Correlation between umbilical vein blood flow and umbilical blood viscosity in normal and complicated pregnancies

1986 ◽  
Vol 237 (4) ◽  
pp. 191-197 ◽  
Author(s):  
P. Jouppila ◽  
P. Kirkinen ◽  
R. Puukka
Keyword(s):  
Blood Flow ◽  
Blood Viscosity ◽  
Umbilical Vein ◽  
Umbilical Blood

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.

Fetal O2 consumption in sheep during controlled long-term reductions in umbilical blood flow

1986 ◽  
Vol 250 (6) ◽  
pp. H1037-H1042 ◽  
Author(s):  
D. F. Anderson ◽  
C. M. Parks ◽  
J. J. Faber
Keyword(s):  
Blood Flow ◽  
Polynomial Regression ◽  
Umbilical Vein ◽  
Control Period ◽  
Control Flow ◽  
Aortic Flow ◽  
O2 Consumption ◽  
Umbilical Blood ◽  
Umbilical Blood Flow

Electromagnetic flow sensors and inflatable occluders were placed on the distal aortas of nine fetal lambs of 111-124 days gestation; indwelling vascular catheters were placed in a lower body artery and vein and the common umbilical vein. After a control period of 7.6 +/- 2.1 (SD) days, distal aortic flow was reduced to about 60% of control flow; placental flow fractions of distal aortic flow were 77 +/- 5%, control; 69 +/- 11% during flow reduction. Duration of the flow reductions was 9.6 +/- 6.5 days. Fetal O2 consumption fell from 6.4 +/- 1.5 to 5.3 +/- 1.1 ml X min-1 X kg-1 (P less than 0.02) as umbilical blood flow was reduced from 202 +/- 47 to 116 +/- 36 ml X min-1 X kg-1 (P less than 0.001). Least-squares polynomial regression analysis showed that O2 consumption was a linear function of umbilical blood flow (P less than 0.01). With regard to long-term fetal O2 consumption, there was no evidence for a margin of safety in fetal umbilical blood flow.

Amino acid metabolism in the ovine fetus

1983 ◽  
Vol 244 (5) ◽  
pp. E459-E466 ◽  
Author(s):  
J. A. Lemons ◽  
R. L. Schreiner
Keyword(s):  
Amino Acids ◽  
Blood Flow ◽  
Umbilical Vein ◽  
Fetal Tissue ◽  
Maternal Circulation ◽  
Fed State ◽  
Arterial Circulation ◽  
Umbilical Blood ◽  
Ovine Fetus ◽  
Branched Chain

Quantitative measurements of the umbilical uptake of a variety of substrates were made in the ovine fetus in both the fed state and after 5 days of maternal fasting. Blood flow was measured in both study periods using the antipyrine method, with the simultaneous measurement of umbilical vein and arterial concentrations of glucose, oxygen, and 25 amino acids in whole blood. Umbilical blood flow and fetal oxygen consumption remained unchanged between the fed and fasted states. Umbilical glucose uptake decreased from a mean of 6.85 to 2.79 mg X kg-1 X min-1 with a concomitant fall in the glucose:oxygen quotient from a mean of 0.70 to 0.31. Whereas the majority of gluconeogenic amino acids decreased in concentration in the maternal circulation during fasting, the branched-chain amino acids, as well as 3-methylhistidine, increased. In contrast the majority of amino acids in the fetal arterial circulation either increased significantly or remained unchanged in concentration. Although the fetal excretion of urea increased by 70% during the period of maternal fasting, the total fetal uptake of nitrogen in the form of free amino acids via the umbilical circulation did not change (1,337 vs. 1,027 mg X kg-1 X day-1). These data suggest that the supply of amino acids from the mother to the fetus does not change dramatically during maternal fasting. Therefore, the fetus must either catabolize amino acids previously destined for fetal tissue synthesis and/or begin catabolizing its own protein stores.

Absence of fetal placental waterfall phenomenon in chronically prepared fetal lambs

1976 ◽  
Vol 230 (4) ◽  
pp. 886-892 ◽  
Author(s):  
KL Thornburg ◽  
JM Bissonnette ◽  
JJ Faber
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Arterial Blood Pressure ◽  
Umbilical Vein ◽  
Venous Pressure ◽  
Amniotic Cavity ◽  
Umbilical Blood ◽  
Arterial Blood ◽  
Placental Blood ◽  
Umbilical Blood Flow

An electromagnetic flow sensor was placed on the distal fetal aorta (umbilical flow fraction 78.1 +/- 1.6 SEM, %), an inflatable occluder was tied around the umbilical cord, and catheters were placed in distal branches of an umbilical artery and vein, a uterine vein, and in the amniotic cavity. An inflatalbe occluder was tied around the vagina of some of the ewes. Control values 3 days after surgery were (mean +/- SE): fetal femoral artery pH, 7.37 +/- 0.01; umbilical blood flow, 186 +/- 14 ml-min-1 .kg fetus-1; fetal arterial blood pressure, 39 +/- 3 mmHg; and umbilical venous pressure, 7.4 +/- 1.0 mmHg (above intrauterine pressure). Fetal weight at autopsy was 3.1 +/- 0.3 kg, n = 11. Small increases in umbilical vein pressure caused immediate decreases in placental blood flow without decreases in fetal arterial blood pressure. The relation between venous pressure and umbilical blood flow at constant arterial pressure was that of an inert system, i.e., no evidence of a surrounding pressure (Starling resistor effect or waterfall phenomenon) could be found with increases in venous pressures of 2-40 mmHg. The results were not affected by increases in uterine vein pressure between 2 and 30 mmHg, nor by anesthesia and supine position of the ewe, nor by ganglionic blockade of the fetal ANS. It was concluded that surrounding pressures in the fetal placental circulation could not be demonstrated.

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.

scholarly journals Quantitative Monitoring of Dynamic Blood Flows Using Coflowing Laminar Streams in a Sensorless Approach

2021 ◽  
Vol 11 (16) ◽  
pp. 7260
Author(s):  
Yang Jun Kang
Keyword(s):  
Blood Flow ◽  
Flow Rate ◽  
Blood Viscosity ◽  
Measurement Errors ◽  
Present Method ◽  
Test Fluid ◽  
Constant Flow Rate ◽  
Rbc Aggregation ◽  
Sinusoidal Flow ◽  
Analytical Expressions

Determination of blood viscosity requires consistent measurement of blood flow rates, which leads to measurement errors and presents several issues when there are continuous changes in hematocrit changes. Instead of blood viscosity, a coflowing channel as a pressure sensor is adopted to quantify the dynamic flow of blood. Information on blood (i.e., hematocrit, flow rate, and viscosity) is not provided in advance. Using a discrete circuit model for the coflowing streams, the analytical expressions for four properties (i.e., pressure, shear stress, and two types of work) are then derived to quantify the flow of the test fluid. The analytical expressions are validated through numerical simulations. To demonstrate the method, the four properties are obtained using the present method by varying the flow patterns (i.e., constant flow rate or sinusoidal flow rate) as well as test fluids (i.e., glycerin solutions and blood). Thereafter, the present method is applied to quantify the dynamic flows of RBC aggregation-enhanced blood with a peristaltic pump, where any information regarding the blood is not specific. The experimental results indicate that the present method can quantify dynamic blood flow consistently, where hematocrit changes continuously over time.

Placental transfer as a function of uterine blood flow

1982 ◽  
Vol 242 (3) ◽  
pp. H429-H436 ◽  
Author(s):  
R. B. Wilkening ◽  
S. Anderson ◽  
L. Martensson ◽  
G. Meschia
Keyword(s):  
Blood Flow ◽  
Placental Transfer ◽  
Appreciable Effect ◽  
Uterine Blood Flow ◽  
Placental Perfusion ◽  
Umbilical Blood ◽  
Norepinephrine Infusion ◽  
Umbilical Blood Flow ◽  
Clearance Level ◽  
Different Levels

The effect of variations of uterine blood flow (F) on placental transfer was examined in six chronic sheep preparations by measuring the placental clearances of ethanol (CE) and antipyrine (CA) at different levels of F. Norepinephrine infusion, hemorrhage, and occlusion of the terminal aorta were used to reduce F below normal. The reduction of F had no appreciable effect on umbilical blood flow (f). In each ewe, CE significantly correlated with F. The CE vs. F relationship at constant f was curvilinear with convexity toward the clearance axis. Regression analysis showed that the equation 1/CE = 1/.911 F + 1/.831 f could account for most of the CE variance (r2 = 0.97). Implicit in this relation is the concept that, given a certain level of placental perfusion, an F/f ratio congruent to 1 is optimal for the exchange of highly diffusible inert molecules between mother and fetus [CE/(F + f) was maximum at F/f = 0.955]. CA was not significantly different from CE at low clearance level but became smaller than CE at clearance values greater than 300 ml/min. This suggests that a high rates of perfusion placental permeability was a factor in limiting CA.

scholarly journals Necrotizing funisitis and calcification of umbilical vein: case report and review

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Wendi Wang ◽  
Miao Zhang ◽  
Liyun Gong ◽  
Qingqing Wu
Keyword(s):  
Umbilical Cord ◽  
Umbilical Vein ◽  
Supportive Therapy ◽  
Vascular Wall ◽  
Adverse Outcomes ◽  
Prenatal Ultrasonography ◽  
Severe Inflammation ◽  
Umbilical Blood ◽  
Emergency Cesarean ◽  
Wall Calcification

Abstract Background Necrotising funisitis (NF) is a rare, chronic stage of funisitis, a severe inflammation of the umbilical cord and an important risk factor for fetal adverse outcomes. NF is characterized by yellow-white bands running parallel to the umbilical blood vessels. These bands consist of inflammatory cells, necrotic debris, and calcium deposits. Calcification is visible in ultrasonography, which makes it possible to suspect NF when umbilical vascular wall calcification is detected by prenatal ultrasonography. Case presentation Ultrasonography revealed calcification of the umbilical venous wall in an expectant 31-year-old woman who was gravida 1, para 0. The woman required emergency cesarean section because of fetal distress and suspected umbilical cord torsion at 31 weeks gestation. The root of the umbilical cord was quite fragile and broke during the operation. The pathological results on the placenta showed histologic chorioamnionitis and NF. The infant was diagnosed to have neonatal sepsis and acidosis after delivery but was discharged without severe complications after a one-month hospitalization that included antibiotic and supportive therapy. Conclusion NF is a rare and severe inflammation of the umbilical cord. Umbilical vascular wall calcification discovered in prenatal ultrasonography is diagnostically helpful.

scholarly journals CSH RNA Interference Reduces Global Nutrient Uptake and Umbilical Blood Flow Resulting in Intrauterine Growth Restriction

2021 ◽  
Vol 22 (15) ◽  
pp. 8150
Author(s):  
Amelia R. Tanner ◽  
Cameron S. Lynch ◽  
Victoria C. Kennedy ◽  
Asghar Ali ◽  
Quinton A. Winger ◽  
...  
Keyword(s):  
Blood Flow ◽  
Rna Interference ◽  
Nutrient Uptake ◽  
Intrauterine Growth Restriction ◽  
Growth Restriction ◽  
Intrauterine Growth ◽  
Umbilical Blood ◽  
Uterine Growth ◽  
Umbilical Blood Flow ◽  
Placental Hormone

Deficiency of the placental hormone chorionic somatomammotropin (CSH) can lead to the development of intrauterine growth restriction (IUGR). To gain insight into the physiological consequences of CSH RNA interference (RNAi), the trophectoderm of hatched blastocysts (nine days of gestational age; dGA) was infected with a lentivirus expressing either a scrambled control or CSH-specific shRNA, prior to transfer into synchronized recipient sheep. At 90 dGA, umbilical hemodynamics and fetal measurements were assessed by Doppler ultrasonography. At 120 dGA, pregnancies were fitted with vascular catheters to undergo steady-state metabolic studies with the 3H2O transplacental diffusion technique at 130 dGA. Nutrient uptake rates were determined and tissues were subsequently harvested at necropsy. CSH RNAi reduced (p ≤ 0.05) both fetal and uterine weights as well as umbilical blood flow (mL/min). This ultimately resulted in reduced (p ≤ 0.01) umbilical IGF1 concentrations, as well as reduced umbilical nutrient uptakes (p ≤ 0.05) in CSH RNAi pregnancies. CSH RNAi also reduced (p ≤ 0.05) uterine nutrient uptakes as well as uteroplacental glucose utilization. These data suggest that CSH is necessary to facilitate adequate blood flow for the uptake of oxygen, oxidative substrates, and hormones essential to support fetal and uterine growth.

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