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PubMed1989

Inverse correlation of expiratory lung flows and sputum eosinophils in status asthmaticus.

Seventy-six consecutive patients admitted to Los Angeles County General Hospital with acute asthma were studied. Blood and sputum smears for cell counts were obtained on all patients within 12 hours of admission. Fifty-one (67%) patients were able or willing to perform spirometry and flow/volume curves in the first 24 hours of hospitalization. The severity of airway obstruction as assessed by forced expiratory volume in one second (FEV1), maximum mid-expiratory flow rate (MMFR), and forced vital capacity (FVC) was compared with blood and sputum eosinophil counts. Although there was no relation between the blood eosinophilia and airway obstruction, an inverse relationship between the number of eosinophils in the sputum and airway flow rates was observed. Higher percentages of sputum eosinophils were associated with diminished flow rates. We believe that sputum eosinophils may be helpful in the initial assessment of severe bronchial asthma.

Adolescent↗
PubMed1982

Bronchodilatation, lung recoil, and density dependence of maximal expiratory flow.

Using normal human subjects we have measured maximal expiratory flow rates with air (Vmaxair) and after a washin of 80% He-20% O2 (VmaxHeO2) and static elastic recoil pressures of the lung [Pst(L)] both before and after administration of a beta-agonist, terbutaline. The effects of inhaled drug were compared with those of the subcutaneously administered agent, each given in doses to produce maximal bronchodilatation as assessed by increases in Vmaxair in the mid-vital capacity. Although there was a significant yet modest decrease in Pst(L) only after injection of the agent, density dependence (DD), assessed as the ratio of VmaxHeO2 to Vmaxair, increased significantly and comparably after either route of administration. A modest decrease in Pst(L), therefore, did not affect the changes in DD.

Adolescent↗
PubMed1980

The immediate effect on lung function of smoking filtered and nonfiltered cigarettes.

We measured and compared the effect of smoking a filtered and a nonfiltered cigarette on instantaneous maximal expiratory flow rates (Vmax50 and Vmax25) and airway resistance (Raw). We found a significant increase in Raw after both cigarettes, and a small decrease in Vmax50 after smoking the nonfiltered cigarette. The change in Vmax50 after smoking the filtered cigarette was not significant. We suggest, on the basis of these data, that filtered cigarette smoke reduces some of the constituents that cause bronchoconstriction in the large and central airways.

Adolescent↗
PubMed1975

Reproducibility of dynamic compliance and flow-volume curves in normal man.

To evaluate methods proposed for the early detection of small airways obstruction. we have compared the precision of the forced expiratory flow-volume curve and of measurements of the frequency dependence of lung compliance in normal subjects, in 10 of whom these measurements were made on four occasions, and in 5 on two occasions. The maximal expiratory flow rate was highly reproducible, revealing consistent differences between these normal subjects, particularly when measured at 60% of TLC and corrected for differences in body size. The frequency-dependence measurements, expressed as the slope of the regression line relating dynamic compliance to frequency, showed much greater variation between repeated measurements in the same subject. Comparison with earlier published accounts is difficult in view of lack of quantitative data, but the variability between single measurements on different normal subjects appears to be similar to that which we have found when the results are expressed in a comparable manner. Dynamic compliance at a frequency of 1 Hz lay between 48% and 141% of the value obtained by extrapolation to zero frequency.

Adult↗
PubMed1982

Acute respiratory effects of exposure to diesel emissions in coal miners.

A study was conducted to determine if acute respiratory effects, measured in terms of changes in forced vital capacity (FVC), forced expiratory volume in one second (FEV1), and maximal expiratory flow rate at 50% of forced vital capacity (Vmax50), were related to exposure to diesel emissions in coal miners. Sixty coal miners exposed to diesel emissions and 90 miners not exposed were tested before and after a work shift for ventilatory function changes. Significant work shift decrements in ventilatory function did occur in miners in both groups who smoked cigarettes, but there were no significant differences in the ventilatory function changes between those miners exposed to diesel emissions and those not exposed either in the aggregate or under control by smoking status.

Adult↗
PubMed1999

Major genetic effects on airway-parenchymal dysanapsis of the lung: the Humboldt family study.

We examined familial resemblance and performed segregation analysis for the maximal expiratory flow rate at 50% of vital capacity (Vmax50) and the ratio of Vmax50 to forced vital capacity (FVC), based on data from 309 nuclear families with 1,045 individuals in the town of Humboldt, Saskatchewan, in 1993. Vmax50 is considered as an index of airway function and Vmax50/FVC is considered as an index of airway-parenchymal dysanapsis. Both Vmax50 and Vmax50/FVC were preadjusted for host characteristics (age, height, and weight), environmental factors, and history of respiratory symptoms and diseases in four separate groups (mothers, fathers, daughters, and sons). Both Vmax50 and Vmax50/FVC showed low father-mother correlations and significant parent-offspring and sibling-sibling correlations. Segregation analysis indicated that for residual Vmax50, the model of no-parent-offspring transmission with possible heterogeneity between two generations fitted the data as well as did the general model with arbitrary transmission probabilities. The Mendelian hypothesis for Vmax50 was rejected, which was consistent with our previous findings for other indexes of airway function. For residual Vmax50/FVC, however, a single locus explained all the familial resemblance and both no-parent-offspring-transmission hypotheses [tau(AA) = tau(AB) = tau(BB) = qA and tau(AA) = tau(AB) = tau(BB)] were rejected. The study provides evidence for a single locus influencing airway-parenchymal dysanapsis.

Consanguinity↗
PubMedDate not supplied

A normal FEV1/VC ratio does not exclude airway obstruction.

BACKGROUND: A decreased forced expiratory volume in 1 s/vital capacity (FEV(1)/VC) ratio is the hallmark of the definition of airway obstruction. We recently suggested that a lung function pattern, we called small airways syndrome (SAOS), has a normal FEV(1)/VC and total lung capacity (TLC) and reflects obstruction of small airways. OBJECTIVES: To substantiate our hypothesis we measured and compared lung function tests including maximal expiratory flow rates (MEFR), sensitive indicators of airway obstruction, in SAOS subjects and in matched controls. METHODS: We selected 12 subjects with the pattern of SAOS, but without chronic lung or heart disease (average age: 40.7 +/- 7.8 years) and 36 age-matched subjects with normal lung function (42.8 +/- 6.3 years). We measured static and dynamic lung volumes, MEFR and lung diffusing capacity (DL(CO)). RESULTS: SAOS subjects were heavier smokers (p < 0.05) and body mass index was less than in control subjects (p < 0.01). Both FEV(1)/VC ratio and TLC were comparable in the two groups. However, FEV(1), VC, DL(CO), and MEFR were lower and residual volume (RV) and RV/TLC ratio were higher (p < 0.05) in the SAOS group than in the control one. Furthermore, the MEFR curve of the SAOS group was displaced to the left without any change in slope, suggesting premature airway closure. CONCLUSION: Our results suggest that a normal FEV(1)/VC ratio does not exclude airway obstruction. A decrease of FEV(1), provided TLC is normal, reflects small airway obstruction.

Adult↗
PubMed1984

Verofylline, a methylxanthine bronchodilator, in asthma.

Verofylline, a long-acting polysubstituted methylxanthine bronchodilator, was taken orally by eight adult patients with asthma in a double-blind, crossover tolerance study. Peak expiratory flow, forced vital capacity, and its subdivisions were measured weekly 2, 4, and 6 hr after oral dosing with drug or placebo. Peak drug activity developed between 4 and 6 hr after dosing. Subject tolerance was good at the doses used. Dose-response curves for mean forced expiratory volume in one second, peak expiratory flow rate, and forced expiratory flow at the end of 4 hr were greater after 0.05 mg/kg verofylline than after placebo or higher doses of verofylline. Mean percent change in forced vital capacity remained increased as long as 6 hr after 0.15 mg/kg active drug. Verofylline was not very effective as a bronchodilator at the doses used.

Administration, Oral↗
PubMed2004

Effect of salmeterol on the ventilatory response to exercise in chronic obstructive pulmonary disease.

This study examined the effects of bronchodilator-induced reductions in lung hyperinflation on breathing pattern, ventilation and dyspnoea during exercise in chronic obstructive pulmonary disease (COPD). Quantitative tidal flow/volume loop analysis was used to evaluate abnormalities in dynamic ventilatory mechanics and their manipulation by a bronchodilator. In a randomised double-blind crossover study, 23 patients with COPD (mean +/- SEM forced expiratory volume in one second 42 +/- 3% of the predicted value) inhaled salmeterol 50 microg or placebo twice daily for 2 weeks each. After each treatment period, 2 h after dose, patients performed pulmonary function tests and symptom-limited cycle exercise at 75% of their maximal work-rate. After salmeterol versus placebo at rest, volume-corrected maximal expiratory flow rates increased by 175 +/- 52%, inspiratory capacity (IC) increased by 11 +/- 2% pred and functional residual capacity decreased by 11 +/- 3% pred. At a standardised time during exercise, salmeterol increased IC, tidal volume (VT), mean inspiratory and expiratory flows, ventilation, oxygen uptake (VO2) and carbon dioxide output. Salmeterol increased peak exercise endurance, VO2 and ventilation by 58 +/- 19, 8 +/- 3 and 12 +/- 3%, respectively. Improvements in peak VO2 correlated best with increases in peak VT; increases in peak VT and resting IC were interrelated. The reduction in dyspnoea ratings at a standardised time correlated with the increased VT. Mechanical factors play an important role in shaping the ventilatory response to exercise in chronic obstructive pulmonary disease. Bronchodilator-induced lung deflation reduced mechanical restriction, increased ventilatory capacity and decreased respiratory discomfort, thereby increasing exercise endurance.

Administration, Inhalation↗
PubMed1998

Pulmonary infection with Mycobacterium avium-intracellulare leads to air trapping distal to the small airways.

To clarify the structure and function of the airways in Mycobacterium avium-intracellulare (MAI) infection, we performed pulmonary function tests and high-resolution computed tomography (HRCT) of the thorax in female patients 61 +/- 9 yr of age (n = 12) with pulmonary MAI infection without predisposing lung disease and compared their data with those of normal female volunteers 54 +/- 8 yr of age (n = 9). We calculated the E/I ratio, i.e., the average ratio of HRCT number at full expiration to that at full inspiration, as an index for the evaluation of air trapping distal to the small airways. Patients showed significant increases in residual volume and slope of phase III (DeltaN2) of the single-breath nitrogen test, and significant decreases in flow at 50 and 25% of FVC, suggesting hyperinflation and obstruction of the small airways. HRCT of patients revealed the small nodules and ectasis of bronchioles and small bronchi located mainly in segments (S) S2, S3, S4, and S5. The E/I ratio was significantly elevated in patients, and especially higher in the upper lung field than in the lower lung field, suggesting air trapping distal to the small airways. The difference of E/I ratio between the upper and lower field is probably related to the segmental distribution of CT abnormalities. These findings suggest that MAI infection can lead to air trapping distal to the small airways.

Airway Obstruction↗
PubMed1985

[Value of the maximal expiratory flow-volume diagram in a longitudinal study].

In a 4-year follow-up we have measured the maximal expiratory flow-volume curve in a random sample of the population of a hydrogen chloride air-polluted area. At the first investigation the pressure transducer of our pneumotachograph had shown an unsatisfactory frequency characteristic. Therefore the initial flow of the flow-volume curve (PEF and MEF 75) were underestimated. The values for asymptomatic non-smokers of the restudy were in good accordance with reference values of other authors. On both occasions we found significant differences between smokers and non-smokers and between persons with and without bronchitis. The lung function data correlated also with tobacco consumption. There was no evidence for superiority of the maximal expiratory flow rates over the conventional spirometric parameters FEV1 and FVC.

Adult↗
PubMed1984

Small airways changes in workers exposed to asbestos.

Although restriction is considered the classic pulmonary function profile of asbestosis, studies suggest that obstruction of the peripheral airways not revealed by standard spirometry is equally frequent and indicative of peribronchiolar fibrosis. We recorded flows and volumes from maximal expiratory flow volume (MEFV) curves, closing volume data and the phase III slope of the alveolar plateau for 610 litigants, 575 men and 35 women, exposed to asbestos for varying periods in a single workplace in northern New Jersey. Smokers (260) included current smokers and subjects who had stopped within the previous 10 years; nonsmokers (350) had either never smoked or had given up for more than 10 years. Analyses were made for both groups according to years worked. Compared to predicted, smokers and nonsmokers had significantly higher closing capacities (p less than 0.01) and delta N2% (p less than 0.001) means, and lower forced vital capacity (FVC), forced expiratory volume for the first second (FEV1.0, maximal expiratory flow rate (MEFR) and peak expiratory flow rate (PEFR) functions (p less than 0.05); the flow rate after 75% of the FVC had been exhaled (FEF75%) values were significantly reduced (p less than 0.01) only for workers exposed for more than 30 years. The change from predicted was significantly more rapid for smokers, compared with nonsmokers, for FVC, FEV1.0, PEFR, MEFR and FEF75% means, while the increase in closing capacity (CC) was twice as rapid for nonsmokers and the two groups did not differ in their mean rates of rise for delta N2%. CC and the slope of the alveolar plateau appeared to be the measures best able to discriminate between the data for both smoking and nonsmoking asbestos workers and their lung function prediction means.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed2001

Maximal expiratory flow patterns after single-lung transplantation in patients with and without chronic airways obstruction.

BACKGROUND: A biphasic-plateau pattern in the maximal expiratory flow-volume (MEFV) curve has been described after single-lung transplantation (SLT) in patients with chronic airways obstruction (CAO). It has been theorized that this pattern is either related to stenosis at the anastomotic or subanastomotic site, or the sum of the airflow contribution from the native lung with airways obstruction and transplanted lung. SUBJECTS AND METHODS: We analyzed data in 16 patients with CAO who had undergone transplantations (5 men, 11 women; mean age [+/- SD], 53.8 +/- 4.9 years), and 9 patients with pulmonary vascular disease (PVD) without airways obstruction who had undergone transplantations (2 men, 7 women; mean age, 35.4 +/- 11.4 years). RESULTS: In the patients with PVD, there were no significant changes in static or dynamic lung volumes or in the MEFV curve after SLT. In the patients with CAO, indexes of airways obstruction improved significantly after SLT, and the typical biphasic-plateau pattern developed in the MEFV curve. In one patient with CAO who required pneumonectomy of the native lung after SLT, the biphasic pattern was absent. CONCLUSIONS: These results support the view that this MEFV pattern is a result of airflow from the native and transplanted lungs in patients with CAO. In addition, the results show that in patients with no prior airways obstruction, SLT does not alter static or dynamic lung volumes or maximal expiratory flow rate.

Adult↗
PubMed1980

Upper and lower airway hyperreactivity in recurrent croup.

Seventeen children with recurrent croup, who had their last episode within the previous 12 months, were evaluated clinically by allergy skin tests, pulmonary function tests, and a histamine inhalation challengae. Fourteen showed airway hyperreactivity. Flow-volume loops were obtained after a positive histamine response and compared with post histamine tracings of children with asthma and health control subjects. Children with recurrent croup as well as those with asthma showed a significantly greater fall in maximal expiratory flow rates than that shown in healthy control subjects. Those recurrent croup also had a significantly greater fall in maximal inspiratory flow rates when compared to those with asthma and to the control subjects. A specific type airway hyperreactivity suggestive of involvement of both upper and lower respiratory tract was seen in children with recurrent croup.

Adolescent↗
PubMed1985

Carbon monoxide diffusing capacity: a reliable indicator of bleomycin-induced pulmonary toxicity.

Seventy-seven untreated patients with germ-cell tumors, of whom 20 had no pulmonary involvement, no clinical or radiological evidence of pulmonary disease, received 6 courses of cisplatin, vinblastine and bleomycin. Pulmonary function tests were performed before, every 3 weeks during treatment, and once a month from then on. The carbon monoxide diffusion capacity tests were normalized with respect to the actual hemoglobin concentration. During treatment a nonsignificant decrease (P greater than 0.05) was seen in the flow volume relationships, but as it was reversible it was attributed to the strenuous treatment. In contrast a significant decrease of 35% (P less than 0.01) in the corrected carbon monoxide diffusion capacity was seen in 15 of 18 evaluable patients with neither clinical nor radiological signs of pulmonary toxicity. The decrease was correlated to the increasing dose of bleomycin (r = 0.63).

Adolescent↗
PubMed1981

Pulmonary mechanisms and work of breathing at maximal ventilation and raised air pressure.

Pulmonary ventilation (V) and the interrelationships of airflow, transpulmonary pressure, and lung volume during inspiration and expiration were studied in eight healthy subjects who performed maximal exercise (MEx; 140% VO2 max), 15-s maximal voluntary ventilation (MVV), and forced inspiratory and expiratory vital capacity (FVC) maneuvers at 1, 3, and 6 ATA. Maximal exercise ventilation and MVV amounted to 149 +/- 7 (mean +/- SE) and 193 +/- 9 l . min-1, respectively, at 1 ATA and were both reduced by approximately 37% at 3 ATA and by 50% at 6 ATA. Expiratory peak flows during MEx and MVV were equal to the maximal flows obtained during FVC at comparable lung volumes, whereas inspiratory peak flows during MEx were 20% less than the FVC flows. Despite a sixfold increase in gas density, the rate of mechanical work of breathing decreased when the pressure was raised to 6 ATA, during MEx from 8 +/- 1 to 6 +/- 1 W, and during MVV from 28 +/- 5 to 18 +/- 3 W. With increasing gas density there was a shift of lung volumes in the inspiratory direction with consequent reductions of inspiratory-to-expiratory flow ratios. We conclude that depletion of energy stores in the inspiratory muscles contributed to limiting V during MEx at raised air pressure.

Adult↗