Document Detail


Cerebral and peripheral hemodynamics and oxygenation during maximal dry breath-holds.
MedLine Citation:
PMID:  17363344     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The effects of maximal apneas on cerebral and brachial blood flow and oxygenation are unknown in humans. Middle cerebral artery blood velocity (MCAV), cerebral and muscle oxygenation (Sc(O2) and Sm(O2)) and brachial blood flow (BBF) were measured during apneas in breath-hold divers (BHD) and non-divers (ND). Brain oxyhemoglobin (O(2)Hb) was maintained in both groups until the end of apnea, whereas deoxyhemoglobin increased more in BHD. Therefore, Sc(O2) decreased more in BHD due to longer apnea duration and smaller initial MCAV increase. MCAV increased significantly more in BHD versus ND at the end of apnea. Cerebral desaturation for approximately 13% occurred at the end of apnea in BHD despite increased cerebral oxygen delivery for approximately 50%. Larger reduction in muscle O(2)Hb was found in BHD, with similar peripheral vasoconstriction. These data indicate that BHD have decreased Sc(O2) at the end of breath-hold despite large increases in MCAV. This is partly due delayed initial cerebral vasodilation. This study provides further evidence for the oxygen-conserving effect in elite divers.
Authors:
Ivan Palada; Ante Obad; Darija Bakovic; Zoran Valic; Vladimir Ivancev; Zeljko Dujic
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2007-02-08
Journal Detail:
Title:  Respiratory physiology & neurobiology     Volume:  157     ISSN:  1569-9048     ISO Abbreviation:  Respir Physiol Neurobiol     Publication Date:  2007 Aug 
Date Detail:
Created Date:  2007-05-28     Completed Date:  2007-08-02     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  101140022     Medline TA:  Respir Physiol Neurobiol     Country:  Netherlands    
Other Details:
Languages:  eng     Pagination:  374-81     Citation Subset:  IM    
Affiliation:
Department of Physiology, University of Split School of Medicine, Soltanska 2, 21000 Split, Croatia.
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MeSH Terms
Descriptor/Qualifier:
Adult
Apnea / physiopathology*
Brain / blood supply*
Cerebrovascular Circulation*
Diving / physiology
Heart Rate / physiology
Humans
Male
Middle Cerebral Artery / physiology
Muscle, Skeletal / blood supply*
Oxygen Consumption / physiology*
Oxyhemoglobins / metabolism
Regional Blood Flow
Respiration*
Spectroscopy, Near-Infrared / methods
Statistics, Nonparametric
Ultrasonography, Doppler, Transcranial / methods
Chemical
Reg. No./Substance:
0/Oxyhemoglobins

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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