Lagerkvist 2006.

Methods	RCT. Cross‐over design. Single treatment.
Participants	15 people with CF, 6 females, 9 males, age 6.9 to 21.5 years. CF confirmed by sweat test.
Interventions	2 interventions: 8‐week washout period between interventions 1. PEPusing Astra Tech system with mouthpiece pressures 10 ‐ 20cm H₂O ‐ participant breathed through the device for 2 minutes followed by huffing; this was repeated 4 times; 2. Oscillating PEP using the flutter ‐ participants were instructed to inhale deeply then exhale quickly through the device and repeat for 1 minute followed by huffing; this was repeated 4 times.
Outcomes	PFTs consisting of FVC, FEV1, MEF50 and MEF 25 all of 5 predicted. Pt02, Ptco2.
Notes	Published paper.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	No mention of how the participants were randomised.
Allocation concealment (selection bias)	Unclear risk	No mention of how the allocation was concealed.
Blinding (performance bias and detection bias) All outcomes	Unclear risk	Not discussed.
Incomplete outcome data (attrition bias) All outcomes	Low risk	All outcomes in study design are reported.
Selective reporting (reporting bias)	Low risk	All outcomes are reported in full.
Other bias	Low risk	Good washout period, thus low risk of carry over effect. Groups similar at baseline regarding the most important prognostic indicators. No dropouts.