Seen in the ED: Popcorn Kernel

After performing a back blow maneuver on her 10-month-old daughter to dislodge a popcorn kernel, a mother arrives at the ED with the child in distress. What happened?

History of present illness. A 10-month-old girl with no medical history of note is brought to the emergency department for dyspnea after choking on a popcorn kernel. According to the mom, initially the child turned blue and lethargic and so mom quickly performed a back blow maneuver and the child improved significantly but has remained out of breath and inconsolable. Prior to the event the child was in normal health and had no recent illness.

Vital signs and physical examination. Pulse oximeter reading is 90%; the child is tachypneic and crying loudly with possible grunting (hard to tell with all the crying) but breath sounds are symmetric.

Initial diagnostic testing. Chest X-ray

What does the chest x-ray show?