title: Brain edema formation correlates with perfusion deficit during the first six hours after experimental subarachnoid hemorrhage in rats.
abstract: BACKGROUND
  Severe brain edema is observed in a number of patients suffering from subarachnoid hemorrhage (SAH). Little is known about its pathogenesis and time-course in the first hours after SAH. This study was performed to investigate the development of brain edema and its correlation with brain perfusion after experimental SAH.
  
  
  METHODS
  Male Sprague-Dawley rats, randomly assigned to one of six groups (n = 8), were subjected to SAH using the endovascular filament model or underwent a sham operation. Animals were sacrificed 15, 30, 60, 180 or 360 minutes after SAH. Intracranial pressure (ICP), mean arterial blood pressure (MABP), cerebral perfusion pressure (CPP) and bilateral local cerebral blood flow (LCBF) were continuously measured. Brain water content (BWC) was determined by the wet/dry-weight method.
  
  
  RESULTS
  After SAH, CPP and LCBF rapidly decreased. The decline of LCBF markedly exceeded the decline of CPP and persisted until the end of the observation period. BWC continuously increased. A significant correlation was observed between the BWC and the extent of the perfusion deficit in animals sacrificed after 180 and 360 minutes.
  
  
  CONCLUSIONS
  The significant correlation with the perfusion deficit after SAH suggests that the development of brain edema is related to the extent of ischemia and acute vasoconstriction in the first hours after SAH.
authors.affiliation: Department of Neurosurgery, University of Würzburg, Josef-Schneider-Str, 11, Würzburg, 97080, Germany. Westermaier.T@nch.uni-wuerzburg.de.
authors.forename: Thomas
authors.initials: T
authors.lastname: Westermaier
authors.forename: Christian
authors.initials: C
authors.lastname: Stetter
authors.forename: Furat
authors.initials: F
authors.lastname: Raslan
authors.forename: Giles Hamilton
authors.initials: GH
authors.lastname: Vince
authors.forename: Ralf-Ingo
authors.initials: RI
authors.lastname: Ernestus