A Theory of Blood Flow in Skeletal Muscle

1988 ◽  
Vol 110 (1) ◽  
pp. 20-26 ◽  
Author(s):  
G. W. Schmid-Scho¨nbein
Keyword(s):  
Skeletal Muscle ◽  
Blood Flow ◽  
Flow Curve ◽  
Oscillatory Flow ◽  
Viscoelastic Model ◽  
Low Flow ◽  
Pressure Flow ◽  
Closed Form Solutions ◽  
Wide Range ◽  
Theoretical Results

A theoretical analysis of blood flow in the microcirculation of skeletal muscle is provided. The flow in the microvessels of this organ is quasi steady and has a very low Reynolds number. The blood is non-Newtonian and the blood vessels are distensible with viscoelastic properties. A formulation of the problem is provided using a viscoelastic model for the vessel wall which was recently derived from measurements in the rat spinotrapezius muscle (Skalak and Schmid-Scho¨nbein, 1986b). Closed form solutions are derived for several physiologically important cases, such as perfusion at steady state, transient and oscillatory flows. The results show that resting skeletal muscle has, over a wide range of perfusion pressures an almost linear pressure-flow curve. At low flow it exhibits nonlinearities. Vessel distensibility and the non-Newtonian properties of blood both have a strong influence on the shape of the pressure-flow curve. During oscillatory flow the muscle exhibits hysteresis. The theoretical results are in qualitative agreement with experimental observations.

Decreased skeletal muscle pump activity in patients with postural tachycardia syndrome and low peripheral blood flow

2004 ◽  
Vol 286 (3) ◽  
pp. H1216-H1222 ◽  
Author(s):  
Julian M. Stewart ◽  
Marvin S. Medow ◽  
Leslie D. Montgomery ◽  
Kenneth McLeod
Keyword(s):  
Skeletal Muscle ◽  
Blood Flow ◽  
Blood Volume ◽  
Orthostatic Intolerance ◽  
Low Flow ◽  
Peripheral Blood Flow ◽  
Muscle Pump ◽  
Postural Tachycardia ◽  
Calf Blood Flow ◽  
Skeletal Muscle Pump

Standing translocates thoracic blood volume into the dependent body. The skeletal muscle pump participates in preventing orthostatic intolerance by enhancing venous return. We investigated the hypothesis that skeletal muscle pump function is impaired in postural tachycardia (POTS) associated with low calf blood flow (low-flow POTS) and depends in general on muscle blood flow. We compared 12 subjects that have low-flow POTS with 10 controls and 7 patients that have POTS and normal calf blood flow using strain-gauge plethysmography to measure peripheral blood flow, venous capacitance, and calf muscle pump function. Blood volume was estimated by dye dilution. We found that calf circumference was reduced in low-flow POTS (32 ± 1 vs. 39 ± 3 and 43 ± 3 cm) and, compared with controls and POTS patients with normal blood flow, is related to the reduced fraction of calf venous capacity emptied during voluntary muscle contraction (ejection fraction, 0.52 ± 0.07 vs. 0.76 ± 0.07 and 0.80 ± 0.06). We found that blood flow was linearly correlated ( rp = 0.69) with calf circumference (used as a surrogate for muscle mass). Blood volume measurements were 2.2 ± 0.3 in low-flow POTS vs. 2.6 ± 0.5 in controls ( P = 0.17) and 2.4 ± 0.7 in normal-flow POTS patients. Decreased calf blood flow may reduce calf size in POTS and thereby impair the upright ejective ability of the skeletal muscle pump and further contribute to overall reduced blood flow and orthostatic intolerance in these patients.

Distensibility and pressure-flow relationship of the pulmonary circulation. I. Single-vessel model

1990 ◽  
Vol 68 (4) ◽  
pp. 1501-1513 ◽  
Author(s):  
Z. Bshouty ◽  
M. Younes
Keyword(s):  
Pulmonary Circulation ◽  
Low Flow ◽  
Elastic Behavior ◽  
Vasomotor Tone ◽  
Pressure Flow ◽  
Parallel Shift ◽  
Lack Of Information ◽  
Wide Range ◽  
Relationship Of ◽  
The Relationship

To ascertain the relative contributions of vascular distensibility and nonhomogeneous behavior within the pulmonary circulation to the distinctive nonlinear relationship between inflow pressure (Pin) and flow [pressure-flow (P-F) relationship] and between Pin and outflow pressure (Pout) at constant flow (Pin-Pout relationship), we developed a multibranched model in which the elastic behavior of, and forces acting on, individual branches can be varied independently. The response of the multibranched model is described in the companion article (J. Appl. Physiol. 68: 1514-1527, 1990). Here we describe the methods used and the responses of single components of the larger model. Perivascular pressure is modeled as a function of intravascular and transpulmonary pressures (Pv and Ptp, respectively) and vessel length as a function of lung volume. These and the relationship between vascular area (A) and transmural pressure (Ptm) were modeled primarily from the dog data of Smith and Mitzner (J. Appl. Physiol. 48: 450-467, 1980). Vasomotor tone is modeled as a radial collapsing pressure (Pt) in the same plane as Ptm. In view of lack of information about the relationship between Pt and A for a given active state, different patterns were assumed that span a wide range of possible relationships. The P-F and Pin-Pout relationships of single vessels were very similar to those reported for the entire intact circulation. Of note, the slope of the Pin-Pout relationship in the low Pout range (0-5 Torr) was very low (less than 0.25) and increased gradually with Pout toward unity. Vasomotor tone caused an apparent parallel shift in the P-F relationship in the physiological flow range of the dog (2-8 l/min) regardless of the pattern used to model the Pt vs. A relationship; different patterns affected the P-F relationship only over the low flow range before the parallel shift was established.

A mathematical model for measuring blood flow in skeletal muscle with the microdialysis ethanol technique

1995 ◽  
Vol 79 (2) ◽  
pp. 648-659 ◽  
Author(s):  
F. Wallgren ◽  
G. Amberg ◽  
R. C. Hickner ◽  
U. Ekelund ◽  
L. Jorfeldt ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Blood Flow ◽  
Muscle Tissue ◽  
Theoretical Calculations ◽  
Microdialysis Probe ◽  
Flow Rates ◽  
Perfusate Flow ◽  
Wide Range ◽  
Theory And Experiments ◽  
Good Agreement

A theoretical analysis of the microdialysis ethanol technique in skeletal muscle is presented, and a model governing the transport of ethanol from the microdialysis probe to the capillaries in the muscle tissue is proposed. The model is derived under the assumption of a steady-state situation, and an analytical solution is found for the outflow-to-inflow ratio of ethanol in the perfusate. Theoretically calculated results are compared with experiments, and for at least one of the two probe types used good agreement is achieved in a wide range of blood flow and perfusate flow rates. The main uncertainty factor in the theoretical calculations is the diffusivity of ethanol in muscle tissue, and the value for best agreement between theory and experiments has been used. Error estimates show that for a constant relative error in the outflow-to-inflow ratio of ethanol in the perfusate, low perfusate flow rates give better predictions of the blood flow.

Vasoconstriction is amplified by autoregulation during vasoconstrictor-induced hypertension

1988 ◽  
Vol 254 (4) ◽  
pp. H709-H718 ◽  
Author(s):  
G. A. Meininger ◽  
J. P. Trzeciakowski
Keyword(s):  
Blood Flow ◽  
Arterial Pressure ◽  
Vascular Resistance ◽  
Dose Response ◽  
Flow Curve ◽  
Perfusion Pressure ◽  
Low Doses ◽  
Ang Ii ◽  
Local Pressure ◽  
Pressure Flow

This study investigated the degree to which autoregulation of blood flow interacts with vasoconstrictors to determine vascular resistance. Anesthetized rats were instrumented with a Doppler flow probe on the superior mesenteric artery (SMA) to measure blood flow and for calculation of vascular resistance. An adjustable occluder was placed on the SMA to set local perfusion pressure at values independent of mean arterial pressure (MAP) even when MAP was increased by the vasoconstrictors. Infusion of angiotensin II (ANG II, 50-1,247 ng.kg-1.min-1) produced a dose-dependent rightward shift in the intestinal pressure-flow relationship and elevated MAP from 85 to 127 mmHg. Low doses of phenylephrine (PE, 2.5-12.4 micrograms.kg-1.min-1) failed to shift the pressure-flow curve but did increase arterial pressure from 83 to 102 mmHg. At higher doses (25-62 micrograms.kg-1.min-1), PE also shifted the pressure-flow curve to the right. Maintaining local perfusion pressure at different values during the infusion of ANG II or PE produced a family of dose-response curves, with each exhibiting a different maximum change in resistance. When local pressure was permitted to increase with MAP, the composite dose-response curve for resistance that was obtained reflected the influence of the rise in local pressure (i.e., auto-regulation) and vasoconstrictor dose. At low doses of PE the increase in vascular resistance was attributable solely to an autoregulatory response related to the rise in MAP and not due to the constrictor effects of PE. Thus these data indicate that the rise in MAP accompanying systemic infusion of a vasoconstrictor stimulates autoregulation to amplify the local increase in vascular resistance.

The Pressure-Flow Relation for Plasma in Whole Organ Skeletal Muscle and Its Experimental Verification

1991 ◽  
Vol 113 (4) ◽  
pp. 452-457 ◽  
Author(s):  
Don W. Sutton ◽  
Geert W. Schmid-Scho¨nbein
Keyword(s):  
Skeletal Muscle ◽  
Blood Vessels ◽  
Gracilis Muscle ◽  
Low Flow ◽  
Third Order ◽  
Fixed Tissue ◽  
Pressure Flow ◽  
Flow Rates ◽  
Order Polynomial ◽  
Artificial Plasma

The whole-organ pressure-flow relation in resting rat skeletal muscle is examined for the flow of plasma. Due to the small size of the blood vessels in this organ, inertia and convective forces in the blood are negligible and viscous forces dominate. Direct measurements in the past have shown that skeletal muscle blood vessels are distensible. Theoretical formulations based on these measurements lead to a third order polynomial model for the pressure-flow relation. The purpose of the current study is to examine this relation experimentally in an isolated muscle organ. A high precision feedback controlled pump is used to perfuse artificial plasma into the vasodilated rat gracilis muscle. The results indicate that the pressure-flow curve in this tissue is nonlinear in the low flow region and almost linear at physiological flow rates, following closely the third order polynomial function. Vessel fixation with glutaraldehyde causes the curves to become linear at all pressures, indicating that vessel distention is the primary mechanism causing the nonlinearity. Furthermore, the resistance of the post-fixed tissue is determined by the pressure at which the fixative is perfused. At fixation pressures below 10 mmHg, the resistance is three times higher than in vessels fixed at normal physiological pressures. Dextran (229,000 Dalton) is used to obtain Newtonian perfusates at different viscosities. The pressure-flow relation is found to be linearly dependent on viscosity for all flow rates. Skeletal muscle has multiple arterial inflows. Separate perfusion of the two major arterial feeders in the rat gracilis muscle show that for low pressures the flow at each feeder is dependent on the pressure at the opposite feeder, whereas at normal pressures the flow becomes independent of the opposite feeder pressure. The hemodynamic resistance in plasma perfused vasodilated skeletal muscle depends on vessel distensibility, plasma viscosity, and can be closely modeled by a third order polynomial relation.

Effects of external pressure loading on human skin blood flow measured by 133Xe clearance

1976 ◽  
Vol 40 (4) ◽  
pp. 597-600 ◽  
Author(s):  
G. A. Holloway ◽  
C. H. Daly ◽  
D. Kennedy ◽  
J. Chimoskey
Keyword(s):  
Blood Flow ◽  
Skin Blood Flow ◽  
Flow Curve ◽  
Human Subjects ◽  
Normal Skin ◽  
Reactive Hyperemia ◽  
External Pressure ◽  
Pressure Loading ◽  
Pressure Flow ◽  
Forearm Skin

Forearm skin blood flow was measured during external pressure loading in normal human subjects using 133Xe washout from intracutaneous injection sites. Pressures ranging between 5 and 150 mmHg were applied through a 3-cm-diameter disc placed over the site of flow determination. The pressure was maintained constant by a servo-controlled loading mechanism. Flow decreased with pressures from 5 to 10 and 30 to 150 mmHg, but remained constant with pressures from 10 to 30 mmHg. Reactive hyperemia occurred following removal of pressures of 90 mmHg or greater, but did not occur following removal of lower pressures. The pressure-flow curve for parasacral skin of paraplegic subjects closely paralleled the pressure-flow curve of normal skin at pressures tested: 5–15 mmHg. These data are interpreted to demonstrate autoregulation of skin blood flow. Autoregulation in parasacral skin of paraplegic subjects suggests a peripheral mechanism. The occurrence of hyperemia at pressures which exceed the ability of skin to autoregulate suggests that both autoregulation and post occlusion hyperemia may have the same mechanism.

Pressure-flow relations of human blood in hollow fibers at low flow rates

1965 ◽  
Vol 20 (5) ◽  
pp. 954-967 ◽  
Author(s):  
E. W. Merrill ◽  
A. M. Benis ◽  
E. R. Gilliland ◽  
T. K. Sherwood ◽  
E. W. Salzman
Keyword(s):  
Blood Flow ◽  
Shear Stress ◽  
Surface Characteristics ◽  
Ringer Solution ◽  
Hollow Fibers ◽  
Low Flow ◽  
Blood Capillary ◽  
Rotational Viscometer ◽  
Pressure Flow ◽  
Drop Flow

Suspensions of human red cells in citrated plasma, in Ringer solution, and in Ringer solution containing albumin were passed through straight and curved glass and plastic hollow fibers (diameter range, 100–1,000 μ). Pressure-flow relations were measured over the pressure range of 0.1– 800 mm water, corresponding to a shear stress range of 0.01– 80 dynes/cm2. The suspensions were tested simultaneously in a rotational viscometer. It was found that red cell suspensions exhibit a yield shear stress only if the plasma protein fibrinogen is present. Experimental pressure-flow data in hollow fibers were in excellent agreement with rotational viscometer measurements and with analytical predictions based on the assumptions that blood flows as a homogeneous continuum and that the velocity at the wall is zero. Effects of tube surface characteristics and curvature on the pressure drop-flow rate relation were not discernible. microcirculation models; model blood flow; yield stress of blood; capillary blood flow and viscometry; fibrinogen and blood flow in hollow fibers; non-Newtonian flow of blood in hollow fibers Submitted on July 20, 1964

Increased myogenic responsiveness of skeletal muscle arterioles with juvenile growth

2008 ◽  
Vol 294 (5) ◽  
pp. H2344-H2351 ◽  
Author(s):  
Julie Balch Samora ◽  
Jefferson C. Frisbee ◽  
Matthew A. Boegehold
Keyword(s):  
Skeletal Muscle ◽  
Blood Flow ◽  
Structural Changes ◽  
Tissue Blood Flow ◽  
Juvenile Growth ◽  
Sprague Dawley ◽  
Wide Range ◽  
Old Rats ◽  
Myogenic Activity

Previous studies from this laboratory suggest that during juvenile growth, structural changes in the arteriolar network are accompanied by changes in some of the mechanisms responsible for regulation of tissue blood flow. To test the hypothesis that arteriolar myogenic behavior is altered with growth, we studied gracilis muscle arterioles isolated from Sprague-Dawley rats at two ages: 21–28 and 42–49 days. When studied at their respective in vivo pressures, the myogenic index (instantaneous slope of the active pressure-diameter curve) of arterioles from 42–49-day-old rats was more negative than that of arterioles from 21–28-day-old rats, indicating greater myogenic responsiveness. Endothelial denudation, or prostaglandin H2 (PGH2)/thromboxane A2 (TxA2) receptor antagonism without denudation, significantly reduced the myogenic responsiveness of arterioles from the older rats over a wide range of pressures but had no consistent effects on the myogenic responsiveness of arterioles from the younger rats. The heme oxygenase inhibitor chromium (III) mesoporphyrin IX chloride had no effect on the myogenic activity of arterioles from either age group. These findings indicate that microvascular growth in young animals is accompanied by an increase in the myogenic behavior of arterioles, possibly because PGH2 or TxA2 assumes a role in reinforcing myogenic activity over this period. As a result, the relative contribution of myogenic activity to blood flow regulation in skeletal muscle may increase during rapid juvenile growth.

Hemodynamics at low flow in resting vasodilated rat skeletal muscle

1989 ◽  
Vol 257 (5) ◽  
pp. H1419-H1427 ◽  
Author(s):  
D. W. Sutton ◽  
G. W. Schmid-Schonbein
Keyword(s):  
Skeletal Muscle ◽  
Steady State ◽  
Cell Aggregation ◽  
Single Step ◽  
Low Flow ◽  
Collateral Flow ◽  
Pressure Flow ◽  
Harmonic Flow ◽  
Central Circulation ◽  
Zero Flow

The low flow arterial pressure-flow relationship and zero-flow pressure (ZFP) are investigated in the hemodynamically isolated gracilis muscle using a high precision pump. The muscle is kept in situ with dilated vasculature. During steady-state perfusion, using a plasma-like medium, the pressure-flow curve is nonlinear with positive arterial ZFP of 3.5-12 mm Hg when normal central circulation pressure is present. When the central circulation is stopped the ZFP reduces to zero. Addition of nonaggregated red blood cells (RBCs) results in no significant increase in the ZFP; however, introduction of aggregated RBCs (with dextran, 77 kDa) causes a 9.4 +/- 1.2 mmHg elevation. The positive ZFPs observed using plasma-like and dispersed RBC perfusions are found to be caused by a back pressure from the central circulation via collateral arterioles. A single-step reduction of the arterial flow rate from a finite value to zero results in a ZFP, which decreases for more than a minute before steady state is reached. During harmonic flow inputs with oscillations down to zero flow, an increase in the ZFP is detected near 0.09 Hz and continues to rise up to the test limit of 10 Hz. Our results suggests that in vasodilated skeletal muscle three independent mechanisms exist, collateral flow, cell aggregation, and unsteady perfusion, which may cause a positive arterial ZFP.

Effect of changes in blood flow, norepinephrine, and pH on oxygen uptake by resting skeletal muscle

1980 ◽  
Vol 58 (1) ◽  
pp. 93-96 ◽  
Author(s):  
C. K. Chapler ◽  
W. N. Stainsby ◽  
L. B. Gladden
Keyword(s):  
Skeletal Muscle ◽  
Blood Flow ◽  
Oxygen Uptake ◽  
Muscle Blood Flow ◽  
Sampling Period ◽  
Low Flow ◽  
Muscle Oxygen ◽  
Norepinephrine Infusion ◽  
Infusion Of Norepinephrine ◽  
Muscle Oxygen Uptake

The purpose of this study was to examine the effects of norepinephrine infusion alone and during alkalosis on oxygen uptake in the dog gastrocnemius-plantaris muscle group under conditions of constant muscle blood flow. The animals were not cold acclimatized. Blood flow was pump controlled, alkalosis was produced by hyperventilation, and norepinephrine was infused intravenously at a rate of 1–1.5 μg/kg per minute. Alkalosis had no effect either alone or in combination with changes in blood flow. Similarly, changing blood flow from a low (0.10 ± 0.02 mL/g muscle per minute (mean ± SE)) to a high (0.34 ± 0.04 mL/g muscle per minute) rate did not alter resting oxygen uptake. Norepinephrine caused an average increase of about 30% in resting muscle oxygen uptake which was sustained for the 15-min sampling period during low flow - norepinephrine infusion and during the low and high blood flow - norepinephrine - alkalosis sampling periods. Norepinephrine infusion during the period of high muscle blood flow without alkalosis resulted in a transient increase followed by a decrease in muscle oxygen uptake. The data demonstrated that infusion of norepinephrine increased skeletal muscle oxygen uptake in "non-cold-acclimatized" dogs at low constant muscle blood flow. Further, without alkalosis, the norepinephrine effect at high flow was transient.

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