How repeat measurements affect the mean diameter of the umbilical vein and the ductus venosus

Kiserud, Torvid; Rasmussen, Svein

doi:10.1046/j.1469-0705.1998.11060419.x

Cited by 76 publications

(63 citation statements)

References 20 publications

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“…The 6% difference may be ascribed to technique (this study measured between valves at the ostium), or to chance. Knowing the variability of such measurements in the fetus 31,32 , particularly diameter measurements, we restricted error by repeating measurements 12,33 and by using a single operator. Coefficients of variation of 8.4 and 7.7%, and intraclass correlations of 94 and 97% for the diameter of the aorta and pulmonary artery, respectively, ensured that the study gave a fair representation of normal and abnormal flows.…”

Section: Discussionmentioning

confidence: 99%

Fetal cardiac output, distribution to the placenta and impact of placental compromise

Kiserud

Ebbing

Kessler

et al. 2006

Ultrasound in Obstet & Gyne

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238

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Section: Discussionmentioning

confidence: 99%

Fetal cardiac output, distribution to the placenta and impact of placental compromise

Kiserud

Ebbing

Kessler

et al. 2006

Ultrasound in Obstet & Gyne

Self Cite

238

198

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“…Repeat measurement has shown to reduce random error (21) and was practiced for all diameter measurements in the study. Because less susceptible to error than intensity weighted mean velocity, we used the time averaged V max corrected by a velocity profile factor for flow calculation.…”

Section: Discussionmentioning

confidence: 99%

“…Vessel diameter was measured in a perpendicular insonation to the vessel wall. Diameter was measured repeatedly (UV, LPV, PV: median 4 times, DV: median 5) to reduce random error (21) and the mean diameter was used for further analysis. At the same site, with an insonation along the vessel axis, flow velocities (time-averaged maximum flow velocity, TAMXV) were measured using pulsed Doppler.…”

Section: Measurementmentioning

confidence: 99%

Longitudinal Study of Umbilical and Portal Venous Blood flow to the Fetal Liver: Low Pregnancy Weight Gain is Associated With Preferential Supply to the Fetal Left Liver Lobe

et al. 2008

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Recent data suggest that umbilical venous perfusion of the fetal liver has an important influence on fetal growth and postnatal liver function, and that maternal factors in late pregnancy modify this circulation. In a longitudinal study of 160 low-risk pregnancies, we determined how umbilical and portal venous blood flows to the fetal liver changed during gestation, and examined the hypothesis that maternal body mass index and pregnancy weight gain influenced fetal liver blood flows. We measured blood flows in the umbilical and portal veins, left portal branch, and ductus venosus using ultrasound. Normalizing for estimated fetal weight, fetal liver total venous blood flow fell from 84 to 57 mL ⅐ min Ϫ1 ⅐ kg Ϫ1 during 21-39 wk of gestation; toward term the portal contribution increased (from 14 to 20%) and the umbilical contribution fell, whereas distribution between the left and right liver lobes was stable, 60%/ 40%. Greater flow of nutrient-rich umbilical venous blood to the liver was associated with higher birth weight and neonatal ponderal index. Maternal body mass index was not related to fetal liver blood flows, but low pregnancy weight gain strongly influenced flow distribution between the right and left liver lobes, sparing the left lobe and increasing the difference between lobes by 16%. T he developmental origins of health and disease hypothesis established a link between an adverse intrauterine environment and cardiovascular disease in adult life (1,2). There is strong evidence from epidemiologic studies and animal experiments that an adverse intrauterine environment is associated with raised levels of cardiovascular risk factors controlled by the liver (3). The role of the fetal liver for intrauterine growth and development has therefore come into focus of research.In fetal sheep, experimental reduction in umbilical venous liver perfusion results in decreased synthesis of insulin-like growth factors by the fetal liver, decreasing the cellular proliferation rate in peripheral tissues and impairing fetal growth (4,5). In human fetuses, venous liver blood flow was shown to be modulated by maternal diet and body composition (6).The fetal liver receives venous blood from the umbilical and portal veins (PVs). The umbilical vein (UV) directs nutrient-rich placental blood predominantly to the left liver lobe, whereas nutrient-depleted blood from the PV is directed to the right liver lobe (7). This selective perfusion pattern is thought to be the main reason for differences in micro architecture (8), hematopoiesis (9) and gene and enzyme expression (10,11).Although single components of the venous liver circulation such as umbilical blood flow (12-14) and shunting through the ductus venosus (DV) (15,16) have been investigated earlier, little is known about the distributions of umbilical and portal blood flows in the human fetus.The aim of the present study was to study simultaneously the umbilical and portal venous circulations and the blood flow distribution to the liver lobes in the second half of ...

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“…Another important source of variation is the error of measurement in small vessels. The diameter measurement in small vessels (0.5-2.5 mm) has an upper 95% con®dence limit of 0.15 mm when the diameter is determined as the average of ®ve measurements 15 . We are not sure that our assumption of a circular cross-section is valid for this section of the vein.…”

Section: Discussionmentioning

confidence: 99%

“…Alternatively, the measurement was done as a transection to obtain a circular cross-section. The diameter was determined as an average of $5 repeat measurements 15 . The blood velocity was recorded at the same site but in a new insonation along the long axis of the vessel and with an expanded sample volume, in order to include the entire cross-section of the vessel.…”

Section: Methodsmentioning

confidence: 99%

The development of high venous velocity at the fetal umbilical ring during gestational weeks 11–19

Skulstad

Rasmussen

Iversen

et al. 2001

BJOG

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Objective To determine the occurrence of high venous velocities at the umbilical ring in the normal early second trimester, based on the assumption that a narrow umbilical ring may cause obstruction and increased venous blood velocity at the abdominal wall.Design Cross-sectional study. Setting Hospital antenatal clinic.Population One hundred and one low risk singleton pregnancies speci®cally recruited for the study.Methods Ultrasound was used at 11±19 weeks to determine the diameter and velocity in the umbilical vein at the fetal end of the cord and at the inlet through the abdominal wall. Outcome measures 10th, 50th and 90th centiles were estimated for the time-averaged maximum velocity in the cord and at the abdominal inlet. The increase of velocity as the blood entered the abdominal wall was calculated in percent of the velocity in the cord.Results During weeks 11-12 there was hardly any difference between blood velocity in the umbilical vein at the umbilical ring and that in the cord. From week 13 onwards it was increasingly common to ®nd blood acceleration at the umbilical ring of 50±500%. Velocity increment .50% was found in 0/12 fetuses (0%) at 11±12 weeks, 5/20 (25%) at 13±14 weeks, and in 21/28 (75%) at 17±19 weeks. Conclusions Blood velocity is higher in the umbilical vein at the abdominal wall than the cord, particularly after 13 weeks of gestation. If acceleration of blood velocity at the umbilical ring is a sign of a narrow inlet, it seems that a progressive tightening occurs during the second trimester.

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How repeat measurements affect the mean diameter of the umbilical vein and the ductus venosus

Cited by 76 publications

References 20 publications

Fetal cardiac output, distribution to the placenta and impact of placental compromise

Fetal cardiac output, distribution to the placenta and impact of placental compromise

Longitudinal Study of Umbilical and Portal Venous Blood flow to the Fetal Liver: Low Pregnancy Weight Gain is Associated With Preferential Supply to the Fetal Left Liver Lobe

The development of high venous velocity at the fetal umbilical ring during gestational weeks 11–19

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