title: Cerebral perfusion pressure thresholds for brain tissue hypoxia and metabolic crisis after poor-grade subarachnoid hemorrhage.
abstract: OBJECTIVE
  To identify a minimally acceptable cerebral perfusion pressure threshold above which the risks of brain tissue hypoxia (BTH) and oxidative metabolic crisis are reduced for patients with subarachnoid hemorrhage (SAH).
  
  
  METHODS
  We studied 30 poor-grade SAH patients who underwent brain multimodality monitoring (3042 hours). Physiological measures were averaged over 60 minutes for each collected microdialysis sample. Metabolic crisis was defined as a lactate/pyruvate ratio>40 with a brain glucose concentration≤0.7 mmol/L. BTH was defined as PbtO2<20 mm Hg. Outcome was assessed at 3 months with the Modified Rankin Scale.
  
  
  RESULTS
  Multivariable analyses adjusting for admission Hunt-Hess grade, intraventricular hemorrhage, systemic glucose, and end-tidal CO2 revealed that cerebral perfusion pressure≤70 mm Hg was significantly associated with an increased risk of BTH (OR, 2.0; 95% CI, 1.2-3.3; P=0.007) and metabolic crisis (OR, 2.1; 95% CI, 1.2-3.7; P=0.007). Death or severe disability at 3 months was significantly associated with metabolic crisis (OR, 5.4; 95% CI, 1.8-16; P=0.002) and BTH (OR, 5.1; 95% CI, 1.2-23; P=0.03) after adjusting for admission Hunt-Hess grade.
  
  
  CONCLUSIONS
  Metabolic crisis and BTH are associated with mortality and poor functional recovery after SAH. Cerebral perfusion pressure levels<70 mm Hg was associated with metabolic crisis and BTH, and may increase the risk of secondary brain injury in poor-grade SAH patients.
authors: Neurological Intensive Care Unit, Department of Neurology, Columbia University Medical Center, and Milstein Hospital, 177 Fort Washington, 8-300, New York, NY 10032, USA. mjs2134@columbia.edu
authors: J Michael
authors: JM
authors: Schmidt
authors: Sang-Bae
authors: SB
authors: Ko
authors: Raimund
authors: R
authors: Helbok
authors: Pedro
authors: P
authors: Kurtz
authors: R Morgan
authors: RM
authors: Stuart
authors: Mary
authors: M
authors: Presciutti
authors: Luis
authors: L
authors: Fernandez
authors: Kiwon
authors: K
authors: Lee
authors: Neeraj
authors: N
authors: Badjatia
authors: E Sander
authors: ES
authors: Connolly
authors: Jan
authors: J
authors: Claassen
authors: Stephan A
authors: SA
authors: Mayer
mesh_terms: D000328:Adult; D004734:Energy Metabolism / Q000502:physiology; D005260:Female; D005947:Glucose / Q000378:metabolism; D006801:Humans; D002534:Hypoxia, Brain / Q000453:epidemiology* / Q000503:physiopathology*; D007773:Lactates / Q000378:metabolism; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D018384:Oxidative Stress / Q000502:physiology*; D010477:Perfusion; D011773:Pyruvates / Q000378:metabolism; D012189:Retrospective Studies; D012307:Risk Factors; D013345:Subarachnoid Hemorrhage / Q000378:metabolism* / Q000503:physiopathology*
chemical_list: D007773:Lactates; D011773:Pyruvates; D005947:Glucose