Outcomes of hypoxic-ischemic encephalopathy in neonates treated with hypothermia

Socioemotional and Psychological Outcomes of Hypoxic-Ischemic Encephalopathy: A Systematic Review

BACKGROUND AND OBJECTIVES

Therapeutic hypothermia has reduced the risk of death or major disability following perinatal hypoxic-ischemic encephalopathy (HIE); however, many children who experience perinatal HIE still go on to develop personal and behavioral challenges, which can be difficult for caregivers and a public health burden for society. Our objective with this review is to systematically identify and synthesize studies that evaluate associations between perinatal HIE and socioemotional or psychological outcomes.

METHODS

We screened all search-returned journal articles from Cochrane Library, Embase, Medline, PsycINFO, Scopus, and Web of Science from data inception through February 1, 2023. Keywords related to HIE (eg, neonatal encephalopathy, neonatal brain injury) and outcomes (eg, social*, emotion*, behav* problem, psycholog*, psychiatr*) were searched with a predefined search string. We included all observational human studies reporting socioemotional or psychological sequelae of term HIE. Study data were recorded on standardized sheets, and the Newcastle-Ottawa Scale was adapted to assess study quality.

RESULTS

We included 43 studies documenting 3244 HIE participants and 2132 comparison participants. We found statistically significant associations between HIE and social and emotional, behavioral, and psychological and psychiatric deficits throughout infancy, childhood, and adolescence (19 studies). The authors of the included studies also report nonsignificant findings (11 studies) and outcomes without statistical comparison (25 studies).

CONCLUSIONS

Perinatal HIE may be a risk factor for a range of socioemotional and psychological challenges in the short- and long-term. Routine screening, early intervention, and follow-up support may be particularly beneficial to this population.

Neurological and Visual Outcomes in Infants and Toddlers Following Therapeutic Hypothermia for Neonatal Hypoxic-Ischemic Encephalopathy

BACKGROUND

The majority of studies have investigated neurodevelopmental outcomes, whereas visual impairment is less explored in children with a history of neonatal (hypoxic-ischemic) encephalopathy. Our aim was to perform a detailed neurological and visual assessment and also to investigate the presence of cerebral visual impairment in infants and toddlers with neonatal encephalopathy.

METHODS

Thirty participants with a history of neonatal encephalopathy, who had been hospitalized for therapeutic hypothermia, underwent a detailed neurological examination at age five to 36 months. Age-matched, 30 healthy children were also enrolled as a control group. All children in the study and control groups received neurological and a comprehensive ophthalmologic examination, including visual field and visual acuity. Presence of cerebral visual impairment was also evaluated clinically.

RESULTS

Rates of cerebral palsy, severe motor impairment, cognitive impairment, epilepsy, and cerebral visual impairment were found to be 20%, 10%, 15.3%, 10%, and 20%, respectively. When compared with healthy controls, oculomotor functions, pupillary light response, refractive parameters, anterior/posterior segment examinations, ocular visual impairment rates, and last, visual acuities were found similar. However, we found a statistically significant increase in visual field defects in our study group.

CONCLUSIONS

It could be better to perform a comprehensive ophthalmologic examination including visual field, visual acuity, and oculomotor functions by a pediatric ophthalmologist to accurately diagnose neurovisual deficits in infants following therapeutic hypothermia. Early identification and rehabilitation of the visual deficits might improve the neurodevelopment in these children.

Therapeutic Interventions in Rat Models of Preterm Hypoxic Ischemic Injury: Effects of Hypothermia, Caffeine, and the Influence of Sex

Infants born prematurely have an increased risk of experiencing brain injury, specifically injury caused by Hypoxia Ischemia (HI). There is no approved treatment for preterm infants, in contrast to term infants that experience Hypoxic Ischemic Encephalopathy (HIE) and can be treated with hypothermia. Given this increased risk and lack of approved treatment, it is imperative to explore and model potential treatments in animal models of preterm injury. Hypothermia is one potential treatment, though cooling to current clinical standards has been found to be detrimental for preterm infants. However, mild hypothermia may prove useful. Caffeine is another treatment that is already used in preterm infants to treat apnea of prematurity, and has shown neuroprotective effects. Both of these treatments show sex differences in behavioral outcomes and neuroprotective effects, which are critical to explore when working to translate from animal to human. The effects and research history of hypothermia, caffeine and how sex affects these treatment outcomes will be explored further in this review article.

Apoptosis and necroptosis occur in the different brain regions of hippocampus in a rat model of hypoxia asphyxia

AIM OF THE STUDY

Hypoxic-ischemic encephalopathy (HIE) is a major cause of newborn brain injury. Apoptosis and necroptosis are two forms of cell death which may occur in HIE but reported data are yet limited. This study investigates the expression of receptor interacting protein kinase (RIPK) 1 and 3, and caspase3, the key modulators of necroptosis and apoptosis, respectively, in a model of HIE to determine whether both forms of cell death occur in the corresponding brain regions.

MATERIALS AND METHODS

Postneonatal day 7 Sprague-Dawley rats were subjected to right carotid artery ligation followed by hypoxia or subjected to skin incision under surgical anesthesia without ligation and hypoxia. Neuroglioma (H4) cell was cultured and subjected to 24 h hypoxic insults. Necrostatin-1, a RIPK1 inhibitor, was administered in both in vivo and in vitro settings before insult.

RESULTS

After hypoxic-ischemic insults, both RIPK1 and RIPK3 expression were significantly increased in the region of hippocampal dentate gyrus in the injurious hemisphere. However, cleaved caspase3 was significantly increased in the hippocampal cornu ammonis 1 region in the injurious hemisphere. After hypoxic insults, RIPK1 and RIPK3 expression was also found in H4 cells. In addition, it was identified that the increased RIPK1 and RIPK3 can be inhibited by necrostatin-1 in both in vivo and in vitro.

CONCLUSIONS

These data indicated that apoptosis and necroptosis occur in different brain regions of hippocampus in a model of HIE which may suggest that strategies to prevent each form of neuronal death is valuable to be developed.

Induction of mesenchymal stem cell‑like transformation in rat primary glial cells using hypoxia, mild hypothermia and growth factors

The transformation of rat primary glial cells into mesenchymal stem cells (MSCs) is intriguing as more seed cells can be harvested. The present study aimed to evaluate the effects of growth factors, hypoxia and mild hypothermia on the transformation of primary glial cells into MSCs. Rat primary glial cells were induced to differentiate by treatment with hypoxia, mild hypothermia and basic fibroblast growth factor (bFGF) and epidermal growth factor (EGF). Immunohistochemistry and western blotting were then used to determine the expression levels of glial fibrillary acidic protein (GFAP), nestin, musashi-1, neuron specific enolase (NSE) and neuronal nuclei (NeuN), in each treatment group. bFGF and EGF increased the proportion of CD44⁺ and CD105⁺ cells, while anaerobic mild hypothermia increased the proportion of CD90⁺ cells. The combination of bFGF and EGF, and anaerobic mild hypothermia increased the proportion of CD29⁺ cells and significantly decreased the proportions of GFAP⁺ cells and NSE⁺ cells. Treatment of primary glial cells with bFGF and EGF increased the expression levels of nestin, Musashi-1, NSE and NeuN. Anaerobic mild hypothermia increased the expression levels of Musashi-1 and decreased the expression levels of NSE and NeuN in glial cells. The results of the present study demonstrated that bFGF, EGF and anaerobic mild hypothermia treatments may promote the transformation of glial cells into MSC-like cells, and that the combination of these two treatments may have the optimal effect.

Mining multi-site clinical data to develop machine learning MRI biomarkers: application to neonatal hypoxic ischemic encephalopathy

BACKGROUND

Secondary and retrospective use of hospital-hosted clinical data provides a time- and cost-efficient alternative to prospective clinical trials for biomarker development. This study aims to create a retrospective clinical dataset of Magnetic Resonance Images (MRI) and clinical records of neonatal hypoxic ischemic encephalopathy (HIE), from which clinically-relevant analytic algorithms can be developed for MRI-based HIE lesion detection and outcome prediction.

METHODS

This retrospective study will use clinical registries and big data informatics tools to build a multi-site dataset that contains structural and diffusion MRI, clinical information including hospital course, short-term outcomes (during infancy), and long-term outcomes (~ 2 years of age) for at least 300 patients from multiple hospitals.

DISCUSSION

Within machine learning frameworks, we will test whether the quantified deviation from our recently-developed normative brain atlases can detect abnormal regions and predict outcomes for individual patients as accurately as, or even more accurately, than human experts. Trial Registration Not applicable. This study protocol mines existing clinical data thus does not meet the ICMJE definition of a clinical trial that requires registration.

Targeting Oxygen in Term and Preterm Infants Starting at Birth

Transition into the extrauterine world is characterized by a substantial increase in oxygen availability to tissue. Exact oxygen provision may be needed to avoid negative consequences of hypoxia or hyperoxia. For term and near-term infants, it is recommended to start with air and titrate the oxygen supplement to the saturation nomogram. However, oxygen supplementation in infants less than 32 weeks' gestation is an unsolved conundrum. At present, the inspired fraction of oxygen is set according to gestational age and blended to achieve targeted saturations and heart rates. Studies are still needed to overcome uncertainties about oxygen supplementation during preterm stabilization.

An Inhibitor of the Mitochondrial Permeability Transition Pore Lacks Therapeutic Efficacy Following Neonatal Hypoxia Ischemia in Mice

Neonatal hypoxic ischemic (HI) brain injury causes lifelong neurologic disability. Therapeutic hypothermia (TH) is the only approved therapy that partially mitigates mortality and morbidity. Therapies specifically targeting HI-induced brain cell death are currently lacking. Intracellular calcium dysregulation, oxidative stress, and mitochondrial dysfunction through the formation of the mitochondrial permeability transition pore (mPTP) are drivers of HI cellular injury. GNX-4728, a small molecule direct inhibitor of the mPTP that increases mitochondrial calcium retention capacity, is highly effective in adult neurodegenerative disease models and could have potential as a therapy in neonatal HI. A dose of GNX-4728, equivalent to that used in animal models, 300 mg/kg, IP was highly toxic in p10 mice. We then tested the hypothesis that acute administration of 30 mg/kg, IP of GNX-4728 immediately after HI in a neonatal mouse model would provide neuroprotection. This non-lethal lower dose of GNX-4728 (30 mg/kg, IP) improved the respiratory control ratio of neonatal female HI brain tissue but not in males. Brain injury, assessed histologically with a novel metric approach at 1 and 30 days after HI, was not mitigated by GNX-4728. Our work demonstrates that a small molecule inhibitor of the mPTP has i) an age related toxicity, ii) a sex-related brain mitoprotective profile after HI but iii) this is not sufficient to attenuate forebrain HI neuropathology.

Passive therapeutic hypothermia during ambulance and helicopter secondary neonatal transport in neonates with hypoxic brain injury: a 10-year retrospective survey

BACKGROUND

Therapeutic hypothermia is a method of treatment in newborns with hypoxic ischemic encephalopathy. Hypothermia should be initiated no later than 6 h after birth. The purpose of this study was to evaluate the quality of the passive therapeutic cooling during neonatal transport.

PURPOSE

The study aims to evaluate the efficiency of our transport in maintenance of target body temperature during transport.

METHODS

We conducted a 10-year retrospective study in neonates, transported by helicopter or ambulance, who received therapeutic passive-induced hypothermia during transport to the Department of Pediatric Surgery and Intensive Therapy at the University Medical Centre Ljubljana between September 1, 2006, and December 31, 2016.

RESULTS

Out of 68 transported newborns, 57 met the criteria for therapeutic induced hypothermia. Eight out of 51 (15.7%) were within therapeutic temperature zone before start of transport while 30 out of 57 (52.6%) were within therapeutic temperature zone at the end of transport. There was a negative correlation between the duration of transport and temperature at the admission (ρ = - 0.306; p = 0.026). A positive correlation was found between the body temperature before and at the end of transport (ρ = 0.410; p = 0,003). A positive correlation between axillary and rectal temperature on admission was found (ρ = 0,832; p < 0,0005). The type of transport, meteorological season, or gender differences did not affect any of measured parameters. Newborns who received chest compression had lower temperature.

CONCLUSION

Therapeutic temperature zone during transport was achieved in 52.6% of transported neonates. Axillary temperature positively correlated with rectal temperature on admission.

Anastasis: recovery from the brink of cell death

Anastasis is a natural cell recovery phenomenon that rescues cells from the brink of death. Programmed cell death such as apoptosis has been traditionally assumed to be an intrinsically irreversible cascade that commits cells to a rapid and massive demolition. Interestingly, recent studies have demonstrated recovery of dying cells even at the late stages generally considered immutable. Here, we examine the evidence for anastasis in cultured cells and in animals, review findings illuminating the potential mechanisms of action, discuss the challenges of studying anastasis and explore new strategies to uncover the function and regulation of anastasis, the identification of which has wide-ranging physiological, pathological and therapeutic implications.

Xenon Combined With Hypothermia in Perinatal Hypoxic-Ischemic Encephalopathy: A Noble Gas, a Noble Mission

Perinatal hypoxia-ischemia is a major cause of neonatal morbidity. It generates primary neuronal damage of the neonatal brain and later secondary damage when reperfusion of the ischemic brain tissue causes a surge of oxygen free radicals and inflammation. This post-hypoxic-ischemic brain damage is a leading cause of motor and intellectual disabilities in survivors. Research worldwide has focused on mitigating this injury. Mild or moderate hypothermia is the standard treatment in many centers. However, its benefit is modest and the search for combinatorial effective neuroprotectants continues. This review focuses on xenon as one such agent. The use of mild to moderate hypothermia is reviewed first. Then promising results on the use of xenon to potentiate the effect of hypothermia in in vitro and in vivo animal experiments are discussed. In the first feasibility study on human neonates, researchers found a significant benefit of using 50% xenon for 18 hours in addition to 72 hours of hypothermia. Yet, this additional benefit of xenon was lacking in a larger cohort study, potentially because xenon was used beyond six hours of birth. The future of using xenon is promising, but further clinical studies are awaited to confirm the feasibility of its routine use and its optimal timing, concentration, and duration, for human neonatal hypoxia-ischemia.

A longitudinal 1H-NMR metabolomics analysis of urine from newborns with hypoxic-ischemic encephalopathy undergoing hypothermia therapy. Clinical and medical legal insights

Perinatal asphyxia is an event affecting around four million newborns worldwide. The 0.5 to 2 per 1000 of full term asphyxiated newborns suffer from hypoxic-ischemic encephalopathy (HIE), which is a frequent cause of death or severe disability and, as consequence, the most common birth injury claim for obstetrics, gynaecologists, and paediatricians. Perinatal asphyxia results from a compromised gas exchange that leads to hypoxemia, hypercapnia, and metabolic acidosis. In this work, we applied a metabolomics approach to investigate the metabolic profiles of urine samples collected from full term asphyxiated newborns with HIE undergoing therapeutic hypothermia (TH), with the aim of identifying a pattern of metabolites associated with HIE and to follow their modifications over time. Urine samples were collected from 10 HIE newborns at birth, during hypothermia (48 hours), at the end of the therapeutic treatment (72 hours), at 1 month of life, and compared with a matched control population of 16 healthy full term newborns. The metabolic profiles were investigated by 1H NMR spectroscopy coupled with multivariate statistical methods such as principal component analysis and orthogonal partial least square discriminant analysis. Multivariate analysis indicated significant differences between the urine samples of HIE and healthy newborns at birth. The altered metabolic patterns, mainly originated from the depletion of cellular energy and homeostasis, seem to constitute a characteristic of perinatal asphyxia. The HIE urine metabolome changes over time reflected either the effects of TH and the physiological growth of the newborns. Of interest, the urine metabolic profiles of the HIE non-surviving babies, characterized by the increased excretion of lactate, resulted significantly different from the rest of HIE population.

Uptake of dendrimer-drug by different cell types in the hippocampus after hypoxic-ischemic insult in neonatal mice: Effects of injury, microglial activation and hypothermia

Perinatal hypoxic-ischemic encephalopathy (HIE) can result in neurodevelopmental disability, including cerebral palsy. The only treatment, hypothermia, provides incomplete neuroprotection. Hydroxyl polyamidoamine (PAMAM) dendrimers are being explored for targeted delivery of therapy for HIE. Understanding the biodistribution of dendrimer-conjugated drugs into microglia, neurons and astrocytes after brain injury is essential for optimizing drug delivery. We conjugated N-acetyl-L-cysteine to Cy5-labeled PAMAM dendrimer (Cy5-D-NAC) and used a mouse model of perinatal HIE to study effects of timing of administration, hypothermia, brain injury, and microglial activation on uptake. Dendrimer conjugation delivered therapy most effectively to activated microglia but also targeted some astrocytes and injured neurons. Cy5-D-NAC uptake was correlated with brain injury in all cell types and with activated morphology in microglia. Uptake was not inhibited by hypothermia, except in CD68+ microglia. Thus, dendrimer-conjugated drug delivery can target microglia, astrocytes and neurons and can be used in combination with hypothermia for treatment of HIE.

Early neonatal death: A challenge worldwide

Early neonatal death (ENND), defined as the death of a newborn between zero and seven days after birth, represents 73% of all postnatal deaths worldwide. Despite a 50% reduction in childhood mortality, reduction of ENND has significantly lagged behind other Millennium Developmental Goal achievements and is a growing contributor to overall mortality in children aged <5 years. The etiology of ENND is closely related to the level of a country's industrialization. Hence, prematurity and congenital anomalies are the leading causes in high-income countries. Furthermore, sudden unexpected early neonatal deaths (SUEND) and collapse have only recently been identified as relevant and often preventable causes of death. Concomitantly, perinatal-related events such as asphyxia and infections are extremely relevant in Africa, South East Asia, and Latin America and, together with prematurity, are the principal contributors to ENND. In high-income countries, according to current research evidence, survival may be improved by applying antenatal and perinatal therapies and immediate newborn resuscitation, as well as by centralizing at-risk deliveries to centers with appropriate expertise available around the clock. In addition, resources should be allocated to the close surveillance of newborn infants, especially during the first hours of life. Many of the conditions leading to ENND in low-income countries are preventable with relatively easy and cost-effective interventions such as contraception, vaccination of pregnant women, hygienic delivery at a hospital, training health care workers in resuscitation practices, simplified algorithms that allow for early detection of perinatal infections, and early initiation of breastfeeding and skin-to-skin care. The future is promising. As initiatives undertaken in previous decades have led to substantial reduction in childhood mortality, it is expected that new initiatives targeting the perinatal/neonatal periods are bound to reduce ENND and provide these babies with a better future.

Therapeutic Hypothermia Provides Variable Protection against Behavioral Deficits after Neonatal Hypoxia-Ischemia: A Potential Role for Brain-Derived Neurotrophic Factor

BACKGROUND

Despite treatment with therapeutic hypothermia (TH), infants who survive hypoxic ischemic (HI) encephalopathy (HIE) have persistent neurological abnormalities at school age. Protection by TH against HI brain injury is variable in both humans and animal models. Our current preclinical model of hypoxia-ischemia (HI) and TH displays this variability of outcomes in neuropathological and neuroimaging end points with some sexual dimorphism. The detailed behavioral phenotype of this model is unknown. Whether there is sexual dimorphism in certain behavioral domains is also not known. Brain-derived neurotrophic factor (BDNF) supports neuronal cell survival and repair but may also be a marker of injury. Here, we characterize the behavioral deficits after HI and TH stratified by sex, as well as late changes in BDNF and its correlation with memory impairment.

METHODS

HI was induced in C57BL6 mice on postnatal day 10 (p10) (modified Vannucci model). Mice were randomized to TH (31°C) or normothermia (NT, 36°C) for 4 h after HI. Controls were anesthesia-exposed, age- and sex-matched littermates. Between p16 and p39, growth was followed, and behavioral testing was performed including reflexes (air righting, forelimb grasp and negative geotaxis) and sensorimotor, learning, and memory skills (open field, balance beam, adhesive removal, Y-maze tests, and object location task [OLT]). Correlations between mature BDNF levels in the forebrain and p42 memory outcomes were studied.

RESULTS

Both male and female HI mice had an approximately 8-12% lower growth rate (g/day) than shams (p ≤ 0.01) by p39. TH ameliorated this growth failure in females but not in males. In female mice, HI injury prolonged the time spent at the periphery (open field) at p36 (p = 0.004), regardless of treatment. TH prevented motor impairments in the balance beam and adhesive removal tests in male and female mice, respectively (p ≤ 0.05). Male and female HI mice visited the new arm of the Y-maze 12.5% (p = 0.05) and 10% (p = 0.03) less often than shams, respectively. Male HI mice also had 35% lower exploratory preference score than sham (p ≤ 0.001) in the OLT. TH did not prevent memory impairments found with Y-maze testing or OLT in either sex (p ≤ 0.01) at p26. At p42, BDNF levels in the forebrain ipsilateral to the HI insult were 1.7- to 2-fold higher than BDNF levels in the sham forebrain, and TH did not prevent this increase. Higher BDNF levels in the forebrain ipsilateral to the insult correlated with worse performance in the Y-maze in both sexes and in OLT in male mice (p = 0.01).

CONCLUSIONS

TH provides benefit in specific domains of behavior following neonatal HI. In general, these benefits accrued to both males and females, but not in all areas. In some domains, such as memory, no benefit of TH was found. Late differences in individual BDNF levels may explain some of these findings.

Oxidative Stress in Hypoxic-Ischemic Encephalopathy: Molecular Mechanisms and Therapeutic Strategies

Hypoxic-ischemic encephalopathy (HIE) is one of the leading causes of morbidity and mortality in neonates. Because of high concentrations of sensitive immature cells, metal-catalyzed free radicals, non-saturated fatty acids, and low concentrations of antioxidant enzymes, the brain requires high levels of oxygen supply and is, thus, extremely sensitive to hypoxia. Strong evidence indicates that oxidative stress plays an important role in pathogenesis and progression. Following hypoxia and ischemia, reactive oxygen species (ROS) production rapidly increases and overwhelms antioxidant defenses. A large excess of ROS will directly modify or degenerate cellular macromolecules, such as membranes, proteins, lipids, and DNA, and lead to a cascading inflammatory response, and protease secretion. These derivatives are involved in a complex interplay of multiple pathways (e.g., inflammation, apoptosis, autophagy, and necrosis) which finally lead to brain injury. In this review, we highlight the molecular mechanism for oxidative stress in HIE, summarize current research on therapeutic strategies utilized in combating oxidative stress, and try to explore novel potential clinical approaches.

The Role of the Neurointensive Care Nursery for Neonatal Encephalopathy

Neonatal encephalopathy due to intrapartum events is estimated at 1 to 2 per 1000 live births in high-income countries. Outcomes have improved over the past decade due to implementation of therapeutic hypothermia, the only clinically available neuroprotective strategy for hypoxic-ischemic encephalopathy. Neonatal encephalopathy is the most common condition treated within a neonatal neurocritical care unit. Neonates with encephalopathy benefit from a neurocritical care approach due to prevention of secondary brain injury through attention to basic physiology, earlier recognition and treatment of neurologic complications, consistent management using guidelines and protocols, and use of optimized teams at dedicated referral centers.

A new approach to define acute kidney injury in term newborns with hypoxic ischemic encephalopathy

BACKGROUND

Current definitions of acute kidney injury (AKI) are not sufficiently sensitive to identify all newborns with AKI during the first week of life.

METHODS

To determine whether the rate of decline of serum creatinine (SCr) during the first week of life can be used to identify newborns with AKI, we reviewed the medical records of 106 term neonates at risk of AKI who were treated with hypothermia for hypoxic ischemic encephalopathy (HIE).

RESULTS

Of the newborns enrolled in the study, 69 % showed a normal rate of decline of SCr to ≥50 % and/or reached SCr levels of ≤0.6 mg/dl before the 7th day of life, and therefore had an excellent clinical outcome (control group). Thirteen newborns with HIE (12 %) developed AKI according to an established neonatal definition (AKI-KIDGO group), and an additional 20 newborns (19 %) showed a rate of decline of SCr of <33, <40, and <46 % from birth to days 3, 5, or 7 of life, respectively (delayed rise in estimated SCr clearance group). Compared to the control group, newborns in the other two groups required more days of mechanical ventilation and vasopressor drugs and had higher gentamicin levels, more fluid overload, lower urinary epidermal growth factor levels, and a prolonged length of stay.

CONCLUSIONS

The rate of decline of SCr provides a sensitive approach to identify term newborns with AKI during the first week of life.

Neonatal encephalopathy in New Zealand: Demographics and clinical outcome

AIM

To establish the incidence of moderate to severe neonatal encephalopathy (NE) in term infants from New Zealand and to document demographic characteristics and neonatal outcomes.

METHODS

Cases were reported monthly via the New Zealand Paediatric Surveillance Unit (NZPSU). Data were collected from paediatricians for neonatal items and lead maternity carers for pregnancy and birth details. Term neonatal deaths in the Perinatal and Maternal Mortality Review Committee dataset that were because of hypoxia and/or neonatal deaths from hypoxic ischaemic encephalopathy were added to the cases identified via the NZPSU, if they had not previously been ascertained.

RESULTS

For the period January 2010 to December 2012, there were 227 cases, equivalent to a rate of 1.30/1000 term births (95% CI 1.14-1.48). Rates of NE were high in babies of Pacific and Indian mothers but only reached statistical significance for the comparison between Pacific and NZ European. There was also a significant increase in NE rates with increasing deprivation. Resuscitation at birth was initiated for 209 (92.1%) infants with NE. Mechanical ventilation was required, following neonatal unit admission, in 171 (75.3%) infants. Anticonvulsants were used in 157 (69.2%) infants with phenobarbitone (65.6%), phenytoin (14.5%) and benzodiazapines (21.1%), the most common. Cooling was induced in 168 infants (74%) with 145 (86.3%) reported as commenced within a 6-h window.

CONCLUSIONS

The rate of NE in New Zealand is consistent with reported international rates. Establishing antecedent factors for NE is an important part of improving care, which may inform strategic efforts to decrease rates of NE.

Localized intestinal perforations as a potential complication of brain hypothermic therapy for perinatal asphyxia

Brain hypothermic therapy (BHT) is becoming a frequently used standard of care for perinatal asphyxia. Although cardiovascular side effects, coagulation disorders, renal impairment, electrolyte abnormalities, impaired liver function, opportunistic infections, and skin lesions are well-known adverse effects of BHT in newborns, little information is available on the clinical features of intestinal perforation-related BHT. We herein report a case of therapeutic brain cooling for perinatal asphyxia complicated by localized intestinal perforation. In practice, the neonatologist should be aware that intestinal perforation in an infant with perinatal asphyxia is possible, particularly following BHT.

Neuroprotective Strategies after Neonatal Hypoxic Ischemic Encephalopathy

Neonatal hypoxic ischemic encephalopathy (HIE) is a devastating disease that primarily causes neuronal and white matter injury and is among the leading cause of death among infants. Currently there are no well-established treatments; thus, it is important to understand the pathophysiology of the disease and elucidate complications that are creating a gap between basic science and clinical translation. In the development of neuroprotective strategies and translation of experimental results in HIE, there are many limitations and challenges to master based on an appropriate study design, drug delivery properties, dosage, and use in neonates. We will identify understudied targets after HIE, as well as neuroprotective molecules that bring hope to future treatments such as melatonin, topiramate, xenon, interferon-beta, stem cell transplantation. This review will also discuss some of the most recent trials being conducted in the clinical setting and evaluate what directions are needed in the future.

Early Anatomical Injury Patterns Predict Epilepsy in Head Cooled Neonates With Hypoxic-Ischemic Encephalopathy

BACKGROUND

Our aim was to determine whether early anatomical injury patterns on magnetic resonance imaging-correlate with the development of postneonatal epilepsy in infants treated with selective head cooling for hypoxic-ischemic encephalopathy.

METHODS

We retrospectively analyzed infants ≥35 weeks' gestation born between 2008 and 2013 and followed for at least one year at Northwestern University. All had brain magnetic resonance imaging scans at days 4-5 and electroencephalographs during rewarming and at 3 to 6 months of age.

RESULTS

Outcome was favorable for our cohort of 73 individuals with a mean follow-up of 41 (±7) months. The majority (66%) survived with no seizure recurrence, whereas 13 (18%) developed postneonatal epilepsy, including eight who had infantile spasms. Twelve infants (16%) died. The most common magnetic resonance imaging pattern was diffuse brain injury involving both cortical and subcortical gray matter (26/73, 35%), followed by cortical and subcortical white matter injury (18/73, 25%) and normal magnetic resonance imaging (16/73, 22%). In 13 infants (18%), the brainstem was involved in addition to cortical and subcortical gray matter; nine died and all four surviving infants developed infantile spasms. All 18 infants with cortical and subcortical white matter injury survived and none developed postneonatal epilepsy. The risk of postneonatal epilepsy was associated with injury involving subcortical regions (basal ganglia, thalamus ± brainstem) (12/39 versus 1/34, P < 0.003).

CONCLUSIONS

Brainstem injury was highly predictive of infantile spasms, whereas cortical injury alone predicted low risk for short-term postneonatal epilepsy. Location of anatomical injury on magnetic resonance imaging can be an early predictive factor for development of infantile spasms and inform prognostic decisions in newborns treated with selective head cooling for hypoxic-ischemic encephalopathy.

Hypoxia-ischemia and therapeutic hypothermia in the neonatal mouse brain--a longitudinal study

Therapeutic hypothermia is standard of care for infants with hypoxic ischemic encephalopathy. Murine models of hypoxic-ischemic injury exist; however, a well-established mouse model of therapeutic hypothermia following hypoxic-ischemic injury is lacking. The goal of this study was to develop a full-term-equivalent murine model of therapeutic hypothermia after hypoxia-ischemia and examine magnetic resonance imaging, behavior, and histology in a region and sex specific manner. Hypoxic-ischemic injury was induced at postnatal day 10 in C57BL6 mice using a modified Vannucci model. Mice were randomized to control, hypothermia (31˚C for 4h), or normothermia (36˚C) following hypoxic-ischemic injury and stratified by sex. T2-weighted magnetic resonance imaging was obtained at postnatal day 18 and 30 and regional and total cerebral and cerebellar volumes measured. Behavioral assessments were performed on postnatal day 14, 21, and 28. On postnatal day 18, normothermic mice had smaller cerebral volumes (p < 0.001 vs. controls and p = 0.009 vs. hypothermia), while at postnatal day 30 both injured groups had smaller volumes than controls. When stratified by sex, only normothermia treated male mice had smaller cerebral volumes (p = 0.001 vs. control; p = 0.008 vs. hypothermia) at postnatal day 18, which persisted at postnatal day 30 (p = 0.001 vs. control). Female mice had similar cerebral volumes between groups at both day 18 and 30. Cerebellar volumes of hypothermia treated male mice differed from control at day 18, but not at 30. Four hours of therapeutic hypothermia in this murine hypoxic-ischemic injury model provides sustained neuroprotection in the cerebrum of male mice. Due to variable degree of injury in female mice, response to therapeutic hypothermia is difficult to discern. Deficits in female behavior tests are not fully explained by imaging measures and likely represent injury not detectable by volume measurements alone.

Perinatal outcomes following an earlier post-term labour induction policy: a historical cohort study

OBJECTIVE

To assess the changes in perinatal outcomes in children born from 37 weeks of gestation after implementation of a more proactive labour induction practice from 2009.

DESIGN

Register-based cohort study.

SETTING

Denmark, 2000-12.

POPULATION

Newborns from 37 weeks of gestation.

METHODS

Perinatal outcomes were estimated using a logistic regression analysis with adjustment for gestational age, maternal age, parity, plurality, smoking and body mass index.

MAIN OUTCOME MEASURES

Perinatal outcomes.

RESULTS

A total of 770 926 infants were included. Labour induction from 37 weeks increased from 9.7% in 2000-02 to 22.5% in 2011-12. From 2003-05 to 2011-12, the risk of umbilical cord pH < 7.0 decreased by 23%; odds ratio (OR) 0.77 (95% confidence interval 0.67-0.89), and the adjusted OR of Apgar score < 7 at 5 minutes was unchanged. The risk of admission to neonatal intensive care units increased by 56%; OR 1.56 (1.47-1.66), whereas the risk of neonatal deaths decreased by 44%; OR 0.56 (0.45-0.70). The risk of cerebral palsy was from 2000-02 to 2009-10 reduced by 26%; OR 0.74 (0.60-0.90). The proportion of infants born with fetal weight ≥ 4500 g decreased by one-third; OR 0.68 (0.65-0.71). However, the risk of shoulder dystocia increased by 32%; OR 1.32 (1.21-1.44), whereas the risk of peripheral nerve injuries was reduced by 43%; OR 0.57 (0.45-0.73).

CONCLUSION

The results suggest an overall improvement in perinatal outcomes as a result of a more proactive post-term labour induction practice.