Variations in cardiac output associated with hemoglobin levels in anesthetized sheep

1965 ◽  
Vol 20 (1) ◽  
pp. 16-18 ◽  
Author(s):  
D. F. J. Halmagyi ◽  
B. Starzecki ◽  
G. J. Horner
Keyword(s):  
Cardiac Output ◽  
Carrying Capacity ◽  
Blood Viscosity ◽  
Cell Concentration ◽  
Wide Spectrum ◽  
Laboratory Animals ◽  
Normal Range ◽  
Pulmonary Arterial ◽  
Oxygen Carrying Capacity ◽  
Normal Laboratory

Hemoglobin levels in sheep was found to be related inversely to the logarithm of cardiac index and directly to the calculated systemic and pulmonary arterial resistances over a wide spectrum of hemoglobin concentrations including the normal range. It appeared to be based on changes in blood viscosity produced by a varying red cell concentration. The continuous adjustment of hemoglobin levels and cardiac output may account for the variability of cardiac output values in normal laboratory animals and may represent a mechanism maintaining oxygen delivery to the tissues in the presence of changing oxygen carrying capacity. blood viscosity; vascular resistance; oxygen carrying capacity Submitted on May 15, 1964

The Influence of Nutritional State on the Circulatory and Respiratory Physiology of the Shore Crab, Carcinus Maenas

1985 ◽  
Vol 65 (1) ◽  
pp. 69-78 ◽  
Author(s):  
M. H. Depledge
Keyword(s):  
Cardiac Output ◽  
Oxygen Consumption ◽  
Salinity Stress ◽  
Carrying Capacity ◽  
Carcinus Maenas ◽  
Nutritional State ◽  
Respiratory Physiology ◽  
Shore Crab ◽  
Decapod Crustaceans ◽  
Oxygen Carrying Capacity

The oxygen-carrying capacity of the blood of decapod crustaceans fluctuates widely. Salinity stress results in doubling of haemocyanin concentration within 24–48 h in Carcinus maenas (Boone & Schoeffeniels, 1979) while in the lobster, Homarus gammarus respiratory pigment levels are very low prior to and following moulting (Spoek, 1974). In general, however, the most important factor regulating haemocyanin concentration is nutritional state. Following starvation low values are recorded (Wieser, 1965; Uglow, 1969; Djangmah, 1970) and there are concomitant reductions in ventilation, oxygen consumption and cardiac output (Ansell, 1973; Marsden, Newell & Ahsanullah, 1973; Wallace, 1973). The interrelationships between these events are poorly understood.

scholarly journals Reduction of Oxygen-Carrying Capacity Weakens the Effects of Increased Plasma Viscosity on Cardiac Performance in Anesthetized Hemodilution Model

2012 ◽  
Vol 2012 ◽  
pp. 1-9
Author(s):  
Surapong Chatpun ◽  
Pedro Cabrales
Keyword(s):  
Cardiac Output ◽  
Carrying Capacity ◽  
Oxygen Delivery ◽  
Maximum Rate ◽  
Systolic Pressure ◽  
Pressure Change ◽  
Plasma Viscosity ◽  
Cardiac Performance ◽  
Dextran 70 ◽  
Oxygen Carrying Capacity

We investigated the effects of reduced oxygen-carrying capacity on cardiac function during acute hemodilution, while the plasma viscosity was increased in anesthetized animals. Two levels of oxygen-carrying capacity were created by 1-step and 2-step hemodilution in male golden Syrian hamsters. In the 1-step hemodilution (1-HD), 40% of the animals' blood volume (BV) was exchanged with 6% dextran 70 kDa (Dx70) or dextran 2000 kDa (Dx2M). In the 2-step hemodilution (2-HD), 25% of the animals' BV was exchanged with Dx70 followed by 40% BV exchanged with Dx70 or Dx2M after 30 minutes of first hemodilution. Oxygen delivery in the 2-HD group consequently decreased by 17% and 38% compared to that in the 1-HD group hemodiluted with Dx70 and Dx2M, respectively. End-systolic pressure and maximum rate of pressure change in the 2-HD group significantly lowered compared with that in the 1-HD group for both Dx70 and Dx2M. Cardiac output in the 2-HD group hemodiluted with Dx2M was significantly higher compared with that hemodiluted with Dx70. In conclusion, increasing plasma viscosity associated with lowering oxygen-carrying capacity should be considerably balanced to maintain the cardiac performance, especially in the state of anesthesia.

Integrated Evaluation of Neonatal Hemodynamics, Part 2: Systematic Bedside Assessment

2016 ◽  
Vol 35 (4) ◽  
pp. 192-203 ◽  
Author(s):  
Yasser N. Elsayed ◽  
Debbie Fraser
Keyword(s):  
Blood Pressure ◽  
Cardiac Output ◽  
Oxygen Uptake ◽  
Carrying Capacity ◽  
Clinical Markers ◽  
Organ Function ◽  
Term Infants ◽  
Routine Monitoring ◽  
Oxygen Carrying Capacity ◽  
Sufficient Oxygen

AbstractIntact hemodynamics results when there is adequate oxygen uptake by the respiratory system, normal cardiac output, sufficient oxygen-carrying capacity of blood, and intact autoregulatory mechanisms to maintain enough oxygenation for normal end-organ function. The current routine monitoring of cardiovascular dynamics in sick preterm and term infants has been based on incomplete evaluation and relies on nonspecific and sometimes misleading clinical markers such as blood pressure. A thorough understanding of perinatal and neonatal cardiovascular, respiratory, oxygen, and other specific end-organ physiology is also mandatory for proper targeted interpretation.

Effects of Venesection on Leg Blood Flow in Claudicants with High-Normal Haematocrit

1988 ◽  
Vol 33 (4) ◽  
pp. 298-299 ◽  
Author(s):  
A.R. Turner ◽  
G.D.O. Lowe ◽  
C.D. Forbes ◽  
J. G. Pollock
Keyword(s):  
Blood Flow ◽  
Intermittent Claudication ◽  
Carrying Capacity ◽  
Blood Viscosity ◽  
Oxygen Delivery ◽  
Peak Flow ◽  
Haemoglobin Concentration ◽  
Leg Blood Flow ◽  
Calf Blood Flow ◽  
Oxygen Carrying Capacity

Patients with intermittent claudication frequently have high-normal levels of haematocrit and hence blood viscosity, which may contribute to decreased calf blood flow on exercise, and hence to the symptom of claudication. Reduction in haematocrit and viscosity by serial venesection in eight patients with stable claudication and high-normal haematocrit (mean 0.50) was performed, and the effects on claudication, calf blood flow, and calf oxygen delivery were studied. Following reduction in haematocrit to low-normal levels (mean 0.44), resting calf blood flow was unchanged; peak flow after ischaemic exercise increased slightly (+17%), but peak oxygen delivery (peak flow × haemoglobin concentration) was unchanged. Hence any increase in calf blood flow in the symptomatic leg is balanced by a decrease in oxygen-carrying capacity after venesection. No increase in claudication time would therefore be expected, and none was observed in the present study.

Consultation with the Specialist

1992 ◽  
Vol 13 (10) ◽  
pp. 379-380
Author(s):  
William B. Strong
Keyword(s):  
Cardiac Output ◽  
Oxygen Saturation ◽  
Carrying Capacity ◽  
Hemoglobin Concentration ◽  
Cyanotic Congenital Heart Disease ◽  
Compensatory Mechanism ◽  
Peripheral Tissues ◽  
Arterial Blood ◽  
Infant And Young Child ◽  
Oxygen Carrying Capacity

What is the likely pathophysiology of this event? What are the more common complications of hypoxemia in the older infant and young child? This clinical scenario is uncommon, but it represents one of the two feared central nervous system complications of cyanotic congenital heart disease, (ie, cerebrovascular accident and brain abscess). A uniform response to hypoxemia of cardiac etiology is the production of erythropoietin to produce more red blood cells. This is a compensatory mechanism to maintain oxygen delivery to the peripheral tissues. Normally, hemoglobin is about 96% saturated with oxygen. Therefore, the oxygen-carrying capacity of blood with a normal hemoglobin concentration of 15 g/dL is approximately 20.3 mL of oxygen per 100 mL of blood (ie, 15 g of hemoglobin x 1.35 mL of O2 per g of hemoglobin = 20.3). The oxygen content of blood equals the oxygen-carrying capacity multiplied by the oxygen saturation. At a normal oxygen saturation of 96%, the O2 content of arterial blood (Hgb 15 g/dL) equals 19.5 mL/dL (96% x 20.3 mm3/dL) or 195 mL per liter of cardiac output. The arterial O2 content of this child, assuming an average arterial saturation of 85%, will be 11.1 mL/dL. Therefore, every liter (10 dL) of cardiac output will carry 111 mL of O2 or 84 mL of O2 less than the child with a 15 g/dL hemoglobin level.

Haemorheology of the eastern grey kangaroo and the Tasmanian devil

2011 ◽  
Vol 59 (1) ◽  
pp. 26 ◽  
Author(s):  
Michael J. Simmonds ◽  
Oguz K. Baskurt ◽  
Herbert J. Meiselman ◽  
Michael Pyne ◽  
Michael Kakanis ◽  
...  
Keyword(s):  
Surface Charge ◽  
Carrying Capacity ◽  
Blood Viscosity ◽  
Haemoglobin Concentration ◽  
Scanning Electron Micrographs ◽  
Tasmanian Devil ◽  
Grey Kangaroo ◽  
Rbc Aggregation ◽  
Oxygen Carrying Capacity ◽  
Rbc Deformability

The blood of two Australian marsupials, the eastern grey kangaroo (Macropus giganteus) and the Tasmanian devil (Sarcophilus harrisii), has been reported to have greater oxygen-carrying capacity (i.e. haemoglobin content) when compared with that of placental mammals. We investigated whether alterations of blood rheological properties are associated with the increased oxygen-carrying capacity of these marsupials. Eastern grey kangaroos (n = 6) and Tasmanian devils (n = 4) were anaesthetised for blood sampling; human blood (n = 6) was also sampled for comparison. Laboratory measurements included blood and plasma viscosity, red blood cell (RBC) deformability, RBC aggregation and the intrinsic tendency of RBC to aggregate, RBC surface charge and haematological parameters. Scanning electron micrographs of RBC from each species provided morphological information. High-shear blood viscosity at native haematocrit was highest for the Tasmanian devil. When haematocrit was adjusted to 0.4 L L–1, lower-shear blood viscosity was highest for the eastern grey kangaroo. RBC deformability was greatly reduced for the Tasmanian devil. Eastern grey kangaroo blood had the highest RBC aggregation, whereas Tasmanian devil RBC did not aggregate. The surface charge of RBC for marsupials was ~15% lower than that of humans. The dependence of oxygen-delivery effectiveness on haemoglobin concentration (i.e. oxygen content) and blood viscosity was quantitated by calculating the haematocrit to blood viscosity ratio and was 15–25% lower for marsupials compared with humans. Our results suggest that environmental pressures since the marsupial–monotreme divergence have influenced the development of vastly different strategies to maintain a match between oxygen demand and delivery.

Effects of acute prolonged hypoxia on cardiovascular dynamics in dogs

1977 ◽  
Vol 43 (5) ◽  
pp. 784-789 ◽  
Author(s):  
J. F. Borgia ◽  
S. M. Horvath
Keyword(s):  
Blood Flow ◽  
Cardiac Output ◽  
Cardiac Index ◽  
Carrying Capacity ◽  
Hemoglobin Concentration ◽  
Severe Hypoxia ◽  
Systemic Hypertension ◽  
Anesthetized Dogs ◽  
Oxygen Tensions ◽  
Oxygen Carrying Capacity

Intact anesthetized dogs were exposed for 75 min to either 5.75, 9.0, or 12.0% oxygen in nitrogen. Although pulmonary artery pressures were significantly elevated in all hypoxic exposures, systemic hypertension occurred only at the onset of severe hypoxia(5.75% O2). Coronary blood flow increased from an average of 130 during normoxia to a peak of 400 ml/100 g per min during inhalation of 5.75% O2, and coronary sinus oxygen tensions of 8 Torr and oxygen contents of 1.1 ml/100 ml were sustained for 75 min without biochemical, functional, or electrophysiological evidence of myocardial ischemia. Cardiac index (CI) increased significantly only during severe hypoxia (5.75% O2) with the greatest elevation after 30 min. Subsequently, CI decreased concomitantly with a 27% elevation in arterial hemoglobin concentration and oxygen-carrying capacity. It is concluded that the hypoxic threshold for significant elevations of cardiac output is between 6.0 and 9.0% O2.

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