Inclusion Criteria1. Acute ischemic stroke due to large intracranial vessel occlusion demonstrated on CT-angiography in the following anterior circulation locations that will be treated by endovascular therapy (EVT):
1. Internal Carotid Artery (terminal "T" or "L-type"- occlusion or Cervical Carotid occlusion)
2. Middle Cerebral Artery (MCA) M1 or proximal M2
3. Anterior Cerebral Artery (ACA) A1 or proximal A2 •Patients who receive IV-tPA thrombolysis are eligible provided the drug was delivered within 4.5 hours of stroke onset or last seen normal and in accordance with local hospital standard of care.
2. Ages 18-80.
3. National Institute of Health Stroke Scale (NIHSS) score 8-30
4. Time of from stroke symptom onset of last seen normal to start of EVT (defined as groin puncture) < 6 hours.
5. Alberta Stroke Program Early Computed Tomography Score (ASPECTS) ≥ 6
6. Subject willing/able to return for protocol required follow up visits.
7. No significant pre-stroke disability (modified Rankin Score must be ≤ 2).
8. Females of childbearing potential must have a negative serum or urine pregnancy test.
9. Patient or patient's legally authorized representative has given Informed Consent according to Good Clinical Practices (GCP) and/or local IRB policies.
Exclusion Criteria1. Coma on admission (Glasgow Coma Scale <8), need for intubation upon ED arrival, or transferred patients who present previously intubated.
2. Severe agitation or seizures on admission that preclude safe vascular access.
3. Loss of airway protective reflexes and/or vomiting on admission.
4. Predicted or known difficult airway.
5. Pre-existing neurological or psychiatric disease that would confound the neurological or functional evaluations, e.g. dementia.
6. Presumed septic embolus, or suspicion of bacterial endocarditis
7. Currently participating or has participated in any investigational drug or device study within 30 days.
8. Inability to follow-up for 90-day assessment.