Diffusing capacity of the lung in pulmonary emphysema

1964 ◽  
Vol 19 (5) ◽  
pp. 981-989 ◽  
Author(s):  
Stephen M. Ayres ◽  
Meta E. Buehler ◽  
Ruth G. Armstrong
Keyword(s):  
Gas Chromatography ◽  
Carbon Monoxide ◽  
Steady State ◽  
Body Size ◽  
Normal Subjects ◽  
Mean Value ◽  
Diffusing Capacity ◽  
Common Cause ◽  
Abnormal Distribution ◽  
The Mean

Steady-state CO and O2 methods for measuring pulmonary diffusing capacity may be affected by abnormal distribution of inspired gas relative to perfusion. These methods frequently fail to separate abnormalities in diffusion from abnormalities in distribution in patients with obstructive emphysema. A rebreathing CO method has been developed which, in theory, is less sensitive to inequalities in distribution. The DlCO by this method in 41 normal subjects averaged 20.8 ± 8.6 ml/min mm Hg and was closely correlated with body size and lung volume. Only 3 of 25 patients with obstructive emphysema had a DlCO less than the 95% confidence level although the mean value for all of the patients (16.8 ml/min mm Hg) was significantly lower than that of the normal group. It is concluded that loss of diffusing surface is not a common cause of oxyhemoglobin desaturation in obstructive emphysema. diffusion; carbon monoxide; ventilation-to-perfusion; gas chromatography Submitted on December 27, 1963

Rate of uptake of carbon monoxide at different inspired concentrations in humans

1982 ◽  
Vol 52 (1) ◽  
pp. 109-113 ◽  
Author(s):  
H. A. Jones ◽  
J. C. Clark ◽  
E. E. Davies ◽  
R. E. Forster ◽  
J. M. Hughes
Keyword(s):  
Carbon Monoxide ◽  
Transport System ◽  
Human Lung ◽  
Normal Subjects ◽  
Facilitated Transport ◽  
Diffusing Capacity ◽  
Normal Human ◽  
The Mean ◽  
Co Concentrations

The rate of uptake of carbon monoxide (CO) in the lungs of normal subjects were measured at inspired concentrations of less than 1, 300, and 3,000 ppm (less than 0.0001–0.3%) using radioactive CO (11CO). In nine subjects the rate of uptake was monitored at the mouth during rebreathing. At inspired CO concentrations of approximately 1, 300, and 3,000 ppm and a mean alveolar O2 fraction of 0.15, the mean lung diffusing capacity was 25.8, 26.4, and 25.3 ml . min-1. Torr-1, respectively. In seven subjects the measurements were repeated after a period of O2 breathing, giving a mean alveolar O2 fraction of 0.78. The calculated membrane diffusing capacity was 31.9, 33.7, and 32.0 ml . min-1. Torr-1 at less than 1, 300, and 3,000 ppm inspired CO. We conclude that there is no difference in the rate of uptake of CO over the range of concentrations studied in these experiments. No evidence for the presence of a facilitated transport system for CO in the normal human lung was found.

DlCO measurements with gas chromatography

1962 ◽  
Vol 17 (6) ◽  
pp. 856-860 ◽  
Author(s):  
Josef R. Smith ◽  
Lyle H. Hamilton
Keyword(s):  
Gas Chromatography ◽  
Normal Subjects ◽  
Inert Gas ◽  
Breath Holding ◽  
Gas Mixture ◽  
Diffusing Capacity ◽  
Gas Chromatograph ◽  
Excellent Correlation ◽  
Pulmonary Diffusing Capacity ◽  
The Mean

A gas chromatograph has been used to analyze gases for the measurement of pulmonary diffusing capacity using the breath-holding technique. The gas mixture used for the measurement consisted of carbon monoxide in air with neon as the insoluble inert gas. The calculated DlCO was unaffected when sulphur hexafloride (SF6) or He was substituted for Ne in the mixture, but since CO and Ne could be most simply and rapidly analyzed, this combination was preferred for the gas mixture used to measure DlCO. The mean DlCO for ten normal subjects was 25.8 ± 4.2 ml/min mm Hg. These results were comparable to values reported in the literature when established methods of analysis were used. An excellent correlation was found between calculated DlCO and the clinical condition of patients with impaired pulmonary diffusing capacity. Submitted on February 14, 1962

The effect of conductive ventilation heterogeneity on diffusing capacity measurement

2008 ◽  
Vol 104 (4) ◽  
pp. 1094-1100 ◽  
Author(s):  
Sylvia Verbanck ◽  
Daniel Schuermans ◽  
Sophie Van Malderen ◽  
Walter Vincken ◽  
Bruce Thompson
Keyword(s):  
Carbon Monoxide ◽  
Vital Capacity ◽  
Experimental Situation ◽  
Normal Subjects ◽  
Diffusing Capacity ◽  
Capacity Measurement ◽  
Alveolar Volume ◽  
Estimation Errors ◽  
Single Breath ◽  
Ventilation Heterogeneity

It has long been assumed that the ventilation heterogeneity associated with lung disease could, in itself, affect the measurement of carbon monoxide transfer factor. The aim of this study was to investigate the potential estimation errors of carbon monoxide diffusing capacity (DlCO) measurement that are specifically due to conductive ventilation heterogeneity, i.e., due to a combination of ventilation heterogeneity and flow asynchrony between lung units larger than acini. We induced conductive airway ventilation heterogeneity in 35 never-smoker normal subjects by histamine provocation and related the resulting changes in conductive ventilation heterogeneity (derived from the multiple-breath washout test) to corresponding changes in diffusing capacity, alveolar volume, and inspired vital capacity (derived from the single-breath DlCO method). Average conductive ventilation heterogeneity doubled ( P < 0.001), whereas DlCO decreased by 6% ( P < 0.001), with no correlation between individual data ( P > 0.1). Average inspired vital capacity and alveolar volume both decreased significantly by, respectively, 6 and 3%, and the individual changes in alveolar volume and in conductive ventilation heterogeneity were correlated ( r = −0.46; P = 0.006). These findings can be brought in agreement with recent modeling work, where specific ventilation heterogeneity resulting from different distributions of either inspired volume or end-expiratory lung volume have been shown to affect DlCO estimation errors in opposite ways. Even in the presence of flow asynchrony, these errors appear to largely cancel out in our experimental situation of histamine-induced conductive ventilation heterogeneity. Finally, we also predicted which alternative combination of specific ventilation heterogeneity and flow asynchrony could affect DlCO estimate in a more substantial fashion in diseased lungs, irrespective of any diffusion-dependent effects.

Comparison of Emission Levels of Motor Cars, Motorcycles, and Tricycles Using Petrol Engines in Southwestern Nigeria

2021 ◽  
Vol 900 ◽  
pp. 183-187
Author(s):  
Odunlami Olayemi Abosede ◽  
Akeredolu Funso Alaba
Keyword(s):  
Carbon Dioxide ◽  
Carbon Monoxide ◽  
Carbon Dioxide Emissions ◽  
Mean Value ◽  
Southwestern Nigeria ◽  
Mean Values ◽  
Mobile Sources ◽  
Southwest Nigeria ◽  
The Mean ◽  
European Standards

The emissions of carbon monoxide, carbon dioxide, and hydrocarbon from four stroke-powered motorcars and two stroke-powered motorcycles and tricycles in Southwest Nigeria were examined using an automotive 4-gas analyer. Results show that tricycles produced more hydrocarbon and carbon monoxide emissions than motorcycles, while motorcycles emitted more of these pollutants than the gasoline fueled motor cars. (The gasoline fueled motorcars produced lowest hydrocarbon and carbon monoxide while the tricycles produced the highest hydrocarbon and carbon monoxide emissions). On the contrary, motor cars had the highest mean value of carbon dioxide followed by the motorcycles, while tricycles had the least. This could be attributed to the presence of the catalytic converters in some of the motor cars oxidizing carbon monoxide to carbon dioxide. The mean values of hydrocarbon, carbon monoxide and carbon dioxide emissions from motorcars are 630ppm, 10200ppm and 59900ppm. This is much higher than the NESREA (National Environmental standards and Regulations Enforcement Agency) standards as well as Euro II and Euro III (European standards) for vehicular emission. The mean values for hydrocarbon, carbon monoxide and carbon dioxide emissions from motorcycles and tricycles are (2150ppm, 21530ppm and 31200ppm) and (2820ppm, 24880ppm and 38710ppm) respectively. These results do not comply with Nigeria and European emission standards for hydrocarbon, and carbon monoxide. Tricycles and motorcycles account for higher concentrations of hydrocarbon and carbon monoxide pollutants from mobile sources, while they emit carbon dioxide minimally.

III. PULMONARY DIFFUSION

PEDIATRICS ◽  
1965 ◽  
Vol 35 (1) ◽  
pp. 185-193
Author(s):  
George R. DeMuth ◽  
William F. Howatt
Keyword(s):  
Carbon Monoxide ◽  
Body Size ◽  
Longitudinal Data ◽  
Surface Area ◽  
Residual Variance ◽  
Normal Variation ◽  
Diffusing Capacity ◽  
Healthy Individuals ◽  
Lung Volumes ◽  
Mean Values

1. Equations describing the normal variation and changes with size of the diffusing capacity (rebreathing technique) for boys and girls have been obtained from 230 observations on 139 children. 2. The use of covariance analysis on the longitudinal data reduces the residual variance by about half, indicating that in children the diffusing capacity for carbon monoxide, Dco, grows along growth lines. This aids in finding significant deviations from the predicted in children who are followed with repeated examinations. 3. The Dco increases with growth in a manner very similar to that of the lung volumes, not only in respect to height, but also in respect to age, weight, and surface area. The ratio Dco/TLC expresses a relationship which does not vary with body size, age, or sex in these healthy individuals. Although boys and girls have the same mean values, the correlation between each individual's values from the two series is significant for boys but not for girls. 4. The constancy of the Dco/TLC during growth supports the hypothesis that the lung grows between the ages of 5 and 18 years by the addition of new air spaces rather than by enlarging the pre-existing ones.

Effect of 1,25-(OH)2D3 on jejunal absorption of magnesium in patients with chronic renal disease

1980 ◽  
Vol 238 (4) ◽  
pp. G349-G352 ◽  
Author(s):  
A. C. Schmulen ◽  
M. Lerman ◽  
C. Y. Pak ◽  
J. Zerwekh ◽  
S. Morawski ◽  
...  
Keyword(s):  
Vitamin D ◽  
Renal Disease ◽  
Chronic Renal Disease ◽  
Normal Subjects ◽  
Mean Value ◽  
Normal Serum ◽  
Perfusion Technique ◽  
Dihydroxyvitamin D3 ◽  
Jejunal Absorption ◽  
The Mean

These studies were performed to see if jejunal malabsorption of magnesium in patients with chronic renal disease was influenced by therapy with 1 alpha, 25-dihydroxyvitamin D3 [1,25-(OH)2D3; 2 microgram/day by mouth for 7 days]. This treatment restored normal serum concentrations of the vitamin D metabolite from 0.9 +/- 0.2 to 4.2 +/- 0.6 ng/dl. Jejunal absorption of magnesium, measured by a triple-lumen constant-perfusion technique, was enhanced in each of the seven patients by this therapy. The mean value rose from 0.04 +/- 0.02 to 0.13 +/- 0.02 mmol . 30 cm-1 . h-1. This last value is similar to the magnesium absorption rate in untreated normal subjects. These results demonstrate that magnesium absorption in the human jejunum is dependent on vitamin D, and they show that 1 alpha,25-dihydroxyvitamin D3 therapy in patients with chronic renal failure is associated with an enhanced jejunal absorption of magnesium.

Sickle cell crisis as evaluated from measurements of hydroxybutyrate dehydrogenase and myoglobin in plasma.

1981 ◽  
Vol 27 (2) ◽  
pp. 314-316 ◽  
Author(s):  
E F Roth ◽  
P A Bardfeld ◽  
S J Goldsmith ◽  
E Radel ◽  
J C Williams
Keyword(s):  
Steady State ◽  
Sickle Cell Disease ◽  
Sickle Cell ◽  
High Specificity ◽  
Mean Value ◽  
Cell Disease ◽  
Sickle Cell Crisis ◽  
The Mean ◽  
Low Sensitivity ◽  
Sickle Cell Crises

Abstract Data on plasma hydroxybutyrate dehydrogenase activity (I) and myoglobin concentration were used to evaluate painful sickle cell crises. I was increased during non-crisis steady state in patients with sickle cell disease as compared to normal values (232, SD 79.7 vs 85, SD 33 Sigma units/mL). During crisis, the mean value for I increased further to 379 (SD 139) Sigma units/mL. For 12 patients evaluated both during steady state and crisis, there was a mean increase in plasma I of 131% (SD 76%). Repeated determinations of I in sickle cell disease patients during several months while they were in steady state showed that baseline I varied by no more than 20% from the mean. Plasma myoglobin in patients with sickle cell disease was not above normal, but during crisis 21 of 39 patients tested had increased plasma myoglobin concentrations. Our data suggest that I may be a useful indicator of sickle cell crisis when the patient's own baseline value is available for comparison. Plasma myoglobin measurements give evidence of muscle damage during crisis with high specificity but low sensitivity.

Effects of altering ventilation on steady-state diffusing capacity for carbon monoxide

1963 ◽  
Vol 18 (1) ◽  
pp. 89-96 ◽  
Author(s):  
Kaye H. Kilburn ◽  
Harry A. Miller ◽  
John E. Burton ◽  
Ronald Rhodes
Keyword(s):  
Carbon Monoxide ◽  
Steady State ◽  
Tidal Volume ◽  
Lung Volume ◽  
Dead Space ◽  
Control Level ◽  
Alveolar Ventilation ◽  
Positive Pressure ◽  
Diffusing Capacity ◽  
Fixed Rate

Alterations in the steady-state diffusing capacity for carbon monoxide (Dco) by the method of Filley, MacIntosh, and Wright, produced by sequential changes in the pattern of breathing were studied in anesthetized, paralyzed, artificially ventilated dogs. The Dco of paralyzed, artificially ventilated control dogs did not differ significantly during 3 hr from values found in conscious and anesthetized controls. A fivefold increase in tidal volume without changing frequency of breathing raised alveolar ventilation and CO uptake 500% and Dco 186%. A high correlation between tidal volume and Dco was noted during reciprocal alterations of tidal volume and rate which maintained minute volume. The Dco appeared to fall when alveolar ventilation was tripled by increments of rate with a fixed-tidal volume, despite a 63% increase in CO uptake. Doubling end-expiratory lung volume by positive pressure breathing without altering tidal volume or rate did not affect Dco. The addition of 100 ml of external dead space with rate and tidal volume constant decreased Dco to 42% of control level, however, stepwise reduction of dead space from 100 ml to 0 in two dogs failed to change Dco. Added dead space equal to frac12 tidal volume (170 ml) reduced Dco to 25% of control in two dogs with a return to control with removal of dead space. Thus, in paralyzed artificially ventilated dogs, tidal volume appears to be the principal ventilatory determinant of steady-state Dco. Dco is minimally affected by increases in alveolar ventilation with a constant tidal volume effected by increasing the frequency of breathing. Prolonged ventilation, at fixed rate and volume, and increased dead space either did not effect, or they reduced Dco, perhaps by rendering less uniform the distribution of gas, and blood in the lungs. Although lung volume was doubled by positive-pressure breathing, pulmonary capillary blood volume was probably reduced to produce opposing effects on diffusing capacity and no net change. Submitted on March 14, 1962

The Dynamics of Cumulative Step Size Adaptation on the Ellipsoid Model

2016 ◽  
Vol 24 (1) ◽  
pp. 25-57 ◽  
Author(s):  
Hans-Georg Beyer ◽  
Michael Hellwig
Keyword(s):  
Steady State ◽  
Linear Convergence ◽  
Search Space ◽  
Mean Value ◽  
Superior Performance ◽  
Noisy Environments ◽  
Step Size ◽  
State Behavior ◽  
Closed Form Solutions ◽  
The Mean

The behavior of the [Formula: see text]-Evolution Strategy (ES) with cumulative step size adaptation (CSA) on the ellipsoid model is investigated using dynamic systems analysis. At first a nonlinear system of difference equations is derived that describes the mean value evolution of the ES. This system is successively simplified to finally allow for deriving closed-form solutions of the steady state behavior in the asymptotic limit case of large search space dimensions. It is shown that the system exhibits linear convergence order. The steady state mutation strength is calculated, and it is shown that compared to standard settings in [Formula: see text] self-adaptive ESs, the CSA control rule allows for an approximately [Formula: see text]-fold larger mutation strength. This explains the superior performance of the CSA in non-noisy environments. The results are used to derive a formula for the expected running time. Conclusions regarding the choice of the cumulation parameter c and the damping constant D are drawn.

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