TY - JOUR T1 - Lung clearance index during pulmonary exacerbation in school-age children with cystic fibrosis JF - European Respiratory Journal JO - Eur Respir J VL - 42 IS - Suppl 57 SP - P3608 AU - Liam Welsh AU - Marisol Tomai AU - Haily Tran AU - Sarath Ranganathan Y1 - 2013/09/01 UR - http://erj.ersjournals.com/content/42/Suppl_57/P3608.abstract N2 - Background Multiple breath washout is now regarded as a more sensitive measure of early cystic fibrosis (CF) lung disease than traditional measures of lung function. However, although it is well established that lung clearance index (LCI) is often abnormal in CF, it remains unclear what constitutes a clinically significant change.Methods We are prospectively performing multiple breath nitrogen washout (MBNW) and spirometry upon admission and at discharge in school-age children with CF who have been hospitalised for pulmonary exacerbation. Our aim is to establish the utility of LCI for assessing short term clinical response to IV therapy.Results Seven patients (4 male) with a mean (range) age of 15.6 (10.4 – 19.9) years, have completed paired MBNW measurements thus far in 2013. Mean (SD) LCI on admission was 11.18 (2.85) versus 9.90 (2.5) on discharge. Although this was a reduction of 10.7% the mean LCI did not differ significantly (p=0.308). The mean interval between MBNW measurements was 7.7 (3.9) days. Mean (SD) FEV1 % predicted on admission was 68.1 (16.2) % versus 73.1 (18.2) % at discharge, (p=0.08).Conclusion In this group of patients with mild-to-moderate CF lung disease, LCI improved by 10.7% over the course of their hospital admission while FEV-1 improved by 7.3%. As these lung function tests assess different aspects of lung disease, further data will allow both clinically significant cutoff values and the relative contributions of ventilation inhomogeneity and airway function during pulmonary exacerbations in CF to be determined. ER -