The purpose of this study was to investigate the effects of carbon dioxide (CO2) and body tilt on brain physiology in a ground-based analog of space flight. The goal was to develop a quantitative approach to measuring an individual’s brain physiological response to CO2 and fluid shifting, using modern and innovative technologies. These results will allow for precise monitoring of an individual astronaut's response to CO2 and fluid shifting given the Visual Impairment Intracranial Pressure (VIIP) syndrome may be related to these factors. This approach may also be applicable to patients on Earth with neurological conditions such as traumatic brain injury, stroke, brain hemorrhages, or hydrocephalus.
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Investigators studied the effects of CO2 and head down tilt (HDT) on brain physiology in a space flight analog ground-based analog. The major goal was to develop a quantitative approach to measuring brain physiological response to CO2 and fluid shifting, using modern technologies. These results will allow for monitoring of an individual astronaut's response to CO2 and microgravity related fluid shifts.
This study evaluated the effects of elevated carbon dioxide and head down tilt on the human body physiology, with a focus on the brain and cognitive effects. The investigators observed that head down tilt resulted in a decrease in cerebral blood flow. This may have implications for body posture in patients in various setting where cerebral blood flow may be impaired including in the intensive care unit setting, emergency rooms, and in patients with ischemic stroke, subarachnoid hemorrhage, or traumatic brain injury. Investigators determined that moderate levels of carbon dioxide were not associated with adverse cognitive effects, which is reassuring that breathing moderate elevated levels of carbon dioxide did not result in any observable cognitive effects. This may be relevant for Earth based atmospheres with ventilation that allows for accumulation of moderate CO2 in the atmosphere. Furthermore, the investigators evaluated various non-invasive technologies that may be useful for monitoring of neurological patients in various remote and austere environments. These may be useful for brain monitoring in conditions where expertise is not available on site for more invasive monitoring, or in patient populations where the risks of an invasive monitor are not warranted.
Marshall-Goebel K, Mulder E, Donoviel D, Strangman G, Suarez JI, Rao CV, et al. An international collaboration studying the physiological and anatomical cerebral effects of carbon dioxide during head-down tilt bed rest: the SPACECOT study. Journal of Applied Physiology.
2017. June 1; 122(6):1398–405.
Strangman GE, Zhang Q, Marshall-Goebel K, Mulder E, Stevens B, Clark JB, and Bershad EM. Increased cerebral blood volume pulsatility during head-down tilt with elevated carbon dioxide: The SPACE-COT Study. Journal of Applied Physiology (1985).
2017. July 1;123(1):62-70.
Kramer LA, Hasan KM, Sargsyan AE, Marshall-Goebel K, Rittweger J, Donoviel D, Higashi S, Mwangi B, Gerlach DA, and Bershad EM. Quantitative MRI volumetry, diffusivity, cerebrovascular flow and cranial hydrodynamics during head down tilt and hypercapnia: The SPACECOT study. Journal of Applied Physiology (1985).
2017. May 1; 122(5):1155-1166.
Marshall-Goebel K, Stevens B, Rao CV, Suarez JI, Calvillo E, Arbeille P, Sangi-Haghpeykar H, Donoviel DB, Mulder E, Bershad EM. Internal jugular vein volume during head-down tilt and carbon dioxide exposure in the SPACECOT study. Aerospace Medicine and Human Performance.
2018. April; 89(4):351-6. [DOI]
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: https://humanresearchroadmap.nasa.gov/
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for information of how this experiment is contributing to the HRP's path for risk reduction.