Kluft 1996.

Study characteristics
Methods	Quasi‐RCT (alternate allocation). Cross‐over design. Location: single centre in USA. Duration: 8 days (treatments alternating daily for 4 days).
Participants	29 participants (15 males, 14 females). Age range 7 ‐ 47 years. Diagnosis of CF and clinical evidence of chronic disease.
Interventions	3x daily 30 min CPT/PD versus 3x daily 30 min HFCWO. Participants continued to receive their standard bronchodilators prior to therapies.
Outcomes	Sputum weight (wet and dry). Each participant provided 3 samples per day for 4 days and all 12 samples were used to calculate the means and standard deviations.
Notes	1 individual not enrolled due to intolerance of HFCWO, although had met the inclusion criteria ‐ never really entered the study therefore not really a drop out.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Initially randomly assigned, but method not stated then treatment assignments alternating daily.
Allocation concealment (selection bias)	High risk	Alternate.
Blinding (performance bias and detection bias) All outcomes	Unclear risk	Not discussed.
Incomplete outcome data (attrition bias) All outcomes	Low risk	1 individual not enrolled due to intolerance of HFCWO, although had met the inclusion criteria ‐ never really entered the trial therefore not really a drop out.
Selective reporting (reporting bias)	Low risk	Potential adverse effects were identified but none occurred.
Other bias	Unclear risk	Not discussed.