title: Poor-grade aneurysmal subarachnoid hemorrhage: relationship of cerebral metabolism to outcome.
abstract: OBJECTIVE
  The majority of patients with poor-grade subarachnoid hemorrhage (SAH), that is, World Federation of Neurosurgical Societies (WFNS) Grades IV and V, have high morbidity and mortality rates. The objective of this study was to investigate cerebral metabolism in patients with low- compared with high-grade SAH by using bedside microdialysis and to evaluate whether microdialysis parameters are of prognostic value for outcome in SAH.
  
  
  METHODS
  A prospective investigation was conducted in 149 patients with SAH (mean age 50.9 +/- 12.9 years); these patients were studied for 162 +/- 84 hours (mean +/- standard deviation). Lesions were classified as low-grade SAH (WFNS Grades I-III, 89 patients) and high-grade SAH (WFNS Grade IV or V, 60 patients). After approval by the local ethics committee and consent from the patient or next of kin, a microdialysis catheter was inserted into the vascular territory of the aneurysm after clip placement. The microdialysates were analyzed hourly for extracellular glucose, lactate, lactate/pyruvate (L/P) ratio, glutamate, and glycerol. The 6- and 12-month outcomes according to the Glasgow Outcome Scale and functional disability according to the modified Rankin Scale were assessed. In patients with high-grade SAH, cerebral metabolism was severely deranged compared with those who suffered low-grade SAH, with high levels (p < 0.05) of lactate, a high L/P ratio, high levels of glycerol, and, although not significant, of glutamate. Univariate analysis revealed a relationship among hyperglycemia on admission, Fisher grade, and 12-month outcome (p < 0.005). In a multivariate regression analysis performed in 131 patients, the authors identified four independent predictors of poor outcome at 12 months, in the following order of significance: WFNS grade, patient age, L/P ratio, and glutamate (p < 0.03).
  
  
  CONCLUSIONS
  Microdialysis parameters reflected the severity of SAH. The L/P ratio was the best metabolic independent prognostic marker of 12-month outcome. A better understanding of the causes of deranged cerebral metabolism may allow the discovery of therapeutic options to improve the prognosis, especially in patients with high-grade SAH, in the future.
authors.affiliation: Department of Neurosurgery and Institute of Medical Biometry, Charité Virchow Medical Center, Humboldt University of Berlin, Germany. asita.sarrafzadeh@charite.de
authors.forename: Asita
authors.initials: A
authors.lastname: Sarrafzadeh
authors.forename: Daniel
authors.initials: D
authors.lastname: Haux
authors.forename: Ingeborg
authors.initials: I
authors.lastname: Küchler
authors.forename: Wolfgang R
authors.initials: WR
authors.lastname: Lanksch
authors.forename: Andreas W
authors.initials: AW
authors.lastname: Unterberg
mesh_terms: D001921:Brain / Q000378:metabolism* / Q000601:surgery*; D004185:Disability Evaluation; D005260:Female; D015600:Glasgow Coma Scale; D005947:Glucose / Q000378:metabolism; D018698:Glutamic Acid / Q000378:metabolism; D006801:Humans; D006943:Hyperglycemia / Q000175:diagnosis; D002532:Intracranial Aneurysm / Q000150:complications* / Q000601:surgery*; D019344:Lactic Acid / Q000378:metabolism; D008297:Male; D017551:Microdialysis / Q000379:methods*; D008875:Middle Aged; D019635:Neurosurgical Procedures / Q000379:methods; D019095:Point-of-Care Systems; D011446:Prospective Studies; D019289:Pyruvic Acid / Q000378:metabolism; D013345:Subarachnoid Hemorrhage / Q000175:diagnosis / Q000209:etiology / Q000601:surgery; D016896:Treatment Outcome
chemical_list: D019344:Lactic Acid; D018698:Glutamic Acid; D019289:Pyruvic Acid; D005947:Glucose