Correction: Nerdrum Aagaard et al. Significance of Neonatal Heart Rate in the Delivery Room-A Review. Children, 10, 1551

In the original publication [...].

Significance of Neonatal Heart Rate in the Delivery Room-A Review

BACKGROUND

Heart rate (HR) is considered the main vital sign in newborns during perinatal transition, with a threshold of 100 beats per minute (bpm), below which, intervention is recommended. However, recent changes in delivery room management, including delayed cord clamping, are likely to have influenced normal HR transition.

OBJECTIVE

To summarize the updated knowledge about the factors, including measurement methods, that influence HR in newborn infants immediately after birth. Additionally, this paper provides an overview of delivery room HR as a prognostic indicator in different subgroups of newborns.

METHODS

We searched PubMed, EMBASE, and Google Scholar with the terms infant, heart rate, delivery room, resuscitation, pulse oximetry, and electrocardiogram.

RESULTS

Seven studies that described HR values in newborn infants immediately after birth were included. Pulse oximetry-derived HR percentiles after immediate cord clamping may not be applicable to the current practice of delayed cord clamping and the increasing use of delivery room electrocardiograms. Mask ventilation may adversely affect HR, particularly in premature and non-asphyxiated infants. Prolonged bradycardia is a negative prognostic factor, especially if combined with hypoxemia in infants <32 weeks of gestation.

CONCLUSIONS

HR assessment in the delivery room remains important. However, the cardiopulmonary transition is affected by delayed cord clamping, gestational age, and underlying conditions.

Extrauterine Growth Restriction: Need for an Accurate Definition

Neonates show considerable variation in growth that can be recognized through serial measurements of basic variables such as weight, length, and head circumference. If possible, measurement of subcutaneous and total body fat mass can also be useful. These biometric measurements at birth may be influenced by demographics, maternal and paternal anthropometrics, maternal metabolism, preconceptional nutritional status, and placental health. Subsequent growth may depend on optimal feeding, total caloric intake, total metabolic activity, genetic makeup, postnatal morbidities, medications, and environmental conditions. For premature infants, these factors become even more important; poor in utero growth can be an important reason for spontaneous or induced preterm delivery. Later, many infants who have had intrauterine growth restriction (IUGR) and are born small for gestational age (SGA) continue to show suboptimal growth below the 10th percentile, a condition that has been defined as extrauterine growth restriction (EUGR) or postnatal growth restriction (PNGR). More importantly, a subset of these growth-restricted infants may also be at high risk of abnormal neurodevelopmental outcomes. There is a need for well-defined criteria to recognize EUGR/PNGR, so that correctional steps can be instituted in a timely fashion.

Ending Preventable Neonatal Deaths: Multicountry Evidence to Inform Accelerated Progress to the Sustainable Development Goal by 2030

INTRODUCTION

The Sustainable Development Goal (SDG) 3.2 aims for every country to reach a neonatal mortality rate (NMR) of ≤12/1,000 live births by 2030. More than 60 countries are off track, and 2.3 million newborns still die each year. Urgent action is needed, but varies by context, notably mortality level.

METHODS

We applied a five-phase NMR transition model based on national analyses for 195 UN member states: I (NMR >45), II (30-<45), III (15-<30), IV (5-<15), and V (<5). We analyzed data over the last century from selected countries to inform strategies to reach SDG3.2. We also undertook impact analyses for packages of care using the Lives Saved Tool software.

RESULTS

An NMR of <15/1,000 requires firstly wide-scale access to maternity care and hospital care for small and sick newborns, including skilled nurses and doctors, safe oxygen use, and respiratory support, such as CPAP. Neonatal mortality could be reduced to the SDG target of ≤12/1,000 with further scale-up of small and sick newborn care. To reduce neonatal mortality further, more investment is required in infrastructure, device bundles (e.g., phototherapy, ventilation), and careful attention to infection prevention. To reach phase V (NMR <5), which is closer to ending preventable newborn deaths, additional technologies and therapies such as mechanical ventilation and surfactant replacement therapy are needed, as well as higher staffing ratios.

CONCLUSIONS

Learning from high-income country is important, including what not to do. Introduction of new technologies should be according to the country's phase. Early focus on disability-free survival and family involvement is also crucial.

Searching for Evidence in Neonatology

Evidence based medicine has changed clinical practice by incorporating data from randomized controlled trials (RCTs). While some biases in RCTs are well recognized, we discuss some less acknowledged. Selection bias may arise in the consent stage. Industry funded studies more often report a positive outcome. Post-hoc changes of outcome measures and other mis-reporting lowers the reliability of outcome data. Finally even the GRADE system retains subjectivity. CONCLUSION: Moving from "intuition" into "evidence based" medicine involves grappling with several pitfalls. These pose challenges for authors, editors, reviewers, and readers. All require vigilance before drawing conclusions from presented data.

Umbilical cord blood acid-base analysis at birth and long-term neurodevelopmental outcomes in children: a systematic review and meta-analysis

BACKGROUND

Umbilical cord blood acid-base sampling is routinely performed at many hospitals. Recent studies have questioned this practice and the association of acidosis with cerebral palsy.

OBJECTIVE

To investigate the associations between the results of umbilical cord blood acid-base analysis at birth and long-term neurodevelopmental outcomes and mortality in children.

SEARCH STRATEGY

We searched six databases using the search strategy: umbilical cord AND outcomes.

SELECTION CRITERIA

Randomised controlled trials, cohorts and case-control studies from high-income countries that investigated the association between umbilical cord blood analysis and neurodevelopmental outcomes and mortality from 1 year after birth in children born at term.

DATA COLLECTION AND ANALYSIS

We critically assessed the included studies, extracted data and conducted meta-analyses comparing adverse outcomes between children with and without acidosis, and the mean proportions of adverse outcomes. The certainty of evidence was assessed using the Grading of Recommendations, Assessment, Development and Evaluations approach.

MAIN RESULTS

We have very low confidence in the following findings: acidosis was associated with higher cognitive development scores compared with non-acidosis (mean difference 5.18, 95% CI 0.84-9.52; n = two studies). Children with acidosis also showed a tendency towards higher risk of death (relative risk [RR] 5.72, 95% CI 0.90-36.27; n = four studies) and CP (RR 3.40, 95% CI 0.86-13.39; n = four studies), although this was not statistically significant. The proportion of children with CP was 2.39/1000 across the studies, assessed as high certainty evidence.

CONCLUSION

Due to low certainty of evidence, the associations between umbilical cord blood gas analysis at delivery and long-term neurodevelopmental outcomes in children remains unclear.

Long Non-Coding RNAs in Hypoxia and Oxidative Stress: Novel Insights Investigating a Piglet Model of Perinatal Asphyxia

Birth asphyxia is the leading cause of death and disability in young children worldwide. Long non-coding RNAs (lncRNAs) may provide novel targets and intervention strategies due to their regulatory potential, as demonstrated in various diseases and conditions. We investigated cardinal lncRNAs involved in oxidative stress, hypoxia, apoptosis, and DNA damage using a piglet model of perinatal asphyxia. A total of 42 newborn piglets were randomized into 4 study arms: (1) hypoxia–normoxic reoxygenation, (2) hypoxia–3 min of hyperoxic reoxygenation, (3) hypoxia–30 min of hyperoxic reoxygenation, and (4) sham-operated controls. The expression of lncRNAs BDNF-AS, H19, MALAT1, ANRIL, TUG1, and PANDA, together with the related target genes VEGFA, BDNF, TP53, HIF1α, and TNFα, was assessed in the cortex, the hippocampus, the white matter, and the cerebellum using qPCR and Droplet Digital PCR. Exposure to hypoxia–reoxygenation significantly altered the transcription levels of BDNF-AS, H19, MALAT1, and ANRIL. BDNF-AS levels were significantly enhanced after both hypoxia and subsequent hyperoxic reoxygenation, 8% and 100% O2, respectively. Our observations suggest an emerging role for lncRNAs as part of the molecular response to hypoxia-induced damages during perinatal asphyxia. A better understanding of the regulatory properties of BDNF-AS and other lncRNAs may reveal novel targets and intervention strategies in the future.

Oxygenation of the newborn. The impact of one molecule on newborn lives

Hypoxanthine is a purine metabolite which increases during hypoxia and therefore is an indicator of this condition. Further, when hypoxanthine is oxidized to uric acid in the presence of xanthine oxidase, oxygen radicals are generated. This was the theoretical basis for suggesting and studying, beginning in the 1990s, resuscitation of newborn infants with air instead of the traditional 100% O2. These studies demonstrated a 30% reduction in mortality when resuscitation of term and near term infants was carried out with air compared to pure oxygen. The mechanism for this is not fully understood, however the hypoxanthine -xanthine oxidase system increases oxidative stress and plays a role in regulation of the perinatal circulation. Further, hyperoxic resuscitation inhibits mitochondrial function, and one reason may be that genes involved in ATP production are down-regulated. Thus, the study of one single molecule, hypoxanthine, has contributed to the global prevention of an estimated 2-500,000 annual infant deaths.

A Piglet Perinatal Asphyxia Model to Study Cardiac Injury and Hemodynamics after Cardiac Arrest, Resuscitation, and the Return of Spontaneous Circulation

Neonatal piglets have been extensively used as translational models for perinatal asphyxia. In 2007, we adapted a well-established piglet asphyxia model by introducing cardiac arrest. This enabled us to study the impact of severe asphyxia on key outcomes, including the time taken for the return of spontaneous circulation (ROSC), as well as the effect of chest compressions according to alternative protocols for cardiopulmonary resuscitation. Due to the anatomical and physiological similarities between piglets and human neonates, piglets serve as good models in studies of cardiopulmonary resuscitation and hemodynamic monitoring. In fact, this cardiac arrest model has provided evidence for guideline development through research on resuscitation protocols, pathophysiology, biomarkers, and novel methods for hemodynamic monitoring. Notably, the incidental finding that a substantial fraction of piglets have pulseless electrical activity (PEA) during cardiac arrest may increase the applicability of the model (i.e., it may be used to study pathophysiology extending beyond the perinatal period). However, the model generation is technically challenging and requires various skill sets, dedicated personnel, and a fine balance of the measures, including the surgical protocols and the use of sedatives/analgesics, to ensure a reasonable rate of survival. In this paper, the protocol is described in detail, as well as experiences with adaptations to the protocol over the years.

Microbial DNA extraction of high-host content and low biomass samples: Optimized protocol for nasopharynx metagenomic studies

Introduction

Low microbial biomass and high human DNA content in nasopharyngeal aspirate samples hinder comprehensive characterization of microbiota and resistome. We obtained samples from premature infants, a group with increased risk of developing respiratory disorders and infections, and consequently frequent exposure to antibiotics. Our aim was to devise an optimal protocol for handling nasopharyngeal aspirate samples from premature infants, focusing on host DNA depletion and microbiome and resistome characterization.

Methods

Three depletion and three DNA extraction protocols were compared, using RT-PCR and whole metagenome sequencing to determine the efficiency of human DNA removal, taxonomic profiling and assignment of antibiotic resistance genes. Protocols were tested using mock communities, as well as pooled and individual patient samples.

Results

The only extraction protocol to retrieve the expected DNA yield from mock community samples was based on a lytic method to improve Gram positive recovery (MasterPure™). Host DNA content in non-depleted aliquots from pooled patient samples was 99%. Only samples depleted with MolYsis™ showed satisfactory, but varied reduction in host DNA content, in both pooled and individual patient samples, allowing for microbiome and resistome characterisation (host DNA content from 15% to 98%). Other depletion protocols either retrieved too low total DNA yields, preventing further analysis, or failed to reduce host DNA content. By using Mol_MasterPure protocol on aliquots from pooled patient samples, we increased the number of bacterial reads by 7.6 to 1,725.8-fold compared to non-depleted reference samples. PCR results were indicative of achieved microbial enrichment. Individual patient samples processed with Mol_MasterPure protocol varied greatly in total DNA yield, host DNA content (from 40% to 98%), species and antibiotic resistance gene richness.

Discussion

Despite high human DNA and low microbial biomass content in nasopharynx aspirates of preterm infants, we were able to reduce host DNA content to levels compatible with downstream shotgun metagenomic analysis, including bacterial species identification and coverage of antibiotic resistance genes. Whole metagenomic sequencing of microbes colonizing the nasopharynx may contribute to explaining the possible role of airway microbiota in respiratory conditions and reveal carriage of antibiotic resistance genes.

Is the increasing prevalence of labor induction accompanied by changes in pregnancy outcomes? An observational study of all singleton births at gestational weeks 37-42 in Norway during 1999-2019

INTRODUCTION

Induction of labor is often performed to prevent adverse perinatal and maternal outcomes, and has become increasingly common. We studied whether changes in prevalence of labor induction in gestational weeks 37-42 weeks were accompanied by changes in adverse pregnancy outcomes or mode of delivery.

MATERIAL AND METHODS

We used data from the Medical Birth Registry of Norway, and included all singleton births in gestational weeks 37-42 in Norway, 1999-2019 (n = 1 127 945). We calculated the prevalence of labor induction and outcome measures according to year of birth. We repeated these calculations for each gestational week at birth.

RESULTS

The prevalence of labor induction increased from 9.7% to 25.9%, and the increase was particularly high in gestational week 41. A modest decline in fetal deaths was observed in all gestational weeks, except gestational week 41. The overall decline was from 0.18% in 1999-2004 to 0.13% during 2015-2019. There were no overall changes in other perinatal outcomes. The prevalence of postpartum hemorrhage ≥500 ml increased from 11.4% in 1999 to 30.1% in 2019, and operative deliveries increased slightly. The prevalence of acute cesarean section increased from 6.5% to 9.3%, whereas vacuum and/or forceps assisted deliveries increased from 7.8% to 10.4%.

CONCLUSIONS

A high increase in labor inductions was accompanied by a modest decline in fetal deaths, but no decline in other adverse perinatal outcomes. In settings where the prevalence of adverse perinatal outcomes is low, the beneficial effect of increased use of labor induction may not outweigh the side effects or the costs.

Neurodevelopmental outcomes of preterm infants after randomisation to initial resuscitation with lower (FiO2 <0.3) or higher (FiO2 >0.6) initial oxygen levels. An individual patient meta-analysis

OBJECTIVE

To determine the effects of lower (≤0.3) versus higher (≥0.6) initial fractional inspired oxygen (FiO₂) for resuscitation on death and/or neurodevelopmental impairment (NDI) in infants <32 weeks' gestation.

DESIGN

Meta-analysis of individual patient data from three randomised controlled trials.

SETTING

Neonatal intensive care units.

PATIENTS

543 children <32 weeks' gestation.

INTERVENTION

Randomisation at birth to resuscitation with lower (≤0.3) or higher (≥0.6) initial FiO₂.

OUTCOME MEASURES

Primary: death and/or NDI at 2 years of age.Secondary: post-hoc non-randomised observational analysis of death/NDI according to 5-minute oxygen saturation (SpO₂) below or at/above 80%.

RESULTS

By 2 years of age, 46 of 543 (10%) children had died. Of the 497 survivors, 84 (17%) were lost to follow-up. Bayley Scale of Infant Development (third edition) assessments were conducted on 377 children. Initial FiO₂ was not associated with difference in death and/or disability (difference (95% CI) -0.2%, -7% to 7%, p=0.96) or with cognitive scores <85 (2%, -5% to 9%, p=0.5). Five-minute SpO₂ >80% was associated with decreased disability/death (14%, 7% to 21%) and cognitive scores >85 (10%, 3% to 18%, p=0.01). Multinomial regression analysis noted decreased death with 5-minute SpO₂ ≥80% (odds (95% CI) 09.62, 0.98 to 0.96) and gestation (0.52, 0.41 to 0.65), relative to children without death or NDI.

CONCLUSION

Initial FiO₂ was not associated with difference in risk of disability/death at 2 years in infants <32 weeks' gestation but CIs were wide. Substantial benefit or harm cannot be excluded. Larger randomised studies accounting for patient differences, for example, gestation and gender are urgently needed.

Newborns at risk of Covid-19 - lessons from the last year

After more than 1 year of the SARS-CoV-2 pandemic, a great deal of knowledge on how this virus affects pregnant women, the fetus and the newborn has accumulated. The gap between different guidelines how to handle newborn infants during this pandemic has been minimized, and the American Academy of Pediatrics (AAP)'s recommendations are now more in accordance with those of the World Health Organization (WHO). In this article we summarize present knowledge regarding transmission from mother to the fetus/newborn. Although both vertical and horizontal transmission are rare, SARS-CoV-2 positivity is associated with an increased risk of premature delivery and higher neonatal mortality and morbidity. Mode of delivery and cord clamping routines should not be affected by the mother's SARS-CoV-2 status. Skin to skin contact, rooming in and breastfeeding are recommended with necessary hygiene precautions. Antibodies of infected or vaccinated women seem to cross both the placenta and into breast milk and likely provide protection for the newborn.

Oxygen saturation (SpO2) targeting for newborn infants at delivery: Are we reaching for an impossible unknown?

For more than 200 years, pure oxygen was given ad libitum to newborn infants requiring resuscitation. Due to oxidative stress and injury concerns, a paradigm shift towards using "less" oxygen, including air (21% oxygen) instead of pure (100%) oxygen, occurred about twenty years ago. A decade later, clinicians were advised to adjust fractional inspired oxygen (FiO₂) to target oxygen saturations (SpO₂) that were derived from spontaneously breathing, healthy, mature infants. Whether these recommendations are achievable, beneficial, harmful or redundant is uncertain. The underlying pathology leading to resuscitation varies between infants and may considerably alter an infant's response to supplemental oxygen. In this review, we summarize available evidence for the use of SpO₂ monitoring at delivery for newborn infants, elucidate existing knowledge and service gaps, and suggest future research recommendations that will lead to the safest clinical strategies for this standard and important practice.

Oxygen in the First Minutes of Life in Very Preterm Infants

Even a few minutes of exposure to oxygen in the delivery room in very preterm and immature infants may have detrimental effects. The initial oxygenation in the delivery room should therefore be optimized, but knowledge gaps, including initial fraction of oxygen (FiO2) and how FiO2 should be changed to reach an optimal oxygen saturation measured by pulse oximetry (SpO2) target within the first 5-10 min of life, remain. In order to answer this question, we therefore reviewed relevant literature. For newly born infants with gestational age (GA) <32 weeks in need of positive pressure ventilation (PPV) immediately after birth, we identified 2 fundamental issues: (1) the optimal initial FiO2 and (2) the target SpO2 within the first 5-10 min of life. For newly born infants between 29 and 31 weeks of GA, an initial FiO2 of 0.3 hit the target defined by the International Liaison Committee on Resuscitation (ILCOR) best. Newborn infants with GA <29 weeks in need of PPV and supplementary oxygen, we suggest starting with FiO2 0.3 and adjusting the FiO2 to reach SpO2 of 80% within 5 min of life for best outcomes. Prolonged bradycardia (heart rate <100 bpm for >2 min) is associated with increased risk of adverse outcomes, including death. The combination of strict control of development of SpO2 in the first 10 min of life and a heart rate >100 bpm represents the best tool today to achieve the most optimal outcome in the delivery room of very preterm and immature newborn infants.

Transcriptome analysis reveals dysregulation of genes involved in oxidative phosphorylation in a murine model of retinopathy of prematurity

BACKGROUND

Retinal gene expression pattern is severely altered after exposition to hyperoxia in mice with oxygen-induced retinopathy (OIR), a common model of retinopathy of prematurity. Gene ontology and signaling pathway analyses may add new insights into a better understanding of the pathogenesis of this disease.

METHODS

Seven-day-old C57BL/6J mice (n = 60) were exposed to 75% oxygen for 5 days and then recovered in room air. The controls (n = 60) were kept in the normoxic conditions. Retinas were harvested immediately following hyperoxia, during the phase of maximal neovascularization, and at the time of neovascularization regression. The retinal RNA samples were evaluated for gene expression using mouse gene expression microarrays. DAVID annotation tools were used for gene ontology and pathway analyses.

RESULTS

The most significantly enriched signaling pathways during the neovascularization phase of OIR were: focal adhesion; ECM-receptor interaction; PI3K-Akt; oxidative phosphorylation; and Alzheimer's, Parkinson's and Huntington's disease signaling pathways. Genes involved in apoptosis, cell proliferation, cell differentiation, and immune responses were associated with neovascularization regression.

CONCLUSIONS

Performed analyses revealed the possible involvement of various signaling pathways in OIR pathomechanism, mostly specific to the OIR phase. Dysregulation of genes involved in oxidative phosphorylation may have an impact on neovascularization development.

Reduction in Perinatal Mortality after Implementation of HBB Training at a District Hospital in Mali

BACKGROUND

Mali has a high neonatal mortality rate of 38/1000 live births; in addition the fresh stillbirth rate (FSR) is 23/1000 births and of these one-third are caused by intrapartum events.

OBJECTIVES

The aims are to evaluate the effect of helping babies breathe (HBB) on mortality rate at a district hospital in Kati district, Mali.

METHODS

HBB first edition was implemented in April 2016. One year later the birth attendants were trained in HBB second edition and started frequent repetition training. This is a before and after study comparing the perinatal mortality during the period before HBB training with the period after HBB training, the period after HBB first edition and the period after HBB second edition. Perinatal mortality is defined as FSR plus neonatal deaths in the first 24 h of life.

RESULTS

There was a significant reduction in perinatal mortality rate (PMR) between the period before and after HBB training, from 21.7/1000 births to 6.0/1000 live births; RR 0.27, (95% CI 0.19-0.41; p < 0.0001). Very early neonatal mortality rate (24 h) decreased significantly from 6.3/1000 to 0.8/1000 live births; RR 0.12 (95% CI 0.05-0.33; p = 0.0006). FSR decreased from 15.7/1000 to 5.3/1000, RR 0.33 (95% CI 0.22-0.52; p < 0.0001). No further reduction occurred after introducing the HBB second edition.

CONCLUSION

HBB may be effective in a local first-level referral hospital in Mali.