Cerebrospinal fluid and brain extracellular fluid in severe brain trauma.

Traumatic brain injury is a major cause of morbidity and mortality worldwide. Pathophysiologic mechanisms of secondary brain injury are complex and still not fully understood. Cerebrospinal fluid deserves attention to detect infectious complications and to identify biomarkers of disease severity and impending secondary brain injury. As an adjunct, cerebral microdialysis (CMD) allows online measurements of biomarkers derived directly from brain extracellular fluid. We critically review relevant literature related to infectious complications detectable in the cerebrospinal fluid in trauma patients. We then address the current role of CMD in clinical practice in the identification and prediction of secondary brain injury after severe trauma. Moreover we discuss the role of CMD-derived biomarkers in prognostication. Finally we challenge common treatment strategies and provide novel treatment concepts using brain-derived biomarkers as endpoints. We suggest a personalized treatment strategy for individual patients with severe traumatic brain injury.