Responses to Inhaled Bronchodilator in Patients with Acute Airflow Obstruction

Abstract

BACKGROUND: Subjective and physiologic responses to inhaled bronchodilator (BD) therapy in patients with obstructive airway disease are variable. Our objectives were (1) to compare changes in breathlessness and lung function based on randomization to either nebulized albuterol or normal saline; (2) to examine the stability of these responses in patients who received albuterol therapy on consecutive days. METHODS: Thirty-nine patients with obstructive airways disease who experienced an acute exacerbation and required hospitalization for therapy were studied before and after inhaled bronchodilator (BD) therapy to evaluate the responses in breathlessness and lung function. On Day 1, outcomes were measured before and after inhaled BD therapy. On Day 2, patients were randomized into a single-blind parallel-design study to receive either inhaled normal saline (placebo) or inhaled albuterol. The same outcomes were measured before and after the two different treatments. Main outcomes were ratings of breathlessness provided by the patient on the 0 to 10 category scale and spirometry-forced vital capacity (FVC) and volume exhaled in the first second of FVC (FEV₁). RESULTS: Two patients were excluded. Mean (SD) age of the 37 patients was 60 ± 18 years. Nineteen patients had chronic obstructive pulmonary disease, 15 had asthma, and 3 had cystic fibrosis. On Day 1, inhaled albuterol caused significant increases in both FVC and FEV1 and a significant reduction in the perception of breathlessness. On Day 2, there were no significant changes in the outcome variables with inhaled normal saline, whereas inhaled albuterol produced bronchodilation and a reduction in the perception of breathlessness. There was no significant correlation (rs = 0.26, p = 0.12) between the changes in FEV1 and the changes in ratings of breathlessness following treatment with inhaled BD. Most patients (62%) hospitalized for an exacerbation of obstructive airway disease reported some relief of breathlessness with inhaled albuterol. CONCLUSIONS: Because no significant relationship between improvement in spirometry and reduction in breathlessness was evident, it may be important to assess the patient's level of breathlessness along with physiologic variables to gain a more comprehensive assessment of the response to inhaled BD therapy.