Uterine blood flow and oxygen consumption in pregnant sheep and goats

1959 ◽  
Vol 197 (4) ◽  
pp. 929-934 ◽  
Author(s):  
James Metcalfe ◽  
Seymour L. Romney ◽  
Joseph R. Swartwout ◽  
Donald M. Pitcairn ◽  
Anton N. Lethin ◽  
...  
Keyword(s):  
Blood Flow ◽  
Nitrous Oxide ◽  
Oxygen Consumption ◽  
Maternal Blood ◽  
Uterine Blood Flow ◽  
Human Beings ◽  
Pregnant Uterus ◽  
Fick Principle ◽  
Pregnant Sheep ◽  
Made In

This report deals with the volume of maternal blood flow to the pregnant uterus of the sheep and goat. Studies were made in 2 nonpregnant animals and in 20 pregnant animals at known stages of gestation. Measurements of uterine blood flow were made using nitrous oxide according to the Fick principle. The results indicate that in the nonpregnant uterus the blood flow is approximately 25 ml/min. It increases to approximately 200 ml/min. at the 80th day of gestation and exceeds 1000 ml/min. near the end of the 150-day gestation period of these animals. Data are also included for calculation of uterine O2 consumption. The findings with regard to uterine blood flow and O2 consumption are discussed in relation to previous findings in human beings and in rabbits.

Exercise responses in pregnant sheep: oxygen consumption, uterine blood flow, and blood volume

1983 ◽  
Vol 55 (3) ◽  
pp. 834-841 ◽  
Author(s):  
F. K. Lotgering ◽  
R. D. Gilbert ◽  
L. D. Longo
Keyword(s):  
Blood Flow ◽  
Oxygen Consumption ◽  
Blood Volume ◽  
Maximal Oxygen Consumption ◽  
Maternal Blood ◽  
Uterine Blood Flow ◽  
Pregnant Sheep ◽  
Exercise Period ◽  
Maternal Exercise ◽  
Maternal Responses

In an attempt to explore the acute maternal responses to exercise we measured oxygen consumption, uterine blood flow, and blood volume in 13 chronically catheterized pregnant sheep at rest and while exercising on a treadmill. With maximal exercise O2 consumption increased 5.6 times, from a resting value of 5.8 +/- 0.3 (SE) to 32.1 +/- 2.8 ml X min -1 X kg -1, cardiac output increased 2.7 times, from 149 +/- 8 to 404 +/- 32 ml X min -1 X kg -1, and arteriovenous oxygen content difference increased 2.1 times, from 3.9 +/- 0.2 to 8.0 +/- 0.4 ml X dl -1. Total uterine blood flow decreased from a mean resting value of 292 +/- 6 to 222 +/- 19 ml X min -1 X kg fetus -1 near exhaustion during prolonged (40 min) exercise at 70% maximal oxygen consumption. Maternal blood volume decreased 14% (P less than 0.01) from 67.5 +/- 3.7 to 57.8 +/- 3.6 ml X kg -1 during this exercise period, with a 20% decrease in plasma volume without a change in red cell volume. We conclude that uterine blood flow decreases during maternal exercise. However, hemoconcentration helps to maintain a relatively constant oxygen delivery to the uterus.

Maternal-fetal glucose exchange: necessity of a three-pool model

1984 ◽  
Vol 246 (6) ◽  
pp. E528-E534 ◽  
Author(s):  
W. W. Hay ◽  
J. W. Sparks ◽  
F. C. Battaglia ◽  
G. Meschia
Keyword(s):  
Glucose Utilization ◽  
Maternal Blood ◽  
Fetal Blood ◽  
Entry And Exit ◽  
Tissue Mass ◽  
Pregnant Uterus ◽  
Fick Principle ◽  
Pregnant Sheep ◽  
Pool Model ◽  
Net Flux

Tracer glucose was infused simultaneously into mother ( [6-3H]glucose) and fetus ( [U-14C]glucose) in pregnant sheep in the last month of gestation to study the exchange of glucose molecules between maternal and fetal blood. Net rates of entry and exit of tracer glucose via the uterine and umbilical circulations were measured by application of the Fick principle under steady-state conditions. The net flux of fetal tracer to the uteroplacenta from the fetus was 53.4 +/- 3.1% of the fetal tracer infusion. The net flux of fetal tracer into maternal blood was 43.8 +/- 5.0% of the net flux of fetal tracer to the uteroplacenta from fetal blood. The net flux of maternal tracer to the uterus from the mother was 31.7 +/- 2.8% of the maternal tracer infusion. The net flux of maternal tracer into fetal blood was 40.5 +/- 4.4% of the net flux to pregnant uterus from maternal blood. This evidence demonstrates that the uteroplacental tissue mass constitutes a glucose pool that is interposed between the maternal and fetal glucose pools and rapidly metabolizes glucose molecules derived from both maternal and fetal blood. Calculations based on a three-pool model show that the fetal glucose pool contributes approximately 40% of the glucose that is metabolized by the placenta. The comparison of the three-pool model with a previously proposed two-pool reversible model shows that the latter lumps the placental utilization of fetal glucose with fetal glucose utilization and overestimates the rate of fetal glucose metabolism by approximately 60%.

Regional blood flow and vascular resistance in response to oxytocin in the pregnant sheep and dog

1961 ◽  
Vol 16 (6) ◽  
pp. 1087-1092 ◽  
Author(s):  
N. S. Assali ◽  
L. Holm ◽  
H. Parker
Keyword(s):  
Blood Flow ◽  
Vascular Resistance ◽  
Regional Blood Flow ◽  
Uterine Blood Flow ◽  
Pregnant Uterus ◽  
Blood Flows ◽  
Uterine Contractions ◽  
Intravenous Drip ◽  
Pregnant Sheep ◽  
Regional Vascular Resistance

The effects of oxytocin on regional blood flow and regional vascular resistance were investigated in a group of pregnant ewes and bitches not in labor and in another group in early labor. Single injections or intravenous drip infusion did not change significantly arterial pressure, cardiac output, electrocardiogram, and renal, iliac, femoral, and carotid blood flows in any of the animals studied. The effects on the pregnant uterus were negligible before the onset of spontaneous labor. Only when the animal was in labor did oxytocin produce an increase in uterine contractions accompanied by a significant decrease in uterine blood flow. The data indicate that in the pregnant sheep and dog the circulatory action of oxytocin is limited to the pregnant uterus in labor and that the decrease in blood flow is probably due to an increase in intramural vascular resistance caused by the contracting myometrium around the uterine arterioles. Submitted on May 5, 1961

Blood flow and oxygen consumption of the pregnant uterus

1961 ◽  
Vol 200 (2) ◽  
pp. 274-278 ◽  
Author(s):  
William E. Huckabee ◽  
James Metcalfe ◽  
Harry Prystowsky ◽  
Donald H. Barron
Keyword(s):  
Blood Flow ◽  
Oxygen Consumption ◽  
Early Pregnancy ◽  
Uterine Blood Flow ◽  
Pregnant Uterus ◽  
Gestational Period

The 4-aminoantipyrine method was employed for measuring rate of blood flow per kilogram of tissue in the pregnant uterus of anesthetized goats. A uterine vein was cannulated, but no other manipulation or disturbance of the uterus occurred. Uterine blood flow was high in the nonpregnant uterus and in early pregnancy but fell to a plateau of 277 ml/kg/min. at midpregnancy. (A-V)O2 was minimal in the first quarter of pregnancy and rose to a plateau also by midpregnancy. Rate of O2 consumption per kilogram was relatively high in the nonpregnant uterus, fell to a minimal value in the first quarter of the gestational period, and rose again to a plateau of 10.1 ml/kg/ min. beginning at midpregnancy. All these values appeared to remain unchanged during the last half of gestation.

O2 delivery to the pregnant uterus: its relationship to O2 consumption

1979 ◽  
Vol 237 (1) ◽  
pp. R52-R57
Author(s):  
D. Caton ◽  
C. Crenshaw ◽  
C. J. Wilcox ◽  
D. H. Barron
Keyword(s):  
Blood Flow ◽  
Relative Magnitude ◽  
O2 Consumption ◽  
Uterine Blood Flow ◽  
Pregnant Uterus ◽  
Content Difference ◽  
Several Variables ◽  
Pregnant Sheep ◽  
Systematic Relationships ◽  
O2 Delivery

Normal sheep were studied at intervals of 3-5 days during the last weeks of pregnancy in order to evaluate variability in rate of O2 consumption (QO2) of the uterus in relation to several variables involved in delivery of O2 to the organ. Among-animal differences of uterine QO2 were statistically significant and directly related to birthweight of the lamb. Among-animal differences of uterine blood flow (UBF) and uterine arteriovenous O2 content difference [C(a-v)O2] also were statistically significant, though neither was related to birthweight, presumably since they tended to vary inversely with one another. In a given ewe relative magnitude of UBF and of C(a-v)O2 was related to maternal arterial O2 content (CaO2), day of pregnancy, and whether the animal carried singlets or twins. Variability in QO2 was most closely related to UBF, although its relations to C(a-v)O2 and CaO2 were significant also. These data suggest there are systematic relationships among variables involved in the delivery of O2 to the uterus of pregnant sheep.

Behavioral activity during prolonged hypoxemia in fetal sheep

1988 ◽  
Vol 65 (6) ◽  
pp. 2420-2426 ◽  
Author(s):  
A. D. Bocking ◽  
R. Gagnon ◽  
K. M. Milne ◽  
S. E. White
Keyword(s):  
Blood Flow ◽  
Eye Movements ◽  
Normal Incidence ◽  
Behavioral Activity ◽  
Uterine Blood Flow ◽  
Fetal Sheep ◽  
Pregnant Sheep ◽  
Fetal Breathing ◽  
Fetal Breathing Movements ◽  
Internal Iliac

Experiments were conducted in unanesthetized, chronically catheterized pregnant sheep to determine the fetal behavioral response to prolonged hypoxemia produced by restricting uterine blood flow. Uterine blood flow was reduced by adjusting a vascular occluder placed around the maternal common internal iliac artery to decrease fetal arterial O2 content from 6.1 +/- 0.3 to 4.1 +/- 0.3 ml/dl for 48 h. Associated with the decrease in fetal O2 content, there was a slight increase in fetal arterial PCO2 and decrease in pH, which were both transient. There was an initial inhibition of both fetal breathing movements and eye movements but no change in the pattern of electrocortical activity. After this initial inhibition there was a return to normal incidence of both fetal breathing movements and eye movements by 16 h of the prolonged hypoxemia. These studies indicate that the chronically catheterized sheep fetus is able to adapt behaviorally to a prolonged decrease in arterial O2 content secondary to the restriction of uterine blood flow.

The Effects of S(+)-Ketamine and Racemic Ketamine on Uterine Blood Flow in Chronically Instrumented Pregnant Sheep

2004 ◽  
pp. 497-502 ◽  
Author(s):  
Danja Str??mper ◽  
Wiebke Gogarten ◽  
Marcel E. Durieux ◽  
Kristian Hartleb ◽  
Hugo Van Aken ◽  
...  
Keyword(s):  
Blood Flow ◽  
Uterine Blood Flow ◽  
Pregnant Sheep ◽  
Racemic Ketamine

Effects of hyperthermia on uterine blood flow and shunting through uterine arteriovenous anastomoses in the late-pregnant ewe

1999 ◽  
Vol 11 (5) ◽  
pp. 201 ◽  
Author(s):  
Suzanne L. Miller ◽  
Graham Jenkin ◽  
David W. Walker
Keyword(s):  
Blood Flow ◽  
Experimental Period ◽  
Respiratory Alkalosis ◽  
Uterine Horn ◽  
Arteriovenous Anastomoses ◽  
Uterine Blood Flow ◽  
Ambient Conditions ◽  
Total Blood ◽  
Uterine Arteries ◽  
Pregnant Sheep

The effect of maternal hyperthermia on uterine blood flow (UBF) through the two main uterine arteries and on the proportion of UBF shunted through uterine arteriovenous anastomoses (AVAs) was investigated. Eight late-pregnant ewes were exposed to normothermic (22–23˚C) or hyperthermic (approx-imately 39˚C) ambient conditions for 8 h. UBF was measured in the left and right uterine arteries using flow probes and microspheres were injected into the uterine artery before, during and after the experimental period. The distribution of microspheres between the uterus and lungs was determined to calculate changes in capillary and AVA blood flows. Hyperthermia produced a significant (P<0.05) increase in maternal core temperature (+1.5˚C), increase in maternal blood pH (+0.21; P<0.05) and decrease in maternal pCO 2 (–16.2 mmHg; P<0.05). Blood flow to the uterine horn ipsilateral to the corpus luteum (CL) remained unchanged during hyperthermia, whereas total UBF and blood flow to the contralateral uterine horn were significantly decreased (P<0.05), by 23.1% and 20.8%, respectively, of pre-heat control values. The proportion of UBF shunted through uterine AVAs during hyperthermia was not significantly different from values observed in normothermic ewes (21.9 0.7%). Mild to moderate hyperthermia in late-pregnant sheep induces respiratory alkalosis and decreases total blood flow to the uterus, brought about by a decrease in blood flow to the uterine horn contralateral, but not ipsilateral to the CL. Heat treatment does not alter the proportion of UBF traversing uterine AVAs.

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