The impact of neonatal intensive care practices on the developing brain

An embodied approach to fetal and newborn perceptual and sensorimotor development

The embodied approach argues that interaction with the environment plays a crucial role in brain development and that the presence of sensory effects generated by movements is fundamental. The movement of the fetus is initially random. Then, the repeated execution of the movement creates a link between it and its sensory effects, allowing the selection of movements that produce expected sensations. During fetal life, the brain develops from a transitory fetal circuit to the permanent cortical circuit, which completes development after birth. Accordingly, this process must concern the interaction of the fetus with the intrauterine environment and of the newborn with the new aerial environment, which provides a new sensory stimulation, light. The goal of the present review is to provide suggestions for neuroscientific research capable of shedding light on brain development process by describing from a functional point of view the relationship between the motor and sensory abilities of fetuses and newborns and the increasing complexity of their interaction with objects in the womb and outside of it.

Relationship between Maternal Vitamin D Levels and Adverse Outcomes

Vitamin D (VD), a fat-soluble vitamin, has a variety of functions that are important for growth and development, including regulation of cell differentiation and apoptosis, immune system development, and brain development. As such, VD status during pregnancy is critical for maternal health, fetal skeletal growth, and optimal pregnancy outcomes. Studies have confirmed that adverse pregnancy outcomes, such as preeclampsia, low birth weight, neonatal hypocalcemia, poor postnatal growth, skeletal fragility, and increased incidence of autoimmune diseases, can be associated with low VD levels during pregnancy and infancy. Thus, there is growing interest in the role of VD during pregnancy. This review summarizes the potential adverse health outcomes of maternal VD status during pregnancy for both mother and offspring (gestational diabetes mellitus, hypertensive gestational hypertension, intrauterine growth restriction, miscarriage, stillbirth, and preterm birth) and discusses the underlying mechanisms (regulation of cytokine pathways, immune system processing, internal secretion, placental function, etc.) of VD in regulating each of the outcomes. This review aims to provide a basis for public health intervention strategies to reduce the incidence of adverse pregnancies.

Sensory-based interventions in the NICU: systematic review of effects on preterm brain development

BACKGROUND

Infants born preterm are known to be at risk for abnormal brain development and adverse neurobehavioral outcomes. To improve early neurodevelopment, several non-pharmacological interventions have been developed and implemented in the neonatal intensive care unit (NICU). Sensory-based interventions seem to improve short-term neurodevelopmental outcomes in the inherently stressful NICU environment. However, how this type of intervention affects brain development in the preterm population remains unclear.

METHODS

A systematic review of the literature was conducted for published studies in the past 20 years reporting the effects of early, non-pharmacological, sensory-based interventions on the neonatal brain after preterm birth.

RESULTS

Twelve randomized controlled trials (RCT) reporting short-term effects of auditory, tactile, and multisensory interventions were included after the screening of 1202 articles. Large heterogeneity was identified among studies in relation to both types of intervention and outcomes. Three areas of focus for sensory interventions were identified: auditory-based, tactile-based, and multisensory interventions.

CONCLUSIONS

Diversity in interventions and outcome measures challenges the possibility to perform an integrative synthesis of results and to translate these for evidence-based clinical practice. This review identifies gaps in the literature and methodological challenges for the implementation of RCTs of sensory interventions in the NICU.

IMPACT

This paper represents the first systematic review to investigate the effect of non-pharmacological, sensory-based interventions in the NICU on neonatal brain development. Although reviewed RCTs present evidence on the impact of such interventions on the neonatal brain following preterm birth, it is not yet possible to formulate clear guidelines for clinical practice. This review integrates existing literature on the effect of sensory-based interventions on the brain after preterm birth and identifies methodological challenges for the conduction of high-quality RCTs.

Serial Thyroid Function Test in Very Low Birth Weight Neonates

Thyroid dysfunction is more common in preterm and low birth weight infants, and may be missed if thyroid function test (TFT) is not repeated. Thus, we attempted to study the pattern of thyroid function among very low birth weight (VLBW) infants with birth weight less than 1,500 g by serial TFTs. Serum free thyroxine (FT4) and thyrotropin (thyroid-stimulating hormone [TSH]) levels of VLBW infants were tested on fifth to seventh days of life and repeated after 4 weeks of age. Based on serial FT4 and TSH results, abnormal TFT was classified into four groups—transient hypothyroxinemia of prematurity (THOP), transient hyperthyrotropinemia (THT), delayed TSH rise, and overt congenital hypothyroidism (CH). Stata 15.1 (Stata Corp, Texas, United States) was used for analysis. Ninety-six VLBW infants were enrolled with mean gestational age of 30.5 ± 2.7 weeks and median (interquartile range) birth weight of 1,200 (317) g. Out of 96 cases, 30 (31.2%) infants had abnormal TFT. Ten (10.4%) infants had THOP, 7 (7.3%) infants had THT, 11 (11.5%) infants had delayed TSH rise, and 2 (2.1%) infants had overt CH. There were no significant differences in demographic profile and clinical characteristics between neonates with normal and abnormal TFTs. Five infants required levothyroxine supplementation (two infants with overt CH and three infants with delayed TSH rise). VLBW neonates have higher incidence of CH and delayed rise of TSH in this study. In resource-limited settings, repeating TFTs at least once after 4 weeks of age may be suggested to identify delayed rise of TSH which may need intervention.

Probabilistic graphical model identifies clusters of EEG patterns in recordings from neonates

OBJECTIVES

In this paper we introduce a novel method for the evaluation of neonatal brain function via multivariate EEG (electroencephalography) signal processing and embedding into a probabilistic graph, the so called Chow-Liu tree.

METHODS

Using 28 EEG recordings of preterm and term neonate infants the complex features of the EEG signals were constructed in the form of a Chow-Liu tree. The trees were embedded into a 3 dimensional Euclidean space. Clustering of specific EEG patterns was done by complete linkage algorithm.

RESULTS

Our analytic tool was able to build clusters of patients with pathological EEG findings. In particular, we were able to make a visual proof on a 3d multidimensional scaling coordinate system with a good performance. The distances (graph edit distance) between Chow-Liu trees of different infants were proportional to the clinical findings of corresponding infants.

CONCLUSION

Our method may provide a basis for the future development of a diagnostic/prognostic non-invasive brain monitoring tool which will be able to differentiate between a variety of complex clinical findings.

SIGNIFICANCE

This model addresses relevant issues in neonatology and neuropediatrics in terms of identification of possible clinical factors which interfere with normal brain development and will allow fast unbiased recognition of infants with specific pathological EEG findings.

Neuroprotection of the preterm brain

Despite notable advances in the care and survival of preterm infants, a significant proportion of preterm neonates will have life-long cognitive, behavioral, and motor deficits, and robustly effective neuroprotective strategies are still missing. These therapies must target the pathophysiologic mechanisms observed in contemporaneous infants and rely on modern epidemiology, imaging, and experimental models and assessment techniques. Two drugs, magnesium sulfate and caffeine, are already in use in several units, and although their targets are apnea of prematurity and myometrial contractility (respectively), they do offer improved odds of positive outcomes. Nevertheless, these drugs have limited efficacy, and NICU-to-NICU administration varies greatly. As such, there is an obvious need for additional specific neurotherapeutic strategies to further enhance the outcome of this very fragile population of neonates. The chapter reviews these issues, highlights bottlenecks that need to be solved for meaningful progress in the field, and proposes future innovative avenues for intervention, including delayed interventions.

Preventing childhood and lifelong disability: Maternal dietary supplementation for perinatal brain injury

The majority of brain injuries that lead to cerebral palsy, developmental disability, and mental health disorders have their onset in utero. These lifelong conditions come with great economic and emotional burden as they impact function in nearly all domains of affected individuals' lives. Unfortunately, current therapeutic options are limited. There remains a focus on rescue, rehabilitation, and regeneration after the injury has occurred, rather than aiming to prevent the initial injury. Prevention would imply treating the mother during pregnancy to alter the fetal environment and in turn, treat the fetus. Fear of harming the developing fetus remains as a result of errors of the past such as the release of thalidomide. In this review, we outline evidence from animal studies and clinical trials that have explored maternal dietary supplementation with natural health products (including nutraceuticals and functional foods) for perinatal brain injury prevention. Namely, we discuss magnesium sulphate, creatine, choline, melatonin, resveratrol and broccoli sprouts/sulforaphane. Although clinical trials have only been completed in this realm for magnesium sulphate, results in animal models have been promising, suggesting that this is a productive avenue for further research. Natural health products may provide safe, effective, affordable, and easily accessible prevention of fetal brain injury and resulting lifelong disabilities.

Timing for the Introduction of Cycled Light for Extremely Preterm Infants: A Randomized Controlled Trial

Day-night cycled light improves health outcomes in preterm infants, yet the best time to institute cycled light is unclear. The hypothesis of this study was that extremely preterm infants receiving early cycled light would have better health and developmental outcomes than infants receiving late cycled light. Infants born at ≤28 weeks gestation were randomly assigned to early cycled light (ECL) starting at 28 weeks postmenstrual age [PMA] or late cycled light (LCL), starting at 36 weeks PMA. Daylight was 200-600 lux and night was 5-30 lux. Primary outcomes were weight over time and length of hospitalization. Secondary outcomes were hospital costs, sleep development, and neurodevelopment at 9, 18, and 24 months corrected age. Of 121 infants randomized, 118 were included in analysis. Weight gain in the two groups did not differ significantly but increased across time in both groups. In PMA weeks 36-44, the mean weight gain was 193.8 grams in the ECL group compared to 176.3 grams in the LCL group. Effect sizes for weight were Cohen d = 0.26 and 0.36 for 36 and 44 weeks PMA. Infants in the ECL group went home an average of 5.5 days earlier than the LCL group, but this difference was not statistically significant. There were no group differences on neurodevelopmental outcomes. Although statistically non-significant, clinically important differences of improved weight gain and decreased hospital stay were observed with ECL. The small observed effect sizes on weight during hospitalization should be considered in future cycled light research with extremely preterm infants. © 2017 Wiley Periodicals, Inc.

Human amnion epithelial cells rescue cell death via immunomodulation of microglia in a mouse model of perinatal brain injury

BACKGROUND

Human amnion epithelial cells (hAECs) are clonogenic and have been proposed to reduce inflammatory-induced tissue injury. Perturbation of the immune response is implicated in the pathogenesis of perinatal brain injury; modulating this response could thus be a novel therapy for treating or preventing such injury. The immunomodulatory properties of hAECs have been shown in other animal models, but a detailed investigation of the effects on brain immune cells following injury has not been undertaken. Here, we investigate the effects of hAECs on microglia, the first immune responders to injury within the brain.

METHODS

We generated a mouse model combining neonatal inflammation and perinatal hyperoxia, both of which are risk factors associated with perinatal brain injury. On embryonic day 16 we administered lipopolysaccharide (LPS), or saline (control), intra-amniotically to C57Bl/6 J mouse pups. On postnatal day (P)0, LPS pups were placed in hyperoxia (65% oxygen) and control pups in normoxia for 14 days. Pups were given either hAECs or saline intravenously on P4.

RESULTS

At P14, relative to controls, LPS and hyperoxia pups had reduced body weight, increased density of apoptotic cells (TUNEL) in the cortex, striatum and white matter, astrocytes (GFAP) in the white matter and activated microglia (CD68) in the cortex and striatum, but no change in total microglia density (Iba1). hAEC administration rescued the decreased body weight and reduced apoptosis and astrocyte areal coverage in the white matter, but increased the density of total and activated microglia. We then stimulated primary microglia (CD45lowCD11b+) with LPS for 24 h, followed by co-culture with hAEC conditioned medium for 48 h. hAEC conditioned medium increased microglial phagocytic activity, decreased microglia apoptosis and decreased M1 activation markers (CD86). Stimulating hAECs for 24 h with LPS did not alter release of cytokines known to modulate microglia activity.

CONCLUSIONS

These data demonstrate that hAECs can directly immunomodulate brain microglia, probably via release of trophic factors. This observation offers promise that hAECs may afford therapeutic utility in the management of perinatal brain injury.

The Correlation Between Serum Vitamin D Deficiency and Preterm Birth

BACKGROUND Preterm birth is an important cause of death and developmental disorder in neonates. Vitamin D deficiency has been shown to regulate body inflammatory factor levels that stimulate elevation of uterine contraction hormones, such as prostaglandin, thus causing preterm birth. However, current observations regarding the relationship between vitamin D and preterm birth are inconsistent. We performed a nested case-control study to investigate the effect of vitamin D on preterm birth. MATERIAL AND METHODS A prospective cohort study included 200 cases of pregnant women in our hospital from May 2013 to May 2015. Blood samples were collected from early, middle, and late stages of pregnancy. Forty-six patients with preterm delivery were compared with age-matched full-term delivery cases (N=92). High performance liquid chromatography-mass spectrometry (HPLC-MS) was used to detect serum levels of 25(OH)D, 25(OH)D2, and 25(OH)D3. Logistic regression was performed to analyze the correlation between 25(OH)D and risk of preterm birth. RESULTS No significant difference in age, smoking/drinking, education level, BMI and vitamin D levels was found between the preterm birth group and full-term delivery group. No significant difference was found for vitamin D levels across different stages of pregnancy; no difference in concentration of 25(OH)D related to preterm birth risk was found. After adjusting for potentially confounding factors, serum vitamin D level did not increase the risk of preterm birth. CONCLUSIONS This study did not found evidence of an increase in preterm birth risk related to vitamin D level during pregnancy.

The onset of visual experience gates auditory cortex critical periods

Sensory systems influence one another during development and deprivation can lead to cross-modal plasticity. As auditory function begins before vision, we investigate the effect of manipulating visual experience during auditory cortex critical periods (CPs) by assessing the influence of early, normal and delayed eyelid opening on hearing loss-induced changes to membrane and inhibitory synaptic properties. Early eyelid opening closes the auditory cortex CPs precociously and dark rearing prevents this effect. In contrast, delayed eyelid opening extends the auditory cortex CPs by several additional days. The CP for recovery from hearing loss is also closed prematurely by early eyelid opening and extended by delayed eyelid opening. Furthermore, when coupled with transient hearing loss that animals normally fully recover from, very early visual experience leads to inhibitory deficits that persist into adulthood. Finally, we demonstrate a functional projection from the visual to auditory cortex that could mediate these effects.

Visual and auditory systems influence each other during development. Here, the authors show that the onset of eyelid opening regulates critical points during which the auditory cortex is sensitive to hearing loss or the restoration of hearing

Clinical trials of medicines in neonates: the influence of ethical and practical issues on design and conduct

In the past, there has been a perception that ethical and practical problems limit the opportunities for research in neonates. This perception is no longer appropriate. It is now clear that research about the medicines used in neonates is an ethical requirement. It is possible to conduct high quality research in neonates if the research team adapt to the characteristics of this population. Good practice involves respecting the specific needs of newborn babies and their families by adopting relevant approaches to study design, recruitment, pharmacokinetic studies and safety assessment. Neonatal units have a unique culture that requires careful development in a research setting. Clinical investigators need to recognize the clinical and ethical imperative to conduct rigorous research. Industry needs to engage with neonatal networks early in the process of drug development, preferably before contacting regulatory agencies. Follow-up over 3-5 years is essential for the evaluation of medicines in neonates and explicit funding for this is required for the assessment of the benefit and risk of treatments given to sick newborn babies. The views of parents must be central to the development of studies and the research agenda. Ethical and practical problems are no longer barriers to research in neonates. The current challenges are to disseminate good practice and maximize capacity in order to meet the need for research among newborn babies.

Investigating the use of support vector machine classification on structural brain images of preterm-born teenagers as a biological marker

Preterm birth has been shown to induce an altered developmental trajectory of brain structure and function. With the aid support vector machine (SVM) classification methods we aimed to investigate whether MRI data, collected in adolescence, could be used to predict whether an individual had been born preterm or at term. To this end we collected T1-weighted anatomical MRI data from 143 individuals (69 controls, mean age 14.6y). The inclusion criteria for those born preterm were birth weight ≤ 1500g and gestational age < 37w. A linear SVM was trained on the grey matter segment of MR images in two different ways. First, all the individuals were used for training and classification was performed by the leave-one-out method, yielding 93% correct classification (sensitivity = 0.905, specificity = 0.942). Separately, a random half of the available data were used for training twice and each time the other, unseen, half of the data was classified, resulting 86% and 91% accurate classifications. Both gestational age (R = -0.24, p<0.04) and birth weight (R = -0.51, p < 0.001) correlated with the distance to decision boundary within the group of individuals born preterm. Statistically significant correlations were also found between IQ (R = -0.30, p < 0.001) and the distance to decision boundary. Those born small for gestational age did not form a separate subgroup in these analyses. The high rate of correct classification by the SVM motivates further investigation. The long-term goal is to automatically and non-invasively predict the outcome of preterm-born individuals on an individual basis using as early a scan as possible.

Establishing a hypothermia service for infants with suspected hypoxic-ischemic encephalopathy

The translation of new treatments based upon established evidence into clinical practice is often difficult. The establishment of a therapeutic hypothermia (TH) service and a related cooling register would provide the opportunity to examine how a new therapy becomes implemented in a country or region. The objectives of a TH program should be: to provide guidance to clinicians who are considering the introduction of this new therapy; to ensure standardized clinical practices; to audit the implementation and conduct of TH; to provide surveillance for cooling-related adverse effects; and to evaluate the subsequent neurodevelopmental outcome. Prior to the use of TH, the most important practices to prioritize during its implementation should be identified and include the following: ensure timely identification of infants with neonatal encephalopathy; develop a coordinated system with the local or regional referral cooling center; develop a transport team capable of performing cooling during transport; ensure that each participating unit has access to a national encephalopathy register, and have developmental follow-up arrangements in place that are appropriate and uniform for the region/country.

Drug effects on endogenous brain activity in preterm babies

BACKGROUND

Animal experiments have suggested that the quality of the early intermittent brain activity is important for shaping neuronal connectivity during developmental phase that corresponds to early prematurity. This is a pilot study aiming to assess whether spontaneous activity transients (SAT) in the early preterm babies are affected by drugs that are routinely used in neonatal intensive care.

METHODS

We collected retrospectively seventeen EEG recordings (15 babies, conceptional age 26-33weeks, no brain lesions) that were divided into groups according to drug administration at the time of EEG: phenobarbital, fentanyl, theophylline, and controls. SATs were extracted from the EEG for further analysis with several advanced time-series analysis paradigms.

RESULTS

The visual appearance of SATs was unaffected by drugs. Phenobarbital reduced the total power of the SAT events. Both fentanyl and phenobarbital reduced the length of SATs, and enhanced the oscillations at higher frequencies. Theophylline reduced the oscillatory activity at middle frequencies during SAT, but enhanced oscillations at higher frequencies during time-period prior to SAT.

CONCLUSIONS

Our findings suggest, that (i) all drugs examined affect brain activity in ways that are not seen in the visual EEG interpretation, and that (ii) both acute and long term (i.e. developmental) effects of these drugs on brain may warrant more attention as a part of optimizing preterm neurological care.

Bench to cribside: the path for developing a neuroprotectant

The consequences of perinatal brain injury include immeasurable anguish for families and substantial ongoing costs for care and support of effected children. Factors associated with perinatal brain injury in the preterm infant include inflammation and infection, and with increasing gestational age, a higher proportion is related to hypoxic-ischemic events, such as stroke and placental abruption. Over the past decade, we have acquired new insights in the mechanisms underpinning injury and many new tools to monitor outcome in perinatal brain injury in our experimental models. By embracing these new technologies, we can expedite the screening of novel therapies. This is critical as despite enormous efforts of the research community, hypothermia is the only viable neurotherapeutic, and this procedure is limited to term birth and postcardiac arrest hypoxic-ischemic events. Importantly, experimental and preliminary data in humans also indicate a considerable therapeutic potential for melatonin against perinatal brain injury. However, even if this suggested potential is proven, the complexity of the human condition means we are likely to need additional neuroprotective and regenerative strategies. Thus, within this review, we will outline what we consider the key stages of preclinical testing and development for a neuroprotectant or regenerative neurotherapy for perinatal brain injury. We will also highlight examples of novel small animal physiological and behavioral testing that gives small animal preclinical models greater clinical relevance. We hope these new tools and an integrated bench to cribside strategic plan will facilitate the fulfillment of our overarching goal, improving the long-term brain health and quality of life for infants suffering perinatal brain injury.

Neuroprotective effects of the sigma-1 receptor ligand PRE-084 against excitotoxic perinatal brain injury in newborn mice

Excessive glutamate release followed by N-methyl-D-aspartate receptor (NMDAR) activation plays a crucial role in perinatal brain injury. We have previously shown that dextromethorphan, a low-affinity NMDAR antagonist with anti-inflammatory properties, is neuroprotective against neonatal excitotoxic brain injury. Of interest, dextromethorphan is also a sigma-1 receptor (σ1R) agonist. The pharmacologic class of σ1R agonists has yielded propitious results in various animal models of adult central nervous system pathology. In an established neonatal mouse model of excitotoxic brain injury, we evaluated the effect of the selective σ1R agonist 2-(4-morpholinethyl) 1-phenylcyclohexanecarboxylate (PRE-084). A single intraperitoneal injection of 0.1 μg/g (low dose) or 10 μg/g (high dose) bodyweight (bw) PRE-084, given 1h after the excitotoxic insult, significantly reduced lesion size in cortical gray matter 24 h and 120 h after the insult. Repetitive injections of 0.1 μg/g PRE-084 proved to be equally effective. PRE-084 treatment resulted in a decrease in cell death indicated by reduced TUNEL positivity and caspase-3 activation. Furthermore, it lowered the number of isolectin B4-positive, activated microglial cells. PRE-084 had no effect on developmental apoptosis in the undamaged brain. In vitro findings in primary hippocampal neurons suggest that PRE-084 treatment provides partial protection against glutamate induced morphological and functional changes. For excitotoxicity as playing a crucial role in the pathogenesis of perinatal brain injury, we demonstrate for the first time that systemic treatment with the highly selective σ1R agonist PRE-084 protects against NMDAR-mediated excitotoxic brain damage.

The Vermont Oxford Neonatal Encephalopathy Registry: rationale, methods, and initial results

Background

In 2006, the Vermont Oxford Network (VON) established the Neonatal Encephalopathy Registry (NER) to characterize infants born with neonatal encephalopathy, describe evaluations and medical treatments, monitor hypothermic therapy (HT) dissemination, define clinical research questions, and identify opportunities for improved care.

Methods

Eligible infants were ≥ 36 weeks with seizures, altered consciousness (stupor, coma) during the first 72 hours of life, a 5 minute Apgar score of ≤ 3, or receiving HT. Infants with central nervous system birth defects were excluded.

Results

From 2006–2010, 95 centers registered 4232 infants. Of those, 59% suffered a seizure, 50% had a 5 minute Apgar score of ≤ 3, 38% received HT, and 18% had stupor/coma documented on neurologic exam. Some infants experienced more than one eligibility criterion. Only 53% had a cord gas obtained and only 63% had a blood gas obtained within 24 hours of birth, important components for determining HT eligibility. Sixty-four percent received ventilator support, 65% received anticonvulsants, 66% had a head MRI, 23% had a cranial CT, 67% had a full channel encephalogram (EEG) and 33% amplitude integrated EEG. Of all infants, 87% survived.

Conclusions

The VON NER describes the heterogeneous population of infants with NE, the subset that received HT, their patterns of care, and outcomes. The optimal routine care of infants with neonatal encephalopathy is unknown. The registry method is well suited to identify opportunities for improvement in the care of infants affected by NE and study interventions such as HT as they are implemented in clinical practice.

Neuroanatomical consequences of very preterm birth in middle childhood

Individuals born preterm can demonstrate reductions in brain volume, cortical surface area and thickness. However, the extent of these neuroanatomical deficits and the relation among these measures in middle childhood, a critical developmental period, have not been determined. We assessed differences in brain structure by acquiring high-resolution T(1)-weighted scans in 25 children born very preterm (<32 weeks gestational age) without significant post-natal neurological sequelae and 32 age-matched term-born children (7-10 years). Children born very preterm had decreased brain volume, surface area and cortical thickness compared to term-born children. Furthermore, children born preterm did not display the robust relation between total brain volume and basal ganglia and thalamic volume apparent in the term-born children. Cortical thickness analyses revealed that the cortex was thinner for children born preterm than term-born children in the anterior cingulate cortex/supplementary motor area, isthmus of the cingulate gyrus, right superior temporal sulcus, right anterior insula, postcentral gyrus and precuneus. Follow-up analyses revealed that right precuneus thickness was correlated with gestational age. Thus, even without significant postnatal medical sequelae, very preterm-born children showed atypical brain structure and developmental patterns in areas related to higher cognitive function. Disruptions of the typical neurodevelopmental trajectory in the third trimester of pregnancy likely underlie these differences persisting into middle childhood.

"New-generation" pulse oximeters in extremely low-birth-weight infants: how do they perform in clinical practice?

The aim of this study was to evaluate the performance of "new-generation" pulse oximeters in extremely low-birth-weight ([ELBW] ≤ 1000 g) infants. In a prospective crossover observational study, the performance of pulse oximeters of 3 brands (Masimo, Nellcor, and Philips) was evaluated by dual SpO2 measurement in ELBW infants. Disposable probes of either equal or different brands were placed around both feet of the patient simultaneously for approximately 4 hours. Probes were switched between feet every hour. Absolute differences in SpO2 values (ΔSpO2) and the bias between brands were studied. Nine ELWB infants were included (gestational age: mean ± SD = 26(3)/7 ± 1 4/7 weeks). The median (range) ΔSpO2 was 2% (0%-26%). In 9% of the time, ΔSpO2 was 5% or more. The variance of the difference of the 3 pulse oximeter brands was not significantly different. No consequent bias between brands was found. Simultaneously obtained pulse oximeter measurements from the feet of ELBW infants differ from each other. Our results suggest that it is not the brand but the handling of the pulse oximeter in clinical practice, such as the place and positioning of the probe, that influences the performance of the pulse oximeter the most. Improvement in the accuracy of oxygen-monitoring techniques for ELBW infants is required.

Developmental care for high-risk newborns: emerging science, clinical application, and continuity from newborn intensive care unit to community

Neonatology has optimized medical outcomes for high-risk newborns yet neurodevelopmental outcomes continue to be a concern. Basic science, clinical research, and environmental design perspectives have shown the impact of the caregiving environment on the developing brain and the role of professional caregivers in providing supportive intervention to both infants and their families. This recognition has prompted a focus on early developmentally supportive care (DSC) for high-risk newborns both in the hospital and in community follow up. DSC has emerged as a recognized standard of care in most neonatal intensive care units. Still, many questions remain and much integrative research is needed.

The integrated development of sensory organization

The natural environment provides a flux of concurrent stimulation to all our senses, and the integration of information from different sensory systems is a fundamental feature of perception and cognition. How information from the different senses is integrated has long been of concern to several scientific disciplines, including psychology, cognitive science, and the neurosciences, each with different questions and methodologies. In this article, I briefly explore some of these recent advances in the understanding of the development of sensory integration and organization and discuss implications of these advances for the care and management of the preterm infant.

Neonatal intensive care practices harmful to the developing brain

There has been a marked increase in the survival of extremely low birth weight (ELBW) infants, but these babies have a long stay in the NICU. Strategies to decrease their neurodevelopmental impairment become very important. The maximum development of the brain occurs between 29-41 weeks. From the warm, dark, acquatic econiche, where the baby hears pleasant sounds like the mother's heart beat, the baby suddenly finds itself in the dry, cold, excessively bright, noisy, environment of the NICU. Noise, bright light, painful procedures, and ill-timed caregiving activities, adversely affect the infant's development. Excessive radiation from X-rays of babies on the ventilator and CT scans also affect the brain. Medications like steroids for chronic lung disease also cause damage to the brain. Aminoglycides and frusemide are known to cause hearing impairment. Hence a developmentally supportive, humanized care will go a long way in enhancing the developmental outcome of these babies.

Maturational changes in automated EEG spectral power analysis in preterm infants

Our study aimed at automated power spectral analysis of the EEG in preterm infants to identify changes of spectral measures with maturation. Weekly (10-20 montage) 4-h EEG recordings were performed in 18 preterm infants with GA <32 wk and normal neurological follow-up at 2 y, resulting in 79 recordings studied from 27(+4) to 36(+3) wk of postmenstrual age (PMA, GA + postnatal age). Automated spectral analysis was performed on 4-h EEG recordings. The frequency spectrum was divided in delta 1 (0.5-1 Hz), delta 2 (1-4 Hz), theta (4-8 Hz), alpha (8-13 Hz), and beta (13-30 Hz) band. Absolute and relative power of each frequency band and spectral edge frequency were calculated. Maturational changes in spectral measures were observed most clearly in the centrotemporal channels. With advancing PMA, absolute powers of delta 1 to 2 and theta decreased. With advancing PMA, relative power of delta 1 decreased and relative powers of alpha and beta increased, respectively. In conclusion, with maturation, spectral analysis of the EEG showed a significant shift from the lower to the higher frequencies. Computer analysis of EEG will allow an objective and reproducible analysis for long-term prognosis and/or stratification of clinical treatment.

The effects of closed tracheal suctioning plus volume guarantee on cerebral hemodynamics

OBJECTIVE

To compare the effects of open tracheal suctioning (OS) plus intermittent mandatory ventilation (IMV) vs. closed tracheal suctioning (CS) plus volume guarantee ventilation (VG) on changes in mean cerebral blood-flow velocity (CBFv) of ventilated very low birth weight (VLBW) infants.

STUDY DESIGN

A total of 75 normotensive, ventilated VLBW infants (with normal cranial ultrasounds) had monitoring of mean CBFv, PCO2 and mean arterial blood pressure (MABP) before, during and after 220 tracheal suctioning sessions during the first week of life. Multiple linear regression analysis was used to determine the factor(s) influencing the magnitude of relative changes from baseline in mean CBFv after suctioning.

RESULT

In all, 49 VLBW infants receiving IMV had monitoring during 124 OS sessions between July 2002 and May 2005; 26 VLBW infants receiving VG had monitoring during 96 CS sessions between January 2006 and July 2007. The average magnitude of relative changes in mean CBFv was significantly less with CS+VG, and was associated with the magnitude of relative changes in PCO2 and suctioning-ventilator group.

CONCLUSION

The average magnitude of relative changes in mean CBFv was reduced in VLBW infants with CS+VG vs. OS+IMV.

Effects of preterm birth on cortical thickness measured in adolescence

Despite the extensive research into brain development after preterm birth, few studies have investigated its long-term effects on cortical thickness. The Stockholm Neonatal Project included infants between 1988 and 1993 with birth weight (BW) ≤ 1500 g. Using a previously published method, cortical thickness was estimated on T(1)-weighted 3D anatomical images acquired from 74 ex-preterm and 69 term-born adolescents (mean age 14.92 years). The cortex was significantly thinner in ex-preterm individuals in focal regions of the temporal and parietal cortices as indicated by voxel-wise t-tests. In addition, large regions around the central sulcus and temporal lobe as well as parts of the frontal and occipital lobes tended also to be thinner in the ex-preterm group. Although these results were not significant on voxel-wise tests, the spatially coherent arrangement of the thinning in ex-preterm individuals made it notable. When the group of ex-preterm individuals was divided by gestational age or BW, the thinning tended to be more pronounced in the anterior and posterior poles in those born nearer term or with a BW closer to 1500 g. These results support the notion that preterm birth is a risk factor for long-term development of cortical thickness.

Oxygen use for preterm infants: factors that may influence clinical decisions surrounding oxygen titration

Preterm infants in neonatal intensive care units frequently require oxygen therapy. Clinicians are responsible for titrating oxygen to maximize the benefits and minimize the risks of this therapy. Studies have identified various toxic effects of oxygen on the developing tissues of the preterm infant; however, optimal target SpO(2) ranges have not been identified. Current trends in neonatology are focusing on defining optimal oxygen saturation ranges to improve infant outcomes and to decrease complications associated with the oxygen use. Consequently, research-based guidelines are being developed in neonatal intensive care units to guide oxygen administration. As target oxygen saturation ranges are developed, issues regarding health care professional compliance with these ranges have been identified. The specific reasons for this noncompliance have not been widely explored. However, factors such as nursing shortages, staffing issues, and a de-emphasis on staff education surrounding oxygen use have been offered as possible reasons. Understanding factors shaping clinical decision-making about oxygen titration is critical when designing policies and educational programs to change oxygen titration practice and ultimately improve patient outcomes. In this article, the literature outlining the importance of oxygen titration for preterm infants is reviewed. Discussion then focuses on factors that influence clinical decision-making and how these factors may influence decisions surrounding the use of oxygen for preterm infants.

Parental liminality: a way of understanding the early experiences of parents who have a very preterm infant

AIM

The aim of this study was to explore the early experiences of parents who have a very preterm infant.

BACKGROUND

Very preterm infants are physiologically ill-prepared for extra-uterine life, but a greater number now survive birth and the postnatal period. The complex needs of the very preterm infant are met in the technological environment of the neonatal intensive care area, separating parents, physically and psychologically from their very preterm infant. Studies exploring the parental experience have identified parental stress; lowly parental status and attachment issues as areas of concern. However, there is little understanding about the early parental experience.

DESIGN

This study used a phenomenological interpretive design.

METHODS

Ethical approval to conduct this study using two study centres was obtained. An interpretive interactionist approach guided this study. Data were collected from three sources: 20 parents of very preterm infants, five senior neonatal nurses and seven neonatal intensive care nurses. Purposive sampling was used for the first and second sources, and data were collected through semi-structured interviews. The third source of data occurred opportunistically through one focus group.

ANALYSIS

Analysis involved constant comparative analysis.

RESULTS

Crisis, uncertainty and powerlessness, properties of liminality framed this early complex parental transition. It is argued that the overarching theme of parental liminality best framed the parental physical, psychological and social experiences.

CONCLUSION

This qualitative interpretive study identified that parents of very preterm infants experienced many crises, uncertainty and powerlessness in their transition to parenthood, making them liminal people.

RELEVANCE TO CLINICAL PRACTICE

Parental liminality provides a means of conceptualising the early experiences of parents of very preterm infants, providing practitioners, at strategic and operational levels, with the means of developing supporting interventions in the early stages of transition for parents of very preterm infants. Such support could mediate parent-infant relationships.

Inflammation processes in perinatal brain damage

Once viewed as an isolated, immune-privileged organ, the central nervous system has undergone a conceptual change. Neuroinflammation has moved into the focus of research work regarding pathomechanisms underlying perinatal brain damage. In this review, we provide an overview of current concepts regarding perinatal brain damage and the role of inflammation in the disease pathomechanism.

Structural correlates of preterm birth in the adolescent brain

OBJECTIVE

The Stockholm Neonatal Project involves a prospective, cross-sectional, population-based, cohort monitored for 12 to 17 years after birth; it was started with the aim of investigating the long-term structural correlates of preterm birth and comparing findings with reports on similar cohorts.

METHODS

High-resolution anatomic and diffusion tensor imaging data measuring diffusion in 30 directions were collected by using a 1.5-T MRI scanner. A total of 143 adolescents (12.18-17.7 years of age) participated in the study, including 74 formerly preterm infants with birth weights of <or=1500 g (range: 645-1486 g) and 69 term control subjects. The 2 groups were well matched with respect to demographic and socioeconomic data. The anatomic MRI data were used for calculation of total brain volumes and voxelwise comparison of gray matter (GM) volumes. The diffusion tensor imaging data were used for voxelwise comparison of white matter (WM) microstructural integrity.

RESULTS

The formerly preterm individuals possessed 8.8% smaller GM volume and 9.4% smaller WM volume. The GM and WM volumes of individuals depended on gestational age and birth weight. The reduction in GM could be attributed bilaterally to the temporal lobes, central, prefrontal, orbitofrontal, and parietal cortices, caudate nuclei, hippocampi, and thalami. Lower fractional anisotropy was observed in the posterior corpus callosum, fornix, and external capsules.

CONCLUSIONS

Although preterm birth was found to be a risk factor regarding long-term structural brain development, the outcome was milder than in previous reports. This may be attributable to differences in social structure and neonatal care practices.

The Golden Hour: care of the LBW infant during the first hour of life one unit's experience

Care practices during the first hour of life, the Golden Hour, can have a significant impact on outcomes of low birth weight infants. Although the latest edition of the Neonatal Resuscitation Program added guidelines for preterm infants, additional care is often indicated. Complications that could potentially be impacted by care in the first hour of life include thermoregulation, intraventricular hemorrhage, chronic lung disease, and retinopathy of prematurity. Our unit has implemented and revised a Golden Hour evidence-based care process that includes the use of realistic videotaped simulations, followed by team debriefing sessions. Early results of the revised process show reductions in the targeted complications.

From selective vulnerability to connectivity: insights from newborn brain imaging

The ability to image the newborn brain during development has provided new information regarding the effects of injury on brain development at different vulnerable time periods. Studies in animal models of brain injury correlate beautifully with what is now observed in the human newborn. We now know that injury at term primarily results in grey matter injury while injury in the premature brain predominantly results in a pattern of white matter injury, though recent evidence suggests a blurring of this distinction . These injuries affect how the brain matures subsequently and again, imaging has led to new insights that allow us to match function and structure. This review will focus on these patterns of injury that are so crucially determined by age at insult. In addition, this review will highlight how the brain responds to these insults with changes in connectivity that have profound functional consequences.

High incidence of thyroid dysfunction in preterm infants

To determine the validity of a repeat thyroid function test for preterm infants, and to investigate factors that influence thyroid function of preterm infants, thyroid functions of 105 infants born at <32 weeks' gestational age were evaluated. Initial serum free thyroxine (fT4) and thyrotropin (TSH) levels were measured during the first 10 days of life, and repeated tests were performed more than 2 weeks apart. We analyzed the effects of gestational age, systemic diseases, and nutrition on the development of thyroid dysfunction. Thirty-one infants (30%) had low fT4 levels (<0.7 ng/dL) in the absence of elevated TSH levels (<7 microU/mL). Thirteen infants (12%) had hypothyroidism (fT4 <0.7 ng/dL, TSH >or=10 microU/mL) and mean age at diagnosis was 28+/-17 days. Twelve infants had moderately elevated TSH (TSH 10-30 microU/mL) with normal fT4 levels after 1 week of postnatal life. The history of undergone surgical procedure which needed iodine containing disinfectants was significantly frequent in the infant with hypothyroidism and transient TSH elevation. Repeated thyroid function tests are necessary for preterm infants, even though they initially show normal thyroid function, and are especially important for infants who have been exposed to excessive or insufficient levels of iodine.

Cerebral MRI findings in a cohort of ex-preterm and control adolescents

AIM

Newborn infants were entered between 1988 and 1993 into a prospective, long-term, follow-up study. We aimed to investigate how the outcome of preterm-born individuals on cerebral magnetic resonance imaging (MRI) compared to that reported on similar cohorts internationally.

METHODS

The 74 ex-preterm (12.38-17.7 years, 51% girls) and 69 control participants (12.18-16.47 years, 53% girls) underwent a MRI examination on a 1.5T scanner. Two experienced neuroradiologists examined the T1- and T2-weighted images first independently and then in consensus without knowledge of group adherence.

RESULTS

Only 21 (4 controls) of the 143 sets of scans showed any abnormalities. All but one of these were of mild extent. Among the ex-preterm adolescents two showed only incidental findings while the other 15 had either gliosis or white matter loss. Eleven subjects had white matter loss, seven of which had no other abnormalities. Four subjects had gliosis, three of which had no other abnormalities. The extent, severity or frequency of injury was not related to being born small for gestational age.

CONCLUSION

Although the rate of structural abnormalities was higher in the group of adolescents born preterm, this rate was well below that reported from other centres around the world. We attribute this to the minimally invasive neonatal care and to different social structures in Sweden compared to that of other reports on similar cohorts.

The effect of feeding experience on clinical outcomes in preterm infants

OBJECTIVE

The purpose of this analysis was to investigate the effect of oral feeding experience on clinical outcomes (time to full oral feedings and length of stay) in preterm infants.

STUDY DESIGN

This analysis was completed on 92 infants who participated in a longitudinal, non-experimental study. Data were collected daily for maturity, weight and experience at oral feeding. Additional data were collected to assess overall morbidity.

RESULT

Time to full oral feedings was predicted by experience at oral feeding and morbidity. Length of stay from the start of oral feedings until discharge was predicted by feeding experience and by maturity at the first oral feeding. Weight gain was not affected by feeding experience.

CONCLUSION

Experience at feeding may result in more rapid transition to full oral feedings regardless of severity of illness and may contribute to shorter length of stay. These positive clinical outcomes related to feeding experience warrant further research attention.

Adverse neurodevelopment in preterm infants with postnatal sepsis or necrotizing enterocolitis is mediated by white matter abnormalities on magnetic resonance imaging at term

OBJECTIVES

To test the hypothesis that the impact of postnatal sepsis/necrotizing enterocolitis (NEC) on neurodevelopment may be mediated by white matter abnormality (WMA), which can be demonstrated with magnetic resonance imaging (MRI).

STUDY DESIGN

A prospective cohort of 192 unselected preterm infants (gestational age <30 weeks), who were evaluated for sepsis and NEC, underwent imaging at term-equivalent age and neurodevelopmental outcome at 2 years corrected age with the Bayley Scales of Infant Development.

RESULTS

Sixty-eight preterm (35%) infants had 100 episodes of confirmed sepsis, and 9 (5%) infants had confirmed NEC. Coagulase-negative staphylococci accounted for 73% (73/100) of the episodes of confirmed sepsis. Infants with sepsis/NEC had significantly more WMA on MRI at term compared with infants in the no-sepsis/NEC group. They also had poorer psychomotor development that persisted after adjusting for potential confounders but which became nonsignificant after adjusting for WMA.

CONCLUSIONS

Preterm infants with sepsis/NEC are at greater risk of motor impairment at 2 years, which appears to be mediated by WMA. These findings may assist in defining a neuroprotective target in preterm infants with sepsis/NEC.

Clinical practices in neonatal oxygenation: where have we failed? What can we do?

INTRODUCTION

Oxygen is among the most frequently used therapies in neonates worldwide. Nevertheless, many times it is used unnecessarily. Neonatal practices have changed over the last several years; treatments originally believed to be beneficial have been discarded.

STUDY DESIGN

Oxygen utilized 'just in case' or 'prophylactically' can lead to great damage previously ignored and/or unseen by healthcare providers. It is imperative to improve education on neonatal oxygenation and saturation monitoring. It is also important not to depend on old assumptions, which were not based on evidences. The potential for unseen damage at the cellular and tissue levels cannot be ignored. Therapies that prove to be outdated or even dangerous must be eliminated while further research and confirmation of the best practices are determined. Freedom to choose can come at a price.

Tracheal suctioning is associated with prolonged disturbances of cerebral hemodynamics in very low birth weight infants

OBJECTIVES

Examining the effects of tracheal suctioning on cerebral hemodynamics of normotensive ventilated very low birth weight (VLBW) infants with normal cranial ultrasounds; determining the factor(s) influencing changes in mean cerebral blood flow velocity (CBFv) after suctioning.

METHODS

Seventy-three VLBW infants had continuous monitoring of mean arterial blood pressure (MABP), PaCO(2), PaO(2) and mean CBFv before, during, and after 202 suctioning sessions during the first week of life. Peak (or nadir) and relative changes of the four variables for 45 min after suctioning were calculated. Multiple linear regression was used to determine the factor(s) influencing changes in mean CBFv after suctioning.

RESULT

Birth weight was 928+/-244 g; gestational age was 27.0+/-2.0 weeks. Mean CBFv increased to 31.0+/-26.4% after suctioning and remained elevated for 25 min. PaCO(2) was highly associated with mean CBFv (P<0.001), whereas MABP and PaO(2) were not.

CONCLUSION

We observed prolonged increases of mean CBFv following suctioning in ventilated VLBW infants that were previously unrecognized. This is concerning since disturbances of CBF may be associated with subsequent brain injury.

Non-pharmacological techniques for pain management in neonates

Significant progress in understanding the physiology, clinical correlates, and consequences of neonatal pain have resulted in greater attention to pain management during neonatal intensive care. A number of nonpharmacological therapies have been investigated, including nonnutritive sucking, with and without sucrose use, swaddling or facilitated tucking, kangaroo care, music therapy, and multi-sensorial stimulation. Although the efficacy of these approaches is clearly evident, they cannot provide analgesia for moderate or severe pain in the neonate. Further, some of these therapies cannot be effectively applied to all populations of critically ill neonates. Acupuncture, an ancient practice in Chinese medicine, has gained increasing popularity for symptom control among adults and older children. Acupuncture may provide an effective nonpharmacological approach for the treatment of pain in neonates, even moderate or severe pain, and should be considered for inclusion in a graduated multidisciplinary algorithm for neonatal pain management.

Corticosteroids in perinatal medicine: how to improve outcomes without affecting the developing brain?

Antenatal glucocorticoid therapy remains one of the most striking successes in the perinatal management of complicated pregnancies that result in premature birth. The anti-inflammatory and maturative properties of fluorocorticoids are such that all women at risk of preterm delivery before 34weeks gestation should be treated. Betamethasone is preferred to dexamethasone and no more than two courses, 2weeks apart, should be given until the evidence from further controlled trials on repeated doses becomes available. In particular, the early use of postnatal dexamethasone should be avoided in preterm infants because of the deleterious effects on neurological development, including not only cerebral palsy but also cognitive function and psychiatric-related behavior. Treatment with other steroids should be restricted to the context of randomized controlled trials.

Concordance between school outcomes and developmental follow-up results of very preterm and/or low birth weight children at the age of 5 years

INTRODUCTION

Long-term follow-up studies have revealed a high frequency of developmental disturbances in preterm survivors of neonatal intensive care who were formerly considered to be non-disabled. These developmental disturbances interfere with the acquisition of everyday skills and, in particular, with normal school functioning.

METHODS

Developmental and school outcomes of 355 children, age 5 years at the time of the study, who had a mean gestational age of 30.2 weeks (SD: 1.95) and a mean birth weight of 1272 g (SD: 326) were investigated. Children with severe handicaps were excluded from the study. Perinatal data, information from a parental and school questionnaire and data from standardized developmental tests were used to explain the differences.

RESULTS

An agreement of 72% was found between developmental follow-up and school outcomes. Normal developmental results but problematic school outcomes were found for 15% of the children tested. There were more boys than girls in this latter group as well as small-for-gestational-age children with relatively poor motor or language development. The schools had not identified problems in 13% of the children, whereas their developmental outcomes were problematic. These children had less neonatal morbidity and relatively higher IQ's than children who also had problematic developmental outcomes but who had been signalled as problematic by their schools.

CONCLUSIONS

Schools have a good insight in the school functioning of children who are developing well and of children with the lowest developmental scores and the most complicated neonatal histories. How school and developmental outcomes interrelate in the in-between groups remains a challenging question that could be answered by following these children throughout their school career.

Treatment-by-gender effect when aiming to avoid hyperoxia in preterm infants in the NICU

OBJECTIVE

To examine gender-specific differences in response to the O(2) saturation (SpO(2)) targets aimed at avoiding hyperoxia in very low birth weight infants (VLBW).

METHODS

Analysis of a prospectively collected database of all infants </=1250 g in two perinatal centres. A change was instituted in January 2003 with the objective of avoiding hyperoxia with target SpO(2) at 85-93% (period II). Prior to this, SpO(2) high alarms were set at 100% and low alarms at 92% (period I; from January 2000 to December 2002).

RESULTS

Of the 497 infants that met enrolment criteria, 297 (60%) were born during period I and 140 (47%) of them were male. During period II, 200 infants were born and 101 (50%) were male. Analysis by gender showed that the rate of retinopathy of prematurity, bronchopulmonary dysplasia and length of stay is significantly better for female infants than males on period II compared to period I. Neither gender experienced increased short-term neurological morbidity in response to lower SpO(2) targets.

CONCLUSIONS

There is a significant gender-specific difference favouring females in the beneficial effects produced by avoiding high SpO(2) and hyperoxia, with no difference in the distribution of any potential short-term detrimental effects.

Oxygen as a neonatal health hazard: call for détente in clinical practice

Education in oxygenation and in how oxygen is given to newborns needs to increase. Treatment with oxygen should no longer be considered proverbial and customary, regardless of our 'past experience' or consensus recommendations in clinical guidelines, since oxygen may lead to acute or chronic health effects.

CONCLUSION

Inappropriate oxygen use is a neonatal health hazard associated with aging, DNA damage and cancer, retinopathy of prematurity, injury to the developing brain, infection and others. Neonatal exposure to pure O2, even if brief, or to pulse oximetry >95% when breathing supplemental O2 must be avoided as much as possible.