Evaluation of the chronic effects of COVID-19 infection on the respiratory system by pulmonary ultrasound and pulmonary function tests

Objective: The aim of this study is to evaluate whether there are chronic effects in the pulmonary system and systemic level in individuals in the post COVID-19 period in order to elucidate the involvement of inflammation after recovery. In addition, a perspective on the utility of pulmonary function testing and pulmonary ultrasound in the evaluation of chronic effects and patient follow-up will is aimed to be provided. By measuring the protein levels of inflammatory markers along with the data abovementioned, a foresight regarding the long-term effects of the previous infection at both functional and immunological levels will be obtained, allowing us to evaluate the post-COVID-19 period from different angles. Materials and Methods: Volunteers who recovered from COVID-19 infection at least 3 months or more were included in the study, while healthy volunteers who did not have the infection were enrolled as the control group. Two groups were compared by evaluating chest x-ray scores (CXR), lung ultrasound scores (LUSS), pulmonary function tests and inflammatory cytokine levels (TNF-α, IL-1, IL-6, IL-17A). Results: There was no significant difference in the evaluation of lung ultrasonography and chest radiography in subjects with COVID-19 infection compared to subjects without COVID-19 infection. In subjects with COVID-19 infection, TLC was significantly lower in the female patient group compared to subjects without COVID-19 infection. IL-6 and IL-17A levels were significantly higher in subjects with COVID-19 infection compared to subjects without COVID-19 infection. Conclusion: There were no significant differences in lung ultrasonography and chest radiography evaluation in subjects with COVID-19 infection compared to subjects without COVID-19 infection, but there were significant differences in pulmonary function test and inflammatory cytokine levels. The results of the study suggest that even aymptomatic COVID-19 infection may lead to long-term changes in lung parenchyma and lead to systemic inflammation, but further studies are needed to support this hypothesis due to the lack of similar studies.