PT  - JOURNAL ARTICLE
AU  - Sophie Yammine
AU  - Florian Singer
AU  - Chiara Abbas
AU  - Philipp Latzin
TI  - Ways to shorten the lung clearance index measurement I - Are three measurements needed?
DP  - 2012 Sep 01
TA  - European Respiratory Journal
PG  - P4604
VI  - 40
IP  - Suppl 56
4099  - http://erj.ersjournals.com/content/40/Suppl_56/P4604.short
4100  - http://erj.ersjournals.com/content/40/Suppl_56/P4604.full
SO  - Eur Respir J2012 Sep 01; 40
AB  - Background Inert gas multiple-breath washout (MBW) derived lung clearance index (LCI) is a sensitive lung function parameter in subjects with mild cystic fibrosis (CF) lung disease, but rarely measured in clinical routine due to lack of available equipment and lengthy protocols. Using an available nitrogen (N2) MBW setup (Exhalyzer D, Eco Medics, Switzerland) we assessed shortened N2MBW protocols for LCI.Methods We determined whether the LCI from the 1st (LCI1) and the mean LCI of the 1st and 2nd valid N2MBW (LCI2), respectively, are comparable to the averaged information obtained from three N2MBW (LCI3). We analyzed data of 33 school-aged children with CF and 10 controls performing triplicate N2MBW.Results LCI1, LCI2, and LCI3 differed significantly between healthy and CF children. LCI1 and LCI2 were strongly associated with LCI3 (R2 = 0.98 for both), took less time, and were of similar diagnostic value. Comparing LCI1 and LCI2 with LCI3, mean (range) test duration was 2.2 (0.5-5.2), 6.6 (3.6-12.7), and 11.1 (8.0-17.1) min, and upper limits of normal LCI (8.3, 8.3, and 8.4) all correctly classified 71% of children, respectively. Bland-Altman analysis of LCI1 and LCI2 showed good agreement with LCI3: Mean difference was -1.1% and -0.7%, limits of agreement were 6.8 to -9.0% and 5.9 to -7.3%, respectively.Conclusion In the current study population, the 1st LCI or the mean of the 1st and 2nd LCI take less time and predict the mean LCI of three N2MBW within physiological measurement variability. Using less N2MBW measurements seems promising for time-saving LCI measurement in clinical routine.