The purpose of this study is to assess the feasibility, safety and preliminary efficacy of the use of insulin infusions as treatment for hyperglycemic acute ischemic stroke patients.

Ischemic stroke is a common, devastating and costly disease. Half of acute stroke patients have elevated glucose levels upon admission to the hospital, and hyperglycemia is associated with poor outcome for post-stroke patients. It is unclear if treatment of hyperglycemia or glucose lowering improves outcome, however, in animal stroke models and other human conditions, aggressive glucose lowering is beneficial.

The goal of this multicenter trial is to determine if tight control of blood glucose is beneficial in hyperglycemic patients with acute ischemic stroke. In the trial, researchers will compare intravenous (IV) glucose insulin and potassium (GIK) therapy plus meal insulin to control therapy in 72 stroke patients.

Participants will be randomly assigned to one of three groups-(1) the control group with a target glucose level of <300mg/dL; (2) the tight control GIK plus meal insulin group with a target of <110mg/dL; or (3) the loose control GIK plus meal insulin group with a target of <200mg/dL-with all groups avoiding glucose levels of <70mg/dL.

The specific aims of this study are to collect preliminary data on the safety and feasibility of GIK for treatment of hyperglycemia in acute stroke patients, and to collect preliminary data comparing tight GIK therapy with loose GIK therapy and control therapy. Information learned in this study will compliment ongoing work and allow for maximum efficiency in the design of future treatment trials.

Inclusion Criteria:

• 18 years of age or older.
• Clinical diagnosis of ischemic stroke defined as acute neurological deficit occurring in one or more major vessels.
• Must arrive at hospital and be able to begin treatment within 2 hours of established eligibility and this must be within 24 hours of symptom onset. - - Patients unable to report symptom onset time or those awakening with symptoms must use the time last known to be well as the onset time.
• Admission plasma glucose of > 110 mg/dL.

Exclusion Criteria:

• Renal dysfunction as defined by a serum creatinine of >/=2.5 mg/dL at enrollment.
• Substantial pre-existing neurological or psychiatric illness that would confound neurological assessment.
• Patients who have received experimental therapy for the enrollment stroke.
• Pregnant females.
• Patients with other severe life threatening conditions that makes them unlikely to survive 90 days.
• Patients who are unable to follow the protocol or come back for 90-day followup.
• Patient has condition for which insulin infusion is the usual practice or the treating physician feels that there is an indication for insulin infusion.