title: Hyperemia following aneurysmal subarachnoid hemorrhage: incidence, diagnosis, clinical features, and outcome.
abstract: OBJECTIVE
  Hyperemia is a known phenomenon after aneurysmal subarachnoid hemorrhage, but only a few reports describe and analyze hyperemia in these patients. This could be the result of diagnostic difficulties in order to identify elevated cerebral blood flow; thus, it seems that hyperemia could be an underdiagnosed clinical state. The aim of the study was to evaluate this phenomenon in comparison with clinical outcome and imaging data in order to describe the frequency of hyperemia after subarachnoid hemorrhage and maybe improve clinical diagnosis.
  
  
  METHODS
  Retrospective analysis of our cerebral blood flow and transcranial Doppler sonography data bank.
  
  
  METHODS
  . Neurosurgical/Anesthesiological intensive care unit University of Regensburg, Regensburg, Germany.
  
  
  METHODS
  A total of 37 patients were included (24 women and 13 men). All patients suffered from aneurysmal subarachnoid hemorrhage.
  
  
  RESULTS
  Standard transcranial Doppler ultrasonography, as well as the Xenon(133) clearance technique for cerebral blood flow measurements, was employed. We observed 37 increases of flow velocities in 37 patients according to Doppler ultrasonography. In order to distinguish between ischemia and hyperemia a Xenon(133) regional cerebral blood flow examination was performed. Global hyperemia was detected in 5 patients (14%). Hyperemia correlated only to favorable outcome ( p=0.01) and fewer ischemic lesions in the computed tomography ( p<0.05).
  
  
  CONCLUSIONS
  The results indicate that while global hyperemia is a frequent phenomenon that cannot be detected by standard Doppler ultrasonography or clinical examination, hyperemic cerebral blood flow values following aneurysmatic subarachnoid hemorrhage are correlated to favorable outcome.
authors.affiliation: Department of Neurosurgery, University of Regensburg, Franz-Josef-Strauss-Allee 11, 93053 Regensburg, Germany. rolf.rothoerl@klinik.uni-regensburg.de
authors.forename: Ralf Dirk
authors.initials: RD
authors.lastname: Rothoerl
authors.forename: Chris
authors.initials: C
authors.lastname: Woertgen
authors.forename: Alexander
authors.initials: A
authors.lastname: Brawanski
mesh_terms: D000328:Adult; D000368:Aged; D001783:Blood Flow Velocity; D001921:Brain / Q000098:blood supply; D002533:Cerebral Angiography; D005260:Female; D006801:Humans; D006940:Hyperemia / Q000175:diagnosis / Q000209:etiology / Q000503:physiopathology*; D007362:Intensive Care Units; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D012039:Regional Blood Flow; D012189:Retrospective Studies; D013345:Subarachnoid Hemorrhage / Q000150:complications*; D014057:Tomography, X-Ray Computed; D017585:Ultrasonography, Doppler, Transcranial; D014978:Xenon
chemical_list: D014978:Xenon