The Lung Clearance Index (LCI) can recognize pulmonary ventilation inhomogeneity in preschool children with primary ciliary dyskinesia (PCD) who are as young as 2 years old, according to study findings recently published in Chest. The study results also suggest that “lung disease severity in PCD may be similar to that in CF [cystic fibrosis] during preschool years,” noted the study authors.

Previous studies have suggested that the LCI might offer the same kind of sensitive parameter for detecting lung function impairment in children with PCD as it does for those with CF. However, these earlier studies focused on children school-aged and older. To evaluate the feasibility of using the LCI in preschool children with PCD, the researchers studied preschoolers with PCD, preschoolers with CF, and a control group of healthy participants in a prospective, observational, cross-sectional study. LCI values were determined using nitrogen multiple breath washout (N2 MBW) testing, which assesses the homogeneity of lung ventilation. The results were compared among the 3 groups.

This multicenter study involved 101 preschool children in Germany and Poland. The nitrogen multiple breath washout was successful in 91 participants (90.1%). LCI values were obtained from 27 children with PCD, 34 children with CF, and 30 children in the control group (mean age, 4.8 years; range, 2.2-6.9 years). In preschoolers with PCD, LCI values were higher (median, 9.1; 95% CI, 8.6-10.3) than those of children in the control group (median, 7.0; 95% CI, 6.7-7.1; P <.0001) but did not differ from the values in preschool children with CF (median, 8.6; 95% CI, 8.4-9.7; P =.71). The feasibility in the PCD group was 93.1%, comparable to that found in the CF group (91.9%) and in children in the control group (85.7%; P =.55).


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The researchers found no evidence that age and pulmonary infection with proinflammatory pathogens affected the LCI. In their study cohorts, the LCI did not correlate with age. Within the PCD and CF groups, no significant difference in the LCI was noted between patients with proinflammatory bacterial infection and those without.

“This study demonstrated early onset of lung disease in preschool children with PCD,” said the authors, who added that their study demonstrated the feasibility of using MBW in preschoolers. “These data support a need for early diagnostic monitoring and therapy and suggest the LCI as a noninvasive diagnostic tool and as a potential end point in clinical trials testing early interventions in children with PCD,” the authors concluded.

The investigators added that a limitation of their study was the lack of pulmonary imaging data, which would have enhanced the interpretation of the elevated LCI values in terms of structural lung changes.

Disclosure: Multiple authors declared affiliations with the pharmaceutical industry. Please refer to the original article for a full list of disclosures.

Reference

Roehmel JF, Doerfler FJ, Koerner-Rettberg C, et al. Comparison of the lung clearance index in preschool children with primary ciliary dyskinesia and cystic fibrosis. Chest. Published online March 7, 2022. doi:10.1016/j.chest.2022.02.052