RT Journal Article SR Electronic T1 Infection and inflammation does not effect ventilation distribution in infants with cystic fibrosis (CF) JF European Respiratory Journal JO Eur Respir J FD European Respiratory Society SP 4657 VO 38 IS Suppl 55 A1 Shannon J. Simpson A1 Karla M. Logie A1 Sven Schulzke A1 Judy Park A1 Sarath Ranganathan A1 Stephen M. Stick A1 Graham L. Hall YR 2011 UL http://erj.ersjournals.com/content/38/Suppl_55/4657.abstract AB Introduction: Preschool and school aged children with CF have been reported to show an elevated lung clearance index (LCI), which further increases in the presence of Pseudomonas aeruginosa infection. In contrast, increased LCI is less prevalent in infants with CF. The aim of this study was to assess the impact of pulmonary infection and the presence of free neutrophil elastase (NE) as a marker of airway inflammation, on ventilation distribution in infants and children ≤ 2 years with CF.Methods: Multiple breath washout (MBW) using 5% SF6 and an ultrasonic flowmeter (Ecomedics, Switzerland) was performed 1-3 days prior to bronchoalveolar lavage (BAL) in 85 children. LCI and the 1st and 2nd moment ratio (M1/M0 and M2/M0) were determined from the washout. Generalised estimating equations with exchangeable working correlation structure were used to estimate linear regression coefficients. Adjustments were made for sex, height and functional residual capacity.Results: The presence of a pulmonary infection (n=13; ≥105 cfu.ml -1) had no impact on LCI (p=0.353), but did result in increased M1/M0 (p=0.027) and M2/M0 (p=0.052) when compared to un-infected infants (n=36). Children with P. aeruginosa (n=4) colonisation showed no altered MBW outcomes when compared to the un-infected group. Similarly, the presence of NE (n=14) was not associated with altered MBW outcomes.Conclusion: LCI in this group of children was not a sensitive measure of CF lung disease as indicated by free NE or endobronchial infection. Moment ratios appear to be more sensitive to lung disease associated with infection than LCI.