Carbon monoxide diffusing capacity (DLCO) in COVID-19 survivors versus idiopathic pulmonary fibrosis (IPF): the pathogenetic features

Abstract

<b>Interstitial:</b> 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. <b>The aim:</b> was to estimate the pathogenic features COVID-19 pneumonia by comparing of their DLCO test with IPF. <b>Materials and methods:</b> 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. <b>Results:</b> 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&gt;0.05). But the main difference between two these diseases was in mechanisms of dysfunction (Table 1). <b>Conclusions:</b> 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&nbsp;V_A without disturbing KCO after COVID-19 pneumonia plays the main role&nbsp;in pathogenesis of dyspnea, which shows a great role of respiratory gym under the control of&nbsp;dynamic DLCO in pulmonary&nbsp;rehabilitation.