Assessment of umbilical arterial and venous flow using color Doppler

Lees, C.; Albaigés, G.; Deane, Colin; Parra, M.; Nicolaides, Kypros H.

doi:10.1046/j.1469-0705.1999.14040250.x

Cited by 70 publications

(86 citation statements)

References 19 publications

(23 reference statements)

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“…Normally, fetal blood flow into the placenta during the third trimester is at a rate of Q N ϭ 500 ml/min. Accordingly, if the umbilical arteries are identical, the averaged flow rate through each is 250 ml/min (11). Hence, for the normal symmetric case, we assumed that the flow into each artery is Q 1 ϭ Q2 ϭ 250 ml/min.…”

Section: Methodsmentioning

confidence: 99%

Hemodynamic analysis of Hyrtl anastomosis in human placenta

Gordon¹,

Eytan²,

Jaffa³

et al. 2007

American Journal of Physiology-Regulatory, Integrative and Comp

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The Hyrtl anastomosis is a common connection between the umbilical arteries near the cord insertion in most human placentas. It has been speculated that it equalizes the blood pressure between the territories supplied by the umbilical arteries. However, its functional role in the regulation and distribution of fetal blood flow to the placenta has not yet been explored. A computational model has been developed for quantitative analysis of hemodynamic characteristic of the Hyrtl anastomosis in cases of discordant blood flow in the umbilical arteries. Simulations were performed for cases of either increased placental resistance at the downstream end or reduced arterial blood flow due to some pathologies upstream of one of the arteries. The results indicate that when placental territories of one artery impose increased resistance to fetal blood flow, the Hyrtl anastomosis redistributes the blood flow into the second artery to reduce the large pressure gradients that are developed in the affected artery. When one of the arteries conducts a smaller blood flow into the placenta and a relatively smaller pressure gradient is developed, the Hyrtl anastomosis rebuilds the pressure gradients in the affected artery and redistributes blood flow from the unaffected artery to the affected one to improve placental perfusion. In conclusion, the Hyrtl anastomosis plays the role of either a safety valve or a pressure stabilizer between the umbilical arteries at the placental insertion.

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Section: Methodsmentioning

confidence: 99%

Hemodynamic analysis of Hyrtl anastomosis in human placenta

Gordon¹,

Eytan²,

Jaffa³

et al. 2007

American Journal of Physiology-Regulatory, Integrative and Comp

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“…The inter-and intra-observer variability of the umbilical artery PI using Doppler has been described previously [7]. Worsening fetal hypoxia is indicated by a rise in umbilical artery resistance which is indicated by an increase in PI.…”

Section: Methodsmentioning

confidence: 99%

Neonatal Coagulopathy in Preterm, Small-for-Gestational-Age Infants

Hannam¹,

Lees

Edwards

et al. 2003

Neonatology

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Our aim was to determine if antenatal hypoxia was associated with liver dysfunction and coagulation abnormalities in small-for-gestational-age (SGA) infants. Sixteen SGA infants, median gestational age 30 (range 26–32) weeks, who consecutively had had umbilical artery Doppler studies in the week before delivery, were compared to appropriate-for-gestational-age (AGA) controls, who were each matched to an SGA infant for gestational age. The median international normalised ratio (INR) was significantly higher (1.9 vs. 1.3, p < 0.001) and the neutrophil (p = 0.003) and platelet counts (p < 0.001), alkaline phosphatase (p < 0.001) and albumin (p < 0.02) levels significantly lower in the SGA compared to the AGA group. The umbilical artery pulsatility index (PI) was elevated, indicating antenatal hypoxia, in all but 1 of the SGA infants. Multiple linear regression analysis demonstrated that the INR was significantly related to the umbilical artery PI independent of the other variables (p = 0.0002, R² = 0.71). These results suggest that the coagulopathy seen in preterm SGA infants might at least be partially explained by antenatal hypoxia affecting the liver and hence vitamin K-dependent coagulation.

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“…Several studies show that there is a significant increase in umbilical arterial flow (u a1 and u a2 ) from 112.66 ± 58.32 ml/min at 23 weeks to 256.46 ± 58.9 ml/min at 33 weeks (r = 0.66, p < 0.001) and umbilical vein flow (u v ) from 95.04 ± 64.8 ml/ min at 23 weeks to 303.28 ± 63.8 ml/min at 33 weeks (r = 0.76, p < 0.001) [42]. At term, maternal blood flow to the placenta is approximately 600-700 ml/min [43].…”

Section: A Effect Of Gestational Age On Simulationmentioning

confidence: 95%

Simulation and Analysis of Umbilical Blood Flow using Markov-based Mathematical Model

Queyam¹,

Pahuja²,

Singh³

2017

IJISA

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Abstract-The intra-uterine development of the fetus depends on various factors, one such critical factor is umbilical blood flow because the quantity of oxygen delivered to the placenta and to the fetus is directly limited by umbilical blood flow rate. Since the measurement of the hemodynamic quantities such as blood pressure and blood flow rate is not possible in utero hence the use of patient-specific mathematical modeling is beneficial for the assessment of feto-maternal wellbeing. A Markov model based mathematical model of fetal circulation is developed by taking three node concept. The fetus, the umbilical cord, and the placenta represent the 3 nodes of Markov model. A LabVIEWbased virtual instrument is designed to simulate the mathematical model which results in waveform similar to Doppler blood flow velocimetry of umbilical artery. The model is simulated at various degree of conductivity of the umbilical cord to the oxygenated blood. Simulation results show that the umbilical artery blood flow velocity waveform depends on gestation age, fetal heart rate, uterine contraction and placental insufficiency. The Doppler indices calculated from simulation helps in predicting both fetal and maternal abnormalities at various degrees of the conductivity to the blood flow passage. Therefore, integrating patient-specific models along with established medical equipments will be helpful in identifying true intra-uterine growth restricted fetuses from normal fetuses and helps clinicians to take timely interventions.

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Assessment of umbilical arterial and venous flow using color Doppler

Abstract: ABSTRACT

Cited by 70 publications

References 19 publications

Hemodynamic analysis of Hyrtl anastomosis in human placenta

Hemodynamic analysis of Hyrtl anastomosis in human placenta

Neonatal Coagulopathy in Preterm, Small-for-Gestational-Age Infants

Simulation and Analysis of Umbilical Blood Flow using Markov-based Mathematical Model

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