Instrumentation for respiratory flow estimation using tracheal sounds analysis: Design and evaluation in measurements of respiratory cycle periods and airflow amplitude

The increase in the incidence of respiratory diseases resulted in an increased interest in the improvement of the instruments used in research and diagnosis of respiratory dysfunction. We developed a non-invasive instrument able to estimate ventilation parameters by means of tracheal sounds analysis (TSA). The development of the hardware and software used in the instrument is described, as well as initial in vivo results obtained in a normal subjects. These tests showed that the TSA was able to provide adequate airflow estimative. Moreover, it was found that accurate respiratory periods can be obtained from tracheal sounds These results were in close agreement with the physiology, confirming the high scientific and clinical potential of this system.