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Trial record 45 of 1686 for:    CARBON DIOXIDE AND dioxide

Studying Physiological and Anatomical Cerebral Effects of Carbon Dioxide and Tilt (SPACE-COT)

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ClinicalTrials.gov Identifier: NCT02493985
Recruitment Status : Completed
First Posted : July 10, 2015
Last Update Posted : January 13, 2016
Sponsor:
Collaborators:
National Space Biomedical Research Institute
DLR German Aerospace Center
The University of Texas Health Science Center, Houston
University of Pennsylvania
Harvard University
University of Cologne
Information provided by (Responsible Party):
Eric Michael Bershad, Baylor College of Medicine

Brief Summary:
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.

Condition or disease Intervention/treatment Phase
Healthy Other: 0.5% CO2 Other: ambient air Phase 1

Detailed Description:
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.

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Study Type : Interventional  (Clinical Trial)
Actual Enrollment : 6 participants
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Primary Purpose: Diagnostic
Official Title: Studying Physiological and Anatomical Cerebral Effects of Carbon Dioxide and Tilt
Study Start Date : June 2015
Actual Primary Completion Date : July 2015
Actual Study Completion Date : July 2015

Resource links provided by the National Library of Medicine


Arm Intervention/treatment
Active Comparator: Atmosphere 1 - 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 ambient air at sea level, followed by 2 hour exposure of 3% carbon dioxide inhalation.
Other: ambient air
The subjects will be randomized to breath ambient air during one of the -12 degree head down tilt body position periods in crossover design

Experimental: Atmosphere 2 - 0.5% CO2
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




Primary Outcome Measures :
  1. Changes in cerebral blood flow: Transcranial doppler [ Time Frame: 24 and 48 hours from baseline measurements ]
    Transcranial Doppler derived measurements of mean cerebral blood flow velocity

  2. Changes in intracranial volume [ Time Frame: 24 and 48 hours from baseline measurements ]
    Cerebrotech monitor derived intracranial fluid volume changes (percentage change)

  3. Changes in intracranial pressure [ Time Frame: 24 and 48 hours from baseline measurements ]
    Vittamed ICP meter derived intracranial pressure (mmHg)

  4. Changes in cognitive function [ Time Frame: 24 and 48 hours from baseline measurements ]
    Cognition battery score (max 1000): tests multiple cognitive domains including spatial memory, psychomotor processing speed, facial emotional recognition

  5. Changes in cerebral blood flow: cFLOW [ Time Frame: 24 and 48 hours from baseline measurements ]
    cFLOW derived changes in cerebral blood flow index


Secondary Outcome Measures :
  1. Tolerability of combined -12 head down tilt and 0.5% carbon dioxide [ Time Frame: Within 48 hours from baseline ]
    Assess safety outcomes: tolerance of condition through duration of study and number of adverse events

  2. Changes in intraocular pressure [ Time Frame: 24 and 48 hours from baseline measurements ]
    iCare derived intraocular pressure measurements from both eyes (mmHg)

  3. Changes in pulmonary mechanics [ Time Frame: 24 and 48 hours from baseline measurements ]
    minute ventilation, respiratory rate and vital capacity

  4. Changes in internal jugular vein volumes [ Time Frame: 48 hours from baseline measurements ]
    Ultrasound derived measure of right internal jugular vein cross sectional areas

  5. Changes in peripheral arterial vasoreactivity [ Time Frame: 48 hours from baseline measurements ]
    Ultrasound Doppler Measurement of arterial diameter and flow (cm/sec) after transient cuff occlusion of brachial artery

  6. Changes in cardiac hemodynamics [ Time Frame: 48 hours from baseline measurements ]
    Assessment of cardiac output, stroke volume, heart rate, blood pressure

  7. Changes in olfactory threshold [ Time Frame: 24 and 48 hours from baseline measurement ]
    Sniffin' sticks threshold testing for phenyethyl alcohol

  8. Changes in pulmonary gas exchange [ Time Frame: 24 and 48 hours from baseline measurements ]
    changes in arterial pH and partial pressure CO2



Information from the National Library of Medicine

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Ages Eligible for Study:   30 Years to 55 Years   (Adult)
Sexes Eligible for Study:   Male
Accepts Healthy Volunteers:   Yes
Criteria

Inclusion Criteria:

  • Male
  • Ages between 30 to 55 years old
  • Body Mass Index (BMI) of 20-26 kg/m2
  • Weight between 65-85 kg
  • Height between 158-190 cm
  • Non-smoker, for at least six months before the start of the study
  • VO2 max of at least 30ml/kg/min

Exclusion Criteria:

  • History of intracranial pressure elevation
  • History of abnormal intraocular pressure
  • Ophthalmological conditions: glaucoma, retinopathy, severe cataracts, eye trauma or implants.
  • History of diseases of the optic nerve
  • Pre-existing corneal injury
  • History of these eye surgeries: implanted lens, corneal transplant, recent (less than 6 months) LASIK surgery
  • Congenital abnormalities of the anterior chamber
  • Active eye infections, recent corneal abrasions, inflammation
  • Intraocular pressure greater than 20 mm Hg
  • Viral or bacterial eye infection Severe dry eye syndrome
  • Retinal or choroidal detachment
  • More than -6,0 dpr (high myopia)
  • More than +5,0 dpr
  • Arm or shoulder injury in the past year
  • Psychiatric conditions including major depression, bipolar disorder or severe anxiety
  • History of cerebrovascular disease including brain aneurysms, stroke, transient ischemic attack, brain hemorrhage, arteriovenous malformations History of brain tumor, congenital cysts, hydrocephalus, brain injury (requiring hospitalization)
  • Meningitis/encephalitis
  • Epilepsy
  • History of severe hypertension (> 160/90 mmHg),
  • Diabetes mellitus
  • Coronary artery disease
  • Congestive heart failure
  • Ventricular or atrial arrhythmias
  • Autonomic disorders (syncope, autoimmune neuropathy)
  • Hepatic disease
  • Renal disease
  • Chronic infections including HIV, Hepatitis B or C, Lyme disease
  • History of hematological disease including hemophilia, leukemia, thrombocytosis, thrombocytopenia, myelodysplastic syndrome, autoimmune disease (lupus, rheumatoid arthritis, Sjogren's syndrome)
  • History of malignancy except for basal cell carcinoma
  • Chronic back pain (inability to lay in bed for long periods of time)
  • Conditions that would preclude MRI including severe claustrophobia, pace maker or other metallic implants or devices
  • Sleep disturbances including: obstructive sleep apnea, narcolepsy, insomnia - Medications that exert cardiovascular, cerebrovascular or psychiatric function (i.e. beta blockers, calcium channel blockers, diuretics, diamox, sedatives) Drug, medication or alcohol abuse (regular consumption of more than 20-30 g alcohol/day)*
  • Smoking
  • VO2 max less than 30 ml/kg/min or greater than 60 ml/kg/min
  • Vegetarian, vegan
  • Migraine
  • Previous psychiatric illness
  • Hiatus hernia
  • Gastro-esophageal reflux
  • Diabetes mellitus
  • Rheumatic illness
  • Muscle or joint disorder
  • Pronounced orthostatic intolerance (< 10 min standing)
  • Hyperlipidaemia
  • Thyroid gland disorder: deviations from normal values for TSH in plasma
  • Hyper-homocysteinaemia
  • Hyperuricaemia or hypouricaemia: deviations from normal values for uric acid in plasma.
  • Hypercalcaemia or hypocalcaemia: deviations from normal values for calcium in plasma.
  • Iron deficiency
  • Vitamin D deficiency
  • Baseline blood gas values deviating from the normal reference values
  • Elevated risk of venous thromboembolism including deep venous thrombosis, pulmonary embolism
  • Chronic back complaints
  • Participation in another clinical study within the last 3 months before start of this study
  • Criminal record
  • Stomach sleepers
  • Any other medical condition that the investigators consider a contraindication to the study procedures that would make it unsafe or confound the measurements.

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Responsible Party: Eric Michael Bershad, Assistant Professor of Neurology and Space Medicine, Baylor College of Medicine
ClinicalTrials.gov Identifier: NCT02493985     History of Changes
Other Study ID Numbers: H-36485
First Posted: July 10, 2015    Key Record Dates
Last Update Posted: January 13, 2016
Last Verified: January 2016
Keywords provided by Eric Michael Bershad, Baylor College of Medicine:
Brain physiology
Intracranial pressure
Cognition
Cerebrovascular
Head down tilt
Space flight