HealthyPhase 2NCT07705022
Assessing Covert Consciousness During Dexmedetomidine and Ketamine Sedation: An fMRI Study
A Phase 2 study testing Dexmedetomidine (+propofol as indicated) and Ketamine in people with Healthy and Covert Consciousness, run by University of Michigan at 1 site in United States.
Trial 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. Read more about this study
- Who is it for?
- Ages 18 to 40 yearsHealthy volunteers can take part
- Conditions the study is for
- Healthy, Covert Consciousness
- What is being tested?
- Dexmedetomidine (+propofol as indicated) and Ketamine
- Type of treatment
- Injection or infusion
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 60 participants
- Where
- 1 siteUnited States
- Study dates
- 7 Aug 2026to Jan 2028
- Phase
- Phase 2
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 40 years
- All sexes
- Healthy volunteers accepted
- Adult
Who may be able to join
- Healthy study subjects with American Society of Anesthesiologists (ASA)-1 status
- Right-handed
- Body mass index (BMI) less than 30
- Participants will have the experience of playing tennis (or other racquet sport) at least 30 times in their lifetime
- English speaking
Who cannot join
- Medical contraindication to MRI scanning; are unable to undergo MRI scanning because of possible pregnancy or currently breastfeeding
- BMI greater than or equal to 30
- Metallic substances in the body
- claustrophobia, anxiety, or cardiopulmonary disease; or have an intracranial structural abnormality on T1-weighted MRI scans
- history of allergy to dexmedetomidine, ketamine, propofol, or any components of these medications, eggs or egg products, soybean or soybean products
- neurological, cardiovascular, or pulmonary illness
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- significant head injury with loss of consciousness; learning disability or other developmental disorder
- sleep apnea or any severe snoring history
- gastroesophageal reflux disease (GERD) or heartburn; pancreatitis or a history of pancreatitis,
- sensory/motor loss sufficient to interfere with performance of the study
- epilepsy/seizure disorder (including a history of seizures) or stroke (including a history of stroke).
- history of schizophrenia spectrum disorder, bipolar disorder, other psychotic disorder, or any prior adverse psychiatric reaction to ketamine or similar drugs
- Participants taking medications that, in the judgment of the investigators or attending anesthesiologist, may interact with the study drugs or increase the risk of participation will also be excluded
- participants with hypertension or diabetes mellitus
- tattoos in the head or neck region will be excluded from study; other tattoos are subject to determination by investigators based on their assessment regarding participant safety
- recent food or liquid intake (within 8 hours)
- history of drug use, have a positive drug screen, are unwilling to abstain from alcohol for 24 hours prior to dosing, or have a current history of nicotine use.
- Potential participants who have participated in a clinical trial using an investigational drug or device within 30 days will be considered for enrollment after 30 days.
- History of a difficult airway with a previous anesthetic
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
About this study
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.
Read the detailed description
Dexmedetomidine is an FDA-approved sedative agent and is used off-label in this study for controlled experimental modulation of consciousness under direct anesthesiology supervision. Ketamine is a FDA-approved anesthetic and analgesic agent and is used off-label in this study for controlled experimental modulation of consciousness under direct anesthesiology supervision.
Using fMRI and established cognitive paradigms, the proposed study will directly examine residual conscious processing under dexmedetomidine and ketamine and compare these findings with our existing propofol dataset from NCT03361605.
- Conditions
- Healthy, Covert Consciousness
- Being tested
- Dexmedetomidine (+propofol as indicated), Ketamine
- Keywords
- Anesthesia, Functional magnetic resonance imaging (fMRI)
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
Dexmedetomidine (+propofol as indicated)Drug
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.
KetamineDrug
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.
| Study group | Role | What they receive |
|---|---|---|
| Dexmedetomidine during fMRI | Experimental | About 30 healthy participants will be randomized to this arm. Receives: Drug: Dexmedetomidine (+propofol as indicated) |
| Ketamine during fMRI | Experimental | About 30 healthy participants will be randomized to this arm. Receives: Drug: Ketamine |
What is being measured
The primary outcome is the main question the study is designed to answer.
Blood Oxygen Level Dependent (BOLD) response to mental imagery tasks
Three mental imagery tasks will be used: tennis imagery, navigation imagery, and hand-squeeze imagery
Measured: Up to approximately 130 minutes
Secondary outcomes (1)
Grip force (in mmHg) of participants' hand squeezing on a rubber ball in response to squeeze instructions
Measured: Up to approximately 130 minutes
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted15 Jul 2026
- Study start7 Aug 2026
- Primary completionJan 2028 (estimated)
- Study completionJan 2028 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for HealthyStudies of the same condition, open and under way.
- More trials run by University of MichiganThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 2
- Primary purpose
- Basic science
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Single blind
- Who is masked
- Participant
- Enrolment
- 60 participants (estimated)
Sponsor and investigators
- Lead sponsor
- University of Michigan
- Sponsor type
- University, hospital or other
- Collaborators
- National Institute of General Medical Sciences (NIGMS)
- Responsible party
- Principal investigator, Zirui Huang, University of Michigan
- Investigators
- Zirui Huang, PhD, Principal investigator, University of Michigan
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07705022
- Sponsor's protocol ID
- HUM00285398
- Other IDs
- R01GM103894
- Status last verified
- Aug 2026
- First submitted
- 10 Jul 2026
- Last updated
- 11 Aug 2026
- Results posted
- No
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- Yes: Data collected in the proposed experiments will be shared at the OpenNeuro. Preprocessed, curated, artifact-free data will be preserved and shared. Detailed documentation for reproducing the specific analyses will be provided in publications and in open sharing. In addition to the fMRI imaging data, task related paradigm designs and experiment definitions will be shared in OpenNeuro.