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PubMed1991

Individualized aerobic and high intensity training for asthmatic children in an exercise readaptation program. Is training always helpful for better adaptation to exercise?

In order to define the role of individualized training intensity in a conditioning program for asthmatic children, we have trained seven asthmatics (age = 11.4 +/- 1.8 years) at their ventilatory threshold (VTh) intensity level for a three-month period (aerobic training) and at maximal intensity also for three months (high intensity training). VTh is the point at which a nonlinear increase of VE occurs. Another group of seven asthmatics (age = 11.4 +/- 1.5) served as control subjects. Cardiopulmonary fitness was determined on a cycle ergometer before and after each training session. This study demonstrated that aerobic training, correctly adapted to the child's physical ability, induces the following: (1) a rapid and marked cardiovascular fitness increase; and (2) a decrease in VE over a given work range so that VTh is increased. This is of great importance because hyperventilation is a major determinant of exercise-induced bronchospasm. In contrast, even if high intensity training is well tolerated in an indoor swimming pool, the long-term effects are unsuitable for asthmatic children because the decrease of VTh will involve an increase of hyperventilation, even when exercise is performed at submaximal intensity.

Adaptation, Physiological↗
PubMed1989

Reference values of total respiratory resistance, determined with the "opening" interruption technique.

In a large epidemiological survey of lung function the subjects performed maximum expiratory flow volume (MEFV) manoeuvres. They were also interviewed by trained interviewers using a standardized questionnaire. In a random subset of the subjects the resistance of the respiratory system was measured with the "opening" interruption technique, in which the mouth pressure before the end of the interruption period is divided by the flow shortly after the end of it. The subset contained men and women, and smokers as well as nonsmokers, 229 of whom were considered to be healthy because they had no history of complaints and a "normal" flow-volume curve. In this group mean inspiratory and expiratory resistances did not differ significantly (0.27 and 0.29 for men and 0.39 and 0.38 kPa.l-1.s for women). The averages of in- and expiratory resistance were 0.28 +/- 0.10 kPa.l-1.s for men and 0.39 +/- 0.11 kPa.l-1.s for women. The resistance values were slightly but significantly correlated with body height, FEV1 and MEF50, but not with smoking habits. Due to the considerable variability the method does not permit sharp discrimination between normal and abnormal subjects. However, it appears to be useful in histamine challenge testing, to detect and monitor bronchial asthma, being not subjected to the disturbing effect of forced ins- and expirations.

Adult↗
PubMed1988

Cross-sectional study of uranium mine workers to develop predictive equations for lung functions with reference to chronic obstructive pulmonary disease.

As the first part of a prospective epidemiological study of the lung function and dust exposure of workers at the Rössing Uranium Mine in SWA/Namibia, various measurements of lung function of 1,407 workers were carried out. This was necessary in order to follow up any chronic obstructive pulmonary disease that might develop. The opportunity was used to test existing prediction formulae and to develop formulae for normal values for workers at the Rössing mine.

Adult↗
PubMedDate not supplied

[Flow-volume curves in healthy children and adolescents 10-19 years of age. Reference values and lower limits of the normal].

In 477 healthy children and adolescents (247 boys and 230 girls, aged 10 to 19 years), we measured the vital capacity (VC), the forced expiratory volume in one second (FEV1), the flow between 25 and 75% of expired forced vital capacity (FEF25-75) and the forced expiratory flows when 75, 50 and 25% of forced vital capacity remain to be expired (FEF75, FEF50, FEF25), in order to determine reference values and lower limits of the normal. Regression functions were calculated for girls and boys separately. The best correlations for pulmonary volumes and flows were obtained by taking into account simultaneously height and age in girls, height, age and weight in boys. Power function is the model of regression that fits our data the best. The regression functions determined, as well as the lower limits of the normal and the residual standard deviations, are given by sex for each of the variables measured. These results are discussed and compared with those in literature. They concern clinicians (identification of "abnormal" subjects) and epidemiologists (prevalence of ventilatory troubles, comparison of different populations), and can be used in adolescents of the same age groups.

Adolescent↗
PubMed1995

Spirometric patterns in childhood asthma: peak flow compared with other indices.

The objective of this study was to determine patterns of pulmonary function abnormalities and to evaluate how adequately peak flow monitoring was correlated to other spirometric indices in childhood asthma. Ninety-one children, aged 8-15 years, with moderate-to-severe asthma were repeatedly tested in a summer camp. On-site medical staff permitted 24-hour-a-day supervision. Subjective and objective clinical evaluations of asthma status were made over 14 consecutive days. Detailed clinical history and clinical observations were made by an experienced staff, and a total of 2,663 pulmonary function tests were performed regularly three times daily and whenever a child sensed asthma symptoms. Patterns of obstruction were divided into large airway abnormalities and small airway abnormalities. There was a low concordance between standard large airway measures, such as the peak expiratory flow rate (PEFR) or the forced expiratory volume in 1 second (the FEV1), and measures of small airway obstruction, such as the forced expiratory flow rate 25-75% (FEF25-75). Normal PEFR measurements do not always indicate that all other pulmonary function measures are normal. In fact, 18% of children with a normal PEFR had abnormal FEF25-75 values. Results demonstrated that the FEF25-75 was the most specific and sensitive measure of airway obstruction. PEFR is widely used to monitor asthma symptoms objectively because it is technically simple to perform, relatively inexpensive, and helpful in most cases. It is, therefore, appropriate for asthma education programs to recommend PEFR as an objective measure to guide in making therapeutic decisions. Our data and clinical observations support the "Guidelines for the Diagnosis and Management of Asthma" of the NIH Health Asthma Education Program that suggest that children have more complete pulmonary function testing along with frequent PEFR measures. Many children may appear asymptomatic, while recording normal PEFR measures, and still having significant asthma. Repeated pulmonary function testing and evaluation of the pattern of respiratory obstruction aids in managing this challenging group. We recommend that efforts be made to develop a simple and inexpensive method of measuring FEF25-75 that will allow this measurement to be made even at home.

Adolescent↗
PubMed1996

Value of high-resolution computed tomography in routine evaluation of lung transplantation recipients during development of bronchiolitis obliterans syndrome.

BACKGROUND: Chronic rejection is a major long-term complication after lung transplantation. The purpose of our study was to evaluate the role of repeated high-resolution computed tomographic examinations in monitoring the development of bronchiolitis obliterans syndrome after lung transplantation. METHODS: A total of 126 high-resolution computed tomographic examination in 13 lung transplant recipients was analyzed. During a mean follow-up period of 23 months, bronchiolitis obliterans syndrome developed in eight of the patients. A scoring system from 0 to 10 based on the number of chronic changes on high-resolution computed tomography was developed, and the score of each patient was compared with decline in the forced expiratory volume in 1 second and maximal forced expiratory flow rate of 50% of the forced vital capacity. RESULTS: The score of chronic changes, measured at 1 year after transplantation, correlated inversely with the values of forced expiratory volume in 1 second and maximal forced expiratory flow rate at 50% of the forced vital capacity (p < 0.05). Stage I bronchiolitis obliterans syndrome was associated with scores of 4 to 6 (mean 5.0), stage 2 with scores of 6 to 9 (mean 7.0), and stage 3 with scores of 6 to 9 (mean 7.7). The sensitivity of high-resolution computed tomography was 93% and its specificity was 92% when five chronic changes were used as a cutoff level. CONCLUSIONS: The progress of chronic changes on high-resolution computed tomography occurs concurrently with the development of bronchiolitis obliterans syndrome. High-resolution computed tomography may provide additional morphologic information for noninvasive evaluation of chronic lung rejection.

Adult↗
PubMed1976

The maximal expiratory flow-volume curve. Normal standards, variability, and effects of age.

From a randomly selected population representative of the white population of Tucson, Ariz., satisfactory flow-volume data were obtained for 3,115 persons. Data from the 746 subjects who were totally free of symptoms or history of cardiorespiratory disease and who had never smoked were used in determining "normal" prediction equations for spirometric parameters and maximal expiratory flows. The maximal expiratory flow-volume curve showed considerable intersubject variability, but little change in shape of the mean maximal expiratory flow-volume curve was seen with advancing age when the effects of disease, insult, or injury were excluded.

Adolescent↗
PubMed1985

Flow volume loops.

Explore the source record for details and available documents.

Forced Expiratory Flow Rates↗
PubMed2000

Environmental exposure to air pollution and allergens and peak flow changes.

Laboratory-based studies have shown that ozone and nitrogen dioxide can potentiate the effect of allergen in sensitized asthmatic subjects, but it is not known whether this interaction is important under natural exposure conditions. Thirty-five subjects with clinical diagnoses of asthma or chronic obstructive pulmonary disease and with a provocative dose causing a 20% fall in forced expiratory volume in one second methacholine <12.25 micromol (using the Yan method) kept peak expiratory flow (PEF) records for a 4-week period during late summer, with concurrent measurement of spore and pollen counts and pollution levels. Multiple regression analysis was then used to determine the effect on PEF of aeroallergen, and of the interaction between aeroallergen and pollutant levels. A statistically significant interaction was demonstrated between total spore count and ozone, but not nitrogen dioxide. Mean PEF fell in association with increasing spore count (same-day and 24-h lag level) and PEF variability increased with increasing spore count (24-h lag level only); both changes were greater the higher the prior ozone level. These results suggest that ozone can potentiate the effect of aeroallergens in subjects with bronchial hyperreactivity under natural exposure conditions. However, the effect was small, and the clinical significance of the interaction requires further study.

Adult↗
PubMed1992

Altered epithelial lining fluid parameters in old normal individuals.

Pneumonia is a leading cause of morbidity and death in older patients, and immunosenescence is believed to contribute to their susceptibility. In order to investigate whether age-related changes occur on the epithelial surfaces of the lung, bronchoscopy and bronchoalveolar lavage (BAL) were performed without complication in 19 young (27.7 +/- 4.2 yrs), 6 middle-aged (49.8 +/- 3.5 yrs), and 8 old (74.1 +/- 4.3 yrs) normal, nonsmoking subjects. BAL was performed by instilling and retrieving five 20 ml aliquots of normal saline into three sites. The returns from the first aliquots (the bronchial sample) were analyzed separately from the returns from the subsequent aliquots (the distal sample). Lavage fluid cellularity was characterized and IgA, IgG, and albumin were measured by ELISA. Lavage fluid returns were lower in the elderly group and correlated with spirometric parameters. Significantly elevated numbers of neutrophils were recovered by the bronchial sample fluid from the old group. In contrast, no consistent difference in macrophage recovery by either the bronchial or distal sample was noted. In both the bronchial and distal samples, IgG, but not IgA or albumin, was elevated in the group of old subjects. Alterations occurring in BAL fluid with aging may reflect changes in local host defenses.

Adult↗
PubMed1997

[Forced expiration. Various current concepts, 50 years after Robert Tiffeneau].

One hundred and fifty years after the original description of spirometry by Hutchinson and 50 years after the definition of his famous ratio by Tiffeneau, a certain number of physiological advances have enabled a better understanding of the determinants of the forced expired manoeuvre and to mitigate some of its inconveniences. This review focuses on three of these advances. The first is the influence of an inspiratory manoeuvre which precedes a forced expiration, on the expiratory flow. This influence is probably a consequence of viscoelastic phenomena and impose some strains on standardisation in current practice. The second is the possibility of detecting in a reproducible and simple fashion, without the need for co-operation on the part of the subject, a limitation in expiratory flow by the application of a negative expiratory pressure at the opening of the airways (NEP for negative expiratory pressure). The third is the possibility to verify in a simple fashion the quality of the expiratory performance achieved by the patient and thus to detect an insufficient effort in the force of a falling expiratory flow.

Dyspnea↗
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↗
PubMed1990

Tracking of lung function in healthy children and adolescents.

Two hundred twenty-six healthy school children, with a mean age of 8.8 years; 62 girls mean age 8.8, 48 boys mean age 12.6 and 51 girls mean age 12.6 years at the start, were enrolled in a longitudinal study of lung function and tested annually for 5 years. All were free of respiratory symptoms, and none smoked more than five cigarettes per week during the 5 years. Static and dynamic lung volumes (other than residual volume), maximum expiratory and inspiratory flows, and maximum mouth pressures "track," that is, individuals remain at a constant deviation from the sample mean over time. The data indicate that these measurements of lung function in healthy individuals grow in constant proportion relative to other healthy children and adolescents.

Adolescent↗