Advertisement

Umbilical flow distribution to the liver and the ductus venosus: An in vitro investigation of the fluid dynamic mechanisms in the fetal sheep

      Abstract

      OBJECTIVES: The study aimed to determine whether an inherent difference in vascular resistance between the liver and the ductus venosus influences the distribution of umbilical blood to the two sections of the circulation. STUDY DESIGN: Flow was measured in vitro in six fetal sheep liver preparations, perfused at varying pressures with saline solution or with blood of hematocrit 25% to 26% or 41% to 42%, with an occluded or open ductus venosus, at a temperature of 19° C to 21° C with likely absence of local control mechanisms. RESULTS: There was a linear relationship between pressure and flow through the liver, except at very low pressures when the linearity was broken. A closing pressure of 1 to 4 mm Hg was noted, lowest with saline solution and highest with hematocrit 42%. An open ductus venosus reduced overall resistance and brought down the closing pressure to <1 mm Hg. This also occurred during perfusion with high hematocrit. Thus at low pressures a proportionally greater fraction of umbilical flow was directed through the ductus venosus. CONCLUSIONS: The different physical properties of the portal vasculature and of the ductus venosus, pressure and viscosity, have a substantial impact on distribution of umbilical flow to the two parts of the circulation. Reduced umbilical venous pressure and increased hematocrit favor an increased fraction of flow through the ductus venosus.(Am J Obstet Gynecol 1997;177:90)

      Keywords

      To read this article in full you will need to make a payment

      Purchase one-time access:

      Academic & Personal: 24 hour online accessCorporate R&D Professionals: 24 hour online access
      One-time access price info
      • For academic or personal research use, select 'Academic and Personal'
      • For corporate R&D use, select 'Corporate R&D Professionals'

      Subscribe:

      Subscribe to American Journal of Obstetrics & Gynecology
      Already a print subscriber? Claim online access
      Already an online subscriber? Sign in
      Institutional Access: Sign in to ScienceDirect

      References

        • Kiserud T
        • Eik-Nes SH
        • Blaas H-G
        • Hellevik LR.
        Ultrasonographic velocimetry of the fetal ductus venosus.
        Lancet. 1991; 338: 1412-1414
        • Huisman TWA
        • Stewart PA
        • Wladimiroff JW.
        Ductus venosus blood flow velocity waveforms in the human fetus—a Doppler study.
        Ultrasound Med Biol. 1992; 18: 33-37
        • Kiserud T
        • Eik-Nes SH
        • Hellevik LR
        • Blaas H-G.
        Ductus venosus blood velocity changes in fetal cardiac diseases.
        J Matern Fetal Invest. 1993; 3: 15-20
        • DeVore GR
        • Horenstein J.
        Ductus venosus index: a method for evaluating right ventricular preload in the second-trimester fetus.
        Ultrasound Obstet Gynecol. 1993; 3: 338-342
        • Kiserud T
        • Eik-Nes SH
        • Blaas H-G
        • Hellevik LR
        • Simensen B.
        Ductus venosus blood velocity and the umbilical circulation in the seriously growth retarded fetus.
        Ultrasound Obstet Gynecol. 1994; 4: 109-114
        • Rizzo G
        • Capponi A
        • Arduini D
        • Romanini C.
        Ductus venosus velocity waveforms in appropriate and small for gestational age fetuses.
        Early Hum Dev. 1994; 39: 15-26
        • Hecher K
        • Campbell S
        • Doyle P
        • Harrington K
        • Nicolaides K.
        Assessment of fetal compromise by Doppler ultrasound investigation of the fetal circulation.
        Circulation. 1995; 1995: 129-138
        • Oepkes D
        • Vandenbussche FP
        • van Bel F
        • Kanhai HHH.
        Fetal ductus venosus blood flow velocities before and after transfusion in red-cell alloimmunized pregnancies.
        Obstet Gynecol. 1993; 82: 237-241
        • Hecher K
        • Ville Y
        • Snijders R
        • Nicolaides K.
        Doppler studies of the fetal circulation in twin-twin transfusion syndrome.
        Ultrasound Obstet Gynecol. 1995; 5: 318-324
        • Kiserud T
        • Hellevik LR
        • Eik-Nes SH
        • Angelsen BAJ
        • Blaas H-G.
        Estimation of the pressure gradient across the fetal ductus venosus based on Doppler velocimetry.
        Ultrasound Med Biol. 1994; 20: 225-232
        • Emerson DS
        • Cartier MS
        • Felker RE
        • Altieri LA
        • Smith C
        • Moretti ML
        • et al.
        Increased shunting of umbilical venous blood via the ductus venosus in fetuses with IUGR: a Doppler study.
        J Ultrasound Med. 1991; 10 ([abstract]): S55
        • Rudolph AM
        • Heymann MA.
        Circulatory changes during growth in the fetal lamb.
        Circ Res. 1970; 26: 289-299
        • Behrman RE
        • Lees MH
        • Peterson EN
        • de Lannoy CW
        • Seeds AE.
        Distribution of the circulation in the normal and asphyxiated fetal primate.
        Am J Obstet Gynecol. 1970; 108: 956-969
        • Edelstone DI
        • Rudolph AM
        • Heymann MA.
        Liver and ductus venosus blood flows in fetal lambs in utero.
        Circ Res. 1978; 42: 426-433
        • Edelstone DI.
        Regulation of blood flow through the ductus venosus.
        J Dev Physiol. 1980; 2: 219-238
        • Itskovitz J
        • LaGamma EF
        • Rudolph AM.
        Effects of cord compression on fetal blood flow distribution and O2 delivery.
        Am J Physiol. 1987; 252: H100-H109
        • Rudolph AM.
        Distribution and regulation of blood flow in the fetal and neonatal lamb.
        Circ Res. 1985; 57: 811-821
        • Pearson AA
        • Sauter RW.
        The innervation of the umbilical vein in human embryos and fetuses.
        Am J Anat. 1969; 125: 345-352
        • Coceani F
        • Olley PM.
        The control of cardiovascular shunts in the fetal and perinatal period.
        Can J Pharmacol. 1988; 66: 1129-1134
        • Paulick RP
        • Meyers RL
        • Rudolph CD
        • Rudolph AM.
        Venous and hepatic vascular responses to indomethacin and prostaglandin E1 in the fetal lamb.
        Am J Obstet Gynecol. 1990; 163: 1357-1363
        • Paulick RP
        • Meyers RL
        • Rudolph CD
        • Rudolph AM.
        Umbilical and hepatic venous responses to circulating vasoconstrictive hormones in fetal lamb.
        Am J Physiol. 1991; 260: H1205-H1213
        • Paulick RP
        • Meyers RL
        • Rudolph CD.
        Venous responses to hypoxemia in the fetal lamb.
        J Dev Physiol. 1990; 14: 81-88
        • Weiner CP
        • Heilskov JRN
        • Pelzer GRN
        • Gram SRN.
        Normal values for human umbilical venous and amniotic fluid pressure and their alteration by fetal disease.
        Am J Obstet Gynecol. 1989; 161: 714-717
        • Ville Y
        • Sideris I
        • Hecher K
        • Snijders RJM
        • Nicolaides KH.
        Umbilical venous pressure in normal, growth-retarded, and anemic fetuses.
        Am J Obstet Gynecol. 1994; 170: 487-494
        • Jouppila P
        • Kirkinen P
        • Puukka R.
        Correlation between umbilical vein blood flow and umbilical blood viscosity in normal and complicated pregnancies.
        Arch Gynecol. 1986; 237: 191-197