Khan 2014.

Study characteristics
Methods	RCT. Parallel design. Location: single centre in Russia. Duration: 10 'procedures' (not clear how many procedures per day).
Participants	30 children aged 5 ‐ 17 years.
Interventions	HFCWO versus control (control not mentioned so alternative ACT unknown, assumed that 15 participants were randomised to each treatment group).
Outcomes	FEV1, FVC, exercise tolerance, sputum volume and SpO₂ But as we are unaware of the alternative "control" ACT we cannot include the data in the meta‐analysis.
Notes	Only abstract in English, therefore translation required but even following translation the paper had limited quality and limited information as to the actual interventions and their frequency.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Stratified randomisation declared, not described.
Allocation concealment (selection bias)	Unclear risk	Not mentioned.
Blinding (performance bias and detection bias) All outcomes	Unclear risk	Not mentioned.
Incomplete outcome data (attrition bias) All outcomes	Low risk	No drop outs. All 30 data sets included in their analysis
Selective reporting (reporting bias)	Unclear risk	No objective data on sputum volume, although it was stated there was an improvement following the intervention.
Other bias	Unclear risk	Not clear as abstract only in English and no clear evidence of excluded bias in translated paper.