You have been dispatched to a home for a 16-year-old female with shortness of breath. On scene you find the patient in bed with her mother at her side. Her mother states that her daughter has a fever with a past medical history of cystic fibrosis and would like to have her transported to the hospital for evaluation of possible pneumonia. As a knowledgeable EMT, you know that the underlying pathophysiology of cystic fibrosis is a ____________