In the UK alone, approximate 100,000 people suffer a stroke each year. Improved management of stroke patients not only reduces morbidity and mortality, but also reduces the cost of long term social care. 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 changes can occur after stroke, this could result in brain bleeding and swelling where there is a reduced blood flow to the brain.