Document Detail


Effects of early and late intravenous norepinephrine infusion on cerebral perfusion, microcirculation, brain-tissue oxygenation, and edema formation in brain-injured rats.
MedLine Citation:
PMID:  12973182     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
OBJECTIVES: Reduction of cerebral perfusion during the early phase after traumatic brain injury is followed by a later phase of normal to increased perfusion. Thus, pharmacologically elevating mean arterial blood pressure with the aim of improving cerebral perfusion may exert different time-dependent effects on cortical perfusion, microcirculation, tissue oxygenation and brain edema formation after traumatic brain injury. DESIGN: Randomized, placebo-controlled trial. SETTING: Experimental laboratory at a university hospital. SUBJECTS: A total of 37 male Sprague-Dawley rats subjected to a focal cortical contusion. INTERVENTIONS: At 4 or 24 hrs after focal traumatic brain injury, mean arterial blood pressure was increased to 120 mm Hg for 90 mins by infusing norepinephrine. In rats receiving physiologic saline, mean arterial blood pressure remained unchanged. In the first series, pericontusional cortical perfusion was measured using the laser Doppler flowmetry scanning technique before injury and before, during, and after the infusion period. In a second series, intracranial and cerebral perfusion pressure and intraparenchymal perfusion and tissue oxygen measured within the contused and pericontusional cortex were recorded continuously before, during, and after norepinephrine infusion. Changes in cortical microcirculation were investigated by orthogonal polarization spectral imaging. At the end of each experiment, hemispheric swelling and water content were determined gravimetrically. MEASUREMENTS AND MAIN RESULTS: At 4 and 24 hrs after traumatic brain injury, intravenous norepinephrine significantly increased pericontusional cortical perfusion, which was also reflected by an increase in diameters and flow velocities of pericontusional arterioles and venules. Cerebral perfusion pressure and intraparenchymal perfusion and tissue oxygen were significantly increased during norepinephrine infusion at 4 and 24 hrs. Hemispheric swelling and water content showed no difference between the groups. CONCLUSIONS: After cortical impact injury, early and late intravenous norepinephrine infusion pressure-dependently increased cerebral perfusion and tissue oxygenation without aggravating or reducing brain edema formation. Future studies are warranted to determine long-term changes of short and prolonged norepinephrine-induced increases in mean arterial blood pressure and cerebral perfusion pressure.
Authors:
Stefan-Nikolaus Kroppenstedt; Ulrich-Wilhelm Thomale; Martin Griebenow; Oliver W Sakowitz; Klaus-Dieter Schaser; Petra S Mayr; Andreas W Unterberg; John F Stover
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Critical care medicine     Volume:  31     ISSN:  0090-3493     ISO Abbreviation:  Crit. Care Med.     Publication Date:  2003 Aug 
Date Detail:
Created Date:  2003-09-15     Completed Date:  2003-10-07     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0355501     Medline TA:  Crit Care Med     Country:  United States    
Other Details:
Languages:  eng     Pagination:  2211-21     Citation Subset:  AIM; IM    
Affiliation:
Department of Neurosurgery, Charité, Virchow Medical Center, Humboldt University, Berlin, Germany.
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MeSH Terms
Descriptor/Qualifier:
Animals
Blood Gas Analysis
Blood Glucose
Brain Edema / metabolism*
Brain Injuries / metabolism*
Cerebral Cortex / blood supply*,  drug effects
Cerebrovascular Circulation / drug effects*
Disease Models, Animal
Drug Administration Schedule
Infusions, Intravenous
Laser-Doppler Flowmetry
Male
Microcirculation / drug effects
Norepinephrine / administration & dosage,  pharmacology*
Random Allocation
Rats
Rats, Sprague-Dawley
Regional Blood Flow
Vasoconstrictor Agents / administration & dosage,  pharmacology*
Chemical
Reg. No./Substance:
0/Blood Glucose; 0/Vasoconstrictor Agents; 51-41-2/Norepinephrine

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