title: Neurochemical monitoring using intracerebral microdialysis during systemic haemorrhage.
abstract: BACKGROUND
  Intracerebral microdialysis is a sensitive tool to analyse tissue biochemistry, but the value of this technique to monitor cerebral metabolism during systemic haemorrhage is unknown. The present study was designed to assess changes of intracerebral microdialysis parameters both during systemic haemorrhage and after initiation of therapy.
  
  
  METHODS
  Following approval of the Animal Investigational Committee, 18 healthy pigs underwent a penetrating liver trauma. Following haemodynamic decompensation, all animals received a hypertonic-hyperoncotic solution and either norepinephrine or arginine vasopressin, and bleeding was subsequently controlled. Extracellular cerebral concentrations of glucose (Glu), lactate (La), glycerol (Gly), and the lactate/pyruvate ratio (La/Py ratio) were assessed by microdialysis. Cerebral venous protein S-100B was determined. Haemodynamic data, blood gases, S-100B, and microdialysis variables were determined at baseline, at haemodynamic decompensation, and repeated after drug administration.
  
  
  RESULTS
  Microdialysis measurements showed an increase of La, Gly, and La/Py ratio at BL Th compared to BL (mean +/- SEM; La 2.4 +/- 0.2 vs. 1.4 +/- 0.2 mmol x l(-1), p < 0.01; Gly 37 +/- 7 vs. 27 +/- 6 micromol x l(-1), n.s.; La/Py ratio 50 +/- 8 vs. 30 +/- 4, p < 0.01), followed by a further increase during the therapy phase (La 3.4 +/- 0.3 mmol x l(-1); Gly 69 +/- 10 micromol x l(-1); La/Py ratio 58 +/- 8; p < 0.001, respectively). Cerebral venous protein S-100B increased at decompensation and after therapy, but decreased close to baseline values after 90 min of therapy.
  
  
  CONCLUSIONS
  In this model of systemic haemorrhage, changes of cerebral energy metabolism detected by intracerebral microdialysis indicated anaerobic glycolysis and degradation of cellular membranes throughout the study period.
authors.affiliation: Department of Anaesthesiology and Intensive Care Medicine, University Hospital Schleswig-Holstein, Campus Kiel, Germany. meybohm@anaesthesie.uni-kiel.de
authors.forename: P
authors.initials: P
authors.lastname: Meybohm
authors.forename: E
authors.initials: E
authors.lastname: Cavus
authors.forename: B
authors.initials: B
authors.lastname: Bein
authors.forename: M
authors.initials: M
authors.lastname: Steinfath
authors.forename: B
authors.initials: B
authors.lastname: Weber
authors.forename: J
authors.initials: J
authors.lastname: Scholz
authors.forename: V
authors.initials: V
authors.lastname: Doerges
mesh_terms: D000818:Animals; D001921:Brain / Q000378:metabolism / Q000503:physiopathology*; D001923:Brain Chemistry / Q000502:physiology*; D002560:Cerebrovascular Circulation / Q000502:physiology; D004195:Disease Models, Animal; D004734:Energy Metabolism / Q000502:physiology*; D045604:Extracellular Fluid / Q000737:chemistry / Q000378:metabolism; D005260:Female; D005947:Glucose / Q000378:metabolism; D005990:Glycerol / Q000378:metabolism; D006019:Glycolysis / Q000502:physiology; D006470:Hemorrhage / Q000150:complications / Q000503:physiopathology*; D020925:Hypoxia-Ischemia, Brain / Q000175:diagnosis / Q000209:etiology / Q000503:physiopathology*; D019344:Lactic Acid / Q000378:metabolism; D008297:Male; D008565:Membrane Proteins / Q000032:analysis / Q000378:metabolism; D017551:Microdialysis / Q000379:methods* / Q000592:standards; D008991:Monitoring, Physiologic / Q000379:methods / Q000592:standards; D009414:Nerve Growth Factors / Q000032:analysis / Q000097:blood; D064568:S100 Calcium Binding Protein beta Subunit; D009418:S100 Proteins / Q000032:analysis / Q000097:blood; D012769:Shock / Q000150:complications / Q000503:physiopathology; D034421:Sus scrofa
chemical_list: D008565:Membrane Proteins; D009414:Nerve Growth Factors; D064568:S100 Calcium Binding Protein beta Subunit; D009418:S100 Proteins; D019344:Lactic Acid; D005947:Glucose; D005990:Glycerol