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Variability in measures of exhaled breath Na+ and K+, influence of cardiac output and saliva
Author(s) -
Cassuto Nicholas A.,
Wheatley Courtney M.,
FoxxLupo William T.,
Snyder Eric M.
Publication year - 2009
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.23.1_supplement.lb169
Subject(s) - saliva , exhaled breath condensate , cystic fibrosis , exhaled air , medicine , exhalation , gastroenterology , exhaled nitric oxide , chemistry , asthma , anesthesia , spirometry , biology , toxicology
The assessment of inflammatory markers, ions, and cations in exhaled breath condensate (EBC) is being used more frequently in diseases such as asthma and cystic fibrosis. Previous work has demonstrated significant variability in the measures of exhaled Na+ and K+ in healthy subjects and in patients with cystic fibrosis. We sought to determine if the previously‐described variability in exhaled Na+ and K+ was due to differences in cardiac output (Q) or saliva Na+. To determine this, we collected EBC three times over 1.5hrs with the simultaneous sampling of saliva Na+ and assessment of Q (using acetylene rebreathing) in 7 healthy subjects (age=25±4yrs., ht.=177±7cm, wt.=70±25kg, BMI=22±7kg/m2). Exhaled Na+ averaged 2.1±0.8mmol/l and exhaled K+ averaged 0.14±0.04mmol/l. The coefficients of variation for exhaled ions across three measures averaged 30% for exhaled Na+ and 32% for exhaled K+. Within subjects, the relationship (Pearson correlation) between exhaled Na+ and K+ with Q averaged 0.61 and 0.45, respectively, and the relationship between exhaled Na+ with saliva values averaged 0.85 (p<0.05). Between subjects, the relationship between exhaled Na+ and K+ with Q averaged 0.52 and 0.38 (p<0.05 for both), respectively, and that between exhaled Na+ with saliva values averaged 0.72 (p<0.05). These results suggest that both cardiac output and saliva may contribute to the variability in exhaled ion measurement.