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Cerebral artery dilatation maintains cerebral oxygenation at extreme altitude and in acute hypoxia—an ultrasound and MRI study

Transcranial Doppler is a widely used noninvasive technique for assessing cerebral artery blood flow. All previous high altitude studies assessing cerebral blood flow (CBF) in the field that have used Doppler to measure arterial blood velocity have assumed vessel diameter to not alter. Here, we repo...

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Autores principales: Wilson, Mark H, Edsell, Mark E G, Davagnanam, Indran, Hirani, Shashivadan P, Martin, Dan S, Levett, Denny Z H, Thornton, John S, Golay, Xavier, Strycharczuk, Lisa, Newman, Stanton P, Montgomery, Hugh E, Grocott, Mike P W, Imray, Christopher H E
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Nature Publishing Group 2011
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3208157/
https://www.ncbi.nlm.nih.gov/pubmed/21654697
http://dx.doi.org/10.1038/jcbfm.2011.81
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author Wilson, Mark H
Edsell, Mark E G
Davagnanam, Indran
Hirani, Shashivadan P
Martin, Dan S
Levett, Denny Z H
Thornton, John S
Golay, Xavier
Strycharczuk, Lisa
Newman, Stanton P
Montgomery, Hugh E
Grocott, Mike P W
Imray, Christopher H E
author_facet Wilson, Mark H
Edsell, Mark E G
Davagnanam, Indran
Hirani, Shashivadan P
Martin, Dan S
Levett, Denny Z H
Thornton, John S
Golay, Xavier
Strycharczuk, Lisa
Newman, Stanton P
Montgomery, Hugh E
Grocott, Mike P W
Imray, Christopher H E
author_sort Wilson, Mark H
collection PubMed
description Transcranial Doppler is a widely used noninvasive technique for assessing cerebral artery blood flow. All previous high altitude studies assessing cerebral blood flow (CBF) in the field that have used Doppler to measure arterial blood velocity have assumed vessel diameter to not alter. Here, we report two studies that demonstrate this is not the case. First, we report the highest recorded study of CBF (7,950 m on Everest) and demonstrate that above 5,300 m, middle cerebral artery (MCA) diameter increases (n=24 at 5,300 m, 14 at 6,400 m, and 5 at 7,950 m). Mean MCA diameter at sea level was 5.30 mm, at 5,300 m was 5.23 mm, at 6,400 m was 6.66 mm, and at 7,950 m was 9.34 mm (P<0.001 for change between 5,300 and 7,950 m). The dilatation at 7,950 m reversed with oxygen. Second, we confirm this dilatation by demonstrating the same effect (and correlating it with ultrasound) during hypoxia (FiO(2)=12% for 3 hours) in a 3-T magnetic resonance imaging study at sea level (n=7). From these results, we conclude that it cannot be assumed that cerebral artery diameter is constant, especially during alterations of inspired oxygen partial pressure, and that transcranial 2D ultrasound is a technique that can be used at the bedside or in the remote setting to assess MCA caliber.
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spelling pubmed-32081572011-11-30 Cerebral artery dilatation maintains cerebral oxygenation at extreme altitude and in acute hypoxia—an ultrasound and MRI study Wilson, Mark H Edsell, Mark E G Davagnanam, Indran Hirani, Shashivadan P Martin, Dan S Levett, Denny Z H Thornton, John S Golay, Xavier Strycharczuk, Lisa Newman, Stanton P Montgomery, Hugh E Grocott, Mike P W Imray, Christopher H E J Cereb Blood Flow Metab Original Article Transcranial Doppler is a widely used noninvasive technique for assessing cerebral artery blood flow. All previous high altitude studies assessing cerebral blood flow (CBF) in the field that have used Doppler to measure arterial blood velocity have assumed vessel diameter to not alter. Here, we report two studies that demonstrate this is not the case. First, we report the highest recorded study of CBF (7,950 m on Everest) and demonstrate that above 5,300 m, middle cerebral artery (MCA) diameter increases (n=24 at 5,300 m, 14 at 6,400 m, and 5 at 7,950 m). Mean MCA diameter at sea level was 5.30 mm, at 5,300 m was 5.23 mm, at 6,400 m was 6.66 mm, and at 7,950 m was 9.34 mm (P<0.001 for change between 5,300 and 7,950 m). The dilatation at 7,950 m reversed with oxygen. Second, we confirm this dilatation by demonstrating the same effect (and correlating it with ultrasound) during hypoxia (FiO(2)=12% for 3 hours) in a 3-T magnetic resonance imaging study at sea level (n=7). From these results, we conclude that it cannot be assumed that cerebral artery diameter is constant, especially during alterations of inspired oxygen partial pressure, and that transcranial 2D ultrasound is a technique that can be used at the bedside or in the remote setting to assess MCA caliber. Nature Publishing Group 2011-10 2011-06-08 /pmc/articles/PMC3208157/ /pubmed/21654697 http://dx.doi.org/10.1038/jcbfm.2011.81 Text en Copyright © 2011 International Society for Cerebral Blood Flow & Metabolism, Inc. http://creativecommons.org/licenses/by-nc-nd/3.0/ This work is licensed under the Creative Commons Attribution-NonCommercial-No Derivative Works 3.0 Unported License. To view a copy of this license, visit http://creativecommons.org/licenses/by-nc-nd/3.0/
spellingShingle Original Article
Wilson, Mark H
Edsell, Mark E G
Davagnanam, Indran
Hirani, Shashivadan P
Martin, Dan S
Levett, Denny Z H
Thornton, John S
Golay, Xavier
Strycharczuk, Lisa
Newman, Stanton P
Montgomery, Hugh E
Grocott, Mike P W
Imray, Christopher H E
Cerebral artery dilatation maintains cerebral oxygenation at extreme altitude and in acute hypoxia—an ultrasound and MRI study
title Cerebral artery dilatation maintains cerebral oxygenation at extreme altitude and in acute hypoxia—an ultrasound and MRI study
title_full Cerebral artery dilatation maintains cerebral oxygenation at extreme altitude and in acute hypoxia—an ultrasound and MRI study
title_fullStr Cerebral artery dilatation maintains cerebral oxygenation at extreme altitude and in acute hypoxia—an ultrasound and MRI study
title_full_unstemmed Cerebral artery dilatation maintains cerebral oxygenation at extreme altitude and in acute hypoxia—an ultrasound and MRI study
title_short Cerebral artery dilatation maintains cerebral oxygenation at extreme altitude and in acute hypoxia—an ultrasound and MRI study
title_sort cerebral artery dilatation maintains cerebral oxygenation at extreme altitude and in acute hypoxia—an ultrasound and mri study
topic Original Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3208157/
https://www.ncbi.nlm.nih.gov/pubmed/21654697
http://dx.doi.org/10.1038/jcbfm.2011.81
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