What is a common sign indicating that an infant may be experiencing increased respiratory distress?

Nasal flaring is a common sign that indicates an infant might be experiencing increased respiratory distress. This occurs as an effort to take in more oxygen when their airway is obstructed or their lungs are not functioning optimally. The nasal passages widen to allow for greater airflow, and this physical response can be a clear indicator of respiratory struggle.

In contrast, a stable heart rate, normal blood pressure, and calm behavior do not signify respiratory distress. A stable heart rate can be observed in various conditions, and normal blood pressure typically suggests that there is no significant cardiovascular compromise. Calm behavior might indicate that the infant is comfortable and is not in distress, contradicting the idea of respiratory issues.