Impact of early vs. 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. While its efficacy in reducing bronchospasm is supported by several studies, the optimal timing of administration in the emergency department (ED) remains unclear. This study aimed to evaluate whether early administration of IV MgSO4 (within 60 min of ED arrival) improves clinical and process outcomes in pediatric patients with severe asthma. Methods A retrospective cohort study was conducted at a tertiary pediatric ED in Riyadh, Saudi Arabia, including children aged 2–14 years who received IV MgSO4 for severe asthma between January 2020 and December 2024. Patients were divided into two groups based on the timing of MgSO4 administration: early ( ≤ 60 min) and late (>60 min). The primary outcome for the sample size calculation was PICU admission within 24 h. Outcomes included time to bronchodilator and corticosteroid administration, Pediatric Respiratory Assment 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 v26. Results Among 233 patients, 25 (10.7%) received early IV MgSO4. The early group had significantly shorter times to bronchodilator and corticosteroid administration. Although these patients presented with higher baseline PRAM scores (greater initial severity), they demonstrated greater improvement in PRAM scores after treatment. They also had a shorter ED length of stay ( p < 0.05). No significant differences were observed between groups in terms of hospital admission, PICU transfer, or mortality. Correlation analysis indicated that earlier MgSO4 use was associated with greater initial disease severity but improved early clinical response. Conclusion Early IV MgSO4 administration in pediatric severe asthma is associated with improved ED process measures and symptom resolution but does not significantly affect hospitalization or mortality. These findings support the feasibility and safety of early use. Larger prospective studies are needed to confirm its impact on long-term outcomes and guide clinical practice.