scholarly journals The dual roles of red blood cells in tissue oxygen delivery: oxygen carriers and regulators of local blood flow

2009 ◽  
Vol 212 (21) ◽  
pp. 3387-3393 ◽  
Author(s):  
F. B. Jensen
Keyword(s):  
Blood Flow ◽  
Red Blood Cells ◽  
Oxygen Delivery ◽  
Blood Cells ◽  
Oxygen Carriers ◽  
Tissue Oxygen ◽  
Local Blood Flow ◽  
Dual Roles ◽  
Tissue Oxygen Delivery

Hemodynamic changes induced by low blood oxygen affinity in dogs

1993 ◽  
Vol 264 (2) ◽  
pp. R396-R401 ◽  
Author(s):  
J. F. Liard ◽  
M. P. Kunert
Keyword(s):  
Cardiac Output ◽  
Red Blood Cells ◽  
Oxygen Delivery ◽  
Total Peripheral Resistance ◽  
Blood Cells ◽  
Exchange Transfusion ◽  
Peripheral Resistance ◽  
Control Group ◽  
Tissue Oxygen ◽  
Tissue Oxygen Delivery

Increased tissue oxygen delivery may play a role in the increased vascular resistance that develops in volume-expanded hypertension. This hypothesis was tested by decreasing the affinity of hemoglobin for oxygen in dogs to increase unloading of oxygen to the tissues. Six chronically instrumented dogs were studied before and for 7 days after partial exchange transfusion with red blood cells modified by incorporation of inositol hexaphosphate, which, 1 h after exchange, increased the PO2 value at which hemoglobin is half-saturated with oxygen (P50) to 38.8 +/- 2.1 mmHg from a control value of 31 +/- 1.5 mmHg. Cardiac output (electromagnetic flowmeter) fell to 92.5 +/- 7.4 ml.kg-1.min-1 after 2-4 h from control values between 120.2 +/- 5.7 and 125.8 +/- 4.6 ml.kg-1.min-1. One day later, cardiac output was still significantly decreased to 104.0 +/- 5.9 ml.kg-1.min-1. As P50 returned to control over the next few days, so did cardiac output. Two to four hours after exchange, total peripheral resistance was increased to 1,144 +/- 73 mmHg.l-1.kg.min from control values between 762 +/- 26 and 790 +/- 32 mmHg.l-1.kg.min. It was still increased to 993 +/- 51 mmHg.l-1.kg.min after 1 day. Oxygen consumption did not change significantly. Cardiac output and peripheral resistance changes were significantly different from those measured in a control group of six dogs receiving exchange transfusion with sham-shifted red blood cells without significant P50 changes. These results suggest that an increase in tissue oxygen delivery can raise total peripheral resistance in dogs in the absence of primary changes in fluid volumes, blood flow, or blood pressure.

scholarly journals Oxygen Transport during Ex Situ Machine Perfusion of Donor Livers Using Red Blood Cells or Artificial Oxygen Carriers

2020 ◽  
Vol 22 (1) ◽  
pp. 235
Author(s):  
Silke B. Bodewes ◽  
Otto B. van Leeuwen ◽  
Adam M. Thorne ◽  
Bianca Lascaris ◽  
Rinse Ubbink ◽  
...  
Keyword(s):  
Red Blood Cells ◽  
Oxygen Transport ◽  
Oxygen Delivery ◽  
Blood Cells ◽  
Marine Invertebrate ◽  
Oxygen Carrier ◽  
Ex Situ ◽  
Machine Perfusion ◽  
Oxygen Carriers ◽  
Advantages And Disadvantages

Oxygenated ex situ machine perfusion of donor livers is an alternative for static cold preservation that can be performed at temperatures from 0 °C to 37 °C. Organ metabolism depends on oxygen to produce adenosine triphosphate and temperatures below 37 °C reduce the metabolic rate and oxygen requirements. The transport and delivery of oxygen in machine perfusion are key determinants in preserving organ viability and cellular function. Oxygen delivery is more challenging than carbon dioxide removal, and oxygenation of the perfusion fluid is temperature dependent. The maximal oxygen content of water-based solutions is inversely related to the temperature, while cellular oxygen demand correlates positively with temperature. Machine perfusion above 20 °C will therefore require an oxygen carrier to enable sufficient oxygen delivery to the liver. Human red blood cells are the most physiological oxygen carriers. Alternative artificial oxygen transporters are hemoglobin-based oxygen carriers, perfluorocarbons, and an extracellular oxygen carrier derived from a marine invertebrate. We describe the principles of oxygen transport, delivery, and consumption in machine perfusion for donor livers using different oxygen carrier-based perfusion solutions and we discuss the properties, advantages, and disadvantages of these carriers and their use.

scholarly journals Mathematical Models for Some Aspects of Blood Microcirculation

Symmetry ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 1020
Author(s):  
Angiolo Farina ◽  
Antonio Fasano ◽  
Fabio Rosso
Keyword(s):  
Blood Flow ◽  
Mathematical Models ◽  
Red Blood Cells ◽  
Blood Cells ◽  
Blood Rheology ◽  
Small Class ◽  
Small Vessels ◽  
Blood Microcirculation ◽  
Peculiar Behavior

Blood rheology is a challenging subject owing to the fact that blood is a mixture of a fluid (plasma) and of cells, among which red blood cells make about 50% of the total volume. It is precisely this circumstance that originates the peculiar behavior of blood flow in small vessels (i.e., roughly speaking, vessel with a diameter less than half a millimeter). In this class we find arteriolas, venules, and capillaries. The phenomena taking place in microcirculation are very important in supporting life. Everybody knows the importance of blood filtration in kidneys, but other phenomena, of not less importance, are known only to a small class of physicians. Overviewing such subjects reveals the fascinating complexity of microcirculation.

Local blood flow, oxygen tension, and oxygen consumption in the rat spinal cord

1983 ◽  
Vol 58 (4) ◽  
pp. 526-530 ◽  
Author(s):  
Nariyuki Hayashi ◽  
Barth A. Green ◽  
Mayra Gonzalez-Carvajal ◽  
Joseph Mora ◽  
Richard P. Veraa
Keyword(s):  
Spinal Cord ◽  
Blood Flow ◽  
Oxygen Consumption ◽  
Oxygen Tension ◽  
Tissue Oxygen ◽  
Local Blood Flow ◽  
Rat Spinal Cord ◽  
Spinal Cord Blood Flow ◽  
Content Type ◽  
Tissue Oxygen Consumption

✓ Using a reliable and reproducible microelectrode technique, consistent simultaneous measurements of local spinal cord blood flow (SCBF), tissue oxygen tension, and tissue oxygen consumption were made at cervical, thoracic, and lumbar levels in the rat spinal cord. These observations showed that the metabolic state is maintained constant along the cord, despite significant variations in vasculature. The physiological and anatomical aspects of these findings are discussed.

Multiscale Modeling of Flow Induced Thrombogenicity Using Dissipative Particle Dynamics and Molecular Dynamics

2013 ◽  
Author(s):  
Danny Bluestein ◽  
João S. Soares ◽  
Peng Zhang ◽  
Chao Gao ◽  
Seetha Pothapragada ◽  
...  
Keyword(s):  
Molecular Dynamics ◽  
Blood Flow ◽  
Red Blood Cells ◽  
Platelet Activation ◽  
Blood Cells ◽  
Dissipative Particle Dynamics ◽  
Particle Dynamics ◽  
Coagulation Cascade ◽  
Shear Stresses ◽  
Activated Platelets

The coagulation cascade of blood may be initiated by flow induced platelet activation, which prompts clot formation in prosthetic cardiovascular devices and arterial disease processes. While platelet activation may be induced by biochemical agonists, shear stresses arising from pathological flow patterns enhance the propensity of platelets to activate and initiate the intrinsic pathway of coagulation, leading to thrombosis. Upon activation platelets undergo complex biochemical and morphological changes: organelles are centralized, membrane glycoproteins undergo conformational changes, and adhesive pseudopods are extended. Activated platelets polymerize fibrinogen into a fibrin network that enmeshes red blood cells. Activated platelets also cross-talk and aggregate to form thrombi. Current numerical simulations to model this complex process mostly treat blood as a continuum and solve the Navier-Stokes equations governing blood flow, coupled with diffusion-convection-reaction equations. It requires various complex constitutive relations or simplifying assumptions, and is limited to μm level scales. However, molecular mechanisms governing platelet shape change upon activation and their effect on rheological properties can be in the nm level scales. To address this challenge, a multiscale approach which departs from continuum approaches, may offer an effective means to bridge the gap between macroscopic flow and cellular scales. Molecular dynamics (MD) and dissipative particle dynamics (DPD) methods have been employed in recent years to simulate complex processes at the molecular scales, and various viscous fluids at low-to-high Reynolds numbers at mesoscopic scales. Such particle methods possess important properties at the mesoscopic scale: complex fluids with heterogeneous particles can be modeled, allowing the simulation of processes which are otherwise very difficult to solve by continuum approaches. It is becoming a powerful tool for simulating complex blood flow, red blood cells interactions, and platelet-mediated thrombosis involving platelet activation, aggregation, and adhesion.

Pulse oximetry

2007 ◽  
pp. 327-330
Keyword(s):  
Oxygen Saturation ◽  
Pulse Oximetry ◽  
Optical Density ◽  
Oxygen Delivery ◽  
Tissue Oxygen ◽  
Non Invasive ◽  
Tissue Oxygen Delivery ◽  
Invasive Method ◽  
Beer’S Law ◽  
Light Absorbance

Pulse oximetry 328 When employed correctly, pulse oximetry is a rapid non-invasive method of assessing one of the key components of tissue oxygen delivery: the oxygen saturation of haemoglobin (SaO2). • Based on the laws of light absorbance and optical density (Lambert's law and Beer's law), i.e. the principle that deoxygenated and oxygenated hemoglobin absorb light at different wavelengths....

Acute isovolemic anemia in anesthetized chickens

1976 ◽  
Vol 231 (5) ◽  
pp. 1451-1456 ◽  
Author(s):  
TE Nightingale
Keyword(s):  
Cardiac Output ◽  
Oxygen Delivery ◽  
Peripheral Resistance ◽  
Right Atrial ◽  
Tissue Oxygen ◽  
Cardiovascular Failure ◽  
Oxygen Transport Capacity ◽  
Dextran 70 ◽  
Tissue Oxygen Delivery ◽  
Viscosity Changes

Acute isovolemic anemia was produced in anesthetized chickens by serial exchanges of 6% dextran 70 equal to 1% of body weight to quantitate cardiovascular and metabolic parameters. When hematocrit (Hct) and hemoglobin (Hb) levels were reduced by 50% (from 33.3 to 16.3 vol %, and from 10.3 to 5.4 g/100 g, respectively, P less than 0.001), tissue oxygen delivery was maintained by increases in cardiac output (CO), stroke volume (SV), oxygen extraction, and reduced total peripheral resistance (TPR). Heart rate, right atrial pressure, and oxygen consumption (Vo2) were unchanged. Further reductions in Hct and Hb (to 10.8 vol % and 3.7 g/100 g, respectively), were accompanied by cardiovascular failure, as evidenced by falling CO, SV, tissue oxygen delivery, and Vo2. Relative apparent viscosity determinations on the exchanged blood-dextran mixtures indicated that large viscosity changes occurred with the first exchange whereas subsequent exchanges had small incremental viscosity changes. These data indicate that in acutely anemic chickens, oxygen transport capacity was maintained by increased cardiac output and decreased peripheral resistance, unless the severity of the anemia resulted in cardiovascular failure.

scholarly journals Cremaster muscle perfusion, oxygenation, and heterogeneity revealed by a new automated acquisition system in a rodent model of prolonged hemorrhagic shock

2019 ◽  
Vol 127 (6) ◽  
pp. 1548-1561
Author(s):  
Ivo P. Torres Filho ◽  
David Barraza ◽  
Kim Hildreth ◽  
Charnae Williams ◽  
Michael A. Dubick
Keyword(s):  
Hemorrhagic Shock ◽  
Oxygen Delivery ◽  
Repeated Measurements ◽  
Laser Speckle ◽  
Automated System ◽  
Cremaster Muscle ◽  
Tissue Oxygen ◽  
Hypoxia Ischemia ◽  
Tissue Oxygen Delivery ◽  
Muscle Homeostasis

Local blood flow/oxygen partial pressure (Po2) distributions and flow-Po2 relationships are physiologically relevant. They affect the pathophysiology and treatment of conditions like hemorrhagic shock (HS), but direct noninvasive measures of flow, Po2, and their heterogeneity during prolonged HS are infrequently presented. To fill this void, we report the first quantitative evaluation of flow-Po2 relationships and heterogeneities in normovolemia and during several hours of HS using noninvasive, unbiased, automated acquisition. Anesthetized rats were subjected to tracheostomy, arterial/venous catheterizations, cremaster muscle exteriorization, hemorrhage (40% total blood volume), and laparotomy. Control animals equally instrumented were not subjected to hemorrhage/laparotomy. Every 0.5 h for 4.5 h, noninvasive laser speckle contrast imaging and phosphorescence quenching were employed for nearly 7,000 flow/Po2 measurements in muscles from eight animals, using an automated system. Precise alignment of 16 muscle areas allowed overlapping between flow and oxygenation measurements to evaluate spatial heterogeneity, and repeated measurements were used to estimate temporal heterogeneity. Systemic physiological parameters and blood chemistry were simultaneously assessed by blood samplings replaced with crystalloids. Hemodilution was associated with local hypoxia, but increased flow prevented major oxygen delivery decline. Adding laparotomy and prolonged HS resulted in hypoxia, ischemia, decreased tissue oxygen delivery, and logarithmic flow/Po2 relationships in most regions. Flow and Po2 spatial heterogeneities were higher than their respective temporal heterogeneities, although this did not change significantly over the studied period. This quantitative framework establishes a basis for evaluating therapies aimed at restoring muscle homeostasis, positively impacting outcomes of civilian and military trauma/HS victims. NEW & NOTEWORTHY This is the first study on flow-Po2 relationships during normovolemia, hemodilution, and prolonged hemorrhagic shock using noninvasive methods in multiple skeletal muscle areas of monitored animals. Automated flow/Po2 measurements revealed temporal/spatial heterogeneities, hypoxia, ischemia, and decreased tissue oxygen delivery after trauma/severe hemorrhage. Hemodilution was associated with local hypoxia, but hyperemia prevented a major decline in oxygen delivery. This framework provides a quantitative basis for testing therapeutics that positively impacts muscle homeostasis and outcomes of trauma/hemorrhagic shock victims.

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