Differences between directly measured and calculated values for cardiac output in the dogfish: a criticism of the Fick method

1982 ◽  
Vol 99 (1) ◽  
pp. 255-268
Author(s):  
J. D. Metcalfe ◽  
P. J. Butler
Keyword(s):  
Cardiac Output ◽  
Oxygen Uptake ◽  
Stroke Volume ◽  
Complete Control ◽  
Fick Principle ◽  
Scyliorhinus Canicula ◽  
Respiratory Surface ◽  
Significant Difference ◽  
Cardiac Bypass ◽  
Cardiac Stroke Volume

Cardiac output has been measured directly, and calculated by the Fick method, during normoxia and hypoxia in six artificially perfused dogfish (Scyliorhinus canicula) in an attempt to estimate the accuracy of this method in fish. The construction and operation of a simple extra-corporeal cardiac bypass pump is described. This pump closely mimics the flow pulse profiles of the fish's own heart and allows complete control of both cardiac stroke volume and systolic and diastolic periods. During normoxia (PO2 = 21 kPa) there was no significant difference between directly measured and calculated values for cardiac output. However, some shunting of blood past the respiratory surface of the gills may have been obscured by cutaneous oxygen uptake. In response to hypoxia (PO2 = 8.6 kPa) there is either a decrease in the amount of blood being shunted past the respiratory surface of the gills and/or an increase in cutaneous oxygen uptake such that the Fick calculated value for cardiac output is on average 38% greater than the measured value. It is proposed that the increase in the levels of circulating catecholamines that is reported to occur in response to hypoxia in this species may play an important role in the observed response to hypoxia. The results are discussed in terms of their implications for the calculation of cardiac output by the Fick principle in fish.

The effect of progressive hypoxia on respiration in the dogfish (scyliorhinus canicula) at different seasonal temperatures

1975 ◽  
Vol 63 (1) ◽  
pp. 117-130 ◽  
Author(s):  
P. J. Butler ◽  
E. W. Taylor
Keyword(s):  
Heart Rate ◽  
Cardiac Output ◽  
Oxygen Uptake ◽  
Stroke Volume ◽  
Oxygen Tension ◽  
Acclimation Temperature ◽  
Critical Oxygen Tension ◽  
Critical Oxygen ◽  
Progressive Hypoxia ◽  
Cardiac Stroke Volume

1. Dogfish were acclimated to 7, 12 or 17 degrees C and exposed to progressive hypoxia at the temperature to which they had been acclimated. During normoxia, the Q10 values for oxygen uptake, heart rate, cardiac output and respiratory frequency over the full 10 degrees C range were: 2.1, 2.1, 2.1 and 2.5 respectively. Increased acclimation temperature had no effect on cardiac stroke volume or systemic vascular resistance, although there was a decrease in branchial vascular resistance, pHa and pHv. 2. Progressive hypoxia had no effect on heart rate or oxygen uptake at 7 degrees C, whereas at 12 degrees C and 17 degrees C there was bradycardia, and a reduction in O2 uptake, with the critical oxygen tension for both variables being higher at the higher temperature. Cardiac stroke volume increased during hypoxia at each temperature, such that cardiac output did not change significantly at 12 and 17 degrees C. Neither pHa nor pHv changed significantly during hypoxia at any of the three temperatures. 3. The influence of acclimation temperatures on experimental results from poikilotherms is pointed out. Previously-published results show quantitative differences. 4. The significance of the present results with respect to the functioning and location of oxygen receptors is discussed. It is argued that as the metabolic demand and critical oxygen tension of the whole animal are increased at high acclimation temperatures the same must be the case with the oxygen receptor. This would raise the stimulation threshold and could account for the bradycardia seen during hypoxia becoming manifest at higher values of PI,O2, Pa,O2 and Pv,O2 as the acclimation temperature is raised.

Circulation, oxygen transport, and activity in the crayfish

1981 ◽  
Vol 240 (1) ◽  
pp. R99-R105 ◽  
Author(s):  
P. S. Rutledge
Keyword(s):  
Cardiac Output ◽  
Oxygen Uptake ◽  
Stroke Volume ◽  
Oxygen Transport ◽  
Uptake Rate ◽  
Oxygen Uptake Rate ◽  
Maximum Activity ◽  
Active Oxygen ◽  
Routine Activity ◽  
Fick Principle

Heart and ventilation frequencies, oxygen uptake rate, hemocyanin concentration, and pre- and postbranchial PO2 and pH were measured in unrestrained crayfish (Pacifastacus leniuculus) immediately following routine and forced (maximum) activity. Experiments were performed at 20 degrees C, the temperature of maximum scope for activity in this species, and at 10 and 25 degrees C. A procedure for using N-ethylmaleimide as an anticoagulant in hemolymph sampling is described. Hemocyanin oxygen saturation, oxygen content of pre- and postbranchial hemolymph, cardiac output, and stroke volume were estimated from the measured parameters. PO2 of postbranchial hemolymph sampled immediately after routine activity was low (9-12 Torr), accompanied by hemocyanin oxygen saturations of 55-75%. Maximum forced activity for 10 min caused further reduction in these values. Thus hemocyanin is apparently not usually saturated with oxygen in these crayfish. Cardiac output, as estimated by the Fick principle, was high (at 20 degrees C, 236 ml x kg-1 x min-1 for routine activity and 969 ml x kg-1 x min-1 for forced activity). Evidence is presented that ventilation, rather than circulation, limits active oxygen uptake and scope for activity both above and below 20 degrees C.

Respiratory and Cardiac Performance in Lolliguncula Brevis (Cephalopoda, Myopsida): The Effects of Activity, Temperature and Hypoxia

1988 ◽  
Vol 138 (1) ◽  
pp. 17-36 ◽  
Author(s):  
M.J. WELLS ◽  
R. T. HANLON ◽  
P. G. LEE ◽  
F. P. DIMARCO
Keyword(s):  
Cardiac Output ◽  
Oxygen Uptake ◽  
Stroke Volume ◽  
Acute Hypoxia ◽  
Ventilation Rate ◽  
Necessary Condition ◽  
Jet Propulsion ◽  
Q10 Values ◽  
Oxygen Carrying Capacity ◽  
Lolliguncula Brevis

Lolliguncula brevis Blainville is a small euryhaline squid found at temperatures between 11 and 31 °C. Changes in VO2, heartbeat and ventilation frequencies were observed throughout this temperature range and under a variety of conditions, including acute hypoxia and swimming by jet propulsion in a tunnel respirometer. Resting VO2 showed a Q10 of 1.47, and heart rate and ventilation rate Q10 values of 1.92 and 1.73, respectively; oxygen uptake could exceed 1.01kg−1h−1 at 30°C even at rest. The squids regulated their oxygen uptake at all temperatures. Oxygen extraction rates were in the region of 5–10% in saturated water, increasing to 15–20% in hypoxic water or after exercise. One effect of this variability is that ventilation stroke volume can remain constant throughout the range of temperatures and oxygen concentrations that the animal is likely to encounter, a necessary condition since the ventilation stream is also the principal mode of locomotion by jet propulsion. Blood oxygen-carrying capacity (from the copper concentration) was 4.6 ± 1.8vols%. Cardiac output and stroke volume were estimated from the observed VO2 values and heartbeat frequencies. Resting at 25°C, the output was close to 11.51kg−1 body mass h−1. The systemic heart of Lolliguncula weighed only 2.06 ± 0.62 g kg−1. In exercise the cardiac output must exceed 14×103 1kg−1 heart mass h−1, pumping more than the heart's own mass of blood at each stroke.

Cardio-respiratory and metabolic responses to different levels of compression during submaximal exercise

2011 ◽  
Vol 26 (3) ◽  
pp. 102-106 ◽  
Author(s):  
B Sperlich ◽  
M Haegele ◽  
M Krüger ◽  
T Schiffer ◽  
H-C Holmberg ◽  
...  
Keyword(s):  
Heart Rate ◽  
Cardiac Output ◽  
Oxygen Uptake ◽  
Stroke Volume ◽  
Oxygen Saturation ◽  
Arterial Oxygen Saturation ◽  
Peak Oxygen Uptake ◽  
Submaximal Exercise ◽  
Arterial Oxygen ◽  
Different Levels

Objective The effects of knee-high socks that applied different levels of compression (0, 10, 20, 30 and 40 mmHg) on various cardio-respiratory and metabolic parameters during submaximal running were analysed. Methods Fifteen well-trained, male endurance athletes (age: 22.2 ± 1.3 years; peak oxygen uptake: 57.2 ± 4.0 mL/minute/kg) performed a ramp test to determine peak oxygen uptake. Thereafter, all athletes carried out five periods of submaximal running (at approximately 70% of peak oxygen uptake) with and without compression socks that applied the different levels of pressure. Cardiac output and index, stroke volume, arterio-venous difference in oxygen saturation, oxygen uptake, arterial oxygen saturation, heart rate and blood lactate were monitored before and during all of these tests. Results Cardiac output ( P = 0.29) and index ( P = 0.27), stroke volume ( P = 0.50), arterio-venous difference in oxygen saturation ( P = 0.11), oxygen uptake ( P = 1.00), arterial oxygen saturation ( P = 1.00), heart rate ( P = 1.00) and arterial lactate concentration ( P = 1.00) were unaffected by compression (effect sizes = 0.00–0.65). Conclusion This first evaluation of the potential effects of increasing levels of compression on cardio-respiratory and metabolic parameters during submaximal exercise revealed no effects whatsoever.

Appropriate heart rate during exercise in Fontan patients

2020 ◽  
Vol 30 (5) ◽  
pp. 674-680
Author(s):  
Eva R. Hedlund ◽  
Liselott Söderström ◽  
Bo Lundell
Keyword(s):  
Heart Rate ◽  
Cardiac Output ◽  
Oxygen Uptake ◽  
Stroke Volume ◽  
Heart Rate Recovery ◽  
Cardiopulmonary Exercise Testing ◽  
Limiting Factor ◽  
Oxygen Pulse ◽  
Maximal Effort ◽  
Fontan Patients

AbstractObjective:To evaluate heart rate against workload and oxygen consumption during exercise in Fontan patients.Method:Fontan patients (n = 27) and healthy controls (n = 25) underwent cardiopulmonary exercise testing with linear increase of load. Heart rate and oxygen uptake were measured during tests. Heart rate recovery was recorded for 10 minutes.Results:Heart rate at midpoint (140 ± 14 versus 153 ± 11, p < 0.001) and at maximal effort (171 ± 14 versus 191 ± 10 beats per minute, p < 0.001) of test was lower for patients than controls. Heart rate recovery was similar between groups. Heart rate in relation to workload was higher for patients than controls both at midpoint and maximal effort. Heart rate in relation to oxygen uptake was similar between groups throughout test. Oxygen pulse, an indirect surrogate measure of stroke volume, was reduced at maximal effort in patients compared to controls (6.6 ± 1.1 versus 7.5 ± 1.4 ml·beat−1·m−2, p < 0.05) and increased significantly less from midpoint to maximal effort for patients than controls (p < 0.05).Conclusions:Heart rate is increased in relation to workload in Fontan patients compared with controls. At higher loads, Fontan patients seem to have reduced heart rate and smaller increase in oxygen pulse, which may be explained by inability to further increase stroke volume and cardiac output. Reduced ability to increase or maintain stroke volume at higher heart rates may be an important limiting factor for maximal cardiac output, oxygen uptake, and physical performance.

scholarly journals Cardiac output estimated noninvasively from oxygen uptake during exercise

1997 ◽  
Vol 82 (3) ◽  
pp. 908-912 ◽  
Author(s):  
William W. Stringer ◽  
James E. Hansen ◽  
K. Wasserman
Keyword(s):  
Heart Failure ◽  
Congestive Heart Failure ◽  
Cardiac Output ◽  
Linear Regression ◽  
Oxygen Uptake ◽  
Stroke Volume ◽  
Exercise Testing ◽  
Venous Blood ◽  
Cardiopulmonary Exercise Testing ◽  
Mixed Venous Blood

Stringer, William W., James E. Hansen, and K. Wasserman.Cardiac output estimated noninvasively from oxygen uptake during exercise. J. Appl. Physiol. 82(3): 908–912, 1997.—Because gas-exchange measurements during cardiopulmonary exercise testing allow noninvasive measurement of oxygen uptake (V˙o 2), which is equal to cardiac output (CO) × arteriovenous oxygen content difference [C(a-[Formula: see text])], CO and stroke volume could theoretically be estimated if the C(a-[Formula: see text]) increased in a predictable fashion as a function of %maximumV˙o 2(V˙o 2 max) during exercise. To investigate the behavior of C(a-[Formula: see text]) during progressively increasing ramp pattern cycle ergometry exercise, 5 healthy subjects performed 10 studies to exhaustion while arterial and mixed venous blood were sampled. Samples were analyzed for blood gases (pH, [Formula: see text],[Formula: see text]) and oxyhemoglobin and hemoglobin concentration with a CO-oximeter. The C(a-[Formula: see text]) (ml/100 ml) could be estimated with a linear regression [C(a-[Formula: see text]) = 5.72 + 0.105 × %V˙o 2 max; r = 0.94]. The CO estimated from the C(a-[Formula: see text]) by using the above linear regression was well correlated with the CO determined by the direct Fick method ( r = 0.96). The coefficient of variation of the estimated CO was small (7–9%) between the lactic acidosis threshold and peakV˙o 2. The behavior of C(a-[Formula: see text]), as related to peakV˙o 2, was similar regardless of cardiac function compared with similar measurements from studies in the literature performed in normal and congestive heart failure patients. In summary, CO and stroke volume can be estimated during progressive work rate exercise testing from measuredV˙o 2 (in normal subjects and patients with congestive heart failure), and the resultant linear regression equation provides a good estimate of C(a-[Formula: see text]).

scholarly journals Respiratory pump maintains cardiac stroke volume during hypovolemia in young, healthy volunteers

2018 ◽  
Vol 124 (5) ◽  
pp. 1319-1325 ◽  
Author(s):  
Maria Skytioti ◽  
Signe Søvik ◽  
Maja Elstad
Keyword(s):  
Cardiac Output ◽  
Stroke Volume ◽  
Healthy Volunteers ◽  
Negative Pressure ◽  
Spontaneous Breathing ◽  
Positive Pressure Ventilation ◽  
Control Mode ◽  
Positive Pressure ◽  
Beneficial Effects ◽  
Cardiac Stroke Volume

Spontaneous breathing has beneficial effects on the circulation, since negative intrathoracic pressure enhances venous return and increases cardiac stroke volume. We quantified the contribution of the respiratory pump to preserve stroke volume during hypovolemia in awake, young, healthy subjects. Noninvasive stroke volume, cardiac output, heart rate, and mean arterial pressure (Finometer) were recorded in 31 volunteers (19 women), 19–30 yr old, during normovolemia and hypovolemia (approximating 450- to 500-ml reduction in central blood volume) induced by lower-body negative pressure. Control-mode noninvasive positive-pressure ventilation was employed to reduce the effect of the respiratory pump. The ventilator settings were matched to each subject’s spontaneous respiratory pattern. Stroke volume estimates during positive-pressure ventilation and spontaneous breathing were compared with Wilcoxon matched-pairs signed-rank test. Values are overall medians. During normovolemia, positive-pressure ventilation did not affect stroke volume or cardiac output. Hypovolemia resulted in an 18% decrease in stroke volume and a 9% decrease in cardiac output ( P < 0.001). Employing positive-pressure ventilation during hypovolemia decreased stroke volume further by 8% ( P < 0.001). Overall, hypovolemia and positive-pressure ventilation resulted in a reduction of 26% in stroke volume ( P < 0.001) and 13% in cardiac output ( P < 0.001) compared with baseline. Compared with the situation with control-mode positive-pressure ventilation, spontaneous breathing attenuated the reduction in stroke volume induced by moderate hypovolemia by 30% (i.e., −26 vs. −18%). In the patient who is critically ill with hypovolemia or uncontrolled hemorrhage, spontaneous breathing may contribute to hemodynamic stability, whereas controlled positive-pressure ventilation may result in circulatory decompensation. NEW & NOTEWORTHY Maintaining spontaneous respiration has beneficial effects on hemodynamic compensation, which is clinically relevant for patients in intensive care. We have quantified the contribution of the respiratory pump to cardiac stroke volume and cardiac output in healthy volunteers during normovolemia and central hypovolemia. The positive hemodynamic effect of the respiratory pump was abolished by noninvasive, low-level positive-pressure ventilation. Compared with control-mode positive-pressure ventilation, spontaneous negative-pressure ventilation attenuated the fall in stroke volume by 30%.

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