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A survey of three indices of ventilatory capacity, forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC) and peak expiratory flow rate (PEFR), was undertaken on 3490 Chinese inhabitants of Hong Kong. Nomograms have been constructed for the prediction of these three indices for subjects between the ages of 5 and 75 years.
Although the use of the posterior mediastinum and the stomach as a reconstruction option after esophagectomy has large acceptance all over the world, there are concerns about the potential respiratory impairment it could cause. We prospectively studied 35 patients regarding the forced expiratory volume and vital capacity. The patients were studied preoperatively and between the 45th and 60th postoperative days. The value of both parameters decreased, although they were still within normal clinical ranges. We concluded that this type of reconstruction does not harm the patients regarding the respiratory flow rates.
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OBJECTIVES: To compare the acceptability, reproducibility, and sensitivity of spirometric outcome measures of airway caliber during challenge testing in children. DESIGN: FEV(1), forced expiratory volume in 0.75 s, forced expiratory volume in 0.5 s, and peak expiratory flow (PEF) were recorded during stepwise dosimetric histamine challenge tests. The responses were compared, and the reproducibility at baseline and from duplicate measurements at each challenge step was determined. PATIENTS: One hundred five children with newly diagnosed asthma, aged 5 to 10 years. RESULTS: Compared to PEF, FEV(1) showed better baseline reproducibility (p = 0.002) and higher sensitivity (p < 0.0001) during challenge testing, determined as the change normalized to the baseline variation, while the forced expiratory volumes were not significantly different in these respects. During challenge testing in subjects with acceptable flow-volume tracings, paired recordings of FEV(1) agreed within 0.1 L in 85% and within 0.2 L in 93% of measurements. During challenge testing, the reproducibility of FEV(1) measurements was not better than that of the other indexes. Failure to exhale long enough precluded the use of FEV(1) in 16 of the children, particularly the youngest children. CONCLUSIONS: The results demonstrated that the recently published guidelines for FEV(1) measurements during challenge tests can be applied to children. During challenge tests in asthmatic children, the advantage of the shorter fractions of forced expiratory volume was that they were more often acceptably recorded than FEV(1), while they showed as good reproducibility and were also equally sensitive in assessing changes in airway obstruction.
It has been suggested that forced expiratory volume in six seconds (FEV(6)) should be substituted for forced vital capacity (FVC) to measure fractions of timed expired volume for airflow obstruction detection. The present authors hypothesised that this recommendation might be questionable because flow after 6 s of forced expiration from more diseased lung units with the longest time constants was most meaningful and should not be ignored. Furthermore, previous studies comparing FEV(6) and FVC included few subjects with mild or no disease. The present study used spirometric data from the USA Third National Health and Nutrition Evaluation Survey with prior published ethnicity- and sex-specific equations for FEV(1)/FEV(6), FEV(1)/FVC and FEV(3)/FVC, and new equations for FEV(3)/FEV(6), all derived from approximately 4,000 adult never-smokers aged 20-80 yrs. At 95% confidence intervals, 21.3% of 3,515 smokers and 41.3% of smokers aged >51 yrs had airway obstruction; when comparing FEV(1)/FEV(6) with FEV(1)/FVC, 13.5% were concurrently abnormal, 1.5% were false positives and 4.1% were false negatives; and when comparing FEV(3)/FEV(6) with FEV(3)/FVC, 11.6% were concurrently abnormal, 3.3% were false positives and 5.7% were false negatives. Substituting forced expiratory volume in six seconds for forced vital capacity to determine the fractional rates of exhaled volumes reduces the sensitivity of spirometry to detect airflow obstruction, especially in older individuals and those with lesser obstruction.
Tracheal area at different lung volumes was measured using acoustic reflection technique, flow-volume curves, and lung volumes by body plethysmography in 24 healthy adults (14 men, 10 women) in order to study the relationship between tracheal area and lung volume, and between tracheal area and maximal expiratory flow rates. Each individual tracheal area was greatest at TLC and lowest at RV; this lung volume dependence was significantly greater in men than in women. When tracheal areas versus absolute lung volumes were plotted for the entire group and the linear regression analysis on the data was performed, no significant correlation between lung volume and tracheal area in men was found, but a highly significant correlation was found in women. Using the analysis proposed by Mead (Am Rev Respir Dis 1980; 121:339-42) in his assessment of dysanapsis, the ratio of tracheal area/lung volume versus lung volume was plotted and the slope was found to be negative (and close to -1) in men and positive in women. Therefore it was concluded that the relationship between tracheal area and lung volume is consistent with the hypothesis that in men and women lung parenchyma grows independently of the airways; furthermore, in women the airways grow faster than the lung parenchyma. In addition, in women there was good correlation between tracheal area and FEV1, as well as maximal expiratory flow rates at 50 and 25% of VC. For men, these correlations were less consistent and depended on the lung volume at which tracheal area was measured.
A hand-held spirometer, the Respiradyne (R), was evaluated for the measurement of forced expiratory volume in the first second (FEV1), forced vital capacity (FVC) and peak expiratory flow rate (PEFR) by comparing it with a Vitalograph spirometer (V) and a Wright's peak flow meter (W) in 70 subjects (normals and patients). The results showed close agreement for FEV1; r = 0.99, R = 0.961V + 0.03 X 10(-5) and FVC; r = 0.99, R = 1.003V-0.044. Results for PEFR using the Respiradyne were generally higher than with the peak flow meter; r = 0.98, R = 1.151W-17.576. The Respiradyne is portable and simple to operate and may be suited to use in a variety of non-laboratory situations.
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Forced expiratory volume in one second (FEV1) and forced vital capacity (FVC) of 243 healthy male Japanese workers were measured on as annual basis over seven years, and their longitudinal decline was compared with the age coefficient of cross-sectional prediction equations reported previously for Japanese adults. In this study, a man, assumed to be 1.65 meter tall, was expected to have a respective 22 ml and 11 ml decline annually in FEV1 and FVC. Age-related differences of those indices obtained from cross-sectional prediction equations, however, ranged from 22 ml to 31 ml a year in FEV1 and from 16 ml to 25 ml in FVC for men of the same height. Furthermore, in those equations, age was simply employed as a first-order explanatory variable for ages ranging from the later teens to over sixties, although age-related acceleration of FVC decline is suggested in this study. These results indicate that evaluations of measurements relating to time-series pulmonary functions on cross-sectional prediction equations might be biased. This is probably due to the influence of age-cohort. It seems necessary to build up the reference standards for longitudinal pulmonary function change for an appropriate evaluation of time-series data of FVC and EFV1.
The mean annualized changes in height (delta height), in forced expiratory volume in one second (delta FEV1), and in forced vital capacity (delta FVC), measured at a 5-yr interval, were determined by year of age for 1,458 residents 7 to 59 yr of age in 2 communities in Los Angeles. The rate of change in delta height, delta FEV1, and delta FVC increased each year until early puberty and then decreased thereafter. The age at which the delta FEV1 and delta FVC reversed from an increasing to a decreasing rate was older in males (13 yr) than in females (11 yr) and lagged about 1 yr behind the age at which rate of delta height reversed. The rate of delta FEV1 and delta FVC sharply declined thereafter until the early 20s, at which age the rate of change leveled off to a constant value. The age at which the delta FEV1 and delta FVC reversed from positive to negative ranged from 21 to 23+ yr, but was probably of less importance physiologically than the age at which the rate of change in delta FEV1 and delta FVC leveled off. The results suggest that growth factors are the major determinants for changes in delta FEV1 and delta FVC until the late teens. From the until the mid-20s, both growth factors and physiologic deterioration may affect delta FEV1 and delta FVC. Thereafter, the primary determinant of delta FEV1 and delta FVC appears to be a gradual but steady decline in physiologic status.
An inexpensive pocket-sized instrument--the turbine spirometer--has been developed that measures and gives a direct digital display of the forced expiratory volume in one second and forced vital capacity. The instrument is as accurate as and considerably cheaper than spirometers in general use. Condensation does not affect the calibration. The turbine spirometer will enable spirometry to be easily monitored in hospital wards and general practice and by patients at home.
Published prediction equations for lung function differ considerably, but the components of population variation responsible for the differences are unknown. Data were analysed for 6,323 never-smoking adults who did not report wheeze or asthma, from 42 centres participating in the European Community Respiratory Health Survey. Means and components of variance were estimated for males and females aged 20-24 yrs, and the relationships with age and height were examined in those aged 25-44 yrs. Mean lung function for those aged 20-24 yrs differed between centres, but variation could not be wholly attributed to differences in population or equipment. The maximum difference in means by equipment type was 101 mL for FVC in males. Equipment differences were not statistically significant adjusted for country, but differences in mean forced expiratory volume in one second and forced vital capacity by country, adjusted for instrument, were statistically significant in males. Differences between centres in relation to age and height had less influence on predicted values. In conclusion, there are unexplained differences in lung function between ethnically similar nonsmoking symptom-free populations. Neither national reference curves nor those based on the same ethnic group can be guaranteed to give accurate norms of lung health.
OBJECTIVE: To assess factors that influence pulmonary function, because respiratory system dysfunction is common in chronic spinal cord injury (SCI). DESIGN: Cross-sectional cohort study. SETTING: Veterans Affairs Boston SCI service and the community. PARTICIPANTS: Between 1994 and 2003, 339 white men with chronic SCI completed a respiratory questionnaire and underwent spirometry. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURES: Forced expiratory volume in 1 second (FEV(1)), forced vital capacity (FVC), and FEV(1)/FVC. RESULTS: Adjusting for SCI level and completeness, FEV(1) (-21.0 mL/y; 95% confidence interval [CI], -26.3 to -15.7 mL/y) and FVC (-17.2 mL/y; 95% CI, -23.7 to -10.8 mL/y) declined with age. Lifetime cigarette use was also associated with a decrease in FEV(1) (-3.8 mL/pack-year; 95% CI, -6.5 to -1.1 mL/pack-year), and persistent wheeze and elevated body mass index were associated with a lower FEV(1)/FVC. A greater maximal inspiratory pressure (MIP) was associated with a greater FEV(1) and FVC. FEV(1) significantly decreased with injury duration (-6.1 mL/y; 95% CI, -11.7 to -0.6 mL/y), with the greatest decrement in the most neurologically impaired. The most neurologically impaired also had a greater FEV(1)/FVC, and their FEV(1) and FVC were less affected by age and smoking. CONCLUSIONS: Smoking, persistent wheeze, obesity, and MIP, in addition to SCI level and completeness, were significant determinants of pulmonary function. In SCI, FEV(1), FVC, and FEV(1)/FVC may be less sensitive to factors associated with change in airway size and not reliably detect the severity of airflow obstruction.
As part of a longitudinal study of the respiratory health effects of air pollution, we measured the lung function of 2,454 white adults 25 to 74 yr of age who had never smoked and who reported no respiratory symptoms. These measurements were analyzed to develop a simple model for the cross-sectional dependence of pulmonary function on height, sex, and age. Both forced expiratory volume in one second (FEV1) and forced vital capacity (FVC) can be effectively standardized for body size by dividing each pulmonary function measurement by the square of the standing height (HT2). The age-specific distribution of these standardized measurements is approximately Gaussian, with variance that is independent of age. Plots of FEV1/HT2 and FVC/HT2 against age showed a nonlinear relationship consistent with an increase in the rate of pulmonary function loss with age. On the basis of these graphic analyses, both pulmonary function measurements were fitted to a four-parameter normative model including sex and linear and quadratic terms in age as dependent variables. This model gave predictions that were very close to those from more complicated models currently in use. Predicted percentile levels were calculated for each sex and age, and shown to describe the observations well. The estimated annual change in height-standardized lung function based on the cross-sectional model was compared with the observed change between the first and second examinations of these adults 3 yr later. The observed changes were close to predicted values, except for subjects younger than 35 yr of age at their first examination. The observed change was larger for men than for women. Such simple longitudinal comparisons are subject to selection bias. In this study, subjects in the lowest quartile of FEV1/HT2 for their age and sex at the first examination had a lower probability of providing a lung function measurement 3 yr later.
We examined the effects from subjects, technicians and spirometers on within-session variability in successful recordings of forced expiratory volume in 1 second (FEV1) and forced vital capacity (FVC) in 4989 asymptomatic never-smoking men. All eligible men aged 30-46 years living in western Norway (n = 45,380) were invited to a cross-sectional community survey. Information on respiratory symptoms, smoking habits and occupational exposures was obtained from a self-administered questionnaire. Three successful FEV1 and FVC recordings were obtained in 26,368 attendants using three dry-wedge bellow spirometers operated by 10 different technicians. Within-subject standard deviation (SD) from three recordings of FEV1 and FVC was on average 102 and 106 ml, respectively, and increased with height (14 and 17 ml, respectively, per 10 cm) and body mass index (BMI) (11 and 14 ml, respectively, per 5 kg m-2). Between-subject SD of the mean of three FEV1 and FVC recordings was 591 and 754 ml, respectively, and increased in groups of increasing height (43 and 40 ml, respectively, per 10 cm). Small, but significant, differences were observed between technicians in within-subject SD and in levels of FEV1 and FVC. Homogeneity of between-subject variability, necessary for linear regression analysis, was obtained using FEV1 and FVC divided by height squared. In conclusion, within-subject variability in three successful spirometric recordings was small, but dependent on height and BMI of the subjects as well as technician performance. The observed heterogeneity in between-subject variation in FEV1 and FVC levels disappeared when each variable was divided by height squared. Novel multiple linear regression equations for FEV1/height2 and FVC/height2 were developed to be used in evaluating the effects from occupational airborne exposures in Nordic men aged 30-46 years.