Bradley 1978.

Methods	Blinding: single; Randomisation: no description; Withdrawals: none; Baseline characteristics: comparable; Point/ variability estimates for between group analysis: yes Power calculation: none Jadad=1/5 Pedro=7/10 Statistical analysis: Student's paired t test
Participants	Country USA; N=26; 11M; 64.7 (8.7) years; FEV1 22.2 (7.8)%; FVC 47.9 (14)%; SaO2 92 (4.1)%; **PaO2 69 (14.3)mmHg; PaCO2 41.8 (8.1) mmHg;
Interventions	5 L/min O2 or air via cylinder and nasal specs
Outcomes	see table‐ outcome measures used
Notes	No contact address
Risk of bias
Bias	Authors' judgement	Support for judgement
Allocation concealment?	Unclear risk	Information not available (Cochrane Grade B)