Arens 1994

Methods	RCT. Parallel design. Location: single centre in USA. Duration: 2 weeks, follow up not stated.
Participants	50 (32 males, 18 females) participants randomised. Age range 16.9 ‐ 24.9 years. Participants with CF and an acute exacerbation who had been admitted to hospital.
Interventions	HFCWO for 30 min 3x daily in sitting whilst receiving nebuliser. CPT 30 min 3x daily in 6 different PD positions, following 15 min of nebuliser. 25 participants randomised to each treatment group. Treatment 2 weeks in duration.
Outcomes	Respiratory function (VC, FEV₁, FEF and RV), sputum weight in g both wet and dry at 1 hour and 24 hours. Participants reported satisfaction with technique and % change in Sa0₂. Outcome measurements taken at admission, 7 days and 14 days.
Notes
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Not reported how sequence was generated.
Allocation concealment (selection bias)	Unclear risk	Not reported.
Blinding (performance bias and detection bias) All outcomes	High risk	No blinding of assessors or participants.
Incomplete outcome data (attrition bias) All outcomes	Low risk	4 dropouts were identified and this was due to failure to comply with the therapy regimen.
Selective reporting (reporting bias)	Unclear risk	Not possible to compare original trial protocol with final paper.
Other bias	Unclear risk	None identified.