1. evidence of critical covid-19 2. inability to utilize nebulized drugs, or history of bronchospasm with inhaled medications 3. age \<12 years; 4. mean arterial pressure \< 65 mm hg after initial hospital stabilization, 5. non-covid-19 irreversible underlying condition with projected fatal course within 6 months or with high risk of mortality; 6. immunosuppressive treatment for transplant or other diseases associated with high mortality; 7. stage iv cancer or cancer on active treatment with chemotherapy immunotherapy or checkpoint inhibitors; acute renal failure or chronic renal insufficiency with gfr less than 30; chf new york heart association class iii or iv, new neurologic disorder in the last 3 months or chronic neurologic disorder or other that would impact on assessing the resolution of severe covid-19 respiratory failure 8. myocardial infarction in previous six months or troponin \>0.5 9. recent history of venous thrombotic events (pe / dvt) within the last 3 months. 10. new diagnosis of atrial fibrillation within the last 3 months. acceptable if greater than 3 months and well controlled in the opinion of the investigator 11. watery diarrhea requiring replacement of 1 liter or more of iv fluids and electrolytes 12. pregnancy

1. evidence of critical covid-19 2. inability to utilize nebulized drugs, or history of bronchospasm with inhaled medications 3. age \<12 years; 4. mean arterial pressure \< 65 mm hg after initial hospital stabilization, 5. non-covid-19 irreversible underlying condition with projected fatal course within 6 months or with high risk of mortality; 6. immunosuppressive treatment for transplant or other diseases associated with high mortality; 7. stage iv cancer or cancer on active treatment with chemotherapy immunotherapy or checkpoint inhibitors; acute renal failure or chronic renal insufficiency with gfr less than 30; chf new york heart association class iii or iv, new neurologic disorder in the last 3 months or chronic neurologic disorder or other that would impact on assessing the resolution of severe covid-19 respiratory failure 8. myocardial infarction in previous six months or troponin \>0.5 9. recent history of venous thrombotic events (pe / dvt) within the last 3 months. 10. new diagnosis of atrial fibrillation within the last 3 months. acceptable if greater than 3 months and well controlled in the opinion of the investigator 11. watery diarrhea requiring replacement of 1 liter or more of iv fluids and electrolytes 12. pregnancy

evidence of critical covid-19 inability to utilize nebulized drugs, or history of bronchospasm with inhaled medications age <12 years; mean arterial pressure < 65 mm hg after initial hospital stabilization, non-covid-19 irreversible underlying condition with projected fatal course within 6 months or with high risk of mortality; immunosuppressive treatment for transplant or other diseases associated with high mortality; stage iv cancer or cancer on active treatment with chemotherapy immunotherapy or checkpoint inhibitors; acute renal failure or chronic renal insufficiency with gfr less than 30; chf new york heart association class iii or iv, new neurologic disorder in the last 3 months or chronic neurologic disorder or other that would impact on assessing the resolution of severe covid-19 respiratory failure myocardial infarction in previous six months or troponin >0.5 recent history of venous thrombotic events (pe / dvt) within the last 3 months. new diagnosis of atrial fibrillation within the last 3 months. acceptable if greater than 3 months and well controlled in the opinion of the investigator watery diarrhea requiring replacement of 1 liter or more of iv fluids and electrolytes pregnancy

evidence of critical covid-19 inability to utilize nebulized drugs, or history of bronchospasm with inhaled medications age <12 years; mean arterial pressure < 65 mm hg after initial hospital stabilization, non-covid-19 irreversible underlying condition with projected fatal course within 6 months or with high risk of mortality; immunosuppressive treatment for transplant or other diseases associated with high mortality; stage iv cancer or cancer on active treatment with chemotherapy immunotherapy or checkpoint inhibitors; acute renal failure or chronic renal insufficiency with gfr less than 30; chf new york heart association class iii or iv, new neurologic disorder in the last 3 months or chronic neurologic disorder or other that would impact on assessing the resolution of severe covid-19 respiratory failure myocardial infarction in previous six months or troponin >0.5 recent history of venous thrombotic events (pe / dvt) within the last 3 months. new diagnosis of atrial fibrillation within the last 3 months. acceptable if greater than 3 months and well controlled in the opinion of the investigator watery diarrhea requiring replacement of 1 liter or more of iv fluids and electrolytes pregnancy

1. evidence of critical covid-19 2. inability to utilize nebulized drugs, or history of bronchospasm with inhaled medications 3. age <12 years; 4. mean arterial pressure < 65 mm hg after initial hospital stabilization, 5. non-covid-19 irreversible underlying condition with projected fatal course within 6 months or with high risk of mortality; 6. immunosuppressive treatment for transplant or other diseases associated with high mortality; 7. stage iv cancer or cancer on active treatment with chemotherapy immunotherapy or checkpoint inhibitors; acute renal failure or chronic renal insufficiency with gfr less than 30; chf new york heart association class iii or iv, new neurologic disorder in the last 3 months or chronic neurologic disorder or other that would impact on assessing the resolution of severe covid-19 respiratory failure 8. myocardial infarction in previous six months or troponin >0.5 9. recent history of venous thrombotic events (pe / dvt) within the last 3 months. 10. new diagnosis of atrial fibrillation within the last 3 months. acceptable if greater than 3 months and well controlled in the opinion of the investigator 11. watery diarrhea requiring replacement of 1 liter or more of iv fluids and electrolytes 12. pregnancy

1. evidence of critical covid-19 2. inability to utilize nebulized drugs, or history of bronchospasm with inhaled medications 3. age <12 years; 4. mean arterial pressure < 65 mm hg after initial hospital stabilization, 5. non-covid-19 irreversible underlying condition with projected fatal course within 6 months or with high risk of mortality; 6. immunosuppressive treatment for transplant or other diseases associated with high mortality; 7. stage iv cancer or cancer on active treatment with chemotherapy immunotherapy or checkpoint inhibitors; acute renal failure or chronic renal insufficiency with gfr less than 30; chf new york heart association class iii or iv, new neurologic disorder in the last 3 months or chronic neurologic disorder or other that would impact on assessing the resolution of severe covid-19 respiratory failure 8. myocardial infarction in previous six months or troponin >0.5 9. recent history of venous thrombotic events (pe / dvt) within the last 3 months. 10. new diagnosis of atrial fibrillation within the last 3 months. acceptable if greater than 3 months and well controlled in the opinion of the investigator 11. watery diarrhea requiring replacement of 1 liter or more of iv fluids and electrolytes 12. pregnancy

1. evidence of critical covid-19 2. inability to utilize nebulized drugs, or history of bronchospasm with inhaled medications 3. age <18 years; 4. mean arterial pressure < 65 mm hg after initial hospital stabilization, 5. non-covid-19 irreversible underlying condition with projected fatal course within 6 months or with high risk of mortality; 6. immunosuppressive treatment for transplant or other diseases associated with high mortality; 7. stage iv cancer or cancer on active treatment with chemotherapy immunotherapy or checkpoint inhibitors; acute renal failure or chronic renal insufficiency with gfr less than 30; chf new york heart association class iii or iv, new neurologic disorder in the last 3 months or chronic neurologic disorder or other that would impact on assessing the resolution of severe covid-19 respiratory failure 8. myocardial infarction in previous six months or troponin >0.5 9. recent history of venous thrombotic events (pe / dvt) within the last 3 months. 10. new diagnosis of atrial fibrillation within the last 3 months. acceptable if greater than 3 months and well controlled in the opinion of the investigator 11. watery diarrhea requiring replacement of 1 liter or more of iv fluids and electrolytes 12. pregnancy

1. evidence of critical covid-19 2. inability to utilize nebulized drugs, or history of bronchospasm with inhaled medications 3. age <18 years; 4. mean arterial pressure < 65 mm hg after initial hospital stabilization, 5. non-covid-19 irreversible underlying condition with projected fatal course within 6 months or with high risk of mortality; 6. immunosuppressive treatment for transplant or other diseases associated with high mortality; 7. stage iv cancer or cancer on active treatment with chemotherapy immunotherapy or checkpoint inhibitors; acute renal failure or chronic renal insufficiency with gfr less than 30; chf new york heart association class iii or iv, new neurologic disorder in the last 3 months or chronic neurologic disorder or other that would impact on assessing the resolution of severe covid-19 respiratory failure 8. myocardial infarction in previous six months or troponin >0.5 9. recent history of venous thrombotic events (pe / dvt) within the last 3 months. 10. new diagnosis of atrial fibrillation within the last 3 months. acceptable if greater than 3 months and well controlled in the opinion of the investigator 11. watery diarrhea requiring replacement of 1 liter or more of iv fluids and electrolytes 12. pregnancy

1. evidence of respiratory failure 2. use or impending use of ventilation or high flow nasal oxygen 20l or greater 4) age <12 years; 5) diastolic pressure < 65 mm hg; 6) irreversible underlying condition with projected fatal course; 7) immunosuppressive treatment for transplant or other reasons; 8) cancer, renal failure, congestive heart failure, neurological disorder 9) recent myocardial infarction with troponin >0.5

1. evidence of respiratory failure 2. use or impending use of ventilation or high flow nasal oxygen 20l or greater 4) age <12 years; 5) diastolic pressure < 65 mm hg; 6) irreversible underlying condition with projected fatal course; 7) immunosuppressive treatment for transplant or other reasons; 8) cancer, renal failure, congestive heart failure, neurological disorder 9) recent myocardial infarction with troponin >0.5