Evaluation of the Parallel Conductor Theory for Measuring Human Limb Blood Flow by Electrical Admittance Plethysmography

1982 ◽  
Vol BME-29 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Hideaki Shimazu ◽  
Ken-Ichi Yamakoshi ◽  
Tatsuo Togawa ◽  
Masakazu Fukuoka ◽  
Hiroshi Ito
Keyword(s):  
Blood Flow ◽  
Limb Blood Flow ◽  
Electrical Admittance ◽  
Admittance Plethysmography ◽  
Parallel Conductor ◽  
Human Limb

Admittance plethysmography for accurate measurement of human limb blood flow

1978 ◽  
Vol 235 (6) ◽  
pp. H821-H829 ◽  
Author(s):  
K. I. Yamakoshi ◽  
H. Shimazu ◽  
T. Togawa ◽  
H. Ito
Keyword(s):  
Blood Flow ◽  
Limb Blood Flow ◽  
Admittance Plethysmography ◽  
Human Limb

scholarly journals Human muscle length-dependent changes in blood flow

2012 ◽  
Vol 112 (4) ◽  
pp. 560-565 ◽  
Author(s):  
John McDaniel ◽  
Stephen J. Ives ◽  
Russell S. Richardson
Keyword(s):  
Blood Flow ◽  
Knee Joint ◽  
Joint Angle ◽  
Muscle Blood Flow ◽  
Muscle Length ◽  
Limb Blood Flow ◽  
Knee Joint Angle ◽  
Femoral Blood Flow ◽  
Femoral Blood ◽  
Cyclic Changes

Although a multitude of factors that influence skeletal muscle blood flow have been extensively investigated, the influence of muscle length on limb blood flow has received little attention. Thus the purpose of this investigation was to determine if cyclic changes in muscle length influence resting blood flow. Nine healthy men (28 ± 4 yr of age) underwent a passive knee extension protocol during which the subjects' knee joint was passively extended and flexed through 100–180° knee joint angle at a rate of 1 cycle per 30 s. Femoral blood flow, cardiac output (CO), heart rate (HR), stroke volume (SV), and mean arterial pressure (MAP) were continuously recorded during the entire protocol. These measurements revealed that slow passive changes in knee joint angle did not have a significant influence on HR, SV, MAP, or CO; however, net femoral blood flow demonstrated a curvilinear increase with knee joint angle ( r2 = 0.98) such that blood flow increased by ∼90% (125 ml/min) across the 80° range of motion. This net change in blood flow was due to a constant antegrade blood flow across knee joint angle and negative relationship between retrograde blood flow and knee joint angle ( r2 = 0.98). Thus, despite the absence of central hemodynamic changes and local metabolic factors, blood flow to the leg was altered by changes in muscle length. Therefore, when designing research protocols, researchers need to be cognizant of the fact that joint angle, and ultimately muscle length, influence limb blood flow.

Cardiac Output Changes in Newborns With Hyperbilirubinemia Treated With Phototherapy

PEDIATRICS ◽  
1985 ◽  
Vol 76 (6) ◽  
pp. 918-921
Author(s):  
Frans J. Walther ◽  
Paul Y. K. Wu ◽  
Bijan Siassi
Keyword(s):  
Blood Flow ◽  
Cardiac Output ◽  
Stroke Volume ◽  
Skin Blood Flow ◽  
Peripheral Blood ◽  
Cardiovascular Effects ◽  
Tissue Perfusion ◽  
Peripheral Blood Flow ◽  
Limb Blood Flow ◽  
Term Infants

Phototherapy is known to increase peripheral blood flow in neonates, but information on the associated cardiovascular effects is not available. Using pulsed Doppler echocardiography we evaluated cardiac output and stroke volume in 12 preterm and 13 term neonates during and after phototherapy. We concomitantly measured arterial limb blood flow by strain gauge plethysmography and skin blood flow by photoplethysmography. Cardiac output decreased by 6% due to reduced stroke volume during phototherapy, whereas total limb blood flow and skin blood flow increased by 38% and 41%, respectively. Peripheral blood flow increments tended to be higher in the preterm than in the term infants. The reduced stroke volume during phototherapy may be an expression of reduced activity of the newborn during phototherapy. For healthy neonates the reduction in cardiac output is minimal, but for sick infants with reduced cardiac output, this reduction may further aggravate the decrease in tissue perfusion.

Limb blood flow and tissue perfusion during exercise with blood flow restriction

2018 ◽  
Vol 119 (2) ◽  
pp. 377-387 ◽  
Author(s):  
Matthew A. Kilgas ◽  
John McDaniel ◽  
Jon Stavres ◽  
Brandon S. Pollock ◽  
Tyler J. Singer ◽  
...  
Keyword(s):  
Blood Flow ◽  
Tissue Perfusion ◽  
Blood Flow Restriction ◽  
Limb Blood Flow ◽  
Flow Restriction

scholarly journals Stimulatory effect of insulin on creatine accumulation in human skeletal muscle

1998 ◽  
Vol 275 (6) ◽  
pp. E974-E979 ◽  
Author(s):  
G. R. Steenge ◽  
J. Lambourne ◽  
A. Casey ◽  
I. A. Macdonald ◽  
P. L. Greenhaff
Keyword(s):  
Blood Flow ◽  
Human Skeletal Muscle ◽  
Insulin Infusion ◽  
Forearm Blood Flow ◽  
Dry Mass ◽  
Limb Blood Flow ◽  
Time Points ◽  
Creatine Transport ◽  
Total Creatine ◽  
Muscle Creatine

This study investigated the effect of insulin on plasma and muscle creatine accumulation and limb blood flow in humans after creatine administration. Seven men underwent a 300-min euglycemic insulin clamp combined with creatine administration on four separate occasions. Insulin was infused at rates of 5, 30, 55, or 105 mU ⋅ m−2 ⋅ min−1, and on each occasion 12.4 g creatine was administered. During infusion of insulin at rates of 55 and 105 mU ⋅ m−2 ⋅ min−1, muscle total creatine concentration increased by 4.5 ± 1.4 ( P < 0.05) and 8.3 ± 1.0 mmol/kg dry mass ( P < 0.05), and plasma creatine concentrations were lower at specific time points compared with the 5 mU ⋅ m−2 ⋅ min−1infusion rate. The magnitude of increase in calf blood flow (plethysmography) was the same irrespective of the rate of insulin infusion, and forearm blood flow increased to the same extent as the three highest infusion rates. These findings demonstrate that insulin can enhance muscle creatine accumulation in humans but only when present at physiologically high or supraphysiological concentrations. This response is likely to be the result of an insulin-mediated increase in muscle creatine transport rather than creatine delivery.

Effects of prior heavy-intensity exercise during single-leg knee extension on v̇o2 kinetics and limb blood flow

2005 ◽  
Vol 99 (4) ◽  
pp. 1462-1470 ◽  
Author(s):  
Nicole D. Paterson ◽  
John M. Kowalchuk ◽  
Donald H. Paterson
Keyword(s):  
Blood Flow ◽  
Phase Ii ◽  
Time Course ◽  
Muscle Blood Flow ◽  
Knee Extension ◽  
Phase Iii ◽  
Limb Blood Flow ◽  
Heavy Exercise ◽  
Pulsed Wave Doppler ◽  
Young Subjects

The effects of prior heavy-intensity exercise on O2 uptake (V̇o2) kinetics of a second heavy exercise may be due to vasodilation (associated with metabolic acidosis) and improved muscle blood flow. This study examined the effect of prior heavy-intensity exercise on femoral artery blood flow (Qleg) and its relationship with V̇o2 kinetics. Five young subjects completed five to eight repeats of two 6-min bouts of heavy-intensity one-legged, knee-extension exercise separated by 6 min of loadless exercise. V̇o2 was measured breath by breath. Pulsed-wave Doppler ultrasound was used to measure Qleg. V̇o2 and blood flow velocity data were fit using a monoexponential model to identify phase II and phase III time periods and estimate the response amplitudes and time constants (τ). Phase II V̇o2 kinetics was speeded on the second heavy-intensity exercise [mean τ (SD), 29 ( 10 ) s to 24 ( 10 ) s, P < 0.05] with no change in the phase II (or phase III) amplitude. Qleg was elevated before the second exercise [1.55 (0.34) l/min to 1.90 (0.25) l/min, P < 0.05], but the amplitude and time course [τ, 25 ( 13 ) s to 35 ( 13 ) s] were not changed, such that throughout the transient the Qleg (and ΔQleg/ΔV̇o2) did not differ from the prior heavy exercise. Thus V̇o2 kinetics were accelerated on the second exercise, but the faster kinetics were not associated with changes in Qleg. Thus limb blood flow appears not to limit V̇o2 kinetics during single-leg heavy-intensity exercise nor to be the mechanism of the altered V̇o2 response after heavy-intensity prior exercise.

The effect of angiotensin I and II on hind-limb blood flow in sheep

1971 ◽  
Vol 23 (6) ◽  
pp. 466-468 ◽  
Author(s):  
E. C. Osborn ◽  
G. Tildesley ◽  
K. G. Leach ◽  
R. F. Mahler
Keyword(s):  
Blood Flow ◽  
Hind Limb ◽  
Limb Blood Flow ◽  
Angiotensin I
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