COmparison of Maintenance of Propofol And Sevoflurane Spectral Study (COMPASS)

Comparison of EEG Power Spectrum During Maintenance of Anesthesia With Propofol Versus Sevoflurane

Lower EEG alpha band power is currently extensively studied as a potential biomarker of brain vulnerability. No previous study has evaluated whether there was a difference in EEG power spectrum ranges between propofol and sevoflurane, the two main anesthetic agents for maintenance of general anesthesia, in order to define a cut-off value for the prediction of a higher risk of postoperative delirium.

• Primary objective: comparison of EEG alpha power (dB) during maintenance of anesthesia with propofol and sevoflurane using data available in the NeuroSense® depth-of-anesthesia monitoring
• Secondary objectives: comparison of other EEG frequency bands during maintenance of anesthesia with propofol and sevoflurane using data from the NeuroSense® depth-of-anesthesia monitoring

Study Overview

• Status: Recruiting
• Conditions: Electroencephalography/Drug Effects
• Intervention / Treatment: Other: Maintenance of general anesthesia by Propofol; Other: Maintenance of general anesthesia by Sevoflurane

Detailed Description

Since the development and commercialization of quantitative EEG monitors, which compute an index to assess the depth of sedation, the interest of anesthesiologists for neurophysiology has increased considerably. Indeed, frontal EEG represents an accessible, non-invasive technique to monitor the brain, the target-organ of our hypnotic drugs.

Anesthesia interferes with the physiological oscillations generated by the brain, and these disturbances impact the EEG. For instance, common hypnotic agents used for the maintenance of general anesthesia, intravenous propofol or inhaled sevoflurane, provide a typical pattern on the raw EEG related to their main mechanism of action: predominant simultaneous frontal slow/delta (0.1-4 Hz) and alpha (8-12 Hz) oscillations.

Intraoperative alpha oscillations are currently being extensively studied, as they might be a potential biomarker of brain vulnerability, which could help in predicting postoperative delirium, one of the most prevalent neurological complication after surgery. Recently, in a prospective observational cohort study including 220 patients, we showed that adult patients undergoing elective cardiac surgery under sevoflurane anesthesia who had lower intraoperative frontal EEG alpha band power were at higher risk of postoperative delirium. Lower intraoperative frontal EEG alpha band power was also correlated with poorer preoperative cognitive scores in our clinical series, which confirms previously published observations.

However, some practical questions still need to be addressed before this electroencephalographical marker can be integrated into a risk-prediction model for postoperative delirium. More specifically, we are not currently able to suggest a "universal" cut-off value for intraoperative frontal alpha-band power under general anesthesia that could be useful for a daily clinical practice. For example, an important issue is that the definition of the cut-off value will highly depend on the choice of anesthetic drugs. Although propofol and volatile anesthetics, such as sevoflurane, share similar neurophysiological characteristics, their respective EEG patterns and spectrograms are not identical (increased power in the thêta-band with volatile anesthetics). Otherwise, both propofol and sevoflurane EEG patters become completely different when they are used in combination with other anesthetic agents, such as benzodiazepines, ketamine or dexmedetomodine. These combinations are frequently used in multimodal anesthesia practice, and can deeply impact EEG frequency band power values. Consequently, at the moment, "low" alpha band power remains rather an observation on our patients' EEG spectrogram throughout surgery than a quantifiable value.

The main objective of this study is a first step towards to definition of a cut-off value for EEG frontal alpha band power to predict postoperative delirium. We aim to determine whether there is a significant difference in EEG power spectrum ranges between propofol and sevoflurane, the two main anesthetic maintenance agents. More precisely, it would require "simple", non-balanced, maintenance of general anesthesia using either propofol or sevoflurane, with the avoidance of any other hypnotic drugs. This type of maintenance is frequently used for minor interventions requiring general anesthesia.

• Study Type: Interventional
• Enrollment (Estimated): 280
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Belgium
  • Brussels, Belgium, 1200
    • Recruiting
    • Cliniques Universitaires Saint-luc
    • Contact: Céline Khalifa, MD PhD; Phone Number: +3227641821; Email: celine.khalifa@saintluc.uclouvain.be
    • Contact: Laetitia Miltoni, MD; Phone Number: +3227641821
    • Sub-Investigator: Christine Watremez, MD PhD
    • Sub-Investigator: Mona Momeni, MD PhD
    • Sub-Investigator: David Kahn, MD
    • Principal Investigator: Céline Khalifa, MD PhD
    • Sub-Investigator: Robert Tircoveanu, MD
    • Sub-Investigator: Aurélie Jacobs Sariyar, MD
    • Sub-Investigator: Maximilien Cappe, MD
    • Sub-Investigator: Lina Puodzukaite, MD
    • Sub-Investigator: Guillaume Lemaire, MD

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria: Adult patients undergoing elective electrophysiological interventions, such as atrial fibrillation ablation procedures, under general anesthesia

• Capable to give informed consent
• French-speaking patients

Exclusion Criteria:

• Need for a premedication with benzodiazepine before anesthesia
• Reduced left ventricular ejection fraction (< 50%) or underlying cardiac pathology requiring a more balanced anesthesia (administration of benzodiazepine and/or ketamine during anesthesia)
• Preoperative MoCA score < 26/30 (for patients > ou = 55 years old)
• Patients treated with anti-epileptic drugs
• Patients treated with benzodiazepines (ex: for anxiolysis or sleep disorders)
• Emergencies
• Morbid obesity (BMI > 40kg/m2)
• Background of severe postoperative nausea/vomit

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Basic Science
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Propofol maintenance	Other: Maintenance of general anesthesia by Propofol; Maintenance of general anesthesia for simple electrophysiological procedures
Experimental: Sevoflurane maintenance	Other: Maintenance of general anesthesia by Sevoflurane; Maintenance of general anesthesia for simple electrophysiological procedures

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Alpha-band power	Power in decibels from the NeuroWave monitor under general anesthesia	Intra-operative

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Delta-band power	Power in decibels from the NeuroWave monitor	Intra-operative
Thêta-band power	Power in decibel from the NeuroWave monitor	Intra-operative
Bêta-band power	Power in decibel from the NeuroWave monitor	Intra-operative

Collaborators and Investigators

• Sponsor: Cliniques universitaires Saint-Luc- Université Catholique de Louvain

Study record dates

Study Major Dates

• Study Start (Actual): April 13, 2026
• Primary Completion (Estimated): December 1, 2027
• Study Completion (Estimated): December 1, 2027

Study Registration Dates

• First Submitted: April 17, 2026
• First Submitted That Met QC Criteria: April 24, 2026
• First Posted (Actual): May 1, 2026

Study Record Updates

• Last Update Posted (Actual): May 1, 2026
• Last Update Submitted That Met QC Criteria: April 24, 2026
• Last Verified: April 1, 2026

More Information

Terms related to this study

• Keywords: intraoperative electroencephalography; alpha-band power
• Other Study ID Numbers: 2025/15JUL/299

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