Near-Infrared Spectroscopy Comparison Study

Inclusion Criteria:

1. Provide written informed consent from patient or legally authorized representative before surgery
2. Adult patients 18-65 years of age
3. Presenting for elective or urgent total aortic arch repair under moderate hypothermic circulatory arrest (Nasopharyngeal temperature 20 - 24 ºC) with selective antegrade cerebral perfusion -

Exclusion Criteria:

1. Patients will be excluded from this study if they are age less than 18
2. Are undergoing an emergent procedure
3. Have a history of insulin-dependent diabetes mellitus
4. Have a history of stroke
5. Are undergoing a redo sternotomy during which major bleeding occurs necessitating transfusion of > 4 units of packed red blood cells prior to the institution of circulatory arrest
6. Patients in whom a left jugular venous bulb cannula cannot successfully be placed