Pulmonary exacerbations and acute declines in lung function in patients with cystic fibrosis

A clinician's decision to diagnose a PEx and treat with antibiotics often is not defined by measured lung function: a ≥10% FEV1 decline is not considered an absolute indication of a PEx and the lack of a decline does not contraindicate a PEx. Clinicians appear to use the history of prior PEx plus other variables as factors for diagnosing PEx.