Cerebral artery dilatation maintains cerebral oxygenation at extreme altitude and in acute hypoxiaan ultrasound and MRI study

Mark H. Wilson, Mark E G Edsell, Indran Davagnanam, Shashivadan P. Hirani, Dan S. Martin, Denny Z H Levett, John S. Thornton, Xavier Golay, Lisa Strycharczuk, Stanton P. Newman, Hugh E. Montgomery, Mike P W Grocott, Christopher H E Imray

Research output: Contribution to journalArticle

Abstract

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.

Original languageEnglish (US)
Pages (from-to)2019-2029
Number of pages11
JournalJournal of Cerebral Blood Flow and Metabolism
Volume31
Issue number10
DOIs
StatePublished - Oct 2011
Externally publishedYes

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Cerebrovascular Circulation
Cerebral Arteries
Middle Cerebral Artery
Dilatation
Oceans and Seas
Oxygen
Partial Pressure
Magnetic Resonance Imaging

Keywords

  • brain imaging
  • cerebral blood flow
  • high altitude
  • MRI
  • transcranial Doppler

ASJC Scopus subject areas

  • Cardiology and Cardiovascular Medicine
  • Clinical Neurology
  • Neurology

Cite this

Wilson, M. H., Edsell, M. E. G., Davagnanam, I., Hirani, S. P., Martin, D. S., Levett, D. Z. H., ... Imray, C. H. E. (2011). Cerebral artery dilatation maintains cerebral oxygenation at extreme altitude and in acute hypoxiaan ultrasound and MRI study. Journal of Cerebral Blood Flow and Metabolism, 31(10), 2019-2029. https://doi.org/10.1038/jcbfm.2011.81

Cerebral artery dilatation maintains cerebral oxygenation at extreme altitude and in acute hypoxiaan 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.

In: Journal of Cerebral Blood Flow and Metabolism, Vol. 31, No. 10, 10.2011, p. 2019-2029.

Research output: Contribution to journalArticle

Wilson, MH, Edsell, MEG, Davagnanam, I, Hirani, SP, Martin, DS, Levett, DZH, Thornton, JS, Golay, X, Strycharczuk, L, Newman, SP, Montgomery, HE, Grocott, MPW & Imray, CHE 2011, 'Cerebral artery dilatation maintains cerebral oxygenation at extreme altitude and in acute hypoxiaan ultrasound and MRI study', Journal of Cerebral Blood Flow and Metabolism, vol. 31, no. 10, pp. 2019-2029. https://doi.org/10.1038/jcbfm.2011.81
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 hypoxiaan ultrasound and MRI study. In: Journal of Cerebral Blood Flow and Metabolism. 2011 ; Vol. 31, No. 10. pp. 2019-2029.
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abstract = "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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AU - Martin, Dan S.

AU - Levett, Denny Z H

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AU - Strycharczuk, Lisa

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