Analysis of Respiratory System Functional Parameters at Different Time Points after COVID-19

The objective: to define the type and evaluate the severity of respiratory functional disorders after COVID-19. \Subjects and Methods. A retrospective observational study was conducted. The following parameters were analyzed: demographic data, data from chest computed tomography during the acute period of the disease (CTmax), parameters of pulmonary function tests (PFT) – spirometry, body plethysmography and diffusion test. Those data were collected in 341 patients, 262 (76.8%) of them were men (median age – 48 (41.5–57) years, median durtaion of Period A (onset of COVID-19 before PFT) made 53 (28.5–111) days). Depending on duration of Period A, patients were divided into three groups: Group 1 – up to 90 days (n=221), Group 2 – 90-180 days (n=80), and Group 3 – more than 180 days (n=40). In patients of Groups 1, 2 and 3, in 68.3%, 47.5% and 32,5% of cases, respectively, disorders of diffusing lung capacity were recorded, which were associated to a greater extent with CTmax, and to a lesser extent with duration of Period A. The restrictive type of ventilation disorders was observed in 33.5% and 11% of cases in Groups 1 and 2, no restriction was detected in Group 3, airway obstruction was detected in 8%, 5%, 7.5% of cases in Groups 1, 2 and 3 respectively.Conclusion. Disorder of diffusing lung capacity was the most common functional disorder of the respiratory system after COVID-19, and therefore it is advisable to include a diffusion test along with spirometry to the examination plan of such patients.