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
Pulmonary and airway damage can be caused by COVID-19, so since the World Health Organization declared the disease a pandemic in March 2020, the need to identify these manifestations and their losses after the virus infection. Thus, in this case-control study, the assessment of respiratory muscles, in terms of contraction and relaxation properties, was performed non-invasively in 34 individuals who were affected by COVID-19. These patients were divided into three subgroups according to hospitalization, in the ICU, infirmary or not, and were submitted to the maximal inspiratory and expiratory pressure test (MIP and MEP), nasal inspiratory pressure test (SNIP) and the reverse sniff. or nasal expiratory pressure (RSNEP). The statistical analysis was performed using the GraphPad Prism 6 software, where an alpha (a) of 5% is considered as statistical significance and a test power (power) of 80%. When intergroup comparison was performed, the maximum relaxation rate (MRR) showed a significant decrease (P <0.0001), whereas the maximum pressure development rate (MRPD) (p = 0.927), Time of contraction (TC) (p = 0.115) and Tau (p = 0.131). Slow vital capacity (FVC) and Medium forced expiratory flow (FEF25-75%) were parameters that obtained a large difference between groups (P <0.0001). The contractile properties and relaxation rates of the respiratory muscles are discriminatory parameters between the groups, especially those who were admitted to the ICU, with changes in the respiratory dynamics caused by the virus.