139 BOS, “DeBos” and “ReBos”: When Is a Drop in the FEV1 Really Permanent?
M. FregosoR BrennerJacob CollenTaylor ReffettAnne BrownOksana A. ShlobinS AhmadMerte LemmaSteven D. Nathan
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Keywords:
Vital capacity
Plethysmograph
Vital capacity
Respiratory physiology
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Lung size was evaluated with pulmonary function tests in 10 patients with acromegaly, 1 pituitary giant, and 1 patient who had acromegaly but now has hypopituitarism. In the six acromegalic men all lung volumes were increased. The average values and per cent of predicted were total lung capacity 9.1 liters. 139%; functional residual capacity 5.2 liters, 145%; vital capacity 6.0 liters, 134%; and tissue volume 1.1 liters. There was no evidence of airflow obstruction or air trapping. Anatomic dead space was increased in proportion to the large lung volumes. Lung compliance was increased, averaging 0.43 liters/cm H(2)O, but lung elastic recoil was normal. These studies show that the lung is involved in the general visceromegaly of acromegaly and that lung size increases in acromegalic men as a result of actual lung growth. Despite the large lung volumes, diffusing capacity was normal suggesting that lung growth resulted from an increase in the size rather than from an increase in the number of alveoli. In contrast to the acromegalic men, lung volumes, anatomic dead space and tissue volume were normal in four acromegalic women, suggesting that sex hormones may modify the effect of growth hormone on the lung. Lung size was large in the pituitary giant but lung volumes were normal according to predicted values based on the patient's great height. Lung volumes were normal in the one male who had been acromegalic but who has been hypopituitary for 21 yr. The role of growth hormone in normal postnatal lung growth and in the maintainance of normal lung size remains to be defined.
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Introduction: Dynamic chest radiography (DCR) is a novel technology that allows real time observation of respiratory kinetics and measurement of lung volumes during the respiratory cycle. Aim: To correlate measurements of lung area during deep inspiration on posteroanterior (PA) and lateral DCR images and derived lung volume with Total Lung Capacity (TLC) measured using whole body plethysmography. Methods: DCR images from 15 healthy volunteers obtained during deep breathing were analysed. A standardised protocol was used to measure maximal PA right lung apex-diaphragm distance, total PA lung area and lateral lung area during maximum inspiration. These values were used to derive lung volumes as previously described (1). The results were correlated with volunteers' TLC. Pearson correlation coefficients were applied to determine correlations. Results: DCR measured PA lung area and calculated lung volume during maximal inspiration correlated significantly with TLC (r=1, p<0.001; r=0.9, p<0.001 respectively). The maximum apex -diaphragm right lung distance correlated with right lung area (r=0.9, p<0.001). Conclusion: DCR measurements during deep breathing correlates with TLC measured using conventional method. DCR offers the prospect of measuring lung function with minimal patient effort. Larger studies are required. Reference: 1. A Method for the Determination of Total Lung Capacity from Posteroanterior and Lateral Chest Roentgenograms.' American Review of Respiratory Disease, 96(3), pp. 548–552
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Electron beam X-ray computed tomography (CT) was used to measure lung air content and its distribution within the lung as well as lung shape and heart position in rabbits in right and left lateral recumbency. Sham-operated control (S) rabbits and left-pneumonectomized rabbits with wax plombage were studied at functional residual capacity (FRC) and total lung capacity. Results were obtained for both lungs and for the right lung only of S rabbits. FRC of both lungs and the right lung only of the S rabbits and of the remaining right lung of the pneumonectomized rabbits was smaller in rabbits in right lateral recumbency than in those in left lateral recumbency. The reduction in right lung volume at FRC was accompanied by an overall reduction in lung size, although the lung shape remained similar, and was accompanied by movement of the heart centroid toward the dependent chest and spine. Application of a positive tracheal pressure of 25 cmH2O increased lung volume and reduced the dependency of lung volume and shape on posture. Lung inflation in the right lateral position was accompanied by movement of the heart centroid away from the dependent chest and spine. Gravitational gradients in regional air content did not differ between the cranial half of the lung, which was in contact with the heart, and the caudal half of the right lung, which was not in contact with the heart. Likewise, the cephalocaudal gradient in regional air content was similar when the right lung was dependent and nondependent. The location of the heart in the cranial half of the thorax does not appear to induce differences in regional air content between the cranial and caudal lung halves.
Left lung
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The relationship between lung function and smoking and dietary habits was examined in 121 Gypsies (62 males, 59 females) who were 14-70 y of age and who lived in Greece. All were examined clinically, after which they all participated in spirometry tests. Half of the study group had abnormal (< 80% of predicted) forced vital capacity, 36.4% had abnormal (< 80% of predicted) forced expiratory volume in 1 sec, and 5% had serious lung function disturbances (forced vital capacity < 50% of predicted). Approximately 70% of subjects were smokers, and their diets were rich in alcohol and meat; they ate very few salads and oranges. Consequently, decreased lung function might be a major health problem in Gypsies in Greece. Organization of preventive health strategies should improve the overall health of this study group.
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Objective To observe the effects of scoliosis on pulmonary function.Methods 31 cases of scoliosis were included and underwent pulmonary function test(PFT).The cases were divided into an adolescent group(16 cases) and an adult group(15 cases) according to age.Predicted value was used as a reference to assess various PFT parameters.Results In both groups,forced expiratory volume in one second,forced vital capacity,and pulmonary diffusion decreased.In the adolescent group,residual volume,functional residual volume,and total lung capacity decreased.In the adult group,vital capacity and maximal voluntary ventilation decreased,the ratio of forced expiratory volume in one second to forced vital capacity decreased,and resonance frequencies increased significantly compared with the adolescent group(P0.05).Conclusion Scoliosis may lead to restrictive ventilation defect,which is mainly lung volume reduction in adolescent patients and more severe in adult patients.
Vital capacity
Residual volume
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We measured transdiaphragmatic pressure (Pdi) during forced expiratory vital capacity (FVC) maneuvers in 13 normal subjects and electromyographic activity of the diaphragm (edi) in 8 of these subjects. In all subjects, Pdi increased at the initiation of the FVC. In most, this increase lasted 30--50 ms and reached levels well above the Pdi observed at total lung capacity (TLC). After the initial transient increase, approximately half of the subjects demonstrated a substantial fall in Pdi to values near the relaxation level in the mid-vital capacity (VC) volume range, while half showed a second large increase in Pdi in this volume range. Seven of eight subjects tested showed a rapid decrease in Edi at the onset of the FVC, reaching a minimum in 30--50 ms. After this initial transient decrease, Edi increased in six subjects in the mid-VC volume range, in association with secondary rises in Pdi. In two subjects, Edi remained low throughout the remainder of the FVC, and Pdi in the mid VC range was generally lower. These results are consistent with the conclusion that the diaphragm is neither electromyographically silent nor mechanically unimportant during the FVC. Changes in abdominothoracic configuration, superimposed upon “antagonistic” activity of the diaphragm, result in substantial reductions in pleural (esophageal) pressure that may influence regional lung emptying during the FVC.
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Diaphragm (acoustics)
Diaphragm muscle
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Tables are presented showing estimates of the number of subjects which is required to give an 80% or 90% chance of detecting various differences in forced expiratory volume in one second, forced vital capacity, total lung capacity, transfer factor, and residual volume between the mean of two groups by means of Student9s t test.
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Residual volume
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This study was carried out to obtain normal lung function values for women in south eastern Nigeria with a view to establishing prediction equations for forced vital capacity (FVC), forced expiratory volume at the first second (FEV1) and peak expiratory flow rate (PEFR). Lung function values were measured in 600 apparently healthy Nigerian women aged between 18 and 57 years. FVC and FEV1 were significantly related to height (P
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Background: The frequently measured index of pulmonary function is vital capacity which gives useful information about the strength of respiratory muscles and other aspects of lung function. The purpose of the study was to investigate changes that occur in vital capacity in different postural attitudes like standing, supine, right lateral, left lateral positions compared with the reference position such as upright sitting in normal subjects.Methods: Young non-smoker healthy male medical students (n=20, age 19-22 years) of PSG Medical College participated as volunteers in this study. Pulmonary function tests like forced vital capacity (FVC), Forced Expiratory Volume in one second (FEV1), FEV1 to FVC% i.e. (FEV1%) was recorded in various postures using computerized spirometer in BIOPAC systems, Inc., MANBSL3S, student version, following the standard procedure.Results: A repeated measure ANOVA-multiple comparison study revealed FVC, FEV1 and FEV1% values in standing posture was significantly higher than supine, sitting, right and left lateral positions.Conclusions: Naturally, in standing posture factors contributing to increased vital capacity are increased, vertical diameter of thorax which increases thoracic capacity volume and lung compliance increasing lung volume.
Spirometer
Supine position
Vital capacity
Sitting
Body position
Thorax (insect anatomy)
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