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PubMed1994

Abnormal pattern of lung functions in rubber factory workers.

The influence of suspended particulate matter, benzo(e) pyrene, benzo(e) pyrene and benzo(a) anthracene concentration on pulmonary lung functions ie, residual volume, total lung capacity, residual volume/total lung capacity, forced residual capacity were studied in 667 rubber factory workers during 1990-91. The respirable fraction of the particulate size (< 0.5 micron) showed high mean concentration of suspended particulate matter, benzo(a) pyrene, benzo(e) pyrene and benzo(a) anthracene in the compounding section (group III), when compared with vulcanising (group II) and packing loading (group I) units. While comparing the lung functions amongst these groups, the higher results of residual volume, residual volume/total lung capacity ratio, forced respiratory capacity and lower values of total lung capacity were observed in group III workers as compared with other two groups. And also these results seem to be correlated with the high pollutant concentrations to which group III workers were exposed, and reflect a clear combination of obstructive and restrictive pattern of lung functions in them.

Air Pollutants, Occupational↗
PubMed1981

Intrasubject variability of pulmonary function testing in healthy children.

The intrasubject variability of repeat pulmonary function testing was examined in 20 healthy children aged 10 to 16 years. The children were tested a maximum of 11 times over a period of two months. The tests examined were spirometry, maximum expiratory flow-volume curves, body plethysmograph determination of lung volumes, and single breath nitrogen washout. The time of day or the length of the re-test interval, up to a period of two months, did not significantly affect the variability. Standard deviation was used when comparing the variability of measurements with the same units and coefficient of variation was used when comparing measurements of different units. The vital capacity measured by spirometry was the least variable measurement. Functional residual capacity, residual volume and total lung capacity were equally reproducible but as a group were more variable than vital capacity. There was no significant difference between the variability of the following measurements: forced expired flow from 25 to 75% of the vital capacity, flows at 70%, 50% and 40% total lung capacity, and flows at 50% vital capacity. Flows at 25% vital capacity were significantly less variable than other measurements of flow. The variability of forced expired volume in one second was examined and the use of this measurement in determining significant bronchial hyper-reactivity was assessed.

Adolescent↗
PubMed1998

Effects of lung volume on diaphragm EMG signal strength during voluntary contractions.

The use of esophageal recordings of the diaphragm electromyogram (EMG) signal strength to evaluate diaphragm activation during voluntary contractions in humans has recently been criticized because of a possible artifact created by changes in lung volume. Therefore, the first aim of this study was to evaluate whether there is an artifactual influence of lung volume on the strength of the diaphragm EMG during voluntary contractions. The second aim was to measure the required changes in activation for changes in lung volume at a given tension, i.e., the volume-activation relationship of the diaphragm. Healthy subjects (n = 6) performed contractions of the diaphragm at different transdiaphragmatic pressure (Pdi) targets (range 20-160 cmH2O) while maintaining chest wall configuration constant at different lung volumes. The diaphragm EMG was recorded with a multiple-array esophageal electrode, with control of signal contamination and electrode positioning. The effects of lung volume on the EMG were studied by comparing the crural diaphragm EMG root mean square (RMS), an index of crural diaphragm activation, with an index of global diaphragm activation obtained by normalizing Pdi to the maximum Pdi at the given muscle length (Pdi/Pdimax@L) at the different lung volumes. We observed a direct relationship between RMS and Pdi/Pdimax@L independent of diaphragm length. The volume-activation relationship of the diaphragm was equally affected by changes in lung volume as the volume-Pdi relationship (60% change from functional residual capacity to total lung capacity). We conclude that the RMS of the diaphragm EMG is not artifactually influenced by lung volume and can be used as a reliable index of diaphragm activation. The volume-activation relationship can be used to infer changes in the length-tension relationship of the diaphragm at submaximal activation/contraction levels.

Adult↗
PubMed1987

Early-onset diagnosis of lung toxicity caused by cyclophosphamide, melphalan and procarbazine therapy.

Lung function studies were performed in 33 patients with lymphomyeloproliferative diseases (25 cases of multiple myeloma and 8 cases of Hodgkin's disease) who received cyclophosphamide, procarbazine, and melphalan therapy. Lung function was investigated by spirometric tests, indicative tests of small airways disease, and diffusing capacity of the lung for carbon monoxide (DUCO). Indicative tests of small airways disease and other lung function tests such as forced expiratory volume in 1 second (FEV1), vital capacity (VC), total lung capacity (TLC) etc. were markedly improved in 18 patients (55%), whereas 24 patients (73%) showed a decreased diffusing capacity of the lung for carbon monoxide. Furthermore, most of the patients (77%-83%) showed contemporaneous involvement of spirometric tests and DUCO. The DUCO was also found more constantly impaired than other function tests because it had decreased with and without other spirometric tests. Impaired lung function tests were found to be related to a cumulative dose of antineoplastic drugs. The absence of increased lung toxicity was found to be related to several drugs administered in combination. In view of the absence of previous bronchopathies, lung involvement signs in multiple myeloma (25, 26) or lymphoma, and concomitant bronchopneumonias, the impaired functional tests could be ascibed to drug-induced lung toxicity. In the absence of clinical symptoms, roentgenographic and pathologic features, impaired lung function tests may play a role as early-onset signs of drug-induced lung toxicity.

Adult↗
PubMed1976

Determination of lung volume by single- and multiple-breath nitrogen washout.

In 10 normal volunteers, total lung capacity determined from a single-breath N2 washout was not significantly different from that determined by body plethysmography. However, in patients who underwent clinical pulmonary function tests, total lung capacity was substantially underestimated by the single-breath N2 washout, compared with that determined by either body plethysmography or the 7-min open-circuit N2 washout method. The single-breath N2 washout underestimated total lung capcity in patients who had a normal slope of Phase III, and the error was even greater in patients who had steeper Phase III slopes or low maximal mid-expiratory flow values. Total lung capacity determined by 5 vital capacity breath N2 washout method was comparable to that determined by the 7-min N2 washout method, provided that expired N2 did not exceed 10 per cent during the fifth vital capcity maneuver. By extending the washout beyond 5 vital capacity maneuvers when necessary to achieve a peak expired N2 of less than 10 per cent, a mean total lung capacity within 1 per cent of that determined by the 7-min washout method was obtained. The multiple vital capacity maneuver was well tolerated by patients and saved considerable time.

Humans↗
PubMed1988

Lung volume standards for healthy male lifetime nonsmokers.

Functional residual capacity (FRC), residual volume (RV), vital capacity (VC), and total lung capacity (TLC) were measured in 162 men aged 18.9 to 78.6 years using a multiple breath helium dilution technique. Multiple regression equations were generated to predict these lung parameters from the best weighted combination (p less than or equal to 0.05) of age, mass, standing height, body surface area, sitting height, biacromial breadth, end-tidal chest girth, expanded chest girth, and chest expansion (FRC: R = .748, SEE = 504 ml; RV: R = .725, SEE = 301 ml; VC: R = .808, SEE = 537 ml; TLC: R = .808, SEE = 551 ml; RV/TLC: R = .778, SEE = 4.15 percent). The range of normality was defined as the predicted value +/- the 95 percent confidence interval (two-tailed test). Cross-validation of other FRC, RV, VC, and TLC equations in the literature indicated that they were unsuitable for use with our data.

Adolescent↗
PubMed1981

Serial observations of angiotensin-converting enzyme and pulmonary function in sarcoidosis.

Fifty-six measurements of angiotensin-converting enzyme (ACE) level, diffusing capacity (DLCO), and total lung capacity (TLC) were made in 18 sarcoid patients with a maximum of 25 months of follow-up observation. During spontaneous or corticosteroid-induced changes in disease activity, there was a significant inverse correlation between changes in ACE level and changes in DLCO and between changes in ACE level and changes in TLC. These observations suggest that ACE measurement may be a useful adjunct to pulmonary function tests to follow the course of sarcoidosis and to monitor the effects of corticosteroid therapy on the lung.

Adrenal Cortex Hormones↗
PubMed1981

[Pulmonary volume and cardiopulmonary function in acute myocardial infarction (author's transl)].

In order to evaluate alterations in lung mechanisms detected in patients with acute myocardial infarction (MI), changes in arterial oxygenation and pulmonary volume in relation to the hemodynamic status were measured in 19 patients with acute MI. Pulmonary volume was determined with spirometry and helium dilution closed technic at 24 and 72 hours and two months after acute MI. The first finding was decreased arterial PO2: 328 +/- 29 mm/Hg (mean +/- SE) which had significantly risen by the third day: 423 +/- 20 mm/Hg (p less than 0.02). This disturbance was accompanied by an increased pulmonary shunt (Qs/Qt) and VD/VT relation, which improved with time but did not return to normal. A manifest relationship was not found between the degree of hypoxemia and diminished functional residual capacity (FRC). During the acute phase lung volume was normal while patients were seated but upon assuming a supine position, vital capacity (VC), total lung capacity (TLC) and RV/TLC were altered considerably. The VC and RV/TLC alterations were significantly altered in patients with left ventricular dysfunction. No significant changes were found in pulmonary values during the acute phase and VC and TV/TLC had improved considerably two months later. It is probable that increased interstitial pulmonary edema bears the main responsibility for these alterations, including in uncomplicated acute MI.

Adult↗
PubMed1983

Noninvasive quantitative imaging of shape and volume of lungs.

The Dynamic Spatial Reconstructor (DSR) can be used to determine detailed structure-to-function relationships or organ systems in vivo. A basic index of lung structure (shape and dimensions) is total lung volume. We checked the accuracy with which in vivo lung volumes can be measured by comparing lung volume (air plus tissue) determined by DSR scanning with that determined by excision and water displacement. Six dogs (2.5-26 kg) under morphine-pentobarbital anesthesia were scanned supine or prone at functional residual capacity and/or total lung capacity. With the trachea clamped at the lung volume scanned, a lethal dose of pentobarbital was administered, the lung excised, and its volume determined by water displacement. In vivo scan data were used to reconstruct adjacent 0.9-mm-thick transverse sections over the entire axial extent of the thorax. A three-dimensional surface-detection algorithm was used to generate shaded surface displays of the in situ lungs. The number of voxels (volume picture elements) of known dimensions contained within the three-dimensional image of the lung was summed to estimate total lung volume. Lung volumes calculated from the in vivo images ranged from -3.4 to +2.3% of the lung volume determined in vitro. The mean difference was 1.38 +/- 0.07% (SE). Regression analysis yielded an r value (correlation) of 1.00, a slope of 0.99, and an intercept of -4.35 ml. Multiple lung inflation steps scanned and analyzed in one dog showed similar accuracy. This technique is applicable to subjects with thorax dimensions up to 42 cm in cephalocaudal height and 39 cm in ventrodorsal and transverse diameters.

Animals↗
PubMed1994

Intratracheal antioxidants attenuate exsanguination-induced bronchoconstriction in guinea pigs.

The role of oxygen radicals in exsanguination-induced bronchoconstriction (EIB) was investigated using intratracheal instillation of antioxidants. In series 1, 49 guinea pigs (331 +/- 6 g) were employed in the functional study. These animals were divided into seven groups: control, superoxide dismutase (SOD), catalase (CAT), erythrocytes (RBCs), N-[2-(2-oxo-1-imidazolindinyl)-ethyl]-N'-phenylurea (EDU), ruthenium red (RR), and systemic capsaicin pretreatment. SOD, CAT, RBCs, and EDU are antioxidants, whereas RR is a blocker of transmembrane Ca2+ fluxes. All agents except capsaicin were administered by intratracheal instillation 30 min before exsanguination; each animal of the last group received a 5-day subcutaneous capsaicin pretreatment. All animals were anesthetized, sternotomized, and exsanguinated. Before as well as 1-30 min after exsanguination, the maximal expiratory flow maneuver was performed and the minimal volume was obtained. In the control group, exsanguination caused gradual decreases in the maximal expiratory flow at 50% baseline total lung capacity, forced expiratory volume at 0.1 s, and total lung capacity as well as a gradual increase in the minimal volume, indicating that EIB becomes more severe with time. EIB was significantly ameliorated by intratracheal instillation of SOD, CAT, RBCs, EDU, and RR, and it was almost abolished by systemic capsaicin pretreatment. In series 2, however, inactivated CAT did not significantly affect EIB. We determined tracheal neutral endopeptidase (NEP) activity in 23 animals. Thirty minutes after exsanguination, there was a significant decrease in NEP activity in the control but not the CAT group. These results indicate that EIB is modulated by oxygen radicals, which inactivate NEP.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

Effect of lung volume on pulmonary mechanics in guinea pigs.

The lung volume (VL) dependence of several dynamic pulmonary mechanical properties of the guinea pig lung were determined over the range of the vital capacity (10-100% VC) with the vagi intact and sectioned. We found dynamic compliance to be strongly VL dependent, decreasing as much as 85% between functional residual capacity (FRC) and total lung capacity (TLC). Below FRC, dynamic compliance either remained unchanged or decreased, depending upon the technique used in its measurement. Pulmonary resistance (RL) decreased monotonically with increasing VL, whereas pulmonary conductance was linearly related to VL. Conductance was much less sensitive to VL than compliance, increasing only 28% between FRC and TLC. The sensitivity of pulmonary conductance to VL was substantially increased by subtracting the resistance of the tracheal cannula from RL. Specific pulmonary conductance was not independent of VL but decreased approximately 45% over the range of the VC. Pulmonary inertance was found to be unaffected by VL. Extrapolation from these data indicate that small differences in FRC, which might be expected within and between studies relying on pulmonary mechanical measurements, would most strongly affect compliance estimates and only moderately alter resistance estimates. It also indicates that the use of specific pulmonary conductance does not remove VL as an independent variable.

Airway Resistance↗
PubMed1987

Pulmonary follow-up of moderately low birth weight infants with and without respiratory distress syndrome.

Pulmonary function was measured in 18 children aged 6 to 9 years who had been born prematurely (mean birth weight 1760 +/- 555 g) and who had each received greater than 100 hours (mean 177 +/- 74 hours) of mechanical ventilation for respiratory distress syndrome (RDS). We used as controls 26 children aged 6 to 7 years who had been born prematurely (mean birth weight 1636 +/- 554 g) but who had required no treatment for pulmonary disease. Results for total lung capacity, FEV1, ratios of functional residual capacity and residual volume to total lung capacity, specific airway conductance, and alveolar plateau slope did not differ in the RDS and control groups. Eight of the 18 children in the RDS group had had radiologic evidence of bronchopulmonary dysplasia at 30 days and oxygen dependence at 30 days, but did not differ from the control group for any of the indices of pulmonary function. However, FEV1 and specific airway conductance were significantly reduced in the premature control group compared with children born at term. Therefore, factors associated with prematurity rather than combined effects of RDS and its treatment determined pulmonary function at age 6 to 9 years.

Airway Obstruction↗
PubMed1996

Breathing pattern and carbon dioxide retention in severe chronic obstructive pulmonary disease.

BACKGROUND: The factors leading to chronic hypercapnia and rapid shallow breathing in patients with severe chronic obstructive pulmonary disease (COPD) are not completely understood. In this study the interrelations between chronic carbon dioxide retention, breathing pattern, dyspnoea, and the pressure required for breathing relative to inspiratory muscle strength in stable COPD patients with severe airflow obstruction were studied. METHODS: Thirty patients with COPD in a clinically stable condition with forced expiratory volume in one second (FEV1) of < 1 litre were studied. In each patient the following parameters were assessed: (1) dyspnoea scale rating, (2) inspiratory muscle strength by measuring minimal pleural pressure (PPLmin), and (3) tidal volume (VT), flow, pleural pressure swing (PPLsw), total lung resistance (RL), dynamic lung elastance (ELdyn), and positive end expiratory alveolar pressure (PEEPi) during resting breathing. RESULTS: Arterial carbon dioxide tension (PaCO2) related directly to RL/PPLmin, and ELdyn/PPLmin, and inversely to VT and PPLmin. There was no relationship between PaCO2 and functional residual capacity (FRC), total lung capacity (TLC), or minute ventilation. PEEPi was similar in eucapnic and hypercapnic patients. Expressing PaCO2 as a combined function of VT and PPLmin (stepwise multiple regression analysis) explained 71% of the variance in PaCO2. Tidal volume was directly related to inspiratory time (TI), and TI was inversely related to the pressure required for breathing relative to inspiratory muscle strength (PPLsw, %PPLmin). There was an association between the severity of dyspnoea and both the increase in PPLsw (%PPLmin) and the shortening in TI. CONCLUSIONS: The results indicate that, in stable patients with COPD with severe airflow obstruction, hypercapnia is associated with shallow breathing and inspiratory muscle weakness, and rapid and shallow breathing appears to be linked to both a marked increase in the pressure required for breathing relative to inspiratory muscle strength and to the severity of the breathlessness.

Aged↗
PubMed1977

Lung volumes in normal Cantonese subjects: preliminary studies.

Measurements of forced vital capacity (FVC), forced expiratory volume in one second (FEV1), FEV1/FVC ratio, functional residual capacity (FRC), total lung capacity (TLC), residual volume (RV), and RV/TLC ratio have been made in 331 normal Cantonese subjects (134 male and 197 female). The results have been expressed in multiple regression equations relating the volumes to age, height, and weight and have been compared with those of other workers. Lung volumes obtained in this study are in general lower for Chinese subjects than those reported for Caucasians. Similar findings for FVC were reported by Chuan and Chia (1969) in Singapore and by Wu and Yang (1962) in Taiwan. Significant differences, however, are noted for FRC, TLC, RV, and RV/TLC between our findings and those of Chuan and Chia. Our series is unbalanced because of an uneven distribution of age groups. In fact in none of the reported studies on Chinese subjects, including that of da Costa (1971), is the series large or balanced. Clearly, further research is required in this ethnic group to get more reliable predictive formulae for lung volumes.

Adolescent↗
PubMed1994

Tussometry and lung function.

The tussometric parameter peak value time (PVT) has been proposed as an objective measure of laryngeal function. Whether the lower respiratory tract function influences its value is, however, unknown. This study investigates the relationship between lung function parameters forced expiratory volume in 1 second, vital capacity, peak expiratory flow rate, forced expiratory flow at 50% of vital capacity and total lung capacity (FEV1, VC, PEFR, FEF50, TLC) and PVT in 79 subjects. PVT proved to be independent of lung function. It is therefore specifically a measure of laryngeal function, and lung function need not be considered when interpreting PVT values.

Adult↗
PubMed2005

Airway responses to the inhalation of cotton dust and cotton bract extracts.

BACKGROUND: Exposure to dust in the cotton industry is associated with respiratory dysfunction. Healthy subjects challenged with cotton bract extract (CBE) develop transient airway hyperresponsiveness. CBE, a major component of cotton dust, is potentially an important agent for studying byssinosis. OBJECTIVES: To compare airway responses to cotton dust extract (CDE) and CBE in healthy subjects. METHODS: In 21 healthy, non-smoking subjects we compared the effects of CBE and CDE in a double-blind random order, following a 10-min aerosol inhalation. The response to methacholine (MCh) 2 h following CBE or CDE was measured. Lung function was recorded using maximal (MEFV) and partial expiratory flow volume (PEFV) curves, measuring MEF at 60% of baseline vital capacity below total lung capacity [MEF40%(P)] on the PEFV curve. Responders were subjects who developed a 20% or greater fall in MEF40%(P) following extract challenge. Endotoxin levels were low for CBE (5.71 EU/mg) and CDE (31.88 EU/mg). RESULTS: There were 18 responders to CBE and 17 responders to CDE. The average maximal falls in MEF40%(P) were 70 +/- 4.9 and 70 +/- 4.4% of baseline (nonsignificant) following CBE and CDE, respectively. All subjects enhanced their MCh response following CBE or CDE. The MCh dose which reduced MEF40%(P) by 40% was identical for CBE and CDE (1.3 microg/ml). CONCLUSIONS: We conclude that CBE and CDE exert similar physiologic effects.

Adult↗
PubMedDate not supplied

Prevalence and features of advanced asbestosis (ILO profusion scores above 2/2). International Labour Office.

In this study, the author addressed the following question: Do workers with advanced asbestosis have a restrictive pulmonary physiology, and, alternately, do those who have restrictive physiological tests have advanced asbestosis? One group was identified by obvious radiographic measurements, and the other group was defined via physiologic measurements. Total lung capacity, vital capacity, and flows were measured in 12,856 men exposed to asbestos, of whom 3,445 had radiographic signs of asbestosis, as defined by the International Labour Office criteria. Radiographically advanced asbestosis-International Labour Office criteria profusion greater than 2/2 was present in 85 (2.5%) of men. An additional 52 men had physiologically restrictive disease. The author, who compared pulmonary flows and volumes of these two groups, used mean percentage predicted, adjusted for height, age, and duration of cigarette smoking. Men with radiographically advanced asbestosis had normal total lung capacity (i.e., 105.5% predicted), reduced forced vital capacities (i.e., 82.7% predicted), air trapping (i.e., residual volume/total lung capacity increased to 54.4%), and reduced flows (i.e., forced expiratory flow [FEF25-75] = 60.6% predicted, forced expiratory volume in 1 s = 78.0% predicted, and forced expiratory volume in 1 s/forced vital capacity = 65.5%). In contrast, men selected from the same exposed population for restrictive disease (i.e., reduced total lung capacity [72.6% predicted] and forced vital capacity [61.5% predicted]) also had airflow obstruction (i.e., forced expiratory volume in 1 s/forced vital capacity of 74.5% predicted) and air trapping (i.e., residual volume/total lung capacity of 46.7%). Only half of these men had asbestosis--and it was of minimal severity. In summary, advanced asbestosis was characterized by airway obstruction and air trapping, both of which reduced vital capacity but not total lung capacity; therefore, it was not a restrictive disease. In contrast, restrictive disease was rare and was associated with minimal asbestosis.

Aged↗
PubMed1996

Effect of renal transplantation on pulmonary function in patients with end-stage renal failure.

Ten patients with end-stage renal failure on maintenance dialysis underwent serial lung function tests before and at monthly intervals after renal transplantation. Mean values of forced expiratory volume within 1 s, forced vital capacity, and total lung capacity were within the normal range before and up to 6, months after transplantation. The mean value of residual volume (RV) was above the normal range during all periods measured (157.8 +/- 21.5% predicted before transplantation and 121.2 +/- 17.0% predicted at 6 months after transplantation). No statistically significant changes in lung volumes were detected over a course of 6 months, but there was a trend for a reduction in RV after transplantation. The single-breath diffusion capacity for carbon monoxide (DLCO) was in the high-normal range before transplantation (115.7 +/- 9.5% predicted). It remained high at 1 month after transplantation (124.5 +/- 12.2% predicted), but it gradually came down to the normal range from the 2nd month onwards. At 6 months after transplantation the mean DLCO was 83.8 +/- 7.3% of predicted which was significantly (p < 0.0001) lower than the value before transplantation. We conclude that raised DLCO and RV values occurred in patients with end-stage renal failure on maintenance dialysis which were most likely the result of pulmonary vascular congestion, and these abnormalities tend to improve after renal transplantation.

Adult↗