A systematic review of immune-based interventions for perinatal neuroprotection: closing the gap between animal studies and human trials

BACKGROUND

Perinatal infection/inflammation is associated with a high risk for neurological injury and neurodevelopmental impairment after birth. Despite a growing preclinical evidence base, anti-inflammatory interventions have not been established in clinical practice, partly because of the range of potential targets. We therefore systematically reviewed preclinical studies of immunomodulation to improve neurological outcomes in the perinatal brain and assessed their therapeutic potential.

METHODS

We reviewed relevant studies published from January 2012 to July 2023 using PubMed, Medline (OvidSP) and EMBASE databases. Studies were assessed for risk of bias using the SYRCLE risk of bias assessment tool (PROSPERO; registration number CRD42023395690).

RESULTS

Forty preclinical publications using 12 models of perinatal neuroinflammation were identified and divided into 59 individual studies. Twenty-seven anti-inflammatory agents in 19 categories were investigated. Forty-five (76%) of 59 studies reported neuroprotection, from all 19 categories of therapeutics. Notably, 10/10 (100%) studies investigating anti-interleukin (IL)-1 therapies reported improved outcome, whereas half of the studies using corticosteroids (5/10; 50%) reported no improvement or worse outcomes with treatment. Most studies (49/59, 83%) did not control core body temperature (a known potential confounder), and 25 of 59 studies (42%) did not report the sex of subjects. Many studies did not clearly state whether they controlled for potential study bias.

CONCLUSION

Anti-inflammatory therapies are promising candidates for treatment or even prevention of perinatal brain injury. Our analysis highlights key knowledge gaps and opportunities to improve preclinical study design that must be addressed to support clinical translation.

Ganaxolone versus Phenobarbital for Neonatal Seizure Management

OBJECTIVE

Seizures are more common in the neonatal period than at any other stage of life. Phenobarbital is the first-line treatment for neonatal seizures and is at best effective in approximately 50% of babies, but may contribute to neuronal injury. Here, we assessed the efficacy of phenobarbital versus the synthetic neurosteroid, ganaxolone, to moderate seizure activity and neuropathology in neonatal lambs exposed to perinatal asphyxia.

METHODS

Asphyxia was induced via umbilical cord occlusion in term lambs at birth. Lambs were treated with ganaxolone (5mg/kg/bolus then 5mg/kg/day for 2 days) or phenobarbital (20mg/kg/bolus then 5mg/kg/day for 2 days) at 6 hours. Abnormal brain activity was classified as stereotypic evolving (SE) seizures, epileptiform discharges (EDs), and epileptiform transients (ETs) using continuous amplitude-integrated electroencephalographic recordings. At 48 hours, lambs were euthanized for brain pathology.

RESULTS

Asphyxia caused abnormal brain activity, including SE seizures that peaked at 18 to 20 hours, EDs, and ETs, and induced neuronal degeneration and neuroinflammation. Ganaxolone treatment was associated with an 86.4% reduction in the number of seizures compared to the asphyxia group. The total seizure duration in the asphyxia+ganaxolone group was less than the untreated asphyxia group. There was no difference in the number of SE seizures between the asphyxia and asphyxia+phenobarbital groups or duration of SE seizures. Ganaxolone treatment, but not phenobarbital, reduced neuronal degeneration within hippocampal CA1 and CA3 regions, and cortical neurons, and ganaxolone reduced neuroinflammation within the thalamus.

INTERPRETATION

Ganaxolone provided better seizure control than phenobarbital in this perinatal asphyxia model and was neuroprotective for the newborn brain, affording a new therapeutic opportunity for treatment of neonatal seizures. ANN NEUROL 2022;92:1066-1079.

Brain White Matter Development Over the First 13 Years in Very Preterm and Typically Developing Children Based on the T 1-w/T 2-w Ratio

BACKGROUND AND OBJECTIVES

To investigate brain regional white matter development in full-term (FT) and very preterm (VP) children at term equivalent and 7 and 13 years of age based on the ratio of T ₁- and T ₂-weighted MRI (T ₁-w/T ₂-w), including (1) whether longitudinal changes differ between birth groups or sexes, (2) associations with perinatal risk factors in VP children, and (3) relationships with neurodevelopmental outcomes at 13 years.

METHODS

Prospective longitudinal cohort study of VP (born <30 weeks' gestation or <1,250 g) and FT infants born between 2001 and 2004 and followed up at term equivalent and 7 and 13 years of age, including MRI studies and neurodevelopmental assessments. T ₁-w/T ₂-w images were parcellated into 48 white matter regions of interest.

RESULTS

Of 224 VP participants and 76 FT participants, 197 VP and 55 FT participants had useable T ₁-w/T ₂-w data from at least one timepoint. T ₁-w/T ₂-w values increased between term equivalent and 13 years of age, with little evidence that longitudinal changes varied between birth groups or sexes. VP birth, neonatal brain abnormalities, being small for gestational age, and postnatal infection were associated with reduced regional T ₁-w/T ₂-w values in childhood and adolescence. Increased T ₁-w/T ₂-w values across the white matter at 13 years were associated with better motor and working memory function for all children. Within the FT group only, larger increases in T ₁-w/T ₂-w values from term equivalent to 7 years were associated with poorer attention and executive function, and higher T ₁-w/T ₂-w values at 7 years were associated with poorer mathematics performance.

DISCUSSION

VP birth and multiple known perinatal risk factors are associated with long-term reductions in the T ₁-w/T ₂-w ratio in white matter regions in childhood and adolescence, which may relate to alterations in microstructure and myelin content. Increased T ₁-w/T ₂-w ratio at 13 years appeared to be associated with better motor and working memory function and there appeared to be developmental differences between VP and FT children in the associations for attention, executive functioning, and mathematics performance.

Preventing harm: A balance measure for improving the detection of fetal growth restriction

BACKGROUND

Increasing the detection of fetal growth restriction (FGR), while reducing stillbirth, also leads to unnecessary early intervention, and associated morbidity, for normally grown babies who are incorrectly suspected of FGR.

AIMS

We sought to design a balance measure that addresses the specificity of FGR detection.

METHODS

A retrospective cohort study on all singleton births ≥32 weeks gestation in 2016 and 2017 in Victoria. We compared two balance measures for the detection of FGR, defined as the proportion of all babies iatrogenically delivered before 39 weeks gestation for suspected FGR that had a birthweight ≥10th centile (balance measure 1) or ≥25th centile (balance measure 2). Hospital level performance on each balance measure was derived and compared to an existing performance measure for severe FGR detection in Victoria.

RESULTS

Of the 38 hospitals analysed, 12 (32%) had a favourable performance on an existing indicator of FGR detection, seven (18%) hospitals had a favourable performance on balance measure 1, and 15 (39%) had a favourable performance on balance measure 2. There was a moderate correlation between hospital performance on the existing indicator and on balance measure 1 (r = 0.447, P = 0.005) but not balance measure 2 (r = -0.063, P = 0.71). There was no difference in perinatal mortality between high performing hospitals and low performing hospitals.

CONCLUSION

Introducing a balance measure into routine reporting may bring greater awareness to the unintended harm associated with increased detection of FGR.

The severe epilepsy syndromes of infancy: A population-based study

OBJECTIVE

To study the epilepsy syndromes among the severe epilepsies of infancy and assess their incidence, etiologies, and outcomes.

METHODS

A population-based cohort study was undertaken of severe epilepsies with onset before age 18 months in Victoria, Australia. Two epileptologists reviewed clinical features, seizure videos, and electroencephalograms to diagnose International League Against Epilepsy epilepsy syndromes. Incidence, etiologies, and outcomes at age 2 years were determined.

RESULTS

Seventy-three of 114 (64%) infants fulfilled diagnostic criteria for epilepsy syndromes at presentation, and 16 (14%) had "variants" of epilepsy syndromes in which there was one missing or different feature, or where all classical features had not yet emerged. West syndrome (WS) and "WS-like" epilepsy (infantile spasms without hypsarrhythmia or modified hypsarrhythmia) were the most common syndromes, with a combined incidence of 32.7/100 000 live births/year. The incidence of epilepsy of infancy with migrating focal seizures (EIMFS) was 4.5/100 000 and of early infantile epileptic encephalopathy (EIEE) was 3.6/100 000. Structural etiologies were common in "WS-like" epilepsy (100%), unifocal epilepsy (83%), and WS (39%), whereas single gene disorders predominated in EIMFS, EIEE, and Dravet syndrome. Eighteen (16%) infants died before age 2 years. Development was delayed or borderline in 85 of 96 (89%) survivors, being severe-profound in 40 of 96 (42%). All infants with EIEE or EIMFS had severe-profound delay or were deceased, but only 19 of 64 (30%) infants with WS, "WS-like," or "unifocal epilepsy" had severe-profound delay, and only two of 64 (3%) were deceased.

SIGNIFICANCE

Three quarters of severe epilepsies of infancy could be assigned an epilepsy syndrome or "variant syndrome" at presentation. In this era of genomic testing and advanced brain imaging, diagnosing epilepsy syndromes at presentation remains clinically useful for guiding etiologic investigation, initial treatment, and prognostication.

Defining Target Vancomycin Trough Concentrations for Treating Staphylococcus aureus Infection in Infants Aged 0 to 90 Days

This study analyzes data from a randomized clinical trial in infants 90 days and younger to develop a pharmacokinetic model to aid physicians in maintaining minimum inhibitory concentrations of vancomycin in young infants with Staphylococcus aureus infection.

Neurodevelopmental outcome at 5 years of age after general anaesthesia or awake-regional anaesthesia in infancy (GAS): an international, multicentre, randomised, controlled equivalence trial

BACKGROUND

In laboratory animals, exposure to most general anaesthetics leads to neurotoxicity manifested by neuronal cell death and abnormal behaviour and cognition. Some large human cohort studies have shown an association between general anaesthesia at a young age and subsequent neurodevelopmental deficits, but these studies are prone to bias. Others have found no evidence for an association. We aimed to establish whether general anaesthesia in early infancy affects neurodevelopmental outcomes.

METHODS

In this international, assessor-masked, equivalence, randomised, controlled trial conducted at 28 hospitals in Australia, Italy, the USA, the UK, Canada, the Netherlands, and New Zealand, we recruited infants of less than 60 weeks' postmenstrual age who were born at more than 26 weeks' gestation and were undergoing inguinal herniorrhaphy, without previous exposure to general anaesthesia or risk factors for neurological injury. Patients were randomly assigned (1:1) by use of a web-based randomisation service to receive either awake-regional anaesthetic or sevoflurane-based general anaesthetic. Anaesthetists were aware of group allocation, but individuals administering the neurodevelopmental assessments were not. Parents were informed of their infants group allocation upon request, but were told to mask this information from assessors. The primary outcome measure was full-scale intelligence quotient (FSIQ) on the Wechsler Preschool and Primary Scale of Intelligence, third edition (WPPSI-III), at 5 years of age. The primary analysis was done on a per-protocol basis, adjusted for gestational age at birth and country, with multiple imputation used to account for missing data. An intention-to-treat analysis was also done. A difference in means of 5 points was predefined as the clinical equivalence margin. This completed trial is registered with ANZCTR, number ACTRN12606000441516, and ClinicalTrials.gov, number NCT00756600.

FINDINGS

Between Feb 9, 2007, and Jan 31, 2013, 4023 infants were screened and 722 were randomly allocated: 363 (50%) to the awake-regional anaesthesia group and 359 (50%) to the general anaesthesia group. There were 74 protocol violations in the awake-regional anaesthesia group and two in the general anaesthesia group. Primary outcome data for the per-protocol analysis were obtained from 205 children in the awake-regional anaesthesia group and 242 in the general anaesthesia group. The median duration of general anaesthesia was 54 min (IQR 41-70). The mean FSIQ score was 99·08 (SD 18·35) in the awake-regional anaesthesia group and 98·97 (19·66) in the general anaesthesia group, with a difference in means (awake-regional anaesthesia minus general anaesthesia) of 0·23 (95% CI -2·59 to 3·06), providing strong evidence of equivalence. The results of the intention-to-treat analysis were similar to those of the per-protocol analysis.

INTERPRETATION

Slightly less than 1 h of general anaesthesia in early infancy does not alter neurodevelopmental outcome at age 5 years compared with awake-regional anaesthesia in a predominantly male study population.

FUNDING

US National Institutes of Health, US Food and Drug Administration, Thrasher Research Fund, Australian National Health and Medical Research Council, Health Technologies Assessment-National Institute for Health Research (UK), Australian and New Zealand College of Anaesthetists, Murdoch Children's Research Institute, Canadian Institutes of Health Research, Canadian Anesthesiologists Society, Pfizer Canada, Italian Ministry of Health, Fonds NutsOhra, UK Clinical Research Network, Perth Children's Hospital Foundation, the Stan Perron Charitable Trust, and the Callahan Estate.

Early surgery and neurodevelopmental outcomes of children born extremely preterm

OBJECTIVES

To (1) compare the neurodevelopmental outcomes at 8 years of age of children born extremely preterm (EP) who underwent surgical procedures during the course of their initial hospital admission with those who did not and (2) compare the outcomes across eras, from 1991 to 2005.

DESIGN

Prospective observational cohort studies conducted over three different eras (1991-1992, 1997 and 2005). Surviving EP children, who required surgical intervention during the primary hospitalisation, were assessed for general intelligence (IQ) and neurosensory status at 8 years of age. Major neurosensory disability comprised any of moderate/severe cerebral palsy, IQ less than -2 SD relative to term controls, blindness or deafness.

RESULTS

Overall, 29% (161/546) of survivors had surgery during the newborn period, with similar rates in each era. Follow-up rates at 8 years were high (91%; 499/546), and 17% (86/499) of survivors assessed had a major neurosensory disability. Rates of major neurosensory disability were substantially higher in the surgical group (33%; 52/158) compared with those who did not have surgery (10%; 34/341) (OR 4.28, 95% CI 2.61 to 7.03). Rates of disability in the surgical group did not improve over time. After adjustment for relevant confounders, no specific surgical procedure was associated with increased risk of disability.

IMPLICATIONS AND RELEVANCE

Major neurosensory disability at 8 years was higher in children born EP who underwent surgery during their initial hospital admission compared with those who did not. The rates of major neurosensory disability in the surgical cohort are not improving over time.

Is selective echocardiography in duodenal atresia the future standard of care?

BACKGROUND

Duodenal atresia (DA) is associated with cardiac defects that may have perioperative care implications. Standard preoperative care includes echocardiography to identify such cardiac defects, but this dogma has been challenged. We aimed to assess selective and selective strategies for preoperative echocardiography in DA patients.

METHODS

Single-center retrospective review of neonates with DA over a 16-year period was performed. Data included preoperative cardiovascular and respiratory examination, chest x-ray, and echocardiography. We compared the current nonselective versus selective strategies, limiting preoperative echocardiogram to those in whom: (1) cardiac or respiratory or chest x-ray examination was abnormal, or (2) cardiac or respiratory examination was abnormal. Sensitivity, specificity, positive and negative predictive values were compared with chi-square tests.

RESULTS

Seventy-one of 109 (65%) consecutive neonates with DA underwent preoperative echocardiography according to a nonselective, physician-determined strategy. Forty of 71 (56%) patients had cardiac defects, including 16/40 (27%) major defects. Sixteen additional postoperative echocardiograms revealed 2 missed major defects. In the same cohort, selective strategies would have performed 17-24% fewer echocardiograms without significant detriment in performance.

CONCLUSIONS

All strategies considered missed some major cardiac defects. A selective strategy, determining DA patients not requiring preoperative echocardiogram, could reduce the number of echocardiograms performed without compromising patient safety.

TYPE OF STUDY

Retrospective study.

LEVEL OF EVIDENCE

Level II.

Differences in Blood Pressure in Infants After General Anesthesia Compared to Awake Regional Anesthesia (GAS Study-A Prospective Randomized Trial)

BACKGROUND

The General Anesthesia compared to Spinal anesthesia (GAS) study is a prospective randomized, controlled, multisite, trial designed to assess the influence of general anesthesia (GA) on neurodevelopment at 5 years of age. A secondary aim obtained from the blood pressure data of the GAS trial is to compare rates of intraoperative hypotension after anesthesia and to identify risk factors for intraoperative hypotension.

METHODS

A total of 722 infants ≤60 weeks postmenstrual age undergoing inguinal herniorrhaphy were randomized to either bupivacaine regional anesthesia (RA) or sevoflurane GA. Exclusion criteria included risk factors for adverse neurodevelopmental outcome and infants born at <26 weeks of gestation. Moderate hypotension was defined as mean arterial pressure measurement of <35 mm Hg. Any hypotension was defined as mean arterial pressure of <45 mm Hg. Epochs were defined as 5-minute measurement periods. The primary outcome was any measured hypotension <35 mm Hg from start of anesthesia to leaving the operating room. This analysis is reported primarily as intention to treat (ITT) and secondarily as per protocol.

RESULTS

The relative risk of GA compared with RA predicting any measured hypotension of <35 mm Hg from the start of anesthesia to leaving the operating room was 2.8 (confidence interval [CI], 2.0-4.1; P < .001) by ITT analysis and 4.5 (CI, 2.7-7.4, P < .001) as per protocol analysis. In the GA group, 87% and 49%, and in the RA group, 41% and 16%, exhibited any or moderate hypotension by ITT, respectively. In multivariable modeling, group assignment (GA versus RA), weight at the time of surgery, and minimal intraoperative temperature were risk factors for hypotension. Interventions for hypotension occurred more commonly in the GA group compared with the RA group (relative risk, 2.8, 95% CI, 1.7-4.4 by ITT).

CONCLUSIONS

RA reduces the incidence of hypotension and the chance of intervention to treat it compared with sevoflurane anesthesia in young infants undergoing inguinal hernia repair.

Associations of Newborn Brain Magnetic Resonance Imaging with Long-Term Neurodevelopmental Impairments in Very Preterm Children

OBJECTIVE

To determine the relationship between brain abnormalities on newborn magnetic resonance imaging (MRI) and neurodevelopmental impairment at 7 years of age in very preterm children.

STUDY DESIGN

A total of 223 very preterm infants (<30 weeks of gestation or <1250 g) born at Melbourne's Royal Women's Hospital had a brain MRI scan at term equivalent age. Scans were scored using a standardized system that assessed structural abnormality of cerebral white matter, cortical gray matter, deep gray matter, and cerebellum. Children were assessed at 7 years on measures of general intelligence, motor functioning, academic achievement, and behavior.

RESULTS

One hundred eighty-six very preterm children (83%) had both an MRI at term equivalent age and a 7-year follow-up assessment. Higher global brain, cerebral white matter, and deep gray matter abnormality scores were related to poorer intelligence quotient (IQ) (Ps < .01), spelling (Ps < .05), math computation (Ps < .01), and motor function (Ps < .001). Higher cerebellum abnormality scores were related to poorer IQ (P = .001), math computation (P = .018), and motor outcomes (P = .001). Perinatal, neonatal, and social confounders had little effect on the relationships between the MRI abnormality scores and outcomes. Moderate-severe global abnormality on newborn MRI was associated with a reduction in IQ (-6.9 points), math computation (-7.1 points), and motor (-1.9 points) scores independent of the other potential confounders.

CONCLUSIONS

Structured evaluation of brain MRI at term equivalent is predictive of outcome at 7 years of age, independent of clinical and social factors.

Perioperative risk factors for impaired neurodevelopment after cardiac surgery in early infancy

OBJECTIVE

Historical cohort studies have reported adverse neurodevelopment following cardiac surgery during early infancy. Advances in surgical techniques and perioperative care have coincided with updating of neurodevelopmental assessment tools. We aimed to determine perioperative risk factors for impaired neurodevelopment at 2 years following surgery for congenital heart disease (CHD) in early infancy.

DESIGN AND PATIENTS

We undertook a prospective longitudinal study of 153 full-term infants undergoing surgery for CHD before 2 months of age. Infants were excluded if they had a genetic syndrome associated with neurodevelopmental impairment.

OUTCOME MEASURES

Predefined perioperative parameters were recorded and infants were classified according to cardiac anatomy. At 2 years, survivors were assessed using the Bayley Scales of Infant Development-III.

RESULTS

At 2 years, 130 children (98% of survivors) were assessed. Mean cognitive, language and motor scores were 93.4±13.6, 93.6±16.1 and 96.8±12.5 respectively (100±15 norm). Twenty (13%) died and 12 (9%) survivors had severe impairment (score <70), mostly language (8%). The lowest scores were in infants born with single ventricle physiology with obstruction to the pulmonary circulation who required a neonatal systemic-to-pulmonary artery shunt. Additional risk factors for impairment included reduced gestational age, postoperative elevation of lactate or S100B and repeat cardiac surgery.

CONCLUSIONS

In the modern era of infant cardiac surgery and perioperative care, children continue to demonstrate neurodevelopmental delays. The use of updated assessment tools has revealed early language dysfunction and relative sparing of motor function. Ongoing follow-up is critical in this high-risk population.

Structural connectivity relates to perinatal factors and functional impairment at 7years in children born very preterm

OBJECTIVE

To use structural connectivity to (1) compare brain networks between typically and atypically developing (very preterm) children, (2) explore associations between potential perinatal developmental disturbances and brain networks, and (3) describe associations between brain networks and functional impairments in very preterm children.

METHODS

26 full-term and 107 very preterm 7-year-old children (born <30weeks' gestational age and/or <1250g) underwent T1- and diffusion-weighted imaging. Global white matter fibre networks were produced using 80 cortical and subcortical nodes, and edges were created using constrained spherical deconvolution-based tractography. Global graph theory metrics were analysed, and regional networks were identified using network-based statistics. Cognitive and motor function were assessed at 7years of age.

RESULTS

Compared with full-term children, very preterm children had reduced density, lower global efficiency and higher local efficiency. Those with lower gestational age at birth, infection or higher neonatal brain abnormality score had reduced connectivity. Reduced connectivity within a widespread network was predictive of impaired IQ, while reduced connectivity within the right parietal and temporal lobes was associated with motor impairment in very preterm children.

CONCLUSIONS

This study utilised an innovative structural connectivity pipeline to reveal that children born very preterm have less connected and less complex brain networks compared with typically developing term-born children. Adverse perinatal factors led to disturbances in white matter connectivity, which in turn are associated with impaired functional outcomes, highlighting novel structure-function relationships.

Neurodevelopmental outcome at 2 years of age after general anaesthesia and awake-regional anaesthesia in infancy (GAS): an international multicentre, randomised controlled trial

BACKGROUND

Preclinical data suggest that general anaesthetics affect brain development. There is mixed evidence from cohort studies that young children exposed to anaesthesia can have an increased risk of poor neurodevelopmental outcome. We aimed to establish whether general anaesthesia in infancy has any effect on neurodevelopmental outcome. Here we report the secondary outcome of neurodevelopmental outcome at 2 years of age in the General Anaesthesia compared to Spinal anaesthesia (GAS) trial.

METHODS

In this international assessor-masked randomised controlled equivalence trial, we recruited infants younger than 60 weeks postmenstrual age, born at greater than 26 weeks' gestation, and who had inguinal herniorrhaphy, from 28 hospitals in Australia, Italy, the USA, the UK, Canada, the Netherlands, and New Zealand. Infants were randomly assigned (1:1) to receive either awake-regional anaesthesia or sevoflurane-based general anaesthesia. Web-based randomisation was done in blocks of two or four and stratified by site and gestational age at birth. Infants were excluded if they had existing risk factors for neurological injury. The primary outcome of the trial will be the Wechsler Preschool and Primary Scale of Intelligence Third Edition (WPPSI-III) Full Scale Intelligence Quotient score at age 5 years. The secondary outcome, reported here, is the composite cognitive score of the Bayley Scales of Infant and Toddler Development III, assessed at 2 years. The analysis was as per protocol adjusted for gestational age at birth. A difference in means of five points (1/3 SD) was predefined as the clinical equivalence margin. This trial is registered with ANZCTR, number ACTRN12606000441516 and ClinicalTrials.gov, number NCT00756600.

FINDINGS

Between Feb 9, 2007, and Jan 31, 2013, 363 infants were randomly assigned to receive awake-regional anaesthesia and 359 to general anaesthesia. Outcome data were available for 238 children in the awake-regional group and 294 in the general anaesthesia group. In the as-per-protocol analysis, the cognitive composite score (mean [SD]) was 98.6 (14.2) in the awake-regional group and 98.2 (14.7) in the general anaesthesia group. There was equivalence in mean between groups (awake-regional minus general anaesthesia 0.169, 95% CI -2.30 to 2.64). The median duration of anaesthesia in the general anaesthesia group was 54 min.

INTERPRETATION

For this secondary outcome, we found no evidence that just less than 1 h of sevoflurane anaesthesia in infancy increases the risk of adverse neurodevelopmental outcome at 2 years of age compared with awake-regional anaesthesia.

FUNDING

Australia National Health and Medical Research Council (NHMRC), Health Technologies Assessment-National Institute for Health Research UK, National Institutes of Health, Food and Drug Administration, Australian and New Zealand College of Anaesthetists, Murdoch Childrens Research Institute, Canadian Institute of Health Research, Canadian Anesthesiologists' Society, Pfizer Canada, Italian Ministry of Heath, Fonds NutsOhra, and UK Clinical Research Network (UKCRN).

High Postnatal Growth Hormone Levels Are Related to Cognitive Deficits in a Group of Children Born Very Preterm

CONTEXT AND OBJECTIVES

Little is known regarding the influence of GH on brain development, especially in infants born very preterm (VP; <30 weeks' gestation). Preterm infants are thought to have higher levels of GH in the first days of life compared with full-term infants. VP infants experience cognitive difficulties in childhood and have a diffuse pattern of structural brain abnormalities. This study aimed to explore the relationship between postnatal GH concentrations following VP birth and its association with cognitive functioning and brain volumes at age 7 years.

METHODS

Eighty-three infants born VP had GH concentrations measured at eight time points postnatally, and 2- and 6-week area under the curve (AUC) summary measures were calculated. Followup at age 7 years included neuropsychological assessment and brain magnetic resonance imaging. Univariable and multivariable regression modeling were used where AUC for GH was the main predictor of neurodevelopmental outcome at age 7 years.

RESULTS

Univariable modeling revealed that higher GH levels (2-week AUC) were related to poorer performance on a verbal working memory (P = .04) and shifting attention task (P = .01). These relationships persisted on multivariable modeling and when the 6-week AUC was analyzed; working memory (P = .03), immediate spatial memory (P = .02), and delayed spatial memory (P = .03) deficits were found. Higher GH levels were also associated with larger amygdala volumes after adjustment for potential confounders (P = .002, 2-week AUC; P = .03, 6-week AUC).

CONCLUSIONS

Higher postnatal GH levels may potentially contribute to the documented neurodevelopmental abnormalities seen in children born VP at school age.

Anesthesia and the developing brain: a way forward for clinical research

It is now well established that many general anesthetics have a variety of effects on the developing brain in animal models. In contrast, human cohort studies show mixed evidence for any association between neurobehavioural outcome and anesthesia exposure in early childhood. In spite of large volumes of research, it remains very unclear if the animal studies have any clinical relevance; or indeed how, or if, clinical practice needs to be altered. Answering these questions is of great importance given the huge numbers of young children exposed to general anesthetics. A recent meeting in Genoa brought together researchers and clinicians to map a path forward for future clinical studies. This paper describes these discussions and conclusions. It was agreed that there is a need for large, detailed, prospective, observational studies, and for carefully designed trials. It may be impossible to design or conduct a single study to completely exclude the possibility that anesthetics can, under certain circumstances, produce long-term neurobehavioural changes in humans; however , observational studies will improve our understanding of which children are at greatest risk, and may also suggest potential underlying etiologies, and clinical trials will provide the strongest evidence to test the effectiveness of different strategies or anesthetic regimens with respect to better neurobehavioral outcome.

Hormone modeling in preterm neonates: establishment of pituitary and steroid hormone reference intervals

CONTEXT

Reports suggest significant differences in serum levels of hormones in extremely preterm compared with late preterm and full-term infants.

OBJECTIVES

The purpose of this study was to develop reference intervals (RIs) for 3 pituitary hormones and 5 steroid hormones in serum of preterm infants.

DESIGN

Blood samples were collected from 248 (128 male and 120 female) preterm neonates born between 24 and 32 weeks' gestation.

SETTING

PARTICIPANTS were recruited from 3 neonatal intensive care wards in Melbourne, Australia.

PARTICIPANTS

No infant in this cohort had ambiguous genitalia or other endocrine abnormalities. All infants included in the RI determination survived beyond the equivalent of term.

INTERVENTIONS

Serum was analyzed for prolactin, FSH, and LH by automated electrochemiluminescence immunoassay (Roche Cobas 8000-e601). Liquid chromatography coupled with tandem mass spectrometry was used for analysis of 17-hydroxyprogesterone, androstenedione, cortisol, cortisone, and testosterone.

MAIN OUTCOME MEASURES

The robust method was applied to define the central 95% RI, after each hormone measure was transformed using a Box-Cox transformation to correct for asymmetry.

RESULTS

RIs were established for 8 hormones. Gender-specific intervals were developed for FSH, LH, and testosterone. Cortisone and 17- hydroxyprogesterone required division based on gestational age, with neonates born at <30 weeks' gestation demonstrating higher levels than their older counterparts. Androstenedione, cortisol, and prolactin did not require any division within this cohort for RI assignment.

CONCLUSIONS

This report provides the first characterization of serum steroids measured by mass spectrometry in preterm neonates, with the additional characterization of 3 pituitary hormones in infants born at ≤32 weeks' gestation. Use of these data allows for correct interpretation of results for very preterm neonates and reduces the risk of incorrect diagnosis due to misinterpretation of data.

Free thyroxine levels after very preterm birth and neurodevelopmental outcomes at age 7 years

BACKGROUND AND OBJECTIVES

Preterm infants commonly have transient hypothyroxinemia of prematurity after birth, which has been associated with deficits in general intellectual functioning, memory, attention, and academic achievement. However, research has predominantly focused on thyroxine levels in the first 2 weeks of life and outcomes are limited to the preschool period. Our objective was to evaluate the relationships between free thyroxine (fT₄) levels over the first 6 weeks after very preterm (VPT) birth with cognitive functioning and brain development at age 7 years.

METHODS

A total of 83 infants born VPT (<30 weeks' gestation) had fT₄ concentrations measured postnatally and 2- and 6-week area under the curve (AUC) summary measures were calculated. Follow-up at age 7 years included a neuropsychological assessment and brain MRI. Univariable and multivariable regression modeling was used where AUC for fT₄ was the main predictor of neurodevelopmental outcome at age 7 years.

RESULTS

Multivariable modeling revealed that higher, not lower, postnatal fT₄ levels (2-week AUC) were associated with poorer cognitive performances at age 7 years on tasks of verbal learning (P = .02), verbal memory (P = .03), and simple reaction time (P < .001). A similar pattern of results was found when the 6-week AUC was examined. No significant associations between postnatal fT₄ levels and brain volumes at age 7 years were identified.

CONCLUSIONS

Results are contradictory to previous observations and suggest that after adjustment for confounders, higher postnatal fT₄ levels in VPT infants, rather than lower levels, may be a marker of adverse neuropsychological development in childhood.

Alterations in the optic radiations of very preterm children-Perinatal predictors and relationships with visual outcomes

Children born very preterm (VPT) are at risk for visual impairments, the main risk factors being retinopathy of prematurity and cerebral white matter injury, however these only partially account for visual impairments in VPT children. This study aimed to compare optic radiation microstructure and volume between VPT and term-born children, and to investigate associations between 1) perinatal variables and optic radiations; 2) optic radiations and visual function in VPT children. We hypothesized that optic radiation microstructure would be altered in VPT children, predicted by neonatal cerebral white matter abnormality and retinopathy of prematurity, and associated with visual impairments.

142 VPT children and 32 controls underwent diffusion-weighted magnetic resonance imaging at 7 years of age. Optic radiations were delineated using constrained spherical deconvolution tractography. Tract volume and average diffusion tensor values for the whole optic radiations and three sub-regions were compared between the VPT and control groups, and correlated with perinatal variables and 7-year visual outcome data.

Total tract volumes and average diffusion values were similar between VPT and control groups. On regional analysis of the optic radiation, mean and radial diffusivity were higher within the middle sub-regions in VPT compared with control children. Neonatal white matter abnormalities and retinopathy of prematurity were associated with optic radiation diffusion values. Lower fractional anisotropy in the anterior sub-regions was associated with poor visual acuity and increased likelihood of other visual defects.

This study presents evidence for microstructural alterations in the optic radiations of VPT children, which are largely predicted by white matter abnormality or severe retinopathy of prematurity, and may partially explain the higher rate of visual impairments in VPT children.

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This study compares optic radiations between very preterm and control 7-year-olds.

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There are microstructural alterations in the optic radiations of VPT children.

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The main risk factors are retinopathy of prematurity and white matter injury.

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Microstructural alterations associate with poor visual acuity and visual defects.

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This study elucidates neuroanatomical correlates of visual impairment in prematurity.

New White Matter Brain Injury After Infant Heart Surgery Is Associated With Diagnostic Group and the Use of Circulatory Arrest

Background—

Abnormalities on magnetic resonance imaging scans are common both before and after surgery for congenital heart disease in early infancy. The aim of this study was to prospectively investigate the nature, timing, and consequences of brain injury on magnetic resonance imaging in a cohort of young infants undergoing surgery for congenital heart disease both with and without cardiopulmonary bypass.

Methods and Results—

A total of 153 infants undergoing surgery for congenital heart disease at <8 weeks of age underwent serial magnetic resonance imaging scans before and after surgery and at 3 months of age, as well as neurodevelopmental assessment at 2 years of age. White matter injury (WMI) was the commonest type of injury both before and after surgery. It occurred in 20% of infants before surgery and was associated with a less mature brain. New WMI after surgery was present in 44% of infants and at similar rates after surgery with or without cardiopulmonary bypass. The most important association was diagnostic group ( P <0.001). In infants having arch reconstruction, the use and duration of circulatory arrest were significantly associated with new WMI. New WMI was also associated with the duration of cardiopulmonary bypass, postoperative lactate level, brain maturity, and WMI before surgery. Brain immaturity but not brain injury was associated with impaired neurodevelopment at 2 years of age.

Conclusions—

New WMI is common after surgery for congenital heart disease and occurs at the same rate in infants undergoing surgery with and without cardiopulmonary bypass. New WMI is associated with diagnostic group and, in infants undergoing arch surgery, the use of circulatory arrest.

Amplitude-integrated electroencephalography and brain injury in infants undergoing Norwood-type operations

BACKGROUND

Perioperative brain injury is common in infants undergoing cardiac surgery. Amplitude-integrated electroencephalography (aEEG) provides real-time neurologic monitoring and can identify seizures and abnormalities of background cerebral activity. We aimed to determine the incidence of perioperative electrical seizures, and to establish the background pattern of aEEG, in neonates undergoing Norwood-type palliations for complex congenital heart disease in relation to outcome at 2 years.

METHODS

Thirty-nine full-term neonates undergoing Norwood-type operations underwent aEEG monitoring before and during surgery and for 72 hours postoperatively. The perfusion strategy included full-flow moderately hypothermic cardiopulmonary bypass with antegrade cerebral perfusion. Amplitude-integrated electroencephalography tracings were reviewed for seizure activity and background pattern. Survivors underwent neurodevelopmental outcome assessment using the Bayley Scales of Infant Development (3rd edition) at 2 years of age.

RESULTS

Thirteen (33%) infants had electrical seizures, including 9 with intraoperative seizures and 7 with postoperative seizures. Seizures were associated with significantly increased mortality, but not with neurodevelopmental impairment in survivors. Delay in recovery of the aEEG background beyond 48 hours was also associated with increased mortality and worse motor development.

CONCLUSIONS

Perioperative seizures were common in this cohort. Intraoperative seizures predominantly affected the left hemisphere during antegrade cerebral perfusion. Delayed recovery in aEEG background was associated with increased risk of early mortality and worse motor development. Ongoing monitoring is essential to determine the longer-term significance of these findings.

Hypoxic ischemic encephalopathy--what can we learn from humans?

Hypoxic ischemic encephalopathy (HIE) is a condition that occurs in both human newborns and foals. The condition is the subject of extensive current research in human infants, but there have been no direct studies of HIE in foals, and hence, knowledge of the condition has been extrapolated from studies in humans and other animal models. The purpose of this review article is to highlight the most up-to-date and relevant research in the human field, and discuss how this potentially might have an impact in the management of foals with HIE.

Factor Analysis of the Interpersonal Trust Scale with a Noncollege Population

This study tested the invariance of the factorial structure of Rotter's Interpersonal Trust Scale (ITS) in a noncollege population. Exploratory factor analysis of the responses of 214 volunteers yielded three factors interpreted as Exploitation, Sincerity, and Institutional Trust. This factor solution was cross-validated in a confirmation sample of 196 volunteers. Cosines between corresponding factors were high across samples and across sex. The similarity was pointed out between the present factor structure and the results of earlier studies with college students. Implications for possible refinement of the ITS were discussed.

Psychological responses to cancer: a case for cancer support groups

This study investigates the responses of patients and their carers to the diagnosis of cancer. The reporting of stress by patients, using linear analogue scales, and their psychological distress, as measured by the General Health Questionnaire, indicated benefits for members of a community-based cancer support group. The responses of carers revealed that the impact of the diagnosis was as great on them as on patients. Various mediators were considered and age was found to significantly influence the reporting of stress. The limitations and implications of the findings are discussed.

Abnormal white matter signal on MR imaging is related to abnormal tissue microstructure

BACKGROUND AND PURPOSE

White matter signal-intensity abnormalities (WMSA) on MR imaging are related to adverse neurodevelopmental outcome in extremely preterm infants. Diffusion tensor imaging (DTI) may detect alterations in cerebral white matter microstructure and thus may help confirm the pathologic basis of WMSA. This study aimed to relate regional DTI measures with severity of WMSA in very preterm infants.

MATERIALS AND METHODS

One hundred eleven preterm infants (birth weight, <1250 g and/or gestational age, <30 weeks) were scanned at term-equivalent age (1.5T). WMSA were classified as normal, focal, or extensive. Apparent diffusion coefficient (ADC), fractional anisotropy (FA), axial (lambda1), and radial ([lambda2 + lambda3]/2) diffusivity were calculated in 12 regions of interest placed in the bilateral posterior limbs of the internal capsule, frontal (superior and inferior), sensorimotor, and occipital (superior and inferior) white matter regions. Data were compared by using 1-way analysis of variance, with a Bonferroni correction for multiple comparisons.

RESULTS

Thirty-nine infants had normal, 59 infants had focal, and 13 infants had extensive WMSA. Compared with infants with normal or focal WMSA, infants with extensive WMSA had significantly lower FA in the internal capsule (P < .001), right inferior frontal regions (P < .05), and right superior occipital regions (P = .01); and higher radial diffusivity in the right internal capsule (P = .005), bilateral sensorimotor (P < .05), and right superior occipital regions (P < .05). Compared with infants with normal WMSA, infants with extensive WMSA had significantly higher ADC in bilateral sensorimotor regions (P < .01) and right superior occipital regions (P = .01), and lower axial diffusivity in the bilateral sensorimotor regions (P < .05).

CONCLUSIONS

There are significant region-specific changes in ADC, FA, radial diffusivity, and axial diffusivity in preterm infants with extensive WMSA. Altered radial diffusivity was most prominent. This implies that disrupted premyelinating oligodendroglia is the major correlate with extensive WMSA rather than axonal pathology.

Transient anomalies in genital appearance in some extremely preterm female infants may be the result of foetal programming causing a surge in LH and the over activation of the pituitary-gonadal axis

AIM

Animal studies have linked foetal programming with the development of the polycystic ovarian syndrome, and metabolic syndrome, in adulthood. The objective is to describe the investigation of four extreme-premature female infants born between 25 and 29 weeks' gestation with apparent genital abnormalities in association with unusually high androgens and gonadotrophins, to postulate a cause and to raise awareness of pitfalls in assessment of these infants.

METHODS

Clinical examination and biochemical evaluation of four infants referred for apparent congenital ambiguity.

RESULTS

Female gender was assigned at birth. Chromosome analysis confirmed 46XX, urine steroid profiles demonstrated no evidence of congenital adrenal hyperplasia and only the expected levels of foetal adrenal steroids. Elevated LH (up to 162 IU/l), testosterone (up to 2.6 nmol/l), Delta(4 )androstenedione (up to > 35 nmol/l) and dehydro-epiandrosterone sulphate (DHEAS) (up to 26.6 micromol/l) were seen in all four infants. These decreased over time but were significantly different from a control population of premature infants of similar gestational age.

CONCLUSIONS

We postulate that the clinical pattern of apparent clitoral enlargement in some extremely premature infants may reflect true temporary virilization due to an unusually high (or excessive) LH surge, in turn causing high foetal androgens. Foetal programming of gonadotrophin excess is probably the primary cause of androgen increase, in turn causing virilization, in some extreme-premature infants. These may potentially be a group at future risk of polycystic ovary or metabolic syndrome, however, further work needs to be conducted to substantiate this hypothesis.

A novel quantitative simple brain metric using MR imaging for preterm infants

BACKGROUND AND PURPOSE

The application of volumetric techniques to preterm infants has revealed brain volume reductions. Such quantitative data are not available in routine neonatal radiologic care. The objective of this study was to develop simple brain metrics to compare brain size in preterm and term infants and to correlate these metrics with brain volumes from volumetric MR imaging techniques.

MATERIALS AND METHODS

MR images from 189 preterm infants <30 weeks' gestational age or <1250 g birthweight scanned at term-equivalent age and 36 term infants were studied. Fifteen tissue and fluid measures were systematically evaluated on 4 selected sections. The results were correlated with total brain, gray matter, white matter, and CSF volumes.

RESULTS

The mean bifrontal, biparietal, and transverse cerebellar diameters were reduced (-11.6%, 95% confidence interval [CI], -13.8% to -9.3%; -12%, 95% CI, -14% to -9.8%; and -8.7%, 95% CI, -10.5% to -7% respectively) and the mean left ventricle diameter was increased (+22.3%, 95% CI, 2.9%-41.6%) in preterm infants (P < .01). Strong correlations were found between the bifrontal and biparietal measures with total brain tissue volume, whereas the size of the ventricles and the interhemispheric measure correlated with CSF volume. Intraobserver reliability was high (intraclass correlation coefficients [ICC], >0.7), where interobserver agreement was acceptable for tissue measures (ICC, >0.6) but lower for fluid measures (ICC, <0.4).

CONCLUSIONS

Simple brain metrics at term-equivalent age showed smaller brain diameters and increased ventricle size in preterm infants compared with full-term infants. These measures represent a reliable and easily applicable method to quantify brain growth and assess brain atrophy in this at-risk population.

I.V. acetaminophen pharmacokinetics in neonates after multiple doses

BACKGROUND

Pharmacokinetics of an i.v. prodrug of acetaminophen (propacetamol) in neonates after repeat dosing are reported, with scant data for i.v. acetaminophen formulation.

METHODS

Neonates from an intensive care unit received 6-hourly prn i.v. acetaminophen dosed according to postmenstrual age (PMA): 28-32 weeks, 10 mg kg(-1); 32-36 weeks, 12.5 mg kg(-1); and > or =36 weeks, 15 mg kg(-1). A maximum of five blood samples for assay and liver function tests (LFTs) were collected. A one-compartment linear disposition model (zero-order input; first-order elimination) was used to describe time-concentration profiles using population modelling (NONMEM).

RESULTS

Fifty neonates, median (range) PMA 38.6 (32-45) weeks, mean (SD) weight 2.9 (0.7) kg, received a mean of 15 doses over a median 4 days with 189 serum acetaminophen and 231 LFT measurements. Standardized population parameter estimates for a term neonate were clearance (CL) 5.24 (CV 30.5%) litre h(-1) 70 kg(-1) and volume of distribution (V) 76 (29.6%) litre 70 kg(-1). CL increased with PMA from 4.4 litre h(-1) 70 kg(-1) at 34 weeks to 6.3 litre h(-1) 70 kg(-1) at 46 weeks. The presence of unconjugated hyperbilirubinaemia was associated with reduced CL: 150 micromol litre(-1) associated with 40% CL reduction. Acetaminophen concentrations between 10 and 23 mg litre(-1) at steady state are predicted after 15 mg kg(-1) 6-hourly for a neonate of PMA 40 weeks. Hepatic enzyme analysis of daily samples changed significantly for one patient whose alanine aminotransferase concentration tripled.

CONCLUSIONS

The parameter estimates are similar to those described for propacetamol. There was no evidence of hepatotoxicity. Unconjugated hyperbilirubinaemia impacts upon CL, dictating dose reduction.

Single versus bihemispheric amplitude-integrated electroencephalography in relation to cerebral injury and outcome in the term encephalopathic infant

BACKGROUND

The demand for early diagnosis and prognostication of cerebral injury in the encephalopathic term infant is increasing to facilitate appropriate management. The single-channel amplitude-integrated electroencephalogram (S-aEEG) has been shown to have predictive utility for the severely encephalopathic infant. New bedside aEEG devices with more channels are entering the neonatal environment. Little data are available to compare the utility of two channels (B-aEEG) with that of an S-aEEG recording.

AIM

To compare the utility of the S-aEEG and the B-aEEG in the prediction of cerebral injury, as determined by magnetic resonance imaging (MRI), and neurodevelopmental outcome in the term encephalopathic infant.

METHODS

Term encephalopathic infants, with or without seizures, admitted to a level III NICU were included in this study. These infants had simultaneous S-aEEG and B-aEEG recordings. MRI was undertaken during the clinical course and classified as to the extent of cerebral injury. Neurological outcome was assessed at 2 years of age.

RESULTS

Twenty-eight encephalopathic term infants were included in the study. There was high level of agreement between both brain monitors (Kappa = 0.68, P < 0.001), but there was disagreement in the classification in four cases where the S-aEEG was normal when the B-aEEG was severely abnormal (McNemar's test P = 0.046). Of note in these four cases, all had a severely abnormal MRI and poor neurodevelopmental outcome at 2 years.

CONCLUSION

Amplitude measurements by the B-aEEG appear more sensitive in detecting cerebral injury in comparison with the S-aEEG, particularly in the setting of unilateral injury.

Luteinizing hormone and follicle-stimulating hormone levels in extreme prematurity: development of reference intervals

OBJECTIVES

Establishing pediatric reference intervals has always been challenging, with most ranges used in pediatric laboratories developed over many years. The clinical interpretation of gonadotropins is important in the context of ambiguous genitalia. The aim of this study was to develop reference intervals for luteinizing hormone and follicle-stimulating hormone in infants born between 24 and 29 weeks' gestation.

METHODS

Samples were collected at 0 to 43 days after birth from 82 premature infants born <30 weeks' gestation for analysis of luteinizing hormone and follicle-stimulating hormone by automated immunochemiluminometric immunoassays.

RESULTS

The 43 male infants demonstrated a range of luteinizing hormone levels from 0.1 to 13.4 IU/L and of follicle-stimulating hormone levels from 0.3 to 4.6 IU/L. The 39 female infants demonstrated a range of luteinizing hormone levels from 0.2 to 54.4 IU/L and of follicle-stimulating hormone levels from 1.2 to 167.0 IU/L. The ratio of luteinizing hormone/follicle-stimulating hormone levels differed with males, ranging from 0.3 to 9.4, and females, at <0.5.

CONCLUSION

These data provide guidance for the interpretation of luteinizing hormone and follicle-stimulating hormone levels for the first 6 weeks of life in extremely premature infants born between 24 and 29 weeks' gestation. The availability of age-appropriate reference intervals is essential for correct and timely interpretation of biochemical results to the clinician.

Monitoring the neonatal brain: a survey of current practice among Australian and New Zealand neonatologists

AIMS

There is considerable variation in the use of brain imaging and electrophysiological monitoring of encephalopathic term infants. The aims of this study were (i) to document the current practice among Australian and New Zealand neonatologists; and (ii) to identify the factors that influence local practice.

METHODS

A postal questionnaire was sent to all 152 neonatologists in Australia and New Zealand. A hypothetical scenario of an encephalopathic term infant was presented and clinicians were asked a series of questions relating to their use of magnetic resonance imaging (MRI), computed tomography, ultrasound, electroencephalography and amplitude integrated electroencephalography.

RESULTS

There was a 62% response rate. Twenty-two per cent of respondents would not routinely perform an MRI brain scan in the given scenario. Limited availability, expense, logistics of transport and a lack of confidence in the ability of MRI to provide additional clinical information appear to be the main factors affecting practice. When a scan is performed, the majority of respondents (72%) perform the scan on day 5 or later. Twenty-three per cent of respondents experience significant delays when they request an MRI scan. Regarding electrophysiological monitoring, amplitude integrated electroencephalography would be used by 62% of respondents in the given scenario.

CONCLUSIONS

This study demonstrates that MRI is now widely used by neonatologists in Australia and New Zealand. However, local resource limitations and a lack of confidence in the utility of MRI continue to limit its use.

Postnatal thyroid hormones for respiratory distress syndrome in preterm infants

BACKGROUND

Preterm infants with respiratory distress syndrome are at increased risk of adverse neonatal and developmental outcomes. In animal research, thyroid hormones stimulate surfactant production and reduce the incidence and severity of respiratory distress when given antenatally.

OBJECTIVES

To determine whether thyroid hormone therapy used postnatally in preterm infants with suspected respiratory distress syndrome results in clinically important improvements in respiratory morbidity and subsequent improvements in neonatal and long term outcomes.

SEARCH STRATEGY

Searches were performed of The Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, Issue 1, 2006), MEDLINE (1966 - March 2006), PREMEDLINE (March 2006), EMBASE (1980 - March 2006), previous reviews including cross references, abstracts and conference proceedings, supplemented by requests to expert informants.

SELECTION CRITERIA

Trials that enrolled preterm infants with suspected respiratory distress syndrome and allocated infants thyroid hormone treatment compared to control commenced in the first 48 hours after birth.

DATA COLLECTION AND ANALYSIS

Independent assessment of trial quality and data extraction by each author. Synthesis of data using relative risk (RR) and weighted mean difference (WMD) using standard methods of the Cochrane Collaboration and its Neonatal Review Group.

MAIN RESULTS

Two studies enrolled preterm infants with respiratory distress. Amato (1988) allocated infants to L-thyroxine 50 mug/dose at 1 and at 24 hours or no treatment. Amato (1989) allocated infants to L-triiodothyronine 50 mug/day in two divided doses for two days or no treatment. Both studies had methodological concerns including quasi-random methods of patient allocation, no blinding of treatment or measurement and substantial post allocation losses. Neither study reported any significant benefits in neonatal morbidity or mortality from use of thyroid hormones. Meta-analysis of two studies (80 infants) found no significant difference in mortality to discharge (typical RR 1.00, 95% CI 0.47, 2.14). Amato 1988 reported no significant difference in use of mechanical ventilation (RR 0.64, 95% CI 0.38, 1.09). No significant effects were found in use of mechanical ventilation, duration of mechanical ventilation, air leak, CLD at 28 days in survivors, patent ductus arteriosus, intraventricular haemorrhage or necrotising enterocolitis. Neurodevelopment was not reported.

AUTHORS' CONCLUSIONS

There is no evidence from controlled clinical trials that postnatal thyroid hormone treatment reduces the severity of respiratory distress syndrome, neonatal morbidity or mortality in preterm infants with respiratory distress syndrome.

Prophylactic postnatal thyroid hormones for prevention of morbidity and mortality in preterm infants

BACKGROUND

Observational studies have shown an association between transiently low thyroid hormone levels in preterm infants in the first weeks of life (transient hypothyroxinaemia) and abnormal neurodevelopmental outcome. Thyroid hormone replacement might prevent this.

OBJECTIVES

To determine whether prophylactic thyroid hormones given to preterm infants without congenital hypothyroidism result in clinically important changes in neonatal and long term outcomes.

SEARCH STRATEGY

The standard search strategy of the Neonatal Review Group was used. This included searches of the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, Issue 1, 2006), MEDLINE (1966 - March 2006), EMBASE, PREMEDLINE, and searches of abstracts of conference proceedings, citations of published articles and expert informants.

SELECTION CRITERIA

All trials using random or quasi-random patient allocation in which prophylactic thyroid hormone treatment was compared to control in premature infants.

DATA COLLECTION AND ANALYSIS

Assessment of trial quality, data extraction and synthesis of data, using relative risk (RR) and weighted mean difference (WMD), were performed using standard methods of the Cochrane Collaboration and its Neonatal Review Group.

MAIN RESULTS

Four studies enrolling 318 infants were included. All studies enrolled preterm infants on the basis of gestational age criteria. All studies commenced treatment in the first 48 hours, but used different regimens, dose and durations of treatment. All four studies used thyroxine (T4). Valerio 2004 incorporated one arm with an early short course of T3, then T4 for 6 weeks. Only two studies with neurodevelopmental follow-up were of good methodology (van Wassenaer 1997; Vanhole 1997). All studies were small with the largest (van Wassenaer 1997) enrolling 200 infants.No significant difference was found in neonatal morbidity, mortality or neurodevelopmental outcome in infants who received thyroid hormones compared to control. van Wassenaer 1997 reported no significant difference in abnormal mental development at 6, 12, 24 months (RR 0.67, 95% CI 0.28, 1.56) or five years (RR 0.66, 95% CI 0.22, 1.99) or cerebral palsy assessed at five years (RR 0.72, 95% CI 0.28, 1.84). Meta-analysis of two studies (van Wassenaer 1997, Vanhole 1997) found no significant difference in the Bayley MDI (WMD -1.14, 95% CI -5.46, 3.19) and PDI (WMD 0.22, 95% CI -4.80, 5.24) at 7 - 12 months. van Wassenaer 1997 reported no significant difference in the Bayley MDI (MD -3.50, 95% CI -11.21, 4.21) and PDI (MD 3.10, 95% CI -3.31, 9.51) at 24 months, IQ scores at 5 years (MD -2.10, 95% CI -7.91, 3.71) and children in special schooling at 10 years (RR 0.88, 95% CI 0.43, 1.83). Meta-analysis of all four trials found no significant difference in mortality to discharge (typical RR 0.76, 95% CI 0.46 to 1.24). van Wassenaer 1997 reported no significant difference in death or cerebral palsy at five years (RR 0.70, 95% CI 0.43 to 1.14). No significant differences were reported for neonatal morbidities, including the need for mechanical ventilation, duration of mechanical ventilation, air leak, CLD in survivors at 28 days or 36 weeks, intraventricular haemorrhage, severe intraventricular haemorrhage, periventricular leucomalacia, patent ductus arteriosus, sepsis, necrotising enterocolitis or retinopathy of prematurity.

AUTHORS' CONCLUSIONS

This review does not support the use of prophylactic thyroid hormones in preterm infants to reduce neonatal mortality, neonatal morbidity or improve neurodevelopmental outcomes. An adequately powered clinical trial of thyroid hormone supplementation with the goal of preventing the postnatal nadir of thyroid hormone levels seen in very preterm infants is required.

Postnatal thyroid hormones for preterm infants with transient hypothyroxinaemia

BACKGROUND

Extremely premature infants are at risk of transient hypothyroxinaemia in the first weeks after birth. These low thyroid hormone levels are associated with an increased incidence of neonatal morbidity, mortality and longer term developmental impairments. Thyroid hormone therapy might prevent these problems.

OBJECTIVES

To determine the evidence for thyroid hormone therapy in preterm infants with transient hypothyroxinaemia (low thyroid hormone level, normal TSH) for improvement of neonatal outcomes and neurodevelopment.

SEARCH STRATEGY

Searches were performed of The Cochrane Central Register of Controlled (CENTRAL, The Cochrane Library, Issue 1, 2006), MEDLINE (1966 - March 2006), PREMEDLINE (March 2006), EMBASE (1980 - March 2006), previous reviews including cross references, abstracts and conference proceedings, supplemented by requests to expert informants.

SELECTION CRITERIA

Trials enrolling preterm infants with transient hypothyroxinaemia (low thyroid hormone level, normal TSH level) in the neonatal period, using random or quasi-random patient allocation to thyroid hormone therapy compared to control (placebo or no treatment).

DATA COLLECTION AND ANALYSIS

Independent assessment of trial quality and data extraction by each review author. Synthesis of data using relative risk (RR) and weighted mean difference (WMD) using standard methods of the Cochrane Collaboration and its Neonatal Review Group.

MAIN RESULTS

Only one study was eligible. Chowdhry (1984) enrolled 23 infants < 1250 g and 25 - 28 weeks gestation with transient hypothyroxinaemia (serum total T4 </=4 mug/dl and TSH </= 20 IU/L). Infants were randomised to thyroxine 10 mug/kg/day or placebo beginning on day 15 and continuing daily for seven weeks. Chowdhry (1984) reported no neonatal mortality and one infant death in each group prior to discharge. No significant difference was reported in CLD at 28 days or 36 weeks, patent ductus arteriosus, necrotising enterocolitis, retinopathy or prematurity, weight gain, growth in head circumference or length. No significant difference was reported for mean T4 levels between thyroxine and placebo treated infants on day 21, 35, 49, 63 and 77 after birth. Free T4 was not measured. Neurodevelopmental follow up was inadequate to draw any conclusions from.

AUTHORS' CONCLUSIONS

There is insufficient evidence to determine whether use of thyroid hormones for treatment of preterm infants with transient hypothyroxinaemia results in changes in neonatal morbidity and mortality, or reductions in neurodevelopmental impairments. Further research is required.

Assessment of the impact of the removal of cerebrospinal fluid on cerebral tissue volumes by advanced volumetric 3D-MRI in posthaemorrhagic hydrocephalus in a premature infant

Current clinical practice in the premature infant with posthaemorrhagic ventricular dilatation (PHVD) includes drainage of cerebrospinal fluid (CSF). This case study used advanced volumetric three dimensional magnetic resonance imaging to document the impact of CSF removal on the volume of regional brain tissues in a premature infant with PHVD. The removal of a large volume of CSF was associated with an identical reduction in CSF volume, but more dramatically with a significant increase in the regional volumes of cortical grey matter and myelinated white matter. The alterations in cerebral cortical grey matter and myelinated white matter volumes may provide insight into the established association of PHVD with deficits in cognitive and motor functions.

Where patients with cancer die in South Australia, 1990-1999: a population-based review

OBJECTIVE

To determine the place of death of South Australians who die of cancer.

DESIGN

A population-based, cross-sectional study of data from the South Australian Cancer Registry.

PARTICIPANTS

29,230 patients with cancer dying in 1990-1999.

MAIN OUTCOME MEASURES

Place of death; patient demography; year of death; survival from diagnosis; and type of cancer.

RESULTS

25.0% of patients died in a metropolitan public hospital, 19.9% in a hospice, 16.9% in a country hospital, 15.8% at a private residence, 12.7% in a metropolitan private hospital, and 9.7% in a nursing home. Although the change in place of death was not marked, multivariate logistic regression showed a secular trend away from metropolitan public hospitals towards metropolitan private hospitals and, in 1998-1999, towards nursing homes. Patients dying of cancer in a metropolitan public hospital were more likely to be younger, males, born outside Australia, and residents of lower socioeconomic areas of Adelaide. They were also more likely to have died within three months of diagnosis, and to have a haematological malignancy or a cancer of the upper digestive tract, lung or female breast. In contrast, patients dying at a private residence tended to be under 70 years and comprise longer-term survivors. Country residents were less likely than Adelaide residents to die in a hospice.

CONCLUSION

The proportion of patients dying in different settings have health service implications. The relatively low use of hospice facilities by country patients may reflect differences in access to hospice facilities.

Pre-eclampsia: a predisposing factor for neonatal venous sinus thrombosis?

Neonatal venous sinus thrombosis is a well-recognized, but infrequently diagnosed, cause of neonatal encephalopathy. Previous reports have tended to omit reference to the importance of maternal factors in predisposing the infant to this condition. This report, in which eight patients with neonatal venous sinus thrombosis are presented, will reveal a strong association between pre-eclampsia, prothrombotic disorders, and neonatal venous sinus thrombosis. Contrary to previously published reports, there is a high likelihood of neurodevelopmental residua after this condition.

Model-based inversion of speckle interferometer fringe patterns

Micrometer-scale rigid-body translations are determined fromelectronic speckle interferometric fringe patterns. An iterativeminimum error procedure employs the relative fringe order of pickedpositions of fringe maxima and minima within a single interferogram tocalculate the displacement field directly. The method does notcalculate the displacement at a single point but relies on theassumption that the character, but not the magnitudes or directions, ofthe displacements over the viewing area of the interferogram isknown. That is, a model of the displacements exists. Onperfect, noise-free forward modeled fringe patterns calculated for an 8.0-mum displacement, the phase error is less than 2 x10(-6) fringe orders (1.3 x 10(-5) rad)and probably results only from numerical noise in the inversion. Onreal fringe patterns obtained in electronic speckle interferometricexperiments, mean phase errors are generally less than 5 x10(-5) fringe orders (3.2 x 10(-4)rad), suggesting that the technique is robust despite errorsresulting from speckle noise, lack of accuracy in positioning ofexperimental components, and image-distortion corrections.

Optimization of fringe pattern calculation with direct correlations in speckle interferometry

A direct correlation technique is used to calculate correlation fringe patterns from consecutive speckle patterns acquired with a dual-beam electronic speckle interferometer. Although more calculations are required than in standard image differencing routines, an advantage of the method is that the illumination over the surface of the object need not be uniform. In the method, Pearson's coefficient of correlation between the intensities within a set of adjacent pixels is calculated. This has the added advantage of being directly related to the theoretical phase-dependent correlation. A mapping of this measure of correlation results in the correlation fringe pattern. Laboratory tests were carried out with in-plane translations ranging from 5 to 45 mum. The correlation calculations were carried out by using cells (square sets of pixels) in the raw speckle images with dimensions ranging from 2 pixels x 2 pixels to 19 pixels x 19 pixels. Both cell dimension and translation magnitude dependent decorrelation effects influence the quality of the correlation fringe patterns.