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PubMed1988

Lung function disturbances versus respiratory muscle fatigue in patients with systemic lupus erythematosus.

In 23 consecutive patients (mean age, 38.6 years) with systemic lupus erythematosus (SLE) and in 17 healthy subjects (mean age, 37.5 years) fatigue of respiratory (diaphragm, musculi intercostales externi) and leg muscles (musculus gastrocnemius) was determined comparatively by electromyography. Additionally, routine lung function parameters, including maximum inspiratory (PImax) and expiratory (PEmax) mouth pressures, were measured. The SLE patients showed lower values of vital capacity (VC), total lung capacity (TLC), thoracic gas volume (TGV), FEV1, PImax and PEmax than the healthy controls, while FEV1/VC, residual volume and specific airway conductance were not significantly different in either group. Lung compliance, corrected for TGV, was normal in the SLE group. Breathing through stenoses with increasing resistances resulted in fatigue of the diaphragm in 73% of the SLE group and in 41% of the control group. The corresponding values of the external intercostal muscles were 74% (SLE group) and 29% (control group). Electromyographic signs of respiratory and leg muscle fatigue occurred at lower loads in the SLE group than in the healthy subjects. The pattern of lung function data in patients with SLE was characteristic neither of lung restriction nor of airway obstruction. Respiratory muscle weakness can explain the decrease in TLC, VC, TGV, FEV1, PImax and PEmax.

Adult↗
PubMed2001

Inhalation toxicity of 1,6-hexamethylene diisocyanate homopolymers (HDI-IC and HDI-BT): results of subacute and subchronic repeated inhalation exposure studies.

This article addresses results of two 13-wk inhalation toxicity studies in Wistar rats with aerosolized 1,6-hexamethylene diisocyanate (HDI) homopolymers using either the isocyanurate (HDI-IC) type or biuret (HDI-BT) type. Groups of 10 rats/sex/level were exposed nose-only to breathing zone concentrations of 0.5, 3.3, and 26.4 mg HDI-IC/m(3) or 0.4, 3.4, and 21.0 mg HDI-BT/m(3) (MMAD = 1.4-3.3 microm). The exposure regimen was 6 h/day, 5 days/wk for 13 wk. Two control groups were used in each study; one was exposed to filtered air, and the other to the vehicle acetone. In subacute pilot studies, groups of rats were exposed under identical conditions for 3 consecutive weeks using concentrations of approximately 4, 15-18, and 77-90 mg homopolymer/m(3). All studies demonstrated that adverse effects were caused by irritation-related responses occurring predominantly in the lower respiratory tract. Following subchronic exposure, compound-related effects were found only at the highest concentrations used and were confined to mild respiratory distress, marginally decreased body weights, and increased lung weights. Hematological evaluation showed a marginal increase in leukocyte counts. Pulmonary function testing revealed minimal changes indicative of increases in functional residual capacity and total lung capacity but without evidence of increased bronchial hyperreactivity to acetylcholine aerosol. Histopathology demonstrated an increased recruitment of alveolar macrophages, focal interstitial fibrosis with round-cell infiltrations, and bronchiolo-alveolar proliferations at the high-level exposure groups. The no-observable-adverse-effect levels (NOAELs) of both the 3- and 13-wk studies were in the range of 3-4 mg/m(3). Appreciable differences between the two types of polyisocyanates were not observed.

Administration, Inhalation↗
PubMed2005

Morphometric deformations of small airways and alveoli under quasi-static inflation process.

Localized morphometric deformations of small airways and alveoli during respiration have many biomedical and physiological implications. We developed fast synchrotron radiation CT system to visualize the small airways and alveoli of an intact mouse lung without fixation and dehydration, and analyzed their localized morphometric deformations between functional residual capacity (FRC) and total lung capacity (TLC). In the diameter behavior, the averaged and range values were significantly larger for smaller airways (68.8%, range: 0.36-0.89) than larger airways (45.2%, range: 0.40-0.57). These results indicated that the airway did not deformed in same manner and that these morphological differences characterized the heterogeneous lung function.

Air Pressure↗
PubMed1997

Aerosol bolus dispersion in healthy subjects.

Aerosol bolus dispersion is a physiological test of lungs, which uses monodisperse submicron particles to measure intrapulmonary convective gas mixing. In this study, aerosol bolus dispersion was measured in healthy subjects in order to assess reference values for possible clinical applications, to assess the reproducibility of these values, and to identify physical and physiological factors influencing aerosol bolus dispersion. Aerosol bolus dispersion was measured in 79 healthy subjects using 20 cm3 aerosol boluses consisting of monodisperse di-2-ethylhexyl sebacate (DEHS) particles. The reproducibility of parameters characterizing the width of the exhaled bolus was of the same order as that of parameters of the flow-volume curve (10%). Aerosol bolus dispersion was independent of the level of lung inflation, and the slope of the relationship between flow rate and dispersion was on average not significantly different from zero (range 100-700 cm3.s-1). Multiple linear regression showed that aerosol bolus dispersion increased with increasing total lung capacity of the subject. We conclude that differences in total lung capacity between individuals should be taken into account when using measures of aerosol bolus dispersion for possible clinical applications.

Administration, Inhalation↗
PubMed1993

Pulmonary function changes after large volume paracentesis.

Large volume paracentesis (LVP) is a safe, rapid, and effective treatment of ascites in cirrhotic patients. We investigated the effects of a 5-L aspiration of ascites on pulmonary function parameters in eight hemodynamically stable patients with cirrhosis and tense ascites. None had known lung disease or abnormal chest roentgenograms. At baseline, mean lung volumes, diffusing capacity, and arterial pO2 were all reduced from normal predicted values. Airflow, however, when related to lung volume, was normal. Post-LVP, lung volumes increased significantly; the mean expiratory reserve volume showed the greatest percent increase (105%) and correlated with the increases in the vital capacity, functional residual capacity, and total lung capacity. Airflow, the mean diffusing capacity, and arterial oxygenation were not significantly changed after LVP. We conclude that LVP significantly increases indices of lung volume but does not significantly alter parameters of airflow or gas exchange.

Ascites↗
PubMed1993

Differences in CT density between dependent and nondependent portions of the lung: influence of lung volume.

OBJECTIVE: Lung tissue, blood, and air determine the physical density of the lung and hence the attenuation measured on CT scans. These components are not homogeneously distributed throughout the lungs, and their relative proportion changes continuously during respiration. The objective of this study was to measure densities in various areas of the normal lung with CT and to examine the influences of gravity and of the degree of lung inflation on these densities. SUBJECTS AND METHODS: The subjects in the study were six healthy male volunteers. CT scans were obtained at the level of the aortic arch and 2 cm above the expiratory level of the diaphragm with the subjects supine and then with them prone. Scans were obtained at lung volumes of 10%, 50%, and 90% vital capacity by using a respiratory gating device connected to the CT scanner. The overall density of the lungs at these two levels and the densities in the dependent (posterior in supine, and anterior in prone body position) and nondependent (anterior in supine and posterior in prone body position) areas were measured by using a semiautomatic evaluation algorithm. RESULTS: Changes in lung volume caused the same changes in lung density in the right and left lungs and in the upper and lower parts of the lungs. For both body positions (supine and prone), the difference between lung density at 10% vital capacity and that at 90% vital capacity was significantly larger (p < .05) in the dependent parts of the lung than in the nondependent parts. In both positions, differences in density between dependent and nondependent regions were significantly (p < .05) greater at 10% vital capacity than at 90% vital capacity, and the differences became small when the volume of the lung was near total lung capacity. CONCLUSION: Changes in lung volume have different effects on changes in lung density in dependent and nondependent parts of the lung. The largest changes in lung density occur in the dependent regions. The difference in density between dependent and nondependent lung regions is smallest for lung volumes near total lung capacity. These findings may be useful as a baseline for interpreting CT measurements of regional lung density in suspected cases of lung disease, which would alter the physical density of lung tissue. Our results also suggest that measurements near total lung capacity should be included.

Adult↗
PubMed1978

Closing volume during normal pregnancy.

Serial lung function studies were performed in ten healthy, primiparous women aged 21--28. Measurements were made at two-monthly intervals during pregnancy and included functional residual capacity (FRC), total lung capacity (TLC), vital capacity (VC), specific conductance (SGaw) and closing volume (CV) on each occasion. Closing volume expressed as formular: (see text), showed a progressive rise during pregnancy in all subjects with a linear relationship to time (P less than 0.001, P greater than 0.01, respectively). No consistent changes in lung volume could be shown during pregnancy over the study period. It is suggested that the increase in closing volume during pregnancy might result in abnormalities of distribution of ventilation sufficient to explain the maternal blood gas disturbances of pregnancy.

Adult↗
PubMed2006

Simulated obesity-related changes in lung volume increases airway responsiveness in lean, nonasthmatic subjects.

STUDY OBJECTIVE: To determine if obesity-related changes in lung volume might contribute to airway reactivity, we investigated the effects of simulated mild obesity-related lung volume reductions on airway responsiveness in lean, nonasthmatic subjects. PARTICIPANTS AND METHODS: We simulated the lung volume reductions of class 1 obesity in eight lean, nonasthmatic subjects by externally mass loading the chest wall and abdomen, and shifting blood volume into the lung with lower limb compression (LLC). Airway responsiveness was assessed by measuring FEV(1) before and after methacholine challenge tests (1, 2.5, 5, 10, and 25 mg/mL) with the following: (1) no intervention (control); (2) external chest loading (CL); (3) LLC; and (4) CL and LLC (COMB) on separate days. Lung function was measured before and after CL, LLC, and COMB were applied. RESULTS: The application of CL, LLC, and COMB decreased expiratory reserve volume, functional residual capacity, and total lung capacity compared with baseline. FVC and FEV(1) decreased significantly with CL and COMB, while FEV(1)/FVC did not change compared to baseline. The maximal response to the methacholine challenge increased with CL, LLC, and COMB, with a mean maximal fall of FEV(1) of 9%, 11%, and 18%, respectively, compared to a 6% fall with control. CONCLUSIONS: We conclude that decreases in lung volume increase airway responsiveness and may account for the increased propensity for increased airway responsiveness in the obese.

Administration, Inhalation↗
PubMed1986

Pulmonary toxicity induced by mitomycin C is highly responsive to glucocorticoids.

The authors have studied five cases of biopsy-proven pulmonary toxicity caused by the administration of mitomycin C (M), vincristine, and cisplatin in 64 patients with advanced non-small cell lung cancer. The clinical triad of progressive dyspnea, rales, and pulmonary infiltrates presented in all five cases. In addition, pulmonary function tests showed hypoxemia (four/five), reduced forced vital capacity (three/four), total lung capacity (two/three), and forced expiratory volume (FEV1) (three/four) and very profound reduction in diffusion capacity (three/three). Transbronchial biopsy for tissue examination was necessary to rule out other causes. Characteristics but nonspecific pathologic changes were documented in all five cases. All the patients responded quickly and dramatically to high-dose glucocorticoids with improvement of hypoxia, dyspnea, exercise tolerance, and sense of well being. In three patients the pulmonary infiltrates cleared. However, abrupt stopping or early withdrawal of steroid resulted in aggravation of dyspnea and pulmonary infiltrate in three cases who improved subsequently with escalation of steroid doses. The authors conclude that the treatment of choice for pulmonary toxicity induced by M or M-containing chemotherapy regimens is a high dose of glucocorticoid and discontinuation of M at once when suspicion is raised.

Female↗
PubMed2006

Computed tomography and pulmonary function abnormalities in sickle cell disease.

The aim of this study was to determine whether patients with sickle cell disease (SCD) in steady state had pulmonary abnormalities seen on high-resolution computed tomography (HRCT) and whether any abnormalities correlated with contemporaneously diagnosed lung function abnormalities. A subsidiary question was whether the results of a noninvasive measure of haemolysis (end-tidal carbon monoxide (ETCO) levels) correlated with pulmonary function abnormalities. Thirty three patients with SCD, median (range) age 36 yrs (17-67 yrs) were examined. The degree of lobar volume loss and ground-glass opacification and prominence of central vessels on HRCT were quantitatively assessed. Pulmonary function was assessed by measurements of lung volumes, spirometry, gas transfer and oxygen saturation. ETCO levels were measured using an end-tidal CO monitor. Forced expiratory volume in one second (FEV1), forced vital capacity and total lung capacity significantly correlated with HRCT findings, particularly lobar volume loss. ETCO levels significantly negatively correlated with FEV1, vital capacity measured using a plethysmograph, specific airway conductance and arterial oxygen saturation measured by pulse oxymetry. In conclusion, the present results suggest that high-resolution computed tomography noninvasive assessment of haemolysis might be useful to identify sickle cell disease patients with respiratory function impairment.

Adolescent↗
PubMed2002

[Hypodynamic respiratory insufficiency. Diagnostic investigation].

Patients with restrictive lung disease, owing to respiratory muscle dysfunction, have no parenchymal involvement. Their vital capacity (VC) and total lung capacity (TLC) are reduced to less than 50% and can lead to pneumonia and nocturnal hypercapnia and hypoxia. Their diffusion capacity is normal. With maximal static mouth pressure (Pimax) < 80 cm H2O and/or Pemax < 100 cm H2O, patients are referred to the national centres. Here, inspiratory muscular insufficiency is confirmed by sniff nasal inspiratory pressure and oesophageal pressure < 70 cm H2O. Expiratory muscular insufficiency is confirmed by a cough peak flow < 3-4 L/sec. and cough gastric pressure < 100 cm H2O. Sleep studies reveal nocturnal hypoventilation. Phrenic nerve stimulation is to be introduced in the diagnostic approach. Twitch mouth or oesophageal pressure < 10 cm H2O and twitch gastric pressure < 7 cm H2O are pathognomonic for neuromuscular respiratory insufficiency.

Female↗
PubMed2004

Inspiratory muscle training improves lung function and exercise capacity in adults with cystic fibrosis.

STUDY OBJECTIVES: To investigate the effects of high-intensity inspiratory muscle training (IMT) on inspiratory muscle function (IMF), diaphragm thickness, lung function, physical work capacity (PWC), and psychosocial status in patients with cystic fibrosis (CF). DESIGN: Twenty-nine adult patients with CF were randomly assigned to three groups. Two groups were required to complete an 8-week program of IMT in which the training intensity was set at either 80% of maximal effort (group 1; 9 patients) or 20% of maximal effort (group 2; 10 patients). A third group of patients did not participate in any form of training and acted as a control group (group 3; 10 patients). INTERVENTIONS: In all patients, baseline and postintervention measures of IMF were determined by maximal inspiratory pressure (Pimax), and sustained Pimax (SPimax); pulmonary function, body composition, and physical activity status were also determined. In addition, diaphragm thickness was measured at functional residual capacity (FRC) and total lung capacity (TLC) [TDIcont], and the diaphragm thickening ratio (TR) was calculated (TR = thickness during Pimax at FRC/mean thickness at FRC). Subjects also completed an incremental cycle ergometer test to exhaustion and two symptom-related questionnaires, prior to and following training. RESULTS: Following training, significant increases in Pimax and SPimax (p < 0.05), TDIcont (p < 0.05), TR (p < 0.05), vital capacity (p < 0.05), TLC (p < 0.05), and PWC (p < 0.05) were identified, and decreases in anxiety scores (p < 0.05) and depression scores (p < 0.01) were noted in group 1 patients compared to group 3 patients. Group 2 patients significantly improved Pimax and SPimax (both p < 0.05) only with respect to group 3 patients. No significant differences were observed in group 3 patients. CONCLUSION: An 8-week program of high-intensity IMT resulted in significant benefits for CF patients, which included increased IMF and thickness of the diaphragm (during contraction), improved lung volumes, increased PWC, and improved psychosocial status.

Adult↗
PubMed1997

Relationship between cutaneous and pulmonary involvement in systemic sclerosis.

OBJECTIVE: Pulmonary disease may shorten survival in patients affected by systemic sclerosis (SSc). However, pulmonary involvement may commonly be silent, whereas skin fibrosis is usually the clinical feature drawing most attention. We investigated the relationship between cutaneous and pulmonary involvement during SSc. METHODS: We studied 52 patients (mean age 50.2 +/- 13.7 years) affected by SSc (mean duration of disease 13.8 +/- 9.5 years). Twenty-eight had the diffuse form of the disease (dSSc) and 24 the limited form (lSSc). All patients underwent pulmonary function studies, high resolution computed tomography (HRCT) of the lungs, and complete echocardiographic examination. Pulmonary artery systolic pressure was measured by Doppler echocardiography. Pulmonary interstitial fibrosis and skin fibrosis were evaluated using a point system. RESULTS: Mean percentages of predicted values of forced vital capacity and total lung capacity were significantly reduced in patients with dSSc compared to lSSc (80.0 +/- 18.9 vs 98.4 +/- 16.8%, p < 0.001; and 81.3 +/- 13.9 vs 92.1 +/- 14.2%, p < 0.01, respectively). The overall HRCT score was 6.1 +/- 4.9, with no significant differences between disease subgroups. However, a HRCT score of 10 or more was present in 10 patients with dSSc vs 2 patients with lSSc (p = 0.02). Pulmonary hypertension was present in 27 patients, 15 with lSSC and 12 with dSSc (p = NS). No significant correlation was observed between skin score and lung volumes, carbon monoxide diffusing capacity, HRCT score, or pulmonary artery systolic pressure for all patients and subgroups. CONCLUSION: Extent and severity of cutaneous and pulmonary involvement in SSc are not directly correlated. Nevertheless, different patterns of pulmonary involvement between SSc subgroups were observed. Restrictive lung disease was more frequent in patients with dSSc, while a trend to higher prevalence of pulmonary hypertension was observed in patients with lSSc.

Adult↗
PubMed1986

Effect of short and long term antibiotic response on lung function in bronchiectasis.

In a study designed to show whether purulent bronchial secretions damage the lung reversibly or irreversibly, 18 patients with bronchiectasis underwent lung function tests before and after two weeks' antibiotic treatment to convert their sputum from purulent to mucoid, and 10 of them also after four months' treatment. After two weeks FEV1, forced vital capacity, vital capacity, functional residual capacity, and total lung capacity showed small but statistically significant (though not clinically useful) improvements. In the 10 patients studied after four months only FVC (of the four indices with significant improvements at two weeks in this group) was still higher than before treatment. These results contrast with those of an earlier study, in which large acute changes were found, perhaps because of differences in the patients studied. It is concluded that the absence of major changes in lung function points to physiological abnormality that is largely irreversible in these patients with chronic bronchial sepsis.

Adult↗
PubMed2006

The effects of body mass index on lung volumes.

BACKGROUND: Obesity is a major health issue in North America, and the trend is for obesity to be a more important medical issue in the future. Since obesity can cause respiratory symptoms, many obese people are referred for pulmonary function tests (PFTs). It is well known that obesity causes decreases in lung volumes, but there has never been a large study showing the correlation between body mass index (BMI) and the various lung volumes. DESIGN: We collected PFT results from 373 patients sent for lung function testing who had normal values for airway function but a wide range of BMIs. SETTING: The PFTs were done in two accredited outpatient laboratories. RESULTS: There were significant linear relationships between BMI and vital capacity and total lung capacity, but the group mean values remained within the normal ranges even for morbidly obese patients. However, functional residual capacity (FRC) and expiratory reserve volume (ERV) decreased exponentially with increasing BMI, such that morbid obesity resulted in patients breathing near their residual volume. An important finding was that the greatest rates of change in FRC and ERV occurred in the overweight condition and in mild obesity. At a BMI of 30 kg/m2, FRC and ERV were only 75% and 47%, respectively, of the values for a lean person with a BMI of 20 kg/m2. CONCLUSIONS: We showed that BMI has significant effects on all of the lung volumes, and the greatest effects were on FRC and ERV, which occurred at BMI values < 30 kg/m2. Our results will assist clinicians when interpreting PFT results in patients with normal airway function.

Adult↗
PubMed1978

Reversible pulmonary oxygen toxicity in the primate.

In order to investigate the effects of high concentrations of oxygen on the lung, experiments were performed on 18 baboons exposed to a humidified environment of 95% oxygen for five days. Open lung biopsies for biochemical assay, histologic and electron microscopic analysis and measurement of tissue respiration were performed before and after oxygen exposure. Pulmonary function was evaluated by measurement of arterial blood gases, compliance, closing capacity (CC), functional residual capacity (FRC), total lung capacity (TLC), residual volume (RV) and vital capacity (VC) before and after exposure and then at seven and 14 days in the animals which recovered. Six baboons removed from the oxygen environment after 96--110 hours and exposed to room air died within three to 20 hours of profound hypoxemia (PaO2 40 +/- 6). The remaining 12 baboons were successfully weaned to room air over a three day period with a return of ABGs to control values (PaO2 89+/- 2). Electron microscopic analysis of alveolar membranes exposed to 120 hours of hyperoxia demonstrated endothelial cell swelling, interstitial alveolar membrane edema, and an increased predominance of Type II pneumocytes. Lung volume measurements showed significant decreases in TLC (25%), VC (34%), CC/TLC (28%) and dynamic compliance (47%). Biochemical studies indicated a shift toward anaerobic metabolism with a decrese in tissue oxygen consumption, reduced cytochrome oxidase activity, and increased lung lactic acid production. These changes were all found to be reversible in the 12 baboons slowly weaned back to room air.

Animals↗
PubMed1995

Heart-lung interactions determined by electron beam X-ray CT in laterally recumbent rabbits.

Electron beam X-ray computed tomography (CT) was used to measure lung air content and its distribution within the lung as well as lung shape and heart position in rabbits in right and left lateral recumbency. Sham-operated control (S) rabbits and left-pneumonectomized rabbits with wax plombage were studied at functional residual capacity (FRC) and total lung capacity. Results were obtained for both lungs and for the right lung only of S rabbits. FRC of both lungs and the right lung only of the S rabbits and of the remaining right lung of the pneumonectomized rabbits was smaller in rabbits in right lateral recumbency than in those in left lateral recumbency. The reduction in right lung volume at FRC was accompanied by an overall reduction in lung size, although the lung shape remained similar, and was accompanied by movement of the heart centroid toward the dependent chest and spine. Application of a positive tracheal pressure of 25 cmH2O increased lung volume and reduced the dependency of lung volume and shape on posture. Lung inflation in the right lateral position was accompanied by movement of the heart centroid away from the dependent chest and spine. Gravitational gradients in regional air content did not differ between the cranial half of the lung, which was in contact with the heart, and the caudal half of the right lung, which was not in contact with the heart. Likewise, the cephalocaudal gradient in regional air content was similar when the right lung was dependent and nondependent. The location of the heart in the cranial half of the thorax does not appear to induce differences in regional air content between the cranial and caudal lung halves.

Animals↗
PubMed1978

Long-term effect of previous swimtraining in girls. A 10-year follow-up of the "girl swimmers".

Thirty girls, studied in 1961 after 2.5 years of intensive swimtraining, were the subject of a follow-up for ten years. When last examined, seven and ten years after the original study, all the girls had given up swimtraining. The increased values for vital capacity observed in 1961 remained unchanged, but residual volume, functional residual capacity and total lung capacity showed small increases even after corrections for body growth. Such increases are, however, normal in these years. Heart volume which was high originally, was found to be lower ten years later, although mean values were still higher than normal. The decreases seen from 1961 to 1971 could mainly be ascirbed to a decrease in the subjects with the larges hearts originally. Both total hemoglobin and blood volume decreased to normal values in relation to body size. Maximal oxygen uptake, though, fell from 2.80 l/min (51. 4 ml/kg X min) to 2.18 l/min (36.4 ml/kg X min) ten years later. It is suggested that the functional capacity of the cardiovascular system declined more markedly than its dimensions.

Adolescent↗