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PubMed1997

Short-term variations in oscillatory and spirometric lung function indices among school children.

The aim of this study was to compare immediate, daily and weekly variation in respiratory resistance measured by means of the forced oscillation technique (Rrs,FOT) to spirometric indices in 7-12 year old children with chronic respiratory symptoms. The lung function measurements were performed in 19 children on 4 days, i.e. two consecutive days during two consecutive weeks. On each day, the measurements were carried out at the same time of day and always repeated three times. In addition, Rrs,FOT and spirometric lung function indices were compared with an exercise challenge test in 12 children. Intrasubject coefficients of variation (CoVs) for Rrs,FOT were larger than those for spirometric indices. Only in the immediately repeated measurements was the CoV of maximal expiratory flow at 25% vital capacity larger than that of Rrs,FOT (16.6 vs 14.9%). At all time intervals, the smallest CoVs were observed in forced vital capacity (FVC) or in the ratio of forced expiratory volume in one second to FVC (2.0-2.6%). When excluding Rrs,FOT values which were not within 2 SD (0.11 kPa.L-1.s) of the differences between the immediately repeated measurements, the CoV of the immediately repeated measurements of Rrs,FOT was reduced to 9.1%, being smaller than that of maximal mid-expiratory flow (10.1%). However, even then the day-to-day variation in Rrs,FOT was clearly larger (16.0%) than those of the airflow indices at specified lung volumes (7.2-8.3%). This was also true for the weekly variation. In the exercise challenge test, there were larger changes in Rrs,FOT values than in the spirometric indices, but Rrs,FOT was the most sensitive index to detect changes in the respiratory system. In conclusion, the variation in Rrs,FOT values was larger than that of most spirometric indices. When a reliability index was applied, the immediate variation in Rrs,FOT values was comparable to those of the airflow indices at specified lung volumes. Rrs,FOT was also the most sensitive index in the exercise challenge test, and therefore it seems to be suitable for detection of short-term functional changes in the respiratory system. However, the relatively low repeatability of Rrs,FOT over days and weeks may limit its applicability to longer-term follow-ups.

Airway Resistance↗
PubMed1993

Pulmonary function and hypoxic ventilatory response in subjects susceptible to high-altitude pulmonary edema.

To determine if spirometric changes reflect early high-altitude pulmonary edema (HAPE) formation, we measured the FVC, FEV1, and FEF25-75 serially during the short-term period following simulated altitude exposure (4,400 m) in eight male subjects, four with a history of HAPE and four control subjects who had never experienced HAPE. Three of the four HAPE-susceptible subjects developed acute mountain sickness (AMS), based on their positive Environmental Symptom Questionnaire (AMS-C) scores. Clinical signs and symptoms of mild pulmonary edema developed in two of the three subjects with AMS after 4 h of exposure, which prompted their removal from the chamber. Their spirometry showed small decreases in FVC and greater decreases in FEV1 and FEF25-75 after arrival at high altitude in the presence of rales or wheezing on clinical examination and normal chest radiographs. One of the two subjects had desaturation (59 percent) and tachycardia during mild exercise, and excessive fatigue and inability to complete the exercise protocol developed in the other at 4 h. The six other subjects had minimal changes in spirometry and did not develop signs of lung edema. Further, we measured each subject's ventilatory response to hypoxia (HVR) prior to decompression to determine whether the HVR would predict the development of altitude illness in susceptible subjects. In contrast to anticipated results, high ventilatory responses to acute hypoxia, supported by increased ventilation during exposure to high altitude, occurred in the two subjects in whom symptoms of HAPE developed. The results confirm that HAPE can occur in susceptible individuals despite the presence of a normal or high ventilatory response to hypoxia.

Adult↗
PubMed2006

Testing of pulmonary function in a professional cycling team.

AIM: Asthma affecting elite athletes has been studied mainly in subjects practicing winter sports. The aim of our study was to test the pulmonary function in order to evaluate bronchial hyper-responsiveness prevalence in a team of 25 male professional cyclists (27.9+/-3.9 years old with a VO(2max) equal to 69.9+/-6.6 mL.min(-1) x kg(-1)). METHODS: Using a questionnaire that queried the presence or absence of asthma history or common symptoms of exercise induced bronchospasm, 72% of the subjects had upper airway or bronchial symptoms. Using a pneumotachograph, we recorded a forced flow-volume curve at rest, after a maximal exercise test with ambient air, and after beta2-agonist inhalation, then during a methacholine challenge. RESULTS: In our study, 52% of the subjects showed clinical symptoms associated with bronchial responsiveness during methacholine test, a proportion which is much higher than the average population (3-20%). However, ERS-ATS pulmonary function testing criteria at rest (reduced FEV1, FEV1/FVC, FEF25-75%) were not fulfilled by any of them. In the asthmatic group, O2max was significantly higher (70.5+/-6 vs 68.6+/-8.2 mL.min-1.kg-1, P<0.05). This remained true for submaximal loads suggesting that ventilation energy cost related to bronchial hyper-responsiveness was also higher. CONCLUSIONS: We have reported in this study that professional cyclists have a far higher prevalence of bronchial hyper-responsiveness than the average population, which can be regarded as a real health issue.

Adrenergic beta-2 Receptor Agonists↗
PubMed1991

[Standards in evaluating the test of obstruction reversibility based on the flow-volume curves].

The study analyzed the changes in the shape of the flow-volume curve after fenoterol (Berotec) inhalation in school age healthy children. Significant increase of FEF25-75%, FEF50%, FEF25% values were seen. The authors demonstrated that bronchodilatation was not related to sex, height, weight and children's age, but it's value is indirectly proportional to the at-rest state of the airways. It seems, basing on results of this study, that FEV1 and FEF25-75% are the best indexes of dilatation tests. Increases of 10% and 30% are significant of bronchodilatation.

Adolescent↗
PubMed1979

Pulmonary function and maximum exercise responses following acute ozone exposure.

We examined changes in pulmonary function during resting exposure to concentrations of ozone at 0.75, 0.50, 0.25, and 0.00 parts/million (ppm), and determined the effect these exposures had on a subsequent maximum exercise test using filtered air. In order to determine if recovery of pulmonary function would be facilitated by increased ventilation due to maximum exercise, a control condition was conducted with subjects resting for a period equivalent to the maximum exercise condition. Eight males and five females participated in eight different conditions in order to answer these two questions. Resting 2-h exposure to 0.75 and 0.50 ppm ozone caused significant decrements in forced vital capacity of 10% and 5%, respectively. However, 0.00 and 0.25 ppm ozone induced no pulmonary decrement. None of the pollutant conditions reduced subsequent maximum exercise performance (ml O2.min-1.kg-1, heart rate, and total performance time). The pulmonary function responses after the maximum capacity test returned to pre-ozone values for the 0.50 ppm condition, but were still significantly decreased for the 0.75 ppm condition. The increased ventilatory exchanges from maximum exercise did not facilitate the return of pulmonary function. It appeared that increased ventilation during ozone exposure plays a significant role only in inducing pulmonary function decrement, but not in facilitating the return of pulmonary function to normal values.

Adult↗
PubMed1982

[Volumetric correction of the maximal expiratory flow 25-75% in chronic obstructive bronchopneumopathies].

After inhalation of a bronchodilator aerosol, indices of airway obstruction usually improve whereas the forced expiratory flow between 25 and 75% (FEF25-75%) of the forced vital capacity (FVC) commonly remains the same or may decrease. This is due to the fact that the FEF25-75% after bronchodilatation is measured at lower absolute lung volumes with subsequently less elastic recoil pressure. A goal of this study was to analyze this test after volume adjusting so that the flows before and after a bronchodilator are compared at equal volumes (isovolume). Thirty-seven men with chronic obstructive pulmonary disease (COPD) performed maximal forced expiratory maneuvers before and 15 minutes after isoproterenol (0.15 mg) inhalation. The mean value of isovolume (0.56 +/- .30 1. sec-1) was significantly greater (p less than 0.001) than the FEF25-75% recorded before (0.45 +/- .26 1. sec-1) and after (0.50 +/- .27 1. sec-1, p less than 0.01) bronchodilator inhalation. The FVC was improved in 18 patients but only 6 (33%) had an improved conventional FEF25-75%. On the other hand, isovolume FEF improved in 12 (66%) patients. Isovolume FEF also improved twice as frequently as conventional FEF25-75% in those demonstrating an improvement in forced expiratory volume in the first second (FEV1). Furthermore, when the conventional FEF25-75% demonstrated no improvement after isoproterenol inhalation, isovolume improved in 8/26 (31%) of these patients. Our results suggest that volume adjusting the FEF25-75% after isoproterenol inhalation increases its sensitivity for detecting acute bronchodilation in patients with COPD, and that this methods appears practical in routine pulmonary function testing.

Forced Expiratory Flow Rates↗
PubMed1975

[Maximal mid-exiratory flow (MMEF) in the evolution of the respiratory functional patter of silicosis. (author's transl)].

A follow up study of VC, FEV and MMEF was performed by the authors in forty silicotic patients, mainly in order to find out if MMEF were more sensitive than VC and FEV 1 IN detecting respiratory function impairment in the follow up of silicosis. In patients with moderate bronchial obstruction, a statistically significant difference was found between themean values of MMEF measured in two different instances: such a finding suggests a greater MMEF reduction in the early stages of silicosis. In 22 subjects with moderate respiratory function impairment (VC and FEV1 less than or equal 40% predicted values), MMEF was found to be, percentually, more decreased than FEV1: the difference was statistically significant. It is therefore concluded that MMEF changes in the follow up examination of silicosis are more sensitive than other functional indexes.

Forced Expiratory Flow Rates↗
PubMedDate not supplied

Time course of lung function and exercise performance after heart transplantation.

To study the time course of exercise performance and the diffusion capacity after heart transplantation, we submitted two groups of patients to graded symptom-limited supine exercise. Patients in group 1 (n = 11) underwent operation 12.9 +/- 7.0 months before the study; those in group 2 (n = 10) underwent operation 53.9 +/- 14.8 months before the study. Respiratory and cardiovascular parameters were evaluated noninvasively at rest, at individual peak exercise, and 10 minutes later with a commercially available Sensormedics MMC 4400 metabolic measurement chart. Short-term survivors exhibited a lower maximum work capacity compared with that of long-term survivors (63.6 +/- 25.9 versus 100 +/- 50 W, p < 0.05), with a concomitant lower terminal heart rate (123 +/- 19 versus 137 +/- 17 beats/min, p < 0.05) that accounts for the lower cardiac output in this group, but statistical significance was not achieved (13.0 +/- 4.6 versus 17.5 +/- 6.3 L/min, not significant). Interestingly, significant differences were also observed for diffusion capacity before exercise (11.9 +/- 4.8 versus 19.3 +/- 7.3 ml/min/mm Hg, p < 0.05). The improvement of the diffusion capacity may be associated with a time-dependent change in the diffusion characteristics of the alveolocapillary membrane.

Azathioprine↗
PubMed1994

Comparison of cardiac pacing modes in patients with chronic obstructive pulmonary disease.

STUDY OBJECTIVE: This study compares the relative benefits of dual chamber adaptive rate pacing (DDDR) with ventricular adaptive rate pacing (VVIR) in patients with chronic obstructive pulmonary disease (COPD). STUDY DESIGN: Cardiac hemodynamics were evaluated with serial exercise tests. A minimum of 2 h was allowed between studies. Pulmonary gas exchange was measured and cardiac output (CO) was determined at rest and immediately after maximum exercise by Doppler echocardiography. PATIENTS: Sixteen patients with DDDR pacemakers were studied. Eight patients had COPD and eight patients had normal lung function (NLF). Baseline lung function was documented with spirometry. INTERVENTIONS: The patients with NLF functioned as a control group. Prior to entry into the study, the rate-modulated parameters of the pacemaker were programmed to a clinically determined optimal set of parameters for each individual patient. These were not changed for the duration of the study. RESULTS: Both groups showed a statistically significant improvement in exercise duration, CO at maximum exercise, and cardiac output difference (CODiff) with the dual chamber adaptive rate pacing mode (DDDR). (COdiff is the change in CO from rest to maximum exercise.) Patients with NLF also showed a significant improvement in anaerobic threshold (AT) and VCO2 max with DDDR. Patients with lung disease showed a statistically significant improvement at all levels of exercise in the ventilatory equivalent for oxygen. CONCLUSION: In this study, those patients with chronic lung disease who required cardiac pacing performed significantly better in the DDDR mode as compared with the VVIR mode. Therefore, the DDDR pacing mode should provide an improved quality of life for the patient with COPD who also requires cardiac pacing.

Aged↗
PubMed1988

Spirometry and maximal expiratory flow-volume curve reference standards for Polynesian, European, and Chinese teenagers.

Lung function was compared and reference standards were determined in 1,007 Polynesian, European, and Chinese teenagers attending school in Tahiti (517 boys, 490 girls; mean age, 14.4 years). Spirometric study results and maximal expiratory flow-volume curves were measured using techniques recommended by the American Thoracic Society. Age, standing height, and weight were chosen as the independent variables for males, and age and standing height for females. Regression equations constructed with logarithmically transformed dependent variables provided accurate predictions. We observed significant racial differences: in the Europeans, forced vital capacity (FVC) and forced expiratory volume in one second (FEV1) were higher than the mean values predicted for the whole study population, while forced expiratory flow during the middle half of the FVC (FEF25-75%) and maximal expiratory flows after 25, 50, and 75 percent of FVC had been exhaled (V max 25, 50, and 75, respectively) were about equal to the mean values; in the Polynesians, volumes and flows were mostly lower than the mean; in the Chinese, FVC in boys and girls, and FEV1 in girls only, were lower, while the other flows were higher. The FEV1/FVC, FEF25-75%/FVC, Vmax25/FVC, Vmax50/FVC, and Vmax75/FVC were significantly higher than the mean in the Chinese boys and girls and often lower in the Europeans.

Adolescent↗
PubMed1975

Grading, time course, and incidence of exercise-induced airway obstruction and hyperinflation in asthmatic children.

We evaluated clinical status and pulmonary function in 60 perenially asthmatic and 11 normal children before and repeatedly after incrementally increasing bicycle ergometer exercise. The changes in clinical status and pulmonary function which were elicited by strenuous exercise were graded by an air exchange and a physiological grading system respectively. Normal children showed no significant clinical or physiological changes after exercise. Strenuous exercise elicited significant deteriorations in clinical and physiological measurements in 36% to 77% of asthmatic girls and 46% to 90% of asthmatic boys, the frequency depending on the test used to determine exercise-induced abnormalities. The incidence of exercise-induced asthma (EIA) was statistically significantly higher in asthmatic boys than girls. The higher incidence of EIA in boys was primarily due to a larger number of very severe attacks in boys than girls; mild and moderate EIA was about equally common in the two sexes. Most patients with EIA developed large and small airway obstruction, although large airway obstruction tended to be the predominant and the more severe abnormality. Clinical and physiological abnormalities, regardless of severity, were usually most marked during the first ten minutes after exercise and lessened thereafter. Mild EIA usually lasted for only 15 minutes or less; severe EIA improved, but usually did not resolve within 35 minutes of exercise. There were three patinets in whom the severity of EIA got worse after exercise and an additional seven in whom the improvement was minimal. In these ten patients isoproterenol aerosol terminated EIA, indicating that exercise-induced large and small airway obstruction in asthmatic children is primarily, if not solely, due to bronchospasm.

Adolescent↗
PubMed1982

Effect of oral terbutaline on exercise-induced asthma.

Spirometry before and after a treadmill exercise two hours after oral administration of 2.5-5.0 mg of terbutaline or placebo disclosed that terbutaline produced a highly significant protective effect against exercise-induced asthma. In 14 asthmatic youngsters decreases in FEV1, PEFR or FEF25-75 of at least 15% followed exercise after placebo.

Administration, Oral↗
PubMed2002

Association between air pollution and lung function growth in southern California children: results from a second cohort.

A cohort of 1,678 Southern California children, enrolled as fourth graders in 1996, was followed for 4 years to determine whether the growth in lung function of the children was associated with their exposure to ambient air pollutants. These subjects comprised the second cohort of fourth grade children participating in the Children's Health Study. Significant deficits in lung function growth rate were associated with exposure to acid vapor, NO(2), particles with aerodynamic diameter less than 2.5 microm (PM(2.5)), and elemental carbon. For example, the average annual growth rates of maximal midexpiratory flow and forced expiratory volume in 1 second were reduced by approximately 11% (p = 0.005) and 5% (p = 0.03), respectively, across the observed range of acid exposure. Exposure to acid vapor was also associated with reductions in the ratio of maximal midexpiratory flow to forced vital capacity (p = 0.02), whereas exposure to ozone was correlated with reduced growth in peak flow rate (p = 0.006). Larger deficits in lung function growth rate were observed in children who reported spending more time outdoors. These findings provide important replication of our previous findings of an effect of air pollution on lung function growth that were based on the first fourth-grade cohort from the Children's Health Study (Am J Respir Crit Care Med 2000;162:1383-1390).

Air Pollutants↗