Alterações de impedância respiratória, complexidade e limitação de fluxo expiratório na exposição ao asbesto

• Autor(a) principal: Peleteiro, Paula Morisco de Sá
• Data de Publicação: 2017
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: Biblioteca Digital de Teses e Dissertações da UERJ
• Texto Completo: http://www.bdtd.uerj.br/handle/1/12690
• topic: Forced oscillations; Asbestosis; Respiratory impedance; Complexity; Limitation of expiratory flow; Oscilações forçadas; Asbestose; Impedância respiratória; Complexidade; Limitação de fluxo expiratório; Asbestose; Aparelho respiratório Doenças; Fluxo expiratório forçado; CNPQ::CIENCIAS DA SAUDE::MEDICINA::CLINICA MEDICA::PNEUMOLOGIA

Occupational and environmental exposure to asbestos fiber is associated with respiratory disease. The need for the development of new, accurate and non-invasive pulmonary function tests are of extreme importance for longitudinal monitoring and represent a simple tool for identifying early changes among exposed populations. Thus, the objective of this study was to evaluate impedance changes, complexity and limitation of expiratory flow in asbestos exposure. A total of 73 subjects were included in the study, being 34 belonging to the control group and 39 with a history of asbestos exposure. Among those exposed, 32 volunteers had radiological findings 0/0 and 7 radiological class 1. 1. The analyzes were performed using the multifrequency forced oscillation (FOT) technique: 1.1. With the classical parameters, 1.2. Compartmental analysis model (RICe), 1.3. Model of fractional order (FrOr); 2. monofrequency FOT at 6Hz: 2.1. Resistance and reactance over the cycle, 2.2. Limitation of expiratory flow (LFE) and 3. FOT monofrequence in 5Hz: 3.1. Impedance over the cycle, 3.2. (RPDE and SampEn) and fluctuations (SD), airflow and impedance parameters. We observed significant resistive changes through the classic FOT parameters: intercept resistance (R0), mean resistance (Rm), resistance at 4 Hz (R4) and slope component in the resistance curve (S) (p <0.001). From the parameters RICe: peripheral resistance (Rp) and total resistance (Rt) (p <0.001). From the parameters FrOr: alpha (α) and beta (β) angles and damping factor (G). Reactive changes were seen for the classical parameters: mean reactance (Xm, p <0.01), resonance frequency (fr, p <0.002) and dynamic compliance (Cdin, p <0.001). For the compliance measured by the RICe model and FrOr model there was also a significant modification (C, p <0.001). Since the modifications from the analysis of the inertance (L), changes were observed in the analysis from the FrOr model.For changes along the respiratory cycle, changes were observed through mean reactance (Xm) and expiratory reactance (Xexp) (p <0.03). The expiratory flow limitation index (iLFE) > 2.8cmH2O/L/s was observed in 3 of the 25 exposed subjects evaluated. The V fluctuations between the inspiratory and expiratory phases of the cycle were higher in the presence of asbestos exposure (p <0.001). As the complexity of the V signal over time decreased with the presence of exposure (p <0.001). The FOT parameters showed a correlation with the standard methods for pulmonary function analysis. Early abnormalities were identified with high diagnostic accuracy (AUC = 0.987) using parameters obtained from the FrOr model. We can conclude, from our findings, that FOT showed to be useful in the identification of resistive and reactive modifications of the respiratory system in subjects exposed to asbestos. The fractional order parameters exceeded the standard and full-order analysis models. Limitation of expiratory flow does not appear to be a common problem in patients exposed to asbestos. The presence of exposure to asbestos introduces a loss of complexity. FOT improved our knowledge of biomechanical abnormalities in asbestos workers and demonstrated a high diagnostic accuracy in the early respiratory changes of these workers. It is possible to infer that this technique represents a useful tool in the early diagnosis and longitudinal follow up of the subjects exposed to asbestos.