| Consequences of cardiovascular adaptation to spaceflight: implications for the use of pharmacological countermeasures. | |
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MedLine Citation:
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PMID: 16038093 Owner: NASA Status: MEDLINE |
Abstract/OtherAbstract:
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There is little evidence obtained from space flight to support the notion that occurrence of cardiac dysrhythmias, impaired cardiac and vascular function, and manifestation of asymptomatic cardiovascular disease represent serious risks during space flight. Therefore, the development of orthostatic hypotension and instability immediately after return from spaceflight probably reflect the most significant operational risks associated with the cardiovascular system of astronauts. Significant reductions in stroke volume and lower reserve for increasing peripheral vascular resistance contribute to ineffective maintenance of systemic arterial blood pressure during standing after spaceflight despite compensatory elevations in heart rate. The primary mechanism underlying reduced stroke volume appears to be a reduction in preload associated with less circulating blood volume while inadequate peripheral vasoconstriction may be caused partly by hyporeactivity of receptors that control arterial smooth muscle function. A focus for development of future countermeasures for hemodynamic responses to central hypovolemia includes the potential application of pharmacological agents that specifically target and restore blood volume (e.g., fludrocortisone, electrolyte-containing beverages) and reserve for vasoconstriction (e.g., midodrine, vasopressin). Based on systematic evaluations, acute physical exercise designed to elicit maximal effort or inspiratory resistance have shown promise as successful countermeasures that provide protection against development of orthostatic hypotension and intolerance without potential risks and side effects associated with specific pharmacological interventions. |
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Authors:
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Victor A Convertino |
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Publication Detail:
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Type: Journal Article; Review |
Journal Detail:
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Title: Gravitational and space biology bulletin : publication of the American Society for Gravitational and Space Biology Volume: 18 ISSN: 1089-988X ISO Abbreviation: Gravit Space Biol Bull Publication Date: 2005 Jun |
Date Detail:
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Created Date: 2005-07-24 Completed Date: 2005-10-21 Revised Date: 2009-04-08 |
Medline Journal Info:
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Nlm Unique ID: 9816128 Medline TA: Gravit Space Biol Bull Country: United States |
Other Details:
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Languages: eng Pagination: 59-69 Citation Subset: S |
Affiliation:
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U.S. Army Institute of Surgical Research, Fort Sam Houston, Texas 78234-6513, USA. victor.convertino@amedd.army.mil |
Space Flight Mission:
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Flight Experiment; STS Shuttle Project; manned; short duration |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Adaptation, Physiological Adrenergic alpha-Agonists / therapeutic use Aerospace Medicine Astronauts Blood Pressure / physiology Blood Volume / physiology Cardiac Output / physiology Cardiovascular Deconditioning / drug effects, physiology Exercise / physiology Fludrocortisone / therapeutic use Hemodynamics / physiology* Humans Hypotension, Orthostatic / drug therapy*, etiology Midodrine / therapeutic use Sodium Chloride / therapeutic use Space Flight* Stroke Volume / physiology Vascular Resistance / physiology Weightlessness / adverse effects* Weightlessness Countermeasures* |
| Chemical | |
Reg. No./Substance:
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0/Adrenergic alpha-Agonists; 127-31-1/Fludrocortisone; 42794-76-3/Midodrine; 7647-14-5/Sodium Chloride |
| Investigator | |
Investigator/Affiliation:
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V A Convertino / US Army Inst Surgical Res, Ft Sam Houston, TX |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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