Umbilical venous velocity pulsations are related to atrial contraction pressure waveforms in fetal lambs

Reed, Kathryn L.; Chaffin, David G.; Anderson, Caroline F.; Newman, Adam T.

doi:10.1016/s0029-7844(97)00154-3

Cited by 34 publications

(19 citation statements)

References 6 publications

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“…Pressure profiles distant from the heart were delayed with respect to more downstream locations, which is in agreement with the delay of the flow pulses (21). On average, the pressure wave arrived 53 ms later at the entrance of the DV (DV1) than at the inferior VC close to the heart (VC2), and the average time delay for the positions in between varied accordingly.…”

Section: Pulsatile Venous Pressuresupporting

confidence: 76%

“…It can be used also in chronic fetal sheep experiments (21). This may help to explore, in nonanesthetized fetuses, the effects of experimental cardiac failure, for example, on flow and pressures in fetal central veins, and thus to improve for diagnostic purposes the understanding of pathological flow-velocity patterns.…”

Section: Relationship Between Pressure and Flow Pulsesmentioning

confidence: 99%

“…The pressure waves were thought to travel from the heart in a direction opposite to the bloodstream toward the inferior VC and DV. It could be demonstrated accordingly (21) that the delay of flow pulsations in central veins increased with distance from the heart, but it has not been shown directly so far that a pulse wave actually exists, nor has its velocity been determined. Pressure pulses in combination with flow have not been measured in the DV or UV.…”

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confidence: 99%

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Pressure pulses and flow velocities in central veins of the anesthetized sheep fetus

Schröder¹,

Tchirikov²,

Rybakowski

2003

American Journal of Physiology-Heart and Circulatory Physiology

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Schrö der, Hobe J., Mikhail Tchirikov, and Christian Rybakowski. Pressure pulses and flow velocities in central veins of the anesthetized sheep fetus. Am J Physiol Heart Circ Physiol 284: H1205-H1211, 2003. First published December 27, 2002; 10.1152/ajpheart.00969.2002The pressure drop and pressure pulses in the isthmus of the ductus venosus (DV) in fetal sheep have not been measured directly and related to flow. In eight acutely anesthetized fetal sheep, a 3-Fr tip pressure transducer (TP) was inserted from the external jugular into the umbilical vein (UV). Ultrasound Doppler flow velocities, TP position, and intravenous pressures were recorded in the UV, DV, and inferior vena cava (VC) while the TP was withdrawn. Flow was steady in the UV, but small pressure fluctuations (Ͻ0.4 mmHg) could be detected. Time-averaged pressure dropped 1.9 mmHg (mean; 0.5-3.3 mmHg 95% confidence interval) across the DV isthmus. Pressure pulses increased from 1.7 mmHg (mean; 1.2-2.1 mmHg 95% confidence interval) in the DV to 3.9 mmHg (mean; 1.8-6.0 mmHg 95% confidence interval) in the inferior VC. The pressure wave from the heart arrived later [0.053 s (mean; 0.025-0.080 s 95% confidence interval)] in the isthmus of the DV than in the diaphragmatic inferior VC, indicating a wave velocity of ϳ1.1 m/s. At all locations, pressures and flow velocities were inversely related. fetal sheep; pressure wave; flow velocity; ductus venosus IN THE FETUS, flow is pulsatile in both the venae cavae (VC) (22) and ductus venosus (DV) (10) and normally nonpulsatile in the portal sinus or umbilical vein (UV). Variations of the flow rates and/or velocity patterns predominantly in the DV, and their significance for the well-being of human fetuses, have been investigated by Doppler ultrasound and shown to be of diagnostic value (2-4, 8-10, 25). Cardiac and circulatory dysfunction as disclosed by an abnormal flow pattern may be associated with pressure variations, which at present are mostly unknown. However, only the knowledge of both flow and pressure permit sufficient understanding of physiological and pathological conditions in the central venous circulation (11,14,20,22). Mathematical (1,6,7,(18)(19)(20) and in vitro models (5, 13) have been used to gain insight into the complex situation, but empirical in vivo data on these pressure-wave forms and their relation to flow in the fetus are remarkably rare.Pressure pulses were derived indirectly from the wall movement of the inferior vena cava (VC) in human fetuses (16). In fetal sheep, pulsatile pressure and flow were recorded from the superior VC with indwelling catheters and flow probes (22). It was found that local pressure fluctuations were biphasic, as was the flow, but flow and pressure pulses were inverse. It was concluded that flow pulsatility in central veins is generated by pressure waves originating in the heart. The pressure waves were thought to travel from the heart in a direction opposite to the bloodstream toward the inferior VC and DV. It could be demonstrated accordingly (21) that the...

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Section: Pulsatile Venous Pressuresupporting

confidence: 76%

Section: Relationship Between Pressure and Flow Pulsesmentioning

confidence: 99%

mentioning

confidence: 99%

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Pressure pulses and flow velocities in central veins of the anesthetized sheep fetus

Schröder¹,

Tchirikov²,

Rybakowski

2003

American Journal of Physiology-Heart and Circulatory Physiology

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“…We found visible pulsation in the umbilical vein at the abdominal inlet (umbilical ring) in 242/279 participants (87%, 95% CI 82-90), which was more common than in the cord (43/198, 22%, 95% CI [16][17][18][19][20][21][22][23][24][25][26][27] and in the intra-abdominal section of the vein (84/277, 30%, 95% CI 25-36) (P < 0.001) (Figure 2).…”

Section: Resultsmentioning

confidence: 97%

“…The commonly recorded pulsation in the portal system during the second half of a normal pregnancy 18,23 may have a similar reason: the transverse portal sinus (left portal branch) has a considerably smaller dimension compared to the umbilical vein 24 . During abnormal cardiac physiology 25,26 an augmented atrial contraction is transmitted along the inferior vena cava and ductus venosus, which act as a transmission line to reach the intra-abdominal umbilical vein 9,15 . During hypoxia the ductus venosus distends 27,28 and reduces the reflections that normally take away most of the pulse energy before it reaches the umbilical vein 15 .…”

Section: Discussionmentioning

confidence: 99%

The effect of vascular constriction on umbilical venous pulsation

Skulstad¹,

Kiserud²,

Rasmussen³

2003

Ultrasound in Obstet & Gyne

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Objectives Results The incidence of umbilical venous pulsation was higher at the umbilical ring in the abdominal wall (242/279, 87%, than in the cord (43/198,22%,30%, (P < 0.001). When pulsation was observed intra-abdominally, the pulsatility was not different from that at the umbilical ring (P = 0.16). However, the lowest pulsatility was found in the cord vein (P < 0.0001), where the largest vein diameter was found. ConclusionThe high incidence of venous pulsation at the umbilical ring where diameter and compliance are low supports the suggestion that local compliance is an important factor influencing pulsation in fetal veins.

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Helical Molecular Programming: Supramolecular Double Helices by Dimerization of Helical Oligopyridine-dicarboxamide Strands

Berl¹,

Huc²,

Khoury³

et al. 2001

Chem. Eur. J.

204

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Helically preorganized oligopyridine-dicarboxamide strands are found to undergo dimerization into double helical supramolecular architectures. Dimerization of single helical strands with five or seven pyridine rings has been characterized by NMR and mass spectrometry in various solvent/ temperature conditions. Solution studies and stochastic dynamic simulations consistently show an increasing duplex stability with increasing strand length. The double helical structures of three different dimers was characterized in the solid phase by X-ray diffraction analysis. Both aromatic stacking and hydrogen bonding contribute the double helical arrangement of the oligopyridinedicarboxamide strand. Inter-strand interactions involve extensive face-to-face overlap between aromatic rings, which is not possible in the single helical monomers. Most hydrogen bonds occur within each strand of the duplex and stabilize its helical shape. Some inter-strand hydrogen bonds are found in the crystal structures. Dynamic studies by NMR as well as by molecular modeling computations yield structural and kinetic information on the double helices and on monomer-dimer interconversion. In addition, they reveal the presence of a spring-like extension/compression as well as rotational displacement motions.

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Umbilical venous velocity pulsations are related to atrial contraction pressure waveforms in fetal lambs

Abstract: Transmission time of atrial pressure into the venous circulation increases with distance from the atrium and decreases with volume loading. Umbilical venous velocity pulsations derive from atrial pressure changes transmitted in a retrograde fashion.

Cited by 34 publications

References 6 publications

Pressure pulses and flow velocities in central veins of the anesthetized sheep fetus

Pressure pulses and flow velocities in central veins of the anesthetized sheep fetus

The effect of vascular constriction on umbilical venous pulsation

Helical Molecular Programming: Supramolecular Double Helices by Dimerization of Helical Oligopyridine-dicarboxamide Strands

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