scholarly journals OP19.11: Umbilical venous blood flow measurements: comparison between free and intra-abdominal portion

2009 ◽  
Vol 34 (S1) ◽  
pp. 124-124
Author(s):  
J. Carrillo ◽  
M. Yamamoto ◽  
D. Pedraza ◽  
H. Munoz ◽  
P. Valentini ◽  
...  
Keyword(s):  
Blood Flow ◽  
Venous Blood ◽  
Venous Blood Flow ◽  
Flow Measurements ◽  
Blood Flow Measurements ◽  
Abdominal Portion

Neuromuscular electrical stimulation for thromboprophylaxis: A systematic review

2015 ◽  
Vol 30 (9) ◽  
pp. 589-602 ◽  
Author(s):  
S Hajibandeh ◽  
S Hajibandeh ◽  
GA Antoniou ◽  
JRH Scurr ◽  
F Torella
Keyword(s):  
Systematic Review ◽  
Blood Flow ◽  
Electrical Stimulation ◽  
Venous Thromboembolism ◽  
Venous Blood ◽  
Neuromuscular Electrical Stimulation ◽  
Current Evidence ◽  
Venous Blood Flow ◽  
Flow Measurements ◽  
Blood Flow Measurements

Objective To evaluate the effect of neuromuscular electrical stimulation on lower limb venous blood flow and its role in thromboprophylaxis. Method Systematic review of randomised and non-randomised studies evaluating neuromuscular electrical stimulation, and reporting one or more of the following outcomes: incidence of venous thromboembolism, venous blood flow and discomfort profile. Results Twenty-one articles were identified. Review of these articles showed that neuromuscular electrical stimulation increases venous blood flow and is generally associated with an acceptable tolerability, potentially leading to good patient compliance. Ten comparative studies reported DVT incidence, ranging from 2% to 50% with neuromuscular electrical stimulation and 6% to 47.1% in controls. There were significant differences, among included studies, in terms of patient population, neuromuscular electrical stimulation delivery, diagnosis of venous thromboembolism and blood flow measurements. Conclusion Neuromuscular electrical stimulation increases venous blood flow and is well tolerated, but current evidence does not support a role for neuromuscular electrical stimulation in thromboprophylaxis. Randomised controlled trials are required to investigate the clinical utility of neuromuscular electrical stimulation in this setting.

Thigh oxygen uptake at the onset of intense exercise is not affected by a reduction in oxygen delivery caused by hypoxia

2012 ◽  
Vol 303 (8) ◽  
pp. R843-R849 ◽  
Author(s):  
Peter M. Christensen ◽  
Nikolai Baastrup Nordsborg ◽  
Lars Nybo ◽  
Stefan P. Mortensen ◽  
Mikael Sander ◽  
...  
Keyword(s):  
Blood Flow ◽  
Oxygen Uptake ◽  
Oxygen Delivery ◽  
Venous Blood ◽  
Knee Extensor ◽  
Intense Exercise ◽  
Muscle Lactate ◽  
Flow Measurements ◽  
Arterial Blood ◽  
Blood Flow Measurements

In response to hypoxic breathing most studies report slower pulmonary oxygen uptake (V̇o2) kinetics at the onset of exercise, but it is not known if this relates to an actual slowing of the V̇o2 in the active muscles. The aim of the present study was to evaluate whether thigh V̇o2 is slowed at the onset of intense exercise during acute exposure to hypoxia. Six healthy male subjects (25.8 ± 1.4 yr, 79.8 ± 4.0 kg, means ± SE) performed intense (100 ± 6 watts) two-legged knee-extensor exercise for 2 min in normoxia (NOR) and hypoxia [fractional inspired oxygen concentration (FiO2) = 0.13; HYP]. Thigh V̇o2 was measured by frequent arterial and venous blood sampling and blood flow measurements. In arterial blood, oxygen content was reduced ( P < 0.05) from 191 ± 5 ml O2/l in NOR to 180 ± 5 ml O2/l in HYP, and oxygen pressure was reduced ( P < 0.001) from 111 ± 4 mmHg in NOR to 63 ± 4 mmHg in HYP. Thigh blood flow was the same in NOR and HYP, and thigh oxygen delivery was consequently reduced ( P < 0.05) in HYP, but femoral arterial-venous oxygen difference and thigh V̇o2 were similar in NOR and HYP. In addition, muscle lactate release was the same in NOR and HYP, and muscle lactate accumulation during the first 25 s of exercise determined from muscle biopsy sampling was also similar (0.35 ± 0.07 and 0.36 ± 0.07 mmol·kg dry wt−1·s−1 in NOR and HYP). Thus the increase in thigh V̇o2 was not attenuated at the onset of intense knee-extensor exercise despite a reduction in oxygen delivery and pressure.

scholarly journals Arterio-Venous Branchial Blood Flow in the Atlantic Cod Gadus Morhua

1992 ◽  
Vol 165 (1) ◽  
pp. 73-84 ◽  
Author(s):  
LENA SUNDIN ◽  
STEFAN NILSSON
Keyword(s):  
Blood Flow ◽  
Cardiac Output ◽  
Atlantic Cod ◽  
Vascular System ◽  
Venous Blood ◽  
Venous Blood Flow ◽  
Venous Flow ◽  
Flow Measurements ◽  
Vasomotor Function

We have estimated the branchial venous blood flow in the Atlantic cod by direct single-crystal Doppler blood flow measurements in vivo. In the undisturbed animal, this flow amounts to 1.7 ml min−1 kg−1, which corresponds to about 8 % of the cardiac output. Studies of both an isolated perfused gill apparatus in situ and simultaneous measurements of cardiac output and branchial venous flow in vivo were made to assess the effects of some putative vasoregulatory substances. Adrenaline dilates the arterio-arterial pathway and constricts the arterio-venous pathway, thus decreasing branchial venous drainage. 5-Hydroxytryptamine (5-HT), in contrast, produced marked vasoconstriction in the arterio-arterial pathway of the branchial vasculature, increasing the branchial venous blood flow. Cholecystokinin-8 (CCK-8) and caerulein produced similar cardiovascular effects, with marked constriction of both arterio-arterial and arterio-venous pathways. The study demonstrates the ability of the vascular system of the gills to regulate the distribution of branchial blood flow, and summarizes the vasomotor effects of some substances with possible vasomotor function in the cod gills.

Limitations to vasodilatory capacity and V̇o2 max in trained human skeletal muscle

2007 ◽  
Vol 292 (5) ◽  
pp. H2491-H2497 ◽  
Author(s):  
Jeremy Barden ◽  
Lesley Lawrenson ◽  
Jennifer G. Poole ◽  
Jeannie Kim ◽  
D. Walter Wray ◽  
...  
Keyword(s):  
Skeletal Muscle ◽  
Blood Flow ◽  
Venous Blood ◽  
Knee Extensor ◽  
Quadriceps Muscle ◽  
Flow Measurements ◽  
Blood Flow Measurements ◽  
Increased Blood Flow ◽  
Venous Blood Sampling

To further explore the limitations to maximal O2 consumption (V̇o2 max) in exercise-trained skeletal muscle, six cyclists performed graded knee-extensor exercise to maximum work rate (WRmax) in hypoxia (12% O2), hyperoxia (100% O2), and hyperoxia + femoral arterial infusion of adenosine (ADO) at 80% WRmax. Arterial and venous blood sampling and thermodilution blood flow measurements allowed the determination of muscle O2 delivery and O2 consumption. At WRmax, O2 delivery rose progressively from hypoxia (1.0 ± 0.04 l/min) to hyperoxia (1.20 ± 0.09 l/min) and hyperoxia + ADO (1.33 ± 0.05 l/min). Leg V̇o2 max varied with O2 availability (0.81 ± 0.05 and 0.97 ± 0.07 l/min in hypoxia and hyperoxia, respectively) but did not improve with ADO-mediated vasodilation (0.80 ± 0.09 l/min in hyperoxia + ADO). Although a vasodilatory reserve in the maximally working quadriceps muscle group may have been evidenced by increased leg vascular conductance after ADO infusion beyond that observed in hyperoxia (increased blood flow but no change in blood pressure), we recognize the possibility that the ADO infusion may have provoked vasodilation in nonexercising tissue of this limb. Together, these findings imply that maximally exercising skeletal muscle may maintain some vasodilatory capacity, but the lack of improvement in leg V̇o2 max with significantly increased O2 delivery (hyperoxia + ADO), with a degree of uncertainty as to the site of this dilation, suggests an ADO-induced mismatch between O2 consumption and blood flow in the exercising limb.

Determinations of blood flow and shunting of 9- and 15-micrometer spheres in regional beds

1979 ◽  
Vol 237 (1) ◽  
pp. H25-H33 ◽  
Author(s):  
F. C. Fan ◽  
G. B. Schuessler ◽  
R. Y. Chen ◽  
S. Chien
Keyword(s):  
Blood Flow ◽  
Portal Vein ◽  
Venous Blood ◽  
Sampling Technique ◽  
Organ Blood Flow ◽  
Venous Sampling ◽  
Flow Measurements ◽  
Arterial Blood ◽  
Blood Flow Measurements ◽  
The Brain

In 17 pentobarbitalized dogs, the shunting of 15-micrometer and 9-micrometer microspheres was studied in the brain, myocardium, kidney, intestine, and lung. The veins of these organs were catheterized for constant blood withdrawal for 2 min by direct venipuncture. The ratio of microsphere radioactivity in the venous blood to that in the arterial blood gave the shunting of microspheres by the venous sampling technique. The 15-micrometer microspheres showed 2% or less shunting for all organs studied, whereas the 9-micrometer microspheres had shunting ranging from 3% in the coronary sinus to 24% in the portal vein. The shunting of 9-micrometer microspheres was also calculated from direct tissue counting, where the 15-micrometer spheres were considered to be completely entrapped. The results of direct tissue counting indicate that the 2-min venous sampling underestimates microsphere shunting. CO2 administration increased significantly the shunting of 9-micrometer spheres, whereas the shunting of 15-micrometer spheres determined by venous sampling remained less than 2%. Consideration of shunting indicates that the 15-micrometer microspheres might be more appropriate for regional organ blood flow measurements, including the myocardium.

scholarly journals Portable, non-invasive video imaging of retinal blood flow dynamics

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Kyoung-A Cho ◽  
Abhishek Rege ◽  
Yici Jing ◽  
Akash Chaurasia ◽  
Amit Guruprasad ◽  
...  
Keyword(s):  
Blood Flow ◽  
Cardiac Cycle ◽  
Venous Blood ◽  
Retinal Blood Flow ◽  
High Temporal Resolution ◽  
Venous Blood Flow ◽  
Head Region ◽  
Flow Measurements ◽  
Non Invasive ◽  
Temporal Waveform

AbstractRetinal blood flow (RBF) information has the potential to offer insight into ophthalmic health and disease that is complementary to traditional anatomical biomarkers as well as to retinal perfusion information provided by fluorescence or optical coherence tomography angiography (OCT-A). The present study was performed to test the functional attributes and performance of the XyCAM RI, a non-invasive imager that obtains and assesses RBF information. The XyCAM RI was installed and used in two different settings to obtain video recordings of the blood flow in the optic nerve head region in eyes of healthy subjects. The mean blood flow velocity index (BFVi) in the optic disc and in each of multiple arterial and venous segments was obtained and shown to reveal a temporal waveform with a peak and trough that correlates with a cardiac cycle as revealed by a reference pulse oximeter (correlation between respective peak-to-peak distances was 0.977). The intra-session repeatability of the XyCAM RI was high with a coefficient of variation (CV) of 1.84 ± 1.13% across both sites. Artery-vein comparisons were made by estimating, in a pair of adjacent arterial and venous segments, various temporal waveform metrics such as pulsatility index, percent time in systole and diastole, and change in vascular blood volume over a cardiac cycle. All arterial metrics were shown to have significant differences with venous metrics (p < 0.001). The XyCAM RI, therefore, by obtaining repeatable blood flow measurements with high temporal resolution, permits the differential assessment of arterial and venous blood flow patterns in the retina that may facilitate research into disease pathophysiology and biomarker development for diagnostics.

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