Table 1

Trial schedule and assessments at different time points

	Study period
Time point	ED arrival	Enrolment	Allocation	Post-intervention							Close-out
Time point	ED arrival	Enrolment	Allocation	1 hour	2 hours	4 hours	12 hours	24 hours	48 hours	72 hours	Close-out
Trial process
Eligibility screen		X
Informed consent		X
Allocation		X
Assessments
Patients’ demographics			X
Temperature	X
Respiratory rate	X		X	X	X	X	X	X	X	X
Blood pressure	X		X	X	X	X	X	X	X	X
Pulse rate	X		X	X	X	X	X	X	X	X
Pulse oximetry	X		X	X	X	X	X	X	X	X
FiO₂			X	X	X	X	X	X	X	X
GCS score			X	X	X	X
Arterial blood gas			X	X
MBS score			X		X	X
Lung ultrasound score			X		X	X
HFNC/NIPPV settings			X	X	X	X
Treatment failure											x
Co-interventions											x
Complications											x
Hospital length of stay											x

FiO₂, fraction of inspired oxygen; GCS, Glasgow Coma Scale; HFNC, high-flow nasal cannula; MBS, modified Borg Scale; NIPPV, non-invasive positive pressure ventilation.