The end of the acute period of COVID-19 does not mean complete recovery. Observation of patients in the post-COVID-19 period showed that a significant number of people experience shortness of breath, fatigue, muscle weakness, sleep disorders, cough, palpitations, so the term post-COVID-19 syndrome was coined. The examination to identify the causes of complaints of COVID-19 convalescents should include lung function assessment.The aim of the study was to assess the dynamics of lung function 4 months after hospitalization for COVID-19.Methods. 31 patients (26 males, the median age was 49 years) underwent traditional pulmonary function tests (PFTs) (spirometry, body plethysmography, test of diffusing lung capacity) and impulse oscillometry (IOS). Results. During the 1^st visit, the average PFTs and IOS parameters were within the normal range in the whole group, apart from the diffusing lung capacity (DL_CO), which was reduced mildly (on the border with moderate) in 77% of patients. During the 2^nd visit, which was conducted on average 102 days after the 1^st one, 58% of patients demonstrated abnormal lung diffusion capacity. The second assessment revealed a statistically significant increase in the slow and forced vital capacity (VC and FVC), the forced exhalation volume in 1 second (FEV₁), total lung capacity (TLC), DL_CO, and a decrease in the ratio of FEV₁/FVC and the residual lung volume to TLC ratio.Conclusion. Post-COVID-19 patients show a statistically significant improvement of their lung function 4 months after hospital discharge. A systematic follow-up is essential for such patients to detect lung function abnormalities and correct them.

Background. Lung function tests should be performed to patients with penetrating wounds of the lungs to identify lung function disorders, and the data obtained should be taken into account when correcting medical treatment and prescribing individual medical rehabilitation programs. The aim was to study the impact of penetrating lung wounds on the lung function in the early recovery period. Materials and methods. 13 patients were enrolled in the study, 100% male, median age 26 [21; 31] years. Spirometry, body plethysmography, and a diffusion test were performed on an average of 14 days from the injury. Results. A prospective cross-sectional study was performed. A moderate decrease in the vital capacity (VC), the forced vital capacity (FVC), the volume of forced exhalation in the first second (FEV1) was revealed while the total lung capacity (TLCpl) and the FEV1/FVC ratio were within normal values. However, in 2 (15.4%) and 3 (23%) patients, a restrictive ventilation disorders (TLC lower limit of normal) was detected when using Global Lung Function Initiative (GLI) and European Community for Steel and Coal (ECSC) 1993 predicted value system, respectively. The residual lung (RV) and RV/TLCpl were increased. Functional residual capacity (FRC), FRCpl/TLCpl, airway resistance remained within normal values. The diffusion lung capacity impairment was detected in 92.3% and 61.5% cases according to the ECSC 1993 and the GLI system, respectively. Conclusion. In the early period of recovery after penetrating lung wounds, a nonspecific pattern of ventilation disorders was the most often abnormality namely a decrease in VC while TLC and FEV1/FVC were within normal values. Less frequently, the classic restrictive pattern of ventilation disorders was diagnosed. Besides, the diffusion lung capacity impairment was detected. The system of predicted values has a significant impact on the frequency of detection of the lung function disorders. The revealed functional disorders should be taken into account for adjusting medical and rehabilitation interventions.

The respiratory pump that provides pulmonary ventilation includes the respiratory center, peripheral nervous system, chest and respiratory muscles.The aim of this study was to evaluate the activity of the respiratory center and the respiratory muscles strength after COVID-19 (COronaVIrus Disease 2019).Methods. The observational retrospective cross-sectional study included 74 post-COVID-19 patients (56 (76%) men, median age – 48 years). Spirometry, body plethysmography, measurement of lung diffusing capacity (DLCO), maximal inspiratory and expiratory pressures (MIP and MEP), and airway occlusion pressure after 0.1 sec (P0.1) were performed. In addition, dyspnea was assessed in 31 patients using the mMRC scale and muscle strength was assessed in 27 of those patients using MRC Weakness scale.Results. The median time from the COVID-19 onset to pulmonary function tests (PFTs) was 120 days. The total sample was divided into 2 subgroups: 1 – P0.1 ≤ 0.15 kPa (norm), 2 – > 0.15 kPa. The lung volumes, airway resistance, MIP, and MEP were within normal values in most patients, whereas DLCO was reduced in 59% of cases in both the total sample and the subgroups. Mild dyspnea and a slight decrease in muscle strength were also detected. Statistically significant differences between the subgroups were found in the lung volumes (lower) and airway resistance (higher) in subgroup 2. Correlation analysis revealed moderate negative correlations between P0.1 and ventilation parameters.Conclusion. Measurement of P0.1 is a simple and non-invasive method for assessing pulmonary function. In our study, an increase in P0.1 was detected in 45% of post-COVID-19 cases, possibly due to impaired pulmonary mechanics despite the preserved pulmonary ventilation as well as normal MIP and MEP values.

COVID-19 (Coronavirus disease 2019) is an infectious disease caused by the coronavirus SARS-CoV-2, characterized by a high level of morbidity and mortality. A new coronavirus infection affects all organs and systems and often occurs with lung damage and respiratory failure. In a significant part of patients after the acute period of COVID-19, the symptoms of the disease persist, but the most problematic symptoms are the ones regarding lung damage that persists for a long amount of time. This review summarizes the results of our research in 20202021. The purpose of the conducted studies was to estimate the functional parameters of the respiratory system in patients that have been infected by COVID-19. Along with conventional pulmonary function tests (spirometry, body plethysmography and diffusion test), impulse oscillometry, the multiple-breath nitrogen washout test, determination of the maximum inspiratory and expiratory pressures were performed in all patients. Thus, we evaluated the ventilation and gas exchange function of the bronchopulmonary system, the functional state of the peripheral parts of the lungs, including the small airways, the uniformity of pulmonary ventilation and the strength of the respiratory muscles in different periods of recovery after COVID-19, including the follow-up after medical rehabilitation. To sum up, comprehensive functional assessment of the respiratory system is an important clinical tool that allows the planning of pharmacotherapy and to create individual programs of medical rehabilitation of patients who had COVID-19.