Rittayamai 2014.

Study characteristics
Methods	RCT, cross‐over design. Single‐centre
Participants	Total number of randomized participants: 17 Setting: respiratory ICU; Bangkok, Thailand Inclusion criteria: mechanically ventilated patients who were 18 years of age, successfully weaned by spontaneous breathing, trial with oxygen T‐piece or low level of pressure support for 120 minutes, and ready for endotracheal extubation Exclusion criteria: haemodynamic instability or decreased level of consciousness; patients who lacked co‐operation, tracheotomized patients, and pregnant women Baseline characteristics: Age, mean (SD): 66.8 (± 13.8) years Gender, M/F: 10/7 BMI, mean (SD): not reported SAPS II, mean (SD): 30.9 (± 4.4) Respiratory rate, mean (SD): recorded before each cross‐over period: baseline 1: 20.3 (± 4.5); baseline 2: 21.7 (± 3.8) breaths/min PaCO2: not reported PaO2/FiO2: not reported
Interventions	Intervention group (HFNC): Details: HFNC, Optiflow system, Fisher & Paykel Healthcare; initial inspiratory flow of 35 L/min, and FiO2 adjusted to achieve SpO2 ≥ 94% within the first 5 minutes and to maintain this setting for 30 minutes Control group (standard oxygen therapy): Details: Non‐rebreather face mask, 6 to 10 L/min to achieve SpO2 94% for another 30 minutes
Outcomes	Dyspnoea, patient comfort, breathing frequency, heart rate blood pressure, SpO2
Notes	Funding/declarations of interest: study authors did not report funding sources. They disclosed no conflicts of interest. Study dates: August to December 2011
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Methods used to generate group allocation not stated
Allocation concealment (selection bias)	Unclear risk	Methods of allocation concealment not stated
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Blinding was not possible. Although we expected that this would not influence outcome data, we could not be certain of this.
Blinding of outcome assessors (objective outcomes)	Low risk	Unable to blind outcome assessors owing to nature of the intervention: we did not anticipate that this would influence the assessment of objective outcome measures.
Blinding of outcome assessors (subjective measures)	Low risk	Unable to blind outcome assessors owing to nature of the intervention. Participants were outcome assessors for comfort: We did not expect that this would influence the outcome data.
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	No statement of how many reported. No participant numbers in tables or graphs
Selective reporting (reporting bias)	Unclear risk	Trial registration not reported in paper. Unable to establish whether outcomes were reported according to pre‐published protocol or trial registration documents SpO2 and mean arterial pressure not reported for all time points set out in methods
Other bias	Low risk	We identified no other risks of bias.