Which of the following would indicate the effectiveness of a bronchodilator?

A. Retractions on assessment: Retractions suggest increased respiratory effort and are a sign of respiratory distress. Their presence indicates that the airway is still obstructed or the patient is struggling to breathe, suggesting the bronchodilator has not been effective. B. Chest tightness: Chest tightness is a subjective symptom often associated with bronchospasm or airway constriction. If it persists after bronchodilator use, it signals continued respiratory compromise and inadequate relief from the medication. C. Use of accessory muscles: Use of accessory muscles indicates labored breathing and ongoing difficulty with ventilation. Effective bronchodilation should reduce the work of breathing and minimize reliance on these muscles. D. SpO₂ increased from 87% to 94%: An increase in oxygen saturation indicates improved gas exchange and oxygenation, reflecting that the bronchodilator has successfully opened the airways. This is a measurable and objective sign of medication effectiveness.