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At least 487 records · Page 27Linked to original sources
PubMed1976

Respiratory effects of live influenza virus vaccine: healthy older subjects and patients with chronic respiratory disease.

Twenty-one healthy, middle-aged volunteers and 8 patients with chronic lung disease were given live, attenuated influenza virus vaccine by nasal spray. Forced vital capacity, 1-sec forced expiratory volume, ratio of 1-sec forced expiratory volume to forced vital capacity, residual volume, ratio of airway conductance to lung volume, maximal expiratory flows after exhalation of 50 and of 75 per cent of the forced vital capacity, closing volume, slope of Phase III, volume of isoflow, single-breath diffusing capacity for CO, and arterial blood gases were measured before and 3, 7, 10, and 21 days after exposure. Vaccination was well tolerated by the healthy volunteers without change in pulmonary function. In contrast, the patients tended to develop increased respiratory symptoms and had a slight decrease in mean forced expiratory volume in 1 sec 3 weeks after vaccination.

Administration, Intranasal↗
PubMedDate not supplied

Respiratory function in recent pulmonary sarcoidosis with special reference to small airways.

This study was designed to evaluate airway dysfunction in relation to duration of disease in patients with pulmonary sarcoidosis for less than two years. Twenty four subjects with recent disease were compared with nine subjects with disease of more than two years' duration. They underwent lung function testing (lung volumes, lung transfer factor for CO and pulmonary mechanics). Small airway function was assessed using frequency dependence of compliance, closing volume, nitrogen single breath test and flow-volume curves breathing air and helium-oxygen mixture. Airway dysfunction was seen in pulmonary sarcoidosis even in some patients with recent disease and it became more evident in disease of longer duration. The results suggest small airway involvement. The frequency of airway dysfunction is difficult to evaluate, varying from estimates of 0% using flow-volume curves to 79% with frequency dependence of compliance. This apparent discrepancy could be explained by the consequences of parenchymal involvement leading to inhomogeneities in distribution of compliance, and of elastic lung recoil. We conclude that patients with recent sarcoidosis are probably affected by intrinsic small airway disease, but an increase in elastic recoil often conceals its consequences. The airway disease may not be apparent using conventional function tests and published predicted values.

Adult↗
PubMed1976

The effect of acute, intensive cigarette smoking on maximal expiratory flows and the single-breath nitrogen washout trace.

The effect of acute, intensive cigarette smoking on forced vital capacity and the single-breath expired N2 trace was studied in 82 smokers. There were significant decreases in the "effort-dependent" tests, such as peak flow and 1-sec forced expiratory volume, but no change in the more "effort-independent" tests, such as maximal mid-expiratory flow and maximal expiratory flow at 25 per cent of the vital capacity. Closing volume was unchanged in absolute terms and as a percentage of vital capacity. Closing capacity was unchanged in absolute terms and as a percentage of total lung capacity, but there was a significant increase in the slope of Phase III of the N2 washout curve after the acute smoking session. The tests of function that changed significantly after acute, intensive smoking were the ones that improved in 52 subjects who modified their smoking habits. The data suggest that acute, intensive cigarette smoking may be associated with an increase in resistance to air flow in the larger airways or a reduction in effort, and with increased nonuniformity of intraregional distribution of ventilation.

Adult↗
PubMedDate not supplied

Controlling bacterial contamination of an enteral formula through the use of a unique closed system: contamination, enteral formulas, closed system.

Contamination of enteral diets may play an essential role in formula tolerance and safety for patients. Contaminated enteral formula commonly support microbiological growth. Commercially sterile liquid formulas received from the manufacturer are required by the Food & Drug Administration (FDA) to be shelf-stable and free from enteric pathogens. This study examined the use of large volume, closed system containers in a typical nursing home. Large volume (1500 mL) containers with unique pierceable caps and piercing spikes were studied to determine their ability to reduce the incidence of microbiological contamination due to their design and ability to decrease handling requirements. This study took place in a room of a typical nursing home. In this clinical setting, 211 containers and administration spike sets were evaluated following a 36-h hangtime. Contamination was virtually nondetectable. Nursing staff in a clinical facility can effectively utilize a large volume, prefilled, ready-to-use feeding system to achieve delivery of noncontaminated product for up to 36 h hangtime.

Colony Count, Microbial↗
PubMed1998

Low level CO2 effects on pulmonary function in humans.

The purpose of the study was to determine whether chamber exposure to low levels of CO2 results in functional alterations in gas mixing and closing volume in humans. Four healthy volunteer subjects were exposed to 0.7% CO2 and to 1.2% CO2. Spirometry, lung volumes, single breath nitrogen washout, diffusing capacity for carbon monoxide (DLCO) by two methods, and cardiac output were measured in triplicate. Values were obtained over two non-consecutive days during the training period (control) and on days 2 or 3, 4, 6, 10, 13, and 23 of exposure to each CO2 level. Measurements were made during the same time of day. There was one day of testing after exposure, while still in the chamber but off carbon dioxide. The order of testing, up until measurements of DLCO and cardiac output, were randomized to avoid presentation effects. The consistent findings were a reduction in diffusing capacity for carbon monoxide and a fall in cardiac output, occurring to a similar degree with both exposures. For the group as a whole, there was no indication of major effects on spirometry, lung volumes, gas mixing or dead space. We conclude that small changes may occur in the function of distal gas exchanging units; however, these effects were not associated with any adverse health effects. The likelihood of pathophysiologic changes in lung function or structure with 0.7 or 1.2% CO2 exposure for this period of time, is therefore, low.

Breath Tests↗
PubMed1981

Reliability of echocardiographic and electrocardiographic parameters in assessing serial changes in left ventricular mass.

A reliable noninvasive index of left ventricular mass would be useful in following patients with valvular heart disease and left ventricular hypertrophy. We reviewed concurrent electrocardiograms and echocardiograms from 54 subjects, 39 patients with aortic or mitral valve disease and 15 normal subjects. Pre- and early postoperative echocardiographic estimates of left ventricular mass in 17 patients who had valve replacements correlated well (r = 0.96, p less than 0.001) and demonstrated little change in mean values despite altered left ventricular dimensions. Echocardiographic estimates of left ventricular mass were, therefore, used as a standard for evaluating other noninvasive indices. Precordial electrocardiographic voltage showed a weak correlation with left ventricular mass in the study group as a whole (r = 0.59, p less than 0.001), but no correlation in patients with volume overload (r = 0.36, p = NS). In 18 patients who had preoperative and three separate postoperative studies at least eight weeks apart, changes in left ventricular cross-sectional area (an index of left ventricular mass which corrects for changes in left ventricular volume) closely followed alterations in left ventricular mass. However, changes in posterior wall and interventricular septal thickness often resulted from altered ventricular volume and did not accurately reflect directional changes in left ventricular mass. Serial changes in electrocardiographic voltage were similarly unreliable. We conclude that left ventricular mass and cross-sectional area by echocardiography allow accurate noninvasive assessment of left ventricular mass, whereas wall thickness and electrocardiographic changes do not.

Cardiomegaly↗
PubMed1983

[Studying pulmonary mechanics in intensive care].

Assessing pulmonary function in critically ill patients is difficult, mainly because of lack of cooperation, artificial ventilation and jeopardized vital functions. We describe bedside methods and mobile equipment used to measure lung volumes, static pulmonary and thoracic compliance. The analysis of single and multiple-breath nitrogen washout curves allows an estimation of closing volume and an assessment of the inhomogeneity of ventilation. The use of a microcomputer facilitates recording, calculation, reproduction and classification of the data; it also permits the collection of more information in a shorter time, allowing the adjustment of mechanical ventilation to the underlying pulmonary disease.

Critical Care↗
PubMed1993

Relation between distal airspace size, bronchiolar attachments, and lung function.

BACKGROUND--Smoking related fixed airway obstruction may be due to airway scarring and narrowing or decreased support due to loss of adjacent alveolar walls. In this study of resected specimens, preoperative pulmonary function was compared with results of a morphometric study of lung structure. METHODS--Morphometric measurements were made on 42 inflation fixed lung specimens as follows: airspace wall surface area per unit volume (AWUV) was measured on at least 25 l mm2 histological fields from each specimen, expressed as a mean, and the mean of the lowest five measurements for each case (LF5). Minimum diameter, maximum diameter, diameter ratio (ellipticality), lumen area, and lumen circumference were measured on at least 16 non-respiratory bronchioles from each lung. Peribronchiolar alveolar support was measured as mean interalveolar attachment distance (IAAD). Measurements of pulmonary function included forced expiratory volume in one second (FEV1) (absolute and % predicted values; n = 42), slope of phase III (single breath nitrogen test; n = 28), closing volume (expressed as a percentage of vital capacity (CV/VC%); n = 28). RESULTS--Bronchiolar size was not independently related to the tests of lung function used. Percentage predicted FEV1 was related to mean IAAD, ellipticality, and mean AWUV. CV/VC% showed significant relation with ellipticality, mean AWUV, and LF5 AWUV. Slope of phase III increased with increasing IAAD. Significant correlations were found between ellipticality and AWUV (mean and LF5), and between ellipticality and IAAD. Both IAAD and ellipticality were significantly increased in patients with abnormally low FEV1. CONCLUSION--Destruction of airspace walls, particularly those attached to the peripheral bronchioles, is more influential in determining airflow limitation than bronchiolar size.

Aged↗
PubMed1983

The effects of intravenous infusion of saline on lung density, lung volumes, nitrogen washout, computed tomographic scans, and chest radiographs in humans.

In this study we examined the effect of a 15% increase in extracellular fluid volume on lung density, lung volumes, nitrogen washout, chest radiographs and computerized tomographic (CT) scans of the thorax in 5 volunteers. The objective of the study was to determine the sensitivity of these techniques in detecting small changes in lung water. Lung density was measured by a gamma ray Compton scatter technique and with an Ohio nuclear delta 2020 CT scanner. We measured or derived functional residual capacity, residual volume (RV), vital capacity (VC), and total lung capacity by helium dilution. Single-breath nitrogen washout was used to measure closing volume and the slope of phase III nitrogen washout (delta N2). Chest radiographs were taken in the posteroanterior and lateral projections. With the CT scanner we obtained slices 1 cm thick through the bases of the lungs and at 6 and 12 cm up from the bases. All these measurements were made before and 20 to 90 min after the intravenous infusion of 30 ml/kg body weight of warm saline over a period of 20 min. The most striking findings were a 24% increase in delta N2, a 14% increase in RV, and a 4.5% decrease in VC. Chest radiographs and the CT scans showed an increase in the size of the azygos veins. There was no change in Compton scatter density or the CT numbers. These results suggest that (1) tests of small airway function, such as RV and delta N2, are more sensitive than radiographic techniques to small increases in lung water, (2) there is some protection of the lung to increases in extracellular fluid volume.

Adult↗
PubMed1979

Erythrokinetic studies in hairy-cell leukaemia.

Erythrokinetics were studied in 29 patients with hairy-cell leukaemia. In all cases there was an increase in plasma volume, closely correlated to the size of the spleen, indicating that the true degree of anaemia can only be appreciated by red cell volume measurement. Moderately increased haemolysis was observed in most cases, which did not correlate with the spleen size. Simultaneous study of autologous and isologous red cell life-span suggested an extra-corpuscular mechanism for the haemolysis in most patients. A quantitative erythropoietic defect, either relative or absolute, was found in half the cases, without any qualitative defect. Only one case showed erythroid metaplasia of the spleen. Thus marrow failure appears to be largely responsible for the anaemia and granulocytopenia in hairy-cell leukaemia. A clear correlation was shown between the short-term prognosis after splenectomy and the degree of hypersplenism. However, long-term survival correlated chiefly with the degree of bone marrow failure, whether splenectomy had been carried out or not. The results indicate that isotope studies in hairy-cell leukaemia are useful both in determining the best form of treatment and predicting survival.

Adult↗
PubMed1998

Identification of smokers susceptible to development of chronic airflow limitation: a 13-year follow-up.

BACKGROUND: Cigarette smoking is the cardinal cause of COPD, but only a relatively small percentage of smokers have development of clinically overt disease. OBJECTIVES: To identify high-risk subjects and to assess the prognostic significance of "small airways" tests. SETTING: University teaching hospital. SUBJECTS: Fifty-six smokers and ex-smokers of mean age 62.5 years (SD, 2.7) with a smoking history of 40.6 (18.9) pack-years were studied at the end of a 13-year follow-up period. MEASUREMENTS: Questionnaire and lung function tests, including static and dynamic lung volumes, airway resistance, maximal expiratory flow rates, and small airways tests, such as nitrogen slope of the alveolar plateau (N2 slope) and closing volume. RESULTS: Eighty-two percent of subjects with a normal FEV1/vital capacity (VC) ratio at the start of the study (half of them with abnormal results of small airways tests) still had a normal FEV1/VC ratio 13 years later. In the remainder, all but one had final FEV1/VC values >60%. About 80% of subjects with a decreased FEV1/VC at the start (subjects with airflow obstruction) reached at the end of study lower than predicted FEV1/VC values. Only about 10% of these subjects showed an accelerated loss of FEV1, reaching end FEV1/VC values of <45%. Initial N2 slope predicted about 80% of end FEV1 values. CONCLUSION: Middle-aged smokers are at no evident risk of functional deterioration if their FEV1/VC ratio is normal. This is so even if results of small airways tests are abnormal. A decreased FEV1/VC ratio has no serious implications in itself. Only an associated high N2 slope adds the necessary information to predict a low FEV1. Present data suggest that a subgroup of smokers in their 50s, characterized by a low FEV1/VC ratio and a high N2 slope, are probably the susceptible smokers at high risk for development of COPD.

Airway Obstruction↗
PubMed1982

Terbutaline aerosol from a metered dose inhaler via a 750 ml spacer. Effect on large and small airways.

The effect on large and small airways of a pressurized terbutaline aerosol delivered via a 750 ml spacer, or via an ordinary actuator, was investigated in a double-blind study of 15 patients with reversible obstructive airflow disease. There was significant bronchodilatation with both devices as measured by Raw, FEV1.0, PEFR, MEF75, MEF50, and MEF25. Raw showed, a significant difference in favour of the 750 ml spacer. Measurement of Closing Volume (CV) revealed a significant decrease with the spacer, but with the ordinary actuator there was a slight increase in CV; the difference between the devices was significant. The quotient Closing Volume/Vital Capacity (CV/VC%) was significantly decreased with the 750 ml spacer but not with the ordinary actuator. The decrease in volume of isoflow (VisoV) was more pronounced with the spacer but not significantly so. The results suggest that use of a 750 ml spacer may promote more extensive peripheral deposition of the drug in the bronchial tract.

Aerosols↗
PubMed1977

Airway function in sarcoidosis.

Airway function was studied in 18 patients with sarcoidosis, aged 18 to 49 years. Eleven of the patients were smokers. All patients had the characteristic functional changes of restrictive lung disease: decreased lung volumes and single breath diffusing capacity, and increased static transpulmonary pressures. Abnormal airway function was demonstrated in every patient by at least one test, and nearly always by multiple tests. Specific airway conductance was abnormally low in two patients. The ratio of the 1 second forced expiratory volume to the forced vital capacity was decreased in six patients. Frequency dependence of dynamic compliance was demonstrated in eight patients. The ratio of closing volume to vital capacity was increased above age-corrected predictions in all but two patients. Upstream airway resistance was abnormally increased in 16 of the patients. These results suggest that airway dysfunction is not uncommon in sarcoidosis.

Adolescent↗
PubMed1999

Small airways obstruction syndrome.

STUDY OBJECTIVES: To clarify the significance of a functional lung pattern characterized by a decreased vital capacity (VC) and an increased residual volume (RV), but with a normal FEV1/VC ratio. SETTING: A university teaching hospital. SUBJECTS: Patients with bronchial asthma, pulmonary emphysema, and small airways disease, and older subjects. MEASUREMENTS: Measurements of static and dynamic lung volumes, diffusing capacity of the lung for carbon monoxide (as measured by the single-breath method), nitrogen slope of the alveolar plateau, and closing volume (as measured by the single-breath O2 test). CONCLUSION: A functional pattern characterized by a decreased VC and FEV1 and increased RV, but with a normal FEV1/VC ratio and total lung capacity, reflects an obstructive impairment of small airways.

Adult↗
PubMedDate not supplied

Measurement of tympanic membrane displacement arising from aural cardiovascular activity, swallowing, and intra-aural muscle reflex.

A new technique based on constant pressure metrology has been developed to measure displacement of the tympanic membrane. Known as the Tympanic Membrane Displacement Measurement System (TMD system), this device is designed to be suitable for application in the audiology clinic. The TMD system resolves volume displacements as small as a nanolitre. Measurements are absolute--being independent of volume and compliance of the external auditory meatus, have a wide dynamic range, and are essentially made under free-field conditions. It employs closed volume metrology which allows the meatal pressure to be varied independently of the ambient pressure. The principle of constant pressure metrology using a standard TDH-39 headphone cone is discussed. Details are provided on the electronics, mechanical hardware, and software used for evaluating aural cardiovascular activity, stapedial muscle reflex, swallowing and Eustachian tube function.

Acoustic Impedance Tests↗
PubMed1976

Influence of diaphragmatic contraction on ventilation distribution in horizontal man.

The washout of a bolus of helium (inhaled from residual volume) during relaxed expiration (RE) through a resistance was compared with that during expiration with voluntary diaphragmatic contraction (VDCE) achieved by tensing the abdominal muscles while maintaining constant expiratory flow (less than 0.4 l/s). In six subjects in the lateral decubitus position, phase IV during RE started at 58 +/- 1.6% vital capacity (VC) (mean +/- 1 SE). During VDCE, when the transdiaphragmatic pressure (Pdi) exceeded 30 cmH2O, phase IV commenced at 8.2 +/- 0.8% VC. The expired He concentration (FEHe) at lung volumes greater than 70% VC was 1.3 +/- 0.05 times that during RE. In supine subjects VDCE flattened the slope of the alveolar plateau and decreased closing volume by 3.7 +/- 0.4% VC. Our results suggest that when the diaphragm is relaxed in the horizontal subject, the hydrostatic gradient of pressure within the abdomen enhances early emptying of dependent lung zones. Diaphragmatic contraction results in more homogeneous emptying. We conclude that diaphragmatic tone influences the vertical gradient of regional volume, and hence of pleural pressure. The latter is not constant, being less during inspiration than during expiration. Therefore, differences in the changes of applied pressure between dependent and nondependent lung regions influence ventilation distribution in subjects in the horizontal posture.

Diaphragm↗
PubMed1985

Bronchial reactivity to histamine in young male smokers.

Bronchial reactivity to inhaled histamine was determined in 17 non-asthmatic young male smokers and 21 non-smokers who were free of airflow obstruction. The 2 groups were similar in forced expiratory volume, maximal expiratory flow at 50% and 25% of vital capacity, slope of phase III of the single-breath nitrogen test (delta N2/l) and closing volume (CV/VC%). Bronchial reactivity was determined as PC20, provocation concentration reducing FEV1 by 20%, threshold concentration reducing FEV1 by two standard deviations, percentage reduction in FEV1 with histamine 16 mg/ml. Similar numbers of smokers and non-smokers had a PC20 below 16, 32 and 64 mg/ml. Threshold concentrations were the same in smokers and non-smokers, as was the reduction in FEV1 with histamine 16 mg/ml. The bronchoconstrictor response to histamine was significantly related to baseline measurements of expiratory flow (particularly in non-smokers), but not to delta N2/l or CV/VC%. Bronchial reactivity to histamine is not increased in young male smokers with normal lung function. The abnormal reactivity seen in older smokers is acquired, either from prolonged exposure to cigarette smoke itself, or resultant airway narrowing.

Adult↗
PubMedDate not supplied

Hydrodynamic test of bioprostheses in the mitral position.

With the described circulation simulator it is possible to simulate physiological values of pulse frequency, filling volume and pressure. Bioprostheses with pathological changes can be investigated in vitro under normal and under specific pathological in vivo circulation conditions. The criteria of classification of the effectiveness of bioprostheses are reflux volume, VR, insufficiency, I and maximal orifice area, A. As a result of the definition of insufficiency, even intact bioprostheses show insufficiency with regard to the closing volume. While the effectiveness of perforated bioprostheses can be clearly demonstrated by reflux volume and insufficiency, the regurgitation of a stenosed valve gives no meaningful statement as to its effectiveness. In this case, the orifice area, A, is a suitable criterion of the classification of effectiveness.

Bioprosthesis↗