Cerebral Autoregulation

The human brain is by far the most expensive organ in terms of energy expenditure in the whole body, characterized by high metabolic activity with fine regulatory mechanisms, defined as cerebral autoregulation, to ensure adequate energy substrates supply in register with brain activity. The classic, long-term steady-state or static, cerebral autoregulation denotes that cerebral blood flow is independent of the changes of mean arterial blood pressure within a wide range of blood pressure. The recent dynamic approach allows differentiation of the cerebral autoregulation response to fluctuations in beat-to-beat blood pressure of different magnitudes and durations. The mechanisms of cerebral autoregulation remain poorly understood. It is clear that cerebral autoregulation is multifactorial phenomenon of the cerebral circulation, including myogenic, autonomic, and metabolic mechanisms. Harnessing cerebral autoregulation as a basis for therapy remains mostly conceptual. There is increasing evidence that multimodality monitoring of cerebral autoregulation might aid prognostication and help identify optimal cerebral perfusion pressure level in patients of ischemic stroke and traumatic brain injury. In the future, such monitoring may facilitate patients-specific control of cerebral autoregulation, hence, improve outcome of different neurological diseases.