Final answer:
The highest priority action by the nurse when a child presents with inspiratory stridor and a barking cough is to establish and maintain the child's airway, as this ensures the child can breathe adequately and is crucial in managing the emergency situation.
Step-by-step explanation:
When a 2-year-old child presents to the emergency department with inspiratory stridor and a barking cough, the highest priority action by the nurse would be d) Establish and maintain the airway. These symptoms are indicative of a possible upper respiratory obstruction, which could lead to a critical situation if not addressed immediately. Establishing and maintaining an airway ensures that the child can breathe adequately and is the first step in the management of such emergency situations. Additional treatment options after securing the airway could include administering oxygen therapy, performing a throat culture to identify the cause of the symptoms, and placing the child in an appropriate position, which in many cases would be sitting up rather than supine, to aid in easier breathing.