Lung Function, Exercise Capacity and Health-Related Quality of Life After Severe COVID-19

Background: Coronavirus disease 2019 (COVID-19) is a respiratory tract infection caused by a newly emergent coronavirus (severe acute respiratory syndrome coronavirus 2; SARS-CoV-2) that was first recognized in Wuhan, China, in December 2019. Currently, this infection reached pandemic levels causing serious diseases in 14% of cases and the potential to progress to acute respiratory distress syndrome (ARDS) with the need for invasive ventilatory support and prolonged hospitalization in intensive care units (ICU). The overall lethality is 2% and the lethality of cases admitted to the ICU varies from 26 to 50%. The medium and long-term impact in survivors of severe COVID-19 on lung function, exercise capacity and health related quality of life (HRQoL) remains to be determined. Aims: To evaluate the early (Visit1: 2-6 months after acute disease) and late (Visit 2: 9-15 months and Visit 3: 18-24 months) effects of severe acute respiratory syndrome on lung function, exercise capacity, respiratory symptoms and HRQoL in patients with confirmed diagnosis of SARS-CoV-2 infection. Material and methods: Prospective cohort of subjects with laboratory confirmed severe COVID-19 (respiratory rate\> 30 breaths/ min; severe respiratory distress; oxyhemoglobin saturation in room air ≤93% or pulmonary involvement\> 50% in chest images). Participants will perform spirometry before and after bronchodilator, lung volumes by body plethysmography, lung diffusion capacity of carbon monoxide, respiratory system resistance by impulse oscillometry and 6-minute walk test (6MWT) after 2-6 months (Visit 1) , 9-15 months (Visit 2), and 18-24 months (Visit 3) of severe COVID-19. When abnormalities in these pulmonary function tests and/or 6MWT were detected, a cardiopulmonary exercise test will be performed. Clinical, laboratory and chest image data during the severe COVID-19 hospitalization will be obtained from medical records. The minimum sample size was estimated as 134 participants to assess at least 5 independent factors to predict lung function, HRQoL and exercise capacity at the early assessment. Notwithstanding, the investigators plan to invite to participate all survivors of severe COVID-19 admitted in hospitals of the state of Rio Grande do Sul (Brazil).