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PubMed1988

[Reference values for the maximal expiratory flow volume curve for adults. Results of a cooperative study].

Reference values of the maximal expiratory flow-volume curve for the adult GDR's population have been ascertained by a co-operative study of 5 lung function laboratories. We analysed measurements in 1,004 healthy subjects aged 16 to 69 years (728 males and 276 females). Prediction equations for the maximal expiratory flow rates, several time constants of lung mechanics and screening parameters of ventilatory inhomogeneity have been calculated by means of the multiple linear regression analysis. Our reference values are in good accordance with SEPCR summary equations. It is recommended to subtract from or add to the predicted values 1.64 standard deviations and to consider abnormal all values beyond this limit.

Adolescent↗
PubMed1988

Bronchoconstriction due to exercise combined with cold air inhalation does not generally influence bronchial responsiveness to inhaled histamine in asthmatic subjects.

We investigated immediate and late changes in airway responsiveness to histamine, after bronchoconstriction due to exercise combined with inhalation of cold air, in ten asthmatic subjects who came on six days. On the first visit, the provocation concentration producing 20% fall in FEV1 (PC20) histamine was obtained. After functional recovery, each subject walked on a treadmill whilst breathing dry, cold air. This resulted in an immediate fall greater than 15% (mean +/- SD = 31.9 +/- 11.0%) in forced expiratory volume in one second (FEV1). Following recovery, PC20 was measured again. FEV1 was then monitored for up to 6-8 h. PC20 was measured then and on the two following days at the same time of the day. Subjects were studied on three control days using the same design except that a resting period replaced the exercise with cold air. The mean changes in PC20 at each interval after exercise combined with cold air were not statistically significant. Physiologically significant changes were obtained in only two subjects, reaching a maximum 8 h after the manoeuvre. In these subjects, changes in PC20 were reproducible during a second series of visits. It is concluded that bronchial responsiveness to histamine is not generally influenced by the bronchoconstriction due to exercise combined with cold air.

Adolescent↗
PubMed1984

[High-frequency ventilation. Development of new ventilation systems--experimental and clinical results].

Based on the well known High Frequency Jet Ventilation (HFJV) two modified types of High Frequency Ventilation, Forced Diffusion Ventilation (FDV) and High Frequency Pulsation (HFP) have been developed. Both systems are designed to allow ventilation with very small volume portions in the upper range of HFV frequencies. In dog experiments sufficient gas exchange could be maintained during FDV up to frequencies 3000 per minute and even with an uninterrupted "continuous" jet entering the lungs on carina level. With this mode of ventilation lung could be kept in a resting position. Due to particular configuration of a pair of nozzles at the tip of a modified endotracheal catheter fresh gas is forced down the airways along the inner edges of bifurcations towards the lung periphery. At the same time stale gas leaves the lung via the remaining cross section of the airways. Thus a continuous scavanging process can be established without significant lung inflation. This mechanisms are not met during HFP. Therefore the range of frequencies achievable with this type of ventilation is significantly lower (250 to 500/min.) and "tidal volumes" are much higher. However, they are still beyond the anatomical dead space which suggest again a contribution of alternative mechanisms to gas transport. The impact of both types of HFV on gas exchange and pressure-flow conditions were studied in lung models as well as in animal experiments. FDV and HFP were also applied successfully to a group of 23 patients undergoing major lung surgery. In all patients it was possible to maintain excellent gas exchange throughout the whole surgical procedure. The exposure of the surgical field was much more quiet as compared to IPPV. Due to the small tidal volumes lung pressures can be kept much lower and gas losses via the open bronchi and lung surface are reduced dramatically.

Animals↗
PubMed1984

The possible role of LTD4 in asthma in humans investigated in vivo.

The bronchoconstrictor effect of LTD4 was tested in a double blind design in 9 healthy volunteers who inhaled 10 and 40 nmol synthetic LTD4, 10 and 100 mumol histamine, and placebo on 5 different days. As the nebulized testsolutions were administered via a settling bag, an even deposition on the airways could be expected, and consequently a relative predominans of the changes measuring the airflow in the small airways. Accordingly the PEF values were reduced by less than 5% for both active substances. The function of the small airways was measured by (1) the volume of trapped gas in percentage of the total lung capacity, and (2) maximal expiratory flow rate at 30% of vital capacity above residual volume, determined from partial flow-volume curves. A dose-dependent bronchial obstruction was revealed. LTD4 was 3 to 4 decades more potent than histamine on a log molar scale. Pronounced dyspnoea and systemic side effects were experienced after inhalation of histamine whereas LTD4 did not cause any symptoms. Adrenergic beta 2-agonist (Fenoterol) was in all cases capable of reversing the LTD4 induced bronchospasm. 6 patients with verified exogenous asthma were tested in a similar double blind set-up for their reactivity to LTD4. The asthmatics were hyperreactive to LTD4.

Adolescent↗
PubMed1980

[Peripheral airway obstruction involving cardiovascular factors. A case report (author's transl)].

A patient with pronounced dyspnoea and cyanosis was found to have severe hypoxaemia with normal spirographic values. His past history included arterial hypertension, myocardial infarction and phlebitis of the lower limb. Airways resistance was normal, but maximal expiratory flow rates at low lung volume (Flow-volume curves) were reduced, suggesting "peripheral" airways obstruction. This was confirmed by the presence of pulmonary hyperinflation and mechanical non-homogeneity accompanied by unevenly distributed ventilation, as shown by alveolar nitrogen gradient. There was marked hyperventilation with hypocapnia. Since transfer values (measured by the CO single-breath method) and lung distensibility values were normal, emphysema could be ruled out as a cause of obstruction. Analysis of pressure-flow relationship confirmed that the obstruction of peripheral airways was "intrinsic" in character. It could be due to an increase in lung extravascular fluid (interstitial oedema due to left cardiac failure), or to repeated micro-emboli in the lungs, or to hypocapnia, these three mechanisms possibly being associated.

Aged↗
PubMed1983

Airway constriction in normal humans produced by inhalation of leukotriene D. Potency, time course, and effect of aspirin therapy.

Five normal human subjects inhaled aerosols generated from solutions of leukotriene D (LTD) to determine the bronchoconstrictor potency and the time course of airway obstruction produced by this constituent of slow-reacting substance of anaphylaxis. The dose-effect and time-effect curves were compared with curves similarly generated for the well-characterized airway constrictor histamine. Leukotriene D was, on average, 5,900 times more potent than histamine on a molar basis in producing an identical decrement in maximal expiratory flow rate at 30% of control vital capacity above residual volume. In addition, although LTD had a rapid onset of effect, similar to that of histamine, the airway obstruction produced by LTD was longer lasting, thereby reflecting more closely the response of asthmatic allergic individuals to antigen inhalation. The response of these subjects to inhalation of LTD was not altered by ingestion of aspirin, suggesting that the airway obstruction was not mediated by cyclooxygenase products of arachidonic acid.

Adult↗
PubMed1981

[Study of lung symptomatology and lung function in steelworkers].

We have examined 272 steelworkers, aged 45 to 55 years, by means of the ECSC-questionnaire and the following lung function tests: vital capacity (VC) and forced expiratory volume in one second (FEV1), residual volume (RV) and total lung capacity (TLC); maximal expiratory flow rates (Vmax, Vmax 50, Vmax 75); specific airways conductance (SGaw); slope of the N2 alveolar plateau after oxygen inhalation (delta N2) and the bolus closing volume (CV). The influence of smoking on respiratory symptoms and lung function was confirmed. In order to assess the influence of occupational pollution a sample of 163 workers was classified according to smoking habits and workplace (either LD-steelplant and continuous casting department, or sheet rolling mill). In the nonsmokers group we found that the workers from the steelplant and continuous casting department (n = 12) had a significantly lower SGaw value (delta = 0.065 cm H2O-1 . s-1, p less than 0.01) and a significantly higher CV value (delta = 4.5% VC, p less than 0.05) than the workers from the sheet rolling mill (n = 11). Differences in FEV1/VC, Vmax 50 and Vmax 75 were not significant, but were also consistent with a slight airflow obstruction in the steelplant workers. In the smokers (n = 99) and exsmokers (n = 41) groups no differences existed between both working categories. Our results suggest that nonsmoking workers from the steelplant and the continuous casting department have undergone moderate, but detectable effects from industrial pollution. These effects are probably masked by those of tobacco in smokers and exsmokers.

Air Pollutants, Occupational↗
PubMed1980

Familial lymphoid interstitial pneumonia: a long-term follow-up.

We describe two brothers who developed chronic pulmonary disease in early childhood. Lung biopsies were diagnostic of lymphoid interstitial pneumonia (LIP). Familial LIP has not been previously reported, and the natural history is unknown. The elder brother experienced progressive respiratory disability and died 10 years after the onset of symptoms. The younger brother age 13, has been observed for 11 years and despite progression of pathological changes revealed in his second lung biopsy, he has had few symptoms and leads an active life. Current pulmonary function tests reveal decreased lung volumes, increased maximal expiratory flow rates and decreased lung compliance. Arterial PO2 is 75 mm Hg at rest and falls to 56 mm Hg with exercise. These findings, consistent with restrictive lung disease, contrast with the obstructive ventilatory pattern seen in some adult patients.

Child, Preschool↗
PubMed1994

Qigong and L-1 straining maneuver oxygen system requirements with and without positive pressure breathing.

Based on the characteristics of respiration and the intrathoracic pressure in Qigong (Q-G) maneuvering, it has been theorized that the Q-G maneuver may lessen the lack of coordination between aircraft oxygen apparatus and anti-G maneuvers and may be more compatible with positive pressure breathing (PPB). In an experiment intended to test this hypothesis, 5 male volunteers, trained in Q-G and L-1 maneuvers, performed the Q-G and the L-1 maneuvers without and with (PPB) at 4 and 6 kPa, respectively, with 14 respiratory parameters being measured. The results demonstrated that, when performing Q-G maneuver, the maximal expiratory flow rate averaged 1.175-1.645 L.s-1, the inspiratory peak flow, 1.003-1.297 L.s-1. Both these values were markedly lower than those of the L-1 maneuver, and matched well the performance of current aircraft oxygen apparatus. From the blood pressure and heart rate values, it is evident that PPB can further promote the blood pressure-raising effect of the Q-G maneuver, and alleviate pilots' fatigue.

Adult↗
PubMed1993

Noncholinergic airway constriction: role of axon reflex and oxygen radicals.

In the airways and lungs, activated afferent C-fibers release tachykinins, which induce noncholinergic bronchoconstriction. We have, for several years, focused our research on the role of axon reflex and oxygen radicals in noncholinergic airway constriction in guinea pigs. In this species, the noncholinergic bronchial constriction is not affected by administration of a ganglionic blocking agent, chlorisondamine, indicating that only the afferent C-fiber, not a complete reflex arc, is required for this constriction. Accordingly, we investigated the role of axon reflex by using tetrodotoxin (TTX) and bupivacaine to block impulse conduction in the axon. For the role of oxygen radicals, superoxide dismutase (SOD), catalase (CAT), and dimethylthiourea (DMTU) were employed to scavenge superoxide anion, hydrogen peroxide, and hydroxyl radical, respectively. We used capsaicin, resiniferatoxin (RTX), or hyperventilation to activate afferent C-fibers which, in turn, release tachykinins and lead to noncholinergic airway constriction. The constriction was quantified by measuring the maximal expiratory flow rate (Vmax) and dynamic compliance (Crs). Both capsaicin and RTX caused an immediate decrease in Vmax and Crs, indicating severe bronchoconstriction. This constriction decreased gradually with time. Tachykinin depletion abolished neurotoxin-induced airway constriction, suggesting that tachykinins mediate the constriction. Both TTX and bupivacaine significantly attenuated the constriction at 15-20 min after neurotoxin administration. Therefore, these data suggest that the axon reflex plays an important role in noncholinergic bronchial constriction. In other studies, capsaicin- or hyperventilation-induced bronchoconstriction was abolished by tachykinin depletion, as well as significantly ameliorated by the administration of antioxidants. These data indicate that oxygen radicals modulate the tachykinin-mediated noncholinergic airway constriction.

Animals↗
PubMed1993

Respiratory function in precapillary pulmonary hypertension.

Since dyspnoea on exertion is very often the first symptom of precapillary pulmonary hypertension (PPH), either from chronic thromboembolic pulmonary hypertension (CTEPH) or from idiopathic pulmonary hypertension (IPH), these patients are often first examined in a pulmonary function laboratory. We carried out a retrospective study (1987-1992) on pulmonary function in 34 patients diagnosed to have PPH by means of specific diagnostic tools, out of 5,467 patients first attending our laboratory. Nine suffered from IPH, 10 from CTEPH and 15 from Eisenmenger physiology. This last group differed from the others, since its diagnosis had been known for a long time and the stage of the disease was more advanced, when pulmonary function tests were performed in our laboratory (with a view to transplantation). Respiratory function, blood gases and arterial oxyhaemoglobin saturation (HbSaO2) during exercise (Bruce protocol), diffusing capacity of the lungs for carbon monoxide (DLCO), shunt fraction (QS%) (approximation obtained from arterial oxygen tension (PaO2) after 100% oxygen breathing) had been evaluated. In the first two groups, in contrast to other reports, we could observe no obstructive defect. Only 20% of the subjects had restrictive defects, however mild. The typical functional picture of these patients revealed normal lung volumes, normal or slightly reduced DLCO, mild hypoxaemia with hypocapnia, severe HbSaO2 drops during exercise, and pathological QS%. We conclude that every time a patient presents with breathlessness at rest or on exercise, a normal chest X-ray and respiratory function tests, pulmonary hypertension must be suspected and subject to specific and invasive tests. More severe functional impairment was observed in the PPH from the Eisenmenger disorder. This might be due to a more advanced stage of this type of hypertension at the time of our observation and/or to the different mechanisms of the diseases themselves.

Adult↗
PubMed1977

Ability of spirometry, flow-volume curves and the nitrogen closing volume test to detect smokers. A population study.

Vital capacity, FEV1 and various measurements of forced expiratory flows as well as closing volume (CV), closing capacity (CC), the mean slope of the alveolar plateau (phase III), the maximal amplitude of the cardiogenic oscillations (N2-osc), and other variables obtained from the nitrogen CV-test were measured in random samples of 50- (n = 221) and 60-year-old (n - 410) men in Gothenburg. All the variables were significantly different in smokers consuming 15 g or more tobacco daily compared with asymptomatic non-smokers. Reference values were established from measurements in the non-smokers without respiratory symptoms, and the sensitivities of the measured variables to tobacco smoking were assessed. Phase III revealed the highest sensitivity, being abnormal in about 40-60 % of subjects smoking 15 g or more tobacco daily and in about 30-35 % of subjects smoking less. CV and FEV1 were approximately equally sensitive, being abnormal in about 10-30 % of subjects smoking 15 g or more daily and in about 5-20 % in subjects smoking less. Other measurements of maximal expiratory flow rates gave values below minus two standard deviations for the appropriate reference group in less than 15 % of the smokers. However, when we took the skewed distribution of reference values into account we found a two- to sixfold increase of the sensitivities of these variables in the 50-year-old smokers, in which abnormal values were obtained in about 30-40 % of subjects smoking 15 g or more daily and in about 10-15 % in subjects smoking less. Taking all variables obtained from the CV-test in conjunction, one or more abnormal valves were obtained in 60-70 % of the subjects smoking 15 g or more daily. To the extent that sensitivity to smoking reflects sensitivity to abnormalities in small airways, phase III appeared to be the most efficient single measurement for detection of this condition in the present age groups.

Cough↗
PubMed1997

[Pneumoconiosis and exposure to wood].

The authors report a case of an employee in the wood processing industry. The clinical presentation was respiratory with dyspnoea on effort. The chest x-ray showed bilateral interstitial changes. Following bronchioalveolar lavage electron microscopic studies showed evidence of silica particles. Respiratory function tests showed pulmonary performance of 51%-64% of theoretical values depending on the test used. His working position involved the up keep of the boilers and also the drainage of the silos for wood dust. The wood used was corupixa, a brazilian wood containing crystalline silica; 0.1% in fresh wood dust. Numerous analyses have specified the percentage of silica in the ashes in magma. The diagnosis of pneumoconiosis of the silicotic type was sustained. The occupational risk linked to using this type of wood should be understood and the need to take protective measures for the employees concerned.

Adult↗
PubMed1997

[Ergospirometry].

Explore the source record for details and available documents.

Ergometry↗
PubMed1998

[Rolled atelectasis and asbestosis. Apropos of 26 patients].

Round atelectasis (AE) is a benign form of respiratory problem which develops due to fixing of the visceral pleura. This lesion for which the principal cause is exposure to asbestos may pose problems of differential diagnosis with bronchopulmonary cancer. In a cohort of 286 patients suffering from benign asbestos related pleural disease the diagnosis of round atelectasis was made on computerized tomography in 26 patients (31 AE) on the following criteria: rounded opacities of less than 7 cm in diameter situated at the periphery of the lung in contact with a thickened pleura with an acute angle linking the pleura and the opacity, a reduction of lung volume on the side of the atelectasis and the presence of a "comet tail sign". These patients were investigated to specify the circumstances of the occurrence, including their symptomatology, the changes in lung function, the topography of the round atelectasis and the associated radiological signs. Intense exposure to asbestos either continuous or discontinuous was found in 19 patients; 20 patients presented with some respiratory symptoms (dyspnoea 15/26, cough 11/26 and chest pain 9/26) but the reduction in lung function was moderate (7 had restrictive ventilatory trouble, 4 obstructive problems and a mixed problem in 1). The preferred localisation for round atelectasis was in the inferior lobes in the posterior basal lateral vertebral area (26/31) which may explain their being frequently missed on the standard radiograph (only one case of round atelectasis was visible on the straight chest radiograph in our study). An understanding of the pathology and the computered tomographic characteristics are now well defined and should enable an unnecessary diagnostic thoracotomy to be avoided which besides has no justification from the functional point of view.

Asbestosis↗