* patients with pneumonia with two or more of the following: 1. wbc of more than 15,000 2. lobar pneumonia 3. pleural effusion * patients who are treated with or require high flow nasal cannula, cpap, intubation, mechanical ventilation, or tracheostomy * breastfeeding or pregnancy as evidenced by a positive pregnancy test. * subjects diagnosed with immunodeficiency, with history of congestive or unstable heart disease, left ventricular dysfunction (lvef \<40%) or myocardial damage, severe pulmonary hypertension and/or unstable hypertension * use of an investigational drug during the last 30 days prior enrollment * methemoglobin level \>3% at screening * patients on chronic (over two weeks of treatment) systemic steroids (any formulation, excluding dexamethasone or prednisone) within 30 days prior to enrollment. * history of daily, continuous oxygen supplementation * patients with bmi greater than or equal to 40 * patients with clinically significant anemia, e.g., hb \<10.0 and/or thrombocytopenia, e.g., platelets \<75. * smokers who are unwilling to refrain from smoking during hospitalization * presence of a condition or abnormality that in the opinion of the investigator would compromise the safety of the subject or the quality of the data, e.g., known or suspected thalassemia, sickle cell disease or other diseases associated with poor oxygen carrying capacity. * the subject is identified by the investigator as being unable or unwilling to perform study procedures.

* patients with pneumonia with two or more of the following: 1. wbc of more than 15,000 2. lobar pneumonia 3. pleural effusion * patients who are treated with or require high flow nasal cannula, cpap, intubation, mechanical ventilation, or tracheostomy * breastfeeding or pregnancy as evidenced by a positive pregnancy test. * subjects diagnosed with immunodeficiency, with history of congestive or unstable heart disease, left ventricular dysfunction (lvef \<40%) or myocardial damage, severe pulmonary hypertension and/or unstable hypertension * use of an investigational drug during the last 30 days prior enrollment * methemoglobin level \>3% at screening * patients on chronic (over two weeks of treatment) systemic steroids (any formulation, excluding dexamethasone or prednisone) within 30 days prior to enrollment. * history of daily, continuous oxygen supplementation * patients with bmi greater than or equal to 40 * patients with clinically significant anemia, e.g., hb \<10.0 and/or thrombocytopenia, e.g., platelets \<75. * smokers who are unwilling to refrain from smoking during hospitalization * presence of a condition or abnormality that in the opinion of the investigator would compromise the safety of the subject or the quality of the data, e.g., known or suspected thalassemia, sickle cell disease or other diseases associated with poor oxygen carrying capacity. * the subject is identified by the investigator as being unable or unwilling to perform study procedures.

patients with pneumonia with two or more of the following: wbc of more than 15,000 lobar pneumonia pleural effusion patients who are treated with or require high flow nasal cannula, cpap, intubation, mechanical ventilation, or tracheostomy breastfeeding or pregnancy as evidenced by a positive pregnancy test. subjects diagnosed with immunodeficiency, with history of congestive or unstable heart disease, left ventricular dysfunction (lvef <40%) or myocardial damage, severe pulmonary hypertension and/or unstable hypertension use of an investigational drug during the last 30 days prior enrollment methemoglobin level >3% at screening patients on chronic (over two weeks of treatment) systemic steroids (any formulation, excluding dexamethasone or prednisone) within 30 days prior to enrollment. history of daily, continuous oxygen supplementation patients with bmi greater than or equal to 40 patients with clinically significant anemia, e.g., hb <10.0 and/or thrombocytopenia, e.g., platelets <75. smokers who are unwilling to refrain from smoking during hospitalization presence of a condition or abnormality that in the opinion of the investigator would compromise the safety of the subject or the quality of the data, e.g., known or suspected thalassemia, sickle cell disease or other diseases associated with poor oxygen carrying capacity. the subject is identified by the investigator as being unable or unwilling to perform study procedures.

patients with pneumonia with two or more of the following: wbc of more than 15,000 lobar pneumonia pleural effusion patients who are treated with or require high flow nasal cannula, cpap, intubation, mechanical ventilation, or tracheostomy breastfeeding or pregnancy as evidenced by a positive pregnancy test. subjects diagnosed with immunodeficiency, with history of congestive or unstable heart disease, left ventricular dysfunction (lvef <40%) or myocardial damage, severe pulmonary hypertension and/or unstable hypertension use of an investigational drug during the last 30 days prior enrollment methemoglobin level >3% at screening patients on chronic (over two weeks of treatment) systemic steroids (any formulation, excluding dexamethasone or prednisone) within 30 days prior to enrollment. history of daily, continuous oxygen supplementation patients with bmi greater than or equal to 40 patients with clinically significant anemia, e.g., hb <10.0 and/or thrombocytopenia, e.g., platelets <75. smokers who are unwilling to refrain from smoking during hospitalization presence of a condition or abnormality that in the opinion of the investigator would compromise the safety of the subject or the quality of the data, e.g., known or suspected thalassemia, sickle cell disease or other diseases associated with poor oxygen carrying capacity. the subject is identified by the investigator as being unable or unwilling to perform study procedures.

- patients who are treated with or require high flow nasal cannula, cpap, intubation, mechanical ventilation, or tracheostomy - breastfeeding or pregnancy as evidenced by a positive pregnancy test. - subjects diagnosed with immunodeficiency, with history of congestive or unstable heart disease, left ventricular dysfunction (lvef <40%) or myocardial damage, severe pulmonary hypertension and/or unstable hypertension - use of an investigational drug during the last 30 days prior enrollment - methemoglobin level >3% at screening - patients on chronic (over two weeks of treatment) systemic steroids (any formulation, excluding dexamethasone) within 30 days prior to enrollment. - history of daily, continuous oxygen supplementation - patients with bmi greater than or equal to 40 - patients with clinically significant anemia, e.g., hb <10.0 and/or thrombocytopenia, e.g., platelets <75. - smokers who are unwilling to refrain from smoking during hospitalization - presence of a condition or abnormality that in the opinion of the investigator would compromise the safety of the subject or the quality of the data, e.g., known or suspected thalassemia, sickle cell disease or other diseases associated with poor oxygen carrying capacity. - the subject is identified by the investigator as being unable or unwilling to perform study procedures.

- patients who are treated with or require high flow nasal cannula, cpap, intubation, mechanical ventilation, or tracheostomy - breastfeeding or pregnancy as evidenced by a positive pregnancy test. - subjects diagnosed with immunodeficiency, with history of congestive or unstable heart disease, left ventricular dysfunction (lvef <40%) or myocardial damage, severe pulmonary hypertension and/or unstable hypertension - use of an investigational drug during the last 30 days prior enrollment - methemoglobin level >3% at screening - patients on chronic (over two weeks of treatment) systemic steroids (any formulation, excluding dexamethasone) within 30 days prior to enrollment. - history of daily, continuous oxygen supplementation - patients with bmi greater than or equal to 40 - patients with clinically significant anemia, e.g., hb <10.0 and/or thrombocytopenia, e.g., platelets <75. - smokers who are unwilling to refrain from smoking during hospitalization - presence of a condition or abnormality that in the opinion of the investigator would compromise the safety of the subject or the quality of the data, e.g., known or suspected thalassemia, sickle cell disease or other diseases associated with poor oxygen carrying capacity. - the subject is identified by the investigator as being unable or unwilling to perform study procedures.