MULTIMODAL MONITORING AND ASSESSMENT OF CEREBRAL HEMODYNAMIC RESERVE AFTER SEVERE HEAD-INJURY

This article contains an overview of selected clinical techniques empl oyed for neurointensive care monitoring and testing of cerebral autore gulation of patients following severe head injury. Multiple modalities are used for monitoring of cerebral haemodynamic reserve, including i ntracranial pressure, cerebral perfusion pressure (CPP), blood flow ve locity (FV) in the middle cerebral artery (MCA), jugular bulb oxygen s aturation, laser-Doppler cortical flowmetry, near infrared spectroscop y of cerebral cortex, tissue oxygenation, and microdialysis. Large vol umes of information demand specialised computer support for sensible i nterpretation and filtration of artifacts. Methods of testing of cereb ral autoregulatory reserve based on transcranial Doppler ultrasonograp hy are reviewed. Repetitive or continuous assessment is important in p ractice as autoregulatory reserve may fluctuate in time. Static and dy namic rates of autoregulation show sensitivity to carbon dioxide-induc ed vasodilatation, but fail to correlate with outcome following head i njury. The carotid artery compression test, useful for assessment of p atients after subarachnoid haemorrhage, has yet to prove its usefulnes s in head injury. Continuous waveform analysis of MCA FV and CPP corre lates with coma score after resuscitation and outcome and hence may be considered as a robust method for the assessment of autoregulation in ventilated head trauma patients.