Fetal pulmonary venous blood flow velocities in a normal population and new calculated reference values

2016 ◽  
Vol 36 (11) ◽  
pp. 1033-1040 ◽  
Author(s):  
Franz Bahlmann ◽  
Ralph Gallinat ◽  
Monica Schmidt-Fittschen ◽  
Ammar Al Naimi ◽  
Iris Reinhard ◽  
...  
Keyword(s):  
Blood Flow ◽  
Reference Values ◽  
Normal Population ◽  
Venous Blood ◽  
Venous Blood Flow ◽  
Blood Flow Velocities ◽  
Flow Velocities

Reference values of ductus venosus blood flow velocities and waveform indices from 10 to 20�weeks of gestation

2004 ◽  
Vol 269 (3) ◽  
pp. 199-204 ◽  
Author(s):  
R. Axt-Fliedner ◽  
S. Diler ◽  
T. Georg ◽  
M. Friedrich ◽  
K. Diedrich
Keyword(s):  
Blood Flow ◽  
Reference Values ◽  
Ductus Venosus ◽  
Blood Flow Velocities ◽  
Flow Velocities

The Effects of External Compression on Venous Blood Flow and Tissue Deformation in the Lower Leg

1999 ◽  
Vol 121 (6) ◽  
pp. 557-564 ◽  
Author(s):  
Guohao Dai ◽  
J. P. Gertler ◽  
R. D. Kamm
Keyword(s):  
Blood Flow ◽  
Venous Pressure ◽  
Venous Blood ◽  
Shear Stresses ◽  
Venous Blood Flow ◽  
Element Analysis ◽  
Uniform Compression ◽  
External Compression ◽  
Typical Application ◽  
Flow Velocities

External pneumatic compression of the lower legs is effective as prophylaxis against deep vein thrombosis. In a typical application, inflatable cuffs are wrapped around the patient’s legs and periodically inflated to prevent stasis, accelerate venous blood flow, and enhance fibrinolysis. The purpose of this study was to examine the stress distribution within the tissues, and the corresponding venous blood flow and intravascular shear stress with different external compression modalities. A two-dimensional finite element analysis (FEA) was used to determine venous collapse as a function of internal (venous) pressure and the magnitude and spatial distribution of external (surface) pressure. Using the one-dimensional equations governing flow in a collapsible tube and the relations for venous collapse from the FEA, blood flow resulting from external compression was simulated. Tests were conducted to compare circumferentially symmetric (C) and asymmetric (A) compression and to examine distributions of pressure along the limb. Results show that A compression produces greater vessel collapse and generates larger blood flow velocities and shear stresses than C compression. The differences between axially uniform and graded-sequential compression are less marked than previously found, with uniform compression providing slightly greater peak flow velocities and shear stresses. The major advantage of graded-sequential compression is found at midcalf. Strains at the lumenal border are approximately 20 percent at an external pressure of 50 mmHg (6650 Pa) with all compression modalities.

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