inclusion criteria: * adults \> 18 years. * emergency or icu admission with suspected/confirmed sars-cov-2 infection. * moderate/severe acute respiratory failure: * pao2/fio2 \< 200. * use of accessory muscles. * breathing rate \> 25 x minute. * have a progression \< 6 hours since meeting the definition of moderate/severe acute respiratory failure secondary to suspected/confirmed sars-cov-2 infection.

inclusion criteria: * adults \> 18 years. * emergency or icu admission with suspected/confirmed sars-cov-2 infection. * moderate/severe acute respiratory failure: * pao2/fio2 \< 200. * use of accessory muscles. * breathing rate \> 25 x minute. * have a progression \< 6 hours since meeting the definition of moderate/severe acute respiratory failure secondary to suspected/confirmed sars-cov-2 infection.

inclusion criteria: - adults > 18 years. - emergency or icu admission with suspected/confirmed sars-cov-2 infection. - moderate/severe acute respiratory failure: - pao2/fio2 < 200. - use of accessory muscles. - breathing rate > 25 x minute. - have a progression < 6 hours since meeting the definition of moderate/severe acute respiratory failure secondary to suspected/confirmed sars-cov-2 infection.

inclusion criteria: - adults > 18 years. - emergency or icu admission with suspected/confirmed sars-cov-2 infection. - moderate/severe acute respiratory failure: - pao2/fio2 < 200. - use of accessory muscles. - breathing rate > 25 x minute. - have a progression < 6 hours since meeting the definition of moderate/severe acute respiratory failure secondary to suspected/confirmed sars-cov-2 infection.