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A simple method for estimating respiratory solute dilution in exhaled breath condensates
Richard M Effros1, Julie Biller, Bradley Foss
1Division of Pulmonary and Critical Care Medicine, Adult Cystic Fibrosis Center, Medical College of Wisconsin, Milwaukee, WI, USA. effros@mcw.edu
American Journal of Respiratory and Critical Care Medicine
|September 27, 2003
Summary
Exhaled breath condensate analysis is less invasive for lung disorders. Lyophilization removes volatile compounds, allowing conductivity to reliably estimate sample dilution for mediator analysis.
Area of Science:
- Pulmonary Medicine
- Biochemistry
- Analytical Chemistry
Background:
- Exhaled breath condensate (EBC) is a non-invasive tool for analyzing airway inflammation.
- EBC is diluted by water vapor, complicating the quantification of inflammatory mediators.
- Accurate assessment of EBC dilution is crucial for reliable biomarker detection.
Purpose of the Study:
- To develop and validate a method for estimating EBC dilution.
- To assess the utility of conductivity measurements for this purpose.
Main Methods:
- Compared nonvolatile indicators (cations, urea, conductivity) in EBC from healthy subjects.
- Assessed the impact of volatile ammonium (NH4+) on condensate composition.
- Utilized lyophilization to remove volatile NH4+ prior to analysis.
Main Results:
- Ammonium (NH4+) constituted over 93% of cations in EBC.
- Lyophilization effectively removed >99% of NH4+.
- Conductivity showed significant correlation with electrolyte and urea concentrations, and dilution estimates were comparable across methods.
Conclusions:
- Lyophilized EBC conductivity offers a simple, inexpensive, and reliable method to estimate dilution.
- This technique facilitates the accurate analysis of nonvolatile, hydrophilic mediators in EBC.
- Improved EBC analysis can aid in diagnosing and monitoring inflammatory lung disorders.