EXTEND is a dose escalation study of NanO2™ in patients with mild respiratory distress who are at risk for mechanical ventilation. The study will establish dosing guidelines for a Phase 2 study.

Inclusion Criteria:

• Requiring supplemental oxygen but ≤ 6L oxygen by nasal cannula to maintain an oxygen saturation >92% or PaO2 >60mmHg
• Admitted to a hospital with symptoms of mild RD
• Signed informed consent obtained from the subject or subject's legally authorized representative
• Agrees to not participate in another clinical trial for the treatment of mild RD through Day 28

Exclusion Criteria:

• Presence of extracorporeal membrane oxygenation
• Unstable hypertension
• History of significantly impaired renal function defined as an eGFR ≤ 30mL/min/1.73m2 (MDRD equation or similar) or impaired hepatic function defined as the presence of decompensated cirrhosis (acute deterioration in liver function characterized by jaundice, ascites, hepatic encephalopathy, hepatorenal syndrome, or variceal hemorrhage)
• Presence of pulmonary embolism at baseline
• Evidence of right ventricular heart failure
• Unstable hemodynamically as defined by receiving 0.5μg/kg/min or greater norepinephrine
• Inability to comply with the study procedures
• Currently pregnant or breastfeeding
• Anticipated discharge from the hospital or transfer to another hospital which is not a study site within 48 hours
• History or evidence of any other clinically significant condition that, in the opinion of the investigator, might pose a safety risk to subjects or interfere with study procedures, evaluation, or completion