title: Differential influence of arterial blood glucose on cerebral metabolism following severe traumatic brain injury.
abstract: BACKGROUND
  Maintaining arterial blood glucose within tight limits is beneficial in critically ill patients. Upper and lower limits of detrimental blood glucose levels must be determined.
  
  
  METHODS
  In 69 patients with severe traumatic brain injury (TBI), cerebral metabolism was monitored by assessing changes in arterial and jugular venous blood at normocarbia (partial arterial pressure of carbon dioxide (paCO2) 4.4 to 5.6 kPa), normoxia (partial arterial pressure of oxygen (paO2) 9 to 20 kPa), stable haematocrit (27 to 36%), brain temperature 35 to 38 degrees C, and cerebral perfusion pressure (CPP) 70 to 90 mmHg. This resulted in a total of 43,896 values for glucose uptake, lactate release, oxygen extraction ratio (OER), carbon dioxide (CO2) and bicarbonate (HCO3) production, jugular venous oxygen saturation (SjvO2), oxygen-glucose index (OGI), lactate-glucose index (LGI) and lactate-oxygen index (LOI). Arterial blood glucose concentration-dependent influence was determined retrospectively by assessing changes in these parameters within pre-defined blood glucose clusters, ranging from less than 4 to more than 9 mmol/l.
  
  
  RESULTS
  Arterial blood glucose significantly influenced signs of cerebral metabolism reflected by increased cerebral glucose uptake, decreased cerebral lactate production, reduced oxygen consumption, negative LGI and decreased cerebral CO2/HCO3 production at arterial blood glucose levels above 6 to 7 mmol/l compared with lower arterial blood glucose concentrations. At blood glucose levels more than 8 mmol/l signs of increased anaerobic glycolysis (OGI less than 6) supervened.
  
  
  CONCLUSIONS
  Maintaining arterial blood glucose levels between 6 and 8 mmol/l appears superior compared with lower and higher blood glucose concentrations in terms of stabilised cerebral metabolism. It appears that arterial blood glucose values below 6 and above 8 mmol/l should be avoided. Prospective analysis is required to determine the optimal arterial blood glucose target in patients suffering from severe TBI.
authors.affiliation: Surgical Intensive Care Medicine, University Hospital Zuerich, Zuerich, Switzerland. monika.holbein@access.unizh.ch
authors.forename: Monika
authors.initials: M
authors.lastname: Holbein
authors.forename: Markus
authors.initials: M
authors.lastname: Béchir
authors.forename: Silke
authors.initials: S
authors.lastname: Ludwig
authors.forename: Jutta
authors.initials: J
authors.lastname: Sommerfeld
authors.forename: Silvia R
authors.initials: SR
authors.lastname: Cottini
authors.forename: Marius
authors.initials: M
authors.lastname: Keel
authors.forename: Reto
authors.initials: R
authors.lastname: Stocker
authors.forename: John F
authors.initials: JF
authors.lastname: Stover
mesh_terms: D000328:Adult; D000368:Aged; D001158:Arteries / Q000378:metabolism*; D001784:Blood Gas Analysis / Q000379:methods; D001786:Blood Glucose / Q000378:metabolism*; D001921:Brain / Q000378:metabolism*; D001930:Brain Injuries / Q000097:blood*; D002560:Cerebrovascular Circulation / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D053858:Metabolic Networks and Pathways / Q000502:physiology; D008875:Middle Aged; D010101:Oxygen Consumption / Q000502:physiology; D012189:Retrospective Studies
chemical_list: D001786:Blood Glucose