Rev Port Pneumol. 2007 Nov-Dec;13(6):763-74.
[The importance of diffusing capacity as a complementary study to plethysmography in smokers]
[Article in Portuguese]
Paes Cardoso A, Reis Ferreira JM, Moreira da Silva A.
Human Physiology, Porto University, Instituto de Ciências Biomédicas de Abel Salazar, Santo António Hospital.
Abstract
This study comprised 194 male and female heavy smokers or ex-smokers (>or= 1 pack-year) aged between 20 and 82, whose symptoms varied. Cases were only selected from patients with normal whole-body plethysmography. Subjects with any significant pathology and occupational risk factors were excluded from the study. Varying degrees of symptoms were found and a range of results from normal plethysmography examination, with abnormal levels of alveolar-capillary transfer, determined by the single-breath method to analyse CO (TLCO and TLCO-VA) coefficients. Using the chi-square test for statistical analysis of the sample revealed a significant variation in sensitivity between both parameters (p=0.0001). Possible limitations of using the single-breath method, of were reduced in this study (ventilatory restriction with Vital Capacity <1.5 litres) by the routine plethysmography results seen. Likewise, the presence of alterations in ventilatory distribution was, in principle, minimised by the absence of TLCsb/TLCplet values below 0.85% CONCLUSIONS: Normal plethysmography results in heavy or ex-smokers are not enough to confirm normal respiratory function, as a large percentage of cases present abnormalities in the alveolar-capillary transfer factor for CO. Alveolar limitation was considered not only anatomically, but also from a functional perspective.
PMID: 18183328 [PubMed - indexed for MEDLINE
