Predictive nomograms for forced expiratory volume, forced vital capacity, and peak expiratory flow rate, in Chinese adults and children

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.     

Sources of variation in forced expiratory volume in one second and forced vital capacity.

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.     

Ratio between forced expiratory flow between 25% and 75% of vital capacity and FVC is a determinant of airway reactivity and sensitivity to methacholine

STUDY OBJECTIVE: The ratio between forced expiratory flow between 25% and 75% of vital capacity (FEF(25-75)) and FVC is thought to reflect dysanapsis between airway size and lung size. A low FEF(25-75)/FVC ratio is associated with airway responsiveness to methacholine in middle-aged and older men. The current study was designed to assess this relationship in both male and female subjects over a broader range of ages. STUDY DESIGN: Data analysis of consecutive subjects who had a >or= 20% reduction in FEV(1) after 相似文献   

Comparison between peak expiratory flow rate and forced expiratory volume in one second in the evaluation of children suspected to have asthma

This study was conducted to evaluate whether forced expiratory volume in 1 second (FEV1) for the diagnosis of bronchial reactivity by means of the free-running exercise test and bronchodilator inhalation, could be appropriately replaced by simple measurements of peak expiratory flow rate (PEFR) in children.We studied 108 referred symptomatic children (due to chronic cough or wheezing) suspected to have asthma aged 5-14y. Forced breathing spirometry and the "Mini-Wright peak flow meter" tests were recorded before and fifteen minutes after the challenge with free- running exercise or bronchodilator (Salbutamol) inhalation, regarding the baseline FEV1 value (FEV1> 80% considered as normal).There was a high correlation between PEFR and FEV1 (in absolute value and percent predicted) measured before and after bronchodilator inhalation test (r = 0.48, P = 0.05) in comparison to the values referred to free- running exercise test (r = 0.26, P = 0.01)."forced breathing spirometry" and "Mini-Wright peak flow" cannot be used interchangeably for diagnosing asthma, and PEFR measurement should remain a procedure for monitoring and following up the patients.     

The significance of the difference between slow inspiratory and forced expiratory vital capacity

In 112 healthy subjects and 1, 767 patients examined for subjective complaints or assessment of pneumoconiosis, the routine examination of clinical status, chest X-ray and lung function was completed by measurement of forced expiratory vital capacity (FVC) and calculation of the difference between inspiratory and forced expiratory vital capacity (dVC). The results show that only in healthy subjects the difference between slow inspiratory vital capacity (VC) and FVC may be neglected, but in patients both values might differ by more than 1000 ml and cannot replace each other. Airway resistance as measured by body plethysmography cannot be reliably calculated from various spirometric values.     

Should forced expiratory volume in six seconds replace forced vital capacity to detect 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.     

Advantages of late expiratory relaxation during maximal forced expiratory maneuver

A modification of the maneuver for the maximal expiratory flow volume (MEFV) curve was described recently to improve the rate of achieving the acceptability criteria of the American Thoracic Society. The maneuver allows the subject to relax in the later part of expiration. The present study was carried out to determine if the modified spirometry technique offered any advantages over the standard FVC maneuver in asthma patients with a wide range of airways obstruction. MEFV curves were obtained in seventy-two subjects with standard and modified procedures in a randomized, crossover design. The patients were divided into four groups depending on the degree of airways obstruction-normal spirometry, mild, moderate and severe airways obstruction. The spirometric parameters (FVC, FEV1, FEV/FVC ratio, FET, PEFR and F25-75) were compared in each group. The modified technique gave a higher FVC measurement especially in patients with moderate and severe airways obstruction along with increased FET. PEFR and FEV1 were not different between the techniques. FEV1/FVC ratio was significantly decreased in patients with moderate and severe airways obstruction. Both the techniques gave equally acceptable and reproducible results with similar variability for FEV1 and FVC. It was concluded that the modification of the standard FVC maneuver by allowing the subject to relax in the later part of expiration is advantageous as it yields a lower FEV1/FVC ratio without affecting the FEV1, has the same within-session variability and is less strenuous.     

Evaluation of a hand-held spirometer, the Respiradyne, for the measurement of forced expiratory volume in the first second (FEV1), forced vital capacity (FVC) and peak expiratory flow rate (PEFR)

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.     

COPD和哮喘患者支气管舒张实验用力肺活量和呼气容积的变化

目的 探讨COPD和哮喘患者支气管舒张实验用力肺活量和呼气容积变化.方法 随机选取COPD急性加重期78例和哮喘急性发作期64例,采用支气管舒张实验比较COPD和哮喘患者实验前后用力肺活量(FVC)、一秒用力呼气容积(FEV1)的增加量和增加率.结果 支气管舒张实验后,COPD患者的用力肺活量(FVC)的增加量191 ml,较舒张前增加12.93%,而一秒用力呼气容积(FEV1)的增加量63 ml,较舒张前增加10.01%;哮喘患者的用力肺活量(FVC)的增加量363 ml,较舒张前增加15.34%,而一秒用力呼气容积(FEV1)的增加量289 ml,较舒张前增加23.57%.结论 COPD患者支气管舒张试验后用力肺活量的增加幅度大于呼气容积的增加幅度,而哮喘患者正好相反,因此用力肺活量可鉴别COPD和哮喘患者病情的客观指标.