Cardiac Output, Oxygen Consumption and Muscle Oxygen Delivery in Submaximal Exercise

2003 ◽  
pp. 279-284 ◽  
Author(s):  
Christopher B. Wolff
Keyword(s):  
Cardiac Output ◽  
Oxygen Consumption ◽  
Oxygen Delivery ◽  
Submaximal Exercise ◽  
Muscle Oxygen

Non-invasive Measurement of Cardiac Output and Ventricular Ejection Fractions in Chronic Cardiac Failure: Relationship to Impaired Exercise Tolerance

1997 ◽  
Vol 93 (3) ◽  
pp. 195-203 ◽  
Author(s):  
Ian C. Steele ◽  
ANN Moore ◽  
Anne-Marie Nugent ◽  
Marshall S. Riley ◽  
Norman P. S. Campbell ◽  
...  
Keyword(s):  
Cardiac Output ◽  
Oxygen Consumption ◽  
Oxygen Uptake ◽  
Cardiac Failure ◽  
Exercise Tolerance ◽  
Perceived Exertion ◽  
Lactate Concentration ◽  
Submaximal Exercise ◽  
Chronic Cardiac Failure ◽  
And Control

1. The role of cardiac output limitation in the pathophysiology of exercise in patients with chronic failure remains undefined. During steady-state submaximal exercise, oxygen uptake is similar in patients and control subjects, but it is not known if cardiac output is also similar. We wished to determine if the reduced exercise tolerance of patients with chronic cardiac failure during such exercise is related to reduced cardiac output, or to peripheral factors. 2. Ten male patients with stable chronic failure and ten age-matched male normal controls were studied at rest and during exercise. Each subject performed a familiarization exercise test, a symptom-limited maximal exercise test and two submaximal exercise tests. Cardiac output was measured by a carbon dioxide rebreathing method. We also measured oxygen consumption, ventilation, Borg score of perceived exertion and venous lactate concentration, and ejection fractions. 3. As expected, patients had lower peak oxygen consumption [median (range) 1.18 (0.98–1.76) versus 1.935 (1.53–2.31) 1/min; P < 0.001], lower peak venous lactate concentration but a similar overall level of perceived exertion. At the same submaximal workload, patients and control subjects had similar oxygen consumption [0.67 (0.59–0.80) versus 0.62 (0.52–0.82) 1/min] and cardiac output [6.92 (5.79–9.76) versus 7.3 (5.99–10.38) 1/min] but the patients had a greater perceived level of exertion [Borg score: 4 (1–6) versus 3 (1–5); P < 0.005], higher venous lactate concentration [1.6 (1–3.3) versus 1.14 (0.7–1.7) mmol/l; P < 0.05] and higher heart rate [106 (89–135) versus 87 (69–112) beats/min;P < 0.005]. 4. During submaximal exercise at a similar absolute workload, patients with cardiac failure have a similar oxygen uptake and cardiac output but greater anaerobiosis and increased fatigue when compared with normal subjects. These findings appear to relate predominantly to changes that occur in the periphery rather than abnormalities of central cardiac function.

Oxygen delivery in lambs: cardiovascular and hematologic development

1979 ◽  
Vol 237 (6) ◽  
pp. H668-H675 ◽  
Author(s):  
G. Lister ◽  
T. K. Walter ◽  
H. T. Versmold ◽  
P. R. Dallman ◽  
A. M. Rudolph
Keyword(s):  
Cardiac Output ◽  
Oxygen Consumption ◽  
Oxygen Delivery ◽  
Venous Blood ◽  
Oxygen Affinity ◽  
Fetal Hemoglobin ◽  
Hemoglobin Concentration ◽  
Mixed Venous Blood ◽  
Hemoglobin Oxygen Affinity ◽  
Very High

After birth a decrease in hemoglobin concentration occurs while high metabolic demands are imposed on the infant by the extrauterine environment. Using the resting lamb as a model, we studied the mechanisms that are called into play during this period to maintain oxygen delivery. Measurements were made of oxygen consumption, arterial and mixed venous blood oxygen contents, cardiac output, hemoglobin concentration, percent fetal hemoglobin, 2,3-diphosphoglycerate, and hemoglobin oxygen affinity during the first two postnatal months. There was a rapid decrease in hemoglobin concentration after birth and concomitant decrease in hemoglobin oxygen affinity, changes similar to those described in humans. Cardiac output and oxygen consumption were both very high immediately after birth and declined in parallel, so that arteriovenous oxygen content difference was constant. Thus at rest cardiac output varies as a result of the changing need for oxygen. This relationship is independent of hemoglobin concentration or oxygen affinity within the normal range. If, however, oxygen demands were increased, oxygen delivery might be compromised by a limited ability to increase oxygen extraction during the immediate newborn period or when hemoglobin concentration is lowest.

Measurement of Oxygen Consumption and Arterial-Venous Oxygen Saturation following Total Artificial Heart Implantation

1993 ◽  
Vol 16 (3) ◽  
pp. 135-140 ◽  
Author(s):  
P.D. Robison ◽  
G.M. Pantalos ◽  
J.W. Long ◽  
R.S. Bliss ◽  
D.K. Price ◽  
...  
Keyword(s):  
Cardiac Output ◽  
Oxygen Consumption ◽  
Oxygen Delivery ◽  
Artificial Heart ◽  
Tissue Perfusion ◽  
Oxygen Metabolism ◽  
Total Artificial Heart ◽  
Oxygen Utilization ◽  
Venous Oxygen Saturation ◽  
Mixed Venous

Current algorithms for control of the total artificial heart are directed at maintaining hemodynamic homeostasis. Future control systems will also need to modify cardiac output in response to metabolic needs. This study was undertaken to evaluate oxygen metabolism monitoring as an indicator of the adequacy of organ and tissue perfusion. Following recovery from implantation of the Utah-100 pneumatic total artificial hearts, five calves (85 to 95 kg) underwent placement of fiberoptic oxymetry catheters to determine mixed venous and arterial oxygen saturations. By continuously measuring oxygen consumption with a gas analyzer, oxygen utilization and delivery were determined. In the awake calves, at-rest cardiac output was varied to produce hyperperfused and hypoperfused conditions while the adequacy of tissue perfusion was assessed with continuous mixed venous oxymetry and confirmed with serum lactate (Lact) levels. Inadequate tissue perfusion (Lact > 1.0 mmol/L) was evidenced by a mixed venous oxygen saturation <40%, oxygen delivery of < 200.0 milliliters/minute/m2), and oxygen delivery to utilization ratio of < 1.8 during the hypoperfusion conditions of the experiment. By accounting for oxygen consumption, the ratio of oxygen delivery to oxygen utilization was predictive of the adequacy of tissue perfusion. These results suggest that continuous oxygen metabolism monitoring may be useful as a physiologic control modifier to maintain total artificial heart output sufficient to meet physiologic needs, while avoiding hyperperfusion, unnecessary wear and deterioration of the implanted device due to excessive heart rates.

Tolerance to Acute Isovolemic Hemodilution

2003 ◽  
Vol 99 (1) ◽  
pp. 97-104 ◽  
Author(s):  
Philippe Van der Linden ◽  
Stefan De Hert ◽  
Nathalie Mathieu ◽  
Françoise Degroote ◽  
Denis Schmartz ◽  
...  
Keyword(s):  
Cardiac Output ◽  
Oxygen Consumption ◽  
Oxygen Delivery ◽  
Oxygen Demand ◽  
Hemoglobin Concentration ◽  
Perioperative Period ◽  
Isovolemic Hemodilution ◽  
Anesthetic Depth ◽  
Output Response ◽  
Critical Oxygen

Background Acceptance of a lower transfusion trigger in the perioperative period requires study of the effects of anesthetic depth on the tolerance to acute isovolemic anemia. Anesthetic agents with negative effects on the cardiovascular system may exert proportionately greater depressant effects on cardiac output response than on tissue oxygen demand, reducing tolerance to acute isovolemic anemia. Methods In the first study, animals were anesthetized with halothane (n = 14; 23.8 +/- 4.8 kg, mean +/- SD). In a second study, animals were anesthetized with ketamine (n = 14; 24.3 +/- 4.7 kg). In each study, dogs were randomly allocated to receive either low or high concentrations of anesthetic. Oxygen delivery and oxygen consumption were determined from independent measurements during a stepwise isovolemic hemodilution protocol. In each dog, critical oxygen delivery was determined from a plot of oxygen consumption versus oxygen delivery using a least-sum-of-squares technique. Critical hemoglobin (hemoglobin) was determined from a plot of hemoglobin versus oxygen consumption using the same method. Results With both agents, the higher anesthetic concentration was associated with decreased oxygen consumption, resulting in a lower critical oxygen delivery. However, critical hemoglobin was significantly higher in the animals receiving the higher anesthetic dosage (1.5 vs. 1.0 minimum alveolar concentration of halothane: 4.1 +/- 1.3 vs. 2.3 +/- 0.5 g/dl, P &lt; 0.05; high- vs. low-dose ketamine: 3.7 +/- 1.4 vs. 2.5 +/- 0.6 g/dl, P &lt; 0.05). This was related to a marked blunting of the cardiac output response to hemodilution in the animals receiving the higher anesthetic dosage. Conclusions Increased anesthetic depth with halothane or ketamine resulted in a decreased tolerance to acute anemia, as reflected by a significant increase in critical hemoglobin concentration.

The Relationship between Oxygen Delivery and Consumption in the Conscious Rat before and after Expansion of Body Fluid Volumes

1984 ◽  
Vol 66 (1) ◽  
pp. 91-98 ◽  
Author(s):  
J. M. Ledingham ◽  
S. Gofford ◽  
S. J. W. Evans
Keyword(s):  
Blood Pressure ◽  
Cardiac Output ◽  
Oxygen Consumption ◽  
Sodium Chloride ◽  
Oxygen Delivery ◽  
Body Fluid ◽  
Arterial Oxygen ◽  
The Relationship ◽  
Oxygen Consumption And Delivery

1. Oxygen consumption and delivery (defined as the product of cardiac output, haemoglobin concentration and arterial oxygen saturation) and haemodynamic variables were examined in the conscious resting rat throughout the day and after the expansion of body fluid volumes. Cardiac output was measured in arbitrary units by electromagnetic flowmetry and oxygen consumption by respirometry. 2. The variability of blood pressure in the basal state was significantly less than that of cardiac output. 3. Oxygen consumption was significantly correlated with cardiac output and oxygen delivery. 4. In studies undertaken throughout the day, both oxygen consumption and delivery fell in the afternoon and there was evidence that the relationship between these two variables was curvi- rather than recti-linear. 5. During oral sodium chloride administration for 7 days, blood pressure rose and some evidence was found for an alteration in the relationship between oxygen consumption and delivery, with an excess of delivery relative to consumption, particularly on the first day of salt loading. 6. Intravenous injection of sodium chloride solution (0.171 mol/l) did not alter the relationship between oxygen consumption and delivery. 7. Expansion of blood volume, while the packed cell volume was maintained nearly constant, raised oxygen delivery transiently and evidence was obtained that the relationship between oxygen consumption and delivery was altered, with oxygen delivery rising relatively more than oxygen consumption. 8. The findings are discussed in relation to the autoregulatory hypothesis of circulatory control and for the role of autoregulation in hypertensive states. The importance of relating oxygen delivery to metabolic requirements in studies of the role of autoregulation is emphasized.

Theoretical optimization of pulmonary-to-systemic flow ratio after a bidirectional cavopulmonary anastomosis

1998 ◽  
Vol 274 (2) ◽  
pp. H694-H700 ◽  
Author(s):  
William P. Santamore ◽  
Ofer Barnea ◽  
Christopher J. Riordan ◽  
Mitchell P. Ross ◽  
Erle H. Austin
Keyword(s):  
Cardiac Output ◽  
Oxygen Consumption ◽  
Oxygen Saturation ◽  
Oxygen Delivery ◽  
Inferior Vena ◽  
Upper Body ◽  
Lower Body ◽  
Flow Ratio ◽  
Inferior Vena Caval ◽  
Cavopulmonary Anastomosis

A univentricle with parallel pulmonary and systemic circulations is inherently inefficient because mixing of pulmonary and systemic venous return occurs. Thus a cavopulmonary anastomosis is used as a staged palliative procedure to reduce volume overload in patients with cyanotic congenital heart disease. On the basis of oxygen uptake and consumption, an equation was derived that related cardiac output, pulmonary venous oxygen saturation, upper body oxygen consumption, and superior-to-inferior vena caval blood flow ratio (QSVC/QIVC) to oxygen delivery. The primary findings were as follows. 1) As QSVC/QIVCincreases, total body oxygen delivery and arterial and superior vena caval oxygen saturations increase. 2) As QSVC/QIVCincreases, lower body oxygen delivery and inferior vena caval oxygen saturation initially increase, then peak, and then decrease. 3) As the percentage of lower body oxygen consumption increases, oxygen delivery and saturation decrease. 4) A cavopulmonary anastomosis decreases the required cardiac output for a given oxygen delivery. Thus we concluded that a high systemic arterial oxygen saturation after cavopulmonary anastomosis requires a high percentage of upper body oxygen consumption and a high QSVC/QIVCand that the cavopulmonary anastomosis reduces the volume load on the single ventricle.

Determinants of VO2 max decline with aging: an integrated perspective

2008 ◽  
Vol 33 (1) ◽  
pp. 130-140 ◽  
Author(s):  
Andrew C. Betik ◽  
Russell T. Hepple
Keyword(s):  
Skeletal Muscle ◽  
Cardiac Output ◽  
Oxygen Delivery ◽  
Dominant Role ◽  
Oxidative Capacity ◽  
Oxygen Utilization ◽  
Critical Perspective ◽  
Progressive Decline ◽  
Muscle Oxygen ◽  
Capillary Bed

Aging is associated with a progressive decline in the capacity for physical activity. Central to this decline is a reduction in the maximal rate of oxygen utilization, or VO2 max. This critical perspective examines the roles played by the factors that determine the rate of muscle oxygen delivery versus those that determine the utilization of oxygen by muscle as a means of probing the reasons for VO2 max decline with aging. Reductions in muscle oxygen delivery, principally due to reduced cardiac output and perhaps also a maldistribution of cardiac output, appear to play the dominant role up until late middle age. On the other hand, there is a decline in skeletal muscle oxidative capacity with aging, due in part to mitochondrial dysfunction, which appears to play a particularly important role in extreme old age (senescence) where skeletal muscle VO2 max is observed to decline by approximately 50% even under conditions of similar oxygen delivery as young adult muscle. It is noteworthy that at least the structural aspects of the capillary bed do not appear to be reduced in a manner that would compromise the capacity for muscle oxygen diffusion even in senescence.

Cardiac output during exercise and anaerobic metabolism in man

1964 ◽  
Vol 19 (5) ◽  
pp. 839-848 ◽  
Author(s):  
H. D. Thomas ◽  
Buris Boshell ◽  
Carlos Gaos ◽  
T. J. Reeves
Keyword(s):  
Cardiac Output ◽  
Oxygen Consumption ◽  
Heart Disease ◽  
Time Course ◽  
Anaerobic Metabolism ◽  
Normal Subjects ◽  
Submaximal Exercise ◽  
Concentration Time ◽  
Rate Of Increase

The concentration time course of lactate, pyruvate, and excess lactate during 4 min of exercise and 30 min of recovery was studied in 20 patients with heart disease and in 8 normal subjects. The level of excess lactate accrued from the exercise was found to correlate well with the level of delta oxygen consumption in normal subjects ( r = .922). The cardiac output of the subjects with heart disease was considered in relation to the regression of cardiac output on oxygen consumption for normal subjects previously established by Donald (Clin. Sci. 14: 37–73, 1955). The patients with subnormal cardiac outputs during exercise had higher excess lactate values and lactate/pyruvate ratios than normal subjects and patients with normal cardiac outputs at similar levels of work. Normal subjects carrying out more severe work showed even higher concentration of excess lactate than did the patients with heart disease at lower work levels. The increase in excess lactate was maximal during the 2nd min of submaximal exercise. The rate of increase was progressively diminished during succeeding minutes. Note: (With the Assistance of James Carr and Wayne Vaughan) lactate; pyruvate; excess lactate Submitted on December 10, 1963

scholarly journals Exercise intolerance in Type 2 diabetes: is there a cardiovascular contribution?

2018 ◽  
Vol 124 (5) ◽  
pp. 1117-1139 ◽  
Author(s):  
Veronica J. Poitras ◽  
Robert W. Hudson ◽  
Michael E. Tschakovsky
Keyword(s):  
Type 2 Diabetes ◽  
Oxygen Delivery ◽  
Diabetes Management ◽  
Vascular Dysfunction ◽  
Muscle Blood Flow ◽  
Submaximal Exercise ◽  
Exercise Intolerance ◽  
Future Research ◽  
Muscle Oxygen

Physical activity is critically important for Type 2 diabetes management, yet adherence levels are poor. This might be partly due to disproportionate exercise intolerance. Submaximal exercise tolerance is highly sensitive to muscle oxygenation; impairments in exercising muscle oxygen delivery may contribute to exercise intolerance in Type 2 diabetes since there is considerable evidence for the existence of both cardiac and peripheral vascular dysfunction. While uncompromised cardiac output during submaximal exercise is consistently observed in Type 2 diabetes, it remains to be determined whether an elevated cardiac sympathetic afferent reflex could sympathetically restrain exercising muscle blood flow. Furthermore, while deficits in endothelial function are common in Type 2 diabetes and are often cited as impairing exercising muscle oxygen delivery, no direct evidence in exercise exists, and there are several other vasoregulatory mechanisms whose dysfunction could contribute. Finally, while there are findings of impaired oxygen delivery, conflicting evidence also exists. A definitive conclusion that Type 2 diabetes compromises exercising muscle oxygen delivery remains premature. We review these potentially dysfunctional mechanisms in terms of how they could impair oxygen delivery in exercise, evaluate the current literature on whether an oxygen delivery deficit is actually manifest, and correspondingly identify key directions for future research.

Cardiovascular and Metabolic Response to Acute Normovolemic Anemia

2000 ◽  
Vol 93 (4) ◽  
pp. 1011-1016 ◽  
Author(s):  
Brigitte E. Ickx ◽  
Michel Rigolet ◽  
Philippe J. Van der Linden
Keyword(s):  
Cardiac Output ◽  
Oxygen Consumption ◽  
Cardiac Index ◽  
Oxygen Delivery ◽  
Oxygen Extraction ◽  
Stroke Index ◽  
Acute Normovolemic Hemodilution ◽  
Output Response ◽  
Anesthetic Drugs ◽  
Normovolemic Hemodilution

Background The maintenance of adequate tissue oxygenation during acute anemia depends on an increase in both cardiac output and tissue oxygen extraction. This study tested the hypothesis that anesthesia blunts the cardiac output response associated with acute normovolemic hemodilution. Methods Forty patients undergoing major abdominal surgery were prospectively randomized to undergo acute normovolemic hemodilution (ANH) either awake (awake group, n = 20) or with fentanyl-nitrous oxide-isoflurane anesthesia (anesthetized group, n = 20). Radial and pulmonary artery catheters were placed in all patients. After hemodynamic measurements were taken, patients in the two groups underwent hemodilution to decrease their hemoglobin concentration from 13 to 8 g/dl. A total of 1,875 +/- 222 ml (mean +/- SD) of blood was collected and simultaneously replaced by the same volume of medium molecular weight hydroxyethylstarch in both groups. Results In the awake group, ANH resulted in a significant increase in cardiac index (from 3.1 +/- 0.5 to 4.8 +/- 1.0 l. min-1. m-2) related to both an increase in heart rate and stroke index. Oxygen delivery remained unchanged, but oxygen consumption increased significantly, resulting in an increase in oxygen extraction ratio. In the anesthetized group, ANH resulted in a significantly smaller increase in cardiac index (from 2.3 +/- 0.5 to 3.1 +/- 0.7 l. min-1. m-2) related solely to an increase in stroke index. Oxygen delivery decreased but oxygen consumption was maintained as oxygen extraction increased. Conclusions Anesthesia significantly reduces the cardiac output response associated with ANH. This could be related to the effects of the anesthetic drugs on the autonomic and the cardiovascular systems.

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