A nurse is caring for a toddler who has acute laryngotracheobronchitis and has been placed in a cool mist tent. Which of the following finding indicates that the treatment has been effective?

The correct answer is B: Decreased stridor. Stridor is a high-pitched, harsh sound during breathing caused by airway obstruction. In acute laryngotracheobronchitis, the airway is inflamed, leading to stridor. Placing the toddler in a cool mist tent helps reduce inflammation and opens the airway, resulting in decreased stridor. Barking cough (choice A) is a symptom of croup, not an indicator of treatment effectiveness. Improved hydration (choice C) is important for overall health but does not directly reflect the effectiveness of the cool mist tent. Decreased temperature (choice D) may indicate a reduction in fever but is not specific to the airway condition being treated.