inclusion criteria: * age \> 16 years old * admission to icu * either confirmed positive, or presumed, covid-19 disease * radiological evidence of covid-related pneumonia (cxr or ct abnormalities indicating covid-19 pneumonia; such as, ground-glass opacities) * able to safely undergo conditioning of the arm * no peripheral vascular disease * no evidence of prior arm surgery * no evidence of prior radiation or lymph node dissection * clinical staff deems it safe to proceed (yes/no: signed by mrp)

inclusion criteria: * age \> 16 years old * admission to icu * either confirmed positive, or presumed, covid-19 disease * radiological evidence of covid-related pneumonia (cxr or ct abnormalities indicating covid-19 pneumonia; such as, ground-glass opacities) * able to safely undergo conditioning of the arm * no peripheral vascular disease * no evidence of prior arm surgery * no evidence of prior radiation or lymph node dissection * clinical staff deems it safe to proceed (yes/no: signed by mrp)

inclusion criteria: - age > 16 years old - admission to icu - either confirmed positive, or presumed, covid-19 disease - radiological evidence of covid-related pneumonia (cxr or ct abnormalities indicating covid-19 pneumonia; such as, ground-glass opacities) - able to safely undergo conditioning of the arm - no peripheral vascular disease - no evidence of prior arm surgery - no evidence of prior radiation or lymph node dissection - clinical staff deems it safe to proceed (yes/no: signed by mrp)

inclusion criteria: - age > 16 years old - admission to icu - either confirmed positive, or presumed, covid-19 disease - radiological evidence of covid-related pneumonia (cxr or ct abnormalities indicating covid-19 pneumonia; such as, ground-glass opacities) - able to safely undergo conditioning of the arm - no peripheral vascular disease - no evidence of prior arm surgery - no evidence of prior radiation or lymph node dissection - clinical staff deems it safe to proceed (yes/no: signed by mrp)