Acurácia das medidas de impedância respiratória para o diagnóstico de asma em crianças

Abstract

Introduction: Detecting airway changes is very important for treatment and diagnosis of asthmatic children. For the efficient and cost-effective adoption of treatment options directed at daily clinical practice, reliable and well-defined biomarkers contribute to the identification of asthma phenotypes and endotypes that are most likely to respond. In this scenario, the forced oscillation technique (FOT) is a promising method in the diagnosis and monitoring of respiratory diseases. Objective: To evidence forced oscillation technique (FOT) parameters that may be used as biomarkers for the diagnosis and monitoring of asthma. Methods: cross-sectional observational study with a quantitative approach. The sample consisted of children and adolescents with asthma and healthy controls, aged 3 to 17 years old, recruited from the São Lucas Hospital of the Pontifical Catholic University of Rio Grande do Sul (PUCRS). The anthropometry, clinical history and respiratory impedance measurements were obtained in all participants. The Research Ethics Committee of the educational institution under opinion No. 3,100,553 approved the project and informed consent was obtained from all participants and their guardians. Results: A total of 101 individuals (61 males) were recruited, 38 with asthma (Asthma group) and 63 healthy controls (Control group). Pre-bronchodilator spectral measurements showed that all variables had significant differences (p <0.001), with higher resistance and lower (negative) reactance in the asthmatic group. In the within-breath analysis, we observed that in the measurements taken before bronchodilator administration, the differences were significant between the two groups, with p≤0.001 in all comparisons except in the difference between mean inspiratory resistance and expiration (dRmean). The accuracy of resistance measures to discriminate asthma was 0.94 for ReE, 0.89 for ReI and 0.76 for ReE-ReI and for reactance was 0.91 for XeE, 0.91 for XeI and 0.79 to XeE-XeI. Correcting estimates of accuracy, sensitivity, specificity, and area under the curve by confounders (stature) on the ROC curve did not change the results. Conclusions: The data obtained suggest that within-breath FOT measurements have excellent discriminatory power for asthma in children and adolescents. Measurement of impedance may aid in the diagnosis of asthma, may also assess the effect of treatment on pulmonary function, and may be used alone or as a complementary method to spirometry. In our sample, the resistance measures had the best discrimination performance.