Detection of Small Airway Dysfunction in Asymptomatic Smokers with Preserved Spirometry: The Value of the Impulse Oscillometry System

• Main Authors: Pisi R, Aiello M, Frizzelli A, Calzetta L, Marchi L, Bertorelli G, Pisi G, Chetta A
• Format: Article
• Language: English
• Published: Dove Medical Press 2021-09-01
• Series: International Journal of COPD
• Subjects: small airway dysfunction; impulse oscillometry system; spirometry; smokers; copd
• Online Access: https://www.dovepress.com/detection-of-small-airway-dysfunction-in-asymptomatic-smokers-with-pre-peer-reviewed-fulltext-article-COPD

Roberta Pisi,1 Marina Aiello,1 Annalisa Frizzelli,1 Luigino Calzetta,1 Laura Marchi,1 Giuseppina Bertorelli,1 Giovanna Pisi,2 Alfredo Chetta1 1Department of Medicine and Surgery, Respiratory Disease and Lung Function Unit, University of Parma, Parma, Italy; 2Department of Pediatrics, Cystic Fibrosis Center, University Hospital, Parma, ItalyCorrespondence: Luigino CalzettaDepartment of Medicine and Surgery, Respiratory Disease and Lung Function Unit, University of Parma, Viale A. Gramsci, 14, Parma, 43126, ItalyEmail [e-mail]: Smoking-induced bronchiolitis with progressive small airway dysfunction (SAD) is a leading cause of chronic obstructive pulmonary disease. We investigated the value of using the impulse oscillometry system (IOS) to detect SAD in asymptomatic smokers with preserved spirometry.Patients and Methods: We included 75 asymptomatic smokers (37 females, mean age 47± 12 years, 26± 17 pack/year) with preserved spirometry [forced expiratory volume at 1st second (FEV1)/forced vital capacity (FVC) ≥ 0.70 and normal FVC] and 34 never-smokers (19 females, mean age 42± 15 years).Results: In smokers, pack/years were significantly related to spirometry and IOS parameters (p < 0.05). The values of the fall in resistance from 5 Hz to 20 Hz (R5 – R20) were significantly and inversely related to the values of the ratio of forced expiratory volume in 3 and in 6 seconds (FEV3/FEV6) (p < 0.05). In addition, the percentage of heavy smokers (≥ 30 pack/year) with R5 – R20 > 0.07 kPa·s·L− 1, considered as IOS index of SAD, but not with FEV3/FEV6 less than a lower limit of normal, a spirometry index of SAD, was significantly higher than that of mild smokers (< 30 pack/year) and never-smokers (p < 0.05).Conclusion: This study demonstrates that IOS has the potential to detect SAD in asymptomatic heavy smokers with preserved spirometry and with FEV3/FEV6 values in the normal range. We confirm that IOS provides parameters which can complement traditional measurements of pulmonary function.Keywords: small airway dysfunction, impulse oscillometry system, spirometry, smokers, COPD