Cardiovascular Models of Simulated Moon and Mars Gravities: Head-Up Tilt vs. Lower Body Unweighting

Kostas, Vladimir; Stenger, Michael B.; Knapp, Charles F.; Shapiro, Robert J.; Wang, Siqi; Diedrich, André; Evans, Joyce M.

doi:10.3357/asem.3687.2014

Cited by 10 publications

(10 citation statements)

References 2 publications

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“…Using the lower body positive pressure model, effects for total peripheral resistance were reported to be moderate (Lunar vs. 1 g) and large (Martian vs. 1 g). For thoracic impedance, data published by Kostas et al ( 2014 ) revealed moderate changes in Lunar and Martian gravities compared to 1 g.…”

Section: Resultsmentioning

confidence: 88%

“…For cardiac output as measured using the lower body positive pressure model, Kostas et al ( 2014 ) presented large effects in Lunar and Martian gravity. The effects for cardiac output as measured during head-up tilt revealed moderate changes in Lunar and small changes in Martian gravity compared to 1 g.…”

Section: Resultsmentioning

confidence: 99%

“…Widjaja et al ( 2015 ) presented extremely large effects for diastolic and systolic blood pressure values measured during a Lunar and Martian gravity parabolic flight. The study of Kostas et al ( 2014 ) presented mostly small effects for different blood pressure parameters using two different simulation models. Using the lower body positive pressure model, effects for total peripheral resistance were reported to be moderate (Lunar vs. 1 g) and large (Martian vs. 1 g).…”

Section: Resultsmentioning

confidence: 99%

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Human Biomechanical and Cardiopulmonary Responses to Partial Gravity – A Systematic Review

et al. 2017

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The European Space Agency has recently announced to progress from low Earth orbit missions on the International Space Station to other mission scenarios such as exploration of the Moon or Mars. Therefore, the Moon is considered to be the next likely target for European human space explorations. Compared to microgravity (μg), only very little is known about the physiological effects of exposure to partial gravity (μg < partial gravity <1 g). However, previous research studies and experiences made during the Apollo missions comprise a valuable source of information that should be taken into account when planning human space explorations to reduced gravity environments. This systematic review summarizes the different effects of partial gravity (0.1–0.4 g) on the human musculoskeletal, cardiovascular and respiratory systems using data collected during the Apollo missions as well as outcomes from terrestrial models of reduced gravity with either 1 g or microgravity as a control. The evidence-based findings seek to facilitate decision making concerning the best medical and exercise support to maintain astronauts' health during future missions in partial gravity. The initial search generated 1,323 publication hits. Out of these 1,323 publications, 43 studies were included into the present analysis and relevant data were extracted. None of the 43 included studies investigated long-term effects. Studies investigating the immediate effects of partial gravity exposure reveal that cardiopulmonary parameters such as heart rate, oxygen consumption, metabolic rate, and cost of transport are reduced compared to 1 g, whereas stroke volume seems to increase with decreasing gravity levels. Biomechanical studies reveal that ground reaction forces, mechanical work, stance phase duration, stride frequency, duty factor and preferred walk-to-run transition speed are reduced compared to 1 g. Partial gravity exposure below 0.4 g seems to be insufficient to maintain musculoskeletal and cardiopulmonary properties in the long-term. To compensate for the anticipated lack of mechanical and metabolic stimuli some form of exercise countermeasure appears to be necessary in order to maintain reasonable astronauts' health, and thus ensure both sufficient work performance and mission safety.

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Section: Resultsmentioning

confidence: 88%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

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Human Biomechanical and Cardiopulmonary Responses to Partial Gravity – A Systematic Review

et al. 2017

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“…24 The only available data, obtained in parabolic flight, headup tilt and lower body unweighting experiments, provided answers to short-term changes from transitioning from 1G to partial gravity levels. [94][95][96] It is critical to understand the physiologic impact of prolonged stays (days to weeks) in reduced gravity levels. What is the minimum level of gravity required to maintain fitness and prevent deconditioning?…”

Section: Incomplete Knowledge About Human Physiology In Partial Gravitymentioning

confidence: 99%

Fundamentals of Anesthesiology for Spaceflight

Komorowski

Fleming

Kirkpatrick

2016

Journal of Cardiothoracic and Vascular Anesthesia

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During future space exploration missions, the risk of medical events requiring surgery is significant, and will likely rely on anesthetic techniques. Available options during spaceflight include local, regional (nerve block) and general anesthesia. No actual invasive anesthesia was ever performed on humans in space or immediately after landing, and the safe delivery of such advanced medical care in this context is challenging. In the first section of this review, Human adaptation to the space environment is detailed, with a focus on the cardiovascular system, along with a discussion regarding which medical conditions may arise. The second part of the study focuses on discussing the extensive list of challenges associated with delivering an anesthetic procedure in space or on a foreign planetary surface. They schematically fall into two categories: missing technologies (generation of intravenous fluid, specific medical equipment, preservation of drugs…) and missing knowledge (human physiology in partial gravity, use of vasopressors, cardiovascular tolerance of general anesthesia and blood loss, choice of the most appropriate anesthetic technique, medical training). Future space exploration mis¬sions will push back the limits of human expe¬rience in maintaining health and performance of crew members in extreme settings. After more than five decades of research, our understanding of human physiology in weightlessness is advanced. Despite a number of challenges, the safe delivery of an anesthetic procedure on previously healthy individuals and given our current knowledge and technologies remains risky but could be possible even by non-anesthesiologists, and should not represent a showstopper for future space exploration missions

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“…The combination of orthostatic stress in normo- and hypovolemic men and women makes this study unique, since most studies, including our previous studies (6, 16), using upright LBPP or HUT simulated only normovolemic activity. Deconditioned physiologic responses (8, 15, 17) to orthostatic stress have been rarely studied, especially in simulating standing on the surface of Moon, the Mars and the Earth.…”

Section: Introductionmentioning

confidence: 99%

Simulations of Gravitational Stress on Normovolemic and Hypovolemic Men and Women

Zhang¹,

Knapp²,

Stenger³

et al. 2014

aviat space environ med

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Background Earth based simulations of physiologic responses to space mission activities are needed to develop prospective countermeasures. To determine whether upright lower body positive pressure (LBPP) provides a suitable space mission simulation, we investigated cardiovascular responses of normovolemic and hypovolemic, men and women, to supine and orthostatic stress, induced by head-up tilt (HUT) and upright LBPP, representing standing in lunar, Martian and Earth’s gravities. Methods Six men and six women were tested in normovolemic and hypovolemic (furosemide, intravenous, 0.5 mg/kg) conditions. Continuous electrocardiogram, blood pressure, segmental bioimpedance and stroke volume (echocardiography) were recorded supine and at lunar, Martian and Earth’s gravities (10°, 20°, 80° HUT vs. 20%, 40%, 100% body weight upright LBPP), respectively. Cardiovascular responses were assessed from mean values, spectral powers and spontaneous baroreflex parameters. Results Hypovolemia reduced plasma volume by ~10% and stroke volume by ~25% at supine and increasing orthostatic stress resulted in further reductions. Upright LBPP induced more plasma volume losses at simulated lunar and Martian gravities compared with HUT, while both techniques induced comparable central hypovolemia at each stress. Cardiovascular responses to orthostatic stress were comparable between HUT and upright LBPP in both normovolemic and hypovolemic conditions, however, hypovolemic blood pressure was greater during standing at 100% body weight compared to 80° HUT due to a greater increase of total peripheral resistance. Conclusions HUT and upright LBPP induced comparable cardiovascular responses, supporting the use of upright LBPP as a potential model to simulate activity in lunar and Martian gravities.

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Cardiovascular Models of Simulated Moon and Mars Gravities: Head-Up Tilt vs. Lower Body Unweighting

Cited by 10 publications

References 2 publications

Human Biomechanical and Cardiopulmonary Responses to Partial Gravity – A Systematic Review

Human Biomechanical and Cardiopulmonary Responses to Partial Gravity – A Systematic Review

Fundamentals of Anesthesiology for Spaceflight

Simulations of Gravitational Stress on Normovolemic and Hypovolemic Men and Women

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