Document Detail


The relationship between cardiac output and dynamic cerebral autoregulation in humans.
MedLine Citation:
PMID:  20689094     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Cerebral autoregulation adjusts cerebrovascular resistance in the face of changing perfusion pressures to maintain relatively constant flow. Results from several studies suggest that cardiac output may also play a role. We tested the hypothesis that cerebral blood flow would autoregulate independent of changes in cardiac output. Transient systemic hypotension was induced by thigh-cuff deflation in 19 healthy volunteers (7 women) in both supine and seated positions. Mean arterial pressure (Finapres), cerebral blood flow (transcranial Doppler) in the anterior (ACA) and middle cerebral artery (MCA), beat-by-beat cardiac output (echocardiography), and end-tidal Pco(2) were measured. Autoregulation was assessed using the autoregulatory index (ARI) defined by Tiecks et al. (Tiecks FP, Lam AM, Aaslid R, Newell DW. Stroke 26: 1014-1019, 1995). Cerebral autoregulation was better in the supine position in both the ACA [supine ARI: 5.0 ± 0.21 (mean ± SE), seated ARI: 3.9 ± 0.4, P = 0.01] and MCA (supine ARI: 5.0 ± 0.2, seated ARI: 3.8 ± 0.3, P = 0.004). In contrast, cardiac output responses were not different between positions and did not correlate with cerebral blood flow ARIs. In addition, women had better autoregulation in the ACA (P = 0.046), but not the MCA, despite having the same cardiac output response. These data demonstrate cardiac output does not appear to affect the dynamic cerebral autoregulatory response to sudden hypotension in healthy controls, regardless of posture. These results also highlight the importance of considering sex when studying cerebral autoregulation.
Authors:
B M Deegan; E R Devine; M C Geraghty; E Jones; G Ólaighin; J M Serrador
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Publication Detail:
Type:  Comparative Study; Journal Article; Randomized Controlled Trial; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, Non-P.H.S.     Date:  2010-08-05
Journal Detail:
Title:  Journal of applied physiology (Bethesda, Md. : 1985)     Volume:  109     ISSN:  1522-1601     ISO Abbreviation:  J. Appl. Physiol.     Publication Date:  2010 Nov 
Date Detail:
Created Date:  2010-11-09     Completed Date:  2011-02-18     Revised Date:  2011-11-01    
Medline Journal Info:
Nlm Unique ID:  8502536     Medline TA:  J Appl Physiol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1424-31     Citation Subset:  IM    
Affiliation:
School of Engineering and Informatics, National University of Ireland Galway, Galway, Ireland.
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MeSH Terms
Descriptor/Qualifier:
Adult
Anterior Cerebral Artery / physiopathology*,  ultrasonography
Blood Pressure
Cardiac Output*
Cerebrovascular Circulation*
Echocardiography
Electrocardiography
Female
Heart Rate
Homeostasis
Humans
Hypotension / physiopathology*,  ultrasonography
Male
Middle Cerebral Artery / physiopathology*,  ultrasonography
Photoplethysmography
Regional Blood Flow
Sex Factors
Supine Position
Thigh / blood supply*
Time Factors
Ultrasonography, Doppler, Transcranial
Vascular Resistance
Young Adult

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


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