Impulse oscillometry for detection of small airway dysfunction in subjects with chronic respiratory symptoms and preserved pulmonary function

Abstract

Background Subjects with chronic respiratory symptoms and preserved pulmonary function (PPF) may have small airway dysfunction (SAD). As the most common means to detect SAD, spirometry needs good cooperation and its reliability is controversial. Impulse oscillometry (IOS) may complete the deficiency of spirometry and have higher sensitivity. We aimed to explore the diagnostic value of IOS to detect SAD in symptomatic subjects with PPF. Methods The evaluation of symptoms, spirometry and IOS results in 209 subjects with chronic respiratory symptoms and PPF were assessed. ROC curves of IOS to detect SAD were analyzed. Results 209 subjects with chronic respiratory symptoms and PPF were included. Subjects who reported sputum had higher R5–R20 and Fres than those who didn’t. Subjects with dyspnea had higher R5, R5–R20 and AX than those without. CAT and mMRC scores correlated better with IOS parameters than with spirometry. R5, R5–R20, AX and Fres in subjects with SAD (n = 42) significantly increased compared to those without. Cutoff values for IOS parameters to detect SAD were 0.30 kPa/L s for R5, 0.015 kPa/L s for R5–R20, 0.30 kPa/L for AX and 11.23 Hz for Fres. Fres has the largest AUC (0.665, P = 0.001) among these parameters. Compared with spirometry, prevalence of SAD was higher when measured with IOS. R5 could detect the most SAD subjects with a prevalence of 60.77% and a sensitivity of 81% (AUC = 0.659, P = 0.002). Conclusion IOS is more sensitive to detect SAD than spirometry in subjects with chronic respiratory symptoms and PPF, and it correlates better with symptoms. IOS could be an additional method for SAD detection in the early stage of diseases.

The Value of Fractional Exhaled Nitric Oxide and Impulse Oscillometric and Spirometric Parameters for Predicting Bronchial Hyperresponsiveness in Adults with Chronic Cough

“…Li et al reported that among IOS parameters, AX and Fres are associated with asthma. 15 Similarly, our study revealed significant differences in Fres, X5 and AX between the two groups. X5 is defined as the peripheral elastic resistance.…”

“… 32 In contrast, IOS might be a useful method for detecting SAD in subjects with chronic respiratory symptoms because of its higher sensitivity. 15 It seems that IOS has certain value in predicting BHR. Li et al reported that among IOS parameters, AX and Fres are associated with asthma.…”

“…18 Importantly, IOS distinguishes SAD from large airway obstruction and is more sensitive than spirometry in detecting peripheral airway diseases. 15 , 18…”

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

“…In addition, in subjects with chronic respiratory symptoms and normal spirometry, IOS was more sensitive in revealing SAD and correlated better with symptoms than spirometry. 15 In patients with COPD, IOS parameters showed a better correlation with small airway changes assessed by endo-bronchial optical coherence tomography than spirometry. 16 In asthmatic patients with normal FEV1 values, IOS revealed SAD, which was found to be associated with poor disease control and a history of asthma exacerbations.…”

“…Previous studies showed that spirometry was less sensitive in detecting both small and large airway dysfunction, as compared to IOS across a broad spectrum of clinical and research settings. 5,[14][15][16][17] In a cohort of ironworkers exposed to the catastrophic events at the World Trade Center (WTC), Skloot et al 14 showed that IOS revealed airway obstruction, expressed by abnormal R5 value, in 53% of subjects, while spirometry identified obstruction, defined by FEV1/FVC ≤ 0.70 and FEV1< 80% pred, in only 17% of subjects. Tellingly, in symptomatic individuals with WTC dust/fume exposure and normal For personal use only.…”