WIN Ratio Analysis to Determine a Strategy of Non- Invasive SUpport for Respiratory Failure in the EmeRgency Department

Inclusion Criteria: * Age ≥18 years * Presenting to the Emergency Department (ED) with Acute Hypoxemic Respiratory failure (AHRF), defined as: * \[(respiratory rate ≥25 breaths/min) AND (requiring ≥6 L/min of oxygen required to maintain SpO2 ≥90%), OR SpO2:FiO2 ratio\<250\] OR * Arrival at ED on prehospital Non-Invasive Respiratory Support (NIRS). * Clinical need for NIRS * Randomization ≤2 hours after identification of need for NIRS * Randomization ≤6 hours of ED arrival Exclusion Criteria: * Urgent need for intubation * Cardiac arrest * Respiratory arrest * Patient not located in the ED * Craniofacial anatomic features that prohibit either Non-Invasive Positive Pressure Ventilation (NIPPV) or High Flow Nasal Oxygen (HFNO) interface * Tracheostomy or laryngectomy stoma * Hemodynamic instability requiring \>0.2mcg/kg/min of norepinepherine (or equivalent) to maintain mean arterial pressure \>65mmHg * Pre-existing "do not resuscitate" or "do not intubate" order * Home use of non-invasive positive-pressure ventilation for respiratory support of a medical condition other than sleep apnea * Transferred from another Emergency Department * History of advanced chronic obstructive pulmonary disease * History of advanced heart failure * Presence of opt-out identification * Prisoner * Known or apparent pregnant * Previous enrollment in WINDSURFER * A patient-specific contraindication makes one assigned study intervention unsafe