Pilot Observational Study to Determine Feasibility of a Standardized Treatment of Pulmonary Exacerb. in Patients With CF

Inclusion Criteria: * Male or female ≥12 years of age at Visit 1 * Enrolled in the CFFNPR (Patients may enroll in the Registry at Visit 1 if not previously enrolled.) * Current hospitalization for treatment of a pulmonary exacerbation * Planned hospital admission of at least 5 days with intravenous (IV) antibiotics at Visit 1 * Able to perform spirometry at admission and willing to perform spirometry on subsequent treatment and visit days * Willing and able to complete symptom score daily * Willing to return for a follow up visit at end of treatment (if necessary) and 28 days after start of IV antibiotic therapy * Written informed consent (and assent when applicable) obtained from the participant or participant's legal representative Exclusion Criteria: * Previous enrollment in this study * Treatment with IV antibiotics in the 6 weeks prior to Visit 1 * Admission to the intensive care unit for current pulmonary exacerbation * Pneumothorax on admission * Current hospitalization for scheduled pulmonary clean out * Current hospitalization for sinusitis as the primary diagnosis * Massive hemoptysis defined as \> 250 cc in a 24 hour period, or 100 cc/day over 4 consecutive days occurring within one week of Visit 1 * Current pulmonary exacerbation thought to be due to allergic bronchopulmonary aspergillosis (ABPA) * Ongoing treatment with prednisone equivalent \>10 mg/day for greater than 2 weeks initiated prior to Visit 1 * History of solid organ transplantation Currently receiving antimicrobial therapy to treat non-tuberculous mycobacterium (e.g., M. abscessus, M. avium complex)