Subjects randomized to the aerosol surfactant evaluation will occur at the end of 60 minutes, with the aerosol continued if the bronchiolitis score is > 4 or there has been less than a 2-point improvement in the bronchiolitis score. Similar evaluation will be performed, if necessary, at 30-minute intervals (maximum 2 hours) with stoppage of the aerosol for an improved bronchiolitis score (≤ 4 or 2-point improvement) at any of the time points. The aerosol would be stopped at any time for significant sustained deterioration in clinical status or any serious adverse event felt related to the treatment. Retreatment can be given at > 4 but < 24 hours if the initial response was positive and there has been subsequent deterioration.

The only difference in care between treatment and usual care will be treatment with up to two doses of aerosolized Infasurf®.

Infants randomized to aerosol treatment will receive Infasurf® aerosol at a rate of 12 ml/hour (the maximal rate using the Solaris CAG). The initial treatment will be for 60 minutes, with reevaluation every 30 minutes thereafter, with a maximum dose of 6 mL/Kg body weight or 2 hours of aerosolization. Treatment will be stopped after 60 minutes (and subsequently at 30-minute intervals) if a 2 point reduction in bronchiolitis score or a score ≤ 4 is achieved. Treatment will also be stopped at any time should there be evidence of other-than-transient deterioration in oxygenation or clinical status or for any serious adverse effect deemed by the infant's clinician to be possibly related to the drug administration.

Incidence of positive respiratory response to Infasurf® Aerosol defined as Bronchiolitis Clinical Score decreased by 2 points or to ≤4.

Incidence of need for non-invasive (BiPAP, NIV-NAVA) or invasive ventilation

To determine the optimal dose/duration of aerosolized Infasurf® in infants with bronchiolitis by aerosolizing Infasurf at 35mg/ml at a rate of 1.8 to 2.2 mls per minute until therapeutic response is achieved or the maximum amount of a single dose is reached.