Avaliação do Modo Respiratório por meio da Termografia

Abstract

Topic: Use of the infrared thermography technique to assess breathing modes. Objective: To develop a method to analyze breathing modes using infrared thermography. Methods: This is an exploratory observational cross-sectional study, conducted with a convenience sample and approved by the Research Ethics Committee of the Federal University of Minas Gerais (UFMG) under evaluation report CAAE 4.532.837. The participants included Speech-Language Hearing Sciences students and professors. Two pieces of research were carried out to construct the dissertation volume: a pilot study with four volunteer women, totaling 38 thermograms, to establish the methodology (pilot study) and research with 20 participants and a total of 240 thermograms (main study). The first stage of data collection (pilot study) was conducted at the Thermometry Laboratory of the School of Engineering at UFMG (LabTerm), whereas the second stage was conducted at the Functional Health Observatory in Speech-Language-Hearing Sciences of the School of Medicine at UFMG. The selection criteria were as follows: subjects 18 years or older, without physical, neurological, and/or cognitive changes that might prevent or hinder their collaboration during the examination. The exclusion criteria were as follows: subjects using bandages on the skin and/or other factors that might compromise its exposure to a balanced temperature environment; who had done physical exercises, been submitted to acupuncture, massage, or electrical stimulation, attended saunas, or been prolonged exposure to the sun for up to 24 hours before measurements are taken were; who used bronchodilators and vasoactive drugs; who had a fever, allergic rhinitis, influenza symptoms and/or a cold on the day of the tests; bearded men; women on their fertile or menstrual days. The thermal cameras used were the FLIR SC660 (in the first phase of the study) and FLIR A315 (in the second phase). All trials complied with the recommendations of the American Academy of Thermology and the Brazilian Thermology Society. The resulting thermograms were incorporated into the FLIR Tools software and had their regions of interest (ROI) - noise and mouth - analyzed, in the pilot study, using three selection forms: ellipse, rectangle, and line. Also, the minimum, mean, and maximum temperatures of these regions were obtained. As for the second study, only the ellipse was used because its results had been satisfactory in the pilot study, adapting better to the anatomy of regions of interest. For the second article, a larger sample was assessed (20 participants) and the normalized nondimensional temperature was calculated. The temperatures were also collected by two raters and replicated by one of them to assess the inter- and intrarater agreement. Results: In the pilot study, there was greater variability in the measures obtained with line selection, revealing it to be a limited measure. There were no differences between the rectangle and ellipse measures; however, the ellipse proved to be better employed in temperature collection because it fits better to the anatomical characteristics, more adequately contouring the mouth and noise. The results of the comparison between the nose and mouth temperatures when inhaling and exhaling showed a statistically relevant difference in the mostly measures taken, except for the mean inhale temperatures using the rectangle and ellipse. The mouth temperature was always higher than the nose temperature. The comparison of the temperature values between nasal and mouth/oronasal breathing revealed that the mean mouth temperature measures using the rectangle and ellipse selection when inhaling differentiated the breathing mode, both when inhaling and exhaling. As for the second study, there were statistically significant differences in the comparison between the mouth temperatures in nasal and mouth/oronasal breathing. The exhale temperatures were higher than the inhale ones in mouth/oronasal breathing (through the nose and the mouth) and nasal breathing (only through the nose). Statistically relevant results for the mouth were observed in the analysis of temperature difference (ΔT) between exhaling and inhaling, indicating once again that the mouth may be used as ROI in the comparison of breathing modes. Conclusion: Thermography proved to be potential technique to analyze and assess breathing modes. The results obtained in both studies were important. Hence, an assessment protocol can be developed.