Die alveol�r-arterielle Sauerstoffdruckdifferenz und das Problem des Gasaustausches in der menschlichen Lunge

Bartels, H.; Rodewald, G.

doi:10.1007/bf00363457

Cited by 50 publications

(6 citation statements)

References 15 publications

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“…In such subjects the pulmonary arteriovenous shunt-flow is known to be minimal (7)(8)(9), and, as expected, the curves approximated straight lines.…”

Section: Q Qpsupporting

confidence: 77%

Estimation of Pulmonary Arteriovenous Shunt-Flow Using Intravenous Injections of T-1824 Dye and Kr85*

Fritts¹,

Hardewig²,

Rochester³

et al. 1960

J. Clin. Invest.

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“…In such subjects the pulmonary arteriovenous shunt-flow is known to be minimal (7)(8)(9), and, as expected, the curves approximated straight lines.…”

Section: Q Qpsupporting

confidence: 77%

Estimation of Pulmonary Arteriovenous Shunt-Flow Using Intravenous Injections of T-1824 Dye and Kr85*

Fritts¹,

Hardewig²,

Rochester³

et al. 1960

J. Clin. Invest.

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“…Any Po2 gradient due to diffusion difficulty becomes infinitesimal at this time when Po2 is high in all alveoli (13)(14)(15). Alveolar and end-capillary oxygen tensions are thus identical within a region; i.e., PAI = Pi, PA2 =P2.…”

Section: Theorymentioning

confidence: 99%

The Determination of Uneven Pulmonary Blood Flow From the Arterial Oxygen Tension During Nitrogen Washout

Finley¹

1961

J. Clin. Invest.

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Many tests are available for measuring unevenness of pulmonary ventilation. In recent years tests of unevenness of pulmonary blood flow have been described, which utilize radioactive krypton (1) in patients with emphysema, radioactive oxygen in patients with mitral stenosis (2), and radioactive carbon dioxide in normal subjects (3). These studies provide quantitative data on the degree of unevenness of pulmonary blood flow but require expensive and complicated apparatus and are not easily adapted to clinical pulmonary function testing. Simpler methods of estimating unevenness of blood flow in relation to ventilation have been suggested. These are based on the rate of rise of arterial oxygen saturation (ear oximeter) during the inhalation of oxygen (4-6), analysis of gas samples obtained from various lobes of the lungs (7), continuous analysis of a single expiration (8), and the difference between the nitrogen tension of alveolar gas and urine (9, 10). These simpler methods do not provide quantitative data on the degree of unevenness of pulmonary blood flow.An ingenious graphical method of determining unevenness of perfusion of the lung in patients with chronic pulmonary emphysema has been worked out by Briscoe and co-workers (11). This method utilizes a nitrogen washout and wash-in technique and the arterial saturation (luring air-breathing. Its disadvantage is that other causes of arterial desaturation i.e., shunts and diffusion barriers cause an overestimation of the degree of unevenness of perfusion.In this laboratory we have devised a test which yields quantitative data for the determination of the fractional alveolar ventilation and pulmonary capillary blood flow that go to the well and poorly ventilated regions of the distribution of pulmonary blood flow to these regions and the anatomical shunts. The theory, method and results of these studies in normal subjects and in patients with cardiac and pulmonary disease are presented here. THEORYThe lungs can be divided into a well ventilated region (which need not be homogeneous) and a poorly ventilated region (subscripts 1 and 2, respectively). Arterial blood is a mixture of blood that has passed through these regions or through venous-to-arterial shunts. Its oxygen content (Ca) is related to the blood flows through the capillaries of the various regions (Q1, Q2) and through the shunt (Q8), and to their respective oxygen contents (Cl, C2 and Cv) as follows:Ca QT = C1 Q1 + C2Q2 + CQ9 [1] where Qi + Q2 + Qs = QT, the cardiac output. In this and subsequent formulations we omit, from our otherwise conventional (12) symbolization, the subscript c for capillary and the chemical subscript 02-It follows from Equation 1 that at any time (t) during the N2 washout:[2]Wre assume the following are constant in the later stages of the N2 washout: 1) the magnitude of the various blood flOwS (QI, Q2, Q., QT) relative to each other; 2) the arteriov5eiious 02) content difference (Ca -Cv). When we then 1 727(C. C.,) t -. 0.1.Ql + Q2

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“…Increased PA,°-Pa ko difference could be attributed to the effects of either the limitation of diffusion of gases, or increased venous admixture. It is unlikely that diffusion limitation contributes appreciably to the condition because the high 02 tension usually inspired during gaseous anaesthesia does not alleviate the hypoxaemia (Bartels & Rodewald, 1953). The condition may be exacerbated by low cardiac output, but cannot be initiated by it.…”

Section: Introductionmentioning

confidence: 99%

Changes in Blood Flow Distribution in Equine Lungs Induced by Anaesthesia

et al. 1985

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SUMMARYThe distribution of blood flow to the lungs was measured with labelled microspheres injected into horses before and during anaesthesia. Anaesthesia was induced with glycerol guaiacolate ether and ketamine, and maintained with the spontaneous breathing of halothane in oxygen. In a preliminary group of six horses, flow distribution was observed during anaesthesia in sternal, dorsal and right lateral recumbency. In two other groups, each of four horses, the flow distribution with time during either sternal or right lateral recumbency was observed. A small, constant proportion of the 15 /tm diameter microspheres bypassed the lungs. No increase in shunting with anaesthesia was detected. Blood flow distributed predominantly cranioventrally in the conscious horse in concordance with the expected effects of hydrostatic forces within the lung. In the anaesthetized horse a stable distribution rapidly developed whereby the flow was directed preferentially caudodorsally and evenly divided between the left and right lungs regardless of whether the horse was on its back, side or sternum. We conclude that an unidentified factor overrides gravitational effects on perfusion in the anaesthetized horse. If under anaesthesia, ventilation were distributed according to gravity, hypoxia would arise from this disassociation of ventilation from perfusion. The hypoxia would be most intense in dorsal recumbency, and least intense in sternal recumbency. This was reflected in the degree of hypoxaemia observed. A small but significant change in flow distribution with the phase of the respiratory cycle was detected in the conscious, standing horse.

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Die alveol�r-arterielle Sauerstoffdruckdifferenz und das Problem des Gasaustausches in der menschlichen Lunge

Cited by 50 publications

References 15 publications

Estimation of Pulmonary Arteriovenous Shunt-Flow Using Intravenous Injections of T-1824 Dye and Kr85*

Estimation of Pulmonary Arteriovenous Shunt-Flow Using Intravenous Injections of T-1824 Dye and Kr85*

The Determination of Uneven Pulmonary Blood Flow From the Arterial Oxygen Tension During Nitrogen Washout

Changes in Blood Flow Distribution in Equine Lungs Induced by Anaesthesia

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