Amniotic Fluid Volume Responses to Amnio-Infusion of Amniotic Fluid Versus Lactated Ringer's Solution in Fetal Sheep

2004 ◽  
Vol 11 (6) ◽  
pp. 363-368 ◽  
Author(s):  
Robert A. Brace ◽  
Cecilia Y. Cheung
Keyword(s):  
Amniotic Fluid ◽  
Fluid Volume ◽  
Fetal Sheep ◽  
Ringer’S Solution ◽  
Amniotic Fluid Volume ◽  
Lactated Ringer's Solution

Amniotic fluid volume response to esophageal occlusion in fetal sheep

1991 ◽  
Vol 165 (6) ◽  
pp. 1620-1626 ◽  
Author(s):  
Yuji Fujino ◽  
Connie L. Agnew ◽  
Peter Schreyer ◽  
M. Gore Ervin ◽  
Dan J. Sherman ◽  
...  
Keyword(s):  
Amniotic Fluid ◽  
Fluid Volume ◽  
Fetal Sheep ◽  
Amniotic Fluid Volume ◽  
Volume Response

scholarly journals Inhibitor of intramembranous absorption in ovine amniotic fluid

2014 ◽  
Vol 306 (3) ◽  
pp. R185-R189 ◽  
Author(s):  
Robert A. Brace ◽  
Cecilia Y. Cheung ◽  
Debra F. Anderson
Keyword(s):  
Amniotic Fluid ◽  
Absorption Rate ◽  
Ringer Solution ◽  
Fluid Volume ◽  
Fetal Membrane ◽  
Fetal Sheep ◽  
Membrane Stretch ◽  
Amniotic Fluid Volume ◽  
Urine Production ◽  
Fetal Urine

Intramembranous absorption increases during intra-amniotic infusion of physiological saline solutions. The increase may be due partly to the concomitant elevation in fetal urine production as fetal urine contains a stimulator of intramembranous absorption. In this study, we hypothesized that the increase in intramembranous absorption during intra-amniotic infusion is due, in part, to dilution of a nonrenal inhibitor of intramembranous absorption that is present in amniotic fluid. In late-gestation fetal sheep, amniotic fluid volume and the four primary amniotic inflows and outflows were determined over 2-day intervals under three conditions: 1) control conditions when fetal urine entered the amniotic sac, 2) during intra-amniotic infusion of 2 l/day of lactated Ringer solution when urine entered the amniotic sac, and 3) during the same intra-amniotic infusion when fetal urine was continuously replaced with lactated Ringer solution. Amniotic fluid volume, fetal urine production, swallowed volume, and intramembranous absorption rate increased during the infusions independent of fetal urine entry into the amniotic sac or its replacement. Lung liquid secretion rate was unchanged during infusion. Because fetal membrane stretch has been shown not to be involved and because urine replacement did not alter the response, we conclude that the increase in intramembranous absorption that occurs during intra-amniotic infusions is due primarily to dilution of a nonrenal inhibitor of intramembranous absorption that is normally present in amniotic fluid. This result combined with our previous study suggests that a nonrenal inhibitor(s) together with a renal stimulator(s) interact to regulate intramembranous absorption rate and, hence, amniotic fluid volume.

scholarly journals Amniotic fluid volume responses to esophageal ligation in fetal sheep: contribution of lung liquid

2009 ◽  
Vol 200 (3) ◽  
pp. 313.e1-313.e6 ◽  
Author(s):  
Juanita K. Jellyman ◽  
Cecilia Y. Cheung ◽  
Robert A. Brace
Keyword(s):  
Amniotic Fluid ◽  
Fluid Volume ◽  
Fetal Sheep ◽  
Amniotic Fluid Volume ◽  
Lung Liquid

Renal and amniotic fluid responses to umbilicoplacental embolization for 20 days in fetal sheep

1997 ◽  
Vol 273 (3) ◽  
pp. R1094-R1102 ◽  
Author(s):  
M. L. Cock ◽  
R. Harding
Keyword(s):  
Amniotic Fluid ◽  
Fluid Volume ◽  
Partial Pressure Of Oxygen ◽  
Kidney Weight ◽  
Fetal Sheep ◽  
Amniotic Fluid Volume ◽  
Urine Production ◽  
Body Weights ◽  
Fetal Urine ◽  
And Control

We determined the effects of placental insufficiency induced by umbilicoplacental embolization on fetal renal function and amniotic fluid volume and composition. Pregnant ewes underwent surgery at 115 +/- 2 days after mating (term approximately 147 days) for implantation of fetal vascular, bladder, and amniotic sac catheters. We studied five fetuses from 120 to 140 days during umbilicoplacental embolization and six control fetuses. Umbilicoplacental embolization reduced fetal arterial partial pressure of oxygen from 24.1 +/- 0.5 mmHg (pretreatment) to 14.6 +/- 0.2 mmHg. Fetal body weights were reduced to 80% of control values. Urine production and glomerular filtration rate in treated fetuses were significantly lower than in controls at 135 days of gestation. Amniotic fluid volume was not different between embolized and control animals. Fetal urine production in treated fetuses, when adjusted for body weight, was not different from that in control fetuses. We conclude that, in fetal growth restriction, reduced kidney weight, rather than hypoxemia per se is responsible for reduced urine production, which, if severe and prolonged, may contribute to oligohydramnios.

scholarly journals Regulation of intramembranous absorption and amniotic fluid volume by constituents in fetal sheep urine

2013 ◽  
Vol 305 (5) ◽  
pp. R506-R511 ◽  
Author(s):  
Debra F. Anderson ◽  
Sonnet S. Jonker ◽  
Samantha Louey ◽  
Cecilia Y. Cheung ◽  
Robert A. Brace
Keyword(s):  
Amniotic Fluid ◽  
Ringer Solution ◽  
Fluid Volume ◽  
Late Gestation ◽  
Passive Component ◽  
Fetal Sheep ◽  
Amniotic Fluid Volume ◽  
Volume Absorption ◽  
Solute Fluxes ◽  
Fetal Urine

Our objective was to test the hypothesis that fetal urine contains a substance(s) that regulates amniotic fluid volume by altering the rate of intramembranous absorption of amniotic fluid. In late gestation ovine fetuses, amniotic fluid volumes, urine, and lung liquid production rates, swallowed volumes and intramembranous volume and solute absorption rates were measured over 2-day periods under control conditions and when urine was removed and continuously replaced at an equal rate with exogenous fluid. Intramembranous volume absorption rate decreased by 40% when urine was replaced with lactated Ringer solution or lactated Ringer solution diluted 50% with water. Amniotic fluid volume doubled under both conditions. Analysis of the intramembranous sodium and chloride fluxes suggests that the active but not passive component of intramembranous volume absorption was altered by urine replacement, whereas both active and passive components of solute fluxes were altered. We conclude that fetal urine contains an unidentified substance(s) that stimulates active intramembranous transport of amniotic fluid across the amnion into the underlying fetal vasculature and thereby functions as a regulator of amniotic fluid volume.

Decline in lung liquid volume and secretion rate during oligohydramnios in fetal sheep

1989 ◽  
Vol 67 (6) ◽  
pp. 2401-2407 ◽  
Author(s):  
K. A. Dickson ◽  
R. Harding
Keyword(s):  
Amniotic Fluid ◽  
Fetal Lung ◽  
Fluid Volume ◽  
Secretion Rate ◽  
Lung Hypoplasia ◽  
Liquid Volume ◽  
Fetal Sheep ◽  
Experimental Animals ◽  
Amniotic Fluid Volume ◽  
Lung Liquid

Reduced amniotic fluid volume often results in fetal lung hypoplasia. Our aim was to examine the effects of prolonged drainage of amniotic and allantoic fluids on lung liquid volume (Vl), secretion rate (Vs), and tracheal flow rate (Vtr) in fetal sheep. In five experimental animals, amniotic and allantoic fluids were drained from 107 to 135 days of gestation. The volume of fluid drained from the experimental animals was 411.8 +/- 24.4 ml/day (n = 140). In six control animals, amniotic fluid volume was 747.7 +/- 89.7 ml (n = 15). Wet and dry lung weights were 20-25% lower in experimental fetuses than in control fetuses. Fetal hemoglobin, O2 saturation, arterial PO2, pH, and hematocrit were unchanged by drainage. During the drainage period, Vl was up to 65% lower, Vs was up to 35% lower, and Vtr was up to 40% lower in experimental fetuses than in control fetuses. We conclude that prolonged drainage of amniotic and allantoic fluids decreases Vl, Vs, and Vtr in fetal sheep. These findings indicate that fetal lung hypoplasia associated with oligohydramnios may be the result of a prolonged reduction in Vl.

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