Comparison of nasal and oral inhalation during exhaled breath condensate collection.

Analysis of exhaled breath condensate is a method for noninvasive assessment of the lung. Condensate can be collected with a nose clip (subjects inhale and exhale via the mouth) or without it (subjects inhale via the nose and exhale via the mouth), but the mode of inhalation may influence condensate volume and mediator levels. We compared condensate volume and adenosine, ammonia, and thromboxane B2 levels in young healthy volunteers (n = 25) in samples collected for 10 minutes from subjects with or without a nose clip. Patients with allergic rhinitis (n = 8) were also studied to assess the effect of upper airway inflammation on mediator levels. Adenosine, ammonia, and thromboxane B2 levels were determined by HPLC, spectrophotometry, and radioimmunoassay, respectively. Volume of condensate was significantly higher without nose clip than that with nose clip (mean +/- SD, 2321 +/- 736 microl and 1746 +/- 400 microl, respectively; p = 0.0001). We found no significant difference in any mediator levels between these two collection modes in healthy volunteers, but adenosine showed a tendency to differ between oral and nasal inhalation in patients with allergic rhinitis. Our data indicate that whereas a greater volume of condensate can be obtained when subjects inhale through their noses, the mode of inhalation does not influence mediator levels in young healthy volunteers, but may affect these levels in patients with allergic rhinitis.