The landmark study of Fletcher and Peto on the natural history of tobacco smoke-related chronic airflow obstruction suggested that decline in the forced expiratory volume in the first second (FEV1) in chronic obstructive pulmonary disease (COPD) is slow at the beginning, becoming faster with more advanced disease. The present authors reviewed spirometric data of COPD patients included in the placebo arms of recent clinical trials to assess the lung function decline of each stage, defined according to the severity of airflow obstruction as proposed by the Global Initiative for Chronic Obstructive Lung Disease (GOLD) guidelines. In large COPD populations the mean rate of FEV1 decline in GOLD stages II and III is between 47 and 79 mL/year and 56 and 59 mL/year, respectively, and lower than 35 mL/year in GOLD stage IV. Few data on FEV1 decline are available for GOLD stage I. Hence, the loss of lung function, assessed as expiratory airflow reduction, seems more accelerated and therefore more relevant in the initial phases of COPD. To have an impact on the natural history of COPD, it is logical to look at the effects of treatment in the earlier stages.

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Bronchodilating agents are commonly used in patients with chronic obstructive pulmonary disease (COPD) to reduce airway obstruction [1]. Although many COPD patients may obtain substantial increase in airflow after inhalation of bronchodilators [2], one-third of them do not show significant acute spirometric changes [3]. It is a common tenet, however, that improvements in symptoms and exercise capacity may occur even in the absence of spirometric improvement [4]. Such findings are frequent in patients with relatively severe COPD (forced expiratory volume in one second (FEV1) <50% pred), who often exhibit expiratory flow limitation (EFL) during resting breathing, i.e. their tidal expiratory flow is maximal under the prevailing condition [5].In the presence of EFL, the expiratory flow can increase only by breathing at higher lung volume. Thus, EFL promotes dynamic pulmonary hyperinflation, a condition where the end-expiratory lung volume (EELV) is greater than the relaxation or elastic equilibrium volume (Vr). As a result, there is a positive end-expiratory pressure (PEEP) in the alveoli which is called intrinsic PEEP (PEEPi) and acts as an inspiratory threshold load [6]. Dynamic hyperinflation is associated not only with increased inspiratory work due to PEEPi [7] but also with impaired inspiratory muscle function [8]. This, together with flow-limiting dynamic compression during tidal breathing, may contribute to dyspnoea in flow-limited COPD patients [9,10]. Indeed, in a study by ELTAYARA et al. [9], the severity of chronic dyspnoea was found to correlate much more closely with flow limitation than with usual spirometric indices.The aim of this study was to assess whether, in patients with moderate-to-severe COPD, the administration of a bronchodilator (short-acting β 2 -agonist) abolished EFL and/or reduced the EELV during tidal breathing. EFL was assessed with the negative expiratory pressure (NEP) method [5,11]. Tidal EFL was also assessed with the conventional method based on comparison of tidal with maximal flow-volume (V '-V) curves obtained with body plethysmography [12]. Methods SubjectsEighteen patients (14 males and four females, aged 65±2 yrs (mean±SEM), range 48-77 yrs) suffering from COPD according to the American Thoracic Society (ATS) guidelines [1] were studied when in a stable condition.Effect of salbutamol on dynamic hyperinflation in chronic obstructive pulmonary disease patients. C. Tantucci, A. Duguet, T. Similowski, M. Zelter, J-P. Derenne, J. Milic-Emili. ©ERS Journals Ltd 1998. ABSTRACT: Expiratory flow limitation (EFL), which promotes dynamic hyperinflation and increased work of breathing, often occurs in chronic obstructive pulmonary disease (COPD). The purpose of this study was to assess the effect of bronchodilators on EFL and end-expiratory lung volume in patients with moderate-to-severe COPD.EFL was assessed by applying negative expiratory pressure (NEP) at the mouth during tidal expiration. EFL was present when expiratory flow did not increase or increased only in the early phase ...

Background: Despite the widespread use of fractional exhaled nitric oxide (FE NO ) as a biomarker of airways inflammation, there are no published papers describing normal FE NO values in a large group of healthy adults.

IC (%pred.) is a powerful functional predictor of all-cause and respiratory mortality and of exacerbation-related hospital admissions in COPD patients.