A 2-mоnth-оld infаnt presents tо the emergency room with а low-grаde fever, rhinorrhea, wheezing, and a history of difficulty feeding for the past 48 hours. The following data are available: SpO2: 88% breathing air RR: 65 breaths/min HR: 122 beats/min, no murmur or clicks Mild intercostal retractions are noted, Breath sounds: Scattered wheezing. Lung fields well aerated. Which of the following physiologic conditions should the respiratory therapist suspect the hypoxemia resulted from?