VL is a 15-year-old white male with cystic fibrosis. This disease has affected both his lungs and his pancreas. The mucus secreted by the epithelial cells of the airways and the exocrine pancreas is abnormally thick and tends to precipitate, forming dense plugs that obstruct bronchi, bronchioles, pancreatic ducts, and bile ducts. Experiencing a fever and an acute exacerbation of his pulmonary symptoms, including dyspnea, rales, and rhonchi, VL went to his doctor. The physician made the