The Effect of Different Periods of Argon Deaeration on Exhaled Breath Condensate pH

Abstract

Background. Exhaled breath condensate (EBC) pH has been considered as a biomarker of airway inflammation in asthma. However, little information is available on the duration of argon deaeration required to achieve a stable pH in EBC samples. Objective. To identify differences in EBC pH after argon deaeration for 2, 4, and 8 min. Methods. EBC pH was determined in EBC samples from 48 subjects with allergic rhinitis (11 asthmatics) and 14 healthy volunteers without deaeration and after argon deaeration for 2, 4, and 8 min. Results. The mean (95% CI) pH values obtained from samples analyzed after 4 min [7.66 (7.52–7.80)] and 8 min [7.70 (7.55–7.85)] of argon deaeration were significantly less acidic (p < .001) than those identified after 2 min of deaeration [7.53 (7.40–7.66)]; differences between pH values at 4 and 8 min were not significant. Furthermore, changes in EBC pH of nondeaerated samples after 4 and 8 min of deaeration were significantly greater than those after 2 min, the mean difference being 0.11 (95% CI, 0.02–0.20, p < .05) and 0.13 (95% CI, 0.04–0.22, p < .01), respectively; differences between changes at 4 and 8 min were not significant. Conclusions. Stabilization of EBC pH is achieved after argon deaeration for 4 min. Therefore, this deaeration period may be recommended instead of the 7–8 min used in several studies.

• allergic rhinitis
• argon deaeration
• asthma
• exhaled breath condensate
• pH

Acknowledgments

The authors thank Christian Solomon for his help with English language.

Declaration of Interest

The authors report no conflict of interests. The authors alone are responsible for the content and writing of the paper.