Neurochemical Mechanisms of the Awake vs. Anesthetized Brain

Mass General Brigham

Status and phase: Enrolling; Early Phase 1

Conditions: Healthy; Anesthesia

Treatments: Drug: Dexmedetomidine; Drug: Saline

Study type: Interventional

Funder types: Other

Identifiers

NCT05435560

2021P003426

Details and patient eligibility

About

The investigators will be studying the sedative drug dexmedetomidine using hybrid PET/fMRI/EEG imaging to better understand the neuropharmacology of anesthesia/artificially induced sleep.

Full description

A group of healthy volunteers will undergo simultaneous PET/fMRI/EEG imaging under two different conditions: while being administered a sedative (dexmedetomidine), and while being administered a normal saline infusion, as a control. The order of these two scans will be randomized, and the study design is open label (ie subjects and investigators know which session will be the control scan and which one will be the sedative scan). Investigators hope that by comparing the results of the sedative and control scans, the different neuromodulatory states involved in the transition from wakefulness to medically induced vs naturally occurring sleep can be better understood.

Enrollment: 30 estimated patients

Sex: All

Ages: 18 to 45 years old

Volunteers: Accepts Healthy Volunteers

Inclusion criteria

• Adults aged 18-45.
• No contraindications to MRI or PET scanning.

Exclusion criteria

• Contraindications to fMRI scanning and PET scanning (including presence of a cardiac pacemaker or pacemaker wires, metallic particles in the body, vascular clips in the head or previous neurosurgery, prosthetic heart valves, claustrophobia);
• Pregnancy or breast feeding;
• Current or past history of major medical, neurological, or psychiatric condition;
• History of major head trauma;
• Any cardiovascular disorders, including heart disorders or high blood pressure [>155/95];
• Breathing problems such as severe asthma;
• Bleeding disorder, or use of anticoagulants;
• Bladder obstruction, urinary problems, or history of impaired elimination;
• Known kidney or liver problems;
• Intestinal blockage;
• Raynaud syndrome
• Peripheral nerve injury;
• Diabetes;
• Glaucoma;
• Sleep disorder, such as sleep apnea, insomnia, or narcolepsy
• Current use of any drugs that affect sleep
• Current or recent use of medications (neurological or psychiatric) affecting brain function
• Current or past history of chronic pain (assessed at discretion of PI);
• History of allergic reactions
• History of chronic obstructive pulmonary diseases
• Ulcerative skin conditions or other dermatologic conditions which could interfere with blood pressure cuff placement
• Body mass index above 30
• Current smoker
• Lack of current health insurance coverage
• Employed under the direct supervision of the investigators conducting the research
• Hair in dreadlocks, twists, or braids that cannot be removed
• Eczema on the scalp or face

Trial design

Primary purpose: Basic Science

Allocation: Randomized

Interventional model: Crossover Assignment

Masking: None (Open label)

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30 participants in 2 patient groups, including a placebo group

Dexmedetomidine

Experimental group

Description:

During the imaging scan subjects will receive an initial 1µg/kg bolus of dexmedetomidine up to a maximum dose of 80 µg, infused through IV over 10 minutes. After the bolus has been administered, a constant infusion of up to 0.6 µg/kg/hr (0.01 µg/kg/min) of dexmedetomidine will be maintained for the remainder of the scan (about 60 minutes).

Treatment:

Drug: Dexmedetomidine

Saline

Placebo Comparator group

Description:

A saline infusion will be used as a placebo comparator for the dexmedetomidine infusion. It will be administered in the same manner and dosages as the dexmedetomidine.

Treatment:

Drug: Saline