%0 Journal Article %A Noor AL-Khathlan %A Erol Gaillard %A Caroline Beardsmore %T Lung clearance index (LCI) and hyperinflation in children with cystic fibrosis (CF) %D 2012 %J European Respiratory Journal %P P1451 %V 40 %N Suppl 56 %X Introduction: LCI is used to detect early CF lung disease.1,2,3 However, there are few data relating changes in LCI to lung volumes, and extent of hyperinflation, in children with CF.1 Therefore, we aimed to look at the association between LCI derived from multiple-breath nitrogen washout (MBNW) and two indices of hyperinflation (i) residual volume/total lung capacity (RV/TLC), and (ii) the difference between FRC determined by plethysmography (FRCp) and MBNW (FRCN2).Methods: Children with CF completed MBNW and plethysmography as part of their annual review. All tests were performed, analysed and reported according to ATS/ERS recommendations. The difference between FRCp and FRCN2 was expressed as a % of FRCp and called FRCdiff. Results were examined using Spearman's rank correlation coefficient.Results: 37 children with CF (aged 5-17) completed lung function tests. A significant correlation was found between LCI and RV/TLC (r=0.516, p=0.001)(Figure), and between LCI and FRCdiff (r=0.413, p=0.011).Discussion: The adoption of LCI as an ideal marker for early lung disease requires that it should correspond to established markers of abnormalities in lung function.2 Our findings showed comparable decline in LCI and indices of hyperinflation in children with CF.References:1. Horsley, A. et al. 2008; Respir Physiol and Neurobiology; 162: 197-2032. Aurora, P. 2010; Thorax; 65: 373-3743. Gustafsson et al. 2008; Thorax 2008 63: 129-134. %U https://erj.ersjournals.com/content/erj/40/Suppl_56/P1451.full.pdf