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PubMedDate not supplied

Seasonal changes in lung function in a farming population.

OBJECTIVE: To assess the changes in respiratory health from winter to summer seasons in a rural population. DESIGN: A longitudinal design was used in the study. SETTING: A population-based study was conducted as part of the Environmental Pesticide Exposure and Human Health component of the Prairie Ecosystem Study (PECOS) in southwestern Saskatchewan. PATIENTS: In the winter season, 358 patients participated in the study. Of these patients, 234 returned for the second assessment during the summer season. After excluding 34 children aged 17 years and under, 200 adult patients were available for analysis. MEASUREMENTS: Questionnaires were used to obtain information on demographic factors, smoking habits, occupational and environmental exposures, and respiratory conditions. Pulmonary function measurements were obtained using a volume displacement spirometer. RESULTS: Mean ages (+/- SD) of the 106 men and 94 women participating in the study were 50.1+/-13.3 and 49.0+/-13.1 years, respectively. Mean percentage changes in maximal midexpiratory flow rate from winter to summer assessments indicated an improvement for town residents and a decline for farm residents. Mean percentage changes in the ratio of forced expiratory volume in 1 s to forced vital capacity indicated an improvement for town residents who were not engaged in farming, and increasing declines for town residents engaged in farming, farm residents not engaged in farming and farm residents engaged in farming. CONCLUSIONS: Seasonal changes occurred in measurements of pulmonary function between winter and summer seasons; these changes may be related to the environmental or occupational exposures experienced by the participants during the study.

Agricultural Workers' Diseases↗
PubMedDate not supplied

Spirometric predictors for the exclusion of severe hypoxemia in chronic obstructive pulmonary disease.

BACKGROUND: Controversy has existed over the need for routine arterial blood gas (ABG) analysis in patients with chronic obstructive pulmonary disease (COPD). Some authors recommend it in all patients with COPD, but others find it unnecessary if the forced expiratory volume in 1 s (FEV(1)) is 50% of predicted or greater. OBJECTIVES: To clarify this controversy, and to investigate correlations between severe hypoxemia and multiple spirometric parameters in patients with COPD with FEV(1) 50% of predicted or greater. PATIENTS AND METHODS: In 103 consecutive patients with COPD with FEV(1) 50% of predicted or greater, and without any other cardiopulmonary disorder, the incidence of severe hypoxemia (partial pressure of arterial oxygen less than 60 mmHg) was established by ABG analysis. Positive and negative predictive values (PPVs and NPVs, respectively) for severe hypoxemia for multiple spirometric parameters (FEV(1), FEV(1)/forced vital capacity [FVC], peak expiratory flow [PEF], maximal midexpiratory flow rate [FEF(25-75)]) were evaluated in a stepwise manner. RESULTS: Twenty-two patients (21%) were found to be severely hypoxemic. In the severely hypoxemic group, the mean values for FEV(1), FEV(1)/FVC, PEF and FEF(25-75) were 59.0+/-8.19%, 53.6+/-11.3, 50.6+/-9.3 and 34.4+/-14.2% of predicted, respectively. The mean values for the same parameters in the other patients were 58.0+/-4.6%, 52.7+/-7.8, 51.5+/-7.5 and 39.1+/-7.7% of predicted, respectively. Comparing these parameters between the two groups, only the difference in FEF(25-75) was statistically significant (P<0.01). Valid PPVs and NPVs could not be established for any of the parameters at any level, except for the NPV for FEF(25-75) 50% of predicted or greater, which was 92%. This threshold value resulted in a false negative finding in less than 5% of the patients with hypoxemia. CONCLUSIONS: The results of the present study showed that one in five patients with COPD with FEV(1) 50% of predicted or greater was severely hypoxemic. In such patients, hypoxemia may be excluded, and ABG analysis may not be needed when the FEF(25-75) is also 50% of predicted or greater. The FEV(1), FEV(1)/FVC and PEF parameters failed to predict or exclude severe hypoxemia.

Aged↗
PubMed1999

Contribution of lung function to exercise capacity in patients with chronic heart failure.

BACKGROUND: The importance of exercise capacity as an indicator of prognosis in patients with heart disease is well recognized. However, factors contributing to exercise limitation in such patients have not been fully characterized and in particular, the role of lung function in determining exercise capacity has not been extensively investigated. OBJECTIVE: To examine the extent to which pulmonary function and respiratory muscle strength indices predict exercise performance in patients with moderate to severe heart failure. METHODS: Fifty stable heart failure patients underwent a maximal symptom-limited cardiopulmonary exercise test on a treadmill to determine maximum oxygen consumption (VO2max), pulmonary function tests and maximum inspiratory (PImax) and expiratory (PEmax) pressure measurement. RESULTS: In univariate analysis, VO2max correlated with forced vital capacity (r = 0.35, p = 0.01), forced expiratory volume in 1 s (r = 0.45, p = 0.001), FEV1/FVC ratio (r = 0.37, p = 0.009), maximal midexpiratory flow rate (FEF25-75, r = 0. 47, p < 0.001), and PImax (r = 0.46, p = 0.001), but not with total lung capacity, diffusion capacity or PEmax. In stepwise linear regression analysis, FEF25-75 and PImax were shown to be independently related to VO2max, with a combined r and r2 value of 0. 56 and 0.32, respectively. CONCLUSIONS: Lung function indices overall accounted for only approximately 30% of the variance in maximum exercise capacity observed in heart failure patients. The mechanism(s) by which these variables could set exercise limitation in heart failure awaits further investigation.

Adult↗
PubMed1990

Reduction of sputum Pseudomonas aeruginosa density by antibiotics improves lung function in cystic fibrosis more than do bronchodilators and chest physiotherapy alone.

We evaluated patients with cystic fibrosis (CF) and moderate obstructive lung disease in pulmonary exacerbation in a double-blind placebo-controlled trial to determine the contribution of antibiotic-mediated reduction in sputum bacterial density to clinical improvement. For the first 4 days of study, all patients received bronchodilating aerosols and chest physiotherapy but no antibiotics. During this time, the patients showed significant improvement in mean FVC, FEV1, and maximal midexpiratory flow rate (FEF25-75). In 12 of 13 trials, the patients showed no significant increases in the density of Pseudomonas aeruginosa during these first 4 days. In these 12 trials, the patients were stratified by their initial FVC and randomized to receive either parenteral tobramycin and ticarcillin (n = 7) or placebo (n = 5), in addition to continued aerosol and chest physiotherapy. In the remaining trial, the patient had a significant rise in the density of P. aeruginosa and was assigned to the antibiotic group. During the next 14 days of therapy, the antibiotic group showed significantly (p less than 0.01) greater reductions in log10 colony-forming units (cfu) of P. aeruginosa per gram of sputum and greater increases in FVC, FEV1, and FEF25-75 than did the placebo group. The degree of decrease in log10 cfu P. aeruginosa/g sputum correlated significantly (p less than 0.001) with the degree of improvement in FVC, FEV1, and FEF25-75.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Increased susceptibility to lung dysfunction in female smokers.

The interaction between sex and smoking habits on pulmonary function was examined among 1,149 adults 25 to 59 yr of age in a rural community in Saskatchewan. Pulmonary function tests included FVC, FEV1, maximal midexpiratory flow rate (MMFR), the slope of phase III of the single-breath nitrogen test (delta N2/L), and closing volume as a percent of vital capacity (CV/VC). The data show that after fixing the effects of age, height, and weight by analysis of covariance, the adjusted means of delta N2/L in nonsmokers, ex-smokers, and current smokers were 0.92, 1.10, and 1.60% in women and 0.97, 1.05, and 1.23% in men, respectively. The difference in the adjusted means for delta N2/L between smokers and nonsmokers was larger in women than in men, 0.67% versus 0.26%, respectively. Multiple multivariate analyses show that the regression slopes for the residuals of FEV1, MMFR, and delta N2/L versus pack-years were significantly different between men and women. The regressions of FEV1 and MMFR decreased and the regression of delta N2/L increased with increasing pack-years more rapidly in women than in men. The combined effect of sex and pack-years on pulmonary function was not significant for ex-smokers. These data suggest that cigarette smoking may be more detrimental in its effects on lung function in women than in men.

Adult↗
PubMed1980

Respiratory responses in humans repeatedly exposed to low concentrations of ozone.

The effect of repeated daily exposure to a low concentration of ozone was studied in healthy adult males to answer 2 questions: (1) Is there a cumulative effect of exposure to ozone from day to day, causing an exacerbation of changes in pulmonary function? (2) Does the subject develop resistance or adaptatin to the respiratory effects of ozone? The subjects were exposed for 2 h in an environmental chamber at 35 degrees C and 45% relative humidity to filtered air on day 1, to ozone on days 2 through 4, and to filtered air on day 5. Three groups of subjects were used, each exposed to a different concentration of ozone: group 1 (n = 10), 0.20 ppm of ozone; group 2 (n = 10), 0.35 ppm of ozone; group 3 (n = 8), 0.50 ppm of ozone. There were no acute or cumulative effects of repeated exposure to 0.20 ppm of ozone. With exposure to 0.35 ppm of ozone, there were decrements in forced expiratory parameters on day 2. These changes were greater on day 3, but wre largely absent on days 4 and 5. In group 3, there were marked effects of ozone on pulmonary function on day 2, but these changes were greatest on day 3. Significant effects (although of lesser magnitude) were also observed on day 4. The forced expiratory volume in 1 s decreased 8.7% on day 2, 16.5% on day 3, and 3.6% on day 4. The subjects claimed the most discomfort on day 3; many noted marked improvements on day 4, the third consecutive day of exposure to ozone. Two additional subjects were exposed to 0.50 ppm of ozone for 4 consecutive days. Although effects of ozone on pulmonary function were observed on the first 2 days of exposure, few effects were seen on the third day, and no effect was observed on the fourth day. We conclude that there is some short-term cumulative effect of exposure to concentrations of ozone above the threshold for producing acute respiratory effects. This is followed by a period of resistance or adaptation in which there is a marked lessening of the effect of ozone on pulmonary function and on the subjective feelings of discomfort associated with exposure to ozone.

Adolescent↗
PubMed1983

Epidemiologic health study of workers in an aluminum smelter in British Columbia. Effects on the respiratory system.

A health survey was carried out on all white males in an aluminum smelter in British Columbia. The survey consisted of a medical-occupational questionnaire, spirometry, chest radiography, and environmental monitoring. We have compared the results of a respiratory survey in 713 workers in the office and casting department with no significant exposure to air contaminants (control workers) with those of 797 potroom workers: 495 who spent more than 50% of their working time in the potroom (high exposure) and 302 workers who spent less than 50% of their working time in the potroom (medium exposure). Potroom workers (high) had a significantly greater prevalence of cough and wheeze than did those in the control group, and they had significantly lower mean forced expiratory volume in one second and maximal midexpiratory flow rate than did those in the control group after adjustment had been made for differences in age, height, and smoking habits. Potroom workers (medium) had a slightly greater prevalence of respiratory symptoms and lower lung function than did workers in the control group, but the differences were not significant. We were unable to demonstrate potroom asthma. The levels of total fluoride, gaseous fluoride, particulate fluoride, sulphur dioxide, and total particulates found in the potroom at the time of the study were below the currently accepted threshold limit values, but the levels of benzo-alpha-pyrene were high.

Adult↗
PubMed1968

Regional lung function in patients with bronchial asthma.

The regional distribution of pulmonary ventilation and perfusion and regional alveolar ventilation/perfusion ratios were measured with radioactive xenon ((133)xenon) in 10 patients with asthma in remission. Four subjects had normal ventilation distribution, four had hypoventilation in some regions and normal ventilation in others, and two patients had abnormal ventilation in almost all lung regions. The lung bases were involved most frequently and the middle zones least frequently. Correlation was good between the degree of over-all ventilatory impairment calculated from (133)xenon values and measurement of the maximal midexpiratory flow rate the same day. Regions which were hypoventilated had low ventilation/perfusion ratios and also tended to be hypoperfused. In the eight subjects who had been studied similarly 5 yr previously, changes in regional function correlated in general with changes in over-all function.

Adult↗
PubMed1993

Cyclosporine as possible prophylaxis for obstructive airways disease after allogeneic bone marrow transplantation.

The objective of this study was to evaluate the impact of cyclosporine (cyclosporin A; CyA) prophylaxis for graft-versus-host disease (GVHD) on the development of obstructive airways disease (OAD) after allogeneic bone marrow transplantation (BMT) in leukemic patients. Patients with normal pulmonary function tests (PFTs) prior to BMT were followed with serial PFTs for the development of OAD. Follow-up PFTs were performed at 3, 6, 9, and 12 months, and thereafter at consecutive yearly intervals. Obstructive airways disease was defined as FEV1 less than 80 percent, ratio of FEV1 over the forced vital capacity (FEV1/FVC) less than 80 percent of predicted, maximal midexpiratory flow rate at 50 percent vital capacity less than 65 percent of predicted, or residual volume greater than 120 percent of predicted. In the period prior to CyA prophylaxis for GVHD development (March 1983 to September 1986), 17 (39 percent) of the 44 patients undergoing BMT developed OAD, compared with 2 (4 percent) of 45 in the post-CyA period (September 1986 to March 1990) (chi 2 = 17; p < 0.00005). Age, sex, type of leukemia, severity of GVHD, histocompatibility status, presence of acute GVHD, and sex mismatch between donor and recipient were not associated with development of OAD. Although chronic GVHD was associated with OAD in univariate analysis, a multivariate logistic regression analysis showed that the only significant independent predictor for OAD was the use of CyA. We conclude that CyA is protective against the development of OAD after BMT in leukemic patients.

Adolescent↗
PubMed1985

Reduction of the single breath CO diffusing capacity in cystic fibrosis.

The single breath diffusing capacity of the lung for carbon monoxide (Dsb) was measured using three equations to describe CO uptake separately during inhalation, breath holding, and exhalation in 24 patients with cystic fibrosis and 30 control subjects with similar age and height distributions. Using the control group, we developed two prediction equations for Dsb: one based on height, age, and sex; and another based on alveolar lung volume (VA) to the 2/3 power. We also developed a prediction for Dsb/VA (Kco) based on height. The Dsb as percent predicted (% pred) using either prediction equation decreased with increasing age and height as well as with decreasing % pred maximal midexpiratory flow rate (FEF25-75) in cystic fibrosis patients but not in controls. The Kco (% pred) also decreased in cystic fibrosis with increasing age and decreasing percent pred FEF25-75. We conclude that in patients with cystic fibrosis, Dsb decreases with variables that relate to increasing disease severity (age, height, and increasing airflow obstruction).

Adolescent↗
PubMed1997

Pulmonary ventilatory function decreases in proportion to increasing altitude.

The objective of this study was to examine how pulmonary ventilatory function, including response to bronchodilation, is related to altitude during high-altitude trekking. This cohort experiment consisted of multiple spirometric tests before and after bronchodilation in participants at baseline (1624 m) and at different altitudes (3404-4896 m) during a 2-week trek. The setting was in the Himalayas. Eleven men (ages 22-68 years) and eight women (ages 19-42 years) participated. Interventions were at altitudes of 1624 m to 5265 m; albuterol was administered via Rotahaler. Forced vital capacity (FVC) decreased by an average of 3.8% [95% confidence interval (CI) 1.6 to 6.0] per 1000-m altitude increment. Forced expiratory volume in 1 second (FEV1.0) decreased 3.7% (95% CI 1.9 to 5.5) per each 1000-m altitude increment. Maximal midexpiratory flow rate (FEF25-75%) decreased by 3.6% (95% CI 0.9 to 6.3) per each 1000-m altitude increment. Small, postalbuterol flow increases were present at baseline and at altitude. Ventilatory function returned quickly toward baseline upon descent. One trekker developed cough, dyspnea at rest, extreme weakness, rales, tachycardia, and oxygen desaturation to 71%. His ventilatory measurements did not differ significantly (p > 0.32) from the group means. We concluded that changes in some pulmonary ventilatory parameters (FVC, FEV1.0, and FEF25-75%) were proportional to the magnitude of altitude during a high-altitude trek. These were tolerated well and do not seem to relate to acute mountain sickness. A bronchodilator effect was not increased at altitude.

Adult↗
PubMedDate not supplied

Evidence for obstructive and restrictive lung pathology among tetra-ethyl lead handlers and petrol tanker fillers at a petrochemical industry in Nigeria.

Described here is a computer predicted and computer measured pulmonary function in a randomly selected population sample of 111 men. These consisted of 36 primary school teachers (control), 35 Tetra-ethyl Lead handlers (TEL) and 40 Tanker Loaders (TL) at a petrochemical industry in Warri, Delta State, Nigeria. Productive cough and headache were commoner among the TL (45%, 38%) and the TEL handlers (43%, 31%). TEL handlers were 5 times likely to develop insomnia and other sleep disturbances than the control group. TL were more than 3 1/2 times more likely to develop nervousness than the control group. Measured FEF25-75% was significantly lower than its predicted value among the TEL handlers (56%) and TL (55%) when compared with the control group (36%) (P < 0.05 respectively). Although there were distinct reductions in the measured values of FEF75-85% among the TEL handlers (41%) and the TL (40%) compared to the control group (28%), this difference did not reach a level of significance when the TEL or the TL were compared individually to the control group. Predicted and measured forced mid expiratory flow time (FMFT) was not significantly varied among the cases and the control. There was statistically significant disparities (P < 0.005) in the values of predicted and measured maximum voluntary ventilation (litres) of the TEL handlers (47%) and of the TL (46%) compared with that of the control group (29%). The data suggest obstruction of the big and small airways of those occupationally exposed at a petrochemical factory in Nigeria especially the tetra-ethyl lead handlers and the tanker loaders. This data also suggests that pulmonary impairment may lead to an increased respiratory absorption of lead in its organic form. Efforts should be made to ascertain the degree of impairment and to treat the affected workers.

Adult↗
PubMed1975

Medical surveillance for occupational respiratory diseases.

Three simple procedures should be used to monitor industrial populations for the development of respiratory disease: (1) History, (2) chest x-ray, and (3) spirometry. The history should be complete and include occupational as well as medical information. Only a P-A x-ray examination of the chest is necessary. Accurate performance of spirometry with reliable equipment can provide useful evidence of physiologic impairment. Serial test results from each employee should be carefully compared to best assess the early development of occupational respiratory disease.

Forced Expiratory Volume↗
PubMed1999

[Changes in the pulmonary function of factory workers exposure to terephthalic acid].

The pulmonary function was examined in 140 workers exposed to terephthalic acid(TPA) and 70 controls in the same residence area as non-exposure workers. The exposed workers exhibited significant decrease in MVV, PEFR, V75, PEFR/H and V75/H(P < 0.05) in comparison with the controls. The decrease was found to be associated with increased TPA concentration by multiple regression analysis. The results of life table method analysis suggested that there was an exposure level-response relationship between accumulative TAP dust exposure and lower FEV1. According to the results reported here, an exposure limit for TPA dust was proposed to be 4.30 mg/m3.

Adult↗
PubMed1986

Celiprolol, atenolol and propranolol: a comparison of pulmonary effects in asthmatic patients.

Celiprolol, a new beta-adrenoceptor antagonist, blocks serotonin- and methacholine-mediated bronchoconstriction in animals, even in the presence of propranolol. In two, randomized, placebo-controlled, 5-way crossover trials, the pulmonary effects of celiprolol 200 and 400 mg, propranolol 40 mg and atenolol 100 mg were compared in 34 asthmatic patients. Pulmonary function was measured after single doses of each agent, and again following subsequent, graded doses of albuterol or isoproterenol aerosol. Changes in one-second forced expiratory volume (FEV1) and maximal midexpiratory flow rate (FEF25-75) prior to albuterol or isoproterenol were positive after placebo and both doses of celiprolol. Propranolol, and to a lesser extent, atenolol, caused significant reductions in both measures of pulmonary function. Overall changes in FEV1 following each drug plus isoproterenol or albuterol were positive, in the rank order, celiprolol approximately placebo greater than atenolol greater than propranolol. Propranolol pretreatment caused a significant reduction in the effect of bronchodilator. Unlike atenolol and propranolol, celiprolol was highly bronchosparing and did not antagonize sympathomimetic bronchodilators.

Adrenergic beta-Antagonists↗
PubMed1979

Protease inhibitor variants in children and young adults with chronic asthma.

The results of systematic medical histories and pulmonary function tests on 26 children and young adults, 10 with Pi variant alpha1-antitrypsin phenotypes and 16 Pi normals, are reported. These subjects were selected from 57 consecutive patients who had chronic asthma. The incidence of Pi variants was 20.4% among 46 Caucasian subjects (ages seven to 21 years). The Pi variant patients required more bronchodilators and long-term corticosteroid therapy. Among the parents and siblings, 50% of those with abnormal Pi type had chronic obstructive lung disease. Grandparents of the Pi abnormal probands had greater incidence of chronic obstructive lung disease (P less than 0.05). Baseline specific airways conductance and maximal midexpiratory flow rates did not discriminat between the two groups. However, bronchodilator inhalation showed the Pi variant group to be significantly less responsive than the Pi normal group. Pi heterozygous state, particularly Pi MZ, should be considered when a young person with chronic asthma is unresponsive to adequate doses of bronchodilators and needs prolonged use of corticosteroids.

Adolescent↗
PubMedDate not supplied

Tests of minimal obstruction in the small airways: interrelationships and physiologic significance.

Several technics have become popular to detect airway obstruction in the small (less than 2 mm diameter) peripheral bronchi which appear to be the site of the early lesions in chronic obstructive pulmonary disease (COPD). These include determining maximal midexpiratory flow rate (MMFR) from the expiration spirogram, maximum expiratory flows at low lung volumes from the maximum expiratory flow-volume (MEFV) curve, a comparison of flow-volume curves during air and helium/O2 breathing, demonstration of frequency dependence of compliance, and the measurement of closing volume (CV). This discussion attempts to interpret the literature relative to these tests, examining their physiologic basis and clinical significance while relating them to the standard spirometric tests. The aim is to provide the clinical anesthesiologist with a better understanding of the information they provide, since their physiologic basis relates well to the many aspects of abnormal lung function which appear during anesthesia and the entire perioperative period.

Airway Obstruction↗