Ballmann 1998.

Study characteristics
Methods	RCT. Design: cross‐over with 2 treatment periods of 3 weeks each and a washout period of 3 weeks in between. Location: Germany.
Participants	Total participants: n = 14, 8 males and 6 females. FEV1 % predicted had to be greater than 40%. Baseline characteristics FEV1 % predicted: mean (SD) 75.6% (14%). Pseudomonas aeruginosa: chronic colonisation: n = 9; free: n = 3; intermittent: n = 2.
Interventions	Pre‐treated salbutamol 200 mcg MDI inhaled (2 puffs). Group 1: 10 mL HS 5.85% 2x daily. Group 2: 2 mL Pulmozyme 2.5 mg 2x daily. Treatment was given via a Pari Master with Pari LL Routine medication not altered during trial.
Outcomes	Change in FEV1 as a % of predicted, nebulisation time, comparison of cost (in Deutschmarks), preference.
Notes	There was a 3‐week washout between interventions. No sample size calculation stated.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Low risk	Participants randomised into groups of 4 and drew lots to start with HS or rhDNase.
Allocation concealment (selection bias)	Unclear risk	No details provided as to how lots concealed allocation.
Blinding of participants and personnel (performance bias) All outcomes	High risk	Taste of HS and difference in volume made blinding not possible.
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Not discussed.
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	No information provided whether an ITT was used.
Selective reporting (reporting bias)	Low risk	All outcomes stated in the 'Methods' section reported in the 'Results' section.
Other bias	Low risk	Washout period of 3 weeks. No sample size calculation stated.