Table 1

Timing of assessments

Time	Screening	1 hour*	6 hours*	24 hours*	24 hours*† (till discharge)
Inclusion criteria	*
Exclusion criteria	*
Informed consent	*
Demographics/medical history	*
Arterial blood gas (ABG*)	*	*	*	*	*
NIV rate		*	*	*	*
Intubation rate		*	*	*	*
Dyspnoea score	*	*	*	*	*
Comfort score		*
Physiological variables	*	*	*	*	*
Adverse event assessment		*	*	*	*

*Or the nearest time-point when ABG is available. Any additional available ABG result will also be collected and imputed to the nearest hourly time-point. Additional blood sampling will be avoided to reduce patient discomfort.
†The 24 hours variables will be collected till death or discharge, whichever is earlier. ABG will be collected where available.
NIV, non-invasive ventilation.