inclusion criteria: - patients aged ≥ 18 years - patients (or legally authorized decision maker) must provide informed consent - test positive for sars-cov-2 virus by pcr - admitted to hospital - presence of acute hypoxemia defined as (either or both) - saturation below 93% on ≥ 2 l/min oxygen supplementation - pao2/fio2 below 350

inclusion criteria: - patients aged ≥ 18 years - patients (or legally authorized decision maker) must provide informed consent - test positive for sars-cov-2 virus by pcr - admitted to hospital - presence of acute hypoxemia defined as (either or both) - saturation below 93% on ≥ 2 l/min oxygen supplementation - pao2/fio2 below 350

inclusion criteria: - patients aged ≥ 18 years - test positive for sars-cov-2 virus by pcr - admitted to hospital - presence of acute hypoxemia defined as (either or both) - saturation below 93% on minimal (≥ 2 l/min) oxygen supplementation - pao2/fio2 below 350

inclusion criteria: - patients aged ≥ 18 years - test positive for sars-cov-2 virus by pcr - admitted to hospital - presence of acute hypoxemia defined as (either or both) - saturation below 93% on minimal (≥ 2 l/min) oxygen supplementation - pao2/fio2 below 350