Original Article

Does Mild Coronavirus Disease 2019 Pneumonia in Healthy Adults Cause Permanent Small Airway Injury?

Authors: Buket Caliskaner Ozturk, MD, Enes Furkan Aykac, MD, Ilgim Vardaloglu, MD, Nihal Enşen, PhD, Gunay Can, MD, Sermin Borekci, MD, Bilun Gemicioglu, MD, PhD


Objectives: Impulse oscillometry (IOS) is a type of oscillation technique that measures the input impedance (Z) of the respiratory system and can be used to detect pathological changes in the small airways at an early stage. Although coronavirus disease 2019 (COVID-19) affects the vascular and parenchymal structures in the lung, chronic postinfection coughs also may be attributed to small airway pathologies. Our research aimed to use IOS for the assessment of the presence of small airway resistance (R) in patients who have had COVID-19.

Methods: Thirty-eight patients with past COVID-19 infections and without any presence or medical treatment of an airway disease who presented to the post-COVID outpatient clinic with coughing symptoms were included in the study. The control group consisted of 17 patients with no past COVID-19 infection and without an airway disease. IOS and spirometry were performed twice in the case group, at 3 and 6 months after COVID-19.

Results: The mean age of the case group was 44.7 ± 12.3 years, whereas the mean age of the control group was 49.4 ± 11.8 years. The case group consisted of 38 patients, whereas 17 patients constituted the control group. No statistically significant difference was found between the two groups in the first and second test measurements, performed 3 months apart (P > 0.05).

Conclusions: The fact that there was no difference between respiratory system impedance, airway resistance, and spirometry values between groups with and without past COVID-19 infections supported the hypothesis that small airways were not affected 3 months after COVID-19.
Posted in: Infectious Disease133

This content is limited to qualifying members.

Existing members, please login first

If you have an existing account please login now to access this article or view purchase options.

Purchase only this article ($25)

Create a free account, then purchase this article to download or access it online for 24 hours.

Purchase an SMJ online subscription ($75)

Create a free account, then purchase a subscription to get complete access to all articles for a full year.

Purchase a membership plan (fees vary)

Premium members can access all articles plus recieve many more benefits. View all membership plans and benefit packages.


1. Shah AS, Wong AW, Hague CJ, et al. A prospective study of 12-week respiratory outcomes in COVID-19-related hospitalisations. Thorax 2020;76:402–404.
2. Daher A, Balfanz P, Cornelissen C, et al. Follow up of patients with severe coronavirus disease 2019 (COVID-19): pulmonary and extrapulmonary disease sequelae. Respir Med 2020;174:106197.
3. Zhao YM, Shang YM, Song WB, et al. Follow-up study of the pulmonary function and related physiological characteristics of COVID-19 survivors three months after recovery. EClinicalMedicine 2020;25:100463.
4. Núñez-Fernández M, Ramos-Hernández C, García-Río F, et al. Alterations in respiratory function test three months after hospitalisation for COVID-19 pneumonia: value of determining nitric oxide diffusion. J Clin Med 2021; 10:2119.
5. Fumagalli A, Misuraca C, Bianchi A, et al. Long-term changes in pulmonary function among patients surviving to COVID-19 pneumonia. Infection 2022; 50:1019–1022.
6. Lopes AJ, Litrento PF, Provenzano BC, et al. Small airway dysfunction on impulse oscillometry and pathological signs on lung ultrasound are frequent in post-COVID-19 patients with persistent respiratory symptoms. PLoS One 2021;16:e0260679.
7. Lopes AJ, Mafort TT, da Cal MS, et al. Impulse oscillometry findings and their associations with lung ultrasound signs in COVID-19 survivors. Respir Care 2021;66:1691–1698.
8. King GG, Bates J, Berger KI, et al. Technical standards for respiratory oscillometry. Eur Respir J 2020;55:1900753.
9. Oostveen E, MacLeod D, Lorino H, et al. The forced oscillation technique in clinical practice: methodology, recommendations and future developments. Eur Respir J 2003;22:1026–1041.
10. Graham BL, Steenbruggen I, Miller MR, et al. Standardization of spirometry 2019 update. An official American Thoracic Society and European Respiratory Society technical statement. Am J Respir Crit Care Med 2019;200:e70–e88.
11. Orzes N, Pini L, Levi G, et al. A prospective evaluation of lung function at three and six months in patients with previous SARS-COV-2 pneumonia. Respir Med 2021;186:106541.
12. Huang Y, Tan C, Wu J, et al. Impact of coronavirus disease 2019 on pulmonary function in early convalescence phase. Respir Res 2020;21:163.
13. Cassar MP, Tunnicliffe EM, Petousi N, et al. Symptom persistence despite improvement in cardiopulmonary health—insights from longitudinal CMR, CPET and lung function testing post-COVID-19. EClinicalMedicine 2021; 41:101159.
14. Niyatiwatchanchai N, Deesomchok A, Chaiwong W, et al. Comparative study of early impacts of post-COVID-19 pneumonia on clinical manifestations, pulmonary function, and chest radiographs. Medicina (Kaunas) 2022; 58:216.