Short term effects of adrenaline in bronchiolitis: a randomised controlled trial

Background: Airway narrowing in acute bronchiolitis does not respond to inhaled bronchodilators but does to adrenaline when compared to bronchodilators. Influences of supportive care were not considered in previous treatment studies. Methods: Short term effects of nebulised adrenaline and saline placebo were compared in infants with moderately severe acute bronchiolitis. Thirty eight infants were recruited, 19 in each treatment group. After stabilisation, infants received a single 3 ml dose of either levo-adrenaline (3 mg) or 0.9% saline placebo via Pari-BABY nebuliser driven with 6 l/min oxygen for three minutes. Changes in respiratory rate (RR), heart rate (HR), oxygen saturation (Spo(2)), Respiratory Distress Assessment Instrument (RDAI), and activity levels were assessed at 20 minutes intervals at times -20, 0, 20, 40, and 60 minutes around treatment. Respiratory virology and chest x ray were performed. Results: Supportive therapy prior to study treatment resulted in significant reductions in RR (by 4.3 breaths/min) and HR (by 4.6 beats/min); there were no changes in Spo(2) or RDAI. There were no further changes in any parameter in either treatment group at any assessment time after treatment. Conclusion: No improvement was shown with inhaled adrenaline in acute bronchiolitis, when compared with supportive care or placebo. Improvements noted pretreatment question whether prior noted improvements were through supportive care or pharmacological interventions.