Exhaled Markers

In 20 patients with COPD (FEV₁, 52% of predicted), 20 nonsmoking control subjects, and 12 smoking control subjects, Corradi and coworkers studied different classes of aldehydes in exhaled breath condensates. Compared with nonsmoking control subjects, the patients had higher levels of malondialdehyde (57.2 versus 17.7 nmol per liter), hexanal (63.5 versus 14.2 nmol per liter), and heptanal (26.6 versus 18.7 nmol per liter). Only malondialdehyde was higher in the patients than in smoking control subjects (57.2 versus 35.6 nmol per liter). The authors conclude that malondialdehyde, hexanal, and heptanal are higher in exhaled breath condensate of patients with COPD than in nonsmoking control subjects, but only malondialdehyde is higher in patients than in smoking control subjects. An editorial commentary by Risby accompanies this article.

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 assuming that concentrations in respiratory fluid and plasma are equivalent. The volatile cation, ammonium (NH₄⁺), represented 93% of cations in the condensate. More than 99% of ammonium 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.

To measure fractions of exhaled nitric oxide in intubated, mechanically ventilated patients, Tornberg and coworkers developed a method for obtaining multiple single-breath measurements at preset expiratory flows. A suction ejection system connected to a restriction valve was used to obtain multiple single-breath exhalations. Intubation produced a 50% decrease in the fraction of exhaled nitric oxide and a 36% decrease in the airway wall transfer rate of nitric oxide. Neither the fraction of nitric oxide originating in alveoli or in airway wall epithelium was affected by intubation. The peak concentration of nitric oxide after 20 seconds of apnea was similar to the value of nitric oxide calculated as originating in the airway wall epithelium. The authors conclude that the vacuum aspiration method for multiple single-breath measurements in mechanically ventilated patients enables the calculation of alveolar and bronchial fractions of nitric oxide.

To determine whether variables measured from exhaled condensates are influenced by presence or absence of a nose clip, Vass and coworkers studied 25 healthy volunteers and 8 patients with allergic rhinitis. The volume of condensate was higher when subjects inhaled and exhaled through the mouth (with a nose clip) than when they inhaled through the nose and exhaled through the mouth (without nose clip): 2,321 versus 1,746 ľl. Levels of adenosine, ammonia, and thromboxane B₂ were equivalent by the two routes in both healthy subjects and patients with rhinitis. The authors conclude that use of a nose clip results in an exhaled condensate of greater volume, but it does not influence the level of inflammatory mediators.

Citations 1-5 of 5 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]

Multiple Single-breath Measurements of Nitric Oxide in the Intubated Patient

Daniel C. Törnberg, Håkan Björne, Jon O. Lundberg, and Eddie Weitzberg
Am. J. Respir. Crit. Care Med. 168: 1210 -1215. First published online as doi:10.1164/rccm.200306-784OC [Abstract] [Full text]

Further Discussion on Breath Condensate Analysis

Terence H. Risby
Am. J. Respir. Crit. Care Med. 167: 1301-1302. [Full text]

Aldehydes in Exhaled Breath Condensate of Patients with Chronic Obstructive Pulmonary Disease

Massimo Corradi, Israel Rubinstein, Roberta Andreoli, Paola Manini, Andrea Caglieri, Diana Poli, Rossella Alinovi, and Antonio Mutti
Am. J. Respir. Crit. Care Med. 167: 1380 -1386. First published online as doi:10.1164/rccm.200210-1253OC [Abstract] [Full text]

Comparison of Nasal and Oral Inhalation during Exhaled Breath Condensate Collection

Géza Vass, Éva Huszár, Erzsébet Barát, Márta Valyon, Domonkos Kiss, István Pénzes, Mónika Augusztinovicz, and Ildikó Horváth
Am. J. Respir. Crit. Care Med. 167: 850 -855. First published online as doi:10.1164/rccm.200207-716BC [Abstract] [Full text]

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