inclusion criteria: * suspected or confirmed covid-19 * aged ≥14 years old at the participating icu. icus that use other age cut-off for adult patients will adhere to their local standard (16 or 18 years) * acute hypoxemic respiratory failure based on pao2/fio2 ratio \<200 despite supplemental oxygen with a partial or non-rebreathing mask at a flow rate \>10 l/min or above * intact airway protective gag reflex * able to follow instructions (e.g. squeeze hand on command, eye contact with care provider, stick out tongue on command, etc.)

inclusion criteria: * suspected or confirmed covid-19 * aged ≥14 years old at the participating icu. icus that use other age cut-off for adult patients will adhere to their local standard (16 or 18 years) * acute hypoxemic respiratory failure based on pao2/fio2 ratio \<200 despite supplemental oxygen with a partial or non-rebreathing mask at a flow rate \>10 l/min or above * intact airway protective gag reflex * able to follow instructions (e.g. squeeze hand on command, eye contact with care provider, stick out tongue on command, etc.)

inclusion criteria: - suspected or confirmed covid-19 - aged ≥14 years old at the participating icu. icus that use other age cut-off for adult patients will adhere to their local standard (16 or 18 years) - acute hypoxemic respiratory failure based on pao2/fio2 ratio <200 despite supplemental oxygen with a partial or non-rebreathing mask at a flow rate >10 l/min or above - intact airway protective gag reflex - able to follow instructions (e.g. squeeze hand on command, eye contact with care provider, stick out tongue on command, etc.)

inclusion criteria: - suspected or confirmed covid-19 - aged ≥14 years old at the participating icu. icus that use other age cut-off for adult patients will adhere to their local standard (16 or 18 years) - acute hypoxemic respiratory failure based on pao2/fio2 ratio <200 despite supplemental oxygen with a partial or non-rebreathing mask at a flow rate >10 l/min or above - intact airway protective gag reflex - able to follow instructions (e.g. squeeze hand on command, eye contact with care provider, stick out tongue on command, etc.)

inclusion criteria: - suspected or confirmed covid-19 - aged ≥ 14 years old at the participating icu. icus that use other age cut-off for adult patients will adhere to their local standard (16 or 18 years) - a respiratory rate > 25 breaths/ minute - acute hypoxemic respiratory failure (pao2/fio2 ratio < 200) evaluated during oxygen therapy supplied for at least 15 minutes at an fio2 (fraction of inspired oxygen inspired oxygen fraction) of at least 0.50 - intact airway protective gag reflex - able to follow instructions (e.g. squeeze hand on command, eye contact with care provider, stick out tongue on command,etc.)

inclusion criteria: - suspected or confirmed covid-19 - aged ≥ 14 years old at the participating icu. icus that use other age cut-off for adult patients will adhere to their local standard (16 or 18 years) - a respiratory rate > 25 breaths/ minute - acute hypoxemic respiratory failure (pao2/fio2 ratio < 200) evaluated during oxygen therapy supplied for at least 15 minutes at an fio2 (fraction of inspired oxygen inspired oxygen fraction) of at least 0.50 - intact airway protective gag reflex - able to follow instructions (e.g. squeeze hand on command, eye contact with care provider, stick out tongue on command,etc.)