White Mountain Expedition 2019: The Impact of Sustained Hypoxia on Cerebral Blood Flow Responses and Tolerance to Simulated Hemorrhage

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dc.creatorRosenberg, Alexander
dc.creatorAnderson, Garen K.
dc.creatorBarnes, Haley J.
dc.creatorBird, Jordan D.
dc.creatorPentz, Brandon
dc.creatorByman, Britta
dc.creatorJendzjowsky, Nicholas
dc.creatorWilson, Richard
dc.creatorDay, Trevor
dc.creatorRickards, Caroline
dc.date.accessioned2021-04-30T15:01:52Z
dc.date.available2021-04-30T15:01:52Z
dc.date.issued2021
dc.descriptionResearch Appreciation Day Award Winner - 2021 Graduate School of Biomedical Sciences Postdoctoral Oral Presentations - 1st Place
dc.descriptionResearch Appreciation Day Award Winner - 2021 Graduate School of Biomedical Sciences Postdoctoral Oral Presentations - 1st Placeen_US
dc.description.abstractTrauma-induced hemorrhage can occur at high altitude (HA) from a variety of causes, including battlefield injuries, vehicle/air accidents, and major falls. As the partial pressure of oxygen decreases with ascent to altitude, compensatory increases in cerebral blood flow (CBF) and oxygen delivery occur to preserve cerebral tissue oxygenation (ScO2). Accordingly, we hypothesized that tolerance to simulated hemorrhage (via lower body negative pressure, LBNP) following sustained exposure to HA would be similar compared to low altitude (LA) due to compensatory increases in CBF and oxygen delivery, and the subsequent preservation of ScO2. Healthy adults (N=8;4F/4M) participated in LBNP protocols to presyncope at LA (1045m) and at HA (3800m) following 5-7 days of acclimatization. Arterial pressure, heart rate (HR), stroke volume (SV), internal carotid artery blood flow (ICA BF), and ScO2 were measured continuously. Time to presyncope was similar between conditions (LA:1276±304s vs. HA:1208±306s;P=0.58). Similar maximal responses to LBNP were observed at LA and HA in mean arterial pressure (LA:-16±6% vs. HA:-16±6%;P=0.85), SV (LA:-57±14% vs. HA:-60±13%;P=0.39), and HR (LA:+69±33% vs. HA:+65±23%;P=0.71). ICA BF was elevated at baseline at HA vs. LA (P=0.04) and decreased with LBNP under both conditions (P< 0.0001). There was no effect of altitude (P=0.59) on ScO2, which decreased with LBNP under both conditions (P=0.09). Sustained exposure to hypoxia at an altitude of 3800m does not affect tolerance to simulated hemorrhage in adults, which may be due to 1) similar cardiovascular reflex responses, and 2) compensatory increases in CBF and subsequent preservation of ScO2.
dc.description.sponsorshipFunding for this study was provided, in part, by an American Heart Association Grant-in-Aid to CAR (GRNT 17GRNT33671110), and training fellowships awarded to GKA through a National Institutes of Health-supported Neurobiology of Aging Training Grant (T32 A
dc.identifier.urihttps://hdl.handle.net/20.500.12503/30507
dc.language.isoen
dc.titleWhite Mountain Expedition 2019: The Impact of Sustained Hypoxia on Cerebral Blood Flow Responses and Tolerance to Simulated Hemorrhage
dc.typepresentation
dc.type.materialtext

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