Gallegos‐Solórzano 2010.

Methods	RCT, parallel
Participants	Inclusion criteria: adults, >18 years in the emergency dept with asthmatic crisis, FEV1 < 60% predicted. Exclusion criteria: smokers, those with ambulatory use of systemic steroids, with associated co‐morbidities (neuropathy, nephropathy, heart disease, liver disease), fever at admission, use of dietary supplements with MgSO₄, irreversible airway obstruction (persistent abnormal spirometry), near‐fatal asthma, requirement of endotracheal intubation at admission, anatomic abnormalities of the bronchial tree (bronchiectasis, tuberculosis), history of pulmonary or thoracic surgery, hypersensitivity to MgSO₄, and pregnancy or breastfeeding. Location: National Institute of Respiratory Diseases, a tertiary care teaching hospital and national referral centre in Mexico City. Date of study: June 2008 to March 2009. Intervention: 60 randomised, 30 completed. Mean age (years): 34.3 (12.4). Men:women: 9:21. Control: 52 randomised, 30 completed. Mean age (years): 40.3 (11.6). Men:women: 9:21.
Interventions	Each nebulisation lasted 20 mins. Intervention: standard nebulisation but diluted with 3 mL (333 mg) of 10% isotonic MgSO₄ (Magnefusin PISA, Guadalajara, Mexico; 1 g/10 mL). Also received 125 mg of IV methylprednisolone. Control: 1 IV dose of 125 mg methylprednisolone and nebulisation with 7.5 mg of albuterol and 1.5 mg of ipratropium bromide in 3 divided doses. Standard nebulisation diluted in 3 mL of isotonic saline solution (SS) as placebo.
Outcomes	FEV1 post‐BD (absolute in litres and as percentage of predicted), clinical improvement, oxygen saturation, admission to the ED, admission to the asthma ward, hospital readmissions. At 30‐min post‐nebulisation, patients were clinically and functionally re‐evaluated. Also evaluated at 30 days.
Notes	Funding: not reported.
Risk of bias
Bias	Authors' judgement	Support for judgement
Random sequence generation (selection bias)	Unclear risk	Randomised.
Allocation concealment (selection bias)	Low risk	After randomisation, diluents were prepared by a physician outside the study who was not responsible for the participants’ care and only had control of the pre‐filled syringes.
Blinding of participants and personnel (performance bias) All outcomes	Low risk	Double blind. Both diluents are odourless, tasteless and colourless to the eye and did not differ when transparency was measured.
Blinding of outcome assessment (detection bias) All outcomes	Low risk	The physician responsible for the participants’ care along with the nurse and respiratory therapist were blinded to the type of treatment.
Incomplete outcome data (attrition bias) All outcomes	Low risk	Reasons given for dropouts in both groups in the CONSORT diagram.  It seems as though there are a high percentage of dropouts but the majority are post‐randomisation exclusions based on exclusion criteria.
Selective reporting (reporting bias)	Low risk	All outcomes stated in the Methods section are reported.  Best judgement with no access to trial protocol.