Spirometry and respiratory oscillometry: Feasibility and concordance in schoolchildren with asthma

Abstract

Objective The purpose of this study was to describe the feasibility of respiratory oscillometry (RO) in schoolchildren with asthma, and the concordance of its results with those of spirometry, to determine its clinical usefulness. Methods RO and spirometry were performed in 154 children (6 to 14‐year‐old) with asthma, following strict quality criteria for the tests. Their feasibility (probability of valid test, time of execution, number of maneuvers needed to achieve a valid test, and perceived difficulty) was compared. The factors that influence feasibility were analyzed with multivariate methods. FEV1, FEV1/FVC, FVC and FEF25‐75 for spirometry, and R5, AX and R5‐19 for RO, were converted into z‐scores and their concordance was investigated through intraclass correlation coefficients (ICC) and kappa indices for normal/abnormal values. Results There were no differences in the probability of obtaining a valid RO or spirometry (83.1% vs. 81.8%, p = 0.868). RO required a lower number of maneuvers [mean (SD) 4.2 (1.8) versus 6.0 (1.6), p < 0.001] and less execution time [5.1 (2.7) versus 7.6 (2.4) minutes, p < 0.001], and patients considered it less difficult. Age increased the probability of obtaining valid RO and spirometry. The concordance of results between RO and spirometry was low, and only between zFEV1 and zAX could it be considered moderate (ICC = 0.412, kappa = 0.427). Conclusion RO and spirometry are feasible in children with asthma. RO has some practical advantages, but the concordance of its results with spirometry is low.

The role of oscillometry in asthma

“…2[15,16]. However, there are some conflicting data on the correlation between spirometry and oscillometry, especially in children [17,18]. The lack of strong correlation can be partially explained by the fundamental differences between the two techniques since spirometry is performed by forced exhalation and oscillometry derives impedance during tidal breathing.…”

“…As stated previously, the variability in devices and lack of well established abnormal cut-offs may contribute to discrepancies between these studies. In the pediatric population where spirometry can be difficult to perform, oscillometry is more feasible but concordance with spirometry is low [17]. For children under the age of 5 years old, abnormal oscillometry predicted abnormal spirometry and bronchodilator response at school age [21 ▪ ], which suggests that oscillometry may predict the development of asthma in this population.…”

Predictive Value of Impulse Oscillometry Combined with Fractional Expiratory Nitric Oxide Test for Asthma in Preschool Children

“… 8 In comparison to spirometry, IOS requires fewer maneuvers, less execution time, and is more sensitive in differentiating asthmatic from non-asthmatic children. 9 , 10 According to the recommendations of the European Respiratory Society, IOS can be measured starting at 2 years of age. 11 In conclusion, IOS has important clinical value in the diagnosis of asthma and monitoring of pulmonary function in preschool children.…”