title: Optimal hemoglobin concentration in patients with subarachnoid hemorrhage, acute ischemic stroke and traumatic brain injury.
abstract: OBJECTIVE
  The review outlines recent clinical and experimental studies regarding the effects of red blood-cell transfusion on clinical outcome in neurocritical patients, including patients with subarachnoid hemorrhage, acute ischemic stroke and traumatic brain injury. Optimal hemoglobin transfusion trigger and the role of other transfusion indicators for neurocritical patients are discussed.
  
  
  RESULTS
  Acute anemia (hemoglobin levels near 7 g/dl) is well tolerated by healthy subjects, but extreme anemia might negatively affect clinical outcome of neurocritical patients. Conversely, high hemoglobin levels, attained by means other than red blood-cell transfusion, improve clinical outcome, whereas red blood-cell transfusion is associated with poorer clinical outcome (mortality, length of stay and disability) in patients presenting subarachnoid hemorrhage, acute ischemic stroke and traumatic brain injury. Studies defining the optimal hemoglobin concentration in neurocritical patients are lacking, but a restrictive transfusion policy seems to be safe and is often recommended. In the near future, signals coming from the brain, such as brain tissue oxygen tension and regional cerebral oxygen saturation, might potentially be developed into transfusion triggers.
  
  
  CONCLUSIONS
  Both severe anemia and red blood-cell transfusion may negatively influence clinical outcome in neurocritical patients. Acceptance of low hemoglobin concentrations may be justified by avoiding negative transfusion effects. No evidence-based transfusion trigger in neurocritical patients can be recommended.
authors.affiliation: Neurocritical Care Division, Hospital Universitario Virgen del Rocío, Seville, Spain. sramon@cica.es
authors.forename: Santiago R
authors.initials: SR
authors.lastname: Leal-Noval
authors.forename: Manuel
authors.initials: M
authors.lastname: Múñoz-Gómez
authors.forename: Francisco
authors.initials: F
authors.lastname: Murillo-Cabezas
mesh_terms: D001793:Blood Preservation; D001930:Brain Injuries / Q000503:physiopathology* / Q000628:therapy; D002545:Brain Ischemia / Q000503:physiopathology* / Q000628:therapy; D017707:Erythrocyte Transfusion / Q000379:methods*; D006454:Hemoglobins / Q000032:analysis*; D006801:Humans; D013345:Subarachnoid Hemorrhage / Q000503:physiopathology* / Q000628:therapy
chemical_list: D006454:Hemoglobins