title: Metabolic pattern of the acute phase of subarachnoid hemorrhage in a novel porcine model: studies with cerebral microdialysis with high temporal resolution.
abstract: BACKGROUND
  Aneurysmal subarachnoid hemorrhage (SAH) may produce cerebral ischemia and systemic responses including stress. To study immediate cerebral and systemic changes in response to aneurysm rupture, animal models are needed.
  
  
  OBJECTIVE
  To study early cerebral energy changes in an animal model.
  
  
  METHODS
  Experimental SAH was induced in 11 pigs by autologous blood injection to the anterior skull base, with simultaneous control of intracranial and cerebral perfusion pressures. Intracerebral microdialysis was used to monitor concentrations of glucose, pyruvate and lactate.
  
  
  RESULTS
  In nine of the pigs, a pattern of transient ischemia was produced, with a dramatic reduction of cerebral perfusion pressure soon after blood injection, associated with a quick glucose and pyruvate decrease. This was followed by a lactate increase and a delayed pyruvate increase, producing a marked but short elevation of the lactate/pyruvate ratio. Glucose, pyruvate, lactate and lactate/pyruvate ratio thereafter returned toward baseline. The two remaining pigs had a more severe metabolic reaction with glucose and pyruvate rapidly decreasing to undetectable levels while lactate increased and remained elevated, suggesting persisting ischemia.
  
  
  CONCLUSIONS
  The animal model simulates the conditions of SAH not only by deposition of blood in the basal cisterns, but also creating the transient global ischemic impact of aneurysmal SAH. The metabolic cerebral changes suggest immediate transient substrate failure followed by hypermetabolism of glucose upon reperfusion. The model has features that resemble spontaneous bleeding, and is suitable for future research of the early cerebral and systemic responses to SAH that are difficult to study in humans.
authors.affiliation: Department of Neuroscience, section of Neurosurgery, Uppsala University, Uppsala, Sweden.
authors.forename: Christoffer
authors.initials: C
authors.lastname: Nyberg
authors.affiliation: Department of Surgical Sciences, section of Anesthesiology and Intensive care, Uppsala University, Uppsala, Sweden.
authors.forename: Torbjörn
authors.initials: T
authors.lastname: Karlsson
authors.affiliation: Department of Neuroscience, section of Neurosurgery, Uppsala University, Uppsala, Sweden.
authors.forename: Lars
authors.initials: L
authors.lastname: Hillered
authors.affiliation: Department of Neuroscience, section of Neurosurgery, Uppsala University, Uppsala, Sweden.
authors.forename: Elisabeth
authors.initials: E
authors.lastname: Ronne Engström
mesh_terms: D000818:Animals; D062186:Arterial Pressure; D002560:Cerebrovascular Circulation; D054022:Cerebrum / Q000000981:diagnostic imaging / Q000378:metabolism* / Q000473:pathology; D004195:Disease Models, Animal; D005260:Female; D007427:Intracranial Pressure; D008297:Male; D017551:Microdialysis; D010477:Perfusion; D011180:Postmortem Changes; D013345:Subarachnoid Hemorrhage / Q000000981:diagnostic imaging / Q000378:metabolism* / Q000503:physiopathology; D034421:Sus scrofa; D013997:Time Factors; D014057:Tomography, X-Ray Computed