Real-time multi-site multi-parametric monitoring of rat brain subjected to traumatic brain injury

Introduction: Traumatic brain injury (TBI) is one of the major causes of death in the world, with at least ten million serious traumatic brain injuries occurring annually; nevertheless, the pathophysiologic events taking place immediately after the injury are not yet fully known. Objective: To study the effects of TBI on brain hemodynamic, metabolic and ionic homeostasis using the multi-parametric monitoring system. This system enables real-time monitoring of cerebral blood flow (CBF), mitochondrial NADH redox state, extracellular levels of K⁺, H⁺, DC potential, ECoG and ICP. Methods: In order to find the best brain location for the monitoring device in relation to the fluid percussion injury site, we used the multi-site multi-parametric monitoring system²⁵. Two groups of rats were connected to four monitoring probes at four different locations near the injury site, two in each hemisphere. We monitored CBF, NADH redox state, tissue reflectance and DC steady potential in each of the four sites. Results: Under anoxia, the initial CBF decrease was followed by an increase, NADH level increased, the reflectance decreased and dc potential showed a biphasic response, in all 4 locations. However, following fluid percussion injury, there was a significant variability in the responses in each of the 4 monitored locations. Conclusion: The advantage of the multi-parametric-monitoring approach for enhanced understanding of the injured brain was indicated. Moreover, we showed that contralateral monitoring of the injured brain gives good indication for the events taking place following fluid percussion brain injury.