Incidence of Slow Delta EEG Frequencies (0.1-1 Hz) Before Burst Suppression

NCT07031427 | Not Yet Recruiting

• 1 other identifier: 2025-00301
• Study Type: observational
• Target: 30
• Locations: 1 country
• Sites: 2

Brief Summary

The electroencephalogram (EEG) measures brain waves during general anaesthesia via an electrode placed on the forehead. These brain waves show the different stages of natural sleep as well as the state of the brain when a patient is put under general anaesthesia for an operation. In this research project, the investigators aim to find out if the EEG signal shows slow wave activity (where an EEG wave repeats every 10 to 1 seconds) just before the onset of the burst suppression pattern, where the EEG waveform alternates between very small (suppression) and very large (burst) signals over a period of a few seconds. It is not currently known if and how often this occurs, but if it does, it would be a useful signal to help anaesthetists administer just the right dose of anaesthesia to patients.

Conditions

Burst Suppression; Anesthesia

Keywords

Electroencephalogram (EEG); General Anesthesia; Burst Suppression; Delta power; Slowwave power

Outcome Measures

Primary Outcomes (1)

• Slowwave Peak Amplitudes prior to Burst Suppression

  The primary variables of interest are peak amplitudes in the slow wave signal and absolute power in the EEG frequency spectra when recorded from immediately prior to the onset of burst suppression.

  This outcome is measured during the anesthesia for surgery, i.e., between when a patient is anaesthetised until they wake up following the operation, all on the same day.

Study Arms (1)

Patients over 60 requiring general anesthesia

The group in focus in this study are patients aged over 60 requiring general anesthesia for elective surgery

Eligibility Criteria

• Age: 60 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)
• Sampling Method: Non-Probability Sample

Study Population

Patients requiring elective surgery at either the Cantonal Hospital of Aarau, Switzerland, or at the Hirslanden Clinic Aarau, Switzerland.

You may qualify if:

• patients undergoing elective general anaesthesia, and
• aged 60 or above, and
• have a good comprehension of German, and
• require a general anaesthesia length of at least 1 hour (to ensure that we can record enough good quality EEG signal).

You may not qualify if:

• patients undergoing head or neck surgery or surgery in prone or lateral decubitus position (due to the limited placement space on the forehead required for the two EEG electrode systems, limited access to the forehead during surgery), or
• patients undergoing emergency surgery, operations only requiring local or regional anaesthesia with sedation, or
• patients who cannot follow procedures, or have an inability to give consent, or
• known participation in another human research project (ClinO/HRO) that may affect the objectives of this study.

Sponsors & Collaborators

• Insel Gruppe AG, University Hospital Bern: lead
• Kantonsspital Aarau: collaborator
• Hirslanden Clinic Aarau: collaborator

Study Sites (2)

Hirslanden Clinic Aarau

Aarau, Aagrau, 5001, Switzerland

Location

Cantonal Hospital of Aarau

Aarau, Canton of Aargau, 5001, Switzerland

Location

Related Publications (3)

• Ma K, Bebawy JF. Electroencephalographic Burst-Suppression, Perioperative Neuroprotection, Postoperative Cognitive Function, and Mortality: A Focused Narrative Review of the Literature. Anesth Analg. 2022 Jul 1;135(1):79-90. doi: 10.1213/ANE.0000000000005806. Epub 2021 Dec 6.

  PMID: 34871183 BACKGROUND

• Gutierrez R, Purdon PL. Phase-amplitude coupling during maintenance of general anaesthesia: towards a better understanding of anaesthetic-induced brain dynamics in children. Br J Anaesth. 2023 Sep;131(3):439-442. doi: 10.1016/j.bja.2023.06.030. Epub 2023 Aug 4.

  PMID: 37611972 BACKGROUND

• Chen J, Li W, Chen Q, Zhou Z, Chen C, Hu Y, Si Y, Zou J. Optimizing anesthesia management based on early identification of electroencephalogram burst suppression risk in non-cardiac surgery patients: a visualized dynamic nomogram. Ann Med. 2024 Dec;56(1):2407067. doi: 10.1080/07853890.2024.2407067. Epub 2024 Sep 24.

  PMID: 39317392 BACKGROUND

Central Study Contacts

Darren Hight, PhD.

CONTACT

+41 78 719 03 01; darren.hight@insel.ch

Study Design

• Study Type: observational
• Observational Model: COHORT
• Time Perspective: PROSPECTIVE
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: June 12, 2025
• First Posted: June 22, 2025
• Study Start: July 1, 2025
• Primary Completion: December 1, 2025
• Study Completion: December 1, 2025
• Last Updated: June 27, 2025

Record last verified: 2025-06

Data Sharing

• IPD Sharing: Will not share

Locations

CH (2)