Document Detail


Continuous time-domain analysis of cerebrovascular autoregulation using near-infrared spectroscopy.
MedLine Citation:
PMID:  17761921     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
BACKGROUND AND PURPOSE: Assessment of autoregulation in the time domain is a promising monitoring method for actively optimizating cerebral perfusion pressure (CPP) in critically ill patients. The ability to detect loss of autoregulatory vasoreactivity to spontaneous fluctuations in CPP was tested with a new time-domain method that used near-infrared spectroscopic measurements of tissue oxyhemoglobin saturation in an infant animal model.
METHODS: Piglets were made progressively hypotensive over 4 to 5 hours by inflation of a balloon catheter in the inferior vena cava, and the breakpoint of autoregulation was determined using laser-Doppler flowmetry. The cerebral oximetry index (COx) was determined as a moving linear correlation coefficient between CPP and INVOS cerebral oximeter waveforms during 300-second periods. A laser-Doppler derived time-domain analysis of spontaneous autoregulation with the same parameters (LDx) was also determined.
RESULTS: An increase in the correlation coefficient between cerebral oximetry values and dynamic CPP fluctuations, indicative of a pressure-passive relationship, occurred when CPP was below the steady state autoregulatory breakpoint. This COx had 92% sensitivity (73% to 99%) and 63% specificity (48% to 76%) for detecting loss of autoregulation attributable to hypotension when COx was above a threshold of 0.36. The area under the receiver-operator characteristics curve for the COx was 0.89. COx correlated with LDx when values were sorted and averaged according to the CPP at which they were obtained (r=0.67).
CONCLUSIONS: The COx is sensitive for loss of autoregulation attributable to hypotension and is a promising monitoring tool for determining optimal CPP for patients with acute brain injury.
Authors:
Ken M Brady; Jennifer K Lee; Kathleen K Kibler; Piotr Smielewski; Marek Czosnyka; R Blaine Easley; Raymond C Koehler; Donald H Shaffner
Publication Detail:
Type:  Journal Article; Research Support, N.I.H., Extramural; Research Support, Non-U.S. Gov't     Date:  2007-08-30
Journal Detail:
Title:  Stroke; a journal of cerebral circulation     Volume:  38     ISSN:  1524-4628     ISO Abbreviation:  Stroke     Publication Date:  2007 Oct 
Date Detail:
Created Date:  2007-09-25     Completed Date:  2007-10-18     Revised Date:  2014-02-19    
Medline Journal Info:
Nlm Unique ID:  0235266     Medline TA:  Stroke     Country:  United States    
Other Details:
Languages:  eng     Pagination:  2818-25     Citation Subset:  IM    
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MeSH Terms
Descriptor/Qualifier:
Acute Disease
Age Factors
Animals
Brain Injuries / diagnosis,  physiopathology*
Cerebrovascular Circulation / physiology*
Disease Models, Animal
Homeostasis / physiology
Hypotension / diagnosis,  physiopathology*
Laser-Doppler Flowmetry
Monitoring, Physiologic / instrumentation*,  methods
Oximetry
Sensitivity and Specificity
Spectroscopy, Near-Infrared / methods*
Swine
Grant Support
ID/Acronym/Agency:
G9439390//Medical Research Council; NS20020/NS/NINDS NIH HHS; P01 NS020020-240002/NS/NINDS NIH HHS
Comments/Corrections

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