DELAY OF BLOOD IN PASSING THROUGH THE LUNGS AS AN OBSTACLE TO THE DETERMINATION OF THE CO2 TENSION OF THE MIXED VENOUS BLOOD

1927 ◽  
Vol 82 (3) ◽  
pp. 656-664 ◽  
Author(s):  
W. F. Hamilton ◽  
J. W. Moore ◽  
J. M. Kinsman
Keyword(s):  
Venous Blood ◽  
Mixed Venous Blood ◽  
Mixed Venous

On the determination of turnover in vivo with tracers

1992 ◽  
Vol 263 (3) ◽  
pp. E417-E424
Author(s):  
J. Katz
Keyword(s):  
Specific Activity ◽  
Venous Blood ◽  
Vena Cava ◽  
Whole Body ◽  
Mixed Venous Blood ◽  
Close Approximation ◽  
High Turnover ◽  
The Right ◽  
Mixed Venous

Theoretical and practical aspects of the application of tracer methods for the measurement of turnover of blood-borne compounds are discussed, with special regard to lactate. The validity of the application of the tracer into the aortic arch and sampling from the right atrium (A-V), the administration of tracer into the vena cava and sampling from the aorta (V-A), and sampling to the determination of turnover are examined, using numerical examples. It is shown that the difference between specific activity in arterial and mixed venous blood depends mainly on the cardiac output, the ratio of tracee turnover to the mass of circulating tracee, and the sites of production and utilization of the tracee. Conditions are shown under which the A-V and V-A modes overestimate or underestimate the true rate of turnover. In theory, the A-V mode provides an exact estimate of turnover when the mean specific activity of the tracee in the whole body equals the specific activity of mixed venous blood in the right heart. It is shown that, for compounds with a high turnover rate, the underestimate in the A-V mode is small, and the mode provides a close approximation of true turnover. The underestimate in the V-A mode at high turnover rates is extensive. Experimental evidence indicates that, in several animal species, the specific activity of lactate and several amino acids in several organs and tissues nearly equals that in the venous blood, with the A-V mode providing a close approximation of the true turnover for these compounds.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of cocaine on incremental treadmill exercise in horses

1993 ◽  
Vol 75 (6) ◽  
pp. 2727-2733 ◽  
Author(s):  
K. H. McKeever ◽  
K. W. Hinchcliff ◽  
D. F. Gerken ◽  
R. A. Sams
Keyword(s):  
Right Ventricular ◽  
Blood Lactate ◽  
Venous Blood ◽  
Lactate Concentration ◽  
Blood Lactate Concentration ◽  
Ventricular Pressure ◽  
Mixed Venous Blood ◽  
Work Intensity ◽  
Venous Blood Lactate ◽  
Mixed Venous

Four mature horses were used to test the effects of two doses (50 and 200 mg) of intravenously administered cocaine on hemodynamics and selected indexes of performance [maximal heart rate (HRmax), treadmill velocity at HRmax, treadmill velocity needed to produce a blood lactate concentration of 4 mmol/l, maximal mixed venous blood lactate concentration, maximal treadmill work intensity, and test duration] measured during an incremental treadmill test. Both doses of cocaine increased HRmax approximately 7% (P < 0.05). Mean arterial pressure was 30 mmHg greater (P < 0.05) during the 4- to 7-m/s steps of the exercise test in the 200-mg trial. Neither dose of cocaine had an effect on the responses to exertion of right atrial pressure, right ventricular pressure, or maximal change in right ventricular pressure over time. Maximal mixed venous blood lactate concentration increased 41% (P < 0.05) with the 50-mg dose and 75% (P < 0.05) with the 200-mg dose during exercise. Administration of cocaine resulted in decreases (P < 0.05) in the treadmill velocity needed to produce a blood lactate concentration of 4 mmol/l from 6.9 +/- 0.5 and 6.8 +/- 0.9 m/s during the control trials to 4.4 +/- 0.1 m/s during the 200-mg cocaine trial. Cocaine did not alter maximal treadmill work intensity (P > 0.05); however, time to exhaustion increased by approximately 92 s (15%; P < 0.05) during the 200-mg trial.(ABSTRACT TRUNCATED AT 250 WORDS)

Pulmonary diffusion in the dog lung

1962 ◽  
Vol 17 (6) ◽  
pp. 885-892 ◽  
Author(s):  
Albert H. Niden ◽  
Charles Mittman ◽  
Benjamin Burrows
Keyword(s):  
Carbon Monoxide ◽  
Pulmonary Artery ◽  
Experimental Animal ◽  
Venous Blood ◽  
Whole Body ◽  
Mixed Venous Blood ◽  
Pulmonary Diffusion ◽  
Perfused Lung ◽  
Pulmonary Arterial ◽  
Mixed Venous

Methods have been presented for assessing pulmonary diffusion by the “equilibration technique” in the experimental intact dog and perfused lung while controlling ventilation with a whole body respirator. No significant change in diffusion of carbon monoxide was noted between open and closed chest anesthetized animals, with duration of anesthesia in the intact dog, or with duration of perfusion of the isolated dog's lung. There was no demonstrable difference in diffusion when arterialized blood was used as the perfusate in place of mixed venous blood in the lung perfusions suggesting that within the range studied the Po2, Pco2, and pH of pulmonary artery blood does not directly affect the diffusion of carbon monoxide. Retrograde perfusions of dogs' lungs did not significantly alter diffusion, suggesting that pulmonary venous resistance was not significantly lower than pulmonary arterial resistance in the perfused dog lung at the flows and pressures studied. The equilibration technique for measuring pulmonary diffusion and assessing the uniformity of diffusion was well suited to the study of pulmonary diffusing characteristics in the experimental animal. Submitted on January 8, 1962

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