Análise de geradores de pressão a alto-falantes utilizados na técnica de oscilações forçadas.

Abstract

One of the ways to the evaluation of the Pulmonary Function is the use of the Forced Oscillation Technique (FOT). Pressure Generators, which can be based on loudspeakers, are needed in its establishment. The analysis of these generators is important to the determination of the mechanic impedance of the Respiratory System (Zrs). In the beginning, aiming the study about the Transference Function of the pressure generators, the influence of the impedance in the FOT system had to be verified. Based on that, the main objective of this Thesis work became to be the determination of the influence of these impedances which are going to be analysed in three different structures implemented in the System. These impedances are the consequence of tubes put between the system and the atmosphere. In this way, experiments were made using tubes of different diameters to each length of 80 and 160cm. These tubes have the purpose to allow the renewal air inhaled in the System when positioned close to the charge or to the patient, and allow the loudspeaker's cone a better movement when positioned at the frontal part of the pressure generator. In this way, the measures of the levels of pressures in the system were taken: close to the generator and close to the charge, having objective to monitorate the levels of pressures that are generated, at the moment of the Forced Oscillations, making possible the implementation of systems that allow a spontaneous breath and without damages to the patient. The whole process has been accomplished using different pressure generators. Through the results was possible to conclude that there is influence of the length, diameter, and position of the tubes in the determination of the Mechanic Respiratory Impedance. It has also been defined a better structure, able to represent with quality the mechanical impedance of the system, allowing a better analysis and diagnosis about the Pulmonary Function.