Cerebral Microdialysis in Neurocritical Care

A major goal in neurocritical care is to monitor for and prevent secondary brain injuries. However, injuries occurring at the cellular and molecular levels evade detection by conventional hemodynamic monitoring and the neurological exam. Cerebral microdialysis (CMD) is an invasive means of providing nearly continuous measurements of cerebral metabolism and is a promising tool that can detect signs of cellular distress before systemic manifestations of intracranial catastrophe.

In this review, we describe the technique of CMD and the common biomarkers used to monitor cerebral energy metabolism. We examine the published evidence on how CMD data reflect secondary injuries and improve understanding of the pathophysiology of traumatic brain injury (TBI) and aneurysmal subarachnoid hemorrhage. We also discuss some of the caveats of the technique, including how CMD probe position affect the sensitivity of capturing energy failures, and how abnormal levels of cerebral glucose and lactate can reflect different states of cerebral energy metabolism. In order to best incorporate cerebral metabolic monitoring into the management of neurocritical care patients, neurointensivists must be familiar with the nuances in the limitations as well as the interpretations of data obtained from cerebral microdialysis.