1. unable to understand and provide voluntary informed consent 2. current infection with hiv-1, hiv-2, hepatitis b, hepatitis c or htlv 3. history of malignancy, other than non-melanoma skin cancer or non-metastatic prostate cancer 4. currently receiving extracorporeal life support or high-frequency oscillatory ventilation 5. weight \> 150 kg 6. current severe chronic respiratory disease, as demonstrated by: 1. paco2 \> 50 mm hg, or 2. history of use of home oxygen 7. major trauma within the past 7 days 8. lung transplant recipient 9. who class iii or iv pulmonary hypertension 10. documented deep vein thrombosis or pulmonary embolism within the past 3 months 11. currently pregnant or lactating 12. currently participating in another clinical trial, or participation in another clinical trial within 30 days of enrollment 13. hypersensitivity to dextran-40 or dimethyl sulfoxide (dmso) 14. current pharmacotherapy using hydroxychloroquine or interleukin-6 inhibitors 15. history of cva or mi within 180 days of study enrollment

1. unable to understand and provide voluntary informed consent 2. current infection with hiv-1, hiv-2, hepatitis b, hepatitis c or htlv 3. history of malignancy, other than non-melanoma skin cancer or non-metastatic prostate cancer 4. currently receiving extracorporeal life support or high-frequency oscillatory ventilation 5. weight \> 150 kg 6. current severe chronic respiratory disease, as demonstrated by: 1. paco2 \> 50 mm hg, or 2. history of use of home oxygen 7. major trauma within the past 7 days 8. lung transplant recipient 9. who class iii or iv pulmonary hypertension 10. documented deep vein thrombosis or pulmonary embolism within the past 3 months 11. currently pregnant or lactating 12. currently participating in another clinical trial, or participation in another clinical trial within 30 days of enrollment 13. hypersensitivity to dextran-40 or dimethyl sulfoxide (dmso) 14. current pharmacotherapy using hydroxychloroquine or interleukin-6 inhibitors 15. history of cva or mi within 180 days of study enrollment

unable to understand and provide voluntary informed consent current infection with hiv-1, hiv-2, hepatitis b, hepatitis c or htlv history of malignancy, other than non-melanoma skin cancer or non-metastatic prostate cancer currently receiving extracorporeal life support or high-frequency oscillatory ventilation weight > 150 kg current severe chronic respiratory disease, as demonstrated by: paco2 > 50 mm hg, or history of use of home oxygen major trauma within the past 7 days lung transplant recipient who class iii or iv pulmonary hypertension documented deep vein thrombosis or pulmonary embolism within the past 3 months currently pregnant or lactating currently participating in another clinical trial, or participation in another clinical trial within 30 days of enrollment hypersensitivity to dextran-40 or dimethyl sulfoxide (dmso) current pharmacotherapy using hydroxychloroquine or interleukin-6 inhibitors history of cva or mi within 180 days of study enrollment

unable to understand and provide voluntary informed consent current infection with hiv-1, hiv-2, hepatitis b, hepatitis c or htlv history of malignancy, other than non-melanoma skin cancer or non-metastatic prostate cancer currently receiving extracorporeal life support or high-frequency oscillatory ventilation weight > 150 kg current severe chronic respiratory disease, as demonstrated by: paco2 > 50 mm hg, or history of use of home oxygen major trauma within the past 7 days lung transplant recipient who class iii or iv pulmonary hypertension documented deep vein thrombosis or pulmonary embolism within the past 3 months currently pregnant or lactating currently participating in another clinical trial, or participation in another clinical trial within 30 days of enrollment hypersensitivity to dextran-40 or dimethyl sulfoxide (dmso) current pharmacotherapy using hydroxychloroquine or interleukin-6 inhibitors history of cva or mi within 180 days of study enrollment

1. unable to understand and provide voluntary informed consent 2. current infection with hiv-1, hiv-2, hepatitis b, hepatitis c or htlv 3. history of malignancy, other than non-melanoma skin cancer or non-metastatic prostate cancer 4. currently receiving extracorporeal life support or high-frequency oscillatory ventilation 5. weight > 150 kg 6. current severe chronic respiratory disease, as demonstrated by: 1. paco2 > 50 mm hg, or 2. history of use of home oxygen 7. major trauma within the past 7 days 8. lung transplant recipient 9. who class iii or iv pulmonary hypertension 10. documented deep vein thrombosis or pulmonary embolism within the past 3 months 11. currently pregnant or lactating 12. currently participating in another clinical trial, or participation in another clinical trial within 30 days of enrollment 13. hypersensitivity to dextran-40 or dimethyl sulfoxide (dmso) 14. current pharmacotherapy using hydroxychloroquine or interleukin-6 inhibitors 15. history of cva or mi within 180 days of study enrollment

1. unable to understand and provide voluntary informed consent 2. current infection with hiv-1, hiv-2, hepatitis b, hepatitis c or htlv 3. history of malignancy, other than non-melanoma skin cancer or non-metastatic prostate cancer 4. currently receiving extracorporeal life support or high-frequency oscillatory ventilation 5. weight > 150 kg 6. current severe chronic respiratory disease, as demonstrated by: 1. paco2 > 50 mm hg, or 2. history of use of home oxygen 7. major trauma within the past 7 days 8. lung transplant recipient 9. who class iii or iv pulmonary hypertension 10. documented deep vein thrombosis or pulmonary embolism within the past 3 months 11. currently pregnant or lactating 12. currently participating in another clinical trial, or participation in another clinical trial within 30 days of enrollment 13. hypersensitivity to dextran-40 or dimethyl sulfoxide (dmso) 14. current pharmacotherapy using hydroxychloroquine or interleukin-6 inhibitors 15. history of cva or mi within 180 days of study enrollment