Question

A 30-month-old male child is evaluated in the pediatric pulmonology clinic for a persistent cough and recurrent lower respiratory tract infections. Over the previous 8 months, he has had three distinct episodes of right lower lobe pneumonia diagnosed at a local urgent care facility. Each episode presented with tachypnea and fever, and partially improved following a 7-day course of oral amoxicillin-clavulanate. His caregivers note that between these infectious episodes, he exhibits a dry, hacking cough and frequently makes a faint "whistling" noise when exhaling. They do not recall any specific choking events prior to the onset of these symptoms. The child has no history of atopic dermatitis, and his weight is at the 60th percentile for his age. Today, he appears comfortable and is afebrile with a respiratory rate of 24/min. Pulmonary auscultation reveals diminished breath sounds and a monophonic wheeze localized exclusively to the right posterior lung base. The remainder of the physical examination is unremarkable. Bilateral lateral decubitus chest radiographs are obtained; the right lung volume remains fully expanded when the patient is placed in the right lateral decubitus position, whereas the left lung volume appropriately decreases in the left lateral decubitus position. Which of the following is the most appropriate next step in the management of this patient?