutes.

    The time interval from discontinuation of anesthetic drugs to removal of the airway device will be recorded.

  4. Time to Aldrete score of 10 in the post-anesthesia care unit

    Time frame: From admission to the post-anesthesia care unit to achievement of an Aldrete score of 10, up to 2 hours.

    The time from admission to the post-anesthesia care unit to achievement of an Aldrete score of 10 will be recorded. The Aldrete score ranges from 0 to 10, with higher scores indicating better post-anesthesia recovery.

  5. Brice questionnaire assessment

    Time frame: Before discharge from the post-anesthesia care unit, and at 24 and 48 hours after surgery.

    The Brice questionnaire will be used to assess postoperative recall and awareness-related events.

  6. Postoperative pain score

    Time frame: At admission to the post-anesthesia care unit, before discharge from the post-anesthesia care unit, and at 24 and 48 hours after surgery.

    Postoperative pain intensity will be assessed using the numeric rating scale (NRS).

  7. Postoperative analgesic medication use

    Time frame: From admission to the post-anesthesia care unit to 48 hours after surgery.

    Use of postoperative analgesic medications, including opioid and non-opioid analgesics (e.g., NSAIDs), in the post-anesthesia care unit and hospital ward will be recorded and compared among study groups.

Other outcomes

  1. Change in pre-specified electroencephalographic spectral features from baseline

    Time frame: Baseline and 5, 10, 15, 20, 25, and 30 minutes after adjunct drug administration.

    Pre-specified electroencephalographic spectral features, including alpha-to-delta power ratio, frontal alpha power, alpha peak frequency, and burst suppression ratio, will be evaluated and compared among study groups at baseline and after administration of the assigned adjunct anesthetic drug.

  2. Change in electroencephalographic relative spectral power from baseline

    Time frame: Baseline and 5, 10, 15, 20, 25, and 30 minutes after adjunct drug administration.

    Relative power spectral density of delta, theta, alpha, beta, and gamma frequency bands will be compared among study groups at baseline and after administration of the assigned adjunct anesthetic drug.

Study contacts

Contact information is provided by the study sponsor or research team.

Li

CONTACT

[email protected]

+86-15811578082

Sponsors and collaborators

Lead sponsor

China-Japan Friendship Hospital

Other

Registry information

Important dates

Study start
2026
Primary completion
2027
Study completion
2027
First posted
Jul 13, 2026
Registry last updated
Jul 13, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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