Document Detail

Effects of periodic obstructive apneas on venous return in closed-chest dogs.
MedLine Citation:
PMID:  8342894     Owner:  NLM     Status:  MEDLINE    
With sleep apnea syndrome, mean cardiac output (CO) may fall. This implies a fall in venous return (VR) that is equal to the product of the pressure gradient for VR (GVR)--mean circulatory pressure (MCP)--right ventricular end-diastolic pressure and the conductance for VR (Gv). During airway obstruction there could also be shifts of blood volume between central and peripheral circulatory compartments. We studied these parameters in anesthetized closed-chest, spontaneously breathing dogs when hypoxia occurred (room air [RA] breathing) and when hypoxia was prevented (100% O2 breathing). Obstructive apneas were induced by completely occluding the endotracheal tube at end expiration for 1 min and allowing 1 min of spontaneous ventilation. During RA apneas, arterial PO2 decreased to 32.7 +/- 6.1 mm Hg (p < 0.01). Apnea reduced respiratory effort rate by 22.0 to 37.0% and was associated with inspiratory airway pressure swings in both RA and O2 of approximately -16.0 mm Hg. During apnea, on RA and O2 heart rate and mean arterial pressure decreased by 20 to 30 beats/min and by 8 to 12 mm Hg, respectively. On RA, CO decreased by 7.0% (not significant). In contrast, on O2, CO increased by 21.0% (p < 0.01). With RA apneas, GVR and MCP increased by 55% (p < 0.05) and Gv decreased by 63% (p < 0.05). On O2, there were no changes in GVR or Gv, and changes in CO were predictable from the baseline VR curve. With O2 there was an increase in central blood volume by 21.0% (p < 0.01) during the apneic phase.(ABSTRACT TRUNCATED AT 250 WORDS)
A Tarasiuk; S M Scharf
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S.    
Journal Detail:
Title:  The American review of respiratory disease     Volume:  148     ISSN:  0003-0805     ISO Abbreviation:  Am. Rev. Respir. Dis.     Publication Date:  1993 Aug 
Date Detail:
Created Date:  1993-08-31     Completed Date:  1993-08-31     Revised Date:  2007-11-14    
Medline Journal Info:
Nlm Unique ID:  0370523     Medline TA:  Am Rev Respir Dis     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  323-9     Citation Subset:  AIM; IM    
Division of Pulmonary and Critical Care Medicine, Albert Einstein College of Medicine, New Hyde Park, New York.
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MeSH Terms
Anoxia / physiopathology
Blood Circulation / physiology*
Blood Pressure / physiology
Blood Volume / physiology*
Carbon Dioxide / blood
Cardiac Output / physiology
Cardiac Volume / physiology*
Heart Rate / physiology
Hydrogen-Ion Concentration
Oxygen / blood
Respiration / physiology
Sleep Apnea Syndromes / physiopathology*
Stroke Volume / physiology
Veins / physiopathology*
Ventricular Function, Right / physiology
Grant Support
1 F05 TW04509-01/TW/FIC NIH HHS
Reg. No./Substance:
124-38-9/Carbon Dioxide; 7782-44-7/Oxygen

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

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