A Phase 1 interventional study of 0.5% CO2 and ambient air in Healthy, sponsored by Baylor College of Medicine. Completed. Open to male participants aged 30 Years to 55 Years, including healthy volunteers. Per ClinicalTrials.gov, last updated 2016-01-13.
Sponsored by Baylor College of Medicine · Phase 1, Interventional, and Diagnostic
The purpose of this study is to study the effects of carbon dioxide combined with head down tilt on cerebral physiology and anatomy. This paradigm will help establish a ground-based analog for spaceflight, and also evaluate the ability of non-invasive devices to monitor brain physiology.
Many of the long duration astronauts develop visual changes, associated with neuroophthalmological abnormalities suggesting elevated intracranial pressure. There is currently no suitable ground based analog to simulate these changes on Earth, or a standard methodological approach to monitoring the combined effects of head down tilt and atmospheric carbon dioxide. Given that carbon dioxide and cephalad fluid shifting are known factors in spaceflight, we sought to evaluate an approach to monitoring these effects in healthy subject in a ground based analog on Earth.
Baylor College of Medicine is the lead sponsor of 747 studies on the registry; 111 are open to participants now.
Of its 84 completed or terminated interventional studies of FDA-regulated products, 45 (54%) have results posted.
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Exclusion Criteria:
First, the subjects will have 1 baseline day in the upright body position. This will be followed by 28 hours of head down tilt body position and ambient air at sea level, followed by 2 hour exposure of 3% carbon dioxide inhalation.
Other: ambient air
First, the subjects will have 1 baseline day in the upright body position. This will be followed by 28 hours of head down tilt body position and air with 0.5% carbon dioxide, followed by 2 hour exposure of 3% carbon dioxide inhalation.
Other: 0.5% CO2
The subjects will be randomized to breath 0.5% carbon dioxide during one of the -12 degree head down tilt body position periods in crossover design
The subjects will be randomized to breath ambient air during one of the -12 degree head down tilt body position periods in crossover design
Changes in cerebral blood flow: Transcranial doppler
Transcranial Doppler derived measurements of mean cerebral blood flow velocity
Time frame: 24 and 48 hours from baseline measurements
Changes in intracranial volume
Cerebrotech monitor derived intracranial fluid volume changes (percentage change)
Time frame: 24 and 48 hours from baseline measurements
Changes in intracranial pressure
Vittamed ICP meter derived intracranial pressure (mmHg)
Time frame: 24 and 48 hours from baseline measurements
Changes in cognitive function
Cognition battery score (max 1000): tests multiple cognitive domains including spatial memory, psychomotor processing speed, facial emotional recognition
Time frame: 24 and 48 hours from baseline measurements
Changes in cerebral blood flow: cFLOW
cFLOW derived changes in cerebral blood flow index
Time frame: 24 and 48 hours from baseline measurements
Tolerability of combined -12 head down tilt and 0.5% carbon dioxide
Assess safety outcomes: tolerance of condition through duration of study and number of adverse events
Time frame: Within 48 hours from baseline
Changes in intraocular pressure
iCare derived intraocular pressure measurements from both eyes (mmHg)
Time frame: 24 and 48 hours from baseline measurements
Changes in pulmonary mechanics
minute ventilation, respiratory rate and vital capacity
Time frame: 24 and 48 hours from baseline measurements
Changes in internal jugular vein volumes
Ultrasound derived measure of right internal jugular vein cross sectional areas
Time frame: 48 hours from baseline measurements
Changes in peripheral arterial vasoreactivity
Ultrasound Doppler Measurement of arterial diameter and flow (cm/sec) after transient cuff occlusion of brachial artery
Time frame: 48 hours from baseline measurements
Changes in cardiac hemodynamics
Assessment of cardiac output, stroke volume, heart rate, blood pressure
Time frame: 48 hours from baseline measurements
Changes in olfactory threshold
Sniffin' sticks threshold testing for phenyethyl alcohol
Time frame: 24 and 48 hours from baseline measurement
Changes in pulmonary gas exchange
changes in arterial pH and partial pressure CO2
Time frame: 24 and 48 hours from baseline measurements
No study locations are listed for this record.
The record gives a start of Jun 2015, a primary completion of Jul 2015 and a completion of Jul 2015. It does not say whether these dates are actual or estimated.
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This study is completed, as verified in Jan 2016. You cannot join it, but the record below documents what was studied.
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