Análise da Limitação de Fluxo Expiratório por Meio da Avaliação do Padrão de fluxo Fluxo Epiratório eEpontâneo: Instrumentação e Testes em Normais e Pacientes

摘要

In order to simplify the evaluation of expiratory flow limitation (EFL) in patients with respiratory disorders, wc designed a new system in which EFL was detected by using a nasal cannula during spontaneous ventilation. The processing, presentation and data storage functions are conducted by a portable virtual instrument. The system displays the mean derivative of the expiratory airflow signal (α_m). After the design details are described, the methodology was evaluated in 15 normal volunteers and 15 patients. This analysis revealed a linear correlation between α_m and the EFL (R=-0,74; p＜0,0001). The evaluation of the clinicai usefulness showed that α_m is sufficiently accurate for clinicai use. We concluded that the developed system could be a useful tool for the evaluation of EFL.