The brain has control systems (i.e.cerebral autoregulation) to maintain blood flow to the brain, over a relatively wide blood pressure range. Cerebral Autoregulation can be described as static, reflecting the integrity of such mechanisms over time, or dynamic, occurring in response to sudden fluctuations in perfusion pressure. When blood pressure drops, small arteries increase in size to restore flow levels, and when blood pressure rises, they narrow to protect the most delicate blood vessels. It is known that sudden decompensated blood pressure (BP) changes can occur after stroke, this could result in brain bleeding and swelling when there is uncontrolled increased blood flow, or reduce the viability of tissue surrounding the stroke area when there is reduced blood flow to the brain.