Carbon Dioxide and Oxygen Tensions of the Mixed Venous Blood of Man at Rest

Richards, Dickinson W.; Strauss, Marjorie L.

doi:10.1172/jci100318

Cited by 8 publications

(6 citation statements)

References 19 publications

(36 reference statements)

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“…The apparatus and technique were essentially the same as those employed by Richards and Strauss (6). A diagram is shown in Figure 1.…”

Section: Methodsmentioning

confidence: 99%

“…Duplicate analyses of the CO2 and oxygen contents of the whole blood were made using the Van Slyke-Neill apparatus. One point (occasionally two) on the C02 dissociation curve of oxygenated blood was determined, the technique of equilibration being essentially that of Austin, Van Slyke, et al (7) with a few modifications (8,6). Blood was equilibrated in a water bath for 20 minutes at 37.2°C., duplicate analyses of C02 and oxygen contents of blood and gas phases of the system then made.…”

Section: Methodsmentioning

confidence: 99%

“…Most workers have been able to demonstrate an equilibrium of CO2 tensions by similar rebreathing technique; Hamilton, Moore and Kinsman (5), however, were unable to establish equilibrium or " plateau " levels of CO2 during rebreathing in experiments with a small number of subjects. Richards and Strauss (6) in 1930 reviewed the numerous assumptions made in various rebreathing methods for estimating the values of the gases of the mixed venous blood. They showed experimentally that the same equilibria or " plateau " levels of CO2 tension of oxygenated mixed venous blood could be regularly obtained in a normal subject after 15 to 20 seconds of rebreathing, with the use of initial mixtures in the rebreathing bag which differed in CO2 tensions by 10 mm.…”

mentioning

confidence: 99%

“…The chief reason for our choice of method was the results of Richards and Strauss (6), who demonstrated both on theoretical and experimental grounds, in normal subjects, the difficulty of securing adequate equilibrium of rebreathed gases, with respect to oxygen. Presumably this difficulty would be increased in subjects with disturbed pulmonary function.…”

mentioning

confidence: 99%

“…An important assumption should perhaps be mentioned, which is made both by methods employing the Fick-principle and by most methods using inhalation of a foreign gas (6,12); namely, that any change in blood flow produced by the hyperventilation of rebreathing, does not measurably affect the arteriovenous differences of oxygen or CO2 within the time during which rebreathing takes place.…”

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confidence: 99%

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Applicability of Rebreathing Method for Determining Mixed Venous Co2 in Cases of Chronic Pulmonary Disease

Richards¹,

Cournand²,

Bryan³

1935

J. Clin. Invest.

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The carbon dioxide tension of oxygenated mixed venous blood has long been used, in normal individuals and frequently in subjects with various forms of disease, in the determination of cardiac output according to the Fick principle. The method of rebreathing mixtures of CO2 and oxygen, for establishing equilibrium between the CO2 tensions of the lungs and the incoming venous blood, and at the same time oxygenating this blood, was first described by Christiansen, Douglas and Haldane (1); later by Henderson and Prince (2) and others. In 1922 Douglas and Haldane (3) showed that the same arteriovenous differences in CO2 content were obtained in a given subject, whether the rebreathing procedure equilibrated CO2 tensions only and oxygenated the blood in the lungs, or whether this procedure equilibrated simultaneously both CO2 and oxygen tensions of incoming venous blood with the rebreathed air. Field, Bock, Gildea, and Lathrop (4) showed that arterial blood drawn during the course of rebreathing a mixture of 6 per cent CO2 and 94 per cent oxygen was fully oxygenated, and that the CO2 tensions in arterial blood and in the rebreathed air were the same. Most workers have been able to demonstrate an equilibrium of CO2 tensions by similar rebreathing technique; Hamilton, Moore and Kinsman (5), however, were unable to establish equilibrium or " plateau " levels of CO2 during rebreathing in experiments with a small number of subjects. Richards and Strauss (6) in 1930 reviewed the numerous assumptions made in various rebreathing methods for estimating the values of the gases of the mixed venous blood. They showed experimentally that the same equilibria or " plateau " levels of CO2 tension of oxygenated mixed venous blood could be regularly obtained in a normal subject after 15 to 20 seconds of rebreathing, with the use of initial mixtures in the rebreathing bag which differed in CO2 tensions by 10 mm. or more. By constructing a nomogram of the subject's blood, and by plotting on this nomogram the CO2 tensions (as obtained by rebreathing) of (a) oxygenated and (b) true mixed venous blood, these authors found that the (a) and (b) CO2 tensions represented approximately the same CO2 content of the blood.

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“…The apparatus and technique were essentially the same as those employed by Richards and Strauss (6). A diagram is shown in Figure 1.…”

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%

mentioning

confidence: 99%