A Phase 4 interventional study of Propofol (Group P) and Remimazolam group in General Anesthesia-Induced Altered Consciousness, sponsored by Beijing Chao Yang Hospital. Not yet recruiting at 1 site in China. Open to participants aged 6 Years to 80 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-09-23.
Sponsored by Beijing Chao Yang Hospital · Phase 4, Interventional, and Basic science
This study aims to investigate how general anesthetics alter brain activity and consciousness across different age groups. The study will evaluate four anesthetic agents with different mechanisms of action: propofol, remimazolam, esketamine, and dexmedetomidine. Electroencephalography (EEG) will be recorded during wakefulness, anesthetic induction, loss of responsiveness, and recovery of responsiveness to characterize changes in brain activity and brain network dynamics.
The study includes children aged 6-12 years undergoing surgery, healthy young adults aged 20-40 years, and healthy older adults aged 65-80 years. Resting-state EEG will be used to examine changes in brain rhythms, temporal and spatial brain dynamics, and network organization across different levels of consciousness. In a subgroup of young adult participants, auditory stimuli will also be presented continuously to investigate how the brain processes sounds and meaningful information as consciousness decreases and subsequently recovers.
The study will compare EEG changes across anesthetic agents, age groups, and states of consciousness. It will also evaluate the timing of loss and recovery of responsiveness, anesthetic dose-response relationships, and adverse events. The overall goal is to identify brain activity patterns associated with anesthesia-induced changes in consciousness and to provide a scientific basis for improved monitoring of consciousness and anesthetic depth.
Beijing Chao Yang Hospital is the lead sponsor of 140 studies on the registry; 49 are open to participants now.
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Exclusion Criteria:
Underlined terms in the criteria open these too. Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
The anaesthetists’ scale of health before surgery: I is healthy, II has a mild illness that is under control, III a severe one, IV a severe illness that is a constant threat to life. V and VI are used for the critically ill and for organ donors.
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
ASA physical status
The anaesthetists’ scale of health before surgery: I is healthy, II has a mild illness that is under control, III a severe one, IV a severe illness that is a constant threat to life. V and VI are used for the critically ill and for organ donors.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Informed consent
Before you join, the study team explains what taking part involves — its purpose, what happens, the risks and possible benefits — and answers your questions, so you can decide freely. Consent is usually recorded on a form (the informed consent form, ICF) signed by you or, where the law allows, by someone legally authorised to decide for you.
You can keep asking questions during the study, you are told of new information that matters, and you can choose to leave at any time.
Explained by clinicaltrials.gg, not part of the registry record. The study team decides who can take part.
Participants in this arm will receive propofol. In young and older healthy volunteers, propofol will be administered by target-controlled infusion, with the plasma target concentration increased by 0.5 μg/mL every 5 minutes up to a maximum of 5 μg/mL to induce loss of responsiveness. EEG will be recorded during wakefulness, anesthetic induction, loss of responsiveness, and recovery. Pediatric surgical participants in this group will undergo EEG recording during anesthesia in the operating room.
Drug: Propofol (Group P)
Participants in this arm will receive remimazolam. In young and older healthy volunteers, remimazolam will be administered intravenously at sequential infusion rates of 0.5, 1.0, 1.5, and 2.0 mg/kg/h, with each level maintained for 5 minutes, until loss of responsiveness is achieved. EEG will be recorded during wakefulness, anesthetic induction, loss of responsiveness, and recovery. Pediatric surgical participants in this group will undergo EEG recording during anesthesia in the operating room.
Drug: Remimazolam group
Participants in this arm will receive esketamine. In young and older healthy volunteers, esketamine will be administered intravenously with the infusion rate increased by 0.10 mg/kg/h every 5 minutes, up to a maximum of 0.50 mg/kg/h, to induce loss of responsiveness. EEG will be recorded during wakefulness, anesthetic induction, loss of responsiveness, and recovery. Pediatric surgical participants in this group will undergo EEG recording during anesthesia in the operating room.
Drug: Esketamine group
Participants in this arm will receive dexmedetomidine. In young and older healthy volunteers, dexmedetomidine will be administered intravenously with stepwise increases of 0.1 μg/kg/h, up to a maximum of 0.7 μg/kg/h, to induce loss of responsiveness. EEG will be recorded during wakefulness, anesthetic induction, loss of responsiveness, and recovery. Pediatric surgical participants in this group will undergo EEG recording during anesthesia in the operating room.
Drug: Dexmedetomidine group
Propofol will be administered by target-controlled infusion in young and older healthy volunteers. The plasma target concentration will be increased by 0.5 μg/mL every 5 minutes, up to a maximum of 5 μg/mL, until protocol-defined loss of responsiveness is achieved. Consciousness will be assessed every minute using the Modified Observer's Assessment of Alertness/Sedation (MOAA/S) scale, and EEG will be recorded throughout anesthetic induction and recovery.
Remimazolam will be administered intravenously in young and older healthy volunteers at sequential infusion rates of 0.5, 1.0, 1.5, and 2.0 mg/kg/h, with each level maintained for 5 minutes, until protocol-defined loss of responsiveness is achieved. Consciousness will be assessed every minute using the Modified Observer's Assessment of Alertness/Sedation (MOAA/S) scale, and EEG will be recorded throughout anesthetic induction and recovery.
Esketamine will be administered intravenously in young and older healthy volunteers. The infusion rate will be increased by 0.10 mg/kg/h every 5 minutes, up to a maximum of 0.50 mg/kg/h, until protocol-defined loss of responsiveness is achieved. Consciousness will be assessed every minute using the Modified Observer's Assessment of Alertness/Sedation (MOAA/S) scale, and EEG will be recorded throughout anesthetic induction and recovery.
Dexmedetomidine will be administered intravenously in young and older healthy volunteers with stepwise increases in the infusion rate of 0.1 μg/kg/h, up to a maximum of 0.7 μg/kg/h, until protocol-defined loss of responsiveness is achieved. Consciousness will be assessed every minute using the Modified Observer's Assessment of Alertness/Sedation (MOAA/S) scale, and EEG will be recorded throughout anesthetic induction and recovery.
Changes in Resting-State Quantitative EEG Measures Across Behavioral Responsiveness States
Continuous resting-state EEG will be quantified across awake baseline, anesthetic induction, loss of responsiveness, maintenance, emergence, and recovery. Prespecified measures include delta power (0.5-4 Hz), alpha power (8-12 Hz), theta/alpha power ratio, slow-wave index (SWI), burst suppression ratio (BSR), autocorrelation window at the first zero crossing (ACW-0), EEG complexity (gMLZC), and alpha-band (8-13 Hz) functional connectivity/network measures, including wPLI/dwPLI² and weighted global efficiency. Each measure will be analyzed separately.
Time frame: From the start of the 10-minute awake baseline through anesthetic induction, loss-of-responsiveness maintenance, emergence, and 30 minutes after recovery of responsiveness
Changes in Auditory-Evoked ERP and Time-Frequency EEG Measures Across Behavioral Responsiveness States
Auditory-evoked EEG will be quantified across awake baseline, anesthetic induction, loss of responsiveness, maintenance, emergence, and recovery. Event-related potential (ERP) measures include N100, mismatch negativity (MMN), N400, and P300 amplitudes and their state-related temporal dynamics. Stimuli include pure tones, white noise, characters, words, sentences, another person's name, and the participant's own name. Time-frequency measures include event-related theta-band activity (4-8 Hz), alpha-band activity (8-12 Hz), and intertrial phase coherence. Source-space analyses will localize N400 and P300 generators, and single-trial ERP amplitudes will be analyzed in relation to behavioral responsiveness. Each measure will be analyzed separately.
Time frame: From the start of the 10-minute awake baseline through anesthetic induction, loss of responsiveness, maintenance, emergence, and at least 10 minutes after recovery of responsiveness
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Studies of the drugs tested here: Propofol · Remimazolam · Esketamine · Dexmedetomidine