Faculty Collaboration Database

The effects of volatile salivary acids and bases on exhaled breath condensate pH. Am J Respir Crit Care Med 2006 Feb 15;173(4):386-92

Date

11/15/2005

Pubmed ID

16284109

Pubmed Central ID

PMC2662940

DOI

10.1164/rccm.200507-1059OC

Scopus ID

2-s2.0-32444434383 (requires institutional sign-in at Scopus site)   94 Citations

Abstract

RATIONALE: Recent studies have reported acidification of exhaled breath condensate (EBC) in inflammatory lung diseases. This phenomenon, designated "acidopnea," has been attributed to airway inflammation.

OBJECTIVES: To determine whether salivary acids and bases can influence EBC pH in chronic obstructive pulmonary disease (COPD).

METHODS: Measurements were made of pH, electrolytes, and volatile bases and acids in saliva and EBC equilibrated with air in 10 healthy subjects and 10 patients.

RESULTS: The average EBC pH in COPD was reduced (normal, 7.24 +/- 0.24 SEM; range, 6.11-8.34; COPD, 6.67 +/- 0.18; range, 5.74-7.64; p = 0.079). EBCs were well buffered by NH(4)(+)/NH(3) and CO(2)/HCO(3)(-) in all but four patients, who had NH(4)(+) concentrations under 60 micromol/L, and acetate concentrations that approached or exceeded those of NH(4)(+). Saliva contained high concentrations of acetate (approximately 6,000 micromol/L) and NH(4)(+) (approximately 12,000 micromol/L). EBC acetate increased and EBC NH(4)(+) decreased when salivary pH was low, consistent with a salivary source for these volatile constituents. Nonvolatile acids did not play a significant role in determining pH of condensates because of extreme dilution of respiratory droplets by water vapor (approximately 1:12,000). Transfer of both acetic acid and NH(3) from the saliva to the EBC was in the gas phase rather than droplets.

CONCLUSIONS: EBC acidification in COPD can be affected by the balance of volatile salivary acids and bases, suggesting that EBC pH may not be a reliable marker of airway acidification. Salivary acidification may play an important role in acidopnea.

Author List

Effros RM, Casaburi R, Su J, Dunning M, Torday J, Biller J, Shaker R

Author

Reza Shaker MD Assoc Provost, Sr Assoc Dean, Ctr Dir, Chief, Prof in the Medicine department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Acetic Acid
Acid-Base Equilibrium
Breath Tests
Exhalation
Female
Humans
Hydrogen-Ion Concentration
Male
Middle Aged
Pulmonary Disease, Chronic Obstructive
Quaternary Ammonium Compounds
Saliva