An interventional study of Carbon Dioxide in Hypoxia, Brain, Hyperoxia and Hypercapnia, sponsored by Washington University School of Medicine. Enrolling by invitation at 1 site in United States. Open to participants aged 18 Years and older, including healthy volunteers. Per ClinicalTrials.gov, last updated 2026-01-16.
Sponsored by Washington University School of Medicine · Not applicable, Interventional, and Other
The purpose of this research study is to better understand how blood flow and metabolism are different between normal controls and patients with disease.
The investigators will examine brain blood flow and metabolism using magnetic resonance imaging (MRI). The brain's blood vessels expand and constrict to regulate blood flow based on the brain's needs. The amount of expanding and contracting the blood vessels can do varies by age. The brain's blood flow changes in small ways during everyday activities, such as normal brain growth, exercise, or deep concentration. Significant illness or physiologic stress may increase the brain's metabolic demand or cause other bigger changes in blood flow. If blood vessels are not able to expand to give more blood flow when metabolic demand is high, the brain may not get all of the oxygen it needs. In less extreme circumstances, not having as much oxygen as it wants may cause the brain to grow and develop more slowly than it should.
One way to test the ability of the blood vessels to expand is by measuring blood flow while breathing in carbon dioxide (CO2). CO2 causes blood vessels in the brain to dilate without increasing brain metabolism. The study team will use a special mask to control the amount of oxygen and carbon dioxide patients breath in so that we can study how their brain reacts to these changes. This device designed to simulate carbon dioxide levels achieved by a breath-hold and target the concentration of carbon dioxide in the blood in breathing patients. The device captures exhaled gas and provides an admixture of fresh gas and neutral/expired gas to target different carbon dioxide levels while maintaining a fixed oxygen level. The study team will obtain MRI images of the brain while the subjects are breathing air controlled by the device.
81 studies on the registry are indexed under Hypoxia, Brain; 19 are open to participants now.
This study's planned enrollment of 48 is below the median of 60 across 55 interventional studies indexed under Hypoxia, Brain.
Browse Hypoxia, Brain studies →Washington University School of Medicine is the lead sponsor of 1,803 studies on the registry; 271 are open to participants now.
Of its 329 completed or terminated interventional studies of FDA-regulated products, 216 (66%) have results posted.
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Exclusion Criteria:
Subjects that cannot undergo an MRI scan due to one of the following indications:
Other: Carbon Dioxide
Other: Carbon Dioxide
The study team will administer inhaled carbon dioxide to the participants during an MRI at a level
Cerebral Oxygen Metabolism
Time frame: From the beginning of the MRI scan to the completion of the MRI scan -- 75 minutes.
Cerebrovascular Reactivity
Time frame: From administration of carbon dioxide to end of inhalation of carbon dioxide -- 15 minutes.
Eligibility is decided by the study team. Share this record with your doctor or contact the team directly.
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