Comparison Of Two Devices And Two Breathing Patterns For Exhaled Breath Condensate Sampling

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Background: Analysis of exhaled breath condensate (EBC) provides a non-invasive access to the lung epithelial lining fluid. Aim: Comparison of two commercially available portable devices (RTube, ECoScreen turbo), and evaluation of different breathing patterns with regard to marker proteins and the source of EBC in healthy subjects. Methods: EBC was collected from 10 subjects 4 times in a cross-over design, for each device once during tidal breathing and once hyperventilating. Conductivity, pH, surfactant protein-A (SP-A), clara-cell protein (CCP) and total protein in EBC were assessed. Data on the volatile organic compound (VOC) profile of the EBC were obtained using the electronic nose Cyranose 320TM. Results: RTube provided a higher sample volume compared to the EcoScreen. Hyperventilation yielded higher volumes than tidal breathing. Neither devices nor breathing patterns affected pH. Although conductivity appeared to be affected by both, average measurements remained rather stable. Hyperventilation led to an increase of total protein. The ECoScreen showed a trend towards higher protein amounts. CCP and SP-A amounts were not influenced by the breathing pattern. The electronic nose was capable of distinguishing between breathing patterns and devices. Conclusion: EBC pH and (to a lesser extent) conductivity are fairly stable measures that do not depend on device or breathing pattern. Hyperventilation increases total protein concentration possibly via augmented shear forces and increased aerosol production, but not through increased alveolar ventilation, as SP-A amounts were not altered by hyperventilation. The VOC content of EBC seems to be influenced by device and breathing pattern.