Document Detail

Comparative hemodynamic effects of periodic obstructive and simulated central apneas in sedated pigs.
MedLine Citation:
PMID:  9262444     Owner:  NLM     Status:  MEDLINE    
It has been speculated that because of increased left ventricular (LV) afterload, decreased intrathoracic pressure (ITP) is responsible for decreased cardiac output (CO) in obstructive sleep apnea. If this were true, then obstructive apnea (OA) should have a greater effect on CO than would central apnea (CA). To assess the importance of decreased ITP during OA, we studied seven preinstrumented sedated pigs with OA and simulated CA that were matched for blood gases and apnea periodicities (with 15- or 30-s apnea duration). Compared with OA, CA with 30-s apnea duration produced comparable decreases in heart rate (from baseline to end apnea: OA, 106.6 +/- 4.8 to 93.4 +/- 4.4 beats/min, P < 0.01; and CA, 111.1 +/- 6.2 to 94.0 +/- 5.2 beats/min, P < 0.01) and comparable increases in LV end-diastolic pressure and LV end-diastolic myocardial segment length but greater increases in mean arterial pressure (97.1 +/- 3.7 to 107.7 +/- 4.3 Torr, P < 0.05; and 97.3 +/- 4.8 to 119.3 +/- 7.4 Torr, P < 0.01) and systemic vascular resistance (2,577 +/- 224 to 3,346 +/- 400 dyn . s . cm-5, P < 0.01; and 2,738 +/- 294 to 5,111 +/- 1,181 dyn . s . cm-5, P < 0.01) and greater decreases in CO (3.18 +/- 0.31 to 2.74 +/- 0.26 l/min, P < 0. 05; and 3.07 +/- 0.38 to 2.30 +/- 0.36 l/min, P < 0.01) and stroke volume (32.2 +/- 2.9 to 25.9 +/- 2.4 ml, P < 0.05; and 31.5 +/- 1.9 to 19.8 +/- 3.1 ml, P < 0.01). Only CA increased LV end-systolic myocardial segment length. Similar findings were observed with 15-s apnea duration. We conclude that CA produced greater depression of CO and greater changes of afterload-related LV dysfunction than did OA. Therefore, decreased ITP was not the dominant factor determining LV function with apneas.
L Chen; S M Scharf
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Publication Detail:
Type:  Comparative Study; Journal Article; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  Journal of applied physiology (Bethesda, Md. : 1985)     Volume:  83     ISSN:  8750-7587     ISO Abbreviation:  J. Appl. Physiol.     Publication Date:  1997 Aug 
Date Detail:
Created Date:  1997-09-15     Completed Date:  1997-09-15     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:  485-94     Citation Subset:  IM    
Pulmonary and Critical Care Division, Long Island Jewish Medical Center, Long Island Campus for the Albert Einstein College of Medicine, New Hyde Park, New York 11042, USA.
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MeSH Terms
Brain / physiology*
Gases / blood
Sleep Apnea Syndromes / physiopathology*
Thorax / physiopathology
Ventricular Function, Left
Grant Support
R01 HL-49808-01A1/HL/NHLBI NIH HHS
Reg. No./Substance:

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