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At least 91 records · Page 5Linked to original sources
PubMed1998

The value of forced expiratory volume in 1 s in screening subjects with stable COPD for PaO2 < 7.3 kPa qualifying for long-term oxygen therapy.

Guidelines on the management of chronic obstructive pulmonary disease (COPD) issued by the European Respiratory Society (ERS), British Thoracic Society (BTS), American Thoracic Society (ATS), and Department of Health for England and Wales (DoH) suggest differing values of forced expiratory volume in 1 s (FEV1) below which arterial blood gas analysis should be performed to determine the presence of severe hypoxaemia and possible long-term oxygen therapy (LTOT) requirement. This study aimed to determine the value of FEV1 at these different levels in screening for LTOT requirement defined as PaO2 < 7.3 kPa in subjects with stable COPD. Comparative measures were taken against other lung function tests of volume and diffusing capacity. A retrospective analysis of paired lung function and arterial oxygen measurements in 491 subjects was made. The positive and negative predictive values, sensitivity and specificity of FEV1 < 70% predicted (ERS), FEV1 < 50% predicted (ATS), FEV1 < 40% predicted (BTS) and FEV1 < 1.51 (DoH) were determined for fulfilling LTOT criteria (PaO2 < 7.3 kPa). The correlation between lung function variables and PaO2 was established. Logistic regression analysis was used to classify subjects with PaO2 < 7.3 kPa and PaO2 > or = 7.3 kPa. Using FEV1 to screen for LTOT requirement produced a high negative predictive value at all four suggested limits (FEV1 < 70% 100%, FEV1 < 50% 96%, FEV1 < 40% 95%, FEV1 < 1.51 97%). However, the positive predictive values were low (FEV1 < 70% 13%, FEV1 < 50% 16%, FEV1 < 40% 19%, FEV1 < 1.51 15%) as were sensitivities. No single lung function variable was a strong determinant of PaO2. FEV1 % pred (r = 0.40), FVC % pred (r = 0.34) and TLCO % pred (r = 0.27) had the strongest relationships. Logistic regression also placed FEV1 % pred and TLCO % pred as the best predictors of PaO2 < 7.3 kPa. We conclude no lung function variable correlates well with PaO2 in subjects with stable COPD. The best predictor of PaO2 < 7.3 kPa was FEV1 % pred. Whilst a low FEV1 is a poor predictor of LTOT requirement in an individual, PaO2 < 7.3 kPa is only found in subjects with a low FEV1. A high FEV1 may be used to exclude subjects from further investigation for LTOT and prevent unnecessary arterial sampling.

Adult↗
PubMed1984

[So-called pocket-sized spirometry versus respiratory function tests: a comparative study of vital capacity, forced expiratory volume in 1 second and Tiffeneau's coefficient].

A simplified preoperative respiratory assessment was carried out in order to assess the reliability of a pocket-sized spirometer. 30 patients were each tested using two methods: 1) the traditional extensive laboratory lung function tests and 2) a bedside test using a pocket-sized spirometer, which measured the vital capacity (VC), the forced expiratory volume in 1 second (FEV1), the peak flow (PEF) and the ratio of FEV1 to VC. The correlation between the two series of VC and FEV1 measurements was highly significant (p less than 0.001). Therefore, these two parameters could be considered as reliable when testing was performed at the bedside. However, the sensitivity of the FEV1/VC ratio was decreased; in three of the patients, the significance of this third parameter was not the same with the two methods. Measurements of peak flow were only collected at the bedside, and a statistical comparison was not established. Analysis of this last parameter always allowed us to confirm or not an obstructive syndrome when the values of FEV1 or FEV1/VC were in disagreement. The pocket-sized spirometer would seem to be a simple and reliable means of diagnosing respiratory insufficiency, its type (obstructive or restrictive) and its seriousness.

Aged↗
PubMed2004

Correlation of nasal inflammation and nasal airflow with forced expiratory volume in 1 second in patients with perennial allergic rhinitis and asthma.

BACKGROUND: Allergic rhinitis and asthma are frequently associated and are characterized by TH2-dependent inflammation. Nasal and bronchial obstruction largely depend on allergic inflammation. OBJECTIVE: To evaluate the relationships among nasal eosinophil counts, interleukin 4 (IL-4) and interferon-gamma (IFN-gamma) levels, nasal airflow, and forced expiratory volume in 1 second (FEV1) in patients with perennial allergic rhinitis and asthma. METHODS: Eight men and 7 women (mean +/- SD age, 24.8 +/- 4.7 years) with perennial allergic rhinitis and asthma were evaluated. All 15 patients had a moderate-to-severe grade of nasal obstruction. Total symptom score, rhinomanometry, nasal lavage, nasal scraping, and spirometry were evaluated in all patients. Eosinophils were counted using conventional staining; IL-4 and IFN-gamma levels were measured by immunoassay in fluids recovered from nasal lavage. RESULTS: Significant positive relationships were demonstrated between eosinophil infiltration and IL-4 levels, nasal airflow and IFN-gamma levels, FEV1 and IFN-gamma levels, and nasal airflow and FEV1 (P < .001 for all). Significant negative relationships were demonstrated between eosinophil infiltration and IFN-gamma levels, IL-4 and IFN-gamma levels, eosinophil infiltration and nasal airflow, IL-4 values and nasal airflow, nasal eosinophil counts and FEV1, and IL-4 values and FEV1 (P < .001 for all). CONCLUSIONS: There is a close association between TH2 cytokines and eosinophil infiltration in the nose. There is also clear evidence concerning the relationships among eosinophil infiltration, IL-4 and IFN-gamma levels, and nasal airflow. Nasal eosinophil, IL-4, and IFN-gamma levels correlate with FEV1. Finally, nasal airflow is related to FEV1. These findings constitute the first evidence of a relationship between TH2-related nasal inflammation and nasal and bronchial airflow in patients with perennial allergic rhinitis and asthma.

Adult↗
PubMed1985

Effect of a mixture of pyridostigmine and atropine on forced expiratory volume (FEV1), and serum cholinesterase activity in normal subjects.

Pyridostigmine 0.143 mg kg-1 (maximum 10 mg) and atropine 0.0143 mg kg-1 (maximum 1 mg) were administered i.v. to six healthy male volunteers. Peripheral venous blood samples were drawn for measurement of serum cholinesterase activity. Maximum inhibition of the enzyme was found 5 min after injection with a decrease to 27 +/- 5% (mean +/- SEM) of the original activity. Forced expiratory volume in the first 1s (FEV1) was measured at fixed time intervals for 90 min. No decrease in FEV1 was observed; on the contrary, there was a small increase. We conclude that atropine effectively antagonizes the muscarinic side-effects of pyridostigmine on bronchial smooth muscle tone and bronchial secretions, when administered in clinical doses to normal human subjects.

Adult↗
PubMed1997

Comparison between peak expiratory flow and forced expiratory volume in one second (FEV1) during bronchoconstriction induced by different stimuli.

To evaluate the sensitivity of peak expiratory flow (PEF), obtained by portable peak flow meter, in detecting mild changes in airway caliber as assessed by forced expiratory volume in 1 sec (FEV1), we studied 184 subjects who underwent different bronchial challenge tests for suspected bronchial asthma. We measured FEV1 and PEF during bronchoconstriction induced by different stimuli: allergen, methacholine, toluene diisocyanate vapors, exercise, or distilled water inhalation; a total of 186 tests were examined. Before and at different times after challenge, FEV1 was measured, and immediately after, PEF was obtained by Mini-Wright or Assess Peak Flow Meter; each time FEV1 and PEF were taken as the best of three satisfactory tracings. The median FEV1 change from baseline value of all steps in the different challenge tests was 7.5% (range: 0-66%). The correlation coefficients between FEV1 and PEF percent changes in different challenge tests were low (Spearman's p: 0.27-0.69), with high scattering of the data. The concordance between classes of percent changes in FEV1 and PEF was also low (Cohen's weighted kappa: 0.28-0.42). In subjects with a FEV1 fall > 15% after challenge, the median PEF change after bronchoconstriction was lower than the corresponding FEV1 change [17% (0-52) vs. 27% (17-66)]. When different cutoff limits of PEF percent change were considered, the sensitivity of PEF to detect a significant change in FEV1 (15 or 20% change) during bronchoconstriction was low; specificity was in general higher than sensitivity. We conclude that PEF and FEV1 changes are poorly related during mild bronchoconstriction induced by different stimuli. The low sensitivity of PEF to detect mild changes in airway caliber may represent a limit in the use of PEF in the day-to-day monitoring of asthma.

Allergens↗
PubMed1982

Relation between tracheal size and forced expiratory volume in one second in young men.

Maximal expiratory flow-volume curves and spirometry were measured in 49 white, nonsmoking, asymptomatic men 19 to 23 yr of age and 179 to 184 cm tall. Because of the uniformity of sex, age, height, and ethnic group, conventional predicted values for these men were virtually identical. Nevertheless, the between-subject coefficient of variation in spirometric and maximal flow results varied from 10% for vital capacity (VC) and forced expiratory volume in one second (FEV1) to 29% for maximal flow when 25% of VC remained to be expired. Confirming previous results, between-subject coefficient of variation was not reduced by expressing flow as VC/s instead of L/s. Eighteen of these men had standard posteroanterior and lateral chest radiographs to measure tracheal diameters at total lung capacity. Both tracheal cross-sectional area and anteroposterior diameter were positively related to FEV1 (r = 0.73, p = 0.001), the relationship being slightly stronger than with peak expiratory flow. There was a trend for VC also to be related to tracheal dimensions. As 50% of residual between-subject variation in FEV1 in these men was accounted for by variation in tracheal size, predicted values of FEV1 in an individual subject might be usefully refined by measuring tracheal size in epidemiologic surveys, thus allowing interpretation of small deviations from mean predicted values. Further studies are required on the variation in tracheal size in a more heterogeneous population.

Adult↗
PubMed1995

The role of measuring forced expiratory volume in one second in determining therapeutic changes made in an asthma clinic in general practice.

In order to determine whether spirometric measurements in a primary care asthma clinic added useful information to symptom assessment and peak flow recordings, a retrospective audit of manual case records was conducted on patients attending an urban general practice asthma clinic. Sixty-three patients were identified in whom 108 increases in treatment at the clinic had been recorded and the associated determinants of these changes were extracted from their case notes. Therapeutic changes associated with the following determinants alone were only found in single instances: presence of or changes in symptoms, inhaler technique deficiency, forced expiratory volume in 1 s (FEV1) less than 75% of the predicted value and peak expiratory flow (PEF) rate less than 75% of the predicted value. In no instance did changes in FEV1 or in PEF alone occur. The addition of spirometric measurements in this sample of patients only made an obvious difference to decision-making in four instances (4%). Therefore, the role of spirometers in the management of asthma in general practice needs further consideration and clarification on a wider scale before limited resources, whether in terms of time or money, are committed to their use.

Adolescent↗
PubMed1993

Bronchial responsiveness to inhaled histamine in both adults with intrinsic and extrinsic asthma: the importance of prechallenge forced expiratory volume in 1 second.

BACKGROUND: Recent evidence suggests that both nonspecific bronchial hyperresponsiveness and degree of airflow obstruction may be involved in the deterioration of lung function observed in patients with bronchial asthma. To investigate to which degree the level of bronchial hyperresponsiveness reflects the size of the airways at the time of testing, we examined the relationship of nonspecific bronchial responsiveness to prechallenge pulmonary function in adult asthmatic patients. METHODS: Bronchial responsiveness to inhaled histamine was measured in 100 patients (age range, 28 to 79 years), of whom 62 had intrinsic and 38 had extrinsic asthma. Histamine responsiveness was analyzed by means of the dose-response slope (DRS). RESULTS: No significant difference in prechallenge forced expiratory volume expressed as a percentage of predicted value (FEV1%pred), duration of asthma, smoking habits (pack years), or bronchial responsiveness (DRS) was found between the patients with intrinsic and those with extrinsic asthma. The patients had, in general, reduced pulmonary function, because 80% had a prechallenge FEV1 less than 80%pred. The DRS displayed a significant inverse relationship to the prechallenge level of FEV1%pred in both patients with intrinsic asthma and those with extrinsic asthma (p < 0.000001); the initial FEV1%pred accounted for approximately 35% of the variance in measurements of histamine responsiveness. Excluding patients with abnormal prechallenge FEV1 (< 70%pred), or current and exsmokers (never smoked: n = 67) from the analysis did not change these findings. CONCLUSION: Nonspecific bronchial responsiveness is to some extent determined by the prechallenge level of pulmonary function in both adults with intrinsic and extrinsic asthma.

Adult↗
PubMed1994

Acute effects on forced expiratory volume in one second and longitudinal change in pulmonary function among wood trimmers.

Wood trimmers are exposed to molds that periodically grow on timber, and may develop acute as well as chronic pulmonary function impairment. This study examined whether these acute changes in pulmonary function are predictors for a longitudinal deterioration in pulmonary function, beyond normal aging and exposure. Across-shift changes in pulmonary function, measured during a working week, were evaluated in 15 wood trimmers with a follow-up time of 27 months. Twenty-six sawmill workers, employed at the same plants as the wood trimmers, served as control subjects. The highest concentration of viable mold spores for the wood trimmers was 10(6) colony-forming units (cfu)/m3, i.e., several times higher than the corresponding value for the sawmill workers. At the follow-up, wood trimmers had a lower forced vital capacity (FVC) on average, after adjustment for age and height, compared to the sawmill workers. In addition, a correlation was found between the across-week change in forced expiratory volume in 1 second (FEV1) and the decline in FEV1 between the first and the second occasion, after adjusting for normal aging in nonsmoking wood trimmers (r2 = 84%, p < 0.001). The results from the present study suggest that across-shift decrease in FEV1 (measured during a working week) might serve as a guide to identify subjects being at risk for a further decrement in pulmonary function over and above the effects of normal aging and exposure to mold spores in the wood trimming department.

Air Pollutants, Occupational↗
PubMed2002

Influence of jacket tightness and pressure on raised lung volume forced expiratory maneuvers in infants.

While the use of the raised volume rapid thoraco-abdominal compression (RVRTC) technique has been shown to provide new insights into airway and pulmonary pathophysiology in infants, and appears to resemble the spirometric techniques used in older subjects, there is as yet no consensus regarding measurement procedures, which are known to vary considerably between laboratories (Gappa [1999] Pediatr Pulmonol 28:391-393). The aims of this study were to assess the effects of tightness of jacket fit, the efficiency with which pressure is transmitted from the jacket to the intrathoracic airways, and the effect of jacket pressure on parameters derived from the RVRTC technique. Paired forced expiratory maneuvers were performed in 20 infants with the jacket snugly or loosely wrapped around the infant's torso, and in a further 21 infants using "optimal" or a higher jacket pressure (P(j)) (1-2 kPa above "optimal" P(j)). When either a loosened jacket or a higher than "optimal" P(j) was used, forced expired flow at low lung volumes (FEF(75)) was significantly reduced by, on average, 8% and 7%, respectively. There were, however, minimal changes in forced vital capacity (FVC) or forced expired volume in 0.4 sec (FEV(0.4)). The observed changes may have been due to the increased pressure transmitted to the intrathoracic structures under these experimental conditions, and emphasize the need to assess optimal jacket pressure within each infant when using the RVRTC technique. In addition, when using a loosened jacket or a higher than "optimal" P(j), chest wall and upper airway reflexes such as glottic closure, peripheral airway closure, and negative flow dependence were more evident.

Confidence Intervals↗
PubMed1975

Lung function in childhood. I. The forced expiratory volumes in healthy children using a spirometer and reverse plethysmograph.

Measurements of FEV0-5, FEV0-75 and FEV1 and FVG have been made on 241 healthy schoolchildren using a spirometer and a reverse plethysmorgraph system. The results obtained by the two systems were very similar. The FEV0-75 was selected as the most appropriate forced expiratory volume for routine clinical use. Normal data charts for FEV0-75 and FVG are presented.

Adolescent↗
PubMed1987

Effect of effort on measurement of forced expiratory volume in one second.

The American Thoracic Society recommends that the largest FEV1 be reported from a set of forced expiratory vital capacity maneuvers performed with maximal expiratory effort. However, increased expiratory effort can decrease the FEV1. When we evaluated the peak expiratory flow rate (PEFR) in 5 normal subjects, measured from flow-volume curves, as a noninvasive index of expiratory effort, it was positively correlated with indices of effort obtained by using an esophageal balloon. We then measured the difference (dFEV1)between the largest FEV1 and FEV1 from the maneuver with the highest PEFR during 10 test sessions in 10 normal subjects. Thus, dFEV1 was always greater than or equal to 0. The mean dFEV1 was 110 ml for all sessions but decreased to 80 ml when maneuvers with poorly reproducible PEFR or forced expiratory vital capacity values were discarded. We also reviewed 9.471 spirometry sessions from outpatients and found dFEV1 to be greater than 50 ml in 26% of this population and greater than 151 ml in 7%. We concluded that during standard spirometry, FEV1 is inversely dependent on effort. Maximal effort decreases FEV1 because of the effect of thoracic gas compression on lung volume. We recommend that values from spirometry maneuvers that demonstrate submaximal effort, indicated by a decreased PEFR, be discarded. The flow-volume curve display of superimposed efforts facilitates the recognition of submaximal efforts.

Biophysical Phenomena↗