Objective: To review the current data on clinical bedside use of cerebral microdialysis.
Data source: Search through Medline database of articles in French and English (keywords: microdialysis, cerebral ischaemia, head trauma, subarachnoid haemorrhage, clinical study).
Study selection: All clinical articles published between 1995 and 2005, including original papers and some case reports.
Data synthesis: Microdialysis after occlusive stroke has shown elevated levels of glutamate and lactate. When space-occupying oedema develops, biochemistry abnormalities occur first, before ICP increases. Bedside microdialysis appears to be a sensitive and earlier indicator of space occupying oedema. Most Accurate markers to monitor ischaemia induced by vasospasm are glutamate and lactate/pyruvate ratio. These markers are earlier than clinical abnormalities or pressure measurements (sensibility 82%, specificity 89%). In the field of head trauma, the same compounds were utilised. The level of these compounds correlates with outcome in a different manner whether the area studied is close to a concussion or not. Most of biochemical events are linked to global cerebral ischaemia. We can observe some abnormalities limited to the pericontusional area, which are not detected by the global monitoring. Microdialysis appears a useful tool to investigate disease mechanisms but cannot be recommended for a widespread use after head trauma.
Conclusion: Bedside cerebral microdialysis allows clinical decisions in the setting of subarachnoid haemorrhage and ischaemic stroke. It represents a valuable tool to investigate head trauma pathophysiology.