Final answer:
The nurse wrote the nursing diagnosis: Impaired gas exchange related to alveolar-capillary membrane changes.
Step-by-step explanation:
The nurse wrote the nursing diagnosis of Impaired gas exchange related to alveolar-capillary membrane changes. Pneumonia is an inflammatory disease of the respiratory tract that affects the alveoli in the lungs, leading to fluid buildup and hindered gas exchange. The chest x-ray results of lower lobe infiltrates indicate alveolar-capillary membrane changes, which directly affect gas exchange. Therefore, the nursing diagnosis of impaired gas exchange is appropriate for this patient.