Husby 1993.

Methods	Randomised double‐blind controlled trial
Participants	Study period: October 1990 to December 1991 Setting: Department of Paediatrics, Kolding Hospital, Denmark Inclusion criteria: children admitted to hospital with croup (inspiratory stridor, cough, and respiratory distress), with a modified Westley croup score > 5 and informed parental consent Exclusion criteria: clinical condition consistent with epiglottitis, foreign body aspiration, bronchiolitis, or asthma; received local or systemic steroid treatment or epinephrine Baseline demographics (N = 36) (1 child excluded before placebo was administered): proportion male: treatment: 80%; control: 75% median (range) age in years: treatment: 1.6 (0.6 to 4.9); control: 1.1 (0.4 to 4.2) median (range) modified Westley croup score: treatment: 8 (6 to 10); control: 8 (6 to 12)
Interventions	Treatment (N = 20): 2, 1000 µg (2 mL 500 µg/mL) doses of nebulised budesonide, 30 minutes apart Control (N = 16): 2, 2 mL doses of placebo (0.9% saline), 30 minutes apart Both treatment and placebo were given with a dynamic flow rate of 8 L/min.
Outcomes	Change in modified Westley croup score from baseline to 2 hours; use of antibiotics
Notes	Funding source: not reported
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Comment: insufficient information provided to judge.
Allocation concealment (selection bias)	Unclear risk	Comment: insufficient information provided to judge.
Blinding of participants and personnel (performance bias) All outcomes	Unclear risk	Comment: described as double‐blind, no further explanation. Insufficient information provided to judge.
Blinding of outcome assessment (detection bias) All outcomes	Unclear risk	Comment: no description of a third‐party outcome assessor. Carried over judgement from blinding of participants and personnel
Incomplete outcome data (attrition bias) All outcomes	Low risk	Comment: 1 child omitted as did not receive treatment due to technical problems. No other missing outcome data
Selective reporting (reporting bias)	Unclear risk	Comment: no protocol identified. All prespecified outcomes from methods appear in results.
Other bias	Low risk	Comment: no other sources of bias identified.
Overall risk of bias All outcomes	Unclear risk	Comment: at least 1 domain judged as unclear risk, and no domains judged as high risk.