TY - JOUR
T1 - Concurrent monitoring of cerebral electrophysiology and metabolism after traumatic brain injury
T2 - An experimental and clinical study
AU - Alves, Oscar L.
AU - Bullock, Ross
AU - Clausen, Tobias
AU - Reinert, Michael
AU - Reeves, Thomas M.
N1 - Copyright:
Copyright 2008 Elsevier B.V., All rights reserved.
PY - 2005/7
Y1 - 2005/7
N2 - Multiparameter cerebral monitoring has been widely applied in traumatic brain injury to study posttraumatic pathophysiology and to manage head-injured patients (e.g., combining O2 and pH sensors with cerebral microdialysis). Because a comprehensive approach towards understanding injury processes will also require functional measures, we have added electrophysiology to these monitoring modalities by attaching a recording electrode to the microdialysis probe. These dual-function (microdialysis/electrophysiology) probes were placed in rats following experimental fluid percussion brain injuries, and in a series of severely head-injured human patients. Electrical activity (cell firing, EEG) was monitored concurrently with microdialysis sampling of extracellular glutamate, glucose and lactate. Electrophysiological parameters (firing rate, serial correlation, field potential occurrences) were analyzed offline and compared to dialysate concentrations. In rats, these probes demonstrated an injury-induced suppression of neuronal firing (from a control level of 2.87 to 0.41 spikes/sec postinjury), which was associated with increases in extracellular glutamate and lactate, and decreases in glucose levels. When placed in human patients, the probes detected sparse and slowly firing cells (mean = 0.21 spike/sec), with most units (70%) exhibiting a lack of serial correlation in the spike train. In some patients, spontaneous field potentials were observed, suggesting synchronously firing neuronal populations. In both the experimental and clinical application, the addition of the recording electrode did not appreciably affect the performance of the microdialysis probe. The results suggest that this technique provides a functional monitoring capability which cannot be obtained when electrophysiology is measured with surface or epidural EEG alone.
AB - Multiparameter cerebral monitoring has been widely applied in traumatic brain injury to study posttraumatic pathophysiology and to manage head-injured patients (e.g., combining O2 and pH sensors with cerebral microdialysis). Because a comprehensive approach towards understanding injury processes will also require functional measures, we have added electrophysiology to these monitoring modalities by attaching a recording electrode to the microdialysis probe. These dual-function (microdialysis/electrophysiology) probes were placed in rats following experimental fluid percussion brain injuries, and in a series of severely head-injured human patients. Electrical activity (cell firing, EEG) was monitored concurrently with microdialysis sampling of extracellular glutamate, glucose and lactate. Electrophysiological parameters (firing rate, serial correlation, field potential occurrences) were analyzed offline and compared to dialysate concentrations. In rats, these probes demonstrated an injury-induced suppression of neuronal firing (from a control level of 2.87 to 0.41 spikes/sec postinjury), which was associated with increases in extracellular glutamate and lactate, and decreases in glucose levels. When placed in human patients, the probes detected sparse and slowly firing cells (mean = 0.21 spike/sec), with most units (70%) exhibiting a lack of serial correlation in the spike train. In some patients, spontaneous field potentials were observed, suggesting synchronously firing neuronal populations. In both the experimental and clinical application, the addition of the recording electrode did not appreciably affect the performance of the microdialysis probe. The results suggest that this technique provides a functional monitoring capability which cannot be obtained when electrophysiology is measured with surface or epidural EEG alone.
KW - Cerebral monitoring
KW - Electrophysiology
KW - Extracellular glutamate
KW - Metabolic dysfunction
KW - Microdialysis
KW - Traumatic brain injury
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U2 - 10.1089/neu.2005.22.733
DO - 10.1089/neu.2005.22.733
M3 - Article
C2 - 16004577
AN - SCOPUS:22244454035
VL - 22
SP - 733
EP - 749
JO - Journal of Neurotrauma
JF - Journal of Neurotrauma
SN - 0897-7151
IS - 7
ER -