Medizinische Universität Graz Austria/Österreich - Forschungsportal - Medical University of Graz
Gewählte Publikation:
SHR Neuro Krebs Kardio Lipid Stoffw Microb
Loeppky, JA; Roach, RC; Maes, D; Hinghofer-Szalkay, H; Roessler, A; Gates, L; Fletcher, ER; Icenogle, MV.
Role of hypobaria in fluid balance response to hypoxia.
High Alt Med Biol. 2005; 6(1): 60-71.
Doi: 10.1089/ham.2005.6.60
Web of Science
PubMed
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FullText_MUG
- Co-Autor*innen der Med Uni Graz
- Hinghofer-Szalkay Helmut
- Rössler Andreas
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- Abstract:
- To estimate the separate and combined effects of reduced P(B) and O2 levels on body fluid balance and regulating hormones, measurements were made during reduced PB (altitude, ALT; P(B) = 432 mm Hg, F(I(O2)) = 0.207), reduced inspired O2 concentration (normobaric hypoxia, HYX; P(B) = 614 mm Hg, F(I(O2)) = 0.142), and lowered ambient pressure without hypoxia (normoxic hypobaria HYB; P(B) = 434 mm Hg, F(I(O2)) = 0.296). Nine fit and healthy young men were exposed to these conditions for 10 h in a decompression chamber. Lake Louise AMS scores, urine collections, and blood samples were obtained every 3 h, with recovery measurements 2 h after exposure. AMS was significantly greater during ALT than HYX, as previously reported (J. Appl. Physiol. 81:1908-1910. 1996), because the combination of reduced P(B) and P(O2) over the 10 h favored fluid retention by reducing urine volume, while plasma volume (PV) remained higher than during HYX. At ALT the plasma Na+ fell significantly at 6 h, probably from dilution of extracellular fluid, and antidiuretic hormone (ADH) was highest (p = 0.006 versus HYB). The PV, urine flow, free water clearance, and plasma renin activity (PRA) rose significantly during recovery from ALT as AMS symptoms subsided, suggesting increased intravascular fluid and reduced adrenergic tone. During HYB, the plasma aldosterone (ALDO) and K+ levels were significantly elevated, and PRA was highest and ADH lowest, without fluid retention. During HYX, fluid balance was similar to HYB, but PV and ALDO were significantly lower, and ALDO increased significantly in recovery from HYX. The fluid retention at ALT in AMS-susceptible subjects appears related to a synergistic interaction involving reduced P(B) and ADH and ALDO.
- Find related publications in this database (using NLM MeSH Indexing)
- Acclimatization -
- Acute Disease -
- Adult -
- Aldosterone - blood
- Altitude - blood
- Altitude Sickness - blood
- Analysis of Variance - blood
- Arginine Vasopressin - blood
- Atrial Natriuretic Factor - blood
- Body Fluids - blood
- Humans - blood
- Male - blood
- New Mexico - blood
- Norepinephrine - blood
- Renin - blood
- Water-Electrolyte Balance - blood
- Water-Electrolyte Imbalance - blood
- Find related publications in this database (Keywords)
- acute mountain sickness (AMS)
- aldosterone
- antidiuretic hormone
- fluid balance
- hypobaria
- hypoxia
- osmolar clearance
- plasma electrolytes
- plasma renin