RT Journal Article
SR Electronic
T1 Hydrogen peroxide in exhaled air: A source of error, a paradox and its resolution
JF European Respiratory Journal
JO Eur Respir J
FD European Respiratory Society
SP P243
VO 40
IS Suppl 56
A1 Stefan Peters
A1 Angelika Kronseder
A1 Stefan Karrasch
A1 Petra Neff
A1 Matz Haaks
A1 Rembert Koczulla
A1 Dennis Nowak
A1 Rudolf Jörres
YR 2012
UL http://erj.ersjournals.com/content/40/Suppl_56/P243.abstract
AB Background: The concentration of hydrogen peroxide (H2O2) in exhaled air has been reported to be elevated in asthma and COPD, but the data are inconsistent and difficult to reproduce. Notably, a relevant concentration of H2O2 can be found in ambient air. Therefore, we examined the association between H2O2 in ambient and exhaled air.Methods: Exhaled breath condensate (EBC) of 12 COPD patients and 9 healthy subjects was collected with an inhalation filter (F; efficiency 81%) or without (nF). Ambient air condensate (AAC) was collected in parallel and all samples were analysed for H2O2. Additionally, ambient H2O2 concentration was recorded by an analyser for atmospheric H2O2.Results: H2O2 concentration in AAC (3.60±1.40µM, mean±SD) was higher (p<0.01) than in EBC (Table). It showed meteorological variations concordant with atmospheric measurements. In both groups studied, the inhalation filter caused a reduction of H2O2 values (p<0.01). Despite the comparatively low levels in exhaled air, analysis by means of a mathematical model revealed an endogenous H2O2 contribution which was more pronounced when using the inhalation filter.View this table:Conclusion: The paradox of low H2O2 values in exhaled air assessed by EBC dissolves when taking into account the reconditioning of inhaled air containing H2O2. This may partially explain the heterogeneity of study results and their limited reproducibility. Still, there seems to be endogenous H2O2 production but its valid determination requires inhalation filters. This suggests a reanalysis of studies from the literature.