Final answer:
The PN would suspect that the toddler has choked on a foreign object and is experiencing airway obstruction.
Step-by-step explanation:
The sudden onset of stridor, difficulty breathing, and the fact that the child was playing with an old shirt suggest that the toddler may have choked on a foreign object. When a foreign object gets lodged in the airway, it can partially or completely block the flow of air, resulting in stridor (a high-pitched sound during breathing). It is essential to seek medical attention immediately to remove the obstruction and ensure proper breathing.