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NCT Number: NCT07806903

Electroencephalographic Trajectories During Emergence From Inhalational and Total Intravenous Anesthesia

General anesthesia emergence is a critical transition during which patients recover from an anesthetic-induced unconscious state to consciousness. This period is associated with various early postoperative complications, including emergence agitation, postoperative nausea and vomiting, delayed recovery, and impaired recovery quality in the Post-Anesthesia Care Unit (PACU). Although total intravenous anesthesia (TIVA) and inhalational anesthesia (IA) are widely used maintenance strategies, differences in their effects on cerebral recovery patterns during emergence remain incompletely understood.

Conventional assessments of emergence, such as time to eye opening, extubation time, and clinical sedation assessments, mainly reflect behavioral recovery and cannot directly characterize the dynamic process of cerebral functional recovery. Electroencephalography (EEG) provides continuous and non-invasive measurement of cortical activity and may enable objective characterization of anesthetic emergence.

Previous studies suggest that emergence from anesthesia involves dynamic transitions among distinct EEG states rather than a simple reversal of anesthetic induction, and specific EEG trajectories may be associated with abnormal emergence and PACU delirium. Therefore, this single-center prospective observational cohort study aims to continuously collect emergence-phase EEG data from patients receiving TIVA or IA without altering clinical anesthesia management. The study will compare EEG trajectory characteristics, spectral features, and aperiodic parameters between different anesthesia maintenance modalities and explore their associations with emergence quality and early postoperative complications.

This study may provide further insights into neurophysiological patterns of anesthetic emergence and support future optimization of emergence monitoring and perioperative management.

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Key information

Conditions

Emergence From Anesthesia

Age range

18 year–60 year

Sex eligibility

All sexes

Study type

Observational

Primary location

Ruijin Hospital, Shanghai Jiao Tong University School of Medicine

Shanghai, China

Location contact

Qianzi Yang

CONTACT

[email protected]

+86 64370045

Who can participate

Healthy volunteers accepted: Yes

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

Inclusion criteria

  • Adults aged 18-60 years.
  • Patients classified as American Society of Anesthesiologists (ASA) physical status I-III.
  • Patients scheduled to undergo elective non-cardiac and non-neurosurgical surgery under general anesthesia.
  • Expected duration of surgery ≥60 minutes.
  • Expected intraoperative maintenance anesthesia with either total intravenous anesthesia (TIVA) or inhalational anesthesia .
  • Patients who understand the study procedures and voluntarily provide written informed consent.

Exclusion criteria

  • History of central nervous system disorders, including epilepsy, Parkinson's disease, dementia, previous stroke with residual neurological deficits, or other clinically significant neurological diseases.
  • Long-term use (≥4 weeks) of sedative-hypnotic drugs, antidepressants, antipsychotic medications, or other medications that may significantly affect central nervous system function.
  • Pre-existing cognitive impairment or severe visual/hearing impairment preventing assessment of recovery of consciousness.
  • Skin lesions, trauma, or other conditions affecting placement of frontal EEG electrodes.
  • Emergency surgery, neurosurgery, cardiac surgery, planned deep sedation with postoperative intubation, or direct transfer to the intensive care unit after surgery.
  • Severe intraoperative adverse events, including cardiac arrest, malignant hyperthermia, severe allergic reactions, major bleeding, or situations requiring substantial changes in the planned anesthesia maintenance strategy.
  • Body mass index (BMI) ≥30 kg/m² or ≤18 kg/m².
  • Refusal to participate or withdrawal of informed consent during the study.1. Adults aged 18-60 years, with no restriction on sex.

Treatment and study plan

No Intervention: Observational Cohort

Other

No Intervention: Observational Cohort

Primary outcomes

  1. EEG trajectories during emergence from anesthesia

    Time frame: From discontinuation of the anesthetic maintenance drugs until 30 minutes after tracheal extubation.

    Frontal EEG recordings will be analyzed to characterize spectral activity and its temporal evolution during emergence from general anesthesia. Prespecified EEG parameters will include delta-band spectral power and alpha/spindle-band spectral power derived from power spectral density estimates. These spectral features will be used to characterize EEG states and transitions during emergence, including state occupancy, transition timing, and transition sequences.

Secondary outcomes

  1. EEG spectral power characteristics

    Time frame: From discontinuation of the anesthetic maintenance drugs until 30 minutes after tracheal extubation

    Frontal EEG recordings will be obtained during emergence from general anesthesia. The EEG will be segmented into consecutive prespecified epochs, and spectral analysis will be performed for each segment. Power spectral density will be calculated within the following frequency bands: delta, 0.5-4 Hz; theta, 4-8 Hz; alpha/spindle, 8-13 Hz; beta, 13-30 Hz; and gamma, 30-45 Hz. Absolute power and relative power will be calculated for each frequency band. Relative power will be defined as the power within each frequency band divided by the total spectral power across the prespecified analysis frequency range. The alpha-to-delta power ratio, alpha peak frequency, and alpha peak power will also be calculated. Gamma-band findings will be considered exploratory because of possible electromyographic contamination.

  2. Aperiodic exponent of the EEG power spectrum

    Time frame: From discontinuation of the anesthetic maintenance drugs until 30 minutes after tracheal extubation

    The aperiodic exponent will be estimated from frontal EEG power spectra using a prespecified spectral parameterization method that separates periodic spectral peaks from the aperiodic 1/f-like background.

  3. Aperiodic offset of the EEG power spectrum

    Time frame: From discontinuation of the anesthetic maintenance drugs until 30 minutes after tracheal extubation

    The aperiodic offset will be estimated from frontal EEG power spectra using a prespecified spectral parameterization method that separates periodic spectral peaks from the aperiodic 1/f-like background.

  4. Auxiliary EEG and monitor-derived parameters during emergence

    Time frame: From discontinuation of the anesthetic maintenance drugs until 30 minutes after tracheal extubation

    Additional EEG-derived and monitor-generated parameters will be assessed during emergence from general anesthesia. Spectral edge frequency 90% (SEF90) will be calculated as the frequency below which 90% of the total EEG spectral power within the prespecified analysis frequency range is contained. In addition, the Ai Index and electromyographic (EMG) index generated by the EEG monitoring system will be recorded continuously during emergence.

  5. Length of stay in the postanesthesia care unit

    Time frame: From discontinuation of the anesthetic maintenance drugs until 30 minutes after tracheal extubation

    Duration from admission to discharge from the postanesthesia care unit.

  6. Aldrete score at PACU discharge

    Time frame: Before discharge from the postanesthesia care unit.

    Recovery status will be assessed using the Aldrete score at discharge from the postanesthesia care unit.

  7. Richmond Agitation-Sedation Scale score at PACU discharge

    Time frame: From discontinuation of the anesthetic maintenance drugs until 30 minutes after tracheal extubation

    Level of agitation and sedation will be assessed using the Richmond Agitation-Sedation Scale (RASS) at PACU discharge.

  8. Pain intensity measured using the Numeric Rating Scale at PACU discharge

    Time frame: From discontinuation of the anesthetic maintenance drugs until 30 minutes after tracheal extubation

    Pain intensity will be assessed using the 0-10 Numeric Rating Scale (NRS) at PACU discharge, with higher scores indicating greater pain intensity.

Study contacts

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

Qianzi Yang, MD, PhD

CONTACT

[email protected]

+86 64370045

Sponsors and collaborators

Lead sponsor

Ruijin Hospital

Other

Registry information

Important dates

Study start
2026
Primary completion
2027
Study completion
2027
First posted
Sep 8, 2026
Registry last updated
Sep 8, 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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