Cerebral microdialysis is now widely used as a bedside monitor of brain tissue biochemistry to identify cerebral hypoxia/ischaemia and assess cellular bioenergetics after brain injury. This chapter reviews the principles of cerebral microdialysis and identifies its role in detecting derangements of cerebral metabolism after brain injury. Microdialysis is used for a variety of clinical indications, including tissue monitoring in myocutaneous flap surgery, transplant surgery and bowel anastamoses. The concentration of substances in the dialysate will depend on the balance between substrate delivery to, and uptake from, the brain extracellular fluid (ECF) but also on several other factors. The pathophysiology of acute brain injury is complex, but two factors are of crucial importance: reduction of substrate delivery below critical thresholds, and the inability of brain cells to utilize delivered oxygen and glucose because of failing cellular metabolism.

This chapter reviews the history, evolution and organization of neurointensive care units. It emphasizes the key role that neurointensive care teams play in delivering improved outcomes for patients. Neurointensive care has evolved from its original single-system focus on the central nervous system (CNS) to a multisystem speciality providing all aspects of a patient's care. Despite the widespread availability and relative simplicity of many neuromonitoring techniques, there is considerable variation in their placement and in the application of monitoring-guided therapeutic strategies. The overall goals of neurointensive care are to resuscitate and support the acutely ill patient, minimize secondary neurological injury, and prevent or treat systemic (non-neurological) complications. Protocol-guided treatment improves clinical outcome in all areas of medicine and is effective in reducing mortality and improving outcome after brain injury. Expertise in neurointensive care involves procedural skills, proficiency with standard (systemic) monitoring and management, as well as specialized neuromonitoring techniques and interventions.