title: The Effect of Packed Red Blood Cell Transfusion on Cerebral Oxygenation and Metabolism After Subarachnoid Hemorrhage.
abstract: BACKGROUND
  Anemia adversely affects cerebral oxygenation and metabolism after subarachnoid hemorrhage (SAH) and is also associated with poor outcome. There is limited evidence to support the use of packed red blood cell (PRBC) transfusion to optimize brain homeostasis after SAH. The aim of this study was to investigate the effect of transfusion on cerebral oxygenation and metabolism in patients with SAH.
  
  
  METHODS
  This was a prospective observational study in a neurological intensive care unit of a university hospital. Nineteen transfusions were studied in 15 consecutive patients with SAH that underwent multimodality monitoring (intracranial pressure, brain tissue oxygen, and cerebral microdialysis). Data were collected at baseline and for 12 h after transfusion. The relationship between hemoglobin (Hb) change and lactate/pyruvate ratio (LPR) orbrain tissue oxygen (PbtO2) was tested using univariate and multivariable analyses.
  
  
  RESULTS
  PRBC transfusion was administered on the median post-bleed day 8. The average Hb concentration at baseline was 8.1 g/dL and increased by 2.2 g/dL after transfusion. PbtO2 increased between hours 2 and 4 post-transfusion and this increase was maintained until hour 10. LPR did not change significantly during the 12-h monitoring period. After adjusting for SpO2, cerebral perfusion pressure, and LPR, the change in Hb concentration was independently and positively associated with a change in PbtO2 (adjusted b estimate = 1.39 [95% confidence interval 0.09-2.69]; P = 0.04). No relationship between the change in Hb concentration and LPR was found.
  
  
  CONCLUSIONS
  PRBC transfusion resulted in PbtO2 improvement without a clear effect on cerebral metabolism prior to SAH.
authors.affiliation: Neurological Intensive Care Unit, Brain Institute Paulo Niemeyer, Rio de Janeiro, Brazil. kurtzpedro@mac.com.
authors.forename: Pedro
authors.initials: P
authors.lastname: Kurtz
authors.affiliation: Neurological Intensive Care Unit, Department of Neurology, Medical University of Innsbruck, Innsbruck, Austria. raimund.helbok@uki.at.
authors.forename: Raimund
authors.initials: R
authors.lastname: Helbok
authors.affiliation: Division of Critical Care Neurology and Comprehensive Epilepsy Center, College of Physicians and Surgeons, Neurological Institute, Columbia University, New York, NY, USA. jc1439@columbia.edu.
authors.forename: Jan
authors.initials: J
authors.lastname: Claassen
authors.affiliation: Division of Critical Care Neurology, Neurological Institute, Columbia University College of Physicians and Surgeons, New York, NY, USA. mjs2134@columbia.edu.
authors.forename: J Michael
authors.initials: JM
authors.lastname: Schmidt
authors.affiliation: Division of Critical Care Neurology, Neurological Institute, Columbia University College of Physicians and Surgeons, New York, NY, USA. luisfernandezmd@gmail.com.
authors.forename: Luis
authors.initials: L
authors.lastname: Fernandez
authors.affiliation: Department of Neurological Surgery, Columbia University College of Physicians and Surgeons, New York, NY, USA. rms2130@columbia.edu.
authors.forename: R Morgan
authors.initials: RM
authors.lastname: Stuart
authors.affiliation: Department of Neurological Surgery, Columbia University College of Physicians and Surgeons, New York, NY, USA. SConnolly@neuro.columbia.edu.
authors.forename: E Sander
authors.initials: ES
authors.lastname: Connolly
authors.affiliation: Departments of Neurology and Neurosurgery, The University of Texas Medical School at Houston, Houston, TX, USA. Kiwon.Lee@uth.tmc.edu.
authors.forename: Kiwon
authors.initials: K
authors.lastname: Lee
authors.affiliation: Institute of Critical Care Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA. stephan.mayer@mountsinai.org.
authors.forename: Stephan A
authors.initials: SA
authors.lastname: Mayer
authors.affiliation: Department of Neurology, University of Maryland School of Medicine, Baltimore, MA, USA. nbadjatia@som.umaryland.edu.
authors.forename: Neeraj
authors.initials: N
authors.lastname: Badjatia
mesh_terms: D000328:Adult; D000368:Aged; D001921:Brain / Q000378:metabolism*; D017707:Erythrocyte Transfusion / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000378:metabolism*; D010101:Oxygen Consumption / Q000502:physiology; D013345:Subarachnoid Hemorrhage / Q000378:metabolism* / Q000628:therapy*; D016896:Treatment Outcome
chemical_list: D010100:Oxygen
keywords: Brain oxygen; Cerebral metabolism; Stroke; Subarachnoid hemorrhage