A mathematical model of umbilical venous pulsation

Hellevik, Leif Rune; Stergiopulos, Nikolaos; Kiserud, Torvid; Rabben, Stein Inge; Eik‐Nes, S. H.; Irgens, Fridtjov

doi:10.1016/s0021-9290(00)00041-5

Cited by 34 publications

(46 citation statements)

References 25 publications

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“…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).…”

Section: Results the Incidence Of Umbilical Venous Pulsation Was Highmentioning

confidence: 87%

“…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%

“…

ABSTRACT

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).

…”

mentioning

confidence: 92%

“…In a computer model it was shown that a stronger pulse was needed to induce velocity pulsation in a compliant compared to a less compliant umbilical vein 13 . Compliance in the umbilical vein is determined by vascular wall stiffness 19 , transmural pressure and vessel cross-sectional area.…”

Section: Introductionmentioning

confidence: 99%

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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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“…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).…”

Section: Results the Incidence Of Umbilical Venous Pulsation Was Highmentioning

confidence: 87%

Section: Resultsmentioning

confidence: 97%

“…

ABSTRACT

Objectives

…”

mentioning

confidence: 92%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

The effect of vascular constriction on umbilical venous pulsation

Skulstad¹,

Kiserud²,

Rasmussen³

2003

Ultrasound in Obstet & Gyne

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show abstract

“…In the present case, a grossly abnormal blood flow pattern was detected 8 weeks before delivery. We attributed this finding to the anatomical variant of a DV draining into the inferior vena cava instead of the subdiaphragmatic vestibulum 2 , with the abnormal branching angle possibly affecting the transmission of atrial contraction waveforms 6 . Antenatally, the differential diagnosis included a portocaval shunt with agenesis of the DV, and an abnormal umbilical venous return with the umbilical vein draining directly into the inferior vena cava.…”

mentioning

confidence: 99%

Clinical implications of an anatomical variant of the ductus venosus

Prefumo

Celentano²,

Casagrande

et al. 2006

Ultrasound in Obstet & Gyne

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A 29-year-old primigravida was referred at 25 weeks of gestation for evaluation of a growth discrepancy in a monochoronic diamniotic twin pregnancy. On ultrasound examination, the first fetus appeared to have grown normally, while biometry was consistently below the 5 th centile in the second fetus. In this small-for-gestational age (SGA) fetus, the umbilical artery pulsatility index (PI) was above the 95 th centile for gestation, and the middle cerebral artery PI was within the normal range. A diagnosis of selective early-onset intrauterine growth restriction (IUGR) was made. Color Doppler was used to image the ductus venosus (DV). The DV originated normally as a branchless straight vessel from the portal sinus 1,2 . However, instead of converging together with the hepatic veins into the subdiaphragmatic vestibulum, the DV drained separately into the inferior vena cava, approximately 1 cm below the right atrium (Figures 1 and 2). Pulsed wave Doppler demonstrated an abnormal pattern of flow with reversed A-wave velocities. Reversed flow in the DV is usually indicative of fetal compromise 3,4 . Albeit growth-restricted, the fetus did not demonstrate any other signs of severe fetal distress on umbilical and middle cerebral artery Doppler, biophysical profile score (BPS), or computerized cardiotocography (cCTG), and the pathological waveform in the DV was attributed to the abnormal anatomical arrangement. It was therefore decided not to use DV Doppler findings for timing the delivery. In the following weeks, all monitoring parameters remained within the normal ranges, except for a gradually increasing umbilical resistance in the SGA twin. At 32 + 5 weeks, reversed end-diastolic flow was demonstrated in the umbilical artery. Given the normal BPS and cCTG, a full course of steroids was given, and two male infants weighing 1730 g and 1420 g were delivered by elective Cesarean section at 33 + 3 weeks. On day 4, an abdominal ultrasound examination was performed on Twin 2, confirming normal liver vascular anatomy and the spontaneous closure of the DV. Both newborns developed severe respiratory distress syndrome and Staphylococcus epidermidis sepsis. Twin 1 recovered uneventfully, while Twin 2 died on day 20. Placental examination confirmed the diagnosis of a monochorionic diamniotic placenta, with velamentous insertion of the cord of Twin 2 and angiodystopias. The parents did not consent to a postmortem examination.DV Doppler is being used increasingly for fetal assessment in cases of early onset IUGR 4 , and its role is currently being investigated in a large randomized trial 5 . In the present case, a grossly abnormal blood flow pattern was detected 8 weeks before delivery. We attributed this finding to the anatomical variant of a DV draining into the inferior vena cava instead of the subdiaphragmatic vestibulum 2 , with the abnormal branching angle possibly affecting the transmission of atrial contraction waveforms 6 . Antenatally, the differential diagnosis included a portocaval shunt with agenesis of the DV, and an ...

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Quantifying the hydrodynamic stress for bioprocesses

Kaya

Gopireddy

Urbanetz

et al. 2023

Biotechnology Progress

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Hydrodynamic stress is an influential physical parameter for various bioprocesses, affecting the performance and viability of the living organisms. However, different approaches are in use in various computational and experimental studies to calculate this parameter (including its normal and shear subcomponents) from velocity fields without a consensus on which one is the most representative of its effect on living cells. In this letter, we investigate these different methods with clear definitions and provide our suggested approach which relies on the principal stress values providing a maximal distinction between the shear and normal components. Furthermore, a numerical comparison is presented using the computational fluid dynamics simulation of a stirred and sparged bioreactor. It is demonstrated that for this specific bioreactor, some of these methods exhibit quite similar patterns throughout the bioreactor—therefore can be considered equivalent—whereas some of them differ significantly.

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A mathematical model of umbilical venous pulsation

Cited by 34 publications

References 25 publications

The effect of vascular constriction on umbilical venous pulsation

The effect of vascular constriction on umbilical venous pulsation

Clinical implications of an anatomical variant of the ductus venosus

Quantifying the hydrodynamic stress for bioprocesses

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