Impact of Early Versus Delayed Intravenous Magnesium Sulfate on Clinical Outcomes in Pediatric Severe Asthma: A Retrospective Cohort Study

Background: Intravenous magnesium sulfate (IV MgSO₄) is a recommended second-line therapy for children with severe asthma exacerbations unresponsive to initial treatment. Although several studies support its efficacy in reducing bronchospasm, the optimal timing of administration in the emergency department (ED) remains unclear. This study aimed to evaluate whether early IV MgSO₄ administration (within 60 minutes of ED arrival) improves clinical and process outcomes in pediatric patients with severe asthma. Methods: This retrospective cohort study was conducted at a tertiary pediatric ED in Riyadh, Saudi Arabia, and included children aged 2–14 years who received IV MgSO₄ for severe asthma between January 2020 and December 2024. Patients were categorized into early (≤ 60 minutes) and late (> 60 minutes) administration groups. Outcomes included time to bronchodilator and corticosteroid administration, Pediatric Respiratory Assessment Measure (PRAM) scores before and after treatment, changes in respiratory support, ED length of stay, hospital admission, pediatric intensive care unit (PICU) transfer, and mortality. Data were analyzed using SPSS version 26. Results: Among 233 patients, 25 (10.7%) received early IV MgSO₄. Compared with the late group, the early group had significantly shorter times to bronchodilator administration (33.4 vs. 70.8 minutes; p < 0.001) and corticosteroid administration (43.2 vs. 90.6 minutes; p < 0.001). They also had lower pre- and post-treatment PRAM scores and reduced ED length of stay (p < 0.05). No significant differences were observed between groups in hospital admission rates, PICU transfers, or mortality. Correlation analysis indicated that earlier MgSO₄ use was associated with greater initial disease severity but improved early clinical response. Conclusion: In pediatric severe asthma, early IV MgSO₄ administration is associated with improved ED process measures and faster symptom resolution but does not significantly influence hospitalization or mortality. These findings support the feasibility and safety of early administration. Larger prospective studies are warranted to determine its effect on long-term outcomes and to inform clinical practice.