Noninvasive Blood Perfusion Measurement on the Liver of an Anesthetized Rat

2007 ◽  
Author(s):  
Patricia L. Ricketts ◽  
Ashvinikumar V. Mudaliar ◽  
Brent E. Ellis ◽  
Thomas E. Diller ◽  
Elaine P. Scott ◽  
...  
Keyword(s):  
Blood Flow ◽  
Environmental Factors ◽  
Large Range ◽  
Volumetric Flow Rate ◽  
Blood Perfusion ◽  
Tissue Type ◽  
Living Tissue ◽  
Measurement Sensitivity ◽  
Perfusion Measurement ◽  
Flow Through

Blood perfusion is the local, non-directional blood flow through living tissue. It is measured as the volumetric flow rate of blood per volume of tissue and a large range of perfusion values have been reported for human tissue (i.e. 0.002–0.5 ml/ml/s). This large range is thought to be due to measurement sensitivity, environmental factors, and tissue type and location.

scholarly journals Blood Perfusion of the Kidney of Lophius Piscatorius L.

1953 ◽  
Vol 32 (2) ◽  
pp. 329-336 ◽  
Author(s):  
L. Brull ◽  
E. Nizet ◽  
E. B. Verney
Keyword(s):  
Blood Flow ◽  
Critical Level ◽  
Perfusion Pressure ◽  
Blood Perfusion ◽  
Urine Flow ◽  
The Other ◽  
Protein Nitrogen ◽  
Other Hand ◽  
Flow Through

Lophius kidneys perfused with the heparinized blood (venous) of the fish secrete urine in which total non-protein nitrogen is concentrated, magnesium highly concentrated, and chloride only slightly so or not at all. Oxygenation of the blood, or lowering the temperature of the perfusate from c. 20° to c. 5° C. does not appear to influence secretion. The blood flow through the kidneys increases with the perfusion pressure, the increase often becoming disproportionately large. The urine flow, on the other hand, above a certain critical level is largely independent of changes in perfusion pressure.

Pulsatile Blood Flow Through a Constricted Porous Artery

2020 ◽  
Vol 17 (2) ◽  
pp. 743-749
Author(s):  
Salah Uddin ◽  
Obaid Ullah Mehmood ◽  
Mahathir Mohamad ◽  
Mahmod Abd Hakim Mohmad ◽  
D. F. Jamil ◽  
...  
Keyword(s):  
Reynolds Number ◽  
Blood Flow ◽  
Flow Velocity ◽  
Nonlinear Differential Equations ◽  
Fluid Velocity ◽  
Volumetric Flow Rate ◽  
Physical Parameters ◽  
Porosity Parameter ◽  
Arterial Blood ◽  
Flow Through

In this paper a speculative study of an incompressible Newtonian blood flow through a constricted porous channel and pulsatile nature is inspected. Porosity parameter λ is incorporated in the momentum equation. Governing nonlinear differential equations are numerically evaluated by employing the perturbation method technique for a very small perturbation parameter ε 1 such that ε ≠ 0 and with conformable boundary conditions. Numerical results of the flow velocity profile and volumetric flow rate have been derived numerically and detailed graphical analysis for different physical parameters porosity, Reynolds number and stenosis has been presented. It is found that arterial blood velocity is dependent upon all of these factors and that the relationship of fluid velocity and flow is more complex and nonlinear than heretofore generally believe. Furthermore the flow velocity enhanced with Reynolds number, porosity parameter and at maximum position of the stenosis/constriction.

Thermography as a Means of Blood Perfusion Measurement

1979 ◽  
Vol 101 (4) ◽  
pp. 246-249 ◽  
Author(s):  
J. E. Francis ◽  
R. Roggli ◽  
T. J. Love ◽  
C. P. Robinson
Keyword(s):  
Blood Flow ◽  
Skin Temperature ◽  
Strain Gage ◽  
Infrared Camera ◽  
Blood Perfusion ◽  
The Body ◽  
Perfusion Rate ◽  
Perfusion Measurement ◽  
Blood Perfusion Rate ◽  
Human Forearm

The scanning infrared camera has been used to verify an analytical model relating blood perfusion rate to skin temperature. The blood perfusion rates were measured with both the mercury strain gage and the volume plethysmograph on the human forearm. Thermograms were taken of the forearm and temperature measured using an optical densitometer. Comparison of the volume plethysmograph with the strain gage, and the thermograms with the strain gage indicate thermography to be a useful means of measuring blood flow. Thermography has the advantages of being noninvasive and can be used to measure blood perfusion in parts of the body not easily monitored with occlusive techniques.

MATHEMATICAL MODELING OF BLOOD FLOW IN A POROUS VESSEL HAVING DOUBLE STENOSES IN THE PRESENCE OF AN EXTERNAL MAGNETIC FIELD

2011 ◽  
Vol 04 (02) ◽  
pp. 207-225 ◽  
Author(s):  
J. C. MISRA ◽  
A. SINHA ◽  
G. C. SHIT
Keyword(s):  
Mathematical Modeling ◽  
Magnetic Field ◽  
Mathematical Model ◽  
Blood Flow ◽  
Shear Stress ◽  
External Magnetic Field ◽  
Volumetric Flow Rate ◽  
Hematocrit Level ◽  
Flow Through ◽  
The Mathematical Model

In this paper, a mathematical model has been developed for studying blood flow through a porous vessel with a pair of stenoses under the action of an externally applied magnetic field. Blood flowing through the artery is considered to be Newtonian. This model is consistent with the principles of ferro-hydrodynamics and magnetohydrodynamics. Expressions for the velocity profile, volumetric flow rate, wall shear stress and pressure gradient have been derived analytically under the purview of the model. The above said quantities are computed for a specific set of values of the different parameters involved in the model analysis. This serves as an illustration of the validity of the mathematical model developed here. The results estimated on the basis of the computation are presented graphically. The obtained results for different values of the parameters involved in the problem under consideration, show that the flow is appreciably influenced by the presence of magnetic field and the rise in the hematocrit level.

Measurement of Regional Sodium Turnover Rates and Their Application to the Estimation of Regional Blood Flow

1957 ◽  
Vol 189 (2) ◽  
pp. 269-276 ◽  
Author(s):  
Ernest L. Dobson ◽  
George F. Warner
Keyword(s):  
Blood Flow ◽  
Turnover Rate ◽  
Regional Blood Flow ◽  
Removal Rate ◽  
Subcutaneous Administration ◽  
Blood Perfusion ◽  
Turnover Rates ◽  
Epinephrine Administration ◽  
Vascular Bed ◽  
Flow Through

It has been possible to estimate the regional blood flow through quantitative analysis of the sodium wash out curve obtained by a method which involves the injection of sodium 24 into an artery and the subsequent monitoring of the region (limb) supplied by this artery with external counters. The normal resting sodium turnover rate in the human forearm was found to be 10%/min. corresponding to a blood perfusion factor of 0.040 liters of blood per liter of tissue per minute. In addition to these quantitative values this method has given qualitative information on the pattern of the vascular bed. Analysis of the manner in which the removal rate changes with time has indicated that there are regions of widely differing vascularities in the area seen by the counter. Measurements following epinephrine administration have demonstrated not only a quantitative change in flow but a qualitative one as well. The subcutaneous administration of 1 mg epinephrine caused a doubling of the average total sodium turnover rate indicating a twofold increase in blood flow. The observed changes in the shape of the clearance curves could not be explained by a simple increase in linear flow rate and therefore must have involved some change in the character of the vascular bed, i.e. the conversion of some regions of low vascularity to regions of high vascularity.

scholarly journals Blood perfusion of the kidney of Lophius piscatorius L.: II. Influence of perfusion pressure on urine volume

1954 ◽  
Vol 33 (3) ◽  
pp. 733-738 ◽  
Author(s):  
L. Brull ◽  
Y. Cuypers
Keyword(s):  
Blood Flow ◽  
Oxygen Consumption ◽  
Critical Level ◽  
Perfusion Pressure ◽  
Urine Volume ◽  
Blood Perfusion ◽  
Urine Flow ◽  
Active Process ◽  
Flow Through ◽  
Water Secretion

SummaryThe urine secretion of the kidneys of Lophius piscatorius perfused with heparinized Lophius blood is very sensitive to perfusion pressure below a critical level, above which it becomes insensitive. The response of the urine flow to pressure takes the form of an exponential curve.The blood flow through the kidneys, while rising slowly at pressures of about 20–30 mm of water, responds arithmetically to pressure above such levels.At present it is impossible to make out whether pressure or blood flow has the greatest influence on secretion.Water secretion in the aglomerular kidney is an active process. The oxygen consumption of the Lophius kidney is unmeasurably low, yet remains a possible factor in secretion.

scholarly journals A Physiologic Model for the Problem of Blood Flow through Diseased Blood Vessels

2016 ◽  
Vol 5 (2) ◽  
pp. 58
Author(s):  
Sapna Ratan Shah ◽  
S. U. Siddiqui
Keyword(s):  
Blood Flow ◽  
Shear Stress ◽  
Wall Shear Stress ◽  
Shape Parameter ◽  
Fluid Model ◽  
Porous Wall ◽  
Volumetric Flow Rate ◽  
Wall Model ◽  
Flow Through ◽  
Wall Shear

This study focuses on the behavior of blood flow through diseased artery in the presence of porous effects. The laminar, incompressible, fully developed, non-Newtonian in an artery having axially non-symmetric but radially symmetric stenosis is numerically studied. Here blood is represented as Herschel-Bulkley fluid model and flow model is shown by the Navier-Stokes and the continuity equations. Using appropriate boundary conditions, numerical expression for volumetric flow rate, pressure drop and wall shear stress have been derived. The expressions are computed numerically and results are presented graphically. The effects of porous parameter on wall shear stress, stenosis length, stenosis size and stenosis shape parameter are discussed. The wall shear stress increases as the porous parameter, stenosis size and stenosis length increases, but as the stenosis shape parameter increases, the wall shear stress decreases. The work shows that the results obtained from the porous wall model are significantly different from those obtained by the rigid wall model.

scholarly journals The Effect of Slip Velocity on Unsteady Peristalsis MHD Blood Flow through a Constricted Artery Experiencing Body Acceleration

2019 ◽  
Vol 24 (3) ◽  
pp. 645-659 ◽  
Author(s):  
J. Nandal ◽  
S. Kumari ◽  
R. Rathee
Keyword(s):  
Blood Flow ◽  
Shear Stress ◽  
Wall Shear Stress ◽  
Flow Rate ◽  
Axial Velocity ◽  
Slip Velocity ◽  
Volumetric Flow Rate ◽  
Body Acceleration ◽  
Stenosed Artery ◽  
Flow Through

Abstract In this analysis, we present a theoretical study to examine the combined effect of both slip velocity and periodic body acceleration on an unsteady generalized non-Newtonian blood flow through a stenosed artery with permeable wall. A constant transverse magnetic field is applied on the peristaltic flow of blood, treating it as an elastico-viscous, electrically conducting and incompressible fluid. Appropriate transformation methods are adopted to solve the unsteady non-Newtonian axially symmetric momentum equation in the cylindrical polar coordinate system with suitably prescribed conditions. To validate the applicability of the proposed analysis, analytical expressions for the axial velocity, fluid acceleration, wall shear stress and volumetric flow rate are computed and for having an adequate insight to blood flow behavior through a stenosed artery, graphs have been plotted with varying values of flow variables, to analyse the influence of the axial velocity, wall shear stress and volumetric flow rate of streaming blood.

INFLUENCE OF SLIP VELOCITY ON BLOOD FLOW THROUGH AN ARTERY WITH PERMEABLE WALL: A THEORETICAL STUDY

2012 ◽  
Vol 05 (05) ◽  
pp. 1250042 ◽  
Author(s):  
A. SINHA ◽  
J. C. MISRA
Keyword(s):  
Reynolds Number ◽  
Blood Flow ◽  
Shear Stress ◽  
Slip Velocity ◽  
Flow Resistance ◽  
Theoretical Study ◽  
Perturbation Technique ◽  
Volumetric Flow Rate ◽  
Arterial Segment ◽  
Flow Through

A theoretical investigation concerning the influence of slip velocity on the flow of blood through an artery having its wall permeable has been carried out. Here blood is treated as a homogeneous Newtonian fluid. The flow is characterized by three parameters: β the ratio of radius to length of the arterial segment, Re the characteristic Reynolds number associated with the pressure outside the arterial segment and ϵ the filtration coefficient. The problem has been solved by the use of a perturbation technique. ϵ is considered to be very small, ensuring the validity of the perturbation method. The computed numerical results are presented graphically to depict the variations in velocity, volumetric flow rate, wall shear stress and flow resistance.

ROLE OF SLIP VELOCITY IN BLOOD FLOW THROUGH STENOSED ARTERIES: A NON-NEWTONIAN MODEL

2007 ◽  
Vol 07 (03) ◽  
pp. 337-353 ◽  
Author(s):  
J. C. MISRA ◽  
G. C. SHIT
Keyword(s):  
Blood Flow ◽  
Skin Friction ◽  
Flow Rate ◽  
Slip Velocity ◽  
Flow Resistance ◽  
Volumetric Flow Rate ◽  
Flow Through ◽  
Analytical Expressions ◽  
Insight Into

A mathematical model is developed in this paper for studying blood flow through a stenosed arterial segment by taking into account the slip velocity at the wall of the artery. Consideration of the non-Newtonian character of blood is made, where a constitutive relation of blood is described by the Herschel–Bulkley equation. The effect of slip at the arterial wall in the presence of mild, moderate, and severe stenosis growth at the lumen of an artery is investigated. Analytical expressions for skin friction, flow resistance, and the flow rate are derived by using the model. The derived expressions are computed numerically by considering an illustrative example. The study provides an insight into the effects of slip velocity on the volumetric flow rate of blood, flow resistance, and skin friction.

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