Specific Aim 2: The frequency of B lines, subpleural consolidations, and pleural effusions on lung US in a convenience sample of patients 0-24 months presenting the ED with wheezing will be quantified using continuous variable means and standard deviations. An exploratory analysis will be performed to look for correlations between lung US findings and clinical outcomes including discharge from the ED or admission to the hospital, including the intensive care unit, and length of stay in the ED. A further exploratory analysis will be done to look for correlations between lung ultrasound findings and acute severity, final diagnosis, presenting symptoms, prematurity and risk factors for atopy.