Transnasal Induction of Normothermia for Neurogenic Fever

Inclusion Criteria: 1. Admitted to an Intensive Care Unit for a planned stay of at least 24 hours with a diagnosis of ischemic or hemorrhagic stroke, seizure, or metabolic encephalopathy. 2. Ages 18-85 years, inclusive. 3. Patient has fever ≥ 38.3°C and ≤ 38.9°C at the time of treatment initiation. 4. Patient is orally intubated or has tracheostomy tube and is mechanically ventilated. 5. Glasgow Coma Scale score of 3-11, inclusive. 6. Must have informed consent from the patient or the legally authorized representative (LAR) making decisions for the patient. Exclusion Criteria: 1. Intubation is contraindicated. 2. Weight of ≤ 100lb or ≥ 250lb. 3. Active/ongoing epistaxis. 4. Known or suspected pregnancy. 5. Participation in another ongoing investigational study. 6. Prisoners and/or patients for whom no LAR is available. 7. Patient is in airborne/droplet disease isolation protocol. 8. Patient is or suspected to be immunocompromised. 9. Nasal septal deviations (per standard of care CT scan; any degree). 10. Chronic rhinosinusitis. 11. Traumatic brain injury. 12. Prior skull-base surgery. 13. Penetrating cranial trauma. 14. Recent nasal trauma or anterior base skull fracture. 15. Any condition for which transnasal air flow would be contraindicated. 16. Refractory hypoxemia (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). 17. Refractory hypercarbia (partial pressure of carbon dioxide in arterial blood (paCO2) above 50 torr despite endotracheal intubation and conventional mechanical ventilation).