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Assessing Covert Consciousness During Dexmedetomidine and Ketamine Sedation: An fMRI Study

NCT07705022 · Status: ENROLLING_BY_INVITATION · Phase: PHASE2 · Type: INTERVENTIONAL · Enrollment: 60

Last updated 2026-08-11

No results posted yet for this study

Summary

This research is studying whether mental functions take place during different levels of anesthesia, using a commonly used drug (either dexmedetomidine \[with propofol in some participants\] or ketamine), which shows areas in the brain involved in thinking at different depths of anesthesia. As a result of this study, the researchers expect to gain a deeper understanding of mental function during different levels of anesthesia.

Conditions

  • Healthy
  • Covert Consciousness

Interventions

DRUG

Dexmedetomidine (+propofol as indicated)

Dexmedetomidine dosing will follow FDA-labeled parameters for procedural sedation, with a loading dose of 1 mcg/kg administered intravenously over 10 minutes, followed by maintenance infusion within the range of 0.2 to 1.0 mcg/kg/hr, titrated to clinical effect under anesthesiologist supervision. Sedation depth will be assessed behaviorally using standardized squeeze-response testing to determine lost responsiveness (LOR). If LOR is not achieved within labeled dexmedetomidine dosing limits, low-dose propofol will be conditionally added using a target-controlled infusion at an effect-site concentration of 0.5-1.5 μg/ml, which is below typical induction levels and intended to provide supplemental sedation while preserving spontaneous ventilation. Once LOR is achieved, sedation will be maintained within the approved dexmedetomidine range, with adjunct propofol continued only as clinically indicated.

DRUG

Ketamine

participants will first receive a subanesthetic ketamine infusion of 0.5 mg/kg administered intravenously over 40 minutes. After that, 1.5 mg/kg ketamine will be administered slowly as a bolus over 60 seconds. Based on prior experience with this paradigm, most subjects who lose responsiveness do so for approximately 10 minutes following the bolus dose. For a 70 kg healthy subject, the total ketamine dose in this paradigm is approximately 140 mg. This dosing remains within the range of standard anesthetic induction dosing, which is typically 1.5 to 2 mg/kg in clinical practice.

Sponsors & Collaborators

Principal Investigators

  • Zirui Huang, PhD · University of Michigan

Study Design

Allocation
RANDOMIZED
Purpose
BASIC_SCIENCE
Masking
SINGLE
Model
PARALLEL

Eligibility

Min Age
18 Years
Max Age
40 Years
Sex
ALL
Healthy Volunteers
Yes

Timeline & Regulatory

Start
2026-08-07
Primary Completion
2028-01-31
Completion
2028-01-31
FDA Drug
Yes

Countries

  • United States

Study Locations

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Drugs
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Read the full study record

This page highlights key information. For complete eligibility criteria, study locations, investigator contacts, and the full protocol, visit the original record on ClinicalTrials.gov.

View NCT07705022 on ClinicalTrials.gov