title: Dual microdialysis probe monitoring for patients with traumatic brain injury.
abstract: BACKGROUND
  In vivo microdialysis can be used to examine the focal metabolism by measuring the extracellular concentration of amino acids and other biochemicals in the focal brain tissue in which the probe is placed. We report two patients with traumatic brain injury who underwent placement of dual microdialysis probes.
  
  
  METHODS
  One probe was placed in the penumbra zone and another in a region remote to the injury. Multiple measurements of several biochemical's were made.
  
  
  RESULTS
  In the first case, a 54-year-old man with right acute subdural hematoma and right fronto-temporal contusion was monitored. Quantitative analysis of in vivo microdialysis was performed. While the extracellular concentration of lactate and glycerol were higher in the penumbra zone than in the region remote to the injury, glutamate remained lower in the penumbra zone than in the remote region. In the second case, dual microdialysis probes were placed in a 56-year-old woman with left acute subdural hematoma and left fronto-temporal lobe contusion. Also in this case, the extracellular glutamate remained lower in the penumbra zone than in the remote region.
  
  
  CONCLUSIONS
  The reason why the extracellular glutamate value remained lower in the penumbra zone than in the remote region is unclear. The position of each microdialysis probe was ensured by CT scan after the operation. It is important to be aware of the limitations of performing microdialysis in brain injured patients with a single probe.
authors.affiliation: Department of Neurosurgery, Yamaguchi University School of Medicine, 1-1-1 Minami-kogushi, Ube, Yamaguchi 755-8505, Japan. hiroyasu@yamaguchi-u.ac.jp
authors.forename: Hiroyasu
authors.initials: H
authors.lastname: Koizumi
authors.forename: Hirosuke
authors.initials: H
authors.lastname: Fujisawa
authors.forename: Sudahiro
authors.initials: S
authors.lastname: Nomura
authors.forename: Shoichi
authors.initials: S
authors.lastname: Kato
authors.forename: Koji
authors.initials: K
authors.lastname: Kajiwara
authors.forename: Masami
authors.initials: M
authors.lastname: Fujii
authors.forename: Michiyasu
authors.initials: M
authors.lastname: Suzuki
mesh_terms: D001930:Brain Injuries / Q000000981:diagnostic imaging / Q000378:metabolism* / Q000473:pathology; D004563:Electrochemistry / Q000379:methods; D005110:Extracellular Space / Q000378:metabolism; D005260:Female; D018698:Glutamic Acid / Q000378:metabolism; D006801:Humans; D019344:Lactic Acid / Q000378:metabolism; D008297:Male; D017551:Microdialysis / Q000379:methods*; D008875:Middle Aged; D008991:Monitoring, Physiologic; D014057:Tomography, X-Ray Computed / Q000379:methods
chemical_list: D019344:Lactic Acid; D018698:Glutamic Acid