Cerebral energy metabolism during transient hyperglycemia in patients with severe brain trauma.
OBJECTIVE
To study whether transient hyperglycemia adversely affects cerebral energy metabolism in patients with severe traumatic brain lesions.


METHODS
Prospective, nonrandomized study in the neurosurgical intensive care unit of a university hospital.


METHODS
108 patients treated for severe traumatic brain lesions.


METHODS
All patients were treated according to neurosurgical intensive care routine including monitoring of intracranial pressure. One microdialysis catheter was inserted via a burr hole frontally to that used for the intraventricular catheter ("better" position). In patients with focal lesions one or more catheters were inserted into cerebral cortex surrounding an evacuated focal contusion or underlying an evacuated hematoma ("worse" position). Perfusion rate was 0.3 micro l/min and samples were taken every 30 or 60 min. The levels of glucose, pyruvate, lactate, glutamate, and glycerol were analyzed and displayed bedside.


RESULTS
There were 18 episodes of moderate (12-15 mmol/l) and 6 episodes of pronounced (>15 mmol/l) hyperglycemia. Moderate hyperglycemia did not change intracerebral levels of lactate, pyruvate, glutamate, glycerol, or lactate/pyruvate ratio. Lactate concentrations increased during pronounced hyperglycemia. Pronounced cerebral lactic acidosis and a moderate increase in interstitial glycerol concentration indicating cell membrane degradation was observed in a single patient with pronounced, long-lasting hyperglycemia.


CONCLUSIONS
Cerebral energy metabolism was affected by transient hyperglycemia only at blood glucose concentration above 15 mmol/l as shown by a moderate increase in interstitial lactate level.
Diaz-Parejo
Pedro
P
Department of Intensive Care, University Hospital Virgen del Rocio, Seville, Spain.
Ståhl
Nils
N
Xu
Wangbin
W
Reinstrup
Peter
P
Ungerstedt
Urban
U
Nordström
Carl-Henrik
CH
D001786:Blood Glucose / Q000378:metabolism; D001930:Brain Injuries / Q000378:metabolism*; D002560:Cerebrovascular Circulation; D004734:Energy Metabolism; D005260:Female; D018698:Glutamic Acid / Q000097:blood; D005990:Glycerol / Q000097:blood; D006801:Humans; D006943:Hyperglycemia / Q000378:metabolism*; D007427:Intracranial Pressure; D007773:Lactates / Q000097:blood; D008297:Male; D017551:Microdialysis; D011446:Prospective Studies; D019289:Pyruvic Acid / Q000097:blood
D001786:Blood Glucose; D007773:Lactates; D018698:Glutamic Acid; D019289:Pyruvic Acid; D005990:Glycerol