 The reliance on IV vasopressors, which are only administered in the intensive care unit, is a fundamental limitation of prior research. An alternative, but untested, approach is to use the oral vasopressor midodrine hydrochloride. We hypothesize that frequent midodrine dosing after AIS can optimize collateral blood flow and help salvage the ischemic penumbra. The objective of this study is to develop tools to quantify midodrines effect on blood pressure and the ischemic penumbra. 