Linking whole‑brain EEG patterns to changes in consciousness during anesthesia

EEG Signatures of Unconsciousness Induced by Anesthetic Agents and Their Dynamics Across the Consciousness Continuum

This study will try to find EEG patterns that reliably show when adults lose consciousness during induction of general anesthesia for elective surgery.

Quick facts

• Study type: Observational
• Enrollment: 250 (estimated)
• Ages: 18 Years to 80 Years
• Sex: All
• Sponsor: Huazhong University of Science and Technology (other)
• Locations: 1 site (Wuhan, Hubei)
• Trial ID: NCT07410702 on ClinicalTrials.gov

What this trial studies

This is a prospective, single‑center observational cohort of about 250 adults (≥18 years, ASA I–III, MMSE ≥24, BMI ≤30) undergoing elective surgery at Tongji Hospital who will receive one of five intravenous induction agents chosen by their clinicians. High‑density 32‑channel EEG, BIS values, and behavioral state assessments using the MOAA/S scale will be recorded continuously during induction, with preoperative cognitive testing performed before anesthesia. Researchers blinded to group allocation will extract dynamic EEG features and develop models to identify drug‑agnostic biomarkers of anesthetic depth and a universal assessment algorithm that addresses known BIS limitations. No experimental drugs or departures from standard clinical care are involved.

Who should consider this trial

Good fit: Adults (age ≥18) scheduled for elective surgery under general anesthesia with ASA physical status I–III, BMI ≤30, normal cognition (MMSE ≥24), and ability to provide informed consent are ideal candidates.

Not a fit: People with major neurological or psychiatric disorders, a history of substance abuse, pregnant patients, those unable to consent, emergency or pediatric cases, or patients with BMI >30 are unlikely to be eligible or to benefit from the results.

Why it matters

Potential benefit: If successful, this work could enable a more reliable, drug‑independent monitor of anesthetic depth that reduces the risks of intraoperative awareness or excessive anesthesia.

How similar studies have performed: Previous EEG research has identified drug‑specific signatures of anesthetic depth and shown promise for alternative monitors, but a validated universal, drug‑agnostic EEG biomarker has not yet been proven.

Eligibility criteria

Inclusion Criteria:

1. Age ≥ 18 years.
2. Scheduled to undergo elective surgery requiring general anesthesia with endotracheal intubation or laryngeal mask airway (LMA).
3. American Society of Anesthesiologists (ASA) Physical Status Class I to III.
4. Preoperative Mini-Mental State Examination (MMSE) score ≥ 24, indicating normal cognitive function.
5. Body mass index (BMI) ≤ 30 kg/m².
6. Ability to understand the study and provide written informed consent.

Exclusion Criteria:

1. History of drug abuse or dependence.
2. Known major neurological disorders (e.g., epilepsy, stroke, neurodegenerative diseases).
3. History of major psychiatric disorders.
4. Known or suspected pregnancy.
5. Inability to provide informed consent due to cognitive impairment, language barrier, or any other reason.

Where this trial is running

Wuhan, Hubei

• Department of Anaesthesiology, Tongji Hospital of Tongji Medical College, Huazhong University of Science and Technology — Wuhan, Hubei, China (RECRUITING)

Study contacts

• Principal investigator: Pu Zhou, PhD. — Huazhong University of Science and Technology
• Study coordinator: Hua Zheng, MD. & PhD.

Conditions: Altered State of Consciousness, General Anesthetics, Electroencephalography, Neural correlates of consciousness, Consciousness monitoring