Transnasal Induction of Normothermia in Febrile Stroke Patients

Inclusion Criteria: 1. Admitted to the Neurosciences Critical Care Unit (NCCU). 2. Patient has ischemic or hemorrhagic stroke, seizure, or metabolic encephalopathy. 3. Patient is orally intubated or has tracheostomy tube and is mechanically ventilated. 4. Planned stay in NCCU \> 24 hours. 5. Must have informed consent from the patient or the legally authorized representative (LAR) Exclusion Criteria: 1. Age \< 18 years old or \> 95 years. 2. Intubation is contraindicated. 3. With a coagulopathy. INR above 1.5 or PTT above 45 seconds. 4. Hemodynamic instability, including elevated SPB for \>5 minutes despite standard of care interventions (SPB ≥ 160 mmHg for intracerebral hemorrhagic stroke; SPB ≥ 220 mmHg for subarachnoid hemorrhagic stroke or ischemic stroke). 5. History of cryoglobulinemia. 6. History of sickle cell disease. 7. History of serum cold agglutinin disease. 8. Active/ongoing of nose bleeds. 9. Known or suspected pregnancy. 10. Participation in another ongoing investigational study. 11. Prisoners and/or patients for whom no LAR is available. 12. Patient is in airborne/droplet disease isolation protocol. 13. Patient is or suspected to be immunocompromised; 14. Low platelet count defined as \< 100k (thrombocytopenia). 15. Nasal septal deviations (per CT scan; any degree). 16. Chronic rhinosinusitis. 17. Prior skull-based surgery 18. Penetrating cranial trauma. 19. Recent nasal trauma or anterior base skull fracture. 20. Presence of cardiac arrhythmias including: sustained tachycardia defined as heart rate above 120 beats per minute, or sustained bradycardia defined as heart rate below 60 beats per minute. 21. Refractory hypoxemia defined as partial pressure of oxygen in arterial blood (paO2) below 60 torr or oxyhemoglobin saturation below 90% despite endotracheal intubation, mechanical ventilation, and provision of supplemental oxygen of up to 0.60. 22. Refractory hypercarbia defined as partial pressure of carbon dioxide in arterial blood (paCO2) above 50 torr despite endotracheal intubation and conventional mechanical ventilation. 23. History of cardiac arrhythmia as listed above. 24. BMI of ≤ 15 kg/m2 or ≥ 40kg/m2