title: Dilution of respiratory solutes in exhaled condensates.
abstract: Most exhaled water is produced as gaseous water vapor, which can be collected in cooled condensers. The presence of nonvolatile solutes in these condensates suggests that droplets of respiratory fluid (RF) have also been collected. However, calculation of RF solute concentrations from condensates requires estimation of the dilution of RF droplets by water vapor. We used condensate electrolyte concentrations to calculate the dilution of RF droplets in condensates from 20 normal subjects. The total ionic concentration (conductivity) was 497 plus minus 68 (mean plus minus SEM) muM. Of this, 229 plus minus 43 muM was NH(4)(+), but little NH(4)(+) was collected from subjects with tracheostomies, indicating oral formation. The Na+ concentration in condensate ([Na+](cond)) averaged 242 plus minus 43 muM. Large variations in [Na(+)](cond) correlated well with variations of K+ in condensate ([K+](cond)) and Cl-) in condensate ([Cl-](cond)), and were attributed to differences in respiratory droplet dilution. Dividing condensate values of ([Na+] + [K+] ) by those of plasma indicated that RF represented between 0.01% and 2.00% of condensate volumes. Calculated values for Na+, K+, Cl-, lactate, and protein in RF were [Na+](RF) = 91 +/- 8 mM, [K+](RF) = 60 +/- 11 mM, [Cl-](RF) = 102 +/- 17 mM, [lactate](RF) = 44 +/- 17 mM, and [protein](RF) = 7.63 +/- 1.82 g/dl, respectively.
authors.affiliation: Department of Medicine, Medical College of Wisconsin, 9200 West Wisconsin Ave., Milwaukee, WI 53226, USA. effros@mcw.edu
authors.forename: Richard M
authors.initials: RM
authors.lastname: Effros
authors.forename: Kelly W
authors.initials: KW
authors.lastname: Hoagland
authors.forename: Mark
authors.initials: M
authors.lastname: Bosbous
authors.forename: Daniel
authors.initials: D
authors.lastname: Castillo
authors.forename: Bradley
authors.initials: B
authors.lastname: Foss
authors.forename: Marshall
authors.initials: M
authors.lastname: Dunning
authors.forename: Meir
authors.initials: M
authors.lastname: Gare
authors.forename: Wen
authors.initials: W
authors.lastname: Lin
authors.forename: Feng
authors.initials: F
authors.lastname: Sun
mesh_terms: D000136:Acid-Base Equilibrium / Q000502:physiology*; D000328:Adult; D001944:Breath Tests / Q000379:methods*; D005260:Female; D006801:Humans; D018836:Inflammation Mediators / Q000032:analysis; D008171:Lung Diseases / Q000175:diagnosis* / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D029424:Pulmonary Disease, Chronic Obstructive / Q000175:diagnosis / Q000503:physiopathology; D012016:Reference Values; D020545:Respiratory Mucosa / Q000503:physiopathology*; D012680:Sensitivity and Specificity; D020181:Sleep Apnea, Obstructive / Q000175:diagnosis / Q000503:physiopathology; D014139:Tracheostomy; D014882:Water-Electrolyte Balance / Q000502:physiology*
chemical_list: D018836:Inflammation Mediators