[Which definition to use when defining airflow obstruction?]. / Quelle définition faut-il choisir pour le déficit ventilatoire obstructif?

INTRODUCTION: There is no clear consensus as to what constitutes an obstructive ventilatory defect (OVD). According to the American Thoracic Society and European Respiratory Society, it is defined as being when the ratio of the forced expiratory volume (FEV1) and the slow expiratory vital capacity (VC) is below the lower limit of normal (LLN). According to the Global initiative for chronic Obstructive Lung Disease and the British Thoracic Society, it is an FEV1/forced expiratory vital capacity (FVC)<0.70 and an FEV1<80%. In addition, in daily practice, the OVD is diagnosed by a "Fixed ratio" FEV1/FVC<0.70 or

[Which definition to use when defining reversibility of airway obstruction?]. / Quelle définition faut-il choisir pour la réversibilité de l'obstruction bronchique?

INTRODUCTION: There is no clear consensus about what constitutes reversibility of airway obstruction. European Respiratory Society (ERS): Increase in FEV1 and/or FVC>12% of their theoretical value and>0.2l. British Thoracic Society: FEV1>15% of initial value and FEV1>0.2l. Global Initiative for Chronic Obstructive Lung Disease: Increase in FEV1>12% and>0.2l. Australia and New Zealand Thoracic Society: Increase in FEV1 >15%. American Thoracic Society/ERS: Increase in FEV1>12% and>0.2l or increase in FVC>12% and 0.2l. Our principal objective was to determine the percentage of patients with COPD (n=62) who were significant responders to the reversibility test according to the 5 recommendations. METHODS: Plethysmography was performed before and 15 minutes after inhalation of 400 micrograms of a short acting bronchodilator (BD). COPD is defined as a FEV1/FVC post BD<0.7. RESULTS: The percentage of responders varied from 24% to 50% depending on the recommendations used. CONCLUSION: Reversibility of airway obstruction is recommendation dependent.

[Aging of the lung parenchyma]. / Vieillissement du poumon profond.

INTRODUCTION: The study of lung parenchymal function is focused on the measurement of carbon monoxide diffusing transfer (TLCO) which is a function of both membrane characteristics (Dm) and capillary lung volume (Vc) The objective of this study was to estimate the effect of age on both variables. METHODS: At rest, 134 healthy non-smokers (18-85 year old) were investigated by a double transfer NO-CO method. Capillary pulmonary compliance was estimated by applying a continuous negative pressure (CNP: -10 mmHg) at the mouth to 24 subjects. RESULTS: Significant decreases in VA, TLCO, TLNO, Dm and Vc in relation to age were observed (p < 0.05). CNP induced a significant increase in all variables, the increase in Vc in elderly was greater than that in younger subjects. CONCLUSION: Alveolo capillary membrane aging induces a decrease in Dm and Vc, however the increase in the estimated capillary compliance with CNP could provide an adaptation to the decrease in Vc.