NCT02493985

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.

Trial Health

100
On Track

Trial Health Score

Automated assessment based on enrollment pace, timeline, and geographic reach

Enrollment
6

participants targeted

Target at below P25 for phase_1 healthy

Timeline
Completed

Started Jun 2015

Shorter than P25 for phase_1 healthy

Status
completed

Health score is calculated from publicly available data and should be used for screening purposes only.

Trial Relationships

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Study Timeline

Key milestones and dates

Study Start

First participant enrolled

June 1, 2015

Completed
26 days until next milestone

First Submitted

Initial submission to the registry

June 27, 2015

Completed
4 days until next milestone

Primary Completion

Last participant's last visit for primary outcome

July 1, 2015

Completed
Same day until next milestone

Study Completion

Last participant's last visit for all outcomes

July 1, 2015

Completed
9 days until next milestone

First Posted

Study publicly available on registry

July 10, 2015

Completed
Last Updated

January 13, 2016

Status Verified

January 1, 2016

Enrollment Period

1 month

First QC Date

June 27, 2015

Last Update Submit

January 12, 2016

Conditions

Healthy

Keywords

Brain physiologyIntracranial pressureCognitionCerebrovascularHead down tiltSpace flight

Outcome Measures

Primary Outcomes (5)

  • Changes in cerebral blood flow: Transcranial doppler

    Transcranial Doppler derived measurements of mean cerebral blood flow velocity

    24 and 48 hours from baseline measurements

  • Changes in intracranial volume

    Cerebrotech monitor derived intracranial fluid volume changes (percentage change)

    24 and 48 hours from baseline measurements

  • Changes in intracranial pressure

    Vittamed ICP meter derived intracranial pressure (mmHg)

    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

    24 and 48 hours from baseline measurements

  • Changes in cerebral blood flow: cFLOW

    cFLOW derived changes in cerebral blood flow index

    24 and 48 hours from baseline measurements

Secondary Outcomes (8)

  • Tolerability of combined -12 head down tilt and 0.5% carbon dioxide

    Within 48 hours from baseline

  • Changes in intraocular pressure

    24 and 48 hours from baseline measurements

  • Changes in pulmonary mechanics

    24 and 48 hours from baseline measurements

  • Changes in internal jugular vein volumes

    48 hours from baseline measurements

  • Changes in peripheral arterial vasoreactivity

    48 hours from baseline measurements

  • +3 more secondary outcomes

Study Arms (2)

Atmosphere 1 - Ambient air

ACTIVE COMPARATOR

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

Atmosphere 2 - 0.5% CO2

EXPERIMENTAL

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

Interventions

0.5% CO2OTHER

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

Atmosphere 2 - 0.5% CO2
ambient airOTHER

The subjects will be randomized to breath ambient air during one of the -12 degree head down tilt body position periods in crossover design

Atmosphere 1 - Ambient air

Eligibility Criteria

Age30 Years - 55 Years
Sexmale
Healthy VolunteersYes
Age GroupsAdult (18-64)

You may qualify if:

  • 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

You may not qualify if:

  • 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
  • +42 more criteria

Contact the study team to confirm eligibility.

Sponsors & Collaborators

MeSH Terms

Interventions

Particulate Matter

Intervention Hierarchy (Ancestors)

Complex Mixtures

Study Design

Study Type
interventional
Phase
phase 1
Allocation
RANDOMIZED
Masking
QUADRUPLE
Who Masked
PARTICIPANT, CARE PROVIDER, INVESTIGATOR, OUTCOMES ASSESSOR
Purpose
DIAGNOSTIC
Intervention Model
CROSSOVER
Sponsor Type
OTHER
Responsible Party
PRINCIPAL INVESTIGATOR
PI Title
Assistant Professor of Neurology and Space Medicine

Study Record Dates

First Submitted

June 27, 2015

First Posted

July 10, 2015

Study Start

June 1, 2015

Primary Completion

July 1, 2015

Study Completion

July 1, 2015

Last Updated

January 13, 2016

Record last verified: 2016-01