Understanding and monitoring brain injury: the role of cerebral microdialysis

Excerpt

Neurointensive care should focus on individualised therapy to limit secondary cerebral damage, i.e. the numerous pathogenic events (oedema, ischemia, impaired metabolism, seizures, excitoxicity, inflammation, etc.) taking place in the hours or days following acute brain injury (ABI) that may further aggravate outcome. Management using information from intracranial pressure (ICP) and cerebral perfusion pressure (CPP) monitoring remains an important focus of neurointensive care; however, this may be insufficient to determine optimal treatment strategies and to change patient prognosis [1]. Lack of effectiveness of therapy targeted to ICP/CPP may partly be because ICP monitoring fails to capture more complex secondary cerebral physiologic derangements that, if identified and effectively treated, could potentially improve outcomes. Cerebral microdialysis (CMD) allows a scrutiny of tissue biochemistry and enables clinicians to monitor the metabolic state of the injured brain [2]. Most attention has been directed towards patients with severe TBI (sTBI) and aneurysmal subarachnoid haemorrhage (aSAH). Protocols guided by CMD monitoring, in combination with ICP and other monitoring modalities (brain tissue PO₂, EEG), are therefore increasingly used. Such protocols have evolved from the recognition that microdialysis parameters relate to outcome [3] and that brain chemistry can be changed with therapy [4]. …