Document Detail


Hypoxia-induced vasodilation and effects of regional phentolamine in awake patients with sleep apnea.
MedLine Citation:
PMID:  20223993     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Obstructive sleep apnea (OSA) is associated with increased sympathetic nerve activity, endothelial dysfunction, and premature cardiovascular disease. To determine whether hypoxia is associated with impaired skeletal muscle vasodilation, we compared femoral artery blood flow (ultrasound) and muscle sympathetic nerve activity (peroneal microneurography) during exposure to acute systemic hypoxia (fraction of inspired oxygen 0.1) in awake patients with OSA (n=10) and controls (n=8). To assess the role of elevated sympathetic nerve activity, in a separate group of patients with OSA (n=10) and controls (n=10) we measured brachial artery blood flow during hypoxia before and after regional alpha-adrenergic block with phentolamine. Despite elevated sympathetic activity, in OSA the vascular responses to hypoxia in the leg did not differ significantly from those in controls [P=not significant (NS)]. Following regional phentolamine, in both groups the hypoxia-induced increase in brachial blood flow was markedly enhanced (OSA pre vs. post, 84+/-13 vs. 201+/-34 ml/min, P<0.002; controls pre vs. post 62+/-8 vs. 140+/-26 ml/min, P<0.01). At end hypoxia after phentolamine, the increase of brachial blood flow above baseline was similar (OSA vs. controls +61+/-16 vs. +48+/-6%; P=NS). We conclude that despite high sympathetic vasoconstrictor tone and prominent sympathetic responses to acute hypoxia, hypoxia-induced limb vasodilation is preserved in OSA.
Authors:
Raman Moradkhan; Brett Spitnale; Patrick McQuillan; Cynthia Hogeman; Kristen S Gray; Urs A Leuenberger
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Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't     Date:  2010-03-11
Journal Detail:
Title:  Journal of applied physiology (Bethesda, Md. : 1985)     Volume:  108     ISSN:  1522-1601     ISO Abbreviation:  J. Appl. Physiol.     Publication Date:  2010 May 
Date Detail:
Created Date:  2010-05-05     Completed Date:  2010-08-12     Revised Date:  2011-07-28    
Medline Journal Info:
Nlm Unique ID:  8502536     Medline TA:  J Appl Physiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1234-40     Citation Subset:  IM    
Affiliation:
Pennsylvania State Heart and Vascular Institute, Department of Anesthesia, H047, Pennsylvania State University College of Medicine, P.O. Box 850, Hershey, PA 17033, USA.
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MeSH Terms
Descriptor/Qualifier:
Adrenergic alpha-Antagonists*
Adult
Anoxia / physiopathology*,  ultrasonography
Autonomic Nerve Block / methods*
Brachial Artery / physiopathology*,  ultrasonography
Case-Control Studies
Female
Femoral Artery / physiopathology*,  ultrasonography
Humans
Male
Middle Aged
Muscle, Skeletal / blood supply*,  innervation
Peroneal Nerve / physiopathology
Phentolamine*
Regional Blood Flow
Skin / blood supply
Sleep Apnea, Obstructive / physiopathology*,  ultrasonography
Sympathetic Nervous System / physiopathology
Ultrasonography, Doppler
Vasoconstriction
Vasodilation*
Wakefulness*
Grant Support
ID/Acronym/Agency:
C06-RR-016499/RR/NCRR NIH HHS; M01-RR-010732/RR/NCRR NIH HHS; P01-HL-077670/HL/NHLBI NIH HHS; R01-HL-068699/HL/NHLBI NIH HHS
Chemical
Reg. No./Substance:
0/Adrenergic alpha-Antagonists; 50-60-2/Phentolamine
Comments/Corrections

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