Noninvasive evaluation of contraction and relaxation properties of respiratory muscles in patients after COVID-19 infection
Covid-19, respiratory muscles, relaxation rates, nasal inspiratory pressure, respiratory muscle weakness, nasal inspiratory pressure
Abstract: Lung and airway damage can be caused by COVID-19, therefore, it is important to evaluate the respiratory muscles of subjects infected by the virus. The research aims to non-invasively assess the contraction and relaxation properties of inspiratory muscles, as well as their electrical activity. In this cross-sectional study, carried out at the Onofre Lopes University Hospital (HUOL/EBSERH), the assessment of respiratory muscles regarding their contraction (TC and MRPD) and relaxation (MRR, ½ RT and tau) properties, and electrical activity by surface electromyography (EMGs) of the sternocleidomastoid (SCOM), scalene, parasternal and rectus abdominis muscles was performed non-invasively using the SNIP test in 39 post-COVID-19 subjects (18 women and 21 men) compared to 39 healthy subjects (18 women). and 21 men). Statistical analysis was performed using the GraphPad Prism 8 software, where an alpha (a) of 5% is considered as statistical significance and a power of the test (power) of 80%. Of the relaxation properties obtained from the sniff curve, ½ RT obtained a significant decrease in the COVID-19 group (p<0.05) when compared to healthy individuals. Regarding the contraction properties, there were no significant differences, but a higher value was observed in the CT in the post-COVID-19 subjects. In addition, there was no significant difference between the electromyographic variables, however, there was an increase in electrical activity in the ECOM muscles (139.8 (110 - 167.8 vs 119 (79.2 - 193.6)), scalene (212 .2 (127.8 – 275) vs 135.9 (117.8 – 209)) and parasternal (40 (32.7 – 54.6) vs 29.9 (11.7 – 63)). we concluded that the contraction and relaxation properties of the inspiratory muscles, as well as the electrical activity of these muscles, were not altered after COVID-19. However, further studies need to be carried out.