Fetal oxygenation and Doppler ultrasonography of cardiovascular hemodynamics in a chronic near-term sheep model

Mäkikallio, Kaarin; Erkinaro, Tiina; Niemi, Niina; Kavasmaa, Tomi; Acharya, Ganesh; Päkkilä, M.; Räsänen, Juha

doi:10.1016/j.ajog.2005.08.028

Cited by 41 publications

(42 citation statements)

References 20 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…30 In addition, experimental studies on fetal sheep have shown that by decreasing maternal inspiratory oxygen content, fetal partial oxygen tension decreases. 10,11 Based on these results, our experimental model is sufficient to modify fetal partial oxygen tension. Intraobserver variability in the measurements of different blood velocity waveform indices could introduce a potential error.…”

Section: Commentmentioning

confidence: 96%

“…Previous experimental studies have shown that during hypoxemia, fetal cardiac output, especially the right ventricular output, increases. 10 In the present study, we applied maternal hypoxemia only for a short time period, which could explain the unchanged cardiac output.…”

Section: Commentmentioning

confidence: 99%

“…[4][5][6] Recent experimental and clinical studies have demonstrated that fetal pulmonary arterial circulation becomes responsive to fetal oxygen status toward the term of pregnancy. [7][8][9][10][11] In sheep fetuses, studies have shown that acute fetal hypoxemia increases pulmonary arterial vascular impedance. 10 In human fetuses, it has been demonstrated that an increase in fetal oxygenation leads to decreased pulmonary vascular impedance and increased pulmonary volume blood flow.…”

Section: Introductionmentioning

confidence: 99%

“…[7][8][9][10][11] In sheep fetuses, studies have shown that acute fetal hypoxemia increases pulmonary arterial vascular impedance. 10 In human fetuses, it has been demonstrated that an increase in fetal oxygenation leads to decreased pulmonary vascular impedance and increased pulmonary volume blood flow. 7 This acquired ability of the pulmonary arteries to vasoconstrict or vasodilate during the last trimester has been attributed to the development of smooth muscle in small pulmonary arteries.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Fetal Pulmonary Arterial Vascular Impedance Reflects Changes in Fetal Oxygenation at Near-Term Gestation in a Nonhuman Primate Model

et al. 2013

View full text Add to dashboard Cite

Objective: We tested the hypothesis that fetal pulmonary arterial circulation reacts to changes in fetal oxygenation status at near-term gestation. Study Design: A total of 20 rhesus macaques underwent fetal Doppler ultrasonography at near-term gestation. Right pulmonary artery (RPA), umbilical artery (UA), ductus arteriosus (DA), and ductus venosus (DV) blood velocity waveforms were obtained, and pulsatility index (PI) values were calculated. Fetal right and left ventricular cardiac outputs were determined. Ultrasonographic data were collected during 3 maternal oxygenation states: room air (baseline), hyperoxemia, and hypoxemia. Results: Fetal RPA PI values increased (P < .05) during maternal hypoxemia and decreased (P < .05) during maternal hyperoxemia, compared with baseline. Maternal hyperoxemia increased (P < .05) DA PI values from baseline. Fetal cardiac outputs, UA, and DV PI values were not affected. Conclusions: Our results demonstrate that at near-term gestation, fetal pulmonary arterial circulation is a dynamic vascular bed that reflects acute and short-term changes in fetal oxygenation.

show abstract

Section: Commentmentioning

confidence: 96%

Section: Commentmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Fetal Pulmonary Arterial Vascular Impedance Reflects Changes in Fetal Oxygenation at Near-Term Gestation in a Nonhuman Primate Model

et al. 2013

View full text Add to dashboard Cite

show abstract

“…In ovine fetuses, a stepwise increase in resistance to placental blood flow lowers oxygen delivery to the brain in association with a major reversal of diastolic blood flow through the aortic isthmus (7,19). Oxygen delivery to the brain decreases as the net flow through the aortic isthmus becomes retrograde (18,19,35,54).…”

mentioning

confidence: 99%

Phasic hemodynamics and reverse blood flows in the aortic isthmus and pulmonary arteries of preterm lambs with pulmonary vascular dysfunction

Rolland¹,

Stathopoulos²,

Leprêtre³

et al. 2008

American Journal of Physiology-Heart and Circulatory Physiology

View full text Add to dashboard Cite

Time-domain representations of the fetal aortopulmonary circulation were carried out in lamb fetuses to study hemodynamic consequences of congenital diaphragmatic hernia (CDH) and the effects of endothelin-receptor antagonist tezosentan (3 mg/45 min). From the isthmic aortic and left pulmonary artery (PA) flows (Q) and isthmic aortic, PA, and left auricle pressures (P) on day 135 in 10 controls and 7 CDH fetuses (28 ewes), discrete-triggered P and Q waveforms were modelized as P t and Qt functions to obtain basic hemodynamic profiles, pulsatile waves [P, Q, and entry impedance (Z e)], and P and Q hysteresis loops. In the controls, blood propelling energy was accounted for by biventricular ejection flow waves (kinetic energy) with low Ze and by flow-driven pressure waves (potential energy) with low Z e. Weak fetal pulmonary perfusion was ensured by reflux (reverse flows) from PA branches to the ductus anteriosus and aortic isthmus as reverse flows. Endothelin-receptor antagonist blockade using tezosentan slightly increased the forward flow but largely increased diastolic backward flow with a diminished left auricle preand postloading. In CHD fetuses, the static component overrode phasic flows that were detrimental to reverse flows and the direction of the diastolic isthmic flow changed to forward during the diastole period. Decreased cardiac output, flattened pressure waves, and increased forward Ze promoted backward flow to the detriment of forward flow (especially during diastole). Additionally, the intrapulmonary arteriovenous shunting was ineffective. The slowing of cardiac output, the dampening of energetic pressure waves and pulsatility, and the heightening of phasic impedances contributed to the lowering of aortopulmonary blood flows. We speculate that reverse pulmonary flow is a physiological requirement to protect the fetal pulmonary circulation from the prominent right ventricular stream and to enhance blood flow to the fetal heart and brain. fetal pulmonary circulation; congenital diaphragmatic hernia; pulmonary reverse flows; pulsatile impedance; endothelin receptor inhibitor THE PULMONARY CIRCULATION in the preterm fetal lamb (see Fig. 1) is hemodynamically unique because the distribution of the combined ventricular output is 40% to the placenta versus only about 7% to the lungs (1,22,33,51,52). Central vascular shunting leads to a communication of the pulmonary and aortic circulation with driving pressures that would be considered as hypertensive if it persisted after birth (1, 14, 47). These characteristics are functionally optimal for the fetal lung that does not participate in gas exchange and requires only a small amount of blood for development (14,23,25,27,47). In previous studies we used the preterm fetal lamb model to study lung hypoplasia caused by a congenital diaphragmatic hernia (11, 61) and the porcine thoracic and abdominal aorta model to study anatomical bypass-and stenting-induced hemodynamic changes (38,39,48). The purpose of the present study was to investigate two hypotheses that ...

show abstract

Aortic isthmus shunt dynamics in normal and complicated monochorionic pregnancies

et al. 2017

View full text Add to dashboard Cite

show abstract

Fetal oxygenation and Doppler ultrasonography of cardiovascular hemodynamics in a chronic near-term sheep model

Cited by 41 publications

References 20 publications

Fetal Pulmonary Arterial Vascular Impedance Reflects Changes in Fetal Oxygenation at Near-Term Gestation in a Nonhuman Primate Model

Fetal Pulmonary Arterial Vascular Impedance Reflects Changes in Fetal Oxygenation at Near-Term Gestation in a Nonhuman Primate Model

Phasic hemodynamics and reverse blood flows in the aortic isthmus and pulmonary arteries of preterm lambs with pulmonary vascular dysfunction

Aortic isthmus shunt dynamics in normal and complicated monochorionic pregnancies

Contact Info

Product

Resources

About