Detection of critical oligemia in patients with traumatic intracerebral hemorrhage using continuous quantitative electroencephalography and cerebral microdialysis
Introduction: Serial changes in cerebral blood flow after intracerebral hemorrhage may influence tissue viability in regions surrounding the hematoma. Non invasive monitoring may assist titration of systolic blood pressure. Purpose: To determine if continuous quantitative electroencephalography percent alpha variability(EEGPAV)can discriminate areas of critically reduced cerebral blood flow (CBF). Methods:Ten patients with traumatic intracerebral hemorrhage underwent combined monitoring of cerebral microdialysis, EEGPAV, and intermittent xenon-computerized tomograhpy to determine if EEGPAV monitoring could determine and monitor cellular distress in the context of oligemia. Critical oligemia was defined as CBF < 25. Time and regional matched samples of EEG, microdialysis and CBF were used to correlate across modalities. Regions adjacent to the hematoma only were studied. Results:Six patients had regional CBF < 25 and 4 > 30 cc/100gm/min. In the low CBF group, the mean regional EEGPAV was 0.11 ± 0.4 compared to 0.22 ± 0.3 in the high-normal CBF group(p < 0.01). The low CBF group had lower extracellular levels of glucose (0.33±0.27) compared to the high-normal CBF group (1.9±1.0) (p < 0.001). Extracellular glutamate levels were higher in the low CBF group (14.5 ±23 uM) compared to the high-normal CBF group (1.34±0.8) (p < 0.001). Lactate and glycerol levels were not statistically different between groups (p < 0.8) Conclusion: EEGPAV can discriminate brain regions that have critical oligemia and neurochemichal evidence of cellular distress.