Abstract
Object Many studies have reported that extracellular chemistry is related to the outcome
of patients with traumatic brain injury (TBI). No study has reported that extracellular
chemistry predicts outcome in less than 3 days. Moreover, in other studies, both focal
brain and diffuse brain injuries have been often discussed. The authors focused on
the relationship between extracellular chemistry in a shorter period and the outcome
of patients with focal brain injury.
Methods By using intracerebral microdialysis monitoring, extracellular fluid concentrations
of glucose, lactate, glycerol, glutamate, lactate/pyruvate (L/P), and lactate/glucose
(L/G) were determined in 30 patients with severe TBI for initial 24 hours. The results
were analyzed between favorable and unfavorable, and between survival and mortality.
Results The medians of glycerol and L/P in the favorable group were significantly lower than
those in the unfavorable group (124 µmol/L vs. 808 µmol/L, p = 0.002; 31 vs. 48, p = 0.021, respectively). All parameters apart from glutamate differed significantly
between the survival and mortality groups (glucose, 25 mmol/L vs. 77 mmol/L, p = 0.035; lactate, 38 mmol/L vs. 73 mmol/L, p = 0.018; glycerol, 168 µmol/L vs. 1462 µmol/L, p = 0.002; glutamate, 14 µmol/L vs. 95 µmol/L, p = 0.019; L/P, 32 vs. 124, p < 0.001; L/G, 1.46 vs. 4.52, p = 0.004).
Conclusion Cerebral extracellular glycerol and L/P was the most reliable predictor of outcomes
in patients with focal brain injury and can discriminate between favorable and unfavorable
outcomes for the first 24 hours, using the threshold of 200 and 40, respectively.
Keywords
microdialysis - traumatic brain injury - cerebral extracellular chemistry - lactate/pyruvate
- glycerol
