Diagnosing ventilation inhomogeneity after COVID-19 by multiple-breath nitrogen washout test

The aim was to evaluate the ventilation inhomogeneity (VIH) by multiple-breath nitrogen washout test (MBNW) after COVID-19 and identify relationship of lung clearance index (LCI) with other functional parameters respiratory system. Methods. cross-sectional study included 35 patients (97% men); median age 44 years. Spirometry, body plethysmography, diffusing capacity for carbon monoxide (DL co ), MBNW test, impulse oscillometry were performed. Dyspnea evaluated mMRC scale. performed using Easy-one Pro, MBW Module (ndd Medizintechnik AG, Switzerland). Results . divided into 2 groups. Group 1 21 (60%) who not diagnosed VIH. 14 (40%) testing period 72 (47 - 109) days from onset COVID-19. maximum volume damage determined high-resolution computed tomography (CT max ) 50% in acute disease 12% during study. medians all analyzed remained normal cohort as well groups 2, except resonance frequency (f res group 2. Statistically significant differences found between absolute dependence resistance (R5 R20), reactance area (A X f Significant also pathological changes vital capacity, forced expiratory first second (FEV R20). abnormalities more common A correlation shown LCI ratio residual total AX, fres, relative resistance, CTmax, FEV1 trasfer-factor ). Conclusion Seventy-two CoVID-19, detected 40% patients, decreased DL 23%, airway obstruction 11.4%, restrictive ventilatory defect 8.6%. Correlations , spirometry parameters, oscillometry, CT