Documented Covid-19 positive Evidence of progressive clinical decline: o Rising inflammatory markers over a 24 hour period (increases in CRP, d-dimer, LDH and/or ferritin above the upper limit of normal) o Presence of or progression of pulmonary infiltrates on CXR (as decided by the treating physician) o New hypoxia requiring >2l/min/28% FiO2 to maintain oxygen saturations ≥94% (or 88-92% in patients with chronic hypercapnic respiratory failure)

Documented Covid-19 positive Evidence of progressive clinical decline: o Rising inflammatory markers over a 24 hour period (increases in CRP, d-dimer, LDH and/or ferritin above the upper limit of normal) o Presence of or progression of pulmonary infiltrates on CXR (as decided by the treating physician) o New hypoxia requiring >2l/min/28% FiO2 to maintain oxygen saturations ≥94% (or 88-92% in patients with chronic hypercapnic respiratory failure)