[Randomized clinical trial of intravenous magnesium sulfate versus salbutamol in early management of severe acute asthma in children].

OBJECTIVE: To study the efficacy of intravenous magnesium sulfate and intravenous salbutamol in the treatment of severe asthma in children. METHODS: Randomized, double-blind, placebo-controlled clinical trial, including children above 2 years of age with severe acute asthma admitted to the observation ward of the Pediatric Intensive Care Unit of Hospital São Lucas. All patients received conventional treatment (oxygen, corticoids, beta-adrenergics) on admission, and later received one of the following solutions: a) IVMg (50 mg/kg); b) intravenous salbutamol (1 micro g/kg); c) saline solution. Clinical assessments, electrolyte concentration, and arterial blood gas analyses were recorded before intravenous infusion and one hour after that. RESULTS: Fifty patients participated in this study (of whom 53% were females, mean age = 4.5 years). There were no significant differences among the three groups. The group that received IVMg presented lower blood pressure during administration, which reached normal levels one hour afterwards, along with an increase in serum magnesium (P<0,001) and serum pH, and reduction of PaCO(2). The group that received intravenous salbutamol had lower respiratory rate (P=0.05) and higher blood pressure (P=0.01), and one hour after administration, these patients showed decreased respiratory rate (P=0.02); lower levels of serum potassium (P=0.009); higher pH, and reduced PaCO(2). This group required fewer nebulizations (P=0.009), fewer nebulizations per day (P<0.001) and less oxygen therapy than the IVMg and placebo groups. Acidosis was more persistent (P<0.01) in the placebo group. No difference as to the length of hospital stay was observed in any of the three groups. Artificial ventilation was necessary in 10% of the patients. CONCLUSIONS: The early intravenous administration of magnesium sulfate, especially salbutamol, achieved a rapid clinical response with excellent prognosis and no significant side effects.