Document Detail


Effect of dexmedetomidine on cerebral blood flow velocity, cerebral metabolic rate, and carbon dioxide response in normal humans.
MedLine Citation:
PMID:  18212567     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
BACKGROUND: Dexmedetomidine reduces cerebral blood flow (CBF) in humans and animals. In animal investigations, cerebral metabolic rate (CMR) was unchanged. Therefore, the authors hypothesized that dexmedetomidine would cause a decrease in the CBF/CMR ratio with even further reduction by superimposed hyperventilation. This reduction might be deleterious in patients with neurologic injuries. METHODS: Middle cerebral artery velocity (CBFV) was recorded continuously in six volunteers. CBFV, jugular bulb venous saturation (Sjvo2), CMR equivalent (CMRe), and CBFV/CMRe ratio were determined at six intervals before, during, and after administration of dexmedetomidine: (1) presedation; (2) presedation with hyperventilation; at steady state plasma levels of (3) 0.6 ng/ml and (4) 1.2 ng/ml; (5) 1.2 ng/ml with hyperventilation; and (6) 30 min after discontinuing dexmedetomidine. The slope of the arterial carbon dioxide tension (Paco2)-CBFV relation was determined presedation and at 1.2 ng/ml. RESULTS: CBFV and CMRe decreased in a dose-related manner. The CBFV/CMRe ratio was unchanged. The CBFV response to carbon dioxide decreased from 1.20 +/- 0.2 cm.s.mm Hg presedation to 0.40 +/- 0.15 cm.s.mm Hg at 1.2 ng/ml. Sjvo2 was statistically unchanged during hyperventilation at 1.2 ng/ml versus presedation (50 +/- 11 vs. 43 +/- 5%). Arousal for hyperventilation at 1.2 ng/ml resulted in increased CBFV (30 +/- 5 to 38 +/- 4) and Bispectral Index (43 +/- 10 to 94 +/- 3). CONCLUSIONS: The predicted decrease in CBFV/CMRe ratio was not observed because of an unanticipated reduction of CMRe and a decrease in the slope of the Paco2-CBFV relation. CBFV and Bispectral Index increases during arousal for hyperventilation at 1.2 ng/ml suggest that CMR-CBF coupling is preserved during dexmedetomidine administration. Further evaluation of dexmedetomidine in patients with neurologic injuries seems justified.
Authors:
John C Drummond; Andrew V Dao; David M Roth; Ching-Rong Cheng; Benjamin I Atwater; Anushirvan Minokadeh; Leonardo C Pasco; Piyush M Patel
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Anesthesiology     Volume:  108     ISSN:  1528-1175     ISO Abbreviation:  Anesthesiology     Publication Date:  2008 Feb 
Date Detail:
Created Date:  2008-01-23     Completed Date:  2008-03-05     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  1300217     Medline TA:  Anesthesiology     Country:  United States    
Other Details:
Languages:  eng     Pagination:  225-32     Citation Subset:  AIM; IM    
Affiliation:
Veterans Affairs Medical Center, San Diego, California 92161, USA. jdrummond@ucsd.edu
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MeSH Terms
Descriptor/Qualifier:
Adult
Analgesics, Non-Narcotic / pharmacology*
Blood Flow Velocity / drug effects*
Brain / drug effects,  metabolism*
Carbon Dioxide / metabolism*
Cerebrovascular Circulation / drug effects*
Dexmedetomidine / pharmacology*
Humans
Male
Middle Aged
Reference Values
Spectrophotometry, Infrared
Chemical
Reg. No./Substance:
0/Analgesics, Non-Narcotic; 113775-47-6/Dexmedetomidine; 124-38-9/Carbon Dioxide

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


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