After a 4-h observation period, the treating clinician determined patient disposition. If admitted, the patient continued to receive aerosols containing the same designated medication every 6 h until discharge or 24 h after the admission. Bronchiolitis severity scores were obtained before and after each treatment. A standardized data sheet was completed after enrollment and during each patient's stay in the ED or inpatient ward. Any co-interventions such as additional bronchodilators, supplemental oxygen, intravenous fluids, or deep nasal suction were at the discretion of the treating clinician. The clinician was free to withdraw the patient from the study if clinical deterioration warranted escalation of care or if adverse effects related to the medication were observed.