A Standardized Breath Holding Technique for the Clinical Measurement of the Diffusing Capacity of the Lung for Carbon Monoxide 1

Abstract

Previous publications from this laboratory have described (1, 2) a modification of the Krogh breath holding technique for measuring the pulmonary diffusing capacity for carbon monoxide (DL).6 This test can be performed quickly and simply and does not require arterial blood analyses. It has recently (2) been shown to provide an index of pulmonary diffusing capacity similar to that given by the DLo2 method of Lilienthal, Riley, Proemmel, and Franke (3) and the "steady state" method of Filley, MacIntosh, and Wright (4). 6 Since the combination of CO with intracellular hemoglobin occurs at a rate that offers an appreciable, and under some conditions the major, part of the resistance to the uptake of CO in the lungs (5, 6) it is desirable to distinguish between the "true" diffusing capacity, or that of the pulmonary capillary membrane alone (D.), and the apparent diffusing capacity of the whole lung (DL). These are related by the equation 1/DL = I/D. + I/)Vc where j is the rate of combination of CO with intracorpuscular hemoglobin in ml. per min. per mm. Hg CO tension per ml. blood, and Vo is the volume of blood in the pulmonary capillaries at any instant. 0 decreases as 0 tension increases (7), causing DL to decrease, since D.and Ve are presumably relatively independent of alveolar 0, tension (8). Normally a further subscript of CO or Q, would be used to indicate the gas to which the measurement applies. However, in this article, which is mainly concerned with CO, the subscript is omitted and can be assumed to be "CO" unless otherwise stated. normal values of DL as well as values in patients with various chest diseases. METHODSThe technique for the measurement of DL, which has been reported be'fore (1, 2), consists essentially of having the subject make a maximal inspiration of a gas mixture containing 10 per cent helium (He), 0.3 per cent CO and approximately 21 per cent 02 in N2 from the level of his residual volume, hold it for a measured time, and then rapidly expire. All of this expiration except the first liter is collected in a bag by the operator and analyzed as alveolar gas. The CO concentration which was present in this sample before any CO The apparatus used for the test is illustrated in Figure 1. It differs from that reported previously (1, 2) mainly in its greater simplicity; in these previous communications the expired alveolar He and/or CO concentrations were measured at the mouth by recording analytical instruments. The circuit is closed, permitting inspiration from the bag of the Donald-Christie apparatus and expiration into the space around the bag, a spirometer recording the change in respiratory volumes. Tap (A) is used by the operator for collecting the expired alveolar sample. Since the gas mixture is inspired from the level

Relation between abnormalities in the chest radiograph and changes in pulmonary function in chronic bronchitis and emphysema

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TGF-β1 Variants in Chronic Beryllium Disease and Sarcoidosis

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A Study of the Mechanism by Which Exercise Increases the Pulmonary Diffusing Capacity for Carbon Monoxide

“…Hg. Ogilvie, Forster, Blakemore and Morton reported comparable results in a similar study (5). in the other studies where pH was determined in conjunction with the breath holding DL, the arterial blood sample for pH determination was withdrawn from the indwelling arterial needle over the entire 10 second breath holding period.…”