Umbilical Venous Research Articles

Real-Time Ultrasound Tip Location Reduces Malposition and Radiation Exposure during Umbilical Venous Catheter Placement in Neonates: A Retrospective, Observational Study

Introduction: The umbilical venous catheter is a vital access device in neonatal intensive care units for preterm and critically ill infants. Correct positioning is crucial, as malpositioning can lead to severe complications. According to international guidelines, the position of the umbilical venous catheter tip must be assessed in real time; traditionally, the catheter is visualized with a thoracoabdominal X-ray, but one of the most effective and safest methods is therefore real-time ultrasound. Methods: This study compares real-time ultrasound and traditional X-ray methods for assessing umbilical venous catheter tip location in 461 cases. The rate of tip malposition was analyzed retrospectively. The secondary aim was to assess indwelling time of umbilical venous catheters and reasons of removal. Results: Real-time ultrasound tip location, found to be more reliable and efficient, demonstrated a significantly lower incidence of primary malpositioning compared to X-ray assessments (9.6 vs. 75.9%). The study also highlighted the association of real-time ultrasound with reduced catheter manipulation, fewer radiographs, and higher indwelling times of umbilical venous catheter. The multiple logistic regression showed a high probability of the central safe position of the umbilical venous catheter tip using real-time ultrasound tip location (odds ratio 29.5, 95% confidence interval: 17.4–49.4). Conclusion: The findings support the adoption of real-time ultrasound in clinical settings to enhance umbilical venous catheter placement accuracy and minimize associated risks. A minimal training investment is needed to attain the proficiency to visualize the umbilical venous catheters, offering a substantial advantage in terms of both cost-effectiveness for the procedure and enhanced patient safety.

Systematic Quantitative Analysis of Fetal Dexamethasone Exposure and Fetal Lung Maturation in Pregnant Animals: Model Informed Dexamethasone Precision Dose Study.

Dexamethasone (DEX) was applied in neonatal respiratory distress syndrome treatment of pregnant women. We established a pharmacokinetics (PK)/pharmacodynamics(PD)/end point model of pregnant animals based on published data and then extrapolated to simulate fetal exposure and lung maturation in pregnant women. We first established the PK/PD/end point model for DEX in pregnant sheep. We considered the competitive effect of cortisol (Cort) and DEX binding with glucocorticoid receptor and then used the indirect response model to describe disaturated-phosphatidylcholine (DSPC) dynamics. Based on that, we established a regression relationship between DSPC and fetal lung volume (V40). We then extrapolated the PD/end point model of pregnant sheep to pregnant monkeys by corrected stages of morphologic lung maturation in two species. Finally, we utilized the interspecies extrapolation strategy to simulate fetal exposure (AUC0-48h) and V40 relationship in pregnant women. The current model could well describe the maternal-fetal PK of DEX in pregnant animals. Simulated DEX AUC0-24h values of the umbilical venous to maternal plasma ratio in pregnant sheep and monkeys were 0.31 and 0.27, respectively. The simulated Cort curve and V40 in pregnant sheep closely matched the observed data within a 2-fold range. For pregnant monkeys, model-simulated V40 were well fitted with external verification data, which showed good interspecies extrapolation performance. Finally, we simulated fetal exposure-response relationship in pregnant women, which indicated that the fetal AUC0-48h of DEX should not be less than 300 and 100 ng/mL·hr at GW28 and GW34 to ensure fetal lung maturity. The current model preliminarily provided support for clinical DEX dose optimization.

Relationship between maternal arterial and foetal cord carbon dioxide tension and neonatal outcome in critically ill pregnant women at delivery.

No studies have evaluated the relationship between maternal arterial partial pressure of carbon dioxide (mPaCO2) and umbilical cord venous partial pressure of carbon dioxide (PCO2) in critically ill pregnant women at delivery. Based on the studies in healthy pregnant women, an mPaCO2 target of ≤50 mmHg is a suggested threshold during mechanical ventilation in critically ill parturients. We evaluated the relationship between mPaCO2 and neonatal cord gases in critically ill parturients at delivery as the primary objective. The relationship between mPaCO2 and APGAR scores at delivery was also analysed as a secondary objective. Maternal and neonatal cord gas data at delivery and APGAR scores were obtained by a retrospective chart review of 25 consecutive parturients with severe respiratory compromise who were delivered during mechanical ventilation. Linear regression was used to assess the relationship between mPaCO2 and umbilical artery and vein PCO2 and between mPaCO2 and APGAR scores at 1 and 5 min. There was a positive correlation between mPaCO2 and neonatal cord venous PCO2 (P = 0.013). Foetal venous PCO2 exceeded predelivery mPaCO2 by 17.5 (7.5) mmHg. There was an inverse relationship between mPaCO2 and neonatal APGAR scores at 1 and 5 min (P = 0.006 and P = 0.007, respectively). Foetal cord venous PCO2 can be predicted if mPaCO2 values are known. Unlike in healthy pregnant women, there was an inverse relationship between rising mPaCO2 levels and neonatal APGAR scores in critically ill pregnant women who had several associated compounding factors.

Association of free maternal and fetal ropivacaine after epidural analgesia for intrapartum caesarean delivery: a prospective observational trial

BackgroundRopivacaine is present in plasma in both protein-bound and free forms. The free form is responsible for the occurrence of toxic side effects. During obstetric epidural analgesia, free ropivacaine enters the fetal circulation depending on various factors. The aim of this study was to analyse a potential association between ropivacaine concentrations in maternal and fetal plasma and hence the extent of fetal exposure to ropivacaine. MethodsIn this prospective monocentre study, parturients who met the following criteria were included in the study: 1. epidural administration as part of obstetric anaesthesia, and 2. subsequent intrapartum caesarean delivery, which 3. was performed after an epidural bolus administration of ropivacaine within the existing epidural analgesia. Total and free ropivacaine concentrations were analysed in maternal blood at baseline, prior to epidural bolus administration for caesarean delivery, and in maternal and fetal (umbilical venous, oxygenated) blood at delivery. The results are presented as mean ± SD or median (25/75th percentile). ResultsWe screened 128 parturients who went into labour at term and requested epidural analgesia, of whom 39 were ultimately included in the study. An intrapartum caesarean delivery was performed after the epidural application of 207 (166/276) mg ropivacaine during an epidural treatment period of 577 (360/1010) min. Total and free ropivacaine concentrations were 1402 ± 357 ng/ml and 53 ± 46 ng/ml, respectively, in maternal venous blood and 457 ± 243 ng/ml and 43 ± 27 ng/ml, respectively, in fetal blood. The maternal total and free ropivacaine concentrations were significantly correlated (r = 0.873; P < 0.0001). ConclusionThe results of the present study suggest that determining the concentration of free ropivacaine in maternal blood may be a feasible option for estimating neonatal exposure to ropivacaine.

Successful Prediction of Fetal Exposure to Dual BCRP/P-gp Drug Substrates Using the Efflux Ratio-Relative Expression Factor Approach and PBPK M&S.

To inform fetal drug safety, it is important to determine or predict fetal drug exposure throughout pregnancy. The former is not possible in the first or second trimester. In contrast, at the time of birth, fetal drug exposure, relative to maternal exposure, can be estimated as Kp,uu (unbound fetal umbilical venous (UV) plasma area under the curve (AUC)/unbound maternal plasma (MP) AUC), provided the observed UV/MP values, spanning the dosing interval, are available from multiple maternal-fetal dyads. However, this fetal Kp,uu cannot be extrapolated to other drugs. To overcome the above limitations, we have used an efflux ratio-relative expression factor (ER-REF) approach to successfully predict the fetal Kp,uu of P-gp substrates. Because many drugs taken by pregnant people are also BCRP substrates, here, we extend this approach to drugs that are effluxed by both placental BCRP and P-gp or P-gp alone. To verify our predictions, we chose drugs for which UV/MP data were available at term: glyburide and imatinib (both BCRP and P-gp substrates) and nelfinavir (only P-gp substrate). First, the ER of the drugs was determined using Transwells and MDCKII cells expressing either BCRP or P-gp. Then, the ER was scaled using the proteomics-informed REF value to predict the fetal Kp,uu of the drug at term. The ER-REF predicted fetal Kp,uu of glyburide (0.43), imatinib (0.42), and nelfinavir (0.40) fell within two-fold of the corresponding in vivo fetal Kp,uu (0.44, 0.37, and 0.46, respectively). These data confirm that the ER-REF approach can successfully predict fetal drug exposure to BCRP/P-gp and P-gp substrates, at term.

Dwell time and bloodstream infection incidence of umbilical venous catheterization in China.

Central line-associated bloodstream infection (CLABSI) is one of the most serious complications of central venous access devices. Reducing the risk of CLABSI is of utmost significance in efforts to improve neonatal mortality rates and enhance long-term prognosis. To determine the dwell time and incidence of CLABSI of umbilical venous catheterization (UVC) for preterm infants in China. Preterm infants with UVC admitted to 44 tertiary neonatal intensive care units in 24 provinces in China were enrolled. Study period was from November 2019 to August 2021. The end point of observations was 48h after umbilical venous (UV) catheter removal. The primary outcomes were dwell time of UV catheter and UVC-associated CLABSI. Data between infants with UV catheter dwell time ≤7 days and >7 days, and with birth weight (BW) ≤1000g and >1000g were compared. In total, 2172 neonates were enrolled (gestational age 30.0±2.4 weeks, BW 1258.5±392.8g). The median UV catheter dwell time was 7 (6-10) days. The incidence of UVC-associated CLABSI was 3.03/1000 UV catheter days. For infants with UV catheter dwell time ≤7 days and >7 days, the UVC-associated CLABSI incidence was 3.71 and 2.65 per 1000 UV catheter days, respectively, P=0.23. For infants with UVC dwell times of 3-6, 7-12, and 13-15 days, the UVC-associated CLABSI rates were 0.14%, 0.68%, and 2.48% (P<0.01). The Kaplan-Meier plot of UV catheter dwell time to CLABSI showed no difference between infants with BW ≤1000g and >1000g (P=0.60). The median dwell time of UV catheter was 7 days, and the incidence of UVC-associated CLABSI was 3.03/1000 catheter days in China. The daily risk of UVC-associated CLABSI and other complications increased with the dwell time.

Indications, Measurements, and Complications of Ten Essential Neonatal Procedures.

About 10% of newborns require some degree of assistance to begin their breathing, and 1% necessitates extensive resuscitation. Sick neonates are exposed to a number of invasive life-saving procedures as part of their management, either for investigation or for treatment. In order to support the neonates with the maximum possible benefits and reduce iatrogenic morbidity, health-care providers performing these procedures must be familiar with their indications, measurements, and potential complications. Hence, the aim of this review is to summarise ten of the main neonatal intensive care procedures with highlighting of their indications, measurements, and complications. They include the umbilical venous and arterial catheterizations and the intraosseous line which represent the principal postnatal emergency vascular accesses; the peripherally inserted central catheter for long-term venous access; the endotracheal tube and laryngeal mask airway for airway control and ventilation; chest tube for drainage of air and fluid from the thorax; and the nasogastric/orogastric tube for enteral feeding. Furthermore, lumber puncture and heel stick were included in this review as very important and frequently performed diagnostic procedures in the neonatal intensive care unit.

Anesthetic drug concentrations and placental transfer rate in fetus between term and preterm infants, twins, and singletons.

Objective: This study aims to determine the drug concentration of etomidate, remifentanil, and rocuronium bromide for general anesthesia in fetus as well as the placental transport rate between term and preterm delivery, twins, and singleton. Study design: Sixty parturients with 72 fetuses undergoing cesarean section under general anesthesia were included. According to whether the fetus was a twin or premature, parturients were divided into Group I (term singleton), Group II (premature singleton), Group III (term twins), and Group IV (premature twins). The preoperative demographic characteristics and laboratory examination of parturients, hemodynamic indicators, the Apgar score of neonates at 1, 5, and 10min after delivery and at specific assigned values, umbilical artery blood gas analysis results, neonatal weight, and resuscitative measures were recorded. Anesthetic drug concentrations in maternal arterial (MA), umbilical arterial (UA), and umbilical venous (UV) blood were detected by Ultra Performance Liquid Chromatography Tandem Mass Spectrometry (UPLC-MS/MS). Result: No significant differences were observed in the concentrations of etomidate, remifentanil, and rocuronium bromide in MA, UV, and UA blood, or in the UV/MA and UA/UV ratios between term and preterm infants, twins, and singletons. Moreover, there was no variation in the anesthetic drug concentration among each pair of twins. Additionally, no correlation was found between the neonatal weight and the plasma concentrations of anesthetic drugs in UV and UA blood, except for remifentanil in UA blood. Conclusion: Preterm or twin deliveries do not affect the neonatal concentration of etomidate, remifentanil, and rocuronium bromide used in general anesthesia for cesarean sections. Clinical Trial Registration: www.chictr.org.cn, identifier ChiCTR2100046547.

Steps to improve umbilical vein catheterization in neonatal care

IntroductionIn neonatal units, umbilical vessel catheterization is the preferred method to gain vascular access in the initial management of the newborn because it is quick and easy.The failure rate ranges from to 50%, as the catheter can be found in the portal system in up to 40% of cases, leading to complications. This failure rate warrants the investigation of different methods to reduce the frequency of catheter malposition. We describe different techniques to improve the success rate in umbilical vein catheterization, such as the double catheter technique, positioning the newborn in right lateral decubitus for insertion, liver compression, and ultrasound-guided catheter insertion. The primary objective of the study was to assess the impact of new techniques on the success rate of central umbilical venous catheterization. Material and methodsPre- and post-intervention quasi-experimental study in a level B NICU conducted in January-June 2022 (pre-intervention) and July-December 2022 (post-intervention). ResultsPrior to the introduction of these new catheterization techniques, the failure rate of blind umbilical catheter insertion was 52%. Since the introduction of these measures, the overall failure rate has decreased to 27%. ConclusionsAfter the introduction of the new catheterization and recanalization methods, our success rate in umbilical vein catheterization has increased, and we believe it is necessary to implement them in units with similar failure rates to ours.

Fetal Oxygenation from the 23rd to the 36th Week of Gestation Evaluated through the Umbilical Cord Blood Gas Analysis.

The embryo and fetus grow in a hypoxic environment. Intrauterine oxygen levels fluctuate throughout the pregnancy, allowing the oxygen to modulate apparently contradictory functions, such as the expansion of stemness but also differentiation. We have recently demonstrated that in the last weeks of pregnancy, oxygenation progressively increases, but the trend of oxygen levels during the previous weeks remains to be clarified. In the present retrospective study, umbilical venous and arterial oxygen levels, fetal oxygen extraction, oxygen content, CO2, and lactate were evaluated in a cohort of healthy newborns with gestational age < 37 weeks. A progressive decrease in pO2 levels associated with a concomitant increase in pCO2 and reduction in pH has been observed starting from the 23rd week until approximately the 33-34th week of gestation. Over this period, despite the increased hypoxemia, oxygen content remains stable thanks to increasing hemoglobin concentration, which allows the fetus to become more hypoxemic but not more hypoxic. Starting from the 33-34th week, fetal oxygenation increases and ideally continues following the trend recently described in term fetuses. The present study confirms that oxygenation during intrauterine life continues to vary even after placenta development, showing a clear biphasic trend. Fetuses, in fact, from mid-gestation to near-term, become progressively more hypoxemic. However, starting from the 33-34th week, oxygenation progressively increases until birth. In this regard, our data suggest that the placenta is the hub that ensures this variable oxygen availability to the fetus, and we speculate that this biphasic trend is functional for the promotion, in specific tissues and at specific times, of stemness and intrauterine differentiation.

Neonatal Catheter and Tube Placement and Radiographic Assessment Statistics in Relation to Important Anatomic Landmarks.

Neonatal catheters and tubes are commonly used for monitoring and support for intensive care and must be correctly positioned to avoid complications. Position assessment is routinely done by radiography. The objective of this study is to characterize neonatal catheter and tube placement in terms of the proportion of those devices that are malpositioned. Using an institutional dataset of 723 chest/abdominal radiographs of neonatal intensive care unit (ICU) patients (all within 60 days of birth), we assessed the proportion of catheters that are malpositioned. Many radiographs contained multiple catheter types. Umbilical venous catheters (UVCs; 448 radiographs), umbilical arterial catheters (UACs; 259 radiographs), endotracheal tubes (ETTs; 451 radiographs), and nasogastric tubes (NGTs; 603 radiographs) were included in our analysis. UVCs were malpositioned in 90% of radiographs, while UACs were malpositioned in 36%, ETTs in 30%, and NGTs in just 5%. The most common locations in which UVCs were malpositioned were in the right atrium (31%) and umbilical vein (21%), and for UACs the most common malpositioned tip location was the aortic arch (8%). For the remaining tubes, 5% of ETTs were found to be in the right main bronchus and 4% of NGTs were found in the esophagus. A substantial proportion of catheters and tubes are malpositioned, suggesting that optimizing methods of catheter placement and assessment ought to be areas of focus for future work. · Neonatal catheters are frequently malpositioned.. · Most umbilical venous catheters need readjustment.. · X-ray and ultrasound are important for assessment.. · Catheter tips should be assessed in all X-rays..

Pasos para la mejora en la canalización umbilical en neonatología

IntroductionIn neonatal units, umbilical vessel catheterization is the preferred method to gain vascular access in the initial management of the newborn because it is quick and easy. The failure rate ranges from 25% to 50%, as the catheter can be found in the portal system in up to 40% of cases, leading to complications. This failure rate warrants the investigation of different methods to reduce the frequency of catheter malposition. We describe different techniques to improve the success rate in umbilical vein catheterization, such as the double catheter technique, positioning the newborn in right lateral decubitus for insertion, liver compression, and ultrasound-guided catheter insertion. The primary objective of the study was to assess the impact of new techniques on the success rate of central umbilical venous catheterization. Material and methodsPre- and post-intervention quasi-experimental study in a level B NICU conducted in January to June 2022 (pre-intervention) and July to December 2022 (post-intervention). ResultsPrior to the introduction of these new catheterization techniques, the failure rate of blind umbilical catheter insertion was 52%. Since the introduction of these measures, the overall failure rate has decreased to 27%. ConclusionsAfter the introduction of the new catheterization and recanalization methods, our success rate in umbilical vein catheterization has increased, and we believe it is necessary to implement them in units with similar failure rates to ours.

Safety and feasibility of platelet transfusion through long catheters in the neonatal intensive care unit: an in vitro study

ObjectiveTo assess the safety and feasibility of platelet transfusion through small-bore long lines used in the neonatal intensive care unit (NICU), including double-lumen umbilical venous catheters (UVCs) and 24 G...

Intra-abdominal umbilical venous diameter and abdominal circumference discordance at 15-20weeks' gestation: simple markers in transverse abdominal plane to predict adverse pregnancy outcomes in monochorionic diamniotic twins.

This study aimed to investigate the association between simple markers in fetal abdominal plane, intra-abdominal umbilical venous diameter (DIUV) and abdominal circumference (AC) discordance at 15-20weeks' gestation, and adverse pregnancy outcomes in monochorionic diamniotic (MCDA) twins. We performed a retrospective analysis of MCDA twins with two live fetuses examined at 15-20weeks from Jun 2020 to Dec 2021 at Beijing Obstetrics and Gynecology Hospital. Measurement of fetal AC and DIUV was performed according to standard protocols. Twin pregnancies with major fetal structural anomalies, chromosomal abnormalities, miscarriage, and twin reversed arterial perfusion sequence were excluded. DIUV and AC discordance in MCDA twins with an adverse pregnancy outcome was compared with a normal pregnancy outcome. Furthermore, the performance of DIUV and AC discordance in predicting adverse pregnancy outcomes in MCDA twins was assessed. A total of 105 women with MCDA twin pregnancies were enrolled, contributing 179 visits. Adverse pregnancy outcomes occurred in 33.3% (35/105) of cases in our study. The intra-observer and inter-observer intraclass correlation coefficient (ICC) of both AC and DIUV were very good or excellent. There was no statistical difference in AC and DIUV discordance (%) between 15-16, 17-18, and 19-20weeks (χ2 = 3.928, P = 0.140; χ2 = 2.840, P = 0.242). Both AC and DIUV discordance were greater in twins with adverse pregnancy outcomes than that in twins with normal pregnancy outcome at each pregnancy periods. Both AC discordance (OR 1.2, 95% CI 1.1-1.3) and DIUV discordance (OR 1.2, 95% CI 1.1-1.2) were associated with adverse pregnancy outcomes. The AUC for predicting adverse pregnancy outcomes by AC discordance was 0.75 (95% CI 0.68-0.83), with a sensitivity of 58.7% (95% CI 51.9-64.5) and a specificity of 86.2% (95% CI 81.7-88.4). The AUC for predicting adverse pregnancy outcomes by DIUV was 0.78 (95% CI 0.70-0.86), with sensitivity and specificity of 65.1% (95% CI 58.1-70.3) and 86.2% (95% CI 81.7-88.4), respectively. The AC discordance and DIUV discordance could predict adverse pregnancy outcomes in MCDA twins. When these simple markers occurred, intensive surveillance was recommended.

The role of different Doppler parameters in predicting adverse neonatal outcomes in fetuses with late-onset fetal growth restriction.

The aim of this study is to clarify the role of different Doppler parameters such as umbilicocerebral ratio (UCR), cerebroplacentouterine ratio (CPUR), aortic isthmus, renal artery, and umbilical vein flow Doppler in predicting adverse neonatal outcomes in fetuses with late -onset fetal growth restriction. The study included all patients diagnosed with fetal growth restriction at 32-39 weeks' gestation between 01/02/2020 and 01/02/2022 and treated at the Department of Obstetrics and Gynecology, Inonu University School of Medicine. Patients included in the study had a median gestational week at delivery of 37 (minimum 33+0-maximum 39+0), median CPR of 1.42 (minimum-maximum 0.43-3.57), and median UCR of 0.7 (minimum-maximum 0.28-2.3). Receiver operating characteristic analysis was performed to determine the performance of the measured obstetric Doppler parameters in predicting the development of adverse neonatal outcomes. Umbilical venous blood flow showed the best performance in predicting adverse neonatal outcomes [area under the curve 0.952, 95% confidence interval (CI) 0.902-0.981, p<0.001]. Multivariate logistic regression analysis showed that fetuses with abnormal CPUR had a 4.5-fold (95% CI 0.084-0.583, p=0.02) increased risk of adverse neonatal outcome, whereas fetuses with abnormal umbilical venous flow had a 1.07-fold (95% CI 0.903-0.968, p<0.001) increased risk of adverse neonatal outcome. The results of this study demonstrate that the use of UCR, CPUR, umbilical venous flow, and aortic isthmus PI Doppler parameters along with umbilical artery PI and CPR are effective in predicting adverse neonatal outcomes in fetuses with late -onset fetal growth restriction.

Extra-hepatic portal vein obstruction leading to portal cavernoma cholangiopathy without liver dysfunction

In adults, EHPVO mainly occurs following thrombosis, while in children it may be related to congenital malformations and/or neonatal umbilical venous catheterization. EHPVO leads to the cavernous transformation of the portal vein in the absence of recanalization. Portal cholangiopathy (also referred to as portal biliopathy) is common in patients with long-standing chronic PVT. It is due to compression of the large bile ducts by the venous collaterals (portal cavernoma) that form in patients with chronic PVT. Typically, symptoms of portal cholangiopathy include jaundice, biliary colic and pruritus.

Association of Umbilical Cord Blood Gas Values With Mortality and Severe Neurologic Injury in Preterm Neonates &lt;29 Weeks’ Gestation: A National Cohort Study

(Am J Obstet Gynecol. 2022;227:85.e1–10) The acid-base status of a neonate at the time of birth is determined through analysis of umbilical cord blood gas values. Deranged umbilical cord arterial (UA) and umbilical cord venous (UV) blood gas values can be linked to poor neonatal outcomes. Previous studies have found an association between a UA or UV pH value of &lt;7.0 and neonatal mortality. However, the relationship between umbilical cord blood gas values and adverse outcomes, specifically in preterm neonates born before 29 weeks gestation, is not clear. This study aimed to explore the association between umbilical cord blood gas values with neonatal mortality and severe neurological injury (SNI) in infants born before 29 weeks gestation.

Ultrasound measurement of umbilical venous flow volume at the intra-abdominal portion in normal fetuses

PurposeUmbilical venous flow volume (UVFV) measured using ultrasound can be used to assess placental circulation in a fetus. UVFV measured at the intra-abdominal portion using half the maximum flow velocity of the umbilical vein (UV) has good reproducibility with low variance. However, reference values in previous reports were based on a small number of cases with a wide reference range. In the present study, we evaluated UVFV standard values measured at the intra-abdominal portion in normal Japanese fetuses.MethodsMeasurements were performed on normal pregnant women during routine ultrasound screening at around 20 or 30 weeks of gestation. The diameter and flow velocity of the UV were measured at the fetal abdomen point between the insertion of the UV and branches of the portal vein. UVFV (ml/min) was calculated as follows: (UV diameter [cm]/2)2 × maximum velocity [cm/s] × 0.5 × 3.14 × 60).ResultsA total of 278 pregnant women were included in the study. UVFV increased with gestational weeks, and UVFV per estimated fetal weight (EFW) slightly decreased with increasing gestational weeks. The 50th (10th–90th) percentiles of UVFV per EFW at 20, 25, and 30 weeks of gestation were 130 (105–165), 123 (94–147), and 104 (80–131) ml/min/kg, respectively.ConclusionNew UVFV reference values measured at the intra-abdominal portion of fetuses using large-scale samples were established. Future studies should assess fetuses under pathologic conditions using UVFV reference values.

Prolonged Anesthesia Induction to Delivery Time Did Not Influence Plasma Remifentanil Concentration in Neonates.

Remifentanil, in combination with etomidate and sevoflurane, is commonly used in clinics for general anesthesia induction in cesarean section (CS). This study aimed to evaluate the correlation between the induction to delivery (I-D) time and neonatal plasma drug concentration and anesthesia, as well as its effects on neonates. Fifty-two parturients in whom general anesthesia was induced for CS were divided into group A (I-D<8 min) and group B (I-D≥8 min). Maternal arterial (MA), umbilical venous (UV), and umbilical arterial (UA) blood samples were collected at delivery to analyze the remifentanil and etomidate concentrations using liquid chromatography-tandem mass spectrometry. There were no statistically significant differences between the two groups in terms of plasma concentrations of remifentanil in the MA, UA, and UV blood (P > 0.05). The plasma concentration of etomidate in MA and UV was higher in group A than that in group B (P<0.05), whereas the UA/UV ratio of etomidate was higher in group B than that in group A (P<0.05). The Spearman rank correlation test showed no correlation between the I-D time and plasma remifentanil concentration in the MA, UA, and UV plasma (P>0.05). The concentrations of etomidate in the MA and UV were negatively correlated with the I-D time (P < 0.05). Prolonged I-D time did not significantly influence the maternal or neonatal plasma concentration of remifentanil. It is safe to administer remifentanil target-controlled infusion in combination with etomidate and sevoflurane for general anesthesia induction during CS.

Fetal oxygenation in the last weeks of pregnancy evaluated through the umbilical cord blood gas analysis.

Embryo and fetus grow and mature over the first trimester of pregnancy in a dynamic hypoxic environment, where placenta development assures an increased oxygen availability. However, it is unclear whether and how oxygenation changes in the later trimesters and, more specifically, in the last weeks of pregnancy. Observational study that evaluated the gas analysis of the umbilical cord blood collected from a cohort of healthy newborns with gestational age ≥37 weeks. Umbilical venous and arterial oxygen levels as well as fetal oxygen extraction were calculated to establish whether oxygenation level changes over the last weeks of pregnancy. In addition, fetal lactate, and carbon dioxide production were analyzed to establish whether oxygen oscillations may induce metabolic effects in utero. This study demonstrates a progressive increase in fetal oxygenation levels from the 37th to the 41st weeks of gestation (mean venous PaO2 approximately from 20 to 25 mmHg; p < 0.001). This increase is largely attributable to growing umbilical venous PaO2, regardless of delivery modalities. In neonates born by vaginal delivery, the increased oxygen availability is associated with a modest increase in oxygen extraction, while in neonates born by cesarean section, it is associated with reduced lactate production. Independently from the type of delivery, carbon dioxide production moderately increased. These findings suggest a progressive shift from a prevalent anaerobic metabolism (Warburg effect) towards a growing aerobic metabolism. This study confirms that fetuses grow in a hypoxic environment that becomes progressively less hypoxic in the last weeks of gestation. The increased oxygen availability seems to favor aerobic metabolic shift during the last weeks of intrauterine life; we hypothesize that this environmental change may have implications for fetal maturation during intrauterine life.