Document Detail


Autoregulation of the cerebral circulation during sleep in newborn lambs.
MedLine Citation:
PMID:  15760939     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Autoregulation is a vital protective mechanism that maintains stable cerebral blood flow as cerebral perfusion pressure changes. We contrasted cerebral autoregulation across sleep-wake states, as little is known about its effectiveness during sleep. Newborn lambs (n= 9) were instrumented to measure cerebral blood flow (flow probe on the superior sagittal sinus) and cerebral perfusion pressure, then studied during active sleep (AS), quiet sleep (QS) and quiet wakefulness (QW). We generated cerebral autoregulation curves by inflating an occluder cuff around the brachiocephalic artery thereby lowering cerebral perfusion pressure. Baseline cerebral blood flow was higher (P < 0.05) and cerebral vascular resistance lower (P < 0.05) in AS than in QW (76 +/- 8% and 133 +/- 15%, respectively, of the AS value, mean +/-s.d.) and in QS (66 +/- 11% and 158 +/- 30%). The autoregulation curve in AS differed from that in QS and QW in three key respects: firstly, the plateau was elevated relative to QS and QW (P < 0.05); secondly, the lower limit of the curve (breakpoint) was higher (P < 0.05) in AS (50 mmHg) than QS (45 mmHg); and thirdly, the slope of the descending limb below the breakpoint was greater (P < 0.05) in AS than QS (56% of AS) or QW (56% of AS). Although autoregulation functions in AS, the higher breakpoint and greater slope of the descending limb may place the brain at risk for vascular compromise should hypotension occur.
Authors:
Daniel A Grant; Carlo Franzini; Jennene Wild; Kellie J Eede; Adrian M Walker
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2005-03-10
Journal Detail:
Title:  The Journal of physiology     Volume:  564     ISSN:  0022-3751     ISO Abbreviation:  J. Physiol. (Lond.)     Publication Date:  2005 May 
Date Detail:
Created Date:  2005-05-16     Completed Date:  2005-08-11     Revised Date:  2009-11-18    
Medline Journal Info:
Nlm Unique ID:  0266262     Medline TA:  J Physiol     Country:  England    
Other Details:
Languages:  eng     Pagination:  923-30     Citation Subset:  IM    
Affiliation:
Ritchie Centre for Baby Health Research, Monash Institute of Medical Research, Monash Medical Centre, 246 Clayton Road, Clayton, Melbourne, Victoria, 3168, Australia.
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MeSH Terms
Descriptor/Qualifier:
Animals
Animals, Newborn
Blood Flow Velocity
Blood Pressure / physiology
Brain / blood supply*,  physiology*
Cerebrovascular Circulation / physiology*
Hemostasis / physiology
Sheep
Sleep / physiology*
Vascular Resistance / physiology
Wakefulness / physiology*
Comments/Corrections

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


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