Document Detail


Effects of induced hypertension on transcranial Doppler ultrasound velocities in patients after subarachnoid hemorrhage.
MedLine Citation:
PMID:  9472884     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
BACKGROUND AND PURPOSE: Transcranial doppler ultrasound (TCD) is used after subarachnoid hemorrhage to detect cerebral vasospasm and is often treated with induced hypertension. Cerebral autoregulation, however, may be disturbed in this population, raising the possibility that TCD velocities may be elevated by induced hypertension. To study this possibility, we performed continuous TCD monitoring of the middle cerebral artery during the induction and withdrawal of induced hypertension in patients after subarachnoid hemorrhage. METHODS: Twenty-eight patients were studied during the induction and withdrawal of hypertension using primarily phenylephrine. Continuous monitoring was performed on the middle cerebral artery with the highest flow velocity. Treatment was based on rising TCD velocities or clinical evidence for cerebral vasospasm. Mean arterial pressure and mean TCD velocities were recorded every minute. A change of > 15% from starting TCD values was considered significant. Cerebral autoregulation was calculated as a percentage of intact autoregulation. Patients were subsequently divided into groups of disturbed and intact autoregulation. RESULTS: In 10 of 19 patients (53%), TCD velocities changed by > 15% and paralleled changes in mean arterial pressure. This directly altered the TCD interpretation of the grade of vasospasm in 7 of 19 patients (36%). Three additional patients had smaller absolute changes in TCD velocities. No clinical difference could be identified between patients with disturbed and intact autoregulation. CONCLUSIONS: In patients with disturbed autoregulation after subarachnoid hemorrhage, induced hypertension can alter cerebral blood flow velocities. The level of autoregulation needs to be considered when interpreting TCD velocities in patients after subarachnoid hemorrhage.
Authors:
E M Manno; D R Gress; L H Schwamm; M N Diringer; C S Ogilvy
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Publication Detail:
Type:  Journal Article    
Journal Detail:
Title:  Stroke; a journal of cerebral circulation     Volume:  29     ISSN:  0039-2499     ISO Abbreviation:  Stroke     Publication Date:  1998 Feb 
Date Detail:
Created Date:  1998-02-26     Completed Date:  1998-02-26     Revised Date:  2007-11-15    
Medline Journal Info:
Nlm Unique ID:  0235266     Medline TA:  Stroke     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  422-8     Citation Subset:  IM    
Affiliation:
Neurology/Neurosurgery Intensive Care Unit, Washington University School of Medicine, St Louis, Mo 63110, USA. mannoe@neuro.wustl.edu
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MeSH Terms
Descriptor/Qualifier:
Adult
Blood Pressure / drug effects
Female
Hemodynamics / drug effects,  physiology*
Homeostasis
Humans
Hypertension / chemically induced*
Male
Middle Aged
Patient Selection
Phenylephrine / diagnostic use*
Subarachnoid Hemorrhage / physiopathology*,  ultrasonography*
Ultrasonography, Doppler, Transcranial*
Vasoconstrictor Agents / diagnostic use*
Chemical
Reg. No./Substance:
0/Vasoconstrictor Agents; 59-42-7/Phenylephrine

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


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