Tonnesen 1982.

Study characteristics
Methods	Single‐centre (The National Hospital of Copenhagen, Denmark), cross‐over RCT. 15 participants with CF randomly allocated to either CCPT or PEP, each to be carried out for 4 weeks. Unclear whether washout period between
Participants	15 participants with CF. Means of CF diagnosis not specified. 12 had chronic Pseudomonas aeruginosa infection Age range 12–29 years 6 male, 9 female
Interventions	PEP breathing mask with a rectifier valve and tracheal tube connection: applied in sitting position, with an expiratory resistance "chosen according to the patient's tolerance" (mean initial resistance 3.9 (SD 0.3) decreased to 3.6 (SD 0.3) at 14 days). PEP delivered via a mask, at home, for 15 min (with 2‐ to 3‐min breaks), 3 times daily for 1 month CCPT: 1–3 times per day given by "the usual therapist" (a mix of participant's mother, father and physiotherapist), with 20–30 min "consisting of vibrations, tapotement, expansion exercises, and standing drainage on a specialized, tilt‐able bed."
Outcomes	Peak flow, FVC, FEV1, RV, FRC, TLC were obtained at baseline and after 1 month of either PEP or CCPT. Sputum samples taken (unclear at which time points – 24 samples from 14 participants). 12/14 participants had CXR at baseline and 1 month after treatment. The other 2 had "completely normal chest radiographs and were not checked after the treatments." A multifaceted disease severity scoring system was applied where points were assigned on the basis of weight and height, physical activity, presence of clubbed fingers, CXR and CF complications: 1 being very severe and 10 being unaffected. The cohort mean was 5.9.
Notes	Data extraction with assistance from Dr Connor Brenna, Department of Anesthesiology & Pain Medicine in the University of Toronto, Toronto, ON, Canada.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Method of randomisation was not specified, but the paper stated that 15 participants were assigned to therapy on the basis of a randomised cross‐over design.
Allocation concealment (selection bias)	Unclear risk	Not described in the paper.
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Not feasible (participants), not described (personnel).
Blinding of outcome assessment (detection bias) All outcomes	Low risk	The radiologist assessing paired CXRs for each participant was blind to treatment group.
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	15 participants recruited, 1 withdrew (and was not included in the analysis). The paper described a participant (14F) who withdrew 2 days into PEP treatment "due to a feeling of secretion stagnation in the lungs," when she and her mother became sceptical about the PEP treatment and felt that CCPT was necessary. The paper noted that the participant "later began mask treatment and postural drainage with apparently good effect."
Selective reporting (reporting bias)	Unclear risk	Paper reported that every 14 days, the outpatient check‐ups included lung function examination, sputum culture for bacteria, clinical examination and instructions regarding how to use the mask. However, only data at beginning and end of each month were reported.
Other bias	Unclear risk	Potentially the fact that CCPT and PEP were carried out for different durations (15 min with PEP vs 20–30 min with CCPT) and at different frequencies (3 times per day with PEP vs 1–3 times per day with CCPT). Authors described a clinical score where "1 point represents a patient in extremely poor condition and 10 points a completely unaffected patient." Yet they suggest the range in the participant group was 0–9, with mean score of 5.9.