Bacterial DNA detection in very preterm infants assessed for risk of early onset sepsis

Objectives The aim of this study is to evaluate the diagnostic ability of multiplex real-time polymerase chain reaction (PCR) in very preterm infants assessed for risk of early onset neonatal sepsis (EOS). Methods Prospective observational cohort study. Blood samples of preterm neonates ≤32 weeks of gestation were evaluated by commercial multiplex real-time PCR within 2 h after delivery. The definition of EOS was based on positive blood culture and clinical signs of infection or negative blood culture, clinical signs of infection and abnormal neonatal blood count and serum biomarkers. Results Among 82 subjects analyzed in the study, 15 had clinical or confirmed EOS. PCR was positive in four of these infants (including the only one with a positive blood culture), as well as in 15 of the 67 infants without sepsis (sensitivity 27%, specificity 78%). Out of 19 PCR positive subjects, Escherichia coli was detected in 12 infants (63%). Statistically significant association was found between vaginal E. coli colonization of the mother and E. coli PCR positivity of the neonate (p=0.001). No relationship was found between neonatal E. coli swab results and assessment findings of bacterial DNA in neonatal blood stream. Conclusions Multiplex real-time PCR had insufficient diagnostic capability for EOS in high risk very preterm infants. The study revealed no significant association between PCR results and the diagnosis of clinical EOS. Correlation between maternal vaginal swab results and positive PCR in the newborn needs further investigation to fully understand the role of bacterial DNA analysis in preterm infants.

The Effect of Platelets on Thrombin Generation in Cord Blood and Peripheral Neonatal Blood in the Premature Infant; The Event Study

Introduction Infants born very preterm (<32 weeks) are at increased risk of haemorrhage, particularly intraventricular haemorrhage which can result in short and long term morbidity. Routine clinical laboratory tests such as the prothrombin time and activated partial thromboplastin time are frequently abnormal in this patient group but do not appear to correlate with clinical outcomes. Moreover, while reduced levels of circulating coagulation factors and platelet hypo-reactivity have been reported, plasma thrombin generation (TG), has been reported to be similar or even enhanced in very preterm infants when compared to term infants. Extracellular vesicles, comprising of lipid-bound nanoparticles released from cells (including platelets), may potentially play a role in modulating neonatal haemostasis. We aimed to characterize phospholipid (PL)-dependent plasma thrombin generation in platelet-rich (PRP) and platelet-poor plasma (PPP) in premature infants in both umbilical cord blood & peripheral neonatal blood using calibrated automated thrombography (CAT). Methods In this prospective observational study, PRP and PPP was prepared by centrifugation from citrated umbilical cord blood and peripheral neonatal blood collected from premature infants (24 - 31 weeks) and healthy term controls (>37 weeks). No samples were collected from heparinised lines. Parameters of plasma thrombin generation in PRP were assessed using CAT, with thrombin generation stimulated by tissue factor only (TF; final concentration 1pM). CAT was also repeated in PPP using only TF and no exogenous PL (rendering the assay dependent upon the endogenous PL content of plasma). Results In the analysis of umbilical cord blood PRP, plasma thrombin generation was accelerated in the preterm infant group with a significantly shorter time to peak TG observed. The other parameters of TG were similar in both groups (Table 1). In the subset of infants from whom peripheral blood samples were available, there was further evidence of enhanced plasma TG in preterm PRP relative to term infants (Table 2). In this subgroup, the lag time and time to peak thrombin were significantly shorter in the preterm group and peak thrombin was significantly higher. TG was also assessed in both PPP and PRP prepared from umbilical cord blood samples in a subgroup of infants (n=10 term, n=6 preterm) using 1pM TF only, rendering the assay dependent on the phospholipid content of plasma. No difference was observed in any CAT parameters, suggesting that neonatal PPP phospholipid content (potentially from circulating extracellular vesicles) is sufficient to support thrombin generation in the absence of exogenous phospholipid. Conclusion These preliminary data suggest that neonatal PRP, measured in both umbilical cord blood and peripheral neonatal blood, has similar thrombin generation or may even be hypercoagulable, compared with healthy term controls. Moreover, neonatal plasma phospholipid appears to support thrombin generation in the absence of exogenous phospholipid. This ongoing prospective study aims to further characterize the platelet-dependency of neonatal thrombin generation and evaluate the potential role of extracellular vesicles in neonatal haemostasis. Figure 1 Figure 1. Disclosures Maguire: Actelion: Research Funding; Bayer Pharma: Research Funding. Ni Ainle: Leo Pharma: Research Funding; Actelion: Research Funding; Daiichi-Sankyo: Research Funding; Bayer Pharma: Research Funding.

Retrospective Cohort Study of Neonatal Blood Transfusion in China

Background: Blood transfusion treatment is extremely important for newborns，but the threshold of neonatal blood transfusion is not same in different countries, which may be due to differences in regions, races and nationalities, as well as medical conditions and treatment methods. Up to now, there are not enough clinical studies and prospective follow-up to determine the suitable threshold for Chinese newborns. Therefore, it is important to establish a retrospective and prospective multicenter cohort study to evaluate whether the blood transfusion scheme is suitable for newborns in China.Methods: This is a retrospective cohort study of neonatal blood transfusion and prospective follow-up from January 1, 2017 to June 30, 2021, aim to evaluate the effect of restricted and unrestricted blood transfusion on neonatal health. Diagnosis and blood transfusion data of 5,669 newborns between January 1, 2017 and June 30, 2018 from 46 hospitals in China were analyzed through retrospective study and followed up for 1w,1m and 3y after discharge. The variable data of newborns and their mothers was collected in this cohort study with 280 variables and 2.98 million data volumes including in the database. The primary outcome index of the study was death, and the secondary outcome index was complications during hospitalization, hospitalization time, NICU hospitalization days and hospitalization expenses.Discussion: The groups were grouped by birth weight, and each group was defined as a restricted and unrestricted cohort according to the Recommended Program for Neonatal Blood Transfusion (5th Edition), and evaluate applicability of this scheme for Chinese newborns based on outcome indicators. According to the neonatal treatment data, a appropriate neonatal blood transfusion threshold and neonatal blood transfusion program for China would be determined.

Antenatal and perinatal factors influencing neonatal blood pressure: a systematic review

Objective A comprehensive understanding of the factors contributing to perinatal blood pressure is vital to ensure optimal postnatal hemodynamic support. The objective of this study was to review existing literature on maternal and perinatal factors influencing blood pressure in neonates up to 3 months corrected age. Methods A systematic search of published literature in OVID Medline, OVID Embase and the COCHRANE library identified publications relating to maternal factors affecting blood pressure of neonates up to corrected age of 3 months. Summary data were extracted and compared (PROSPERO CRD42018092886). Results Of the 3683 non-duplicate publications identified, 44 were eligible for inclusion in this review. Topics elicited were sociodemographic factors, maternal health status, medications, smoking during pregnancy, and cord management at birth. Limited data were available for each factor. Results regarding the impact of these factors on neonatal blood pressure were inconsistent across studies. Conclusions There is insufficient evidence to draw definitive conclusions regarding the impact of various maternal and perinatal factors on neonatal blood pressure. Future investigations of neonatal cardiovascular therapies should account for these factors in their study design. Similarly, studies on maternal diseases and perinatal interventions should include neonatal blood pressure as part of their primary or secondary analyses.

Mechanisms underlying neonate specific metabolic effects of volatile anesthetics

Volatile anesthetics (VAs) are widely used in medicine, but the mechanisms underlying their effects remain ill-defined. Though routine anesthesia is safe in healthy individuals, instances of sensitivity are well-documented, and there has been significant concern regarding the impact of VAs on neonatal brain development. Evidence indicates that VAs have multiple targets, with anesthetic and non-anesthetic effects mediated by neuroreceptors, ion channels, and the mitochondrial electron transport chain. Here, we characterize an unexpected metabolic effect of VAs in neonatal mice. Neonatal blood β-hydroxybutarate (β-HB) is rapidly depleted by VAs at concentrations well below those necessary for anesthesia. β-HB in adults, including animals in dietary ketosis, is unaffected. Depletion of β-HB is mediated by citrate accumulation, malonyl-CoA production by acetyl-CoA carboxylase, and inhibition of fatty acid oxidation. Adults show similar significant changes to citrate and malonyl-CoA, but are insensitive to malonyl-CoA, displaying reduced metabolic flexibility compared to younger animals.

A study of effect of delayed and early umbilical cord clamping on neonatal haemoglobin status

Background: Delayed cord clamping has been supported by physician because it allows for physiological transfer of blood from placenta to the infant and thus permits placenta to newborn transfusion and results in an increased neonatal blood volume at birth. At present there is no standard definition of delayed cord clamping. Clamping time varies significantly between studies and a wide range of parameters were used for clamping of cord.Methods: This was an observational study conducted in a public hospital among 200 uncomplicated full-term pregnancies where 100 each were present in early cord clamping (ECC) and delayed cord clamping (DCC) groups respectively and neonatal haematological parameters studied according to different cord clamping times.Results: There was a significant increase of mean haemoglobin level from 14.8 to 16.0 g/dl from 15 secs to 60 secs and gradual increase of mean haemoglobin level from 16.2 to 16.8 g/dl from 60 secs to 180 secs. There was a highly significant difference between ECC and DCC groups regarding mean haemoglobin level and MCH values. MCV and MCH values were also significantly different in both the groups.Conclusions: We concluded in this study that delayed cord clamping, resulted in improved haemoglobin and other haematocrit levels specially when cord was clamped after first 60 secs. Delayed clamping also reduced the prevalence of neonatal anaemia at 2 days of age. In terms of maternal outcomes, delayed umbilical cord clamping did not increase the risk of postpartum haemorrhage or the need for blood transfusion.

Maternal Blood Group and Routine Direct Antiglobulin Testing in Neonates: Is There a Role for Selective Neonatal Testing?

Recommendations for the screening of hemolytic disease of the newborn (HDN) advise taking a selective approach in using the direct antiglobulin test (DAT) for mothers with blood group O or RhD-negative. This study assessed the relation of DAT results to maternal and neonatal blood groups and evaluated the risk of HDN. A retrospective analysis of all healthy newborns admitted during 2018 was performed. Of 1463 newborns, 4.4% had a positive DAT. There were 541 (37%) maternal–neonatal pairs with ABO incompatibility, most commonly born to mothers with blood group O. The cohort of neonates born to mothers with blood group O was divided into three groups: the O-A and O-B groups and the O-O group as a control. The DAT was positive in 59 (8.3%) neonates; most were in the O-B group (49.2%), whereas 13.6% were in the control group (p < 0.01). While the neonates in the O-B group were more likely to require phototherapy (p = 0.03), this finding was not related to DAT results. We found that selective testing of mothers with blood group O, mothers with blood group O or RhD-negative, neonates with blood group B, and neonates with blood group B born to mothers with blood group O or RhD-negative was ineffective in detecting phototherapy requirements. Our results indicate no difference regarding the need for phototherapy in neonates born to mothers with different blood types regardless of the DAT results.

Current State of Knowledge about Transplacental Transmission of SARS-CoV-2 Infection

Background: To date, some cases of perinatal transmission of severe acute respiratory syndrome coronavirus-2 (SARS‐CoV‐2) have been reported. However, it is unanswered if these occurred via the trans-placental or the trans-cervical route or through environmental exposure. Methods: To address this question, we conducted this study to review the current state of knowledge about the transplacental transmission of COVID-19. Results: There are no known placental findings associated with the COVID-19 infection. The possibility of intrauterine infection has been based mainly on the detection of IgM in the neonatal blood. Real time-PCR tests on amniotic fluid, placenta, and cord blood are required to ascertain the possibility of intrauterine vertical transmission. Conclusion: There is currently no sufficient and convincing evidence about the transplacental transmission of SARS-COV-2 infection in pregnant mothers. However, the paucity of placental expression of ACE-2 involved in the cytoplasmic entry of SARS-CoV-2 may explain its relative insensitivity to transplacental infection.