[The importance of lung volumes in the investigation of heavy smokers].
BACKGROUND
Lung hyperinflation (LH) has become a major concern in the management of chronic obstructive pulmonary disease (COPD).


OBJECTIVE
To evaluate the role of lung volumes in the positive diagnosis of COPD and in the assessment of airway obstruction reversibility.


METHODS
Three hundred and sixty-six male smokers over the age of 35 with more than 40 pack-years exposure were included in the study. Plethysmographic data were determined before/after taking a bronchodilator (BBD, ABD). Applied definitions: airflow obstruction: BBD FEV1/FVC<0.70. LH: BBD residual volume (RV)>upper limit of normal. Expressions of reversibility: Δvariable=(ABD-BBD) values; Δinit%=Δvariable/BBD value and Δref%=Δvariable/reference value. A 12%init and a 0.2L increase in either FEV1 or FVC or a 10%ref or - 300 mL decrease in RV were considered as clinically significant.


RESULTS
Over the 85 smokers without airflow obstruction, 68% had LH. In the hyperinflated group (n=314), and compared to changes in FEV1 and FVC, these RV changes detected more respondents (54% for FEV1 and FVC vs. 65% for RV, P=0.002). This was not the case for the group free from LH (n=52) (23% for FEV1 and FVC vs. 35% for RV, P=0.09). In the 58 hyperinflated groups free from airflow obstruction, and compared to changes in FEV1 and FVC, changes in RV detected more respondents (24% for FEV1 and FVC vs. 71% for RV, P=0.0001).


CONCLUSIONS
In heavy smokers, it seems essential to include LH as a criterion for a positive diagnosis of COPD and of reversibility evaluation.
Service de physiologie et des explorations fonctionnelles, EPS Farhat Hached, Sousse, Tunisie; Laboratoire de physiologie, faculté de médecine « Ibn Eljazzar » de Sousse, université de Sousse, avenue Mohamed Karoui, 4000 Sousse, Tunisie. Electronic address: helmi.bensaad@rns.tn.
H
H
Ben Saad
Service de physiologie et des explorations fonctionnelles, EPS Farhat Hached, Sousse, Tunisie.
L
L
Ben Amor
Service de physiologie et des explorations fonctionnelles, EPS Farhat Hached, Sousse, Tunisie.
S
S
Ben Mdalla
Service de physiologie et des explorations fonctionnelles, EPS Farhat Hached, Sousse, Tunisie; Laboratoire de physiologie, faculté de médecine « Ibn Eljazzar » de Sousse, université de Sousse, avenue Mohamed Karoui, 4000 Sousse, Tunisie.
I
I
Ghannouchi
Service de physiologie et des explorations fonctionnelles, EPS Farhat Hached, Sousse, Tunisie.
M
M
Ben Essghair
Consultation externe de pneumologie, groupement de santé de base, Sousse, Tunisie.
R
R
Sfaxi
Service de pneumologie, EPS Farhat Hached, Sousse, Tunisie.
A
A
Garrouche
Service de pneumologie, EPS Fattouma Bourguiba, Monastir, Tunisie.
N
N
Rouatbi
Service de physiologie et des explorations fonctionnelles, EPS Farhat Hached, Sousse, Tunisie; Laboratoire de physiologie, faculté de médecine « Ibn Eljazzar » de Sousse, université de Sousse, avenue Mohamed Karoui, 4000 Sousse, Tunisie.
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S
Rouatbi
D000328:Adult; D000368:Aged; D006801:Humans; D008137:Longitudinal Studies; D008168:Lung / Q000473:pathology* / Q000503:physiopathology; D008176:Lung Volume Measurements; D008297:Male; D008875:Middle Aged; D009929:Organ Size; D011237:Predictive Value of Tests; D029424:Pulmonary Disease, Chronic Obstructive / Q000175:diagnosis* / Q000473:pathology / Q000503:physiopathology; D012720:Severity of Illness Index; D012907:Smoking / Q000009:adverse effects / Q000473:pathology* / Q000503:physiopathology; D014029:Tobacco Use Disorder / Q000150:complications / Q000175:diagnosis / Q000473:pathology* / Q000503:physiopathology
BPCO; COPD; Diagnosis; Diagnostic; Distension pulmonaire; Hyperinflation; Plethysmography; Pléthysmographie; Reversibility; Réversibilité