TY - JOUR T1 - Double-tracer gas single breath washout - Variability and reproducibility compared with classical nitrogen washout tests JF - European Respiratory Journal JO - Eur Respir J VL - 42 IS - Suppl 57 SP - P3939 AU - Kim Husemann AU - Nina Berg AU - Jennifer Engel AU - Johannes Port AU - Christoph Joppek AU - Ziran Tao AU - Holger Schulz AU - Martin Kohlhäufl Y1 - 2013/09/01 UR - http://erj.ersjournals.com/content/42/Suppl_57/P3939.abstract N2 - BackgroundInert tracer gas washout tests are noninvasive tools to assess ventilation inhomogeneity in small airway diseases. Multiple breath washouts (MBW) are time consuming, single breath washouts (SBW) require a difficult breathing maneuver. We want to assess feasibility, variability and reproducibilitiy of a new fast and easy double tracer gas single breath washout (DTG-SBW)1 and compare this test with conventional nitrogen (N2) washouts.Materials and methodsIn 40 healthy nonsmokers (n = 20 ≤ 40, n = 20 > 40 years) we performed a triplet of N2-SBW, N2-MBW and tidal DTG-SBW. Follow up was after 1 week and 1 month. We measured the lung clearance index LCI (N2-MBW), slope of phase III dN2 (N2-SBW) and DTG-slope III (DTG-SBW) calculated with a new automated algorhythm.ResultsMean (SD) LCI at baseline was 6.93 (0.61), mean (SD) dN2 0.99 (0.42) %N2/L and mean (SD) DTG-slope III -0.207 (0.106) g/mol*L. LCI showed a statistically significant difference between younger and older subjects (mean LCI (SD) 6.62 (0.37) ≤ 40 years vs. 7.25 (0.64) > 40 years, p < 0.001). The mean intra-test coefficient of variation for three single measurements was 4.1% for LCI, 15.7% for dN2 and 22.6 % for DTG-Slope-III. The mean difference between tests was small for all three washouts – considering short term (1st vs. 2nd) as well as long term reproducibility (1st vs 3rd test).ConclusionVariability of the DTG-SBW is acceptable, reproducibility is good and comparable with standard nitrogen washout tests. The fast and easy DTG-SBW with new automated analysis may be applicable for diagnosis and assessment of small airway diseases.Reference1 Singer F et al. PLoS ONE 2011; 6: e17588. ER -