| Impaired vascular regulation in patients with obstructive sleep apnea: effects of continuous positive airway pressure treatment. | |
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MedLine Citation:
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PMID: 19745203 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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RATIONALE: Impaired endothelium-dependent vasodilation has been documented in patients with sleep apnea. This impairment may result in blood flow dysregulation during apnea-induced fluctuations in arterial blood gases. OBJECTIVES: To test the hypothesis that hypoxic and hypercapnic vasodilation in the forearm and cerebral circulation are impaired in patients with sleep apnea. METHODS: We exposed 20 patients with moderate to severe sleep apnea and 20 control subjects, to isocapnic hypoxia and hyperoxic hypercapnia. A subset of 14 patients was restudied after treatment with continuous positive airway pressure. MEASUREMENTS AND MAIN RESULTS: Cerebral flow velocity (transcranial Doppler), forearm blood flow (venous occlusion plethysmography), arterial pressure (automated sphygmomanometry), oxygen saturation (pulse oximetry), ventilation (pneumotachograph), and end-tidal oxygen and carbon dioxide tensions (expired gas analysis) were measured during three levels of hypoxia and two levels of hypercapnia. Cerebral vasodilator responses to hypoxia (-0.65 +/- 0.44 vs. -1.02 +/- 0.72 [mean +/- SD] units/% saturation; P = 0.03) and hypercapnia (2.01 +/- 0.88 vs. 2.57 +/- 0.89 units/mm Hg; P = 0.03) were smaller in patients versus control subjects. Hypoxic vasodilation in the forearm was also attenuated (-0.05 +/- 0.09 vs. -0.10 +/- 0.09 unit/% saturation; P = 0.04). Hypercapnia did not elicit forearm vasodilation in either group. Twelve weeks of continuous positive airway pressure treatment enhanced hypoxic vasodilation in the cerebral circulation (-0.83 +/- 0.32 vs. -0.46 +/- 0.29 units/% saturation; P = 0.01) and forearm (-0.19 +/- 0.15 vs. -0.02 +/- 0.08 units/% saturation; P = 0.003), and hypercapnic vasodilation in the brain showed a trend toward improvement (2.24 +/- 0.78 vs. 1.76 +/- 0.64 units/mm Hg; P = 0.06). CONCLUSIONS: Vasodilator responses to chemical stimuli in the cerebral circulation and the forearm are impaired in many patients with obstructive sleep apnea. Some of these impairments can be improved with continuous positive airway pressure. |
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Authors:
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Kevin J Reichmuth; John M Dopp; Steven R Barczi; James B Skatrud; Piotr Wojdyla; Don Hayes; Barbara J Morgan |
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Publication Detail:
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Type: Journal Article; Research Support, N.I.H., Extramural; Research Support, U.S. Gov't, Non-P.H.S. Date: 2009-09-10 |
Journal Detail:
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Title: American journal of respiratory and critical care medicine Volume: 180 ISSN: 1535-4970 ISO Abbreviation: Am. J. Respir. Crit. Care Med. Publication Date: 2009 Dec |
Date Detail:
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Created Date: 2009-11-20 Completed Date: 2009-12-07 Revised Date: 2011-03-03 |
Medline Journal Info:
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Nlm Unique ID: 9421642 Medline TA: Am J Respir Crit Care Med Country: United States |
Other Details:
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Languages: eng Pagination: 1143-50 Citation Subset: AIM; IM |
Affiliation:
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Departments of Medicine, School of Medicine and Public Health, University of Wisconsin-Madison and Middleton Veterans Administration Hospital, Madison, WI, USA. |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Adult Anoxia / physiopathology Blood Flow Velocity Blood Pressure Cerebrovascular Circulation* Continuous Positive Airway Pressure / methods* Female Follow-Up Studies Forearm / blood supply Humans Hypercapnia / physiopathology Male Oximetry Oxygen / metabolism Plethysmography / methods Sleep Apnea Syndromes / physiopathology Sleep Apnea, Obstructive / physiopathology*, therapy* Ultrasonography, Doppler, Transcranial / methods Vasodilation* |
| Grant Support | |
ID/Acronym/Agency:
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K12 RR025012/RR/NCRR NIH HHS; R01 HL074072/HL/NHLBI NIH HHS; T32 HL07654/HL/NHLBI NIH HHS |
| Chemical | |
Reg. No./Substance:
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7782-44-7/Oxygen |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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