Effects of breathing pattern and inspired air conditions on breath condensate volume, pH, nitrite, and protein concentrations

Abstract

Background: The effects of breathing pattern and inspired air conditions on the volume and content of exhaled breath condensate (EBC) were investigated. Methods: Total exhaled water (TEW), EBC volume, pH, nitrite and protein concentrations were measured in three groups of 10 healthy subjects breathing into a condenser at different target minute ventilations (Vm), tidal volumes (Vt), and inspired air conditions. Results: The volumes of both TEW and EBC increased significantly with Vm. For Vm 7.5, 15 and 22.5 l/min, mean (SD) EBC was 627 (258) μl, 1019 (313) μl, and 1358 (364) μl, respectively (pv 30.7 μl/l, mean difference 4.1 (95% CI 2.6 to 5.6), pv 7.6 μl/l, mean difference 3.4 (95% CI 2.3 to 4.5), pConclusion: These results show that condensate volume can be increased by using high Vt and increased Vm without compromising the dilution of the sample.