 Patients will then receive, in a randomized double-blinded fashion, levalbuterol, 1.25mg every 20 minutes for a total of 3 aerosolized doses combined with ipratropium, 0.5mg every 20 minutes for a total of 3 aerosolized doses. The medication will be premixed by the pharmacy in a total of 3 ml of normal saline and the nebulizer will be driven with oxygen at 6 liters per minute. A second plasma sample for analysis of albuterol isomers will be drawn within a fifteen minute window following the third aerosol treatment. Spirometry will be repeated again at 30 and 60 minutes after the third aerosol treatment Figure 1. All patients will receive prednisone, 60mg orally immediately after their first dose of aerosolized medications, unless contraindications to prednisone administration are present. Patients will not receive any other medications during the time course of the study. Vital signs and pulse oximetry will be repeated prior to each nebulized treatment and again 30 minutes after the third nebulized treatment. 