Document Detail


Systemic and myocardial hemodynamics during periodic obstructive apneas in sedated pigs.
MedLine Citation:
PMID:  9516195     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
The effects of periodic obstructive apneas on systemic and myocardial hemodynamics were studied in nine preinstrumented sedated pigs under four conditions: breathing room air (RA), breathing 100% O2, breathing RA after critical coronary stenosis (CS) of the left anterior descending coronary artery, and breathing RA after autonomic blockade with hexamethonium (Hex). Apneas with RA increased mean arterial pressure (MAP; from baseline 103.0 +/- 3.5 to late apnea 123.6 +/- 7.0 Torr, P < 0.001) and coronary blood flow (CBF; late apnea 193.9 +/- 22.9% of baseline, P < 0.001) but decreased cardiac output (CO; from baseline 2.97 +/- 0.15 to late apnea 2.39 +/- 0.19 l/min, P < 0.001). Apneas with O2 increased MAP (from baseline 105.1 +/- 4.6 to late apnea 110.7 +/- 4.8 Torr, P < 0. 001). Apneas with CS produced similar increases in MAP as apneas with RA but greater decreases in CO (from baseline 3.03 +/- 0.19 to late apnea 2.1 +/- 0.15 l/min, P < 0.001). In LAD-perfused myocardium, there was decreased segmental shortening (baseline 11.0 +/- 1.5 to late apnea 7.6 +/- 2.0%, P < 0.01) and regional intramyocardial pH (baseline 7.05 +/- 0.03 to late apnea 6.72 +/- 0. 11, P < 0.001) during apneas with CS but under no other conditions. Apneas with Hex increased to the same extent as apneas with RA. Myocardial O2 demand remained unchanged during apnea relative to baseline. We conclude that obstructive apnea-induced changes in left ventricular afterload and CO are secondary to autonomic-mediated responses to hypoxemia. Increased CBF during apneas is related to regional metabolic effects of hypoxia and not to autonomic factors. In the presence of limited coronary flow reserve, decreased O2 supply during apneas can lead to myocardial ischemia, which in turn adversely affects left ventricular function.
Authors:
L Chen; S M Scharf
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Publication Detail:
Type:  Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Journal of applied physiology (Bethesda, Md. : 1985)     Volume:  84     ISSN:  8750-7587     ISO Abbreviation:  J. Appl. Physiol.     Publication Date:  1998 Apr 
Date Detail:
Created Date:  1998-05-05     Completed Date:  1998-05-05     Revised Date:  2013-09-26    
Medline Journal Info:
Nlm Unique ID:  8502536     Medline TA:  J Appl Physiol (1985)     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  1289-98     Citation Subset:  IM    
Affiliation:
Pulmonary and Critical Care Division, Long Island Jewish Medical Center, Long Island Campus for Albert Einstein College of Medicine, New Hyde Park, New York 11040, USA.
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MeSH Terms
Descriptor/Qualifier:
Animals
Blood Gas Analysis
Blood Pressure / physiology
Cardiac Output / physiology
Coronary Circulation / drug effects,  physiology*
Female
Heart Function Tests
Hemodynamics / drug effects,  physiology*
Hydrogen-Ion Concentration
Hypnotics and Sedatives / pharmacology*
Oxygen Consumption / physiology
Sleep Apnea Syndromes / physiopathology*
Swine
Grant Support
ID/Acronym/Agency:
R01 HL-49808-01A1/HL/NHLBI NIH HHS
Chemical
Reg. No./Substance:
0/Hypnotics and Sedatives

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


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