Breath Condensate as a Vehicle for Collection of Inflammatory Mediators, Especially Hydrogen Peroxide

Exhaled air is saturated with water at 37�C, and cooling causes condensation of this water vapor. Breath condensate can be analyzed for the presence of inflammatory mediators and other putative markers of inflammation, among which are hydrogen peroxide (H₂ O₂ ), leukotrienes (LT), prostanoids, thiobarbituric acid reactive products (TBARs), and metabolites of nitric oxide (NO), including nitrites and nitrates. The methodology for these measurements has not been standardized. There is very little, if any, direct evidence that concentrations of substances detected in breath condensate actually reflect their concentration at the level of the intrapulmonary airways. However, studies that have correlated breath condensate findings to the presence and severity of lower airway disease suggest that this might be the case.