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Lung function in relation to silicosis and silica exposure in granite workers.

Lung function tests (forced expiratory volume in one second (FEV1), forced vital capacity (FVC) and FEV1/FVC %) were related to silica exposure and the extent of radiological opacities in a study of 206 active and 132 previously employed granite workers from two quarries. The investigations included detailed personal interviews, spirometric testing and radiographic examination of the chest. The chest X-ray films were read randomly and independently by three readers, using International Labour Office (ILO) standard films. Cumulative exposure to respirable silica (mg.m-3-yr) and total granite dust (million particles per cubic foot (mppcf-yr)) were estimated for each subject based on his years of employment at various jobs and historical and current measurements of quarry-, period- and job-specific exposures. The results suggest that chronic simple silicosis, especially for profusion category 2 and 3, was associated with significant lung function loss. As expected, mixed dust fibrosis was associated with little or no functional disturbance. Massive fibrosis was associated with significant obstructive and restrictive impairment. No additional effect of exposure to respirable silica on lung function loss was found after allowing for the presence of "silicosis". However, exposure to total dust (mppcf-yr) appeared to be associated with some lung function loss independent of silicosis. Our results indicate that chronic simple silicosis is not a benign disease; silica exposure is the primary cause, but the lung function loss in silicotics is directly attributable to the fibrotic lung disease. However, exposure to total granite dust beyond the respirable size range may separately produce additional lung function loss.

Adult

[Lung function changes during pregnancy].

The lung functions in different pregnant stages were measured in 41 women with pregnancy and 12 normal women without pregnant. Forced Vital Capacity (FVC) was found gradually decreasing as pregnancy advanced (P less than 0.05). After 28 weeks of gestation, the Vital Capacity (VC), Forced Expired Volume in 1 second (FEV 1) significantly decreased as compared with the normal values (P less than 0.01 or P less than 0.05). These results suggested that the lung function changed gradually during pregnancy, especially after the 28th week, significantly in VC, FVC and FEV 1. Maybe there are slight obstructions in the bronchial tubes. After the 28th week of gestation and it may be the reason for occurrence of breathshort and the lung infection.

Adult

Optimal combinations of lung function tests in the detection of various types of early lung disease.

The ability to detect early lung disease with different combinations of lung function tests was assessed by discriminant analysis. A number of lung function tests were performed in 224 never-smokers, 232 smokers, 111 pneumoconiotic subjects and 137 asthmatic patients. The discriminatory capacities of different combinations of test variables are presented. For detecting lung damage induced by tobacco smoke, a combination of the transfer factor and the slope of the alveolar plateau (phase III) increased the sensitivity from 18% to 32% at a specificity of 95%, compared with phase III alone. Dynamic spirometry did not add to the discriminatory capacity. Patients with asthma could be separated from reference subjects by airway resistance, Phase III or a combination of variables in dynamic spirometry. Pneumoconiotic subjects were best identified by a combination of the transfer factor, volumic compliance and phase III. Closing capacity divided by total lung capacity (TLC) and FEV1/TLC further improved the discrimination between different subgroups.

Airway Resistance

Lung function in atrial septal defect after heart surgery.

Lung volume, indices of lung elasticity and airway patency were measured in 74 patients, 9-21 yr old (15.0 +/- 2.5 yr) with atrial septal defect (secundum type) from 2-11 (5.1 +/- 2.5) yr after successful surgical correction. Clinical condition in all patients was classified as excellent. Heart surgery was performed at the age of 4-14.8 (9.9 +/- 3.0) yr. Lung function abnormalities were found in 35 (47.3%) patients. Lung recoil pressure was significantly increased in 24 (32.4%) patients. The mean value of lung recoil pressure at 100% of total lung capacity reached 123 +/- 31% of the predicted value (P < 0.0001). Specific static compliance was within normal limits. Specific airway conductance was significantly reduced in 13 (17.6%) patients. Maximum expiratory flow at 25% of vital capacity was significantly reduced in 4 (5.4%) patients. Static lung volumes did not differ from reference values. Since various abnormalities of lung function tests (most frequently the tests suggested increased lung stiffness and obstruction of larger airways) were revealed in almost half of the studied children and adolescents after successful surgery for atrial septal defect, we propose to carry out lung function tests routinely as another criterion of health conditions in these patients.

Adolescent

Lung function in essential mixed cryoglobulinemia: a short-term follow-up.

Lung involvement in essential mixed cryoglobulinemia (EMC) has been recently described. In order to assess whether patients with EMC experience an accelerated deterioration of lung function, nineteen patients (17 females, 2 males; 49.6 +/- 6.6 years) underwent a short-term follow-up of lung function, chest X-ray and serologic investigations. Reduction of forced expiratory flows and presence of roentgenologic signs of interstitial involvement were confirmed in the baseline evaluation. In addition, a decrease of diffusing capacity was shown. After a mean interval of 15 months, no significant change in lung function was found, with the exception of decrease in maximal expiratory flow at 50% of forced vital capacity, total lung capacity, functional residual capacity, coefficient of transfer of CO. A slight decrease of hemolitic complement (CH50) and of complement fraction (C3) was also observed. This study suggests that patients with EMC tend to have an involvement of pulmonary interstitial space, possibly related to immune complex deposition, but they do not show a severe decline of lung function. Periodical assessment of lung function and chest X-ray is, however, worthwhile.

Adult

A multinational Andean genetic and health program. VIII. Lung function changes with migration between altitudes.

Studies of lung function in high altitude populations have suggested the influence of hypoxic environment on the development of this characteristic independent of confounding variables such as ethnicity and habitual exercise. However, often the effect of altitude on vital capacity is greater in children than adults, suggesting that more than developmental adaptation is operative. Also selective migration could account for the similarity of migrants and permanent residents at a destination altitude. To explore these problems we studied the lung function (FVC, FEV1, PFR) of 377 individuals who had migrated between altitudes in northern Chile. Migrant measurements were adjusted to those of permanent residents of appropriate age, sex and height at the altitudes of origin and destination. The measurements were then related to ethnicity (Spanish-Aymara ancestry), occupation and permanence, the latter combining information on both age at migration to and length of stay at a destination altitude. Upward migration was associated with increased chest depth, FVC and FEV1, but not height or other chest measurements. Downward migration had no significant effect. The flow-dependent test PFR was so sensitive to observer variability and occupation that it was difficult to establish its relationship to permanence. Unlike the body measurements, lung function measurements (especially PFR) tended to deviate from permanent controls at the origin altitude in a direction suggestive of selective migration, nor was permanence itself independent of ethnicity and occupation. Because of these difficulties the question of developmental adaptation in lung function may not be answerable in cross-sectional studies like the present and previous efforts, but rather in longitudinal investigations in which the control is the individual him/herself.

Adaptation, Physiological

Quantitative lung scintigrams and lung function in the selection of patients for pneumonectomy.

A method for predicting postoperative respiratory function following lung resection has been used in 11 patients with both histologically proven bronchial carcinoma and chronic obstructive airways disease, in order to assess their fitness for surgical treatment. Quantitative ventilation and perfusion scintigrams were used to measure the amount of functioning tissue in each lung. These data were used in conjunction with spirometric measurements to calculate the likely functional effect of pneumonectomy. There was a high degree of correlation (r) between predicted and measured lung function for both FEV1 (r = 0.75, P less than 0.01) and FVC (r = 0.88, P less than 0.01). The postoperative FEV1 was within 150 ml of the predicted value in 45% of the patients. In the remaining patients the actual volumes were greater than predicted by 210-540 ml. For FVC the results were within 150 ml of predicted in 45% of patients and in the remainder actual volumes were greater by 160-650 ml. Both sets of calculations underestimated lung volumes by an average of 200 ml. The method is shown to be accurate, simple, non-invasive, and readily available and brings a degree of objectivity to an important decision that is often based mainly on clinical assessment.

Aged

Lung function after acute bronchiolitis.

We performed 211 lung function measurements on 93 children in the first year after they had been admitted with acute bronchiolitis. During the convalescent phase of the illness, 77% of the infants were hyperinflated with a thoracic gas volume greater than 40 ml/kg and 3 months later 43% were hyperinflated. Twelve months after the initial illness, 17% still had lung function abnormalities and most of these children have had lower respiratory tract symptoms. For the group as a whole about 60% have had at least one episode of wheezing. Specific conductances were significantly lower in children from atopic families, indicating worse lung function, but the significance of this finding is unclear.

Acute Disease

Environmental exposure to tobacco smoke and lung function in young adults.

The relationship between lung function and environmental exposure to tobacco smoke (passive smoking) was studied in 293 nonsmoking young men and women, 15 to 35 yr of age. A self-administered mailed questionnaire was used to assess the lifetime environmental exposure to cigarette smoke at home and at work for each subject. Lung function information used here had been gathered in the course of a previous study of the determinants of lung function in early adulthood. In men, maximal midexpiratory flow rate (FEF25-75) decreased in relation to an index of cumulative lifetime environmental exposure to tobacco smoke at home, after taking into account the effects of cumulative exposure at work as well as age, height, body size, respiratory pressures, and cooking fuels used at home. The components of this exposure index most closely related to the reduction in FEF25-75 were maternal smoking habits and exposure to second-hand smoke during childhood. In women, the diffusing capacity of the lung (DLCO) decreased in relation to cumulative exposure to tobacco smoke at work, after accounting for the effects of cumulative lifetime exposure at home and the other factors mentioned above. These findings contribute to the gathering evidence that environmental exposure to tobacco smoke is harmful to respiratory health, and suggest that the effects are not insignificant. For instance, the FEF25-75 of a young man 20 yr of age who had never smoked and always lived at home would be 800 ml less if both his parents smoked than if they did not.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent

Relationship of lung function loss to level of initial function: correcting for measurement error using the reliability coefficient.

The regression of lung function change on the initial lung function level is biased when the initial level is measured with random error. Several methods have been proposed to obtain unbiased estimates of regression coefficients in such circumstances. We apply these methods to examine the relationship between lung function loss over 11 years and its initial level in 433 men aged about 20 when first seen. On theoretical and practical grounds the best method is the correction of the regression coefficient using the reliability coefficient. This is defined as the ratio of the error free variance to the variance of the variable measured with error, and is easily estimated as the correlation between repeat measurements of the underlying level. In young men the loss of some lung functions (forced vital capacity [FVC], forced expiratory volume in one second [FEV1], forced expiratory flow in the middle half of expiration, and the ratio FEV1/FVC) do not appear to be related to initial level.

Adult

New lung functions and pregnancy.

Newer lung function tests (e.g., flow volume-loops and closing volume), as well as standard pulmonary function tests, were performed on 19 healthy individuals in the third trimester and after delivery. We found that the flow characteristics, manifested in the FVL, and the CV remained unaltered during pregnancy. In regard to the standard pulmonary function tests, we found no statistically significant change except for a decrease in the ERV and in the FRC during pregnancy.

Adolescent

Overnight theophylline concentrations and effects on sleep and lung function in chronic obstructive pulmonary disease.

Circadian alterations in lung function occur in respiratory disorders, with the nadir during the sleep-related hours. Higher therapeutic serum theophylline concentrations (STC) during the night have been shown to improve lung function in reversible airway disease. To determine what effect higher nocturnal STC would have in patients with chronic obstructive pulmonary disease (COPD) on overnight lung function, oxygen saturation, and sleep quality, two different theophylline products were used to give higher or lower STC during the night. We found that with a higher STC (15.0 +/- 1.0 versus 11.0 +/- 1.0 micrograms/ml, p = 0.005) at 7:00 A.M., the overnight changes in FEV1 (+7.4 +/- 5.7% versus -18.9 +/- 7.9%, respectively) and FVC (+1.8 +/- 7.5% versus -17.2 +/- 3.9%, respectively) were significantly better. However, there was no apparent effect on oxygen saturation (mean sleep values for higher STC were 85.3 +/- 1.2%, and for lower STC they were 86.5 +/- 0.8%). The higher STC did not adversely affect sleep latency, sleep efficiency, or sleep staging. We conclude that a higher therapeutic STC during sleep will improve lung function without altering oxygen saturation in patients with COPD. In this group of patients, the higher STC did not interfere with sleep characteristics.

Administration, Oral

Chest physiotherapy in hospitalized patients with cystic fibrosis: a study of lung function effects and sputum production.

In order to evaluate the short-term lung function effects of high-pressure positive expiratory pressure (PEP)-mask physiotherapy (PT) in relation to PT-assisted sputum production, we studied 18 patients with cystic fibrosis (CF), hospitalized for a pulmonary exacerbation. Lung functions were measured before (a) and after PT (b) on day one (1), five (2), ten (3) and fifteen (4). Five functions improved significantly from a1 to b1, eight from a2 to b2, seven from a3 to b3, and seven from a4 to b4. Baseline (a) measurements improved only slightly, but post-PT (b) values improved more markedly from 1 to 4, and this improvement reached statistical significance for six functions; consequently, a-to-b lung function changes tended to increase from investigation 1 to 4. Eleven PT-induced lung function changes correlated to the weight of sputum produced. High-pressure PEP-mask PT therefore resulted in significant lung function improvements, and not only maintained but increased its effect in the course of the hospitalization.

Adolescent

Bird breeder's hypersensitivity pneumonitis: progress studies of lung function after cessation of exposure to the provoking antigen.

Lung function and immunologic studies have been performed in 9 patients with bird breeder's hypersensitivity pneumonitis at the time of diagnosis and at intervals from 8 to 30 months after they ceased exposure to the provoking antigen. All 9 patients had evidence of small airway obstruction at the time of diagnosis. Complete recovery of lung function occurred in 4 patients. The other 5 all had evidence of interstitial damage; 3 of them had progressive increase in the degree of airway obstruction, and one had progressive loss of elastic recoil. The patients were nonsmokers, and these progressive changes could not be explained by occult exposure to antigen because the tests of immunologic sensitivity to relevant avian antigens became negative. Neither the nature or degree of lung function abnormality nor the form of clinical presentation was related to the development of residual damage. The period of exposure to antigen after symptoms developed and the age of the patient appeared to be the most important factors determining recovery of lung function.

Adolescent

Lung function in children with recurrent bronchitis.

Lung function was studied in 29 children suffering from recurrent bronchitis (average number of bronchitis attacks per year: 4.2 +/- 0.5). Most of them (73%) were 1--7 years old. The date of exploration in relation to the last acute bronchitis was on average 6 weeks. Lung mechanics, residual functional capacity, blood gases and regional lung function were measured. Most of the children were suffering from some kind of functional disorder; alteration of lung mechanics -- increase of lung resistance (22/29) decrease of dynamic compliance (15/23); increase of functional residual capacity (6/10), non specific bronchial hypersensitivity (12/17); regional ventilatory and perfusion malfunction. These functional disorders could be the first evidence of the bronchial lesions which cause chronic obstructive bronchitis in adults.

Bronchitis

Study of lung function data by principal components analysis.

As a rational approach to the many lung function tests available, we have subjected the results of a battery of six lung function measurements made in 458 coalminers to the statistical technique of principal components analysis. By this means the six test results were reduced to three principal components without important loss of information. The first component appeared to represent lung size and the second the degree of airflow obstruction, and the third detected impairment of gas transfer factor in excess of that explained by the first two components. The values of the first principal component, used to select men with abnormal lung function, identified more younger men with functional abnormalities than a method based on comparison of observed and predicted values of forced expiration volume in one second. The values of the second and third principal components were used to classify types of functional abnormality. It is concluded that this statistical technique provides a sensitive method of identifying men with unusual lung function, particularly younger men, in a population and can be used to define and quantify different aspects of lung function.

Adult

The UCLA population studies of chronic obstructive respiratory disease. VII. Relationship between parental smoking and children's lung function.

Results of previous studies of the impact of parents' smoking on children's lung function have been conflicting. To evaluate further the effect of passive smoking on the lung function of children, we analyzed respiratory questionnaire and lung function results obtained during field testing of residents (aggregated according to household) of 4 census tracts in the Los Angeles area. We report here on 971 white, non-Hispanic, nonsmoking, nonasthmatic children residing in households in which the smoking status of both parents was known; households with ex-smoking parents were excluded from analysis. We divided these children into 3 categories related to parental smoking status: (1) at least mother smokes , (2) only father smokes , and (3) neither parent smokes . Prediction equations for several indexes of forced expired volume and flow were derived separately for boys and girls 7 to 17 yr of age. Analysis of variance was used to compare lung function residuals of children in the 3 different passive smoking categories. Analysis was performed separately on younger (7 to 11 yr of age) and older (12 to 17 yr of age) children of each sex. Among younger male children, residual values were significantly lower in the maternal smoking category than in the other 2 household categories for maximal flow and maximal flow after exhalation of 25% of forced vital capacity (FVC) (p less than or equal to 0.05); no differences were noted between the paternal-smoking only and nonsmoking household categories. A trend toward similar results was found in older male children, which approached significance (p less than 0.1). Among females, forced expiratory flow during the middle half of the FVC and maximal flow after exhalation of 75% of FVC were significantly lower in relation to maternal smoking in the older children only (p less than or equal to 0.05). ANOVA revealed no decrement in lung function in relation to passive smoking among children with asthma or bronchitis (n=138).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent