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Comparison of lung clearance index measured during helium washin and washout in children with cystic fibrosis
Author(s) -
Vermeulen François,
Ophoff Jill,
Proesmans Marijke,
De Boeck Kris
Publication year - 2013
Publication title -
pediatric pulmonology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.866
H-Index - 106
eISSN - 1099-0496
pISSN - 8755-6863
DOI - 10.1002/ppul.22719
Subject(s) - medicine , cystic fibrosis , washout , nitrogen washout , lung , repeatability , gastroenterology , lung volumes , functional residual capacity , chemistry , chromatography
Aim Lung clearance index (LCI) is a sensitive marker of early lung disease in cystic fibrosis (CF). This preliminary study compares results obtained from the washin and the washout phase of the multiple breath washout in CF children and healthy controls using an early commercially available device. Methods LCI was measured using a device measuring flow and mainstream molar mass with helium as the inert gas. Sixty‐five healthy controls and 65 CF children (age range 4.6–17.9 years) were included. Results LCI measured on the washout (LCI WO ) and on the washin (LCI WI ) were correlated in CF children (R = 0.440, P < 0.001, n = 185). LCI WO was higher than LCI WI with a mean difference of 1.08 (95% limits of agreement −2.11 to 4.27, n = 185) in CF children and 0.26 (95% LA −3.2 to 3.72, n = 185) in controls. Within‐test repeatability criteria were met in 107/130 WO and 93/130 WI ( P = 0.034), In 81 children, LCI WI and LCI WO were obtained. LCI WI was higher in CF patients than in controls (7.72 vs. 6.55, P < 0.001), as was LCI WO (8.49 vs. 7.13, P < 0.001). In 34 CF patients with normal FEV 1 , LCI WI only was abnormal in five, LCI WO only in five and both were abnormal in three. One of seven CF patients with abnormal FEV 1 had normal LCI WI and LCI WO . Conclusion In CF patients, discordances between abnormal LCI WI and LCI WO were observed. LCI WI and LCI WO were only weakly correlated. This likely resulted from technical factors as the use of mainstream molar mass signal, a temperature model validated for infants only and absence of CO 2 correction. Pediatr Pulmonol. 2013; 48:962–969. © 2013 Wiley Periodicals, Inc.