Usefulness of inhaled magnesium sulfate in the coadjuvant management of severe asthma crisis in an emergency department.

RATIONALE: Treatment of severe asthma may be difficult despite the use of several medications including parenteral corticosteroids. Intravenous magnesium sulfate (MgSO(4)) is one ancillary drug for severe crisis; its inhaled use is controversial.

OBJECTIVES: To evaluate the usefulness of inhaled MgSO(4) compared to placebo in improving lung function, oxygen saturation, and reducing hospital admission as an adjunct to standard treatment in severe asthma crisis.

PATIENTS AND METHODS: We conducted a placebo-controlled, double-blind clinical trial with asthmatic patients >18 years of age with asthmatic crisis and FEV(1)<60% of predicted (%p). All subjects received 125 mg of IV methylprednisolone followed by nebulization with the combination of albuterol (7.5mg) and ipratropium bromide (1.5mg) diluted in 3 ml of isotonic saline solution (as placebo) or 3 ml (333 mg) of MgSO(4). After 90 min, subjects with FEV(1)<60%p or SpO(2)<88% or persistent symptoms were admitted to the emergency department (ED).

RESULTS: We included 30 patients per group who were similar at baseline. The MgSO(4) group showed higher post-bronchodilator (post-BD) FEV(1)%p (69+/-13 vs. 61+/-12, p<0.014) and SpO(2) (92+/-4 vs. 88+/-5%, p<0.006) than the placebo group. Fewer treated patients were admitted to the ED (5 vs. 13) (p<0.047), with relative risk (RR) of 0.26 (95% CI 0.079-0.870).

CONCLUSIONS: Adding inhaled MgSO(4) treatment to standard therapy in severe asthma crisis improves FEV(1)%p and SpO(2) post-BD and reduces the rate of ED admissions.