Effect of Airway Opening on Production of Exhaled Particles.

• The technique of sampling exhaled air is attractive because it is non-invasive, and so allows repeated sampling with ease and no risk for the patient. Knowledge of the biomarkers' origin is important in order to correctly understand and interpret the data. Endogenous particles, formed in the airways, are exhaled and reflect chemical composition of the respiratory tract lining fluid. However, the formation mechanisms and formation sites of these particles are unknown. We hypothesize that airway opening following airway closure cause production of airborne particles that are exhaled. The objective of this study was to examine production of exhaled particles following varying degrees of airway closure. 10 healthy volunteers performed 3 different breathing manoeuvres in which the initial lung volume preceding an inspiration to total lung capacity was varied between functional residual capacity (FRC) and residual volume (RV). Exhaled particle number concentrations in the size interval 0.30-2.0 mum were recorded. Number concentrations of exhaled particles showed a 2-18 fold increase after exhalations to RV compared to exhalations where no airway closure was shown (8500 (810-28000) vs. 1300 (330-13000) particles/expired litre, p=0.012). The difference was most noticeable for the smaller size range of particles (<1 mum). There were significant correlations between particle concentrations for the different manoeuvres. Our results show that airway reopening following airway closure is an important mechanism for formation of endogenous exhaled particles and that these particles originate from the terminal bronchioles. Key words: exhaled particles, airway closure, breath.

Ämnesord

MEDICIN OCH HÄLSOVETENSKAP  -- Medicinska och farmaceutiska grundvetenskaper -- Fysiologi (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Basic Medicine -- Physiology (hsv//eng)

Nyckelord

airway closure

breath

Publikations- och innehållstyp

ref (ämneskategori)

art (ämneskategori)