Exhaled Carbon Monoxide in Asthmatic Adults with Bronchial Reactivity: A Prospective Study

Abstract

Hypothesis. We hypothesized that eCO may permit non-invasive assessment of disease activity in adults with asthma and bronchial reactivity. Methods. A total of 209 participants 18 to 65 years of age with a diagnosis of asthma and bronchial reactivity provided data for analysis. The association between eCO and bronchial reactivity, forced expiratory volume in one second (FEV₁), forced vital capacity (FVC), peak expiratory flow rate measurements (PEFR), asthma symptoms score, and bronchodilator use cross-sectionally and within-subject change in eCO were analyzed in relation to change in these variables over 6 weeks. Results. There was no difference in eCO in those who were taking inhaled corticosteroids and those who were not (p = 0.33). There was also no cross-sectional or within-in subject association between eCO and bronchial reactivity, FEV₁, FVC, PEFR, symptoms score, or bronchodilator use. Conclusions. In a population of adults with bronchial reactivity, eCO has no or very limited potential as a biomarker of asthma activity.

Keywords:

• carbon monoxide
• asthma
• bronchial reactivity
• lung function
• prospective study