Task Progress:
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Spaceflight associated neuro-ocular syndrome (SANS) is hypothesized to be caused by a weightlessness-induced headward fluid shift in the vascular and cerebrospinal fluid systems. The venous congestion countermeasure study was a three part, multi-site study with the overarching goal of assessing mechanical fluid shift countermeasures in ground based analog settings.
Part I of the study, conducted at the NASA Johnson Space Center Cardiovascular and Vision Laboratory, tested 3 mechanical countermeasures (lower body negative pressure [LBNP], veno-constrictive thigh cuffs [VTC], and impedance threshold device [ITD] resistive inspiratory breathing), individually and in combination, to reduce a posture-induced headward fluid shift that is similar in magnitude to the headward fluid shift that occurs during spaceflight. We also aimed to determine if sustaining one or more of the passive, compact countermeasures (VTC and/or ITD) after use of combined countermeasures with LBNP would maintain the footward fluid shift. Ten healthy subjects participated in this cross-over design study; testing occurred on 3 separate days within a 3 week period. On each day, cardiovascular, ocular, and noninvasive ICP measurements were taken in the seated and supine positions (baseline) and in the supine position during countermeasure application and recovery phase. On day 1, subjects were tested during individual countermeasure application (LBNP, VTC, and ITD; randomized order) and after cessation of the countermeasure to determine the recovery of physiological variables. On days 2 and 3, subjects underwent four combined countermeasure conditions (LBNP+VTC, LBNP+ITD, ITD+VTC, and LBNP+ITD+VTC), with two combined countermeasure conditions on each day in a randomized order. After each combined countermeasure data collection, one or more of the passive countermeasures (VTC and/or ITD) were maintained, and another set of measurements were taken.
Part II of the study, conducted at the University of Texas Health Science Center at Houston, tested the effects of LBNP (the most effective countermeasure as determined by Part I) on intracranial volumetrics, brain perfusion, as well as blood and CSF flow dynamics using quantitative MRI. Nine healthy subjects participated in this study; subjects underwent MRI measures in the supine posture (baseline) and in the supine posture with low-level LBNP in a randomized order. Total imaging time for each subject was approximately 2 hours.
Part III of the study, conducted at University of Texas Southwestern Institute for Exercise and Environmental Medicine and Zale Lipshy University Hospital, tested 8 hour nightly use of LBNP during bedrest. Ten healthy subjects participated in the randomized cross-over design study of 3-day supine bedrest, with and without nightly 8 hours of LBNP (randomized order). Subjects underwent baseline measures in the seated and supine postures, and thereafter measures were repeated each day of the bedrest study at 8 AM and 8 PM. During the LBNP portion of the study, subjects were placed in a next generation prototype airtight sleeping bag, sealed at the iliac crest, from 10 PM to 6 AM. The chamber was designed such that participants could lie on their back, side, or front. Throughout the entire bed rest protocol, participants were monitored to ensure strict adherence to bedrest.
Data analysis is complete for all parts of the study.
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Abstracts for Journals and Proceedings
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Kramer L, Hasan K, Macias B, Goebel-Marshall K, Laurie S, Gabr R, Hirzallah M, Kamali A, Petersen C, Chaudhary L, Petersen L, Hargens A. "Venous Congestion Countermeasure Study: Quantitative MRI Results with LBNP." Oral presentation at the 2021 NASA Human Research Program Investigators’ Workshop, Virtual, February 1-4, 2021. Abstracts. 2021 NASA Human Research Program Investigators’ Workshop, Virtual, February 1-4, 2021. , Feb-2021
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Abstracts for Journals and Proceedings
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Dias K, Hearon C Jr, Babu G, MacNamara J, Marshall J, Leidner J, Silva E, Campain J, Peters K, Levine B. "Lower Body Negative Pressure during Sleep Safely Attenuates Choroid Engorgement Associated with Simulated Microgravity." Oral presentation at the 2021 NASA Human Research Program Investigators’ Workshop, Virtual, February 1-4, 2021. Abstracts. 2021 NASA Human Research Program Investigators’ Workshop, Virtual, February 1-4, 2021. , Feb-2021
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Abstracts for Journals and Proceedings
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Dias K, Hearon C Jr, MacNamara J, Marshall J, Leidner J, Peters K, Babu G, Levine B. "Can Nightly Prolonged Lower Body Negative Pressure Preserve Plasma Volume during Simulated Microgravity?" Poster presentation at the 2021 NASA Human Research Program Investigators’ Workshop, Virtual, February 1-4, 2021. Abstracts. 2021 NASA Human Research Program Investigators’ Workshop, Virtual, February 1-4, 2021. , Feb-2021
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Abstracts for Journals and Proceedings
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Dias K, Hearon C Jr, Babu G, Marshall J, MacNamara J, Leidner J, Gillespie M, Peters K, Levine B. "Nightly Lower Body Negative Pressure Redistributes Blood Volume and Prevents Maladaptive Vascular Remodeling Induced by Microgravity." Poster presentation at American Heart Association Scientific Sessions, Virtual, November 17, 2020. American Heart Association Scientific Sessions, Virtual, November 17, 2020. , Nov-2020
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Abstracts for Journals and Proceedings
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Marshall-Goebel K, Dias K, Ebert D, Greenwald S, Hargens A, Kramer L, Laurie S, Lee S, Levine B, Macias B, Martin D, Petersen C, Petersen L, Stenger M. "Venous Congestion Countermeasure Study." Oral presentation at the 2020 NASA Human Research Program Investigators’ Workshop, Galveston, TX, January 27-30, 2020. Abstracts. 2020 NASA Human Research Program Investigators’ Workshop, Galveston, TX, January 27-30, 2020. , Jan-2020
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Abstracts for Journals and Proceedings
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Dias K, Hearon C Jr, MacNamara J, Marshall J, Leidner J, Peters K, Babu G, Levine B. "Can Nightly Prolonged Lower Body Negative Pressure Preserve Plasma Volume during Simulated Microgravity?" Poster presentation at the 2020 NASA Human Research Program Investigators’ Workshop, Galveston, TX, January 27-30, 2020. Abstracts. 2020 NASA Human Research Program Investigators’ Workshop, Galveston, TX, January 27-30, 2020. , Jan-2020
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Abstracts for Journals and Proceedings
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Babu G, Dias K, Hearon C Jr, MacNamara J, Marshall J, Leidner J, Peters K, Levine B. "Lower Body Negative Pressure during Sleep Safely Attenuates Choroid Engorgement Associated with Simulated Microgravity." Oral presentation at 2020 NASA Human Research Program Investigators’ Workshop, Galveston, TX, January 27-30, 2020. Abstracts. 2020 NASA Human Research Program Investigators’ Workshop, Galveston, TX, January 27-30, 2020. , Jan-2020
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Abstracts for Journals and Proceedings
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Ebert D, Kemp D, Danielson R, Marshall-Goebel K, Macias B, Stenger M. "Use of Otoacoustic Emissions to Evaluate Countermeasures for Spaceflight-Associated Neuro-Ocular Syndrome." Poster presentation at the 2020 NASA Human Research Program Investigators’ Workshop, Galveston, TX, January 27-30, 2020. Abstracts. 2020 NASA Human Research Program Investigators’ Workshop, Galveston, TX, January 27-30, 2020. , Jan-2020
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Articles in Peer-reviewed Journals
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Kramer LA, Hasan KM, Gabr RE, Macias BR, Marshall-Goebel K, Laurie SS, Hargens AR. "Cerebrovascular effects of lower body negative pressure at 3T MRI: Implications for long-duration space travel." J Magn Reson Imaging. 2022 Feb 4. https://doi.org/10.1002/jmri.28102 ; PMID: 35119781 , Feb-2022
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Articles in Peer-reviewed Journals
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Marshall-Goebel K, Macias BR, Laurie SS, Lee SMC, Ebert DJ, Kemp DT, Miller AE, Greenwald SH, Martin DS, Young M, Hargens AR, Levine BD, Stenger MB. "Mechanical countermeasures to headward fluid shifts." J Appl Physiol. 2021 Jun 13;130(6):1766-77. https://doi.org/10.1152/japplphysiol.00863.2020 , Jun-2021
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Articles in Peer-reviewed Journals
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Hearon CM Jr, Peters K, Dias KA, Macnamara JP, Marshall JET, Campain J, Martin D, Marshall-Goebel K, Levine BD. "Assessment of venous pressure by compression sonography of the internal jugular vein during 3 days of bed rest." Exp Physiol. 2023 Oct 12. Online ahead of print. https://doi.org/10.1113/EP091372 ; PMID: 37824038 , Oct-2023
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