Therapeutic hypothermia following perinatal asphyxia

Acupuncture for hypoxic ischemic encephalopathy in neonates

BACKGROUND

Peripartum asphyxia affects three to five per 1000 live births, with moderate or severe hypoxic ischemic encephalopathy (HIE) occurring in 0.5 to 1 per 1000 live births, and is associated with high mortality and morbidity. Therapeutic hypothermia is an effective treatment, but alternative therapies such as acupuncture are also used.

OBJECTIVES

To determine the benefits and harms of acupuncture (e.g. needle acupuncture with or without electrical stimulation; laser acupuncture; non-penetrating types of manual or embedded acupressure) on mortality and morbidity in neonates with HIE, compared with 1) no treatment, 2) placebo or sham treatment, 3) any pharmacologic treatment, or 4) different types of acupuncture.

SEARCH METHODS

We searched CENTRAL, PubMed, Embase, ClinicalTrials.gov, and the WHO ICTRP in March 2023. We conducted a search of the grey literature to identify reports of trials conducted by or referenced in research by CORDIS EU, National Institute for Health and Care Excellence (NICE), and NHSGGC Paediatrics for Health Professionals. We also checked the reference lists of relevant articles to identify additional studies.

SELECTION CRITERIA

We included randomized controlled trials (RCTs) or quasi-RCTs and cluster-randomized trials. We included studies where participants were term infants (37 weeks or greater) and late preterm infants (34 + 0 to 36 + 6 weeks' gestation) 10 days of age or less, with evidence of peripartum asphyxia. We included studies on acupuncture (e.g. needle acupuncture with or without electrical stimulation; laser acupuncture; non-penetrating types of manual or embedded acupressure). We included studies where acupuncture was compared with: 1) no treatment; 2) placebo or sham treatment; 3) any pharmacologic treatment; or 4) different types of acupuncture.

DATA COLLECTION AND ANALYSIS

We used standard Cochrane methods. Our primary outcomes were all-cause mortality at the latest follow-up, major neurodevelopmental disability in children aged 18 to 24 months and aged 3 to 5 years, adverse events until hospital discharge, and length of hospital stay.

MAIN RESULTS

We included four studies (enrolling 464 infants) that compared acupuncture with no treatment. The studies ranged in size from 60 to 200 infants. Three studies were conducted in China and one in Russia. None of the four studies reported on any of the prespecified outcomes of our review. We did not identify any ongoing studies.

AUTHORS' CONCLUSIONS

There is limited availability of studies addressing this specific population. The included studies did not assess mortality, long-term neurodevelopmental outcomes, or adverse effects of acupuncture. We are unable to draw any conclusions about the benefits and harms of acupuncture for HIE in neonates. In light of the current limitations, clinicians are urged to approach the use of acupuncture in neonates with HIE cautiously, as there is no evidence to support its routine application. The available trials assessed surrogate outcomes that have a relatively small impact on newborns, and failed to report important outcomes such as mortality and long-term neurodevelopmental outcomes. Other available trials were performed on older infants who had experienced neonatal HIE. Given the lack of available evidence, well-designed randomized controlled trials with relevant outcomes such as mortality and neurodevelopmental outcomes are essential to evaluate the efficacy and safety of acupuncture for HIE in neonates.

Declining incidence of cerebral palsy in South Korea

Presuming that the incidence of cerebral palsy (CP) in Korea is decreasing due to medical advances, we analyzed the trends and risk factors of CP in changing circumstances. We identified all women who delivered a singleton between 2007 and 2015 using the Korea National Health Insurance (KNHI). Information on pregnancy and birth was obtained by linking the KNHI claims database and data from the national health-screening program for infants and children. The 4-years incidence of CP decreased significantly from 4.77 to 2.52 per 1000 babies during the study period. The multivariate analysis revealed that the risk of developing CP was 29.5 times higher in preterm infants born before 28 weeks of gestational age, 24.5 times higher in infants born between 28 and 34 weeks, and 4.5 times higher in infants born between 34 and 36 weeks, compared to full-term appropriate for age (2.5 ~ 4 kg of body weight) infants. 5.6 times higher in those with birth weight < 2500 g, and 3.8 times higher in pregnancies with polyhydramnios. Additionally, respiratory distress syndrome increased the risk of developing CP by 2.04 times, while necrotizing enterocolitis was associated with a 2.80-fold increased risk of CP. In Korea, the incidence of CP in singleton decreased from 2007 to 2015. We need to continue to focus on developing medical technologies for the early detection of high-risk neonates and minimizing brain damage to reduce the incidence rate of CP effectively.

Cerebral Palsy-Trends in Epidemiology and Recent Development in Prenatal Mechanisms of Disease, Treatment, and Prevention

Cerebral palsy (CP) is the most common motor disability in childhood. This syndrome is the manifestation of intrauterine pathologies, intrapartum complications, and the postnatal sequel, especially among preterm neonates. A double hit model theory is proposed suggesting that an intrauterine condition along with intrapartum or postnatal insult lead to the development of CP. Recent reports demonstrated that treatment during the process of preterm birth such as magnesium sulfate and postnatal modalities such as cooling may prevent or reduce the prevalence of this syndrome. Moreover, animal models demonstrated that postnatal treatment with anti-inflammatory drugs coupled with nanoparticles may affect the course of the disease in pups with neuroinflammation. This review will describe the changes in the epidemiology of this disease, the underlying prenatal mechanisms, and possible treatments that may reduce the prevalence of CP and alter the course of the disease.

Intravenous nanosomes of quercetin improve brain function and hemodynamic instability after severe hypoxia in newborn piglets

Perinatal asphyxia is a major cause of death and neurological morbidity in newborns and oxidative stress is one of the critical mechanisms leading to permanent brain lesions in this pathology. In this context we have chosen quercetin, a natural antioxidant, known also by its brain protective effects to study its potential as a therapy for brain pathology provoked by severe hypoxia in the brain. To overcame the difficulties of quercetin to access the brain, we have developed lecithin/cholesterol/cyclodextrin nanosomes as a safe and protective vehicle. We have applied the nanosomal preparation intravenously to newborn piglets submitted to a severe hypoxic or ischemic/hypoxic episode and followed them for 8 or 72 h, respectively. Either towards the end of 8 h after hypoxia or up to 72 h after, electroencephalographic amplitude records in animals that received the nanosomes improved significantly. Animals receiving quercetin also stabilized blood pressure and recovered spontaneous breathing. In this experimental group mechanical ventilation assistance was withdrawn in the first 24 h while the hypoxic and vehicle groups required more than 24 h of mechanical ventilation. Three days after the hypoxia the suckling and walking capacity in the group that received quercetin recovered significantly compared with the hypoxic groups. Pathological studies did not show significant differences in the brain of newborn piglets treated with nanosomes compared with hypoxic groups. The beneficial effects of quercetin nanosomal preparation after experimental perinatal asphyxia show it as a promising putative treatment for the damaged brain in development.

Mechanisms of hypothermia-induced cell protection in the brain

Therapeutic hypothermia is an effective cytoprotectant and promising intervention shown to improve outcome in patients following cardiac arrest and neonatal hypoxia-ischemia. However, despite our clinical and experimental experiences, the protective molecular mechanisms of therapeutic hypothermia remain to be elucidated. Therefore, in this brief overview we discuss both the clinical evidence and molecular mechanisms of therapeutic hypothermia in order to provide further insights into this promising intervention.

Preferential cephalic redistribution of left ventricular cardiac output during therapeutic hypothermia for perinatal hypoxic-ischemic encephalopathy

OBJECTIVE

To determine the relationship between left ventricular cardiac output (LVCO), superior vena cava (SVC) flow, and brain injury during whole-body therapeutic hypothermia.

STUDY DESIGN

Sixteen newborns with moderate or severe hypoxic-ischemic encephalopathy were studied using echocardiography during and immediately after therapeutic hypothermia. Measures were also compared with 12 healthy newborns of similar postnatal age. Newborns undergoing therapeutic hypothermia also had cerebral magnetic resonance imaging as part of routine clinical care on postnatal day 3-4.

RESULTS

LVCO was markedly reduced (mean ± SD 126 ± 38 mL/kg/min) during therapeutic hypothermia, whereas SVC flow was maintained within expected normal values (88 ± 27 mL/kg/min) such that SVC flow represented 70% of the LVCO. The reduction in LVCO during therapeutic hypothermia was mainly accounted by a reduction in heart rate (99 ± 13 vs 123 ± 17 beats/min; P < .001) compared with immediately postwarming in the context of myocardial dysfunction. Neonates with brain injury on magnetic resonance imaging had higher SVC flow prerewarming, compared with newborns without brain injury (P = .013).

CONCLUSION

Newborns with perinatal hypoxic-ischemic encephalopathy showed a preferential systemic-to-cerebral redistribution of cardiac blood flow during whole-body therapeutic hypothermia, which may reflect a lack of cerebral vascular adaptation in newborns with more severe brain injury.

Hypothermia for hypoxic-ischemic encephalopathy

Moderate to severe hypoxic-ischemic injury in newborn infants, manifested as encephalopathy immediately or within hours after birth, is associated with a high risk of either death or a lifetime with disability. In recent multicenter clinical trials, hypothermia initiated within the first 6 postnatal hours has emerged as a therapy that reduces the risk of death or impairment among infants with hypoxic-ischemic encephalopathy. Prior to hypothermia, no therapies directly targeting neonatal encephalopathy secondary to hypoxic-ischemic injury had convincing evidence of efficacy. Hypothermia therapy is now becoming increasingly available at tertiary centers. Despite the deserved enthusiasm for hypothermia, obstetric and neonatology caregivers, as well as society at large, must be reminded that in the clinical trials more than 40% of cooled infants died or survived with impairment. Although hypothermia is an evidence-based therapy, additional discoveries are needed to further improve outcome after HIE. In this article, we briefly present the epidemiology of neonatal encephalopathy due to hypoxic-ischemic injury, describe the rationale for the use of hypothermia therapy for hypoxic-ischemic encephalopathy, and present results of the clinical trials that have demonstrated the efficacy of hypothermia. We also present findings noted during and after these trials that will guide care and direct research for this devastating problem.

Becoming a parent to a child with birth asphyxia-From a traumatic delivery to living with the experience at home

The aim of this study is to describe the experiences of becoming a parent to a child with birth asphyxia treated with hypothermia in the neonatal intensive care unit (NICU). In line with the medical advances, the survival of critically ill infants with increased risk of morbidity is increasing. Children who survive birth asphyxia are at a higher risk of functional impairments, cerebral palsy (CP), or impaired vision and hearing. Since 2006, hypothermia treatment following birth asphyxia is used in many of the Swedish neonatal units to reduce the risk of brain injury. To date, research on the experience of parenthood of the child with birth asphyxia is sparse. To improve today's neonatal care delivery, health-care providers need to better understand the experiences of becoming a parent to a child with birth asphyxia. A total of 26 parents of 16 children with birth asphyxia treated with hypothermia in a Swedish NICU were interviewed. The transcribed interview texts were analysed according to a qualitative latent content analysis. We found that the experience of becoming a parent to a child with birth asphyxia treated with hypothermia at the NICU was a strenuous journey of overriding an emotional rollercoaster, that is, from being thrown into a chaotic situation which started with a traumatic delivery to later processing the difficult situation of believing the child might not survive or was to be seriously affected by the asphyxia. The prolonged parent-infant separation due to the hypothermia treatment and parents' fear of touching the infant because of the high-tech equipment seemed to hamper the parent-infant bonding. The adaption of the everyday life at home seemed to be facilitated by the follow-up information of the doctor after discharge. The results of this study underline the importance of family-centered support during and also after the NICU discharge.

Acupuncture for hypoxic ischemic encephalopathy in neonates

BACKGROUND

Hypoxic ischemic encephalopathy (HIE) in the neonate is associated with high mortality and morbidity. Effective treatment options are limited and therefore alternative therapies such as acupuncture are increasingly used.

OBJECTIVES

We sought to determine the efficacy and safety of acupuncture on mortality and morbidity in neonates with HIE.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library), Cochrane Neonatal Specialized Register, MEDLINE, AMED, EMBASE, PubMed, CINAHL, PsycINFO, WHO International Clinical Trials Registry Platform, and various Chinese medical databases in November 2012.

SELECTION CRITERIA

We planned to include randomized or quasi-randomized controlled trials comparing needle acupuncture to a control group that used no treatment, placebo or sham treatment in neonates (less than 28 days old) with HIE. Co-interventions were allowed as long as both the intervention and the control group received the same co-interventions. We excluded trials that evaluated therapy that did not involve penetration of the skin with a needle or trials that compared different forms of acupuncture only.

DATA COLLECTION AND ANALYSIS

Two review authors independently reviewed trials for inclusion. If trials were identified, the review authors planned to assess trial quality and extract data independently. We planned to use the risk ratio (RR), risk difference (RD), and number needed to benefit (NNTB) or harm (NNTH) with 95% confidence intervals (CI) for dichotomous outcomes, and mean difference (MD) with 95% CI for continuous outcomes.

MAIN RESULTS

No trial satisfied our predefined inclusion criteria. Existing trials only evaluated acupuncture in older infants who survived HIE. There are currently no randomized controlled trials evaluating the efficacy of acupuncture for treatment of HIE in neonates. The safety of acupuncture for HIE in neonates is unknown.

AUTHORS' CONCLUSIONS

The rationale for acupuncture in neonates with HIE is unclear and the evidence from randomized controlled trial is lacking. Therefore, we do not recommend acupuncture for the treatment of HIE in neonates. High quality randomized controlled trials on acupuncture for HIE in neonates are needed.

Spatial contrast sensitivity vision loss in children with cortical visual impairment

PURPOSE

Although cortical visual impairment (CVI) is the leading cause of bilateral vision impairment in children in Western countries, little is known about the effects of CVI on visual function. The aim of this study was to compare visual evoked potential measures of contrast sensitivity and grating acuity in children with CVI with those of age-matched typically developing controls.

METHODS

The swept parameter visual evoked potential (sVEP) was used to measure contrast sensitivity and grating acuity in 34 children with CVI at 5 months to 5 years of age and in 16 age-matched control children. Contrast thresholds and spatial frequency thresholds (grating acuities) were derived by extrapolating the tuning functions to zero amplitude. These thresholds and maximal suprathreshold response amplitudes were compared between groups.

RESULTS

Among 34 children with CVI, 30 had measurable but reduced contrast sensitivity with a median threshold of 10.8% (range 5.0%-30.0% Michelson), and 32 had measurable but reduced grating acuity with median threshold 0.49 logMAR (9.8 c/deg, range 5-14 c/deg). These thresholds were significantly reduced, compared with age-matched control children. In addition, response amplitudes over the entire sweep range for both measures were significantly diminished in children with CVI compared with those of control children.

CONCLUSIONS

Our results indicate that spatial contrast sensitivity and response amplitudes are strongly affected by CVI. The substantial degree of loss in contrast sensitivity suggests that contrast is a sensitive measure for evaluating vision deficits in patients with CVI.

Rescuing the neonatal brain from hypoxic injury with autologous cord blood

Brain injury resulting from perinatal hypoxic-ischemic encephalopathy (HIE) is a major cause of acute mortality in infants and chronic neurologic disability in surviving children. Recent multicenter clinical trials demonstrated the effectiveness of hypothermia initiated within the first 6 postnatal hours to reduce the risk of death or major neurological disabilities among neonates with HIE. However, in these trials, approximately 40% of cooled infants died or survived with significant impairments. Therefore, adjunct therapies are required to improve the outcome in neonates with HIE. Cord blood (CB) is a rich source of stem cells. Administration of human CB cells in animal models of HIE has generally resulted in improved outcomes and multiple mechanisms have been suggested including anti-inflammation, release of neurotrophic factors and stimulation of endogenous neurogenesis. Investigators at Duke are conducting studies of autologous CB infusion in neonates with HIE and in children with cerebral palsy. These pilot studies indicate no added risk from the regimens used, but results of ongoing placebo-controlled trials are needed to assess efficacy. Meanwhile, further investigations are warranted to determine the best strategies, that is, timing, dosing, route of delivery, choice of stem cells and ex vivo modulations, to attain long-term benefits of CB stem cell therapy.

Lessons learned during implementation of therapeutic hypothermia for neonatal hypoxic ischemic encephalopathy in a regional transport program in Ontario

BACKGROUND

Therapeutic hypothermia (TH) is the first intervention to consistently show improved neurological outcomes in neonates with hypoxic ischemic encephalopathy (HIE). Since the recent introduction of TH for HIE in many centres, reviews of practices during the implementation of TH in Canada have not been published.

OBJECTIVE

To determine if eligible neonates are being offered TH and to identify any barriers to the effective implementation of TH.

METHODS

A retrospective review of neonates referred to a regional tertiary centre at a gestational age of 35 weeks or more with HIE was conducted.

RESULTS

Among 41 neonates referred, 29 (71%) were eligible for TH; among eligible patients, five were moribund and excluded, and TH was initiated in 16 (67%) of the remaining 24. Reasons for not cooling in eight eligible patients included a delay in referral (n=5, median age at referral was 14 h) and a failure to recognize the severity of HIE (n=3). Among cooled patients, median times were the following: 116 min for age at referral; 80 min for time from referral to transport team arrival; and 358 min for age at initiation of cooling. Seven (44%) patients had cooling initiated after 6 h of age.

CONCLUSION

A significant proportion of eligible patients were not offered TH, and in many cooled patients, initiation of cooling was delayed beyond the recommended 6 h. For eligible patients to benefit from TH, it is imperative that all birthing centres be made aware that TH is now widely available as an important treatment option, but also that TH is a time-sensitive therapy requiring rapid identification and referral. In the region studied, for eligible patients, referring hospitals should initiate passive cooling before arrival of the transport team. Referring hospitals should be prepared to provide early, yet safe initiation of passive cooling by having the appropriate equipment, and having staff trained in the use and monitoring of rectal temperatures.

Dendrimer-based postnatal therapy for neuroinflammation and cerebral palsy in a rabbit model

Cerebral palsy (CP) is a chronic childhood disorder with no effective cure. Neuroinflammation, caused by activated microglia and astrocytes, plays a key role in the pathogenesis of CP and disorders such as Alzheimer's disease and multiple sclerosis. Targeting neuroinflammation can be a potent therapeutic strategy. However, delivering drugs across the blood-brain barrier to the target cells for treating diffuse brain injury is a major challenge. We show that systemically administered polyamidoamine dendrimers localize in activated microglia and astrocytes in the brain of newborn rabbits with CP, but not healthy controls. We further demonstrate that dendrimer-based N-acetyl-l-cysteine (NAC) therapy for brain injury suppresses neuroinflammation and leads to a marked improvement in motor function in the CP kits. The well-known and safe clinical profile for NAC, when combined with dendrimer-based targeting, provides opportunities for clinical translation in the treatment of neuroinflammatory disorders in humans. The effectiveness of the dendrimer-NAC treatment, administered in the postnatal period for a prenatal insult, suggests a window of opportunity for treatment of CP in humans after birth.

Allopurinol for preventing mortality and morbidity in newborn infants with hypoxic-ischaemic encephalopathy

BACKGROUND

Delayed neuronal death following a perinatal hypoxic insult is due partly to xanthine oxidase-mediated production of cytotoxic free radicals. Evidence exists that allopurinol, a xanthine-oxidase inhibitor, reduces delayed cell death in experimental models of perinatal asphyxia and in people with organ reperfusion injury.

OBJECTIVES

To determine the effect of allopurinol on mortality and morbidity in newborn infants with hypoxic-ischaemic encephalopathy.

SEARCH METHODS

We used the standard search strategy of the Cochrane Neonatal Group. We searched the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, 2012, Issue 1), MEDLINE (1966 to March 2012), EMBASE (1980 to March 2012), CINAHL (1982 to March 2012), conference proceedings, and previous reviews.

SELECTION CRITERIA

Randomised or quasi-randomised controlled trials that compared allopurinol administration versus placebo or no drug in newborn infants with hypoxic-ischaemic encephalopathy.

DATA COLLECTION AND ANALYSIS

We extracted data using the standard methods of the Cochrane Neonatal Review Group with separate evaluation of trial quality and data extraction by two review authors.

MAIN RESULTS

We included three trials in which a total of 114 infants participated. In one trial, participants were exclusively infants with severe encephalopathy. The other trials also included infants with mild and moderately severe encephalopathy. These studies were generally of good methodological quality, but were too small to exclude clinically important effects of allopurinol on mortality and morbidity. Meta-analysis did not reveal a statistically significant difference in the risk of death (typical risk ratio 0.88; 95% confidence interval (95% CI) 0.56 to 1.38; risk difference -0.04; 95% CI -0.18 to 0.10) or a composite of death or severe neurodevelopmental disability (typical risk ratio 0.78; 95% CI 0.56 to 1.08; risk difference -0.14; 95% CI -0.31 to 0.04).

AUTHORS' CONCLUSIONS

The available data are not sufficient to determine whether allopurinol has clinically important benefits for newborn infants with hypoxic-ischaemic encephalopathy. Much larger trials are needed. Such trials could assess allopurinol as an adjunct to therapeutic hypothermia in infants with moderate and severe encephalopathy and should be designed to exclude important effects on mortality and adverse long-term neurodevelopmental outcomes.

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.

Hypothermia attenuates the severity of oxidative stress development in asphyxiated newborns

PURPOSE

This retrospective case-control study aimed to examine the development of oxidative stress in asphyxiated infants delivered at more than 37 weeks of gestation.

MATERIAL AND METHODS

Thirty-seven neonates were stratified into 3 groups: the first group experienced hypothermia (n = 6); the second received hypothermia cooling cup treatment for 3 days, normothermia (n = 16); and the third was the control group (n = 15). Serum total hydroperoxide (TH), biological antioxidant potential, and oxidative stress index (OSI) (calculated as TH/biological antioxidant potential) were measured within 3 hours after birth.

RESULTS

Serum TH and OSI levels gradually increased after birth in hypothermia and normothermia cases. At all time points, serum TH and OSI levels were higher in hypothermia and normothermia cases than in control cases. Serum TH and OSI levels were higher in normothermia cases than in hypothermia cases at days 3, 5, and 7.

CONCLUSION

This study demonstrated that hypothermia attenuated the development of systemic oxidative stress in asphyxiated newborns.

[Neuroprotection with hypothermia in the newborn with hypoxic-ischaemic encephalopathy. Standard guidelines for its clinical application]

Standardisation of hypothermia as a treatment for perinatal hypoxic-ischaemic encephalopathy is supported by current scientific evidence. The following document was prepared by the authors on request of the Spanish Society of Neonatology and is intended to be a guide for the proper implementation of this therapy. We discuss the difficulties that may arise when moving from the strict framework of clinical trials to clinical daily care: early recognition of clinical encephalopathy, inclusion and exclusion criteria, hypothermia during transport, type of hypothermia (selective head or systemic cooling) and side effects of therapy. The availability of hypothermia therapy has changed the prognosis of children with hypoxic-ischaemic encephalopathy and our choices of therapeutic support. In this sense, it is especially important to be aware of the changes in the predictive value of the neurological examination and the electroencephalographic recording in cooled infants. In order to improve neuroprotection with hypothermia we need earlier recognition of to recognise earlier the infants that may benefit from cooling. Biomarkers of brain injury could help us in the selection of these patients. Every single infant treated with hypothermia must be included in a follow up program in order to assess neurodevelopmental outcome.

Brain temperature: heat production, elimination and clinical relevance

Neurological insults are a leading cause of morbidity and mortality, both in adults and especially in children. Among possible therapeutic strategies to limit clinical cerebral damage and improve outcomes, hypothermia remains a promising and beneficial approach. However, its advantages are still debated after decades of use. Studies in adults have generated conflicting results, whereas in children recent data even suggest that hypothermia may be detrimental. Is it because brain temperature physiology is not well understood and/or not applied properly, that hypothermia fails to convince clinicians of its potential benefits? Or is it because hypothermia is not, as believed, the optimal strategy to improve outcome in patients affected with an acute neurological insult? This review article should help to explain the fundamental physiological principles of brain heat production, distribution and elimination under normal conditions and discuss why hypothermia cannot yet be recommended routinely in the management of children affected with various neurological insults.

Early versus late MRI in asphyxiated newborns treated with hypothermia

OBJECTIVE

The purposes of this feasibility study were to assess: (1) the potential utility of early brain MRI in asphyxiated newborns treated with hypothermia; (2) whether early MRI predicts later brain injury observed in these newborns after hypothermia has been completed; and (3) whether early MRI indicators of brain injury in these newborns represent reversible changes.

PATIENTS AND METHODS

All consecutive asphyxiated term newborns meeting the criteria for therapeutic hypothermia were enrolled prospectively. Each newborn underwent one or two early MRI scans while receiving hypothermia, on day of life (DOL) 1 and DOL 2-3 and also one or two late MRI scans on DOL 8-13 and at 1 month of age.

RESULTS

37 MRI scans were obtained in 12 asphyxiated neonates treated with induced hypothermia. Four newborns developed MRI evidence of brain injury, already visible on early MRI scans. The remaining eight newborns did not develop significant MRI evidence of brain injury on any of the MRI scans. In addition, two patients displayed unexpected findings on early MRIs, leading to early termination of hypothermia treatment.

CONCLUSIONS

MRI scans obtained on DOL 2-3 during hypothermia seem to predict later brain injuries in asphyxiated newborns. Brain injuries identified during this early time appear to represent irreversible changes. Early MRI scans might also be useful to demonstrate unexpected findings not related to hypoxic-ischaemic encephalopathy, which could potentially be exacerbated by induced hypothermia. Additional studies with larger numbers of patients will be useful to confirm these results.

Drug-induced mild therapeutic hypothermia obtained by administration of a transient receptor potential vanilloid type 1 agonist

Background

The use of mechanical/physical devices for applying mild therapeutic hypothermia is the only proven neuroprotective treatment for survivors of out of hospital cardiac arrest. However, this type of therapy is cumbersome and associated with several side-effects. We investigated the feasibility of using a transient receptor potential vanilloid type 1 (TRPV1) agonist for obtaining drug-induced sustainable mild hypothermia.

Methods

First, we screened a heterogeneous group of TRPV1 agonists and secondly we tested the hypothermic properties of a selected candidate by dose-response studies. Finally we tested the hypothermic properties in a large animal. The screening was in conscious rats, the dose-response experiments in conscious rats and in cynomologus monkeys, and the finally we tested the hypothermic properties in conscious young cattle (calves with a body weight as an adult human). The investigated TRPV1 agonists were administered by continuous intravenous infusion.

Results

Screening: Dihydrocapsaicin (DHC), a component of chili pepper, displayed a desirable hypothermic profile with regards to the duration, depth and control in conscious rats. Dose-response experiments: In both rats and cynomologus monkeys DHC caused a dose-dependent and immediate decrease in body temperature. Thus in rats, infusion of DHC at doses of 0.125, 0.25, 0.50, and 0.75 mg/kg/h caused a maximal ΔT (°C) as compared to vehicle control of -0.9, -1.5, -2.0, and -4.2 within approximately 1 hour until the 6 hour infusion was stopped. Finally, in calves the intravenous infusion of DHC was able to maintain mild hypothermia with ΔT > -3°C for more than 12 hours.

Conclusions

Our data support the hypothesis that infusion of dihydrocapsaicin is a candidate for testing as a primary or adjunct method of inducing and maintaining therapeutic hypothermia.

Therapeutic hypothermia for newborn infants with hypoxic-ischaemic encephalopathy

Peripartum asphyxia complicated by moderate or severe hypoxic-ischaemic encephalopathy is a devastating global health issue. A therapeutic 'window of opportunity' exists after resuscitation of the asphyxiated newborn and before the delayed phase of neuronal loss. Animal studies demonstrated that neuronal injury following hypoxia-ischaemia can be prevented or reduced by a mild reduction in brain temperature. Human infant pilot studies confirmed feasibility, without major adverse effects. Randomised trials and systematic reviews comprising term infants with moderate or severe encephalopathy and peripartum asphyxia have established the neuroprotective benefit of therapeutic hypothermia. Hypothermia reduces mortality or major disability to 18 months of age, as well as cerebral palsy, and neuromotor and cognitive delay. Importantly, mortality is reduced without any increase in major neurodevelopmental disability in survivors, and with only minor adverse effects. The evidence supports therapeutic hypothermia when used within strict protocols in tertiary centres to improve the outcome for term and near-term newborns with moderate or severe hypoxic-ischaemic encephalopathy. Equally strict protocols in non-tertiary nurseries will enable earlier initiation of hypothermia under guidance of the regional neonatal intensive care unit and transport team.

Hypothermia: a systematic review and meta-analysis of clinical trials

Hypothermia is a potential neuroprotective intervention to treat neonatal post-asphyxial (hypoxic-ischemic) encephalopathy (HIE). In this meta-analysis of 13 clinical trials published to date, therapeutic hypothermia was associated with a highly reproducible reduction in the risk of the combined outcome of mortality or moderate-to-severe neurodevelopmental disability in childhood. This improvement was internally consistent, as shown by significant reductions in the individual risk for death, moderate-to-severe neurodevelopmental disability, severe cerebral palsy, cognitive delay, and psychomotor delay. Patients in the hypothermia group had higher incidences of arrhythmia and thrombocytopenia; however, these were not clinically important. This analysis supports the use of hypothermia in reducing the risk of the mortality or moderate-to-severe neurodevelopmental disability in infants with moderate HIE.

An overview of recent applications of computational modelling in neonatology

This paper reviews some of our recent applications of computational fluid dynamics (CFD) to model heat and mass transfer problems in neonatology and investigates the major heat and mass-transfer mechanisms taking place in medical devices, such as incubators, radiant warmers and oxygen hoods. It is shown that CFD simulations are very flexible tools that can take into account all modes of heat transfer in assisting neonatal care and improving the design of medical devices.

Hypothermia as a cytoprotective strategy in ischemic tissue injury

Hypothermia is a well established cytoprotectant, with remarkable and consistent effects demonstrated across multiple laboratories. At the clinical level, it has recently been shown to improve neurological outcome following cardiac arrest and neonatal hypoxia-ischemia. It is increasingly being embraced by the medical community, and could be considered an effective neuroprotectant. Conditions such as brain injury, hepatic encephalopathy and cardiopulmonary bypass seem to benefit from this intervention. It's role in direct myocardial protection is also being explored. A review of the literature has demonstrated that in order to appreciate the maximum benefits of hypothermia, cooling needs to begin soon after the insult, and maintained for relatively long period periods of time. In the case of ischemic stroke, cooling should ideally be applied in conjunction with the re-establishment of cerebral perfusion. Translating this to the clinical arena can be challenging, given the technical challenges of rapidly and stably cooling patients. This review will discuss the application of hypothermia especially as it pertains to its effects neurological outcome, cooling methods, and important parameters in optimizing hypothermic protection.

Postcardiac arrest syndrome: focus on the brain

PURPOSE OF REVIEW

The field of pediatric cardiac arrest experienced recent advances secondary to multicenter collaborations. This review summarizes developments during the last year and identifies areas for further research.

RECENT FINDINGS

A large retrospective review demonstrated important differences in cause, severity, and outcome of in-hospital vs. out-of-hospital pediatric cardiac arrest. This distinction is relevant to interpretation of retrospective studies that may not distinguish between these entities, and in planning therapeutic clinical trials. Hypothermia was further evaluated as a treatment strategy after neonatal hypoxia and leaders in the field of neonatology recommend universal use of hypothermia in term neonates at risk. In infants and children after cardiac arrest, there are inadequate data to make a specific recommendation. Two retrospective studies evaluating hypothermia in children after cardiac arrest found that it tended to be administered more frequently to sicker patients. However, similar or worse outcomes of patients treated with hypothermia were observed. Use of extracorporeal membrane oxygenation is another emerging area of research in pediatric cardiac arrest, and surprisingly good outcomes have been seen with this modality in some cases.

SUMMARY

Therapeutic hypothermia and extracorporeal membrane oxygenation continue to be the only treatment modalities over and above conventional care for pediatric cardiac arrest. New approaches to monitoring, treatment, and rehabilitation after cardiac arrest remain to be explored.

Neonatal resuscitation in low-resource settings: what, who, and how to overcome challenges to scale up?

BACKGROUND

Each year approximately 10 million babies do not breathe immediately at birth, of which about 6 million require basic neonatal resuscitation. The major burden is in low-income settings, where health system capacity to provide neonatal resuscitation is inadequate.

OBJECTIVE

To systematically review the evidence for neonatal resuscitation content, training and competency, equipment and supplies, cost, and key program considerations, specifically for resource-constrained settings.

RESULTS

Evidence from several observational studies shows that facility-based basic neonatal resuscitation may avert 30% of intrapartum-related neonatal deaths. Very few babies require advanced resuscitation (endotracheal intubation and drugs) and these newborns may not survive without ongoing ventilation; hence, advanced neonatal resuscitation is not a priority in settings without neonatal intensive care. Of the 60 million nonfacility births, most do not have access to resuscitation. Several trials have shown that a range of community health workers can perform neonatal resuscitation with an estimated effect of a 20% reduction in intrapartum-related neonatal deaths, based on expert opinion. Case studies illustrate key considerations for scale up.

CONCLUSION

Basic resuscitation would substantially reduce intrapartum-related neonatal deaths. Where births occur in facilities, it is a priority to ensure that all birth attendants are competent in resuscitation. Strategies to address the gap for home births are urgently required. More data are required to determine the impact of neonatal resuscitation, particularly on long-term outcomes in low-income settings.

Current and future role of therapeutic hypothermia

Therapeutic moderate hypothermia has been advocated for use in traumatic brain injury, stroke, cardiac arrest-induced encephalopathy, neonatal hypoxic-ischemic encephalopathy, hepatic encephalopathy, and spinal cord injury, and as an adjunct to aneurysm surgery. In this review, we address the trials that have been performed for each of these indications, and review the strength of the evidence to support treatment with mild/moderate hypothermia. We review the data to support an optimal target temperature for each indication, as well as the duration of the cooling, and the rate at which cooling is induced and rewarming instituted. Evidence is strongest for prehospital cardiac arrest and neonatal hypoxic-ischemic encephalopathy. For traumatic brain injury, a recent meta-analysis suggests that cooling may increase the likelihood of a good outcome, but does not change mortality rates. For many of the other indications, such as stroke and spinal cord injury, trials are ongoing, but the data are insufficient to recommend routine use of hypothermia at this time.

[Hypothermia for intracranial hypertension]

There is a large body of experimental evidence showing benefits of deliberate mild hypothermia (33-35 degrees C) on the injured brain as well as an improvement of neurological outcome after cardiac arrest in humans. However, the clinical evidence of any benefit of hypothermia following stroke, brain trauma and neonatal asphyxia is still lacking. Controversial results have been published in patients with brain trauma or neonatal asphyxia. Hypothermia can reduce the elevation of intracranial pressure, through mechanisms not completely understood. Hypothermia-induced hypocapnia should have a role on the reduction of intracranial pressure. The temperature target is unknown but no additional benefit was found below 34 degrees C. The duration of deliberate hypothermia for the treatment of elevated intracranial pressure might be at least 48 hours, and the subsequent rewarming period must be very slow to prevent adverse effects.

Neonatologie

Noch vor 10 Jahren war die häufigste Todesursache Frühgeborener das akute Lungenversagen. Die sensationellen Ergebnisse von Mary Ellen Avery ebneten dann den Weg für eine kausale Therapie des Atemnotsyndroms. M.E. Avery beobachtete, dass die Lungen eines verstorbenen Frühgeborenen luftleer und „schwer“ waren und kein „schäumendes Material“ („foam“)enthielten. Wiesie durch Experimente belegen konnte, fehlte diesen Lungen in der Tat eine Substanz, die die Oberflächenspannung in den Alveolen vermindert: das pulmonale Surfactant. Die 1959 publizierten Ergebnisse ihrer Untersuchungen fanden zunächst nicht die ihnen gebührende Aufmerksamkeit. Um die weitere Resonanz auf ihre Entdeckung zu beschreiben, verweist M.E. Avery gerne auf den deutschen Philosophen Schopenhauer. Dieser hatte erkannt, dass sich neues Wissen in 3 Phasen verbreitet: Die 1. Phase, in der neue Ergebnisse bekannt gegeben werden, wird meist ignoriert. In der 2. Phase rufen die inzwischen von anderen nicht mehr zu leugnenden Ergebnisse Feindseligkeiten hervor, in der 3. und letzten Phase besteht eine generelle Übereinstimmung darüber, dass man schon immervon dieser Tatsacheausgegangen sei.(CPS)

Hypothermia for hypoxic-ischemic encephalopathy

We are entering an era in which hypothermia will be used in combination with other novel neuroprotective interventions. The targeting of multiple sites in the cascade leading to brain injury may prove to be a more effective treatment strategy after hypoxic-ischemic encephalopathy in newborn infants than hypothermia alone.

Technical aspects of starting a neonatal cooling program

Clinicians who are convinced by the available evidence that cooling is a safe and effective treatment of hypoxic-ischemic encephalopathy in the term or near-term infant are now faced with a series of decisions around implementation of therapeutic hypothermia in their neonatal ICU or region. There is currently uncertainty about the efficacy of cooling or at least the magnitude of the effect, and precise estimates of the benefit of cooling must await the publication of the results of the several pending trials. This article assumes that clinicians are sufficiently convinced by the available evidence of safety and efficacy to proceed to the implementation step and offers guidelines for starting a neonatal cooling program.

Therapeutic hypothermia in neonates. Review of current clinical data, ILCOR recommendations and suggestions for implementation in neonatal intensive care units

Recent evidence suggests that the current ILCOR guidelines regarding hypothermia for the treatment of neonatal encephalopathy need urgent revision. In 2005 when the current ILCOR guidelines were finalised one large (CoolCap trial, n=235) and one small RCT (n=67), in addition to pilot trials, had been published, and demonstrated that therapeutic hypothermia after perinatal asphyxia was safe. The CoolCap trial showed a borderline overall effect on death and disability at 18 months of age, but significant improvement in a large subset of infants with less severe electroencephalographic changes. Based on this and other available evidence, the 2005 ILCOR guidelines supported post-resuscitation hypothermia in paediatric patients after cardiac arrest, but not after neonatal resuscitation. Subsequently, a whole body cooling trial supported by the NICHD reported a significant overall improvement in death or disability. Further large neonatal trials of hypothermia have stopped recruitment and their final results are likely to be published 2009-2011. Many important questions around the optimal therapeutic use of hypothermia remain to be answered. Nevertheless, independent meta-analyses of the published trials now indicate a consistent, robust beneficial effect of therapeutic hypothermia for moderate to severe neonatal encephalopathy, with a mean NNT between 6 and 8. Given that there is currently no other clinically proven treatment for infants with neonatal encephalopathy we propose that an interim advisory statement should be issued to support and guide the introduction of therapeutic hypothermia into routine clinical practice.

[Therapeutic hypothermia]

The use of therapeutic hypothermia has been shown to improve survival and neurological outcome following cardiac arrest. Patients with traumatic brain injury or ischemic stroke also responded positively to therapeutic hypothermia, which may be induced by various procedures including surface cooling, endovascular cooling catheter and cold infusion. Possible side effects include infection and hemorrhage, as well as changes in water and electrolyte levels. It is the aim of this article to provide an overview of studies to date, as well as practical guidance for the application of therapeutic hypothermia.

Allopurinol for preventing mortality and morbidity in newborn infants with suspected hypoxic-ischaemic encephalopathy

BACKGROUND

Delayed neuronal death following a perinatal hypoxic insult is due partly to xanthine oxidase-mediated production of cytotoxic free radicals. Evidence exists that allopurinol, a xanthine-oxidase inhibitor, reduces delayed cell death in animal models of perinatal asphyxia and in human patients with other forms of organ reperfusion injury.

OBJECTIVES

To determine the effect of allopurinol on mortality and morbidity in newborn infants with suspected hypoxic-ischaemic encephalopathy.

SEARCH STRATEGY

The standard search strategy of the Cochrane Neonatal Review Group was used. This included searches of the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, Issue 4, 2007), MEDLINE (1966 - December 2007), EMBASE (1980 - December 2007), conference proceedings, and previous reviews.

SELECTION CRITERIA

Randomised or quasi-randomised controlled trials that compared allopurinol administration vs. placebo or no drug in newborn infants with suspected hypoxic-ischaemic encephalopathy.

DATA COLLECTION AND ANALYSIS

The standard methods of the Cochrane Neonatal Review Group were used, with separate evaluation of trial quality and data extraction by two authors. Data were synthesised using a fixed effects model and reported using typical relative risk, typical risk difference and weighted mean difference.

MAIN RESULTS

Three trials in which a total of 114 infants participated were identified. In one trial, participants were exclusively infants with severe encephalopathy. The other trials also included infants with mild and moderately-severe encephalopathy. These studies were generally of good methodological quality, but were underpowered to detect clinically important effects of allopurinol on mortality and morbidity. Meta-analysis did not reveal a statistically significant difference in the risk of death during infancy [typical relative risk 0.92 (95% confidence interval 0.59 to 1.45); typical risk difference -0.03 (95% confidence interval -0.16 to 0.11)], nor in the incidence of neonatal seizures [typical relative risk 0.93 (95% confidence interval 0.75 to 1.16); typical risk difference -0.05 (95% confidence interval -0.21 to 0.11)]. Only one trial assessed neurodevelopment in surviving children and did not find a statistically significant effect.

AUTHORS' CONCLUSIONS

The available data are not sufficient to determine whether allopurinol has clinically important benefits for newborn infants with hypoxic-ischaemic encephalopathy and, therefore, larger trials are needed. Such trials could assess allopurinol as an adjunct to therapeutic hypothermia in infants with moderate and severe encephalopathy and should be designed to exclude clinically important effects on mortality and adverse long-term neurodevelopmental outcomes.

Current controversies in hypothermic neuroprotection

In 2005, three randomised controlled trials (RCTs) showed that treating infants with hypoxic-ischaemic encephalopathy (HIE) with hypothermia decreased the combined outcome of death or disability at 12-18 months, although treatment effects were modest. More recently, the US Food and Drug Administration (FDA) approved a device for selective head cooling. In addition, the protocol from another of the three trials, using equipment available in many hospitals, has been in the public domain for over a year. Why has this not led to a consensus that hypothermia is the standard of care for HIE? This is explored. Important questions for future research will focus on ways to improve on initial results with cooling, such as drug plus hypothermia combination therapy and refining duration and depth of cooling or duration of rewarming. Although the latter are important questions for future clinical trials, those who are convinced by the evidence to date should focus on safe implementation of cooling using protocols with established safety and efficacy and should consider ways to increase access to cooling for eligible babies.

Therapeutic hypothermia changes the prognostic value of clinical evaluation of neonatal encephalopathy

OBJECTIVE

To evaluate whether therapeutic hypothermia alters the prognostic value of clinical grading of neonatal encephalopathy.

STUDY DESIGN

This study was a secondary analysis of a multicenter study of 234 term infants with neonatal encephalopathy randomized to head cooling for 72 hours starting within 6 hours of birth, with rectal temperature maintained at 34.5 degrees C +/- 0.5 degrees C, followed by re-warming for 4 hours, or standard care at 37.0 degrees C +/- 0.5 degrees C. Severity of encephalopathy was measured pre-randomization and on day 4, after re-warming, in 177 infants; 31 infants died before day 4, and data were missing for 10 infants. The primary outcome was death or severe disability at 18 months of age.

RESULTS

Milder pre-randomization encephalopathy, greater improvement in encephalopathy from randomization to day 4, and cooling were associated with favorable outcome in multivariate binary logistic regression. Hypothermia did not affect severity of encephalopathy at day 4, however, in infants with moderate encephalopathy at day 4, those treated with hypothermia had a significantly higher rate of favorable outcome (31/45 infants, 69%, P = .006) compared with standard care (12/33, 36%).

CONCLUSION

Infants with moderate encephalopathy on day 4 may have a more favorable prognosis after hypothermia treatment than expected after standard care.

Bench to bedside strategies for optimizing neuroprotection following perinatal hypoxia-ischaemia in high and low resource settings

BACKGROUND

Therapeutic hypothermia gathers impetus in the developed world as a safe and effective therapy for term asphyxial encephalopathy. Although many questions still remain about the optimal application of hypothermic neuroprotection it is difficult to ignore the developing world where the prevalence of asphyxial encephalopathy is much higher. Experimental studies to optimize high tech cooling need to run in parallel with trials to determine the possible benefits of therapeutic hypothermia in low resource settings.

METHODS

We used a validated newborn piglet model of transient HI to determine (i) whether optimal neuroprotection occurs at different temperatures in the cortical and deep grey matter; (ii) the effect of body size on regional brain temperature under normothermia and hypothermia; (iii) the effect of insult severity on the therapeutic window duration; (iv) whether cooling using a water bottle is feasible. In this model hypoxia-ischaemia is induced by reversible occlusion of the common carotid arteries by remotely controlled vascular occluders and simultaneous reduction in the inspired oxygen fraction to 0.12. Intensive care can be administered to the piglet maintaining metabolic and physiological homeostasis throughout the experiment, and cerebral energy metabolism is monitored continuously providing quantitative measures of the HI insult, latent phase and secondary energy failure using phosphorus-31 ((31)P) magnetic resonance spectroscopy (MRS).

RESULTS

(i) The optimal temperature for cooling was lower in the cortex than deep grey matter. (ii) Cerebral temperatures were body-weight dependent: a smaller body weight led to a lower brain temperature especially with selective head cooling. (iii) Latent-phase duration is inversely related to insult severity. (iv) Low tech, simple cooling methods using a water bottle can induce and maintain moderate hypothermia.

CONCLUSIONS

Small shifts in brain temperature critically influence the survival of neuronal cells and body size critically influences brain-temperature gradients - smaller subjects have a larger surface area to brain volume and hence more heat is lost. The clinical implication is that smaller infants may require higher cap or body temperatures to avoid detrimental effects of over-zealous cooling. Latent-phase brevity may explain less effective neuroprotection following severe HI in some clinical studies. "Tailored" treatments which take into account individual and regional characteristics may increase the effectiveness of therapeutic hypothermia in the developed world. Low tech cooling methods using water bottles may be feasible although adequate staffing and monitoring would be required.