Pulse wave analysis on fingertip arterial pressure: effects of age, gender and stressors on reflected waves and their relation to brachial and femoral artery blood flow

The windkessel function of the arterial system converts the intermittent action of the heart into more continuous microcirculatory blood flow during diastole via the return of elastic energy stored in the walls of the arteries during systole. Might the same phenomenon occur regionally within the arterial system during tilting owing to regional differences in local arterial pressure imposed by gravity? We sought to test the hypothesis that during tilt-back from a head-up posture, the return of stored elastic energy in leg arteries would work to slow, or perhaps transiently reverse, the flow of blood in the femoral artery. Femoral artery blood flow and arterial pressure were recorded during tilt back from a 30° head-up posture to supine (∼0.5 G) in young, healthy subjects ( n = 7 males and 3 females) before and during clonidine infusion. During control (no drug) conditions femoral artery blood flow ceased for an entire heart beat during tilt-back. During clonidine infusion femoral artery blood flow reversed for at least one entire heart beat during tilt-back, i.e., blood flow in the retrograde direction in the femoral artery from the leg into the abdomen. Thus substantial capacitive effects of tilting on leg blood flow occur in humans during mild changes in posture.

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Kinetics of V̇o2 and femoral artery blood flow during heavy-intensity, knee-extension exercise

Journal of Applied Physiology ◽

10.1152/japplphysiol.00707.2004 ◽

2005 ◽

Vol 99 (2) ◽

pp. 683-690 ◽

Cited By ~ 14

Author(s):

Nicole D. Paterson ◽

John M. Kowalchuk ◽

Donald H. Paterson

Keyword(s):

Blood Flow ◽

Femoral Artery ◽

Time Course ◽

Slow Component ◽

Knee Extension ◽

Artery Blood Flow ◽

Phase 2 ◽

Femoral Artery Blood Flow ◽

Knee Extension Exercise ◽

Kinetics Of

It has been suggested that, during heavy-intensity exercise, O2 delivery may limit oxygen uptake (V̇o2) kinetics; however, there are limited data regarding the relationship of blood flow and V̇o2 kinetics for heavy-intensity exercise. The purpose was to determine the exercise on-transient time course of femoral artery blood flow (Q̇leg) in relation to V̇o2 during heavy-intensity, single-leg, knee-extension exercise. Five young subjects performed five to eight repeats of heavy-intensity exercise with measures of breath-by-breath pulmonary V̇o2 and Doppler ultrasound femoral artery mean blood velocity and vessel diameter. The phase 2 time frame for V̇o2 and Q̇leg was isolated and fit with a monoexponent to characterize the amplitude and time course of the responses. Amplitude of the phase 3 response was also determined. The phase 2 time constant for V̇o2 of 29.0 s and time constant for Q̇leg of 24.5 s were not different. The change (Δ) in V̇o2 response to the end of phase 2 of 0.317 l/min was accompanied by a ΔQ̇leg of 2.35 l/min, giving a ΔQ̇leg-to-ΔV̇o2 ratio of 7.4. A slow-component V̇o2 of 0.098 l/min was accompanied by a further Q̇leg increase of 0.72 l/min (ΔQ̇leg-to-ΔV̇o2 ratio = 7.3). Thus the time course of Q̇leg was similar to that of muscle V̇o2 (as measured by the phase 2 V̇o2 kinetics), and throughout the on-transient the amplitude of the Q̇leg increase achieved (or exceeded) the Q̇leg-to-V̇o2 ratio steady-state relationship (ratio ∼4.9). Additionally, the V̇o2 slow component was accompanied by a relatively large rise in Q̇leg, with the increased O2 delivery meeting the increased V̇o2. Thus, in heavy-intensity, single-leg, knee-extension exercise, the amplitude and kinetics of blood flow to the exercising limb appear to be closely linked to the V̇o2 kinetics.

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Quantitative pulsed Doppler measurement of common femoral artery blood flow variables during postocclusive reactive hyperemia

Journal of Clinical Ultrasound ◽

10.1002/jcu.1870140302 ◽

1986 ◽

Vol 14 (3) ◽

pp. 165-170 ◽

Cited By ~ 5

Author(s):

C. Marquis ◽

J.-J. Meister ◽

E. Mower ◽

R. Mosimann

Keyword(s):

Blood Flow ◽

Femoral Artery ◽

Reactive Hyperemia ◽

Common Femoral Artery ◽

Artery Blood Flow ◽

Pulsed Doppler ◽

Doppler Measurement ◽

Femoral Artery Blood Flow ◽

Flow Variables ◽

Postocclusive Reactive Hyperemia

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Ultrasound Doppler estimates of femoral artery blood flow during dynamic knee extensor exercise in humans

Journal of Applied Physiology ◽

10.1152/jappl.1997.83.4.1383 ◽

1997 ◽

Vol 83 (4) ◽

pp. 1383-1388 ◽

Cited By ~ 188

Author(s):

G. Rådegran

Keyword(s):

Blood Flow ◽

Femoral Artery ◽

Coefficient Of Variation ◽

Knee Extensor ◽

Dynamic Exercise ◽

Artery Blood Flow ◽

Ultrasound Doppler ◽

Femoral Artery Blood Flow ◽

Human Limb ◽

Exercise In Humans

Rådegran, G. Ultrasound Doppler estimates of femoral artery blood flow during dynamic knee extensor exercise in humans. J. Appl. Physiol.83(4): 1383–1388, 1997.—Ultrasound Doppler has been used to measure arterial inflow to a human limb during intermittent static contractions. The technique, however, has neither been thoroughly validated nor used during dynamic exercise. In this study, the inherent problems of the technique have been addressed, and the accuracy was improved by storing the velocity tracings continuously and calculating the flow in relation to the muscle contraction-relaxation phases. The femoral arterial diameter measurements were reproducible with a mean coefficient of variation within the subjects of 1.2 ± 0.2%. The diameter was the same whether the probe was fixed or repositioned at rest (10.8 ± 0.2 mm) or measured during dynamic exercise. The blood velocity was sampled over the width of the diameter and the parabolic velocity profile, since sampling in the center resulted in an overestimation by 22.6 ± 9.1% ( P< 0.02). The femoral arterial Doppler blood flow increased linearly ( r = 0.997, P < 0.001) with increasing load [Doppler blood flow = 0.080 ⋅ load (W) + 1.446 l/min] and was correlated positively with simultaneous thermodilution venous outflow measurements ( r = 0.996, P < 0.001). The two techniques were linearly related (Doppler = thermodilution ⋅ 0.985 + 0.071 l/min; r = 0.996, P < 0.001), with a coefficient of variation of ∼6% for both methods.

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