Impulse Oscillometry is Useful in Detecting Lung Function Abnormalities in Preschoolers with Primary Ciliary Dyskinesia but Not Cystic Fibrosis: A Cross-Sectional Study Results

<b><i>Background:</i></b> Although the forced oscillation technique has been used for many years in children, there is still inconclusive results about its efficiency in cystic fibrosis (CF). Moreover, no studies have been conducted on impulse oscillometry (IOS) in children with primary ciliary dyskinesia (PCD). <b><i>Methods:</i></b> Age, sex, weight, height, body mass index, and oscillometric parameters were compared in 3-6-year-old children with CF and PCD and healthy children. <b><i>Results:</i></b> This prospective study included 27 children with CF, 21 with PCD, and 27 healthy children, with mean ages of 4.11 ± 1.08, 4.33 ± 1.23, and 4.41 ± 0.79 years, respectively. No significant differences were revealed in the comparison of the z-scores of the parameters of the CF group with those of the healthy group. However, in the PCD group, z-scores of R5 and Z5 were significantly higher than those in the healthy group (<i>P</i> = 0.018 and <i>P</i> = 0.008, respectively). In addition, z-scores of X10, X15, and X20 were significantly lower in children with PCD compared with the healthy group (<i>P</i> = 0.013, <i>P</i> = 0.033, and <i>P</i> = 0.029, respectively). <b><i>Conclusions:</i></b> This first study simultaneously reporting IOS results in preschool children with CF or PCD showed a significant difference of resistance and reactance of airways between PCD and healthy children. This study is also very significant in showing that IOS can be performed in young children who are unable to cooperate with spirometry. In contrast, no such differences were noted between CF and healthy controls, possibly due to thick mucus affecting sound wave transmission through the airways in CF. In addition, IOS may be less effective in detecting early pulmonary disease, as in some studies it failed to identify abnormalities in young children with CF even when spirometry is abnormal.