Other Exhaled Markers

The use of exhaled breath condensates for assessing lung inflammation is complicated by dilution from varying amounts of water vapor. In 18 healthy subjects, Effros determined whether conductivity of lyophilized samples can be used for estimating airway electrolyte concentrations and dilution of exhaled condensates by water vapor. The dilution was estimated by comparing concentrations of nonvolatile, reference indicators (total nonvolatile cations, urea, or conductivity), and by assuming that concentrations in respiratory fluid and plasma are equivalent. The volatile cation, NH₄⁺, represented 93% of cations in the condensate. More than 99% of NH₄⁺ was removed by lyophilization, making it possible to use conductivity to estimate total nonvolatile ionic concentrations and facilitating analysis of urea. Estimates of dilution were equivalent for total cations (20,472), conductivity (21,019), and urea (18,818). The authors conclude that measurement of conductivity in lyophilized samples of exhaled breath condensates makes it possible to estimate the dilution of condensates by water vapor.

Because an imbalance between oxidant and antioxidants is implicated in the pathogenesis of asthma, Corradi and coworkers obtained exhaled breath condensates in 12 children with an exacerbation of asthma (mean, 11 years). Malondialdehyde, an oxidant, was higher in children with asthma than in control subjects, 30.2 versus 19.4 nM; malondialdehyde was reduced to 18.5 nM by 5 days of prednisone. Glutathione, an antioxidant, was lower in children with asthma than in control children, 6.0 versus 14.1 nM; glutathione was increased to 8.4 nM after treatment with oral prednisone. In the overall group (both patients and control subjects), glutathione and malondialdehyde were negatively correlated (r = -0.50). The authors conclude that aldehydes and glutathione are measurable in exhaled breath condensates in children with asthma, and are modified by an acute exacerbation and by treatment with prednisone. An editorial commentary by Gaston accompanies this article.

Citations 1-3 of 3 total displayed.

A Simple Method for Estimating Respiratory Solute Dilution in Exhaled Breath Condensates

Richard M. Effros, Julie Biller, Bradley Foss, Kelly Hoagland, Marshall B. Dunning, Daniel Castillo, Mark Bosbous, Feng Sun, and Reza Shaker
Am. J. Respir. Crit. Care Med. 168: 1500 -1505. First published online as doi:10.1164/rccm.200307-920OC [Abstract] [Full text]

Breath Condensate Analysis: Perhaps Worth Studying, After All

Benjamin Gaston
Am. J. Respir. Crit. Care Med. 167: 292-293. [Full text]

Aldehydes and Glutathione in Exhaled Breath Condensate of Children with Asthma Exacerbation

Massimo Corradi, Giuseppina Folesani, Roberta Andreoli, Paola Manini, Alessandro Bodini, Giorgio Piacentini, Silvia Carraro, Stefania Zanconato, and Eugenio Baraldi
Am. J. Respir. Crit. Care Med. 167: 395 -399. First published online as doi:10.1164/rccm.200206-507OC [Abstract] [Full text]

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