Methemoglobin Concentration in High Dose Inhaled Nitric Oxide

The goal of this clinical trial is to learn about the kinetic of methemoglobin in healthy subjects breathing high dose inhaled nitric oxide.The main questions it aims to answer are:What are the kinetics of methemoglobin formation at different concentrations of nitric oxide and oxygenWhat are the kinetics of methemoglobin reduction after nitric oxide discontinuationParticipants will be exposed to intermittent high dose inhaled nitric oxide while being continuously monitored.

Inclusion Criteria:18 - 64 years-old volunteers.Body Mass Index (BMI) 18 - 30 kg/m2.Absence of current systemic and/or respiratory diseases.Capacity to consent to the study.Exclusion Criteria:Evidence of any physical, mental, and/or medical conditions that would make the proposed studies relatively more hazardous.Systemic and/or respiratory disease with or without any functional limitation.Left ventricle ejection fraction < 30%.Baseline MetHb ≥ 3%Other conditions of increased risk for MetHb formation: genetic diseases (e.g., glucose-6-phosphate dehydrogenase deficiency, cytochrome b5 reductase deficiency, sickle cell disease), significant anemia or baseline elevation in MetHb.History of transient ischemic attack or stroke.Active smoking and tobacco chewers. Volunteers may be enrolled if they quit smoking for more than 1 year and less than 10 pack years total.Any vaping/e-cigarettes useExcess alcohol use: more than ½ L/day of wine consumption or equivalentCurrent use of any recreational drugs (including the use of medical marijuana) or use of recreational drugs over the past year.Pregnancy determined by blood pregnancy test detecting presence of human chorionic gonadotropin (hCG).Less than six weeks postpartum.Any current medication uses except oral contraceptives.Lower respiratory infection within the last 30 days.Claustrophobia (inability to wear a facemask) or other active psychiatric conditions or unwillingness to cooperate with the investigators and other medical teams.Currently enrolled in another research study.Facial abnormalities that would preclude proper use of a face mask.