Cerebral Microdialysis: A Metabolic Sensor Inside the Closed Box

Abstract

The cranial vault was regarded by Monro-Kellie doctrine as a closed box containing the three components namely: brain, blood and cerebrospinal fluid. The brain is orders of magnitude, more complex than the heart and other vital organs yet its function has been more difficult to monitor being contained in a rigid closed box. Following an acute neurological catastrophe such as traumatic brain injury (TBI) or stroke, damage to the brain can occur at the time of the initial event. This damage is termed “primary brain injury”. Regardless of the interventions performed to limit this primary injury, much of the primary damage may be irreversible. However, this primary brain injury initi¬ates a cascade of biochemical events that are potentially reversible. This process, termed “secondary brain injury”, includes structural and chemical derangement as well as alterations in cerebral blood flow and oxygen delivery. Management of secondary brain injury is of fundamental importance to the treatment of patients with TBI, ischemic and hemorrhagic stroke, and global cerebral ischemia [1].