Relationship between excitatory amino acid release and outcome after severe human head injury.
In previous studies, Katayama and our group have documented a massive increase in excitatory amino acid release following traumatic brain injury, in both rat fluid percussion, and humans [2,5]. To test the hypothesis that the magnitude of this "Excitotoxic Surge" plays a significant role in determining 6-month patient outcome. We have studied 83 consecutive severely head injured patients at the Medical College of Virginia for inclusion into this study. A microdialysis probe was placed within the cortex to continuously measure dialysate excitatory amino acids (Glutamate and Aspartate), along with several other analytes for approximately 5 days after injury. ICP, CPP, and MABP measurements were also time linked with each analyte measurement to create a neurochemical, clinical, and physiological "profile" for each patient. Outcome was determined by follow up using the Glasgow 6-Month outcome scale. A very strong correlation existed between the release of the EAA's glutamate and aspartate after TBI (p < 0.0001). Patients with significantly elevated mean glutamate values for the entire monitoring period were most likely to exhibit elevated levels of ICP. The magnitude of glutamate released significantly correlates with 6-month patient outcome (p = 0.0234). When patients were subdivided by the CT diagnosis of lesion type, we found that those patients with contusions displayed the highest overall of EAA's.
Koura
S S
SS
Division of Neurosurgery, Medical College of Virginia, Virginia Commonwealth University, Richmond, USA.
Doppenberg
E M
EM
Marmarou
A
A
Choi
S
S
Young
H F
HF
Bullock
R
R
D000818:Animals; D001224:Aspartic Acid / Q000378:metabolism; D001925:Brain Damage, Chronic / Q000175:diagnosis* / Q000503:physiopathology; D001930:Brain Injuries / Q000503:physiopathology*; D002540:Cerebral Cortex / Q000293:injuries / Q000503:physiopathology; D018846:Excitatory Amino Acids / Q000378:metabolism*; D015600:Glasgow Coma Scale; D018698:Glutamic Acid / Q000378:metabolism; D006801:Humans; D017551:Microdialysis; D017063:Outcome Assessment, Health Care; D011379:Prognosis; D051381:Rats
D018846:Excitatory Amino Acids; D001224:Aspartic Acid; D018698:Glutamic Acid