A nurse is caring for a toddler who is experiencing an acute asthma attack. Which of the following findings indicates improvement?

The correct answer is D: Decreased stridor. Stridor is a high-pitched, noisy breathing sound that indicates upper airway obstruction, commonly seen in asthma attacks. A decrease in stridor suggests improved airway patency and ventilation, indicating that the toddler's condition is improving. Improved hydration (A) is important but doesn't directly indicate respiratory improvement. A barking cough (B) is typically associated with croup, not asthma. Decreased temperature (C) may indicate resolution of a fever but doesn't specifically reflect respiratory status.