Related Experiment Video
Updated: May 18, 2026

Fast and Accurate Exhaled Breath Ammonia Measurement
Published on: June 11, 2014
Exhaled breath condensate pH is influenced by respiratory droplet dilution
Andras Bikov1, Gabriella Galffy, Lilla Tamasi
1Department of Pulmonology, Semmelweis University, Dios arok 1/C, Budapest, H-1125, Hungary.
Abstract:
Several studies support that airway acid stress plays a role in the pathophysiology of asthma. Exhaled breath condensate pH (EBC pH) was suggested as a surrogate marker of airway acidification. The dilution of airway lining fluid (ALF) acids and bases by alveolar water may influence condensate pH, but it has not been studied yet. The aim of our study was to investigate the relationship between EBC pH and ALF dilution in EBC samples obtained from asthmatic and healthy subjects. EBC was collected from 55 asthmatic and 57 healthy subjects for pH and conductivity measurements. Fractional exhaled nitric oxide (FE(NO)) and lung function tests were also performed in asthmatic patients. EBC pH was determined after 10 min of argon deareation and the dilution was estimated by the measurement of conductivity in vacuum-treated samples. There was no difference either in EBC pH or dilution between the two groups. However, a significant relationship was found between EBC pH and dilution in both groups (p < 0.05, r = -0.35 and r = -0.29, asthmatic and healthy groups, respectively). Our results suggest important methodological aspect indicating that EBC pH is affected by respiratory droplet dilution, and this effect should be taken into consideration when interpreting EBC pH data.
Related Concept Videos
Respiratory Regulation of Acid-Base Balance
When carbon dioxide levels increase in the blood, more H+ and HCO3⁻ are produced, leading to a...
Phase Transitions: Vaporization and Condensation
Microbiota of the Respiratory Tract
Physical Principles Governing Gas Exchange
Gas Laws Governing Respiration
The behavior of gases is guided by Dalton's Law of partial pressures and Henry's Law.
Dalton's Law asserts that the total pressure exerted by...
Pulmonary Cycle: Exhalation
Breathing

