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Interactions of the human cardiopulmonary, hormonal and body fluid systems in parabolic flight

PURPOSE: Commercial parabolic flights accessible to customers with a wide range of health states will become more prevalent in the near future because of a growing private space flight sector. However, parabolic flights present the passengers’ cardiovascular system with a combination of stressors, i...

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Autores principales: Limper, U., Gauger, P., Beck, P., Krainski, F., May, F., Beck, L. E. J.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Springer Berlin Heidelberg 2014
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4019836/
https://www.ncbi.nlm.nih.gov/pubmed/24623065
http://dx.doi.org/10.1007/s00421-014-2856-3
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author Limper, U.
Gauger, P.
Beck, P.
Krainski, F.
May, F.
Beck, L. E. J.
author_facet Limper, U.
Gauger, P.
Beck, P.
Krainski, F.
May, F.
Beck, L. E. J.
author_sort Limper, U.
collection PubMed
description PURPOSE: Commercial parabolic flights accessible to customers with a wide range of health states will become more prevalent in the near future because of a growing private space flight sector. However, parabolic flights present the passengers’ cardiovascular system with a combination of stressors, including a moderately hypobaric hypoxic ambient environment (HH) and repeated gravity transitions (GT). Thus, the aim of this study was to identify unique and combined effects of HH and GT on the human cardiovascular, pulmonary and fluid regulation systems. METHODS: Cardiac index was determined by inert gas rebreathing (CI(rb)), and continuous non-invasive finger blood pressure (FBP) was repeatedly measured in 18 healthy subjects in the standing position while they were in parabolic flight at 0 and 1.8 G(z). Plasma volume (PV) and fluid regulating blood hormones were determined five times over the flight day. Eleven out of the 18 subjects were subjected to an identical test protocol in a hypobaric chamber in ambient conditions comparable to parabolic flight. RESULTS: CI(rb) in 0 G(z) decreased significantly during flight (early, 5.139 ± 1.326 L/min; late, 4.150 ± 1.082 L/min) because of a significant decrease in heart rate (HR) (early, 92 ± 15 min(−1); late, 78 ± 12 min(−1)), even though the stroke volume (SV) remained the same. HH produced a small decrease in the PV, both in the hypobaric chamber and in parabolic flight, indicating a dominating HH effect without a significant effect of GT on PV (−52 ± 34 and −115 ± 32 ml, respectively). Pulmonary tissue volume decreased in the HH conditions because of hypoxic pulmonary vasoconstriction (0.694 ± 0.185 and 0.560 ± 0.207 ml) but increased at 0 and 1.8 G(z) in parabolic flight (0.593 ± 0.181 and 0.885 ± 0.458 ml, respectively), indicating that cardiac output and arterial blood pressure rather than HH are the main factors affecting pulmonary vascular regulation in parabolic flight. CONCLUSION: HH and GT each lead to specific responses of the cardiovascular system in parabolic flight. Whereas HH seems to be mainly responsible for the PV decrease in flight, GT overrides the hypoxic pulmonary vasoconstriction induced by HH. This finding indicates the need for careful and individual medical examination and, if necessary, health status improvement for each individual considering a parabolic flight, given the effects of the combination of HH and GT in flight. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s00421-014-2856-3) contains supplementary material, which is available to authorized users.
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spelling pubmed-40198362014-05-14 Interactions of the human cardiopulmonary, hormonal and body fluid systems in parabolic flight Limper, U. Gauger, P. Beck, P. Krainski, F. May, F. Beck, L. E. J. Eur J Appl Physiol Original Article PURPOSE: Commercial parabolic flights accessible to customers with a wide range of health states will become more prevalent in the near future because of a growing private space flight sector. However, parabolic flights present the passengers’ cardiovascular system with a combination of stressors, including a moderately hypobaric hypoxic ambient environment (HH) and repeated gravity transitions (GT). Thus, the aim of this study was to identify unique and combined effects of HH and GT on the human cardiovascular, pulmonary and fluid regulation systems. METHODS: Cardiac index was determined by inert gas rebreathing (CI(rb)), and continuous non-invasive finger blood pressure (FBP) was repeatedly measured in 18 healthy subjects in the standing position while they were in parabolic flight at 0 and 1.8 G(z). Plasma volume (PV) and fluid regulating blood hormones were determined five times over the flight day. Eleven out of the 18 subjects were subjected to an identical test protocol in a hypobaric chamber in ambient conditions comparable to parabolic flight. RESULTS: CI(rb) in 0 G(z) decreased significantly during flight (early, 5.139 ± 1.326 L/min; late, 4.150 ± 1.082 L/min) because of a significant decrease in heart rate (HR) (early, 92 ± 15 min(−1); late, 78 ± 12 min(−1)), even though the stroke volume (SV) remained the same. HH produced a small decrease in the PV, both in the hypobaric chamber and in parabolic flight, indicating a dominating HH effect without a significant effect of GT on PV (−52 ± 34 and −115 ± 32 ml, respectively). Pulmonary tissue volume decreased in the HH conditions because of hypoxic pulmonary vasoconstriction (0.694 ± 0.185 and 0.560 ± 0.207 ml) but increased at 0 and 1.8 G(z) in parabolic flight (0.593 ± 0.181 and 0.885 ± 0.458 ml, respectively), indicating that cardiac output and arterial blood pressure rather than HH are the main factors affecting pulmonary vascular regulation in parabolic flight. CONCLUSION: HH and GT each lead to specific responses of the cardiovascular system in parabolic flight. Whereas HH seems to be mainly responsible for the PV decrease in flight, GT overrides the hypoxic pulmonary vasoconstriction induced by HH. This finding indicates the need for careful and individual medical examination and, if necessary, health status improvement for each individual considering a parabolic flight, given the effects of the combination of HH and GT in flight. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s00421-014-2856-3) contains supplementary material, which is available to authorized users. Springer Berlin Heidelberg 2014-03-13 2014 /pmc/articles/PMC4019836/ /pubmed/24623065 http://dx.doi.org/10.1007/s00421-014-2856-3 Text en © The Author(s) 2014 https://creativecommons.org/licenses/by/4.0/ Open AccessThis article is distributed under the terms of the Creative Commons Attribution License which permits any use, distribution, and reproduction in any medium, provided the original author(s) and the source are credited.
spellingShingle Original Article
Limper, U.
Gauger, P.
Beck, P.
Krainski, F.
May, F.
Beck, L. E. J.
Interactions of the human cardiopulmonary, hormonal and body fluid systems in parabolic flight
title Interactions of the human cardiopulmonary, hormonal and body fluid systems in parabolic flight
title_full Interactions of the human cardiopulmonary, hormonal and body fluid systems in parabolic flight
title_fullStr Interactions of the human cardiopulmonary, hormonal and body fluid systems in parabolic flight
title_full_unstemmed Interactions of the human cardiopulmonary, hormonal and body fluid systems in parabolic flight
title_short Interactions of the human cardiopulmonary, hormonal and body fluid systems in parabolic flight
title_sort interactions of the human cardiopulmonary, hormonal and body fluid systems in parabolic flight
topic Original Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4019836/
https://www.ncbi.nlm.nih.gov/pubmed/24623065
http://dx.doi.org/10.1007/s00421-014-2856-3
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