Table 1.

Flowchart of patient follow-up

			Primary study period		Follow-up
Timepoint	Screening D − 7 to D − 1	Inclusion D − 1 to D0	D1 to D7 after randomization	End of hospitaliztion	D28 after randomization	D90 after randomization	1Y after randomization
Enrollments	×
Eligibility screen	×
Patients information	×
Informed consent	×
Randomization		×
Interventions
HFNC		×	×
Respiratory training		×	×
COT		×	×
Assessments
Baseline variables		×
Laboratory tests Ultrasound, chest radiography		×	×
Primary outcomes			×
Secondary outcomes			×	×
Complication/adverse events			×	×
Alive or dead status				×	×	×	×