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 ...

Alveolar and lung liquid clearances were studied over 1, 4, and 6 h in intact anesthetized ventilated rats by instillation of 5% albumin solution with 1.5 microCi of 125I-labeled albumin (3 ml/kg into 1 lung or 6 ml/kg into both lungs). Alveolar protein clearance as measured by residual 125I-albumin in the lung over 6 h was similar to the slow rates measured in other species. Alveolar liquid clearance was estimated by the concentration of albumin in the air spaces. After 1 h, this concentration was 7.8 +/- 0.7 g/dl, which was significantly greater than the initial protein concentration of 5.3 +/- 0.2 g/dl (P < 0.05). Amiloride (10(-3) M) inhibited 45% of the basal alveolar liquid clearance, and ouabain (10(-3) M), instilled and intravenously infused (0.004 mg), inhibited 30% of the clearance. beta-Adrenergic agonist instillation increased alveolar liquid clearance to the fastest 1-h rate (48 +/- 3% of instilled volume) that we observed in any intact species. The removal of the instilled fluid from the lung (expressed as lung liquid clearance; 0.96 +/- 0.3 ml/h) was twice as fast as the rate of alveolar and lung liquid clearance reported in the isolated or in situ rat lung models. The rate of alveolar and lung liquid clearance in these intact rats was significantly faster than those in prior studies in dogs and sheep and was similar to the rates in rabbits.

The objective of the present study was to establish multiethnic, all-age prediction equations for estimating stature from arm span in males and females.The arm span/height ratio (ASHR) from 13 947 subjects (40.9% females), aged 5-99 years, from nine centres (in China, Europe, Ghana, India and Iran) was used to predict ASHR as a function of age using the lambda, mu and sigma method. Z-scores for forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC) and FEV1/FVC in 1503 patients were calculated using measured height and height calculated from arm span and age.ASHR varied nonlinearly with age, was higher in males than in females and differed significantly between the nine sites. The data clustered into four groups: Asia, Europe, Ghana and Iran. Average predicted FEV1, FVC and FEV1/FVC using measured or predicted height did not differ, with standard deviations of 4.6% for FEV1, 5.0% for FVC and 0.3% for FEV1/FVC. The percentages of disparate findings for a low FEV1, FVC and FEV1/FVC in patients, calculated using measured or predicted height, were 4.2%, 3.2% and 0.4%, respectively; for a restrictive pattern, there were 1.0% disparate findings.Group-and sex-specific equations for estimating height from arm span and age to derive predicted values for spirometry are clinically useful. @ERSpublications Height estimated from arm span, age and ethnic group allows clinically valid classification of spirometric data

Magnetic resonance (MR) imaging of the thorax with three-dimensional (3D) reconstruction and functional quantification was evaluated as a tool for structure-function evaluation of chest-wall mechanics. Good agreement was found between the corresponding spirometric and MR imaging values of lung volumes. Fast MR imaging of the thorax with 3D reconstruction should improve the ability to evaluate the inspiratory pump in clinical and research investigations.