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Relation of lung function, maximal inspiratory pressure, dyspnoea, and quality of life with exercise capacity in patients with chronic obstructive pulmonary disease.

BACKGROUND: Several studies have shown that both objective and subjective measurements are related to exercise capacity in patients with chronic obstructive pulmonary disease (COPD). In this study the relative contribution of lung function, maximal inspiratory pressure, dyspnoea, and quality of life to the performance in a walking distance test and a bicycle ergometer test was investigated. METHODS: Static lung volumes, forced expiratory volume in one second (FEV1), inspiratory slow vital capacity (IVC), transfer factor for carbon monoxide (TLCO) divided by the alveolar volume (TLCO/VA), static compliance (Cst), and maximal inspiratory peak pressure (PImaxPOES) were measured in 40 patients with COPD with severe airways obstruction (mean FEV1 44% predicted, mean FEV1/IVC 37% predicted). Quality of life was assessed by the Chronic Respiratory Questionnaire (CRQ) and dyspnoea by the Borg category scale. Exercise capacity was measured by both a six minute walking distance (test) and a maximal work load of the bicycle ergometer test (Wmax). RESULTS: Spirometric values and maximal inspiratory pressure were modestly correlated with both the six minute walking test and Wmax, r values ranging from 0.50 to 0.58. The TLCO was strongly correlated with the six minute walking test (r = 0.62) and with Wmax (r = 0.78). Quality of life showed no correlation with exercise capacity, while there was a correlation between dyspnoea and the six minute walking test (r = -0.41). Backward linear regression analysis selected TLCO and PImaxPOES as the most significant determinants for exercise performance. They explained 54% and 69% of the variance in the six minute walking test and Wmax, respectively. CONCLUSIONS: The results show that exercise capacity in patients with COPD with severe airways obstruction is more strongly related to inspiratory muscle strength and lung function than to dyspnoea and quality of life. The significant correlation between dyspnoea and the six minute walking test suggests that subjective variables are more strongly related to walking tests than to bicycle ergometer tests.

Aged↗

Asthma and respiratory irritants (ozone).

Asthmatics appear to be more susceptible to the effects of air pollutants than nonasthmatics. The present studies were undertaken to examine the effects of exposing asthmatics to ozone concentrations that occur in the environment. Seventeen well-documented male and female asthmatics have been exposed for 2 hr in an environmental chamber to 0.25 ppm of ozone on one occasion (ozone) and to air on another occasion (air). Effects were assessed by measurements of pulmonary function obtained prior to (0 hr), every half-hour during and at the end of all exposures (2 hr). Paired t-test analysis of lung volumes, forced expiratory volume in 1 sec (FEV1.0), and maximum expiratory flow rates at 50% of vital capacity (V50%VC) showed no significant changes (p greater than 0.05) when the following comparisons were made: 0 hr air vs 0 hr ozone, 0 hr air vs. 2 hr air, 0 hr ozone vs. 2 hr ozone, 2 hr air vs. 2 hr ozone. There was variability in severity of asthma and pulmonary function status; most subjects were taking some form of medication at the time of study. Some asthmatics showed no change or improvement with both air and ozone and others developed greater reductions in pulmonary function with ozone than with air. Approximately one-third of the asthmatics demonstrated greater changes in V50%VC with exposure to 0.25 ppm of ozone relative to air exposure. These studies indicate that acute exposures to ozone at realistic concentrations in the environment can produce adverse responses in some asthmatics.

Adult↗

Risk of acute bronchospasm and bronchial hyperreactivity from inhaled acid aerosol in healthy subjects: randomized, double-blind controlled trial.

AIM: To determine the risk of developing acute bronchial spasm and bronchial hyperreactivity in healthy subjects after inhaling hydrochloric acid aerosol of different pH, since various characteristics of inhaled aerosol, particularly its acidity, contribute to the reduction in lung function in patients with a pre-existing disease. METHODS: Randomized, double-blind, placebo-controlled trial included 79 healthy volunteers. After submitting a written consent, they were randomized in 4 groups with approximately equal number of participants. Each group was exposed to acid aerosol of different pH. The respiratory lung function expressed by forced expiratory volume (FEV1), forced expiratory flow at 50% (FEF50), 75% (FEF25), and between 25% and 75% of vital capacity (FEF25/75), and non-specific bronchial reactivity were measured after inhalation of hydrochloric acid aerosol of pH 7.0, pH 5.0, pH 3.0, and pH 2.0 and compared with baseline values. Twelve subjects, who reached the threshold doses in both bronchial challenges, were tested again after receiving a systemic beta-blockade with a single oral dose of propranolol. RESULTS: Significant bronchospasm developed after the inhalation of hydrochloric acid aerosol of pH 5.0, 3.0, and 2.0. After the inhalation of aerosols of pH 5.0 and pH 2.0, all parameters of respiratory lung function (FEV1, FEF50, FEF25, and FEF25/75) significantly decreased. After the inhalation of aerosol of pH 3.0, all parameters significantly decreased except for FEF25, which showed no significant difference (1.84+/-0.46 before vs 1.58+/-0.49 after inhalation; p=0.07). The inhalation of hydrochloric acid aerosol had no significant effect on the level of non-specific bronchial reactivity irrespective of its pH. Eight out of 12 subjects tested again after pretreatment with propranolol and with no significant change in the heart rate showed no change in non-specific bronchial reactivity in comparison with the 4 subjects who reacted with a significant decrease in the heart rate (>10%), as well as in non-specific bronchial reactivity (p=0.023). CONCLUSION: Inhalation of acid aerosol in healthy subjects induced a bronchial spasm, but had no effect on non-specific bronchial reactivity except in subjects under systemic adrenergic inhibition.

Adrenergic beta-Antagonists↗

Tests of small airway function in black smokers and nonsmokers.

Tests of small airway function (closing volume, forced expiratory flow in the middle half of the vital capacity, specific airway conductance, and peak expiratory flow) and routine spirometric tests (forced vital capacity, forced expiratory volume in one second, and residual volume) were performed in 848 adult black subjects of both sexes. The group included 422 smokers and 426 nonsmokers. No significant difference was found between smokers and nonsmokers for any of the tests, although some values were higher for men than for women. These findings suggest that reported abnormalities in small airway function in smokers in the general population may not be applicable to black smokers. This may be an important finding in ethnic variability in the incidence of chronic obstructive pulmonary disease.

Adult↗

The influence of ketotifen and aminophylline on the central and peripheral airways.

In a double-blind study we compared the effect of 2 mg ketotifen (Zaditen) daily and 1050 mg aminophylline daily for 6 months in two groups of altogether 24 patients with bronchial asthma and a chronic obstruction of the airways. Lung function tests were done in regular intervals to investigate the effects of the drugs on the central airways resistance, thoracic gas volume, forced expiratory volume of the first second and inspiratory vital capacity--and the peripheral airways closing volume, flow of iso and the flow volume curve. Ketotifen reduced the obstruction of the central and of the peripheral airways. Aminophylline showed a less pronounced effect on the obstruction of the central airways and did not influence the peripheral airways. Number and severity of asthmatic attacks, cough, dyspnea and expectoration improved with both drugs. From our results we conclude that ketotifen reduces the obstruction of the central airways and also may exert a direct influence on the small airways. This drug therefore seems to possess special antiasthmatic effects. In contrast aminophylline acts as a rapidly effective bronchodilating agent with no detectable effects on the peripheral airways.

Adult↗

[Analysis of ventilation parameters before and after fiber optic bronchoscopy in patients with atopic bronchial asthma and chronic obstructive pulmonary diseases].

Bronchial asthma and chronic bronchitis in a stable period of the disease could be an indication for diagnostic bronchofiberoscopy. The aim of the authors of this article is to assess whether bronchoscopy may be safely used either as diagnostic or therapeutic procedure. 21 patients (age 33-46), 13 with atopic bronchial asthma and 8 with COPD took part in this study. The measurements were carried out one day before and 3 hours after the bronchoscopy. The following parameters: Forced Vital Capacity (FVC), Forced Expiratory Volume (FEV1), Forced Expiratory Flow (FEF25, FEF50, FEF75) and Resistance of Airways (R aw) were taken into consideration. It was shown that bronchofiberoscopy could be performed safely in these patients and did not lead to woersing ventilation parameters. Bronchospasm was not observed during the study. Moreover the increase in FEF50, FEF75 and R aw were observed. This significant decrease of amount of bronchial discharge could serve as an explanation of this phenomenon.

Adult↗

Lung function in Indian twin children: comparison of genetic versus environmental influence.

The relative contributions of genetic and environmental components in the variability of lung function measurements were studied in 54 twin pairs. Thirty pairs of monozygote (MZ) twins and 24 pairs of dizygotic (DZ) twins were examined. All measurements were made with 9-litre closed-circuit-type expirographs using standard spirometric techniques, except for peak expiratory flow rate (PFER) which was recorded with a Wright peak flow meter. Within-pair variances for inspiratory capacity (IC), vital capacity (VC), forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1), forced mid-expiratory flow (FEV25-75%), forced end-expiratory flow (FEF75-85%), maximum expiratory flow (FEF200-1200ml), forced maximum voluntary ventilation MVVF) and PEFR were significantly smaller (p < 0.01) in MZ twins than in DZ twins. Tidal volume (VT), inspiratory reserve volume (IRV), expiratory reserve volume (ERV), forced expiratory volume in 1 second as a percentage of forced vital capacity (FEV1%), and forced expiratory time (FET) were not significantly different. Within-pair correlations were all higher in MZ than DZ twins. All measurements except for VT and PEFR showed high levels of heritability (23-99%). All measurements were positively and significantly correlated with physical characteristics such as weight, standing height, surface area, arm-span, chest circumference and age, except FEV1% and FET. Residual values adjusted for physical characteristics showed similar results to unadjusted values in most cases. These data indicate that major lung function measurements are possibly influenced more by genetic than environmental factors. Genetically influenced measurements show higher levels of heritability estimates and suggest that genetic determination of lung function is possibly independent of the influence of physical characteristics.

Adolescent↗

An evaluation of the initial treatment of acute asthma.

Two treatment regimens for the initial treatment of acute asthma in 50 patients between the ages of 12 and 20 years seen in the emergency room were evaluated. The treatments were randomized such that 26 patients received 2.5 mg of the beta 2-agonist fenoterol by nebulizer and 24 patients received 0.3 mg of epinephrine followed by 0.75 mg of Sus-Phrine. Clinical assessment and spirometry were performed over a two-hour period. Both groups responded within ten minutes and peak improvement was reached within one hour. Peak expiratory flow and clinical score were better following fenoterol treatment in the first hour (P less than .05). The one-second forced expiratory volume and the forced expiratory flow in the middle half of the vital capacity were greater at 20 minutes with fenoterol (P less than .05). Those with more severe obstruction (forced expiratory volume less than 30%) receiving aerosol therapy also had significantly greater improvement in the first 20 minutes compared with those who received injections. Four patients failed to respond to epinephrine whereas all patients showed improvement with fenoterol (P less than .05). These results demonstrated that an inhaled beta 2-agonist is effective in the initial treatment of acute asthma in children, regardless of severity, and avoids the need for injections.

Acute Disease↗

Peripheral airways obstruction in patients with rhinitis.

Nine young lifetime nonsmoking patients with symptoms of rhinitis but without any history of asthma or wheezing and nine age-matched healthy lifetime nonsmoking control subjects were studied with respect to subdivisions of lung volume, forced vital capacity, forced expiratory volume (1.0 sec), and flow-volume curves breathing air, and also breathing a mixture of 80% helium--20% oxygen (He-O2) from which were obtained airflows at 50% VC (Vmax50), the percentage increase in Vmax50 breathing He-O2 as compared to air (deltaVmax50) and the point where He-O2 and airflow-volume curves became identical (Visov). No significant differences between the two groups in age, subdivisions of lung volume or forced expiratory airflow rates were recorded. However, deltaVmax50 was significantly lower in the patients (16.4 +/- 12.0) compared to the controls (47.7 +/- 16.4) (p less than .001) and Visov was higher in the patients (28.4 +/- 14.9) as compared to the controls (14.4 +/- 7.6) (p less than .01). After bronchodilator therapy Vmax50 increased in the control subjects (p less than .005) but not in the patients and deltaVmax 50 decreased in the control group but was unchanged in the rhinitis patients. These results suggest that patients with rhinitis who have normal airflow rates may have peripheral airways obstruction not readily reversible with bronchodilators.

Adult↗

Flow-volume loop changes reflecting respiratory muscle weakness in chronic neuromuscular disorders.

In order to identify the changes in pulmonary function and in the flow-volume loop due to respiratory muscle weakness, two groups of 10 nonsmokers with stable, chronic neuromuscular disease but without respiratory symptoms were studied: one without (Group 1) and one with (Group 2) respiratory muscle weakness as assessed by measurement of maximal static inspiratory and expiratory pressures. In Group 1, pulmonary function was normal except for increased ratio of one-second forced expiratory volume to forced vital capacity and forced expiratory flow at 25 to 75 percent forced vital capacity, which may reflect increased elastic lung recoil. Group 2 had mild volume restriction, appropriate for the degree of respiratory muscle weakness, and reduced inspiratory and expiratory flow rates. Pulmonary function was significantly more disturbed in Group 2 than in Group 1, and correlated well with maximal static inspiratory and expiratory pressures. Analysis of the flow-volume loop configuration revealed that four parameters describing effort-dependent portions were significantly related to maximal static inspiratory pressure and maximal static expiratory pressure. These parameters were peak expiratory flow, the slope of the ascending limb of the maximal expiratory curve, a drop of forced expiratory flow near residual volume, and forced inspiratory flow at 50 percent of vital capacity. A flow-volume loop score obtained from these four parameters was significantly higher in Group 2 than in Group 1 (2.8 +/- 1.03 versus 1.1 +/- 1.37; p less than 0.01). A flow-volume loop score of 2 or more had 80 percent specificity and 90 percent sensitivity in predicting respiratory muscle weakness in these patients with chronic neuromuscular disease. These data suggest that sensitive assessment of the flow-volume loop configuration as part of routine pulmonary function testing may help to suspect and identify respiratory muscle weakness.

Chronic Disease↗

Ministernotomy versus complete sternotomy for coronary bypass operations: no difference in postoperative pulmonary function.

OBJECTIVES: Less-invasive approaches in cardiac operations offer certain cosmetic advantages, but it is unclear whether there are additional positive effects with regard to the postoperative recovery of patients. The aim of this prospective and randomized study was to ascertain whether partial inferior midline sternotomy can improve pulmonary function, one of the best quantifiable parameters of postoperative recovery, after coronary artery bypass operations when compared with the standard full midline approach. METHODS: One hundred patients scheduled for elective coronary artery bypass grafting were randomized either for a full median sternotomy (standard sternotomy group, n = 50) or for a partial inferior sternotomy (ministernotomy group, n = 50). The following pulmonary features were assessed: vital capacity, forced expiratory volume, percentage of forced expiratory volume from vital capacity, total lung capacity, residual volume, maximum inspiratory pressure, and maximum expiratory pressure. Tests were performed preoperatively and on the fourth and tenth postoperative days. RESULTS: On the fourth postoperative day, both groups had a significant decrease in vital capacity (percentage of predicted values) when compared with preoperative values (preoperative vs fourth day: standard sternotomy group, 87.8% +/- 14.3% vs 42.1% +/- 10.2% [P <.0001]; ministernotomy group, 84.5% +/- 14.3% vs 41.5% +/- 11.8% [P <.0001]), with a significant tendency for recovery from the fourth to the tenth postoperative day (fourth vs tenth postoperative day: standard sternotomy group, 42.1% +/- 10.2% vs 66.3% +/- 12.3% [P =.001]; ministernotomy group, 41.5% +/- 11.8% vs 61.3% +/- 13.1 % [P =.002]). There were no differences in any test results between the groups on either the fourth or the tenth postoperative day. CONCLUSION: A less-invasive approach for coronary artery bypass operations with a partial inferior sternotomy does not improve early postoperative pulmonary function when compared with the conventional approach with a full sternotomy.

Coronary Artery Bypass↗

A study of lung function abnormalities in workers of cotton spinning shops.

Lung function was studied by forced expiratory spirograms and measurement of peak expiratory flow in fourteen young male subjects of the age 20 to 30 years. Seven of the subjects were cotton spinners in small shops in Paharganj market with the duration of work from 1 to 3 years. The other seven subjects served as controls. All the subjects were of the same socio-economic status and were North Indians. Forced vital capacity; forced expiratory volume in 1 sec; forced expiratory volume in 1 sec expressed as a percentage of forced vital capacity; forced expiratory flow between 80 and 70 per cent, between 55 and 45 per cent, between 30 and 20 per cent and between 15 and 5 per cent of the forced vital capacity were determined from forced expiratory spirograms. Peak expiratory flow and FEB-80-70% were significantly lower in cotton spinners suggesting involvement of larger airways.

Adult↗

Effect of helium and oxygen on airflow in a narrowed airway.

A mixture of 80% helium and 20% oxygen has physical properties that increase airflow and decrease resistance in the airway when used as a portion of inspired gas. This study was designed to demonstrate and quantify the effects of a helium-oxygen mixture in a normal airway and when airway resistance is increased. Thirty healthy volunteers were studied breathing room air and the helium-oxygen mixture through a normal airway and an airway that included a resistor. Pulmonary function tests, directed by a registered respiratory therapist, were performed on all subjects using a computerized spirometer. The functional vital capacity, one-second forced expiratory volume, half-second forced expiratory volume, and peak inspiratory flow rate were analyzed. There was a statistically significant increase in 1-second forced expiratory volume using a helium-oxygen mixture in a normal airway. All pulmonary function test scores statistically improved when volunteers inspired helium and oxygen through the restricted airway, demonstrating that helium and oxygen can increase airflow in the presence of an increased airway resistance. This substantiates a role for helium and oxygen in treating conditions associated with decreased airway size and increased airway resistance.

Adult↗

Reproducibility of pulmonary function tests under laboratory and field conditions.

The reproducibility of pulmonary function tests in the laboratory and in a mobile field survey vehicle has been studied. Groups of laboratory workers were studied at base and a random sample of 38 coalminers was examined in the mobile laboratory. The intra-subject variability of some newer tests of lung function, including closing volume and maximum flow at low lung volumes, has been compared with that of well-established tests, such as lung volumes and forced expiratory volume from two measurements made more than one day apart. Most measurements were slightly less reproducible in the study of coalminers than in the laboratory personnel. Conventional tests, such as forced expiratory volume in one second, lung volumes, single breath CO transfer factor, and exercise ventilation were very reproducible, the coefficients of variation (cov) being generally between 5% and 10%. The closing volume test, maximum expiratory flow at low lung volumes, and the single breath N2 index were less reproducible: cov between 15% and 39% in the miners. The forced expired time and volume of isoflow, measured only on laboratory workers, however, exhibited greater reproducibility than previously reported (cov = 10% and 15% respectively). It is suggested that, when assessing the repeatability of lung function tests, account should be taken of the circumstances in which the intra-subject variability was measured.

Adolescent↗

Changes in lung function during adolescence in athletes and non-athletes.

The purpose of this study was to evaluate the lung function in Indian athletes and non-athletes during adolescence. For this, lung functions in 40 boys (twenty athletes and twenty non-athletes) in the age range of 13 to 16 years, were evaluated over a period of two years at yearly intervals. The variables studied were Forced Vital Capacity (FVC), Forced Expiratory Volume in one second (FEV1), Expiratory Reserve Volume (ERV), Inspiratory Capacity (IC) and Maximum Voluntary Ventilation (MVV). Our results suggest that the development of the lung during adolescence under proper nutritional and health conditions is governed by the process of growth with no or negligible additional effects of physical activity. It is summarized that physical activity during growth may increase endurance in respiratory muscles. However, the findings of this study does not reject the possibility that lung size may increase by a strenuous and prolonged strength training regimen during adolescence.

Adolescent↗

Effect of wool dust on respiratory function.

A group of 252 workers (176 women and 76 men) employed in two wool mills was studied. The mean age of 36 years; mean exposure, 11 years. All women were nonsmokers, and 47 per cent of the men were regular smokers. Ventilatory function was measured by recording maximal expiratory flow-volume curves and forced expiratory volume in 1 sec on the first working day of the week (Monday) before and after the work shift. On maximal expiratory flow-volume curves the flow rates at 50 per cent of the control vital capacity were read. Workers exposed to wool dust for more than 10 years had a higher prevalence of chronic respiratory symptoms than did those with less than 10 years' exposure, but the difference was not significant. Significant reductions during the work shift were found in maximal expiratory flow rates at 50 per cent of the control vital capapity and 1-sec forced expiratory volume, the first test being considerably more sensitive. Workers exposed to wool dust for more than 10 years had signficantly lower than predicted pre-shift values for maximal expiratory flow rates at 50 per cent of the control vital capapcity. Inhalation of wool dust extract caused a significant decrease of maximal expiratory flow rates at 40 per cent of the control vital capacity on partial expiratory flow-volume curves during the 100 min after exposure. Comparison with the same concentration of cotton dust extract revealed a similar effect during the first 40 min after exposure but a significantly larger effect of the cotton dust extract after 40 min. The data suggest that preventive measures, especially medical supervision, are necessary in wool-processing mills to protect workers sensitive to dust.

Adult↗

Assessment of forced expiratory volume-time parameters in detecting histamine-induced bronchoconstriction in wheezy infants.

A new technique recently introduced allows the measurement of infant lung function from lung volumes raised by a pump prior to generation of forced expiratory flow-volume (FEFV) curves. Forced expiratory volume-time (FEV1) parameters rather than traditional flow parameters are used. The aim of this study was to assess the usefulness of FEV1 parameters in detecting airway responsiveness to histamine in recurrently wheezy infants. Ten infants (age 7-18 months) sedated with 80 mg/kg chloral hydrate underwent a histamine inhalation challenge. Throughout the challenge FEFV curves were generated from end-tidal inspiration. Raised FEFV curves, from a lung volume preset by 15 cmH2O inflation pressure, were gathered at baseline and after the final concentration of histamine. The mean fall from baseline was 47% in maximal flow at functional residual capacity (VmaxFRC) (P < 0.0005), 15.5% in FEV0.5 (P < 0.0001), 13.5% in FEV0.75 (P < 0.005), and 11.0% in FEV1.0 (P = 0.057), after the final concentration of histamine delivered. Tidal volume and inspiratory volume reached above FRC between pre- and posthistamine did not change. Mean oxygen saturation fell significantly from 97 to 93%. We conclude that FEV1 parameters adequately detect reduced lung function during histamine-induced bronchoconstriction and appear suitable for histamine challenge testing in infants.

Bronchoconstriction↗

Pulmonary function abnormalities in children with sickle cell disease.

BACKGROUND: Adults with sickle cell disease (SCD) have restrictive lung function abnormalities which are thought to result from repeated lung damage caused by episodes of pulmonary vaso-occlusion; such episodes start in childhood. A study was therefore undertaken to determine whether children with SCD have restrictive lung function abnormalities and whether the severity of such abnormalities increases with age. METHODS: Sixty four children with SCD aged 5-16 years and 64 ethnic matched controls were recruited. Weight and sitting and standing height were measured, and lung function was assessed by measurement of lung volumes and forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC), and peak expiratory flow (PEF) before and after bronchodilator. RESULTS: Compared with the control subjects, the children with SCD had lower mean (SD) sitting height (69 (6.3) cm v 73 (7.7) cm; p=0.004), sitting:standing height ratio (0.50 (0.02) v 0.51 (0.01); p<0.0001), weight (33 (10.9) kg v 41 (14.9) kg; p=0.001), functional residual capacity measured by a helium gas dilution technique (1.2 (0.3) l v 1.3 (0.4) l; p=0.04), FEV1 (1.5 (0.5) l v 1.9 (0.7) l; p=0.0008), FVC (1.7 (0.6) l v 2.1 (0.8) l; p=0.001), and PEF (3.9 (1.3) l/s v 4.8 (1.5) l/s; p=0.0004). The effect of age on lung function differed significantly between the children with SCD and the controls for total lung capacity and vital capacity measured by plethysmography and functional residual capacity measured by helium gas dilution. CONCLUSION: Lung function differs significantly in children with SCD compared with ethnic matched controls of a similar age. Our results suggest that restrictive abnormalities may become more prominent with increasing age.

Adolescent↗