Lower body negative pressure identifies altered central vein characteristics without accompanying changes to baroreflexes in astronauts within hours of landing
Abstract Cardiovascular deconditioning and altered baroreflexes predispose returning astronauts to Orthostatic Intolerance. We assessed 7 astronauts (1 female) before and following long-duration spaceflight (146 ± 43 days) with minimal upright posture prior to testing. We applied lower body negative...
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| Format: | Article |
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Nature Portfolio
2024-01-01
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| Series: | Scientific Reports |
| Online Access: | https://doi.org/10.1038/s41598-024-51643-1 |
| _version_ | 1797355840873693184 |
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| author | C. J. Mastrandrea D. K. Greaves J. K. Shoemaker A. P. Blaber P. Arbeille R. L. Hughson |
| author_facet | C. J. Mastrandrea D. K. Greaves J. K. Shoemaker A. P. Blaber P. Arbeille R. L. Hughson |
| author_sort | C. J. Mastrandrea |
| collection | DOAJ |
| description | Abstract Cardiovascular deconditioning and altered baroreflexes predispose returning astronauts to Orthostatic Intolerance. We assessed 7 astronauts (1 female) before and following long-duration spaceflight (146 ± 43 days) with minimal upright posture prior to testing. We applied lower body negative pressure (LBNP) of up to − 30 mmHg to supine astronauts instrumented for continual synchronous measurements of cardiovascular variables, and intermittent imaging the Portal Vein (PV) and Inferior Vena Cava (IVC). During supine rest without LBNP, postflight elevations to total peripheral resistance (TPR; 15.8 ± 4.6 vs. 20.8 ± 7.1 mmHg min/l, p < 0.05) and reductions in stroke volume (SV; 104.4 ± 16.7 vs. 87.4 ± 11.5 ml, p < 0.05) were unaccompanied by changes to heart rate (HR) or estimated central venous pressure (CVP). Small increases to systolic blood pressure (SBP) and diastolic blood pressure (DBP) were not statistically significant. Autoregressive moving average modelling (ARMA) during LBNP did not identify differences to either arterial (DBP → TPR and SBP → HR) or cardiopulmonary (CVP → TPR) baroreflexes consistent with intact cardiovascular control. On the other hand, IVC and PV diameter-CVP relationships during LBNP revealed smaller diameter for a given CVP postflight consistent with altered postflight venous wall dynamics. |
| first_indexed | 2024-03-08T14:16:58Z |
| format | Article |
| id | doaj.art-35a7fc53dd6a4f599356e95d63aeaae8 |
| institution | Directory Open Access Journal |
| issn | 2045-2322 |
| language | English |
| last_indexed | 2024-03-08T14:16:58Z |
| publishDate | 2024-01-01 |
| publisher | Nature Portfolio |
| record_format | Article |
| series | Scientific Reports |
| spelling | doaj.art-35a7fc53dd6a4f599356e95d63aeaae82024-01-14T12:19:20ZengNature PortfolioScientific Reports2045-23222024-01-0114111310.1038/s41598-024-51643-1Lower body negative pressure identifies altered central vein characteristics without accompanying changes to baroreflexes in astronauts within hours of landingC. J. Mastrandrea0D. K. Greaves1J. K. Shoemaker2A. P. Blaber3P. Arbeille4R. L. Hughson5Schlegel-UW Research Institute for AgingSchlegel-UW Research Institute for AgingSchool of Kinesiology and Department of Physiology and Pharmacology, University of Western OntarioDepartment of Biomedical Physiology and Kinesiology, Simon Fraser UniversityUnite Médecine Physiologie Spatiale, CERCOM, Faculté de Médecine-Université de ToursSchlegel-UW Research Institute for AgingAbstract Cardiovascular deconditioning and altered baroreflexes predispose returning astronauts to Orthostatic Intolerance. We assessed 7 astronauts (1 female) before and following long-duration spaceflight (146 ± 43 days) with minimal upright posture prior to testing. We applied lower body negative pressure (LBNP) of up to − 30 mmHg to supine astronauts instrumented for continual synchronous measurements of cardiovascular variables, and intermittent imaging the Portal Vein (PV) and Inferior Vena Cava (IVC). During supine rest without LBNP, postflight elevations to total peripheral resistance (TPR; 15.8 ± 4.6 vs. 20.8 ± 7.1 mmHg min/l, p < 0.05) and reductions in stroke volume (SV; 104.4 ± 16.7 vs. 87.4 ± 11.5 ml, p < 0.05) were unaccompanied by changes to heart rate (HR) or estimated central venous pressure (CVP). Small increases to systolic blood pressure (SBP) and diastolic blood pressure (DBP) were not statistically significant. Autoregressive moving average modelling (ARMA) during LBNP did not identify differences to either arterial (DBP → TPR and SBP → HR) or cardiopulmonary (CVP → TPR) baroreflexes consistent with intact cardiovascular control. On the other hand, IVC and PV diameter-CVP relationships during LBNP revealed smaller diameter for a given CVP postflight consistent with altered postflight venous wall dynamics.https://doi.org/10.1038/s41598-024-51643-1 |
| spellingShingle | C. J. Mastrandrea D. K. Greaves J. K. Shoemaker A. P. Blaber P. Arbeille R. L. Hughson Lower body negative pressure identifies altered central vein characteristics without accompanying changes to baroreflexes in astronauts within hours of landing Scientific Reports |
| title | Lower body negative pressure identifies altered central vein characteristics without accompanying changes to baroreflexes in astronauts within hours of landing |
| title_full | Lower body negative pressure identifies altered central vein characteristics without accompanying changes to baroreflexes in astronauts within hours of landing |
| title_fullStr | Lower body negative pressure identifies altered central vein characteristics without accompanying changes to baroreflexes in astronauts within hours of landing |
| title_full_unstemmed | Lower body negative pressure identifies altered central vein characteristics without accompanying changes to baroreflexes in astronauts within hours of landing |
| title_short | Lower body negative pressure identifies altered central vein characteristics without accompanying changes to baroreflexes in astronauts within hours of landing |
| title_sort | lower body negative pressure identifies altered central vein characteristics without accompanying changes to baroreflexes in astronauts within hours of landing |
| url | https://doi.org/10.1038/s41598-024-51643-1 |
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