Abstract
OBJECTIVE: Our objective was to compare doses of intravenous magnesium sulfate and their association with escalations in therapy in children and adolescents presenting to the emergency department with an asthma exacerbation. METHODS: This was a retrospective cohort study among children who received both magnesium sulfate and standard of care therapy for asthma exacerbations. A classification and regression tree (CART) analysis was performed to identify a breakpoint in dose in which a difference in the primary outcome was present. The primary endpoint was need for escalation in therapy within 24 hours of initial magnesium sulfate dose, defined as need for invasive or non-invasive mechanical ventilation or need for adjunctive therapy, that is, epinephrine, terbutaline, aminophylline, theophylline, ketamine, heliox, or additional doses of magnesium sulfate. RESULTS: A total of 210 patients were included in the study. A CART analysis identified that a breakpoint of 27 mg/kg of magnesium was associated with a difference in the primary outcome of escalation in therapy in patients <40 kg. A subgroup analysis of patients <40 kg (n = 149) found patients who received magnesium doses >27 mg/kg had a higher incidence of the primary outcome of escalation in therapy, 15 patients (18.3%) versus 3 patients (4.5%) in the ≤27-mg/kg/dose group (p = 0.011). CONCLUSIONS: Our results demonstrate larger doses of magnesium sulfate are associated with an increased need for invasive or non-invasive mechanical ventilation or need for adjunctive therapy(ies). Our findings are limited by confounding factors that may have influenced this outcome in our population.