1. patients on invasive mechanical ventilation (e.g., endotracheal intubation) 2. chronic home oxygen utilization 3. home or current use of immunosuppressive medications (including steroids) 4. women who are pregnant, breastfeeding, or become pregnant during the study 5. patients on non-invasive positive pressure ventilation 6. patients on \>12 liters per minute via non-rebreather (nrb) or \>80% oxygen via high flow nasal cannula 7. patients who, in the opinion of the pi, have impending respiratory failure, defined as requiring rapidly escalating oxygen supplementation 8. patients with a hemoglobin \<9 mg/dl 9. patients diagnosed with stage 4 or 5 chronic kidney disease (ckd) 10. patients with diagnosed new york heart association (nyha) class 4 or 5 congestive heart failure 11. patients with a left ventricular assist device (lvad) 12. patients with thromboembolic phenomena 13. patients with type 2 and above heart block 14. patients with established positive bacterial blood cultures prior to enrollment 15. patients with ongoing pericardial effusion or ascites 16. patients with clinically significant arrhythmia 17. patients with liver function tests (alt or ast) \>3x normal 18. patients with untreated hiv infection 19. patients diagnosed with end-stage organ disease

1. patients on invasive mechanical ventilation (e.g., endotracheal intubation) 2. chronic home oxygen utilization 3. home or current use of immunosuppressive medications (including steroids) 4. women who are pregnant, breastfeeding, or become pregnant during the study 5. patients on non-invasive positive pressure ventilation 6. patients on \>12 liters per minute via non-rebreather (nrb) or \>80% oxygen via high flow nasal cannula 7. patients who, in the opinion of the pi, have impending respiratory failure, defined as requiring rapidly escalating oxygen supplementation 8. patients with a hemoglobin \<9 mg/dl 9. patients diagnosed with stage 4 or 5 chronic kidney disease (ckd) 10. patients with diagnosed new york heart association (nyha) class 4 or 5 congestive heart failure 11. patients with a left ventricular assist device (lvad) 12. patients with thromboembolic phenomena 13. patients with type 2 and above heart block 14. patients with established positive bacterial blood cultures prior to enrollment 15. patients with ongoing pericardial effusion or ascites 16. patients with clinically significant arrhythmia 17. patients with liver function tests (alt or ast) \>3x normal 18. patients with untreated hiv infection 19. patients diagnosed with end-stage organ disease

patients on invasive mechanical ventilation (e.g., endotracheal intubation) chronic home oxygen utilization home or current use of immunosuppressive medications (including steroids) women who are pregnant, breastfeeding, or become pregnant during the study patients on non-invasive positive pressure ventilation patients on >12 liters per minute via non-rebreather (nrb) or >80% oxygen via high flow nasal cannula patients who, in the opinion of the pi, have impending respiratory failure, defined as requiring rapidly escalating oxygen supplementation patients with a hemoglobin <9 mg/dl patients diagnosed with stage 4 or 5 chronic kidney disease (ckd) patients with diagnosed new york heart association (nyha) class 4 or 5 congestive heart failure patients with a left ventricular assist device (lvad) patients with thromboembolic phenomena patients with type 2 and above heart block patients with established positive bacterial blood cultures prior to enrollment patients with ongoing pericardial effusion or ascites patients with clinically significant arrhythmia patients with liver function tests (alt or ast) >3x normal patients with untreated hiv infection patients diagnosed with end-stage organ disease

patients on invasive mechanical ventilation (e.g., endotracheal intubation) chronic home oxygen utilization home or current use of immunosuppressive medications (including steroids) women who are pregnant, breastfeeding, or become pregnant during the study patients on non-invasive positive pressure ventilation patients on >12 liters per minute via non-rebreather (nrb) or >80% oxygen via high flow nasal cannula patients who, in the opinion of the pi, have impending respiratory failure, defined as requiring rapidly escalating oxygen supplementation patients with a hemoglobin <9 mg/dl patients diagnosed with stage 4 or 5 chronic kidney disease (ckd) patients with diagnosed new york heart association (nyha) class 4 or 5 congestive heart failure patients with a left ventricular assist device (lvad) patients with thromboembolic phenomena patients with type 2 and above heart block patients with established positive bacterial blood cultures prior to enrollment patients with ongoing pericardial effusion or ascites patients with clinically significant arrhythmia patients with liver function tests (alt or ast) >3x normal patients with untreated hiv infection patients diagnosed with end-stage organ disease

patients on invasive mechanical ventilation (e.g., endotracheal intubation) chronic home oxygen utilization home or current use of immunosuppressive medications (including steroids) women who are pregnant, breastfeeding, or become pregnant during the study patients on non-invasive positive pressure ventilation patients on >12 liters per minute via non-rebreather (nrb) or >80% oxygen via high flow nasal cannula patients who, in the opinion of the pi, have impending respiratory failure, defined as requiring rapidly escalating oxygen supplementation patients with a hemoglobin <9 mg/dl patients diagnosed with stage 4 or 5 chronic kidney disease (ckd) patients with diagnosed nyha class 4 or 5 congestive heart failure patients with a left ventricular assist device (lvad) patients with thromboembolic phenomena patients with type 2 and above heart block patients with established positive bacterial blood cultures prior to enrollment patients with ongoing pericardial effusion or ascites patients with clinically significant arrhythmia patients with liver function tests (alt or ast) >3x normal patients with untreated hiv infection patients diagnosed with end-stage organ disease

patients on invasive mechanical ventilation (e.g., endotracheal intubation) chronic home oxygen utilization home or current use of immunosuppressive medications (including steroids) women who are pregnant, breastfeeding, or become pregnant during the study patients on non-invasive positive pressure ventilation patients on >12 liters per minute via non-rebreather (nrb) or >80% oxygen via high flow nasal cannula patients who, in the opinion of the pi, have impending respiratory failure, defined as requiring rapidly escalating oxygen supplementation patients with a hemoglobin <9 mg/dl patients diagnosed with stage 4 or 5 chronic kidney disease (ckd) patients with diagnosed nyha class 4 or 5 congestive heart failure patients with a left ventricular assist device (lvad) patients with thromboembolic phenomena patients with type 2 and above heart block patients with established positive bacterial blood cultures prior to enrollment patients with ongoing pericardial effusion or ascites patients with clinically significant arrhythmia patients with liver function tests (alt or ast) >3x normal patients with untreated hiv infection patients diagnosed with end-stage organ disease

1. patients on invasive mechanical ventilation (e.g., endotracheal intubation) 2. chronic home oxygen utilization 3. home or current use of immunosuppressive medications (including steroids) 4. women who are pregnant, breastfeeding, or become pregnant during the study 5. patients on non-invasive positive pressure ventilation 6. patients on >12 liters per minute via non-rebreather (nrb) or >80% oxygen via high flow nasal cannula 7. patients who, in the opinion of the pi, have impending respiratory failure, defined as requiring rapidly escalating oxygen supplementation 8. patients with a hemoglobin <9 mg/dl 9. patients diagnosed with stage 4 or 5 chronic kidney disease (ckd) 10. patients with diagnosed nyha class 4 or 5 congestive heart failure 11. patients with a left ventricular assist device (lvad) 12. patients with thromboembolic phenomena 13. patients with type 2 and above heart block 14. patients with established positive bacterial blood cultures prior to enrollment 15. patients with ongoing pericardial effusion or ascites 16. patients with clinically significant arrhythmia 17. patients with liver function tests (alt or ast) >3x normal 18. patients with untreated hiv infection 19. patients diagnosed with end-stage organ disease

1. patients on invasive mechanical ventilation (e.g., endotracheal intubation) 2. chronic home oxygen utilization 3. home or current use of immunosuppressive medications (including steroids) 4. women who are pregnant, breastfeeding, or become pregnant during the study 5. patients on non-invasive positive pressure ventilation 6. patients on >12 liters per minute via non-rebreather (nrb) or >80% oxygen via high flow nasal cannula 7. patients who, in the opinion of the pi, have impending respiratory failure, defined as requiring rapidly escalating oxygen supplementation 8. patients with a hemoglobin <9 mg/dl 9. patients diagnosed with stage 4 or 5 chronic kidney disease (ckd) 10. patients with diagnosed nyha class 4 or 5 congestive heart failure 11. patients with a left ventricular assist device (lvad) 12. patients with thromboembolic phenomena 13. patients with type 2 and above heart block 14. patients with established positive bacterial blood cultures prior to enrollment 15. patients with ongoing pericardial effusion or ascites 16. patients with clinically significant arrhythmia 17. patients with liver function tests (alt or ast) >3x normal 18. patients with untreated hiv infection 19. patients diagnosed with end-stage organ disease