Normal values for human umbilical venous and amniotic fluid pressures and their alteration by fetal disease

Weiner, Carl P.; Heilskov, Joni; Grant, Stanley S.; Wenstrom, Katharine D.; Williamson, Roger A.

doi:10.1016/0002-9378(89)90387-6

Cited by 91 publications

(50 citation statements)

References 1 publication

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“…Hence, for the normal symmetric case, we assumed that the flow into each artery is Q 1 ϭ Q2 ϭ 250 ml/min. The published data for arterial pressure in the umbilical arteries ranges between 2,665 and 10,665 Pa (20 -80 mmHg) (20,28,29). For the present model (Fig.…”

Section: Methodsmentioning

confidence: 62%

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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: 62%

“…For the present model (Fig. 1B), we assumed that the normal inlet pressure is P inlet-N ϭ 5,150 Pa (38.6 mmHg), similar to the data of Weiner et al (29). The outlet of the model is assumed to be at the level of fetal capillaries within the cotyledons; hence, P outlet ϭ 1,200 Pa (9 mmHg) (14,15).…”

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 amniotic fluid pressure of women presenting hydramnios has been found to be ,40% higher than that of healthy patients [35]. 8 One large study [36] amid other contradictory results [37][38][39][40][41][42] tends to confirm this hypothesis.…”

Section: Etiologymentioning

confidence: 99%

Biomechanics of the human chorioamnion

Prevost¹,

Suresh²,

House³

et al. 2006

Journal of Biomechanics

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The human fetal membrane, namely the chorioamnion, is the structural soft tissue retaining the amniotic fluid and the fetus during pregnancy. Its biomechanical integrity is crucial for maintaining a healthy gestation and a successful delivery. The premature rupture of the fetal membrane (PROM) can result in serious perinatal complications. Despite extensive research in this field, the mechanical and biochemical processes governing the membrane deformation and failure remain poorly understood. The aim of this study is to characterize the mechanical behavior of the chorioamnionic tissue along with its biochemical properties, through mechanical testing and biochemical analyses. In order to accomplish this goal, specific mechanical and biochemical testing protocols were developed. In vitro mechanical testing was performed on samples from seven patients under different uniaxial and biaxial loading conditions. Significant relaxation was noted under uniaxial loading while very limited creep was observed under biaxial loading. Biochemical measurements such as collagen and sulfated glycosaminoglycan contents were also obtained. In addition, a microstructurally based constitutive model for the fetal membrane is proposed. The model allows for nonlinear hyperelastic response at large deformation. We also propose a framework to capture the timedependent response of the tissue. The model was implemented in a finite element formulation to allow three-dimensional simulations of membrane deformation.

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“…The initial load on the preparation was adjusted gradually to 200-300 mg (100 mg weight ¼ 0.98 mN) with both preterm and term animals. This value had been extrapolated from the transmural tension in vivo (Adeagbo et al, 1982) and was kept constant regardless of age knowing that intraluminal pressure does not change appreciably during the last third of gestation (Nicolini et al, 1989;Weiner et al, 1989). Each bath was supplied from several reservoirs, and a system of three-way valves allowed the perfusion fluid to be changed rapidly.…”

Section: Pharmacological Analysismentioning

confidence: 99%

Endothelin‐induced constriction of the ductus venosus in fetal sheep: developmental aspects and possible interaction with vasodilatory prostaglandin

Adeagbo

Kelsey

Coceani

2004

British J Pharmacology

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1 The ductus venosus is actively regulated in the fetus, but questions remain on the presence of a functional sphincter at its inlet. Using fetal sheep (0.6-0.7 gestation onwards), we have examined the morphology of the vessel and have also determined whether endothelin-1 (ET-1) qualifies as a natural constrictor being modulated by prostaglandins (PGs). 2 Masson's staining and a-actin immunohistochemistry showed a muscular, sphincter-like formation at the ductus inlet and a muscle layer within the wall of the vessel proper. This muscle cell component increased with age. 3 ET-1 contracted dose-dependently isolated sphincter and extrasphincter preparations of the ductus from term fetus. This ET-1 effect also occurred in the premature, but its threshold was higher. 4 BQ123 (1 mM) caused a rightward shift in the ET-1 dose-response curve, while indomethacin at a threshold concentration (28 nM) tended to have an opposite effect. 5 Big ET-1 also contracted the ductus sphincter but differed from ET-1 for its lesser potency and inhibition by phosphoramidon (50 mM). 6 The ductus sphincter (term and preterm) and extrasphincter (term) released 6-keto-PGF 1a (hence PGI 2 ) and, to a lesser degree, PGE 2 at rest and their release increased dose-dependently upon ET-1 treatment. Both basal and stimulated release was curtailed by endothelium removal. 7 BQ123 and phosphoramidon reduced slightly the contraction of ductus sphincter to indomethacin (2.8 mM). 8 We conclude that the ductus contains a contractile mechanism in the sphincter and extrasphincter regions. ET-1 lends itself to a role in the generation of contractile tone and its action may be modulated by prostaglandins.

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Normal values for human umbilical venous and amniotic fluid pressures and their alteration by fetal disease

Cited by 91 publications

References 1 publication

Hemodynamic analysis of Hyrtl anastomosis in human placenta

Hemodynamic analysis of Hyrtl anastomosis in human placenta

Biomechanics of the human chorioamnion

Endothelin‐induced constriction of the ductus venosus in fetal sheep: developmental aspects and possible interaction with vasodilatory prostaglandin

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