RT Journal Article
SR Electronic
T1 Effect of reporting two versus three trials on lung clearance index values
JF European Respiratory Journal
JO Eur Respir J
FD European Respiratory Society
SP OA1792
DO 10.1183/1393003.congress-2017.OA1792
VO 50
IS suppl 61
A1 Klingel, Michelle
A1 Stanojevic, Sanja
A1 Jensen, Renee
A1 Rosenfeld, Margaret
A1 Davis, Stephanie
A1 Ratjen, Felix
A1 Retsch-Bogart, George
YR 2017
UL https://publications.ersnet.org//content/50/suppl_61/OA1792.abstract
AB Introduction: Currently, it is recommended that the lung clearance index (LCI) be reported as the average from three technically acceptable multiple breath washout (MBW) trials (Robinson et al., ERJ 2013). The objective of this study was to determine whether reporting two trials produces similar LCI results to three trials.Methods: MBW data collected using the Exhalyzer D® (EcoMedics AG, Switzerland) from one longitudinal study and one multi-centered interventional study were used for this analysis. Both studies requested MBW operators to collect at least three trials at each visit. All MBW data were over-read for technical quality by experienced reviewers. Success rates, average LCI, and the % coefficient of variation (CV) of LCI were compared using two or three trials as acceptability criteria.Results: Data included 1385 visits from 294 children aged 2.5-11 years in the two studies. Overall success was higher with two trials (84.6%) than three trials (60.4%) (Δ 24.2%; 95% CI 21.0, 27.4%; p<0.001). For test occasions with three acceptable trials (n=835), mean (SD) LCI was similar if two or three trials were included (8.4 vs 8.4; Δ 0.0; 95% CI -0.1, 0.2; p=0.79). The % CV was lower using two trials (4.5 vs 5.1, Δ -0.6; 95% CI -1.1, -0.1; p=0.01).Conclusion: Reporting LCI results from at least two technically acceptable trials allows for over 20% more visits to be included in analysis without affecting the value or the precision of the LCI.