Estudo piloto dos efeitos imediatos da Pressão Positiva Continua Nas Vias Aéreas (CPAP) em asmáticos avaliados por técnica de oscilações forçadas

Abstract

Introduction: Asthma is a very frequent disease and in Brazil, its average prevalence is 4.5%, ranging from 2.6% to 9.7%. Researchers have suggested exploring the mechanisms of inflammatory behavior of the smooth muscle of the airways in asthmatic patients, reflecting a characteristic variability of their heterogeneous nature. The modified forced-oscillation technique (FOT-ST) is a new method that has the potential to detect early changes in the respiratory system in this population. Objective: To assess the immediate effects of airway CPAP on asthmatic patients and healthy subjects, as well as evaluate the discriminatory power of airway resistance measurement before and after the use of CPAP for the diagnosis of asthma. Materials and methods: The sample was selected for convenience, being composed of asthmatic and healthy young adults, aged > 18 years. Anthropometry, clinical history, and measures of spectral and temporal impedance were obtained in all participants. An intervention protocol with CPAP was performed. Results: We included 07 young adults with asthma and 06 healthy subjects from the analysis of the respiratory symptoms questionnaire. The mean age was around 24.1 ± 3.3 and 25.8 ± 9.2 years, respectively. The female sex predominated. The mean BMI (kg / m2) was 24.3 ± 2.4 (asthmatics) and 22.7 ± 3.0 (healthy). Most of the sample was composed of Caucasian subjects. The effect of CPAP on respiratory impedance (6-32 Hz) increased resistance and decreased complacency in asthmatics, reduced resistance and increased compliance in healthy controls. There are no significant differences between the two groups for baseline impedance measurements or after CPAP. Conclusions: The findings of the present study demonstrated that asthmatic subjects seem to have a different response in their respiratory impedance when compared to healthy subjects. These differences may be relatively accentuated with increased asthma severity and have potential use as biomarkers for diagnosis or monitoring of their clinical course.