@article {Lopesrespcare.09193, author = {Agnaldo J Lopes and Thiago T Mafort and Mariana S da Cal and Laura B Monnerat and Patr{\'\i}cia F Litrento and Ingrid Ramos and Raphael F J de Oliveira and Claudia H da Costa and Rog{\'e}rio Rufino}, title = {Impulse Oscillometry Findings and Their Associations With Lung Ultrasound Signs in COVID-19 Survivors}, elocation-id = {respcare.09193}, year = {2021}, doi = {10.4187/respcare.09193}, publisher = {Respiratory Care}, abstract = {BACKGROUND: Because impulse oscillometry (IOS) can detect changes in the small airways and is safer to perform during the COVID-19 pandemic than other pulmonary function tests, it may have value in investigating pulmonary sequelae in COVID-19 survivors. This study evaluated the performance of IOS in detecting lung abnormalities in COVID-19 survivors and investigated the associations of the findings with those of lung ultrasound (LUS) and spirometry.METHODS: In this cross-sectional study, 117 subjects underwent IOS at a frequency range of 4{\textendash}20 Hz 2 months after COVID-19 diagnosis. They also underwent spirometry and LUS, and their aeration scores were calculated.RESULTS: On IOS, the resonance frequency was \> 12 Hz, and the area under the reactance curve was \> 3.60 cm H2O/L/s in 70 (59.8\%) and 55 (47.0\%) subjects, respectively. A heterogeneity of resistance between R4 and R20 (R4-R20) \> 20\% was observed in 60 (51.3\%) participants. Based on their abnormalities in resistive and reactive parameters, 76 (65.0\%) participants had abnormal IOS. Spirometry abnormalities were detected in 40 (34.2\%) cases. LUS was abnormal in 51 (43.6\%) participants, and the median aeration score was 0 (0{\textendash}8) points. Abnormal IOS was associated with abnormal LUS (P \< .001) and abnormal spirometry (P = .002). Abnormal spirometry had a significant but weaker association with abnormal LUS (P = .031). In participants who reported hospitalization, abnormal IOS was associated with both abnormal LUS (P = .001) and abnormal spirometry (P = .006). In participants who did not report hospitalization, abnormal IOS was associated with abnormal LUS (P \< .001) but not abnormal spirometry (P = .063).CONCLUSIONS: In COVID-19 survivors, IOS detected changes even when spirometry is normal. In these individuals, IOS parameters were more strongly associated with abnormalities on LUS than with abnormalities on spirometry.}, issn = {0020-1324}, URL = {https://rc.rcjournal.com/content/early/2021/09/07/respcare.09193}, eprint = {https://rc.rcjournal.com/content/early/2021/09/07/respcare.09193.full.pdf}, journal = {Respiratory Care} }