Airflow limitation in brazilian caucasians: FEV1 /FEV6 vs. FEV1 /FVC

• Autor(a) principal: Soares, André Luis Pinto
• Data de Publicação: 2008
• Outros Autores: Rodrigues, Sílvia Carla Sousa, Pereira, Carlos Alberto de Castro
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Institucional da UFRN
• Texto Completo: https://repositorio.ufrn.br/handle/123456789/52476
• topic: forced expiratory volume; vital capacity; airway obstruction; spirometry; respiratory function tests.; volume expiratório forçado; capacidade vital; testes de função pulmonar; obstrução das vias respiratórias; espirometria

Objective: To evaluate the use of the forced expiratory volume in one second/forced expiratory volume in six seconds (FEV1 /FEV6 ) ratio as an alternative to the FEV1 /forced vital capacity (FVC) ratio in the detection of mild airway obstruction. Methods: Reference equations for the Brazilian population in 2006 were used in order to determine the lower limits of normality for the FEV1 /FEV6 and FEV1 /FVC ratios. The spirometry findings of 155 patients from 20 to 84 years of age were analyzed. All of the patients presented the following: a < 15% difference between predicted and observed FEV1 /FVC ratio; an FEV1 ≥ 60% of predicted; and an exhalation time of at least 6 s. The Brazilian Thoracic Society criteria for acceptability and reproducibility in spirometry were met. Results: Mean values (± SD) for FEV1 /FEV6 and FEV1 /FVC were 73 ± 4% and 75 ± 3%, respectively. Using the FEV1 /FVC ratio, we identified airflow obstruction in 61 patients, compared with only 46 patients when we used the FEV1 /FEV6 ratio, showing a sensitivity of 75% (p < 0.001). Conclusions: The FEV1 /FEV6 ratio has poor sensitivity and should not be used to replace the FEV1 /FVC ratio in the diagnosis of mild airway obstruction.