Volumetric flow in the umbilical artery: Normative data

Goldkrand, John W.; Moore, Daniel H.; Lentz, S. U.; Clements, S. P.; Turner, Angela D.; Bryant, J. L.

doi:10.1002/1520-6661(200007/08)9:4<224::aid-mfm7>3.3.co;2-n

Cited by 10 publications

(9 citation statements)

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“…Therefore, the catheters used were small, with diameters of 3.5 Fr (∼1.2 mm) used for the umbilical artery and 6.5 Fr (∼2.2 mm) for the umbilical vein. However, depending on the gestational age, the umbilical artery has a diameter of 3-4 mm and the umbilical vein has a diameter of 6-9 mm (27,28), allowing 90-180 mL/kg/ min of blood circulation in utero through the placenta (29). This suggests that if the LAD is attached immediately after birth using a larger catheter, it could lower the pressure drop.…”

Section: Discussionmentioning

confidence: 99%

An Integrated Array of Microfluidic Oxygenators as a Neonatal Lung Assist Device: In Vitro Characterization and In Vivo Demonstration

Rochow

Manan

et al. 2014

Artificial Organs

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A miniaturized oxygenator device that is perfused like an artificial placenta via the umbilical vessels may have significant potential to save the lives of newborns with respiratory insufficiency. Recently we presented the concept of an integrated modular lung assist device (LAD) that consists of stacked microfluidic single oxygenator units (SOUs) and demonstrated the technical details and operation of SOU prototypes. In this article, we present a LAD prototype that is designed to accommodate the different needs of term and preterm infants by permitting changing of the number of parallel-stacked microfluidic SOUs according to the actual body weight. The SOUs are made of polydimethylsiloxane, arranged in parallel, and connected though 3D-printed polymeric interconnects to form the LAD. The flow characteristics and the gas exchange properties were tested in vitro using human blood. We found that the pressure drop of the LAD increased linearly with flow rate. Gas exchange rates of 2.4-3.8 μL/min/cm(2) (0.3-0.5 mL/kg/min) and 6.4-10.1 μL/min/cm(2) (0.8-1.3 mL/kg/min) for O2 and CO2 , respectively, were achieved. We also investigated protein adsorption to provide preliminary information on the need for application of anticoagulant coating of LAD materials. Albumin adsorption, as measured by gold staining, showed that surface uptake was evenly distributed and occurred at the monolayer level (>0.2 μg/cm(2) ). Finally, we also tested the LAD under in vivo conditions using a newborn piglet model (body weight 1.65-2.0 kg). First, the effect of an arteriovenous bypass via a carotid artery-to-jugular vein shortcut on heart rate and blood pressure was investigated. Heart rate and mean arterial blood pressure remained stable for extracorporeal flow rates of up to 61 mL/kg/min (101 mL/min). Next, the LAD was connected to umbilical vessels (maximum flow rate of 24 mL/min [10.4 mL/kg/min]), and O2 gas exchange was measured under hypoxic conditions (Fi O2 = 0.15) and was found to be 3.0 μL/min/cm(2) . These results are encouraging and support the feasibility of an artificial placental design for an LAD.

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Section: Discussionmentioning

confidence: 99%

An Integrated Array of Microfluidic Oxygenators as a Neonatal Lung Assist Device: In Vitro Characterization and In Vivo Demonstration

Rochow

Manan

et al. 2014

Artificial Organs

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“…This may be particularly relevant since there is little or no control of the lateral extension of the sample volume during the measurements. It has previously been attempted to calculate fetoplacental blood flow using the maximum velocity recording in the UA31, which resulted in higher values than are achieved by the assessment of umbilical venous flow. Our findings suggest that it may be more appropriate to use 0.6*TAMXV rather than 0.5*PSV for placental volume flow estimation.…”

Section: Discussionmentioning

confidence: 99%

Doppler‐derived umbilical artery absolute velocities and their relationship to fetoplacental volume blood flow: a longitudinal study

Acharya

Wilsgaard

Berntsen

et al. 2005

Ultrasound in Obstet & Gyne

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“…Animal and human studies show that the ability of the uteroplacental unit to support the fetus diminishes steadily as gestation advances. [27][28][29] It is estimated that the average uterine blood flow volume per unit of estimated fetal weight declines from 993 mL/min/kg at 24 weeks to 360 mL/min/kg at 34 weeks and to 296 mL/min/kg at 38 weeks' gestation in humans. 28 This provides the theoretical basis for the obstetric practice of routinely inducing labour in all pregnancies at post-term gestation and even earlier in high-risk pregnancies.…”

Section: Biological Basis For Birth Patterns and Late Gestation Chamentioning

confidence: 99%

Towards a unified perinatal theory: Reconciling the births‐based and fetus‐at‐risk models of perinatal mortality

Joseph

2019

Paediatric Perinatal Epid

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Background There is a need to reconcile the opposing perspectives of the births‐based and fetuses‐at‐risk models of perinatal mortality and to formulate a coherent and unified perinatal theory. Methods Information on births in the United States from 2004 to 2015 was used to calculate gestational age‐specific perinatal death rates for low‐ and high‐risk cohorts. Cubic splines were fitted to the fetuses‐at‐risk birth and perinatal death rates, and first and second derivatives were estimated. Births‐based perinatal death rates, and fetuses‐at‐risk birth and perinatal death rates and their derivatives, were examined to identify potential inter‐relationships. Results The rate of change in the birth rate dictated the pattern of births‐based perinatal death rates in a triphasic manner: increases in the first derivative of the birth rate at early gestation corresponded with exponential declines in perinatal death rates, the peak in the first derivative presaged the nadir in perinatal death rates, and late gestation declines in the first derivative coincided with an upturn in perinatal death rates. Late gestation increases in the first derivative of the fetuses‐at‐risk perinatal death rate matched the upturn in births‐based perinatal death rates. Differences in birth rate acceleration/deceleration among low‐ and high‐risk cohorts resulted in intersecting perinatal mortality curves. Conclusion The first derivative of the birth rate links a cohort's fetuses‐at‐risk perinatal death rate to its births‐based perinatal death rate, and cohort‐specific differences in birth rate acceleration/deceleration are responsible for the intersecting perinatal mortality curves paradox. This mechanistic explanation unifies extant models of perinatal mortality and provides diverse insights.

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Volumetric flow in the umbilical artery: Normative data

Cited by 10 publications

References 0 publications

An Integrated Array of Microfluidic Oxygenators as a Neonatal Lung Assist Device: In Vitro Characterization and In Vivo Demonstration

An Integrated Array of Microfluidic Oxygenators as a Neonatal Lung Assist Device: In Vitro Characterization and In Vivo Demonstration

Doppler‐derived umbilical artery absolute velocities and their relationship to fetoplacental volume blood flow: a longitudinal study

Towards a unified perinatal theory: Reconciling the births‐based and fetus‐at‐risk models of perinatal mortality

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