ASTHMA AND SMALL AIRWAY FUNCTION BY MEASURING FORCED EXPIRATORY FLOW BETWEEN 25% AND 75% OF VITAL CAPACITY

Abstract

Asthma is a chronic inflammation of the airways, characterized by their obstruction. Forced Expiratory Flow between 25% and 75% of vital capacity (FEF 25-75%) measures the speed of exhaled air in the middle expiration and assesses the resistance of the small airways. The study sought to assess the obstruction of the small airways in asthmatics by FEF 25-75% and its relationship with asthma control. This is a cross-sectional and observational study of the cohort "Observational, prospective study to estimate outcomes among patients with asthma in an outpatient clinic of atertiary hospital (OPENASMA)". Data were obtained from the medical records of patients included in the OPENASMA project. The population consists of patients diagnosed with asthma followed at the specific asthma outpatient clinic of HC-UFG/EBSERH, aged over 18 years. The Asthma Control Test (ACT) was greater than or equal to 20 for controlled asthma and less than or equal to 20 for uncontrolled asthma, considering FEF 25-75% less than 60% as reduced. All patients signed an informed consent form. The study sample consisted of 51 participants, mean age 53 years, 11 (21.6%) male and 40 (78.4%) female. Of the total sample, 39 (76.4%) participants had reduced FEF 25-75. Of these, only 10 participants had pre- bronchodilator Forced Vital Capacity (FVC) within normal limits. Regarding asthma control, 25 patients (48%) had uncontrolled asthma. Of the patients who had reduced FEF (25-75), 17 (43.5%) had a good ACT. Of those who had a normal FEF (25-75), 8 (72.72%) also had a good ACT. Therefore, there is a correlation between a reduction in forced expiratory flow between 25% and 75% (FEF 25-75) and inadequate asthma control, as indicated by the Asthma Control Test (ACT).