RT Journal Article SR Electronic T1 Carbon monoxide diffusing capacity (DLCO) in COVID-19 survivors versus idiopathic pulmonary fibrosis (IPF): the pathogenetic features JF European Respiratory Journal JO Eur Respir J FD European Respiratory Society SP PA3900 DO 10.1183/13993003.congress-2021.PA3900 VO 58 IS suppl 65 A1 Shchudro, Olha A1 Bielosludtseva, Ksenia A1 Pertseva, Tetyana A1 Konopkina, Lyudmila A1 Krykhtina, Mariia A1 Konopkina, Lyudmyla YR 2021 UL https://publications.ersnet.org//content/58/suppl_65/PA3900.abstract AB Interstitial: disturbances in COVID-19 pneumonia as like during IPF is already a well-known fact. But no one still compared the DLCO test results between two these diseases.The aim: was to estimate the pathogenic features COVID-19 pneumonia by comparing of their DLCO test with IPF.Materials and methods: Main group was 15 patients (pts) (age – 54,3 (48;65), men – 6 (46,1%)) discharged after severe (10 pts) or critical (5 pts) COVID-19 pneumonia with continuing dyspnea. Сomparison group was 14 pts with confirmed IPF ((age – 65,6 (62;66), men – 7 (50%)). General clinical analysis, resting SpO2 measurement, DLCO.Results: Despite the discharging from the hospital, the DLCO level was lower than norm (80% pred.) in 11 (84,6%). The minimal level of DLCO (47 [40;54] % pred.) was in 5 pts who had critical course of disease and were needed in non-invasive ventilation (NIV) which was similar to IPF (p>0.05). But the main difference between two these diseases was in mechanisms of dysfunction (Table 1). DLCO adj, %pred.Alveolar volume (VA), % pred.The carbon monoxide transfer coefficient (KCO), %predTotal lung capacity (TLC), %predMain group63,6 [54;78]*75,3 [66;94]*82,7 [74;85]75,8 [67;94]*Comparison group43,9 [23;66]53,3 [48;60]83,0 [70;96]55,0 [49;62]Note:*- p<0.05Conclusions: 1) diffusion disturbances in post-COVID-19 pts are well demonstrated during DLCO test, which reach the IPF level after critical COVID-19 pneumonia and NIV; 2) reducing of VA without disturbing KCO after COVID-19 pneumonia plays the main role in pathogenesis of dyspnea, which shows a great role of respiratory gym under the control of dynamic DLCO in pulmonary rehabilitation.FootnotesCite this article as: European Respiratory Journal 2021; 58: Suppl. 65, PA3900.This abstract was presented at the 2021 ERS International Congress, in session “Prediction of exacerbations in patients with COPD”.This is an ERS International Congress abstract. No full-text version is available. Further material to accompany this abstract may be available at www.ers-education.org (ERS member access only).