o_1977r8vv9vk1ts2ms0kd8pksa.pdf

a Chapter 5 Venous Hemodynamics 65
The vibration of the heart is also transmitted into the
liver tissue and beyond and may have impact on the
venous flow. Vortices, like whirls in a river, may occur
in large veins and cause velocity variation recorded
in the Doppler shift (Fig. 5.16). In some cases, information
on pulse-wave direction, time of the pulse
and details of its form does permit the discrimination
between sources.
It follows from what is presented in this section
that pulsatile venous flow, both in precordial veins
and in peripheral veins, such as the umbilical vein
and intracranial veins, is determined by cardiac function
and the local physical properties of the vasculature.
All determinants vary with gestational age. Unless
these facts are taken into account, we shall not
be able to use the diagnostic techniques of venous
Doppler recordings to their full potential, but face a
commonly occurring risk of misinterpretation.
Fig. 5.15. Doppler recording in the ductus venosus (a) and
the left portal branch (b) in a fetus of 25 weeks gestation
with placental compromise. For anatomical references see
also Fig. 5.14. The ductus venosus recording shows an
augmented atrial contraction wave (A) reaching the zero
line (pulse wave and blood flow have opposite directions).
The same wave recorded in the left portal branch is a peak
(A in b) since pulse wave now has the same direction as
the blood flow; thus, the entire waveform during the cardiac
cycle is found to be reciprocal (mirror image) at the two
sites. D diastolic peak, S systolic peak. (From [49])
Fig. 5.16. Vortex formation (whirls) recorded as velocity
variation, which mimics pulsation, in the umbilical vein.
Such whirls tend to occur in large bore vessels with steady
velocity, particularly if there is a diameter variation, curvature
or bifurcation. The velocity usually does not fit with
the heart rate. (From [29])
References
1. Nichols WW, O'Rourke MF (1998) McDonald's blood
flow in arteries. Theoretical, experimental and clinical
principles. Arnold, London, p 564
2. Burns PN (1995) Hemodynamics. In: Taylor KJW,
Burns PN, Wells PNT (eds) Clinical applications of
Doppler ultrasound. Raven Press, New York, pp 35±44
3. Fung YC (1984) Biodynamics. Springer, Berlin Heidelberg
New York
4. Fung YC (1984) Biomechanics. Springer, Berlin Heidelberg
New York
5. Fung YC (1993) Biomechanics. Springer, Berlin Heidelberg
New York
6. Pennati G, Bellotti M, Gasperi C de, Rognoni G (2004)
Spatial velocity profile changes along the cord in normal
human fetuses: can these affect Doppler measurements
of venous umbilical blood flow? Ultrasound Obstet
Gynecol 23:131±137
7. Gill RW (1979) Pulsed Doppler with B-mode imaging
for quantitative blood flow measurement. Ultrasound
Med Biol 5:223±235
8. Eik-Nes SH, MarÉ—l K, Brubakk AO, Ulstein M (1980)
Ultrasonic measurements of human fetal blood flow in
aorta and umbilical vein: Influence of fetal breathing
movements. In: Kurjak A (ed) Recent advances in ultrasound
diagnosis. Proceedings of the International
Symposium on Recent Advances in Ultrasound Diagnosis,
vol 2. Excerpta Medica, Amsterdam, pp 233±240
9. Jouppila P, Kirkinen P, Puukka R (1986) Correlation
between umbilical vein blood flow and umbilical blood
viscosity in normal and complicated pregnancies. Arch
Gynecol 237:191±197
10. Kiserud T, Eik-Nes SH, Blaas H-G, Hellevik LR, Simensen
B (1994) Ductus venosus blood velocity and the
umbilical circulation in the seriously growth retarded
fetus. Ultrasound Obstet Gynecol 4:109±114
11. Tchirikov M, Rybakowski C, Hçnecke B, Schræder HJ
(1998) Blood flow through the ductus venosus in singleton
and multifetal pregnancies and in fetuses with
intrauterine growth retardation. Am J Obstet Gynecol
178:943±949
12. Kiserud T, Rasmussen S, Skulstad SM (2000) Blood
flow and degree of shunting through the ductus venosus
in the human fetus. Am J Obstet Gynecol 182:147±
153
13. Bellotti M, Pennati G, Gasperi C de, Battaglia FC, Ferrazzi
E (2000) Role of ductus venosus in distribution