The Measurement of the Pulmonary Diffusing Capacity in the Presence of Lung Disease

Bates, David V.

doi:10.1172/jci103642

Cited by 39 publications

(22 citation statements)

References 26 publications

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“…The steady state method using end-tidal samples therefore gives falsely low figures for the over-all diffusing capacity of the lung. Bates (22) believes the steady state method with end-tidal sampling reflects the diffusing capacity of the predominantly ventilated portion of the lung.…”

Section: Resultsmentioning

confidence: 99%

Pulmonary Diffusing Capacity: A Comparison of Breath-Holding and Steady State Methods Using Carbon Monoxide

Apthorp¹,

Marshall²

1961

J. Clin. Invest.

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Three methods are in current use for measuring the diffusing capacity of the lungs for carbon monoxide (DL). Two of these are steady state methods, and they differ in the methods used to calculate the mean alveolar carbon monoxide tension. Filley, MacIntosh and Wright (1) calculate the alveolar Pco indirectly, assuming the physiological dead space for carbon dioxide to be the same as that for carbon monoxide, while Bates, Boucot and Dormer (2) use the end-tidal Pco as the mean alveolar Pco. The third method is the single breath method of Krogh and Krogh (3) as modified by Ogilvie, Forster, Blakemore and Morton (4). Each method in theory measures the total resistance to gas diffusion offered by the structures that lie between the gas in the alveoli and the hemoglobin within the red cells of the pulmonary capillaries. The results obtained by each method differ in normal subjects; and in disease states, such as emphysema, the differences may be great. While the different results obtained in similar subjects by the two steady state methods can largely be explained by the different methods of estimating the mean alveolar Pco (5), the breath-holding method consistently gives higher results than either of the steady state methods (6). Marshall (7) has recently compared the breath-holding method of measuring DL with a steady state method, using end-tidal samples in a small group of normal subjects and patients with emphysema. He found that, while in normal subjects the end-tidal sample satisfactorily reflected the mean alveolar Pco, in emphysema with impaired intrapulmonary gas mixing, the end-tidal sample overestimates the mean alveolar Pco and therefore gives falsely low results for the diffusing capacity. These results The present study was made 1) to compare the single breath and steady state methods in a large group of subjects with widely varying intrapulmonary gas mixing; and 2) since abnormalities of intrapulmonary gas mixing cannot explain the differences that occur between the two methods in normal subjects, a study was made of the variations in the type of breathing which might influence the results of the steady state method in normal subjects. METHODSThe steady state method used was that of Bates and co-workers (2) but the apparatus was modified in a number of details. The valve assembly consisted of single inspiratory and expiratory valves set in 2.5 cm-bore metal tubing in order to reduce the dead space and allow end-tidal samples to be obtained with smaller tidal volumes than were possible with the original apparatus. An automatic end-tidal sampler, triggered by a change in pressure at the mouthpiece, snatched a 35 ml sample at the end of each breath. During the test the subject breathed 0.125 per cent carbon monoxide in air; 1.5 minutes was allowed for the subject to reach a steady state and the expired gas was collected for a further 2 minutes during which time end-tidal samples were taken. The CO concentration in the inspired, mixed expired and end-tidal samples was measured by an infrared analyzer....

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Section: Resultsmentioning

confidence: 99%

Pulmonary Diffusing Capacity: A Comparison of Breath-Holding and Steady State Methods Using Carbon Monoxide

Apthorp¹,

Marshall²

1961

J. Clin. Invest.

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“…The global diffusing capacity was determined with Bates' method [ 13]. VE and VO2 were determined with a Tissot spirometer and using Scholandcr technique.…”

Section: Methodsmentioning

confidence: 99%

“…The total capacity (TLC) and the timed vital capacity of each lung (FEVT) have been studied also with differential spiro metry [10][11], K anagami et at. [12] studied the diffusion capacity of each lung using Bates method of rebreathing with determination of end tidal car bon monoxide (CO) (D LC 08s2) in lieu of arterial CO tension [13]. Ogilvie et al [14], T urino et al [15] and G lauser [16] used single breath diffusing tech nique for this purpose.…”

Section: Introductionmentioning

confidence: 99%

Factors Influencing the Diffusing Capacity of Each Lung

Lopéz-Majano¹,

Dutton²

1972

Respiration

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18 patients with pulmonary tuberculosis and ventilatory insufficiency had a differential spirometry with determination of the following parameters in each lung: oxygen uptake, ventilation, vital capacity and diffusing capacity. Lung scintigraphy was also performed. The factors influencing the diffusing capacity of each lung were the ventilation and the pulmonary arterial blood flow because there was a high correlation between each of these parameters and diffusing capacity – 0.9702 and 0.9634, respectively.

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“…Marshall [1958] and Bates [1958] found that the end-tidal estimate of PACO is larger than for Filley's method, therefore giving lower DLCO. Forster, Fowler and Bates [1954] and Bates [1958] postulated that the end-tidal method measures only the ventilated part of the lung, while the Filley method may measure in addition, lung that was perfused but not ventilated. Discrepancies in estimates of pulmonary diffusing capacity caused by uneven distribution of ventilation, diffusion and perfusion have been studied by Chinet, Michele and Haab [1971], and others using a continuous flow model.…”

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confidence: 95%

Temporal Effects in the Estimation of Pulmonary Diffusing Capacity

Kindig

Hazlett

1977

Exp Physiol

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Steady state estimates of the pulmonary diffusing capacity for carbon monoxide (DLco) require measurement of the uptake and the average alveolar partial pressure of carbon monoxide (PACO). The expired alveolar sample obtained by different experimental methods and/or breathing patterns rarely represents the actual PACO. It is widely accepted that nonuniform distribution of ventilation, diffusion and perfusion causes discrepancies in the measurement of diffusing capacity. An additional source of error in choosing PACO arises in the sampling time chosen by the experimental method. A theoretical study of a ramp-with-pause and a square breathing pattern demonstrates that the sample-time error exists even in the homogeneous lung. The study shows for the homogeneous lung that the correct fractional concentration of alveolar carbon monoxide (FAV) occurs at a time (TAV), one-half of a breathing period after the effective inspiration time (TI) for the two very different breathing patterns. T, is well-defined in relation to any breathing pattern which can be approximated by ramps and pauses. If TAV and the sample time chosen by the experimental method are known, then the measured DLCO can be corrected to the actual diffusing capacity (DL). The theory agrees with experimental results and computer simulations of inhomogeneous lungs from the literature. This agreement suggests that the theory for the homogeneous lung is also relevant to the inhomogeneous lung.

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The Measurement of the Pulmonary Diffusing Capacity in the Presence of Lung Disease

Cited by 39 publications

References 26 publications

Pulmonary Diffusing Capacity: A Comparison of Breath-Holding and Steady State Methods Using Carbon Monoxide

Pulmonary Diffusing Capacity: A Comparison of Breath-Holding and Steady State Methods Using Carbon Monoxide

Factors Influencing the Diffusing Capacity of Each Lung

Temporal Effects in the Estimation of Pulmonary Diffusing Capacity

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