1-sec Forced Expiratory Volume Research Articles

Quantitative relationships between cigarette smoking and ventilatory function.

In this study of a general population sample, highly significant quantitative relationships were noted between pack-years of smoking and functional impairment. Subjects with chronic productive cough showed steeper declines in the forced expired volume in 1 sec and forced expiratory flow after exhalation of 75 per cent of the forced vital capacity (Vmax 25), but a definite inverse relationship between ventilatory function and pack-years was demonstrated even among subjects who denied any cough or sputum production. Current smoking showed no relationship to 1-sec forced expiratory volume or Vmax 25 when total pack-years were taken into account. Age appeared to be an important independent determinant of per cent predicted values only in regard to the Vmax 25 in symptomatic nonsmoking women. A history of childhood respiratory trouble was associated with a lower ventilatory function regardless of smoking habits, and for this reason such subjects have been deleted from detailed analyses of dose-effect relationships. Allergy skin test reactivity in young to middle-aged adults showed a significant additive effect to pack-years as a determinant of forced expiratory flow toward the end of the forced vital capacity, but the effect was noted only among present smokers.

Five- to seven-year course of pulmonary function in cystic fibrosis.

The pulmonary function records of 132 patients with cystic fibrosis followed for 5 to 7 years were reviewed. Changes in forced vital capacity, 1-sec forced expiratory volume, mean forced expiratory flow during the middle half of the forced vital capacity, and 1-sec forced expiratory volume as a percentage of forced vital capacity were examined. There was considerable variation in the rates of change, but the general pattern was consistent with a theory of exponential decline, mean forced expiratory flow during the middle half of the forced vital capacity showing the earliest and most dramatic changes. The pulmonary function of 33 patients (25 per cent) remained stable or improved throughout follow-up, possibly reflecting mild forms of lung disease or the efficacy of therapy. Twenty of these patients (15 per cent) maintained completely normal pulmonary function. The rate of decline in pulmonary function values, with progress of the disease, was steeper in the female patients.

Respiratory effects of live influenza virus vaccine: healthy older subjects and patients with chronic respiratory disease.

Twenty-one healthy, middle-aged volunteers and 8 patients with chronic lung disease were given live, attenuated influenza virus vaccine by nasal spray. Forced vital capacity, 1-sec forced expiratory volume, ratio of 1-sec forced expiratory volume to forced vital capacity, residual volume, ratio of airway conductance to lung volume, maximal expiratory flows after exhalation of 50 and of 75 per cent of the forced vital capacity, closing volume, slope of Phase III, volume of isoflow, single-breath diffusing capacity for CO, and arterial blood gases were measured before and 3, 7, 10, and 21 days after exposure. Vaccination was well tolerated by the healthy volunteers without change in pulmonary function. In contrast, the patients tended to develop increased respiratory symptoms and had a slight decrease in mean forced expiratory volume in 1 sec 3 weeks after vaccination.

Lung function among black and white children.

Racial differences in ventilatory lung function were evaluated in a community study of 393 children (158 blacks, 235 whites). Mean forced vital capacity was 18 per cent larger in nonsmoking white males than in nonsmoking black males, and 11 per cent larger in nonsmoking white females than in nonsmoking black females. Similar differences were observed for the 1-sec forced expiratory volume and for the maximal expiratory flow at 50 per cent of the vital capacity. However, when adjusted for lung size (on the basis of forced vital capacity), 1-sec forced expiratory volume and maximal expiratory flow at 50 per cent of the forced vital capacity were larger in the black children compared to the white children. Lung function prediction equations based on race, sex, age, height and weight are presented for healthy nonsmoking children; these allow for an evaluation of normal lung function in both black and white children.

Follow-up evaluation of a prevalence study for chronic bronchitis and chronic airway obstruction.

Follow-up of the prevalence study of respiratory symptoms and chronic airway obstruction was performed after a 6- to 7-year interval. One hundred fifteen of 117 subjects (98%) originally labeled "abnormal" (chronic bronchitis or asthma by history, or ratio of 1-sec forced expiratory volume to forced vital capacity less than 60 per cent), and 111 of a random sample of 116 subjects (96%) originally labeled "normal" were traced. Nineteen patients were dead, 14 "abnormal" subjects, and 5 "normal" subjects (P less than 0.01). Eighty-eight of the originally labeled "abnormal" subjects and 91 of the random "normal" sample could be retested by spirometry. Subjects with lower initial ratios of 1-sec forced expiratory volume to forced vital capacity tended to lose more 1-sec forced expiratory volume and forced vital capacity. Early identification of respiratory symptoms and spirometric abnormalities may identify persons at increased risk of death who could benefit from appropriate therapy.

Lung function changes in smokers with normal conventional spirometry.

The comparative ability to detect early abnormalities in smokers by commonly used lung function tests was studied. Sixty-five healthy male nonsmokers served as a reference group and provided standards for 1-sec forced expiratory volume, vital capacity, end-tidal spirometry, spirometric forced mid-and end-expiratory flows, single-breath diffusing capacity, static lung volumes (helium method), and single-breath N2 closing volume measurements, In the present series of 80 male smokers, the measurements of forced mid-expiratory flow and forced end-expiratory flow did not improve the ability of the more conventional indices, 1-sec forced expiratory volume and the ratio of 1-sec forced expiratory volume to vital capacity, to detect obstructive lung disease. In 71 smokers with normal 1-sec forced expiratory volume and ratio of 1-sec forced expiratory volume to vital capacity, the end-tidal spirometry, diffusing capacity, and residual volume indices revealed 14,20, and 21 per cent of abnormalities. respectively. The single-breath N2 closing volume test (Phase IV/vital capacity and slope of Phase III) detected the greatest number of subtle changes in lung function; this was abnormal in 32 per cent of smokers with normal conventional spirometry. In young or light smokers, Phase IV/vital capacity was more frequently increased than the slope of Phase III; an incerse trend was observed in older or heavier smokers. The single-breath N2 closing volume test also provided the greatest number of abnormal results when other indices were impaired in the same subjects.

Incidence of exercise-induced asthma in children

The incidence of exercise-induced asthma (EIA) was studied in 134 asthmatic and 102 nonasthmatic atopic children and compared to that in 56 nonatopic children. Pulmonary function tests measuring forced vital capacity (FVC) and 1-sec forced expiratory volume (FEV 1) were performed on each child prior to and serially for 20 min following free running exercise. The incidences of EIA among the asthmatic and atopic nonasthmatic children were 63% and 41%, respectively. This phenomenon is widespread among allergic children and cannot be accurately predicted from the history. A simple and easily performed outpatient procedure is described for the diagnosis of EIA.

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.

The response of asthmatic subjects to isoproterenol inhaled at differing lung volumes.

Asthmatics are usually instructed to use pressurized bronchodilator aerosols by delivering a bolus of drug at the beginning of a full inspiration. Because airways are better dilated near total lung capacity, the delivery of the drug near the end of a full breath might allow better penetration of particles into the lung and greater bronchodilatation. To test this hypothesis, 13 asthmatic subjects inhaled 400 mug of isoproterenol at 20 per cent (low) and at 80 per cent (high) vital capacity. The studies were done on 2 separate days when the severity of asthma was the same. Forced vital capacity, 1-sec forced expiratory volume, specific airway conductance and maximal flow at 50 per cent of viral capacity were measured at frequent intervals after drug administration. Ten min after drug delivery, there was a significantly greater (P less than 0.05) improvement in 1-sec forced expiratory volume after the drug was inhaled at the high lung volume compared to the response after delivery at the low lung volume. The differences in forced vital capacity, specific conductance, and maximal flow at 50 per cent of vital capacity were not significant. We concluded that inhaling a bronchodilator drug at the end of a full inspiration causes relatively greater bronchodilatation than inhaling the same dose at the beginning of inspiration.

Effect of modification of the smoking habit on lung function.

The effect of smoking cessation or modification on lung function was determined during a 48-week period. In a large number of the cigarette smokers, a disturbance of lung function was not revealed by conventional tests, such as the 1-sec forced expiratory volume; however, an abnormality was often demonstrable in tests that may reflect alterations in small airways, such as closing volume and Phase III of the single-breath expired N2 curve. There was no relation between the degree of abnormality of lung function and the presence of respiratory symptoms, but there appeared to be a relationship to lifetime smoking history, the heaviest smokers having the poorest function. Cessation, or more than 25 per cent decrease in the number of cigarettes smoked, was attened by improvement in the slope of Phase III of the N2 washout curve, closing volume, and closing capacity, as well as forced vital capacity, 1-sec forced expiratory volume, and peak flow. Resumption of smoking after cessation was attended by a deterioration in the slope of Phase III and closing capacity. The data suggest that the functional abnormalities in smokers are related to smoking and are at least partially reversible by cessation or significant modification of the smoking habit.

Pulmonary effects of chronic exposure to airborne cadmium.

Workers chronically exposed to high concentrations of airborne cadmium showed a significantly decreased forced vital capacity relative to a low-exposure group and had Po2 values in the normal range, but at the extreme low end. They had no significant decrease in 1-sec forced expiratory volume or maximal mid-expiratory flow. Chest roentgenograms showed mild or moderate interstitial fibrosis in 29 per cent of the group exposed to cadmium. Collectively, these results suggest a mild fibrotic reaction associated with exposure to cadmium. A dose-response association was observed between forced vital capacity, expressed as per cent predicted, and both average urinary cadmium concentration (P less than 0.003; r=-0.53) and maximal urinary cadmium concentration (P less than 0.005; r=-0.51). Further, a dose-response relationship was found between the forced vital capacity and months of work in cadmium fume areas, but not for months of exposure to cadmium sulfate aerosol.

Respiratory response to tobacco dust exposure.

Results of a study of the respiratory responses of 318 nonsmoking female workers to long-term tobacco dust exposure are reported. The mean total tobacco dust concentrations ranged from 0.9 to 27.5 mg per m3; the respirable fraction, from 0.3 to 3.6 mg per m3. The mean length of exposure to tobacco dust was 14.9 years; 24 per cent of the workers had been exposed to tobacco dust for 20 years or more. Comparatively low prevalences of chronic respiratory symptoms were found, and only the prevalences of chest tightness and wheezing were significantly higher among workers exposed to tobacco dust than those of the control group (P less than 0.01). Calculating the expected 1-sec forced expiratory volume and forced vital capacity values by means of multiple linear regression equations, developed on the basis of data obtained in the 210 control subjects, revealed no significant differences between the measured and expected ventilatory capacity values among any of the groups of the workers observed. In contrast to negative findings with regard to chronic respiratory effects, significant acute decreases in ventilatory capacity during the work shift were recorded. No dose-response relationship was found between the level of exposure and the acute decreases in ventilatory capacity.

Relationship of constitutional factors and cigarette smoking to decrease in 1-second forced expiratory volume.

A 5-year prospective survey of 34 subjects with mild chronic bronchitis revealed marked individual variation in the annual rate of decrease in the forced expiratory volume in 1 sec. The mean annual decrease in the 1-sec forced expiratory volume was 0.046 +/- 0.057 liter. Although the annual decrease in the 1-sec forced expiratory volume was greater among smokers (0.056 +/- 0.061 liter per year) than non- and ex-smokers (0.016 +/- 0.021 liter per year; P less than 0.005), differences in tobacco consumption did not account for the individual variation. This variation was related, instead, to 3 phenomena believed to indicate the presence of host susceptibility to chronic bronchitis. These phenomena were bronchial reactivity to methacholine, ventilatory responsiveness to isoproterenol, and sputum eosinophilia. The correlation between the rate of decrease in 1-sec forced expiratory volume and the degree of methacholine reactivity was 0.76 (P less than 0.001); the correlation between the decrease in 1-sec forced expiratory volume and ventilatory responsoveness to isoproterenol was 0.45 (P less than 0.01). Deterioration of 1-sec forced expiratory volume was appreciably greater among those with sputum eosinophilia (0.062 +/- 0.06 liter per year) than among thse without eosinophilia (0.017 +/- 0.033 liter per year P less than 0.01). The progression of abnormality appeared to depend on an interaction between cigarette smoking and individual susceptibility. Even minimal tobacco consumption led to serious ventilatory deterioration when methacholine reactivity was high, whereas heavy smoking produced little effect on the decrease in 1-sec forced expiratory volume when methacholine reactivity was slight.

The effect of acute, intensive cigarette smoking on maximal expiratory flows and the single-breath nitrogen washout trace.

The effect of acute, intensive cigarette smoking on forced vital capacity and the single-breath expired N2 trace was studied in 82 smokers. There were significant decreases in the "effort-dependent" tests, such as peak flow and 1-sec forced expiratory volume, but no change in the more "effort-independent" tests, such as maximal mid-expiratory flow and maximal expiratory flow at 25 per cent of the vital capacity. Closing volume was unchanged in absolute terms and as a percentage of vital capacity. Closing capacity was unchanged in absolute terms and as a percentage of total lung capacity, but there was a significant increase in the slope of Phase III of the N2 washout curve after the acute smoking session. The tests of function that changed significantly after acute, intensive smoking were the ones that improved in 52 subjects who modified their smoking habits. The data suggest that acute, intensive cigarette smoking may be associated with an increase in resistance to air flow in the larger airways or a reduction in effort, and with increased nonuniformity of intraregional distribution of ventilation.

Response of asthmatics to methacholine and suggestion.

Effects of diluent, methacholine, and suggestion on pulmonary function were studied in 9 asthmatic subjects. On day 1, flavored diluent was given as a control preparation. On day 2, increasing concentrations of similarly flavored methacholine were administered. On day 3, the effect of flavored diluent plus suggestion was studied. Although all variables were affected, the dose-response relationships for methacholine were most pronounced for specific airway conductance and airway resistance, in contrast to maximal mid-expiratory flow, forced expiratory volume in 1 sec, and forced vital capacity. Suggestion toward bronchoconstriction significantly affected only the plethysmographic parameters, specific airway conductance, and airway resistance, and not the spirometric variables. Both airway resistance and 1-sec forced expiratory volume showed slight, but significant, changes as a result of bronchodilator suggestion, which was used to overcome the suggestion toward bronchoconstriction. Because suggestion had a greater effect on large airways than peripheral airways, a role for the vagus is implied. Thus, any protocol using body plethysmography must consider a possible effect of suggestion on results.

Volume-controlled Lung Lavage in a Woman with Cystic Fibrosis

A 22-year-old woman with cystic fibrosis was treated by volume-controlled lavage of each of her lungs on two occasions. Following the first lavages, the patient's vital capacity increased by 1.03 liters and her 1-sec forced expiratory volume increased by 0.70 liters/second. Similar improvements, although less pronounced, were noted after both lungs has been lavaged a second time. It is concluded that volume-controlled lung lavage can be of benefit as an adjunct in the treatment of patients with cystic fibrosis.

Influence of tuberculin on ventilatory parameters in patients with chronic bronchitis.

The influence of tuberculin administered in aerosol on the ventilatory parameters in patients suffering from chronic bronchitis has been studied. The diameter of the tuberculin skin reaction 1 day after inhalation of tuberculin was found to be related to a decrease in maximal 1-sec forced expiratory volume and maximal midexpiratory flow-rate. Significant decrease in the parameters of dynamic pulmonary ventilation occurred only in a certain proportion (24.6%) of tuberculin-positive patients suffering from chronic bronchitis of the obstructive type.