Khashabi 2008.

Methods	Parallel RCT.
Participants	Location: authors based in Iran. Participants: 40 asthmatic children in total between 2 groups. Mean age: 3.55 years.
Interventions	Intervention: nebulised salbutamol, as a vehicle isotonic MgSO₄ mixed with salbutamol. Control: nebulised salbutamol, as a vehicle 2.5 mL of normal saline.
Outcomes	Days of hospital stay, hours of need for oxygen, respiratory distress. Measured 1 h before and 1 h after the second course of treatment.
Notes	Abstract only. Funding: not reported.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Randomly enrolled.
Allocation concealment (selection bias)	Unclear risk	Not stated.
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Double blind.
Blinding of outcome assessment (detection bias) All outcomes	Low risk	Double blind.
Incomplete outcome data (attrition bias) All outcomes	Unclear risk	Not stated.
Selective reporting (reporting bias)	Low risk	Outcomes stated as measured, reported. Abstract only.