This is a randomized, double-blind, placebo-controlled study to assess the efficacy and safety of pulsed iNO compared to placebo in subjects with COVID-19 who are hospitalized and require supplemental oxygen without assisted ventilation. Subjects will be randomized to receive placebo or iNO125 mcg/kg ideal body weight (IBW)/hour 24 hours daily up to 14 days or until resolution or discharge.

