None

None

- covid-19 patients with mild to no respiratory distress, defined as p/f ratio > 200 mmhg. - intubated covid-19 patients ventilated with an fio2 of > 0.90 (reduction of fio2 at this level or higher when eno is blended into the ventilation circuit cannot be avoided). - patients that are ventilated with a device not certified for blending of other medical gases into the ventilator circuit. - physician of record opposed to enrolling the patient due to perceived safety concerns; or any condition that does not allow the protocol to be followed safely. - subjects with past medical history of lung malignancy or pneumonectomy or lung transplant - subjects who have a history of malignancy or other irreversible disease/conditions with a 6-month mortality > 50% - subjects that have experienced cardiac arrest with cpr for longer than 30 minutes - pregnancy - patients on extracorporeal membrane oxygenation (ecmo) - patient groups at an increased risk to form methemoglobin. (e.g. congenital variants of met-hb) - patients with anemia, defined as a hemoglobin of < 9 mg/dl

- covid-19 patients with mild to no respiratory distress, defined as p/f ratio > 200 mmhg. - intubated covid-19 patients ventilated with an fio2 of > 0.90 (reduction of fio2 at this level or higher when eno is blended into the ventilation circuit cannot be avoided). - patients that are ventilated with a device not certified for blending of other medical gases into the ventilator circuit. - physician of record opposed to enrolling the patient due to perceived safety concerns; or any condition that does not allow the protocol to be followed safely. - subjects with past medical history of lung malignancy or pneumonectomy or lung transplant - subjects who have a history of malignancy or other irreversible disease/conditions with a 6-month mortality > 50% - subjects that have experienced cardiac arrest with cpr for longer than 30 minutes - pregnancy - patients on extracorporeal membrane oxygenation (ecmo) - patient groups at an increased risk to form methemoglobin. (e.g. congenital variants of met-hb) - patients with anemia, defined as a hemoglobin of < 9 mg/dl