Effect of occluding one umbilical artery on placental oxygen transport

1991 ◽  
Vol 260 (4) ◽  
pp. H1319-H1325
Author(s):  
R. B. Wilkening ◽  
G. Meschia
Keyword(s):  
Blood Flow ◽  
Umbilical Artery ◽  
Umbilical Vein ◽  
Venous Blood ◽  
Diffusion Method ◽  
Limiting Factor ◽  
Fetal Blood ◽  
Umbilical Blood ◽  
O2 Transport ◽  
Acute Changes

Placental O2 transport was studied in seven fetal lambs before and after occluding one of the two umbilical arteries. Ethanol was used to measure uterine and umbilical blood flows using the steady-state transplacental diffusion method. Blood samples were drawn from umbilical artery, umbilical vein, both uterine veins, and maternal artery and analyzed for blood flow indicator, O2 content, PO2, PCO2, and pH. Occlusion reduced the placental mass and the uterine blood flow, which was available for transplacental exchange, to 49.5 and 46.5% of control, respectively. After occlusion, fetal blood pressure increased 38%, total umbilical blood flow decreased 25%, total fetal O2 uptake decreased 26%, fetal blood flow to the unoccluded placenta increased 52%, and the O2 flux from unoccluded placenta to fetus increased 49%. This increased flux was accompanied by a decrease in the PO2 of maternal venous blood from the unoccluded placenta and an enlargement of the transplacental PO2 gradient, resulting in a marked drop in umbilical venous PO2 (28.3 to 17.7 Torr). This evidence supports the hypothesis that placental O2 diffusing capacity is a limiting factor in placental O2 transport and agrees with other studies indicating the absence of homeostatic mechanisms for preventing acute changes of PO2 in the placental circulation.

Hemodynamic model for analysis of Doppler ultrasound indexes of umbilical blood flow

1999 ◽  
Vol 276 (6) ◽  
pp. H2204-H2214 ◽  
Author(s):  
Ayala Kleiner-Assaf ◽  
Ariel J. Jaffa ◽  
David Elad
Keyword(s):  
Blood Flow ◽  
Flow Rate ◽  
Umbilical Artery ◽  
Blood Flow Rate ◽  
Velocity Profiles ◽  
Fetal Blood ◽  
System Parameters ◽  
Umbilical Blood ◽  
Hemodynamic Model ◽  
Umbilical Blood Flow

A hemodynamic model for pulsatile fluid flow in a pressurized thin-walled elastic tube was applied for the computation of volumetric blood flow and velocity profiles for a given set of system parameters at any selected location along the umbilical artery. The velocity profiles over one heart cycle provide the fetal blood flow velocity waveforms (FVW) from which the usual Doppler indexes (DI) can be derived. The model was used for a comprehensive investigation of the correlation between DI and system parameters that reflect the anatomy and physiology of umbilical blood flow. The simulations showed that the radial location of the Doppler measurement is insignificant for the calculated DI, whereas the axial site is important. The analysis showed that decreasing the diameter or increasing the length of the umbilical artery reduces fetal mean blood flow rate and increases the DI. Increasing blood viscosity tends to induce similar patterns, whereas decreasing arterial compliance or increasing blood density decreases the DI with little effect on blood flow rate. Fetal heart rate has a minor effect on both DI and fetal blood flow rate. This study provides insight into the dependence of DI on the anatomic and physiological characteristics of umbilical blood flow.

scholarly journals Perinatal outcome of growth restricted fetus with absent end diastolic umbilical blood flow: Case report

2010 ◽  
Vol 63 (1-2) ◽  
pp. 123-126
Author(s):  
Marija Tasic ◽  
Vekoslav Lilic ◽  
Jelena Milosevic ◽  
Milan Stefanovic ◽  
Vladimir Antic
Keyword(s):  
Blood Flow ◽  
Case Report ◽  
Fetal Growth ◽  
Perinatal Outcome ◽  
Umbilical Artery ◽  
Fetal Monitoring ◽  
Elective Cesarean Section ◽  
Optimal Time ◽  
Biophysical Parameters ◽  
Umbilical Blood

Introduction. Absent or reversed end-diastolic blood flow in the umbilical artery is usually associated with poor perinatal outcome and high perinatal mortality rate. Case report. We present the case of a pregnant woman with absent end-diastolic blood flow in the umbilical artery in the 27th week of pregnancy with initial restriction of fetal growth. All though it was more and more obvious that the fetal growth was hindered, the Doppler, cardiotocographic and biophysical parameters did not get any worse as the pregnancy developed. The full fetal maturation was reached after the intense monitoring of the fetal condition and the pregnancy was terminated in the 37lh week by elective Cesarean section. Conclusion. The basic purpose of prenatal fetal monitoring in the situation of hindered fetal growth with chronic hypoxia is to predict the phase of decompensation and to terminate pregnancy before it is developed. The major problem is in great individual variations at the moment of development of decompensation phase, so the major obstetric aim in the monitoring of the fetus hindered in growth is to determine the optimal time and way of delivery.

scholarly journals The Effects of Epidural Analgesia during Labor on Maternal and Neonatal Outcomes

2020 ◽  
Author(s):  
Jin-Hua Huang ◽  
Mei Yu ◽  
Di-Bao Zhang ◽  
Jun-Ping Pan ◽  
Xiao-Tan Zhao ◽  
...  
Keyword(s):  
Epidural Analgesia ◽  
Apgar Score ◽  
Umbilical Artery ◽  
Umbilical Vein ◽  
Neonatal Outcomes ◽  
Epidural Group ◽  
Umbilical Blood ◽  
Vaginal Deliveries ◽  
Maternal And Neonatal Outcomes ◽  
The Impact

Abstract Background: The purpose of the study was to investigate the impact of epidural analgesia usage vs. non-epidural labor on maternal and neonatal outcomes. Methods: We included 129 parturients who had vaginal deliveries in our hospital since December 1, 2018. The women were grouped into the epidural analgesia group or the non-epidural group. In order to investigate the effect of epidural analgesia on mother and newborn outcomes, we evaluated the differences in labor duration, the Apgar score of the newborn, and the overall outcome of the mother and newborn. Results: Compared to the non-epidural group, the durations of the first and second stages of labor in the analgesia group were significantly longer. In terms of neonatal outcome, the epidural analgesia group had a higher lactate value in the umbilical artery blood and higher pCO2 of umbilical vein blood of the neonates. However, there were no significant differences in Apgar Score, umbilical blood pH, base excess, or other umbilical cord blood gas analyses (pO2, HGB, SO2, HCO3 -) between epidural analgesia and non-epidural labor groups.Conclusion: The epidural analgesia prolongs the duration of the first and second stages of labor and affects the level of lactate in umbilical artery blood and the partial pressure of carbon dioxide in umbilical vein blood. There was no significant effect on the basic characteristics of the mothers and neonates, suggesting that epidural analgesia delivery technology is safe, but it may have a particular short-term impact on neonatal outcomes.

Fetal neuromuscular blockade: effect on oxygen demand and placental transport

1989 ◽  
Vol 257 (3) ◽  
pp. H734-H738
Author(s):  
R. B. Wilkening ◽  
D. W. Boyle ◽  
G. Meschia
Keyword(s):  
Blood Flow ◽  
Oxygen Saturation ◽  
Neuromuscular Blockade ◽  
Umbilical Vein ◽  
Oxygen Demand ◽  
Arterial Oxygen ◽  
Uterine Blood Flow ◽  
Umbilical Blood ◽  
Steady State Method ◽  
Umbilical Blood Flow

To study mechanisms by which variations in fetal oxygen demand alter fetal oxygen saturation and PO2, we measured uterine and umbilical blood flow and transplacental oxygen diffusion rate in eight chronically prepared pregnant ewes before and during fetal neuromuscular blockade with pancuronium bromide (0.2 mg/kg). Uterine and umbilical blood flows were measured by applying the steady-state method using ethanol as the test substance. Fetal oxygen uptake decreased 7.5% (P less than 0.05). Umbilical blood flow increased 6% (P less than 0.05), whereas uterine blood flow did not change significantly. Fetal arterial oxygen saturation increased markedly (54.8–60.9%; P less than 0.001). There were also significant increases in umbilical vein oxygen saturation (83.6–86.9%; P less than 0.01), uterine vein oxygen saturation (70.7–72.2%; P less than 0.01), umbilical vein PO2 (29.4–32.1 Torr; P less than 0.001), and uterine vein PO2 (49.4–50.7 Torr; P less than 0.01). The uterine-umbilical venous PO2 difference decreased significantly (20.0–18.6 Torr; P less than 0.001), whereas there was no significant change in the uterine-umbilical venous PCO2 difference or in the umbilical ethanol shunt. The data indicate that follows a small decrease in fetal oxygen demand is caused by two aspects of placental oxygen transport: 1) umbilical and uterine blood flow do not react homeostatically to prevent the rise of PO2 in the placental circulation, and 2) the decrease in oxygen flux from placenta to fetus is associated with a decrease in the transplacental PO2 gradient.

Umbilical Blood Flow and Glucose Uptake in Lamb Fetus Following Single Umbilical Artery Ligation

Neonatology ◽  
1975 ◽  
Vol 26 (3-4) ◽  
pp. 291-299 ◽  
Author(s):  
William Oh ◽  
Keiichiro Omori ◽  
Calvin J. Hobel ◽  
Allen Erenberg ◽  
George C. Emmanouilides
Keyword(s):  
Blood Flow ◽  
Glucose Uptake ◽  
Umbilical Artery ◽  
Single Umbilical Artery ◽  
Artery Ligation ◽  
Umbilical Blood ◽  
Umbilical Blood Flow

Antenatal fetal blood flow in the descending aorta and in the umbilical vein and their ratio in normal pregnancy

1988 ◽  
Vol 14 (4) ◽  
pp. 263-268 ◽  
Author(s):  
H.Y. Chen ◽  
F.M. Chang ◽  
H.C. Huang ◽  
F.J. Hsieh ◽  
C.C. Lu
Keyword(s):  
Blood Flow ◽  
Umbilical Vein ◽  
Normal Pregnancy ◽  
Fetal Blood ◽  
Descending Aorta
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