Nebulized Magnesium Sulfate as an Adjunct to Standard Therapy in Infants with Acute Bronchiolitis: A Double Blind...

The evidence regarding the efficacy of magnesium sulfate (MgSO₄) in bronchiolitis is conflicting, and high-quality trials involving very young infants are limited. To compare the efficacy of nebulized magnesium sulfate, salbutamol, and 3% hypertonic saline against nebulized salbutamol and 3% hypertonic saline in infants aged 1-6 months who are admitted with a first episode of mild-to-moderate bronchiolitis. The primary outcomes were physiological parameters including oxygen saturation (SpO₂), respiratory rate (RR), and pulse rate (PR). Length of hospital stay (LOS), and Respiratory Distress Assessment Instrument (RDAI) score were evaluated as exploratory outcomes, along with escalation of care and adverse events.

In this parallel, double-blind randomized controlled trial conducted from August 2022 to February 2023, 62 eligible infants were allocated (1:1) to receive three consecutive 20-minute nebulizations of salbutamol, MgSO₄, and 3% saline (intervention) or salbutamol and 3% saline (control), followed by identical doses every 6 hours for up to 72 hours. All caregivers, clinicians, and outcome assessors were blinded. Outcome assessments were performed at baseline (pre-intervention), 1 hour after the initial dose, and every 24 hours thereafter (± 2 hours) until discharge or 72 hours, whichever occurred first. LOS was defined as the duration (in hours) from randomization until predefined discharge criteria were met (SpO₂ ≥ 94% in room air for ≥ 12 hours, adequate oral intake, respiratory rate within age norms, RDAI ≤ 3).

Among the 62 infants, 33 (53.2%) received triple-drug therapy, while 29 (46.8%) received standard dual therapy. The baseline characteristics were comparable, with a mean age as 3.6 ± 1.25 months and 56.5% male. The median Length of stay (LOS) was shorter in the MgSO₄ group (6.0 days, IQR 5-7) compared to the control group (7.0 days, IQR 6-9; P = 0.046, Mann-Whitney U). No significant differences were observed between groups for daily RDAI, RR, PR, or SpO₂ (repeated-measures ANOVA, P > 0.05). None of the infants required intensive care, mechanical ventilation, or experienced serious drug-related events.

This double-blind randomized trial did not demonstrate a statistically significant effect on its prospectively registered primary outcomes (oxygen saturation, respiratory rate, heart rate). The observed difference in length of hospital stay (a secondary, unregistered outcome; median 6.0 vs. 7.0 days; unadjusted P = 0.046) did not reach statistical significance after Bonferroni correction for multiple comparisons (corrected threshold: P < 0.01) and should be regarded as exploratory and hypothesis-generating only. This trial should be interpreted as null and inconclusive. Adequately powered, prospectively registered confirmatory trials are necessary before any clinical recommendations can be made.