Final answer:
The nurse's priority when caring for a child with cystic fibrosis and a pulmonary infection is managing increased respiratory effort and decreased oxygen saturation, as these symptoms can pose an immediate threat to the child's life.
Step-by-step explanation:
The priority finding for a nurse caring for a child with cystic fibrosis and a pulmonary infection would be D. Increased respiratory effort and decreased oxygen saturation. Cystic fibrosis leads to the production of thick, sticky mucus in the lungs, which hampers the body's defenses and provides an environment for bacteria like Pseudomonas aeruginosa to thrive and form biofilms, leading to further lung damage. With such infections, a patient may experience increased respiratory effort as the body works harder to obtain oxygen and decreased oxygen saturation due to impaired gas exchange. Managing the patient's airway and breathing is paramount, as respiratory failure can be a direct threat to life.
Instances like a decreased respiratory rate would be concerning, but it is not as immediately threatening as increased effort and diminished oxygen saturation, which indicate the child is currently struggling to breathe adequately. A decreased white blood cell count may suggest an impaired immune response, and while elevated blood glucose levels may be part of the clinical picture in cystic fibrosis, they are not the most pressing issue when facing an acute pulmonary infection.