PT  - JOURNAL ARTICLE
AU  - Anna Gensmer
AU  - Sylvia Nyilas
AU  - Michael Tamm
AU  - Philipp Latzin
AU  - Daiana Stolz
TI  - Single-breath washout in stable COPD patients: Association with bodyplethysmography and bronchodilator response
AID  - 10.1183/13993003.congress-2015.PA4621
DP  - 2015 Sep 01
TA  - European Respiratory Journal
PG  - PA4621
VI  - 46
IP  - suppl 59
4099  - http://erj.ersjournals.com/content/46/suppl_59/PA4621.short
4100  - http://erj.ersjournals.com/content/46/suppl_59/PA4621.full
SO  - Eur Respir J2015 Sep 01; 46
AB  - Background: Single-breath washout (SBW) has been shown to be feasible and reproducible in patients with stable chronic obstructive pulmonary disease (COPD). Whether these tests are useful to detect bronchodilator response and association with other lung function tests is unknown.Aims: We assessed the ability of SBW tests to detect bronchodilator response and compared them to conventional lung function tests in patients with COPD. Main outcome parameters are change in SlopeIII from vital capacity nitrogen (N2)-SBW (dN2), SlopeIII (SnIIIDTG) and Slope CO2(SIII-CO2DTG) from tidal double-tracer gas (DTG) SBW.Methods: 82 subjects (20 healthy nonsmokers and 62 COPD patients) performed three N2-SBW, three tidal helium and sulfur hexafluoride DTG-SBW tests and plethysmography pre and post bronchodilation. Natural variability and short term repeatability was determined in healthy controls (HC).Results: COPD patients showed significantly higher dN2 than HC (12.5 vs 0.9 %N2/l), SIII-CO2DTG (1.5 vs 0.5 %CO2) and steeper SnIIIDTG (-0.5 vs -0.2 g/mol); all p<0.001. Higher dN2 is significantly associated with lower FEV1 (R2=0.51), higher RV/TLC (R2=0.38) and lower DLCOcSB (R2=0.29); all p<0.001. Bronchodilation showed a significant effect for dN2 (12.5 to 13.8 %N2/l, p=0.02). 46 COPD patients showed a change greater than the coefficient of repeatability (CR) from HC for dN2 (13 improved, 33 deteriorated), 11 for SnIIIDTG (6 better, 5 worse) and 2 for SIII-CO2DTG.Conclusion: N2-SBW discriminates COPD patients and HC better than DTG-SBW, and shows a heterogeneous response to bronchodilator in COPD. N2-SBW in COPD patients is strongly associated with obstruction, emphysema and hyperinflation.