RESUMEN
INTRODUCTION: Asthma, a chronic lung disease, is a major health challenge worldwide with increased addressability to health services. There are different asthma phenotypes, which have different evolution and can be specifically tracked. The measurement of fractional expired nitric oxide (FeNo) with different devices reflects the eosinophilic inflammation of the airways, and can be used to evaluate the allergic phenotype and predict the treatment responses. The new GINA (Global Initiative for Asthma) guideline recommends FeNO monitoring to assess adherence to cortisone treatment in high doses before prescribing biological treatment, and as a means of monitoring the decrease in oral corticosteroid treatment. OBJECTIVE: The aim of the study is to analyze the applicability of FeNO in monitoring response to therapy. MATERIAL AND METHODS: An observational study was carried out on 129 subjects with a previously established diagnosis of asthma. The research was based on the determination of FeNO with NObreath. Those with intermediate FeNO received a low dose of inhaled corticosteroids in mono/dual therapy, those with increased FeNO received medium ICS mono/dual therapy. FeNO testing, its values and doses of ICS were below the the ATS / ERS guidelines. RESULTS: FeNO reduction is strictly dependent on the cortisone dose. Applying the dual therapy from the beginning does not bring additional benefits in comparison with cortisone in monotherapy, in terms of FeNO value. CONCLUSIONS: Recommendations that include FeNO testing can help monitor response to treatment.