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This Article Full Text Full Text (PDF) All Versions of this Article: 28/2/323    most recent 09031936.06.00122505v1 Alert me when this article is cited Alert me if a correction is posted Permissions Request Permissions Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Web of Science (1) Citing Articles via Google Scholar Google Scholar Articles by Fregonese, L. Articles by Stolk, J. Search for Related Content PubMed PubMed Citation Articles by Fregonese, L. Articles by Stolk, J.

Ventilation inhomogeneity in ₁-antitrypsin-deficient emphysema

Lung Function Laboratory, Dept of Pulmonology, Leiden University Medical Centre, Leiden, The Netherlands.

CORRESPONDENCE: L. Fregonese, Dept of Pulmonology (C3-P), Leiden University Medical Centre, P.O. Box 9600, 2300 RC Leiden, The Netherlands. Fax: 31 715266927. E-mail: l.fregonese{at}lumc.nl

Keywords: ₁-Antitrypsin deficiency, cigarette smoking, diffusion capacity, emphysema, single-breath nitrogen wash-out test, small airways

Received: October 19, 2005
Accepted March 12, 2006

The slope of phase III of the single-breath nitrogen wash-out test (sbN₂-test) measures ventilation inhomogeneity and, in smokers, is strongly associated with small airways pathology. The present authors aimed to study ventilation inhomogeneity in emphysema related to type Z ₁-antitrypsin (AAT) and to assess its relationship with indices of parenchymal damage and airways obstruction.

A total of 18 subjects, consisting of ex-smokers with type Z AAT and emphysema (confirmed by computed tomography scan), were studied in a cross-sectional design. Post-bronchodilation flow–volume curves and gas transfer parameters were measured; sbN₂-test curves were obtained and the slope of phase III was determined.

The mean value of the slope (4.6±1.3% N₂·L^-1) was higher than reference values +2SD; it was significantly correlated with the transfer factor of the lung for carbon monoxide (R = -0.75) and the transfer coefficient of the lung for carbon monoxide (R = –0.58), but not with airways obstruction. There was no correlation between phase III slope values and cumulative smoking.

In patients with type Z ₁-antitrypsin emphysema, the increased ventilation inhomogeneity predominantly reflects parenchymal abnormalities, demonstrating that measurement of airways obstruction is not sufficient to characterise the disease. Determination of the sensitivity of the single-breath nitrogen wash-out test slope in detecting disease progression may give complementary information to spirometry.