title: Are primary supratentorial intracerebral hemorrhages surrounded by a biochemical penumbra? A microdialysis study.
abstract: OBJECTIVE
  Opinions vary regarding the indications for surgical evacuation of spontaneous intracerebral hemorrhages (ICH) and whether or not penumbra zones surround them.
  
  
  METHODS
  We performed intracerebral microdialysis (mean duration, 3.5 d) after surgical evacuation of ICH in 22 patients. Probes were placed in the parenchyma within 1 to 2 cm of the evacuated hematoma; a postoperative computed tomographic scanning verified their positions. The catheters were perfused with an artificial cerebrospinal fluid solution at 0.3 microl/min. Biochemical variables (glucose, pyruvate, lactate, glutamate, and glycerol) were analyzed and displayed at the bedside. The levels obtained were compared with previous data from normal human brains and the pericontusional penumbra zones of patients with severe traumatic brain lesions.
  
  
  RESULTS
  During 1 to 12 hours after surgery, interstitial levels of glucose (median level, 1.3 mmol/L; interquartile range, 0.6-2.2 mmol/L) were within normal variations, whereas the levels of lactate (median level, 6.4 mmol/L; interquartile range, 3.9-9.0 mmol/L), glutamate (median level, 14 micromol/L; interquartile range, 5-370 micromol/L), and glycerol (median level, 190 micromol/L; interquartile range, 74-380 micromol/L), as well as the lactate/pyruvate ratio (median ratio, 35; interquartile range, 23-50) were increased. A gradual normalization of the lactate/pyruvate ratio and glycerol level was observed within 48 hours.
  
  
  CONCLUSIONS
  The area close to an evacuated ICH exhibits a biochemical pattern similar to that of the biochemical penumbra zone surrounding focal traumatic brain contusions. The presence of a penumbra zone around large ICH may be of importance for making surgical decisions.
authors.affiliation: Department of Neurosurgery, Lund University Hospital, Lund, Sweden. ola.nilsson@med.lu.se
authors.forename: Ola G
authors.initials: OG
authors.lastname: Nilsson
authors.forename: Angelo
authors.initials: A
authors.lastname: Polito
authors.forename: Hans
authors.initials: H
authors.lastname: Säveland
authors.forename: Urban
authors.initials: U
authors.lastname: Ungerstedt
authors.forename: Carl-Henrik
authors.initials: CH
authors.lastname: Nordström
mesh_terms: D000328:Adult; D000368:Aged; D002543:Cerebral Hemorrhage / Q000378:metabolism* / Q000601:surgery; D018846:Excitatory Amino Acids / Q000378:metabolism*; D005260:Female; D005947:Glucose / Q000378:metabolism; D006801:Humans; D019344:Lactic Acid / Q000378:metabolism; D008297:Male; D017551:Microdialysis / Q000379:methods*; D008875:Middle Aged; D011446:Prospective Studies
chemical_list: D018846:Excitatory Amino Acids; D019344:Lactic Acid; D005947:Glucose