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Fluid Shifts Before, During and After Prolonged Space Flight and Their Association with Intracranial Pressure and Visual Impairment (Fluid_Shifts)
Research Area:
Biomedical countermeasures
Ocular physiological phenomena
Species Studied
Scientific Name: Homo sapiens Species: Human

The purpose of the proposed work is to objectively characterize the changes in fluid distribution, including intra/extracellular and intra/extravascular fluid shifts, by applying advanced non-invasive assessment technologies before, during, and after long-duration space flight. Additionally, investigators will examine the relationship between the type and magnitude of the fluid shift with any effects on eye morphology and vision disturbances, intraocular pressure (IOP), and measures of intracranial pressure. Further, they seek to determine whether the magnitude of fluid shifts during space flight, as well as the above effects of those shifts can be predicted based upon crewmember baseline data and responses to acute head-down tilt (HDT) tests performed before launch. Finally, they propose to evaluate the effect of lower body negative pressure (LBNP) on the above parameters.

Specific Aims:

  1. To characterize fluid distribution and compartmentalization before, during, and after long-duration space flight.
  2. To correlate in-flight alterations of eye structure, ocular vascular parameters, and vision with headward fluid shifts, vascular dimensions, and flow patterns.
  3. To determine systemic and ocular factors of individual susceptibility to the development of Intracranial Pressure (ICP) elevation and/or vision alterations.

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Macias BR1, Liu JH, Grande-Gutierrez N, and Hargens AR. Intraocular and intracranial pressures during head-down tilt with lower body negative pressure. Aviation, Space, and Environmental Medicine. 2015. January; 86(1):3-7. []

Intracranial pressure
Optic nerve
Carotid arteries
Retinal artery

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Data Information
Data Availability
Archiving in Progress. Some restricted access data exist for this experiment.
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CCFP Acoustic Reflex Threshold
CCFP Evoked Waveform
CCFP Passive Waveform
CCFP Pulse Ox Waveform
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Mission/Study Information
Mission Launch/Start Date Landing/End Date Duration
Expedition 42 11/10/2014 03/11/2015 121 days
Expedition 43 03/11/2015 06/10/2015 91 days
Expedition 44 06/10/2015 09/11/2015 93 days
Expedition 45 09/11/2015 12/11/2015 91 days
Expedition 46 12/11/2015 03/02/2016 82 days
Expedition 47 03/02/2016 06/18/2016 108 days
Expedition 48 06/18/2016 09/06/2016 80 days
Expedition 49 09/06/2016 10/30/2016 54 days
Expedition 50 10/28/2016 04/09/2017 164 days
Expedition 51 04/09/2017 06/02/2017 55 days
Expedition 52 06/02/2017 09/02/2017 92 days
Expedition 53 09/02/2017 12/14/2017 102 days
Expedition 55 02/27/2018 06/03/2018 96 days
Expedition 56 06/03/2018 10/04/2018 123 days
Expedition 57 10/04/2018 12/20/2018 77 days
Expedition 58 12/18/2018 03/14/2019 85 days
Expedition 59 03/14/2019 06/24/2019 102 days
Expedition 60 06/24/2019 10/03/2019 101 days
Expedition 61 10/03/2019 02/06/2020 126 days
Expedition 62 02/06/2020 04/17/2020 70 days

Human Research Program (HRP) Human Research Roadmap (HRR) Information
Crew health and performance is critical to successful human exploration beyond low Earth orbit. The Human Research Program (HRP) investigates and mitigates the highest risks to human health and performance, providing essential countermeasures and technologies for human space exploration. Risks include physiological and performance effects from hazards such as radiation, altered gravity, and hostile environments, as well as unique challenges in medical support, human factors, and behavioral health support. The HRP utilizes an Integrated Research Plan (IRP) to identify the approach and research activities planned to address these risks, which are assigned to specific Elements within the program. The Human Research Roadmap is the web-based tool for communicating the IRP content.

The Human Research Roadmap is located at:

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Additional Information
Managing NASA Center
Johnson Space Center (JSC)
Responsible NASA Representative
Johnson Space Center LSDA Office
Project Manager: Jessica Keune
Institutional Support
National Aeronautics and Space Administration (NASA)
Alternate Experiment Name
Proposal Date
Proposal Source
2011 Crew Health NNJ11ZSA