Mechanism(s) of Airflow Limitation During Exacerbation of Asthma

Conditions studied

Asthma

About this study

The purpose of this study is to evaluate the site and mechanisms responsible for expiratory airflow limitation in chronic, treated, non-smoking, stable asthmatics with moderate to severe persistent expiratory airflow obstruction. Treatment will include inhaled corticosteroids and long acting beta2agonists. The investigators are interested in determining whether the large and/or small airways are the predominant site of airflow limitation. The investigators are also interested in determining whether intrinsic small airways obstruction and/or loss of lung elastic recoil is responsible for expiratory airflow limitation. The investigators are also interested to evaluate the role of varying doses of inhaled corticosteroids to suppress large and small airway inflammation using exhaled nitric oxide as surrogate markers of inflammation. For comparison purposes, spirometry and measurements of exhaled nitric oxide will also be obtained if possible during a naturally occurring exacerbation of asthma.

Interventions

• Drug: fluticasone/salmeterol in all asthmatics — budesonide 80ug/formoterol 4.5ug, 2 inhalations bid X 20-60 days or fluticasone 100ug/salmeterol 50ug, 1 inhalation bid X 20-60 days
• Drug: budesonide/formoterol or fluticasone/salmeterol in all asthmatics — budesonide 160ug/formoterol 4.5ug, 2 inhalations bid or fluticasone 250ug/salmeterol 50ug, 1 inhalations bid

Primary outcomes

• Exhaled nitric oxide (20-60 days)

Eligibility information

Study locations

• Arthur F Gelb Medical Corporation, Lakewood, California 90712 United States