Avaliação da extensão de comprometimento respiratório analisado em tomografia de tórax em relação à função pulmonar de pacientes acometidos pela covid-19

Abstract

Context: Coronavirus infections present with variable symptoms, from mild colds to severe manifestations such as Severe Acute Respiratory Syndrome (SARS). The lung is recognized as the most affected organ, with descriptions of diffuse destruction of the alveolar epithelium, capillary damage/bleeding, hyaline membrane formation, pulmonary consolidation, and septal fibrous proliferation. In survivors, we can find persistent impairment of lung function and exercise capacity, for months or even years, and residual abnormalities on chest CT scans. Similarly, survivors of pneumonia caused by COVID-19 (Coronavirus Disease 2019) are at high risk of pulmonary, functional, and anatomical complications. However, it is not clear which patients are at greatest risk of developing pulmonary fibrosis and functional loss and who, therefore, should be evaluated sequentially. Knowledge of these sequelae and their risk factors is essential, since the threat of this virus has not yet diminished. Objectives: To analyze pulmonary function tests of patients recovering from COVID-19 and correlate the findings with clinical information and the level of pulmonary impairment seen on chest tomography during the acute phase of the disease. Methods: Retrospective and descriptive study through documentary analysis, carried out in a pulmonology outpatient clinic of a specialized clinic in the city of Manaus/AM from April 2020 to March 2021, where medical records of people with confirmed COVID-19 who had, at the time, chest tomography and pulmonary function tests within sixty days after the end of treatment were evaluated. Previous clinical information was collected (patient's sex, age at the time of the disease, exposure to smoking and previous comorbidities), information about COVID-19 (date of confirmatory examination, severity of the disease and extent of pulmonary impairment on chest tomography performed at the time of the disease) and information about the pulmonary function test performed in the first 60 days after the end of COVID-19 treatment. After that, they were categorized into two groups, according to the classification of severity of the acute disease: non-severe and severe, and statistical analyses were performed. Results: The initial sample collected consisted of 454 medical records, of which 227 were adult men and 227 adult women (mean age 52.2 ± 13.4 years), composed mostly of people between 41 and 65 years old (61.2%), 44.1% presented clinical severity at the time of the disease, the main tomographic findings were in minimal (33.7%) and mild (31.3%) severity, with changes in the pulmonary function test: FVC 83.1% ± 17% and FEV1 85% ± 17.6%. Patients with DM2, BPH, CAD, obesity and kidney transplant recipients showed functional changes in FVC (%) after COVID-19, but only obese patients showed a statistically significant reduction in FVC (%), as well as those with severe disease and patients with chest tomography scans with moderate and severe changes. Regarding the variation in FVC (%) in pulmonary function control exams, only those with a severe tomographic pattern at the time of the disease showed a statistically significant improvement in FVC of 13.9%, when compared to the previous exam. Patients with pulmonary emphysema showed a statistically significant reduction in FEV1 (%), as well as those with chest tomography scans with moderate and severe changes. Regarding the variation in FEV1 (%) in pulmonary function control exams, only patients with pulmonary emphysema and SLE presented a significant variation, but without statistical significance, as well as the tomographic pattern, severity of the disease and history of smoking. Conclusion: This study demonstrated that functional changes in respiratory capacity after COVID-19 were directly related to the severity of the disease presentation, the degree of tomographic impairment at the time of the disease and associated comorbidities, thus generating an impact on the loss of lung function.