Central venous bubbles and mixed venous nitrogen in goats following decompression

1981 ◽  
Vol 51 (5) ◽  
pp. 1238-1244 ◽  
Author(s):  
B. G. D'Aoust ◽  
H. T. Swanson ◽  
R. White ◽  
R. Dunford ◽  
J. Mahoney
Keyword(s):  
Cardiac Output ◽  
Venous Blood ◽  
Bubble Formation ◽  
Inert Gas ◽  
Mixed Venous Blood ◽  
Central Venous ◽  
Output Measurement ◽  
General Response ◽  
Nitrogen Elimination ◽  
Mixed Venous

Decompression of awake goats from saturation at 1, 2, and 3 ATA of air has been carried out using ultrasonic Doppler bubble detection, central venous blood inert gas measurement, and cardiac output measurement. The results of these experiments indicate that the decrease in nitrogen elimination rate as an apparent result of decompression cannot be due to excessive cardiac output or mass transport of a large amount of inert gas to the lungs as bubbles. Rather, the rapid drop in mixed venous nitrogen content is consistent with a generalized decrease in tissue-to-blood nitrogen elimination. This in turn appears to be due to a cardiovascular response to the decompression insult as was previously reported for dogs (D'Aoust et al., J. Appl. Physiol. 41: 348--355, 1976) at 1, 2, and 3 ATA; addition of ultrasonic Doppler monitoring and cardiac output in the present studies allowed measurement of the degree of latency in the appearance of bubbles at a central venous location. This time period includes that required for bubble formation, growth, and vascular transport of the bubbles to the Doppler detector. All results of these studies are consistent with the interpretation that due to a decompression insult, which probably includes bubble formation, some degree of hemostasis, and other hematologic sequelae, the transport of tissue inert gas to the capillary venous blood is retarded, thus providing the rapid apparent decrease in mixed venous blood inert gas content. These results demonstrate what is most likely a general response to a severe but not crucial decompression by the cardiovascular system.

Respiratory measurements of cardiac output: from elegant idea to useful test

2004 ◽  
Vol 96 (2) ◽  
pp. 428-437 ◽  
Author(s):  
Gabriel Laszlo
Keyword(s):  
Cardiac Output ◽  
Human Subjects ◽  
Venous Blood ◽  
The Body ◽  
Mixed Venous Blood ◽  
Indirect Determination ◽  
Arterial Blood ◽  
Pulmonary Capillary ◽  
Pulmonary Arterial ◽  
Mixed Venous

The measurement of cardiac output was first proposed by Fick, who published his equation in 1870. Fick's calculation called for the measurement of the contents of oxygen or CO2 in pulmonary arterial and systemic arterial blood. These values could not be determined directly in human subjects until the acceptance of cardiac catheterization as a clinical procedure in 1940. In the meanwhile, several attempts were made to perfect respiratory methods for the indirect determination of blood-gas contents by respiratory techniques that yielded estimates of the mixed venous and pulmonary capillary gas pressures. The immediate uptake of nonresident gases can be used in a similar way to calculate cardiac output, with the added advantage that they are absent from the mixed venous blood. The fact that these procedures are safe and relatively nonintrusive makes them attractive to physiologists, pharmacologists, and sports scientists as well as to clinicians concerned with the physiopathology of the heart and lung. This paper outlines the development of these techniques, with a discussion of some of the ways in which they stimulated research into the transport of gases in the body through the alveolar membrane.

Estimation of ventilation-perfusion inequality by inert gas elimination without arterial sampling

1985 ◽  
Vol 59 (2) ◽  
pp. 376-383 ◽  
Author(s):  
P. D. Wagner ◽  
C. M. Smith ◽  
N. J. Davies ◽  
R. D. McEvoy ◽  
G. E. Gale
Keyword(s):  
Cardiac Output ◽  
Venous Blood ◽  
Inert Gas ◽  
Chronic Obstructive ◽  
Obstructive Pulmonary Disease ◽  
Arterial Access ◽  
Arterial Blood ◽  
Potential Applications ◽  
Clinical Interest ◽  
Mixed Venous

Estimation of ventilation-perfusion (VA/Q) inequality by the multiple inert gas elimination technique requires knowledge of arterial, mixed venous, and mixed expired concentrations of six gases. Until now, arterial concentrations have been directly measured and mixed venous levels either measured or calculated by mass balance if cardiac output was known. Because potential applications of the method involve measurements over several days, we wished to determine whether inert gas levels in peripheral venous blood ever reached those in arterial blood, thus providing an essentially noninvasive approach to measuring VA/Q mismatch that could be frequently repeated. In 10 outpatients with chronic obstructive pulmonary disease, we compared radial artery (Pa) and peripheral vein (Pven) levels of the six gases over a 90-min period of infusion of the gases into a contralateral forearm vein. We found Pven reached 90% of Pa by approximately 50 min and 95% of Pa by 90 min. More importantly, the coefficient of variation at 50 min was approximately 10% and at 90 min 5%, demonstrating acceptable intersubject agreement by 90 min. Since cardiac output is not available without arterial access, we also examined the consequences of assuming values for this variable in calculating mixed venous levels. We conclude that VA/Q features of considerable clinical interest can be reliably identified by this essentially noninvasive approach under resting conditions stable over a period of 1.5 h.

Influence of changes in cardiac output on the acid-base status of arterial and mixed venous blood

1987 ◽  
Vol 410 (3) ◽  
pp. 257-262 ◽  
Author(s):  
Y. L. Hoogeveen ◽  
J. P. Zock ◽  
P. Rispens ◽  
W. G. Zijlstra
Keyword(s):  
Cardiac Output ◽  
Venous Blood ◽  
Mixed Venous Blood ◽  
Acid Base ◽  
Acid Base Status ◽  
Mixed Venous

Lactate, pyruvate, glucose, and free fatty acid in mixed venous and arterial blood

1963 ◽  
Vol 18 (5) ◽  
pp. 933-936 ◽  
Author(s):  
P. Harris ◽  
T. Bailey ◽  
M. Bateman ◽  
M. G. Fitzgerald ◽  
J. Gloster ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Cardiac Output ◽  
Fatty Acid ◽  
Free Fatty Acid ◽  
Venous Blood ◽  
Average Concentration ◽  
Mixed Venous Blood ◽  
Arterial Blood ◽  
Acquired Heart Disease ◽  
Mixed Venous

The concentrations of lactic acid, pyruvic acid, glucose, and free fatty acids have been measured simultaneously in the blood from the pulmonary and brachial arteries at rest and during exercise in a group of patients with acquired heart disease. The arteriovenous differences in the concentration of lactate, pyruvate, and free fatty acid were such as could be attributed to chance. The average concentration of glucose was slightly but significantly higher in the brachial arterial blood than in the mixed venous blood. cardiac output; lung metabolism; exercise Submitted on January 15, 1963

Physiological evidence for the occurrence of pathways shunting blood away from the secondary lamellae of eel gills

1982 ◽  
Vol 98 (1) ◽  
pp. 277-288
Author(s):  
G. M. Hughes ◽  
C. Peyraud ◽  
M. Peyraud-Waitzenegger ◽  
P. Soulier
Keyword(s):  
Cardiac Output ◽  
Venous Blood ◽  
Mixed Venous Blood ◽  
Intravenous Injections ◽  
Fick Principle ◽  
Secondary Lamellae ◽  
Circulatory Change ◽  
Before And After ◽  
Gill Filaments ◽  
Mixed Venous

1. Several cardiovascular and respiratory measurements have been performed in eels before and after intravenous injections of adrenaline. These experiments have allowed a comparison to be made of values for the cardiac output determined directly (Q) and using the Fick principle (QF) on individual fish under these two conditions. 2. Under control conditions it was shown that QF/Q = 0.72, indicating that about 30% of the mixed venous blood afferent to the gills is returned directly to the heart and bypasses the lamellar circulation via veno-venous anastomoses between the afferent filament arteries and the central venous space of the gill filaments. 3. Adrenaline, which during winter only has its action due to stimulation of alpha-adrenoreceptors, induced a hypoventilation but no changes in cardiac output in spite of a bradycardia. The oxygen content of the mixed venous blood was markedly increased whereas Ca,O2 remained unchanged as did the percentage utilization of oxygen from the water as it passed over the gills. The efferent blood flow from the gills after injection of adrenaline was almost equal to the total cardiac output. It is suggested that such a circulatory change was due to adrenaline-mediated constriction of veno-venous anastomoses in the gills of the eel.

Central venous to mixed venous blood oxygen and lactate gradients are associated with outcome in critically ill patients

2008 ◽  
Vol 34 (9) ◽  
pp. 1662-1668 ◽  
Author(s):  
Guillermo Gutierrez ◽  
Pablo Comignani ◽  
Luis Huespe ◽  
F. Javier Hurtado ◽  
Arnaldo Dubin ◽  
...  
Keyword(s):  
Critically Ill ◽  
Critically Ill Patients ◽  
Venous Blood ◽  
Mixed Venous Blood ◽  
Blood Oxygen ◽  
Central Venous ◽  
Mixed Venous

scholarly journals Indirect calorimetry can be used to measure cardiac output in septic patients?

2008 ◽  
Vol 23 (suppl 1) ◽  
pp. 118-125 ◽  
Author(s):  
Maria Auxiliadora Martins ◽  
Francisco Antônio Coletto ◽  
Antônio Dorival Campos ◽  
Anibal Basile-Filho
Keyword(s):  
Intensive Care Unit ◽  
Cardiac Output ◽  
Indirect Calorimetry ◽  
Venous Blood ◽  
Correlation Coefficients ◽  
University Hospital ◽  
Parallel Analysis ◽  
Monitoring Systems ◽  
Mixed Venous Blood ◽  
Mixed Venous

PURPOSE: The aim of this study was to compare two different cardiac output (CO) monitoring systems based on the thermodilution principle (Thermo-CO) and indirect calorimetry (Fick mixed-CO) in septic patients. METHODS: Prospective study in septic patients admitted in an intensive care unit of a university hospital. Nineteen patients aged on average 45.4 ± 21.5 years were enrolled in the study. Four series of hourly measurements by the two techniques were carried out simultaneously. RESULTS: No significant differences were observed between Thermo-CO and Fick mixed-CO (7.0 ± 1.8 L.min-1 and 6.4 ± 1.7 L.min-1.). Parallel analysis of Fick mixed-CO and Fick atrial-CO was performed introducing a correction factor for the eight atrial samples in order to adjust the values of oxygen saturation obtained from atrial blood (Fick corrected atrial-CO) to those obtained from mixed venous blood. No significant differences could be detected between Fick mixed-CO and Fick corrected atrial-CO. The correlation coefficients of Thermo CO/Fick mixed-CO and Fick mixed-CO/Fick corrected atrial-CO were 0.84 and 0.94, respectively. CONCLUSION: We observed that the agreement between the two methods was satisfactory on the basis of the decisions made for treatment. Indirect calorimetry is useful to measure CO in patients with septic shock.

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