Respiratory functional evaluation and pulmonary hyperinflation in asymptomatic smokers: Preliminary study

Abstract

ObjectivesTo investigate the respiratory function and lung hyperinflation in asymptomatic smokers without previous pulmonary pathology and with normal chest radiography. To identify tobacco-related diseases and to correlate tobacco consumption, duration of exposure to tobacco smoke and urinary cotinine with the existence of tobacco-related disease. Material and methodsCase-controlled study with pairing by sex, age, and body mass index. Case definition: smokers who presented to the first appointment of smoking cessation at the Hospital Sousa Martins (HSM) without respiratory symptoms and with normal chest radiography. Definition of control: users without current and/or past tobacco exposition and with plethysmography and chest radiography at HSM within normal parameters. ResultsReductions in FEV1/FVC, FEF 75%, FEF 25–75% and the cardiothoracic index were detected in smokers and showed a moderated inverse correlation of TLC (with statistical meaning) compared with the control group. Approximately 31.2% of the smokers showed extrapulmonary disease related to tobacco, and 9.38% of the smokers exhibited subclinical chronic obstructive pulmonary disease (COPD). Smokers with tobacco-related diseases presented a mean age and RV/TLC ratio superior to smokers without pathology. DiscussionThe reduction of the mean values of FEV1/FVC, FEF 75%, FEF 25–75% and the cardiothoracic index seems to indicate precocious pulmonary dysfunction. This work aims to reveal the importance of detecting premonitory anomalies of pulmonary disease during the subclinical phase in patients at risk. Smoking must be considered a factor of multisystemic repercussion; thus, intervention opportunities in this particular group must not be wasted. This preliminary study identifies potentially promising variables with the aim of testing the hypothesis that there can be premonitory alterations in COPD, according to its evolution versus reversibility after smoking cessation. This work will be concluded in a future study.