Bosso 1988.

Methods	RCT. Parallel design. Duration: last measurement 7 ‐ 14 days after completion of treatment. Single centre. Country: USA.
Participants	30 participants with CF experiencing protocol‐defined pulmonary exacerbation. Age: > 6 years. Intervention 1: 15 participants; mean age 14.1 years; 9 males, 6 females. Intervention 2: 15 participants; mean age 14.7 years; 6 males, 9 females.
Interventions	Intervention 1: IV aztreonam (50 mg/kg 4x daily) for a mean of 17.2 days. Intervention 2: IV azlocillin and IV tobramycin (azlocillin ‐ 350 mg/kg/day in 4 divided doses and tobramycin to reach target serum concentration) for a mean of 14.8 days.
Outcomes	Lung function (FEV1 / FVC), microbiology and adverse effects.
Notes	No sample size calculation.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Described as 'randomly assigned' but no detail given.
Allocation concealment (selection bias)	Unclear risk	No detail given.
Blinding of participants and personnel (performance bias) All outcomes	High risk	Not blinded
Blinding of outcome assessment (detection bias) All outcomes	High risk	Not blinded
Incomplete outcome data (attrition bias) All outcomes	Low risk	None identified.
Selective reporting (reporting bias)	Unclear risk	Insufficient evidence.
Other bias	Low risk	None identified.