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. and Imray, Christopher H.E. Caudwell Xtreme Everest Research Group (2011) Cerebral artery dilatation maintains cerebral oxygenation at extreme altitude and in acute hypoxia--an ultrasound and MRI study Journal of Cerebral Blood Flow & Metabolism, 31, (10), pp. 2019-2029. (doi:10.1038/jcbfm.2011.81). (PMID:21654697).

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Description/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

Item Type: Article
Digital Object Identifier (DOI): doi:10.1038/jcbfm.2011.81
ISSNs: 0271-678X (print)
Subjects: Q Science > QP Physiology
Organisations: Human Development & Health
ePrint ID: 348884
Date :
Date Event
October 2011Published
Date Deposited: 21 Feb 2013 14:31
Last Modified: 17 Apr 2017 15:58
Further Information:Google Scholar
URI: http://eprints.soton.ac.uk/id/eprint/348884

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