The degree of improvement in FEV1 defined as absolute difference between admission FEV1 and discharge FEV1 will be used as primary outcome measure to compare effectiveness between both modalities. This measure is commonly used in the Cystic Fibrosis community of clinicians and researchers as measure of airway obstruction and disease severity. We will perform spirometry at least twice, at admission and discharge, on these patients. The patient's spirometry from their office visit on the same day of admission or first spirometry during their admission will count as the initial spirometry. Last spirometry obtained before discharge will be the discharge spirometry. Additional spirometry may be performed during the patient's admission at the attending provider's clinical discretion. We will also use data from these additional spirometry measurements if they take place.