Clinical scenario

A known asthmatic patient is brought into the emergency department with signs consistent with acute asthma. Little improvement is noted with nebulised β agonist therapy. You wonder if adjunctive nebulised magnesium sulphate would provide any benefit.

Three part question

In [an adult with asthma] is [nebulised β agonist with nebulised magnesium sulphate better than nebulsed β agonist alone] at [improving airflow and reducing morbidity]?

Search strategy

Medline 1966-05/04 using the Ovid interface. [(Exp magnesium OR magnesium$.mp OR exp magnesium sulfate OR magnesium sul$.mp OR exp magnesium compounds OR magnesium compound$.mp) AND (nebulise$.mp OR nebulize$.mp OR vaporise$.mp OR vaporize$.mp OR inhal$.mp) AND (Exp asthma OR asthma$.mp OR exp bronchial spasm OR bronchial spasm.mp OR bronchospasm.mp)] Limit to human AND English language.

Search outcome

Altogether 69 articles found of which five were relevant to the original question (see table 1).

Comment(s)

Extensive evidence exists regarding efficacy of intravenous magnesium in bronchospasm reversal. Of the few studies that relate to nebulised magnesium in bronchospasm reversal, samples remain small and conflicting results regarding optimal dose magnesium and sole agent efficacy persist. It is empirically suggested such mode of magnesium delivery be considered in cases of severe asthma only.

CLINICAL BOTTOM LINE

There is currently insufficient evidence to support the routine addition of nebulised magnesium to standard β agonist therapy in acute asthma exacerbation.