What is the most appropriate nursing action to evaluate the effectiveness of a bronchodilator in a patient with asthma?

Asthma is a chronic inflammatory airway disorder involving bronchoconstriction, airway hyperresponsiveness, reversible airflow limitation, and mucus hypersecretion. Acute exacerbations reduce expiratory flow rates, causing wheezing, dyspnea, decreased oxygenation, and impaired ventilation measurable through objective pulmonary function testing. Rationale: A. Assessing skin turgor evaluates hydration status and is unrelated to bronchodilator effectiveness. Asthma management focuses on airway patency and ventilation. This intervention does not provide information about airflow improvement or bronchial smooth muscle relaxation. B. Monitoring blood pressure and heart rate detects systemic side effects such as tachycardia from beta-agonists. However, it does not directly measure respiratory improvement. Cardiovascular changes do not indicate the degree of bronchodilation or airway responsiveness. C. Measuring peak expiratory flow rate before and after bronchodilator administration provides objective evidence of airway improvement. Increased values reflect reduced airway obstruction and effective bronchodilation. This is the most reliable method to assess treatment response in asthma management. D. Capillary refill time assesses peripheral perfusion and circulatory status. It is not related to pulmonary function or airway patency. This measure does not reflect changes in respiratory status or effectiveness of bronchodilator therapy.