Hypothermia reduces seizure burden and improves neurological outcome in severe hypoxic-ischemic encephalopathy: an observational study

Association Between Seizures and Neurodevelopmental Outcome at Two and Five Years in Asphyxiated Newborns With Therapeutic Hypothermia

OBJECTIVE

To investigate the association between the presence and severity of seizures in asphyxiated newborns and their neurodevelopmental outcome at ages two and five years.

METHODS

Retrospective data analysis from a prospectively collected multicenter cohort of 186 term-born asphyxiated newborns undergoing therapeutic hypothermia (TH) in 11 centers in the Netherlands and Belgium. Seizures were diagnosed by amplitude-integrated electroencephalography (EEG) and raw EEG signal reading up to 48 hours after rewarming. Neurodevelopmental outcome was assessed by standardized testing at age two and five years. Primary outcome was death or long-term neurodevelopmental impairment (NDI) including cerebral palsy. Associations were calculated using univariate and multivariate logistic regression analyses adjusting for Thompson score and a validated brain magnetic resonance imaging (MRI) score.

RESULTS

Seventy infants (38%) had seizures during TH or rewarming, and 44 (63%) of these needed two or more antiseizure medications (ASMs). Overall mortality was 21%. Follow-up data from 147 survivors were available for 137 infants (93%) at two and for 94 of 116 infants (81%) at five years. NDI was present in 26% at two and five years. Univariate analyses showed a significant association between seizures and death or NDI, but this was no longer significant after adjusting for Thompson and MRI score in the multivariate analysis; this was also true for severe seizures (need for two or more ASMs) or seizures starting during rewarming.

CONCLUSION

The presence or severity of seizures in newborns undergoing TH for hypoxic-ischemic encephalopathy was not independently associated with death or NDI up to age five years after adjusting for several confounders.

Neurodevelopmental outcome of neonatal seizures: A longitudinal study

INTRODUCTION

Neonatal seizures (NS) are the most common neurological emergency in the neonatal period. The International League Against Epilepsy (ILAE) proposed a new classification of NS based on semiology and highlighted the correlation between semiology and aetiology. However, neurodevelopmental outcomes have not been comprehensively evaluated based on this new classification.

AIMS

To evaluate neurodevelopmental outcomes and potential risk factors for severe outcomes in NS.

METHODS

Patients with video electroencephalogram confirmed NS were evaluated. Seizure aetiology, cerebral magnetic resonance imaging (MRI) data, background electroencephalograms data, general movements, and neurodevelopmental outcomes were analysed. Severe outcomes were one of the following: death, cerebral palsy, Griffiths developmental quotient <70, epilepsy, deafness, or blindness.

RESULTS

A total of 74 neonates were evaluated: 62 (83.8 %) with acute provoked NS (primarily hypoxic-ischaemic encephalopathy), and 12 (16.2 %) with neonatal-onset epilepsies (self-limited neonatal epilepsy, developmental and epileptic encephalopathy, cerebral malformations). Of these, 32 (43.2 %) had electrographic seizures, while 42 (56.7 %) had electroclinical seizures - 38 (90.5 %) were motor (42.1 % clonic) and 4 (9.5 %) were non-motor phenomena. Severe outcomes occurred in 33 of the 74 (44.6 %) participants. In multivariate analysis, neonatal-onset epilepsies (odds ratio [OR]: 1.3; 95 % confidence interval [CI]: 1.1-1.6), status epilepticus (OR: 5.4; 95 % CI: 1.5-19.9), and abnormal general movements (OR: 3.4; 95 % CI: 1.9-7.6) were associated with severe outcomes.

CONCLUSIONS

At present, hypoxic-ischaemic encephalopathy remains the most frequent aetiology of NS. The prognosis of neonatal-onset epilepsies was worse than that of acute provoked NS, and status epilepticus was the most predictive factor for adverse outcomes.

The Association of Therapeutic Hypothermia With Seizure Burden in Neonates With Hypoxic-Ischemic Encephalopathy

OBJECTIVES

To compare seizure burden between newborn infants treated with therapeutic hypothermia (TH) and those that were not and to compare the need for antiseizure medications (ASM) in a cohort of infants who were diagnosed with neonatal hypoxic-ischemic encephalopathy (HIE).

METHODS

This was a retrospective cohort study on infants born after 35 weeks' gestation, diagnosed with moderate to severe HIE, monitored with amplitude-integrated electroencephalography (aEEG) and eligible for TH. Infants born before the implementation of TH in 2008 were compared with infants born thereafter who received TH. Seizure burden was assessed from aEEG as total time in minutes of seizures activity per hour of recording. Other clinical and demographic data were retrieved from a prospective local database of infants with HIE.

RESULTS

Overall, 149 of 207 infants were included in the study: 112 exposed to TH and 37 not exposed. Cooled infants had a lower seizure burden overall (0.4 vs 2.3 min/h, P < 0.001) and were also less likely to be treated with ASM (74% vs 100%, P < 0.001). In multivariable regression models, not exposed to TH, having a depressed aEEG background, and having higher Apgar scores were associated with higher seizure burden (incidence rate ratio: 4.78 for noncooled infants, P < 0.001); also, not exposed to TH was associated with a higher likelihood of multidrug ASM (odds ratio: 4.83, P < 0.001).

CONCLUSIONS

TH in infants with moderate to severe HIE is associated with significant reduction of seizure burden and ASM therapy.

Analgesia and sedation strategies in neonates undergoing whole-body therapeutic hypothermia: A scoping review

BACKGROUND

Therapeutic hypothermia (TH) is a widely practiced neuroprotective strategy for neonates with hypoxic-ischemic encephalopathy. Induced hypothermia is associated with shivering, cold pain, agitation, and distress.

OBJECTIVE

This scoping review determines the breadth of research undertaken for pain and stress management in neonates undergoing hypothermia therapy, the pharmacokinetics of analgesic and sedative medications during hypothermia and the effect of such medication on short- and long-term neurological outcomes.

METHODS

We searched the following online databases namely, (i) MEDLINE, (ii) Web of Science, (iii) Cochrane Library, (iv) Scopus, (v) CINAHL, and (vi) EMBASE to identify published original articles between January 2005 and December 2022. We included only English full-text articles on neonates treated with TH and reported the sedation/analgesia strategy used. We excluded articles that reported TH on transport or extracorporeal membrane oxygenation, did not report the intervention strategies for sedation/analgesia, and reported hypoxic-ischemic encephalopathy in which hypothermia was not applied.

RESULTS

The eligible publications (n = 97) included cohort studies (n = 72), non-randomized experimental studies (n = 2), pharmacokinetic studies (n = 4), dose escalation feasibility trial (n = 1), cross-sectional surveys (n = 5), and randomized control trials (n = 13). Neonatal Pain, Agitation, and Sedation Scale (NPASS) is the most frequently used pain assessment tool in this cohort. The most frequently used pharmacological agents are opioids (Morphine, Fentanyl), benzodiazepine (Midazolam) and Alpha2 agonists (Dexmedetomidine). The proportion of neonates receiving routine sedation-analgesia during TH is center-specific and varies from 40-100% worldwide. TH alters most drugs' metabolic rate and clearance, except for Midazolam. Dexmedetomidine has additional benefits of thermal tolerance, neuroprotection, faster recovery, and less likelihood of seizures. There is a wide inter-individual variability in serum drug levels due to the impact of temperature, end-organ dysfunction, postnatal age, and body weight on drug metabolism.

CONCLUSIONS

No multidimensional pain scale has been tested for reliability and construct validity in hypothermic encephalopathic neonates. There is an increasing trend towards using routine sedation/analgesia during TH worldwide. Wide variability in the type of medication used, administration (bolus versus infusion), and dose ranges used emphasizes the urgent need for standardized practice recommendations and guidelines. There is insufficient data on the long-term neurological outcomes of exposure to these medications, adjusted for underlying brain injury and severity of encephalopathy. Future studies will need to develop framework tools to enable precise control of sedation/analgesia drug exposure customized to individual patient needs.

Treatment of seizures in the neonate: Guidelines and consensus-based recommendations-Special report from the ILAE Task Force on Neonatal Seizures

Seizures are common in neonates, but there is substantial management variability. The Neonatal Task Force of the International League Against Epilepsy (ILAE) developed evidence-based recommendations about antiseizure medication (ASM) management in neonates in accordance with ILAE standards. Six priority questions were formulated, a systematic literature review and meta-analysis were performed, and results were reported following the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analyses) 2020 standards. Bias was evaluated using the Cochrane tool and risk of Bias in non-randomised studies - of interventions (ROBINS-I), and quality of evidence was evaluated using grading of recommendations, assessment, development and evaluation (GRADE). If insufficient evidence was available, then expert opinion was sought using Delphi consensus methodology. The strength of recommendations was defined according to the ILAE Clinical Practice Guidelines development tool. There were six main recommendations. First, phenobarbital should be the first-line ASM (evidence-based recommendation) regardless of etiology (expert agreement), unless channelopathy is likely the cause for seizures (e.g., due to family history), in which case phenytoin or carbamazepine should be used. Second, among neonates with seizures not responding to first-line ASM, phenytoin, levetiracetam, midazolam, or lidocaine may be used as a second-line ASM (expert agreement). In neonates with cardiac disorders, levetiracetam may be the preferred second-line ASM (expert agreement). Third, following cessation of acute provoked seizures without evidence for neonatal-onset epilepsy, ASMs should be discontinued before discharge home, regardless of magnetic resonance imaging or electroencephalographic findings (expert agreement). Fourth, therapeutic hypothermia may reduce seizure burden in neonates with hypoxic-ischemic encephalopathy (evidence-based recommendation). Fifth, treating neonatal seizures (including electrographic-only seizures) to achieve a lower seizure burden may be associated with improved outcome (expert agreement). Sixth, a trial of pyridoxine may be attempted in neonates presenting with clinical features of vitamin B6-dependent epilepsy and seizures unresponsive to second-line ASM (expert agreement). Additional considerations include a standardized pathway for the management of neonatal seizures in each neonatal unit and informing parents/guardians about the diagnosis of seizures and initial treatment options.

Continuous Fentanyl Infusion in Newborns with Hypoxic-Ischemic Encephalopathy Treated with Therapeutic Hypothermia: Background, Aims, and Study Protocol for Time-Concentration Profiles

Therapeutic hypothermia (TH) is the standard of care for newborns with moderate to severe hypoxic-ischemic encephalopathy (HIE). Discomfort and pain during treatment are common and may affect the therapeutic efficacy of TH. Opioid sedation and analgesia (SA) are generally used in clinical practice, and fentanyl is one of the most frequently administered drugs. However, although fentanyl's pharmacokinetics (PKs) may be altered by hypothermic treatment, the PK behavior of this opioid drug in cooled newborns with HIE has been poorly investigated. The aim of this phase 1 study protocol (Trial ID: FentanylTH; EUDRACT number: 2020-000836-23) is to evaluate the fentanyl time-concentration profiles of full-term newborns with HIE who have been treated with TH. Newborns undergoing TH receive a standard fentanyl regimen (2 mcg/Kg of fentanyl as a loading dose, followed by a continuous infusion-1 mcg/kg/h-during the 72 h of TH and subsequent rewarming). Fentanyl plasma concentrations before bolus administration, at the end of the loading dose, and 24-48-72-96 h after infusion are measured. The median, maximum, and minimum plasma concentrations, together with drug clearance, are determined. This study will explore the fentanyl time-concentration profiles of cooled, full-term newborns with HIE, thereby helping to optimize the fentanyl SA dosing regimen during TH.

Hypoxic-Ischemic Encephalopathy: Changing Outcomes Across the Spectrum

Neonatal hypoxic-ischemic encephalopathy (HIE) is a leading cause of death and neurodevelopmental impairment in neonates. Therapeutic hypothermia (TH) is the only established effective therapy and randomized trials affirm that TH reduces death and disability in moderate-to-severe HIE. Traditionally, infants with mild HIE were excluded from these trials due to the perceived low risk for impairment. Recently, multiple studies suggest that infants with untreated mild HIE may be at significant risk of abnormal neurodevelopmental outcomes. This review will focus on the changing landscape of TH, the spectrum of HIE presentations and their neurodevelopmental outcomes.

Neuroprotective therapies in the NICU in term infants: present and future

Outcomes of neonatal encephalopathy (NE) have improved since the widespread implementation of therapeutic hypothermia (TH) in high-resource settings. While TH for NE in term and near-term infants has proven beneficial, 30-50% of infants with moderate-to-severe NE treated with TH still suffer death or significant impairments. There is therefore a critical need to find additional pharmacological and non-pharmacological interventions that improve the outcomes for these children. There are many potential candidates; however, it is unclear whether these interventions have additional benefits when used with TH. Although primary and delayed (secondary) brain injury starting in the latent phase after HI are major contributors to neurodisability, the very late evolving effects of tertiary brain injury likely require different interventions targeting neurorestoration. Clinical trials of seizure management and neuroprotection bundles are needed, in addition to current trials combining erythropoietin, stem cells, and melatonin with TH. IMPACT: The widespread use of therapeutic hypothermia (TH) in the treatment of neonatal encephalopathy (NE) has reduced the associated morbidity and mortality. However, 30-50% of infants with moderate-to-severe NE treated with TH still suffer death or significant impairments. This review details the pathophysiology of NE along with the evidence for the use of TH and other beneficial neuroprotective strategies used in term infants. We also discuss treatment strategies undergoing evaluation at present as potential adjuvant treatments to TH in NE.

Polygraphic EEG Can Identify Asphyxiated Infants for Therapeutic Hypothermia and Predict Neurodevelopmental Outcomes

Background: Neonatal encephalopathy due to perinatal asphyxia is one of the leading causes of neonatal death and morbidity worldwide. The neurodevelopmental outcomes of asphyxiated neonates have considerably improved after therapeutic hypothermia (TH). The current challenge is to identify all newborns with encephalopathy at risk of cerebral lesions and subsequent disability within 6 h of life and who may be within the window period for treatment with TH. This study evaluated the neurodevelopmental outcomes in surviving asphyxiated neonates who did and did not receive TH, based on clinical and polygraphic electroencephalographic (p-EEG) criteria. Methods: The study included 139 asphyxiated newborns divided into two groups: 82 who received TH and 57 who were not cooled. TH was administered to asphyxiated newborns (gestational age ≥ 35 weeks, birth weight ≥ 1800 g) with encephalopathy of any grade and moderate-to-severe p-EEG abnormalities or seizures. Neurodevelopmental outcomes between the groups at 24 months of life and the risk factors for severe outcomes were assessed. Results: Severe neurodevelopmental impairment occurred in 10 (7.2%) out of the 139 enrolled neonates. Nine out of the 82 cooled neonates (11.0%) had severe neurodevelopmental impairment. All but one neonate (98.2%) who did not receive TH had normal outcomes. The multivariate logistic regression analysis showed that abnormal p-EEG patterns (OR: 27.6; IC: 2.8-267.6) and general movements (OR: 3.2; IC: 1.0-10.0) were significantly associated with severe neurodevelopmental impairment (area under ROC curve: 92.7%). Conclusion: The combination of clinical and p-EEG evaluations in hypoxic-ischemic encephalopathy contributed to a more accurate selection of patients treated with therapeutic hypothermia. When administered to infants with moderate to severe p-EEG abnormalities, TH prevents approximately 90% of severe neurodevelopmental impairment after any grade of hypoxic-ischemic encephalopathy.

Neonatal seizures treatment based on conventional multichannel EEG monitoring: an overview of therapeutic options

INTRODUCTION

Seizures are the main neurological emergency during the neonatal period and are mostly acute and focal. The prognosis mainly depends on the underlying etiology. Conventional multichannel video-electroencephalographic (cEEG) monitoring is the gold standard for diagnosis, but treatment remains a challenge.

AREAS COVERED

: This review, based on PubMed search over the last 4 decades, focuses on the current treatment options for neonatal seizures based on cEEG monitoring. There is still no consensus on seizure therapy, owing to poor scientific evidence. Traditionally, the first-line treatments are phenobarbital and phenytoin, followed by midazolam and lidocaine, but their efficacy is limited. Therefore, current evidence strongly suggests the use of alternative antiseizure medications. Randomized controlled trials of new drugs are ongoing.

EXPERT OPINION

: Therapy for neonatal seizures should be prompt and tailored, based on semeiology, mirror of the underlying cause, and cEEG features. Further research should focus on antiseizure medications that directly act on the etiopathogenetic mechanism responsible for seizures and are therefore more effective in seizure control.

Fentanyl analgesia in asphyxiated newborns treated with therapeutic hypothermia

INTRODUCTION

Therapeutic hypothermia is the standard care for asphyxiated newborns. Discomfort and pain during treatment are common and may affect therapeutic efficacy of hypothermia. Opioid analgosedation is commonly used in the clinical setting, but its effects in the cooled newborns is poorly investigated.

OBJECTIVE

The aim of this study was to assess the safety of fentanyl analgosedation during therapeutic hypothermia, by evaluating severe adverse effects and possible correlation with the neurodevelopmental outcome.

METHODS

We analyzed asphyxiated newborns treated with hypothermia receiving fentanyl intravenous infusion (years 2013-2018). Severe neurodevelopmental outcome was defined as cerebral palsy or Griffith's developmental quotient <70 or major sensorineural deficit. Severe brain lesions were defined as cortical or/and basal ganglia extensive involvement.

RESULTS

Fentanyl cumulative dose was variable (61.7 ± 18.5 µg/kg; range 34.3-120.3 µg/kg) among 45 enrolled patients. Respiratory depression was recorded in 13.3% cases of 30 spontaneously breathing patients. Severe brain lesions and severe neurodevelopmental disability were found in 24.4 and 11.1% of all included cases, respectively. Higher cumulative fentanyl dose was not associated with poor outcome.

CONCLUSIONS

Fentanyl treatment during therapeutic hypothermia does not negatively affect the neurodevelopmental outcome, thus on the contrary, it may contribute to ameliorate neuroprotection in the asphyxiated cooled newborns.

Neonatal Antiepileptic Medication Treatment Patterns: A Decade of Change

OBJECTIVE

This study aims to describe the frequency and characteristics of anticonvulsant medication treatments initiated in the neonatal period.

STUDY DESIGN

We analyzed a cohort of neonates with a seizure diagnosis who were discharged from institutions in the Pediatric Health Information System between 2007 and 2016. Adjusted risk ratios and 95% confidence intervals for characteristics associated with neonatal (≤ 28 days postnatal) anticonvulsant initiation were calculated via modified Poisson regression.

RESULTS

A total of 6,245 infants from 47 institutions were included. There was a decrease in both phenobarbital initiation within the neonatal period (96.9 to 91.3%, p = 0.015) and continuation at discharge (90.6 to 68.6%, p <0.001). Levetiracetam (7.9 to 39.6%, p < 0.001) initiation within the neonatal period and continuation at discharge (9.4 to 49.8%, p < 0.001) increased. Neonates born at ≥ 37 weeks' gestation and those diagnosed with intraventricular hemorrhage, ischemic/thrombotic stroke, other hemorrhagic stroke, and hypoxic ischemic encephalopathy (HIE) had a higher probability of anticonvulsant administration. The most prevalent diagnosis was HIE (n = 2,223, 44.4%).

CONCLUSION

Phenobarbital remains the most widely used neonatal seizure treatment. Levetiracetam is increasingly used as a second line therapy. Increasing levetiracetam use indicates a need for additional study to determine its effectiveness in reducing seizure burden and improving long-term outcomes.

Biomarkers in newborns with hypoxic-ischemic encephalopathy treated with therapeutic hypothermia

PURPOSE

The aim of the presented study was to evaluate the differences between selected biochemical markers in infants with moderate or severe hypoxic-ischemic encephalopathy (HIE) and their impact on patient prognosis.

METHODS

A total of 57 cooled newborns were divided into groups according to Sarnat staging of HIE (A, moderate vs. B, severe). The differences between groups were evaluated depending on the mode of delivery, pregnancy and labor complications, gestational age at birth, birth weight, and Apgar score at 1.3 and 5 min. The differences in biochemical biomarkers of HIE (pH, base excess, serum lactate) as well as biomarkers of hepatic injury (aspartate transaminase, (AST), alanine transaminase (ALT), prothrombin time (PT), and activated partial thromboplastin time (APTT)), kidney failure (creatinine, urea), myocardial injury (troponin T (TnT)), levels of fibrinogen, and platelet counts were also examined. Univariate Kaplan-Meier method was used for survival analyses.

RESULTS

The biomarker levels in severe HIE newborns compared with moderate were as follows: pH (7.10 vs. 6.99), serum lactate (22.50 vs. 17.00 mg/dL), AST (109.50 vs. 270.55 IU/L), ALT (27.30 vs. 108.05 IU/L), PT (17.00 vs. 44.20 s), APTT (47.75 vs. 47.90 s), TnT (0.22 vs. 0.85 ng/mL), creatinine (0.68 vs. 1.15 mg/dL), urea (44.55 vs. 73.30 mg/dL), and fibrinogen (1.65 vs. 1.90 mg/dL). Survival analyses showed significantly reduced survival for severe HIE infants (75%) vs. moderate HIE (100%).

CONCLUSION

In conclusion, the severity of HIE can be evaluated based on selected markers; however, their levels do not correspond with future prognosis of newborns.

Seizure burden and neurodevelopmental outcome in newborns with hypoxic-ischemic encephalopathy treated with therapeutic hypothermia: A single center observational study

OBJECTIVE

To examine the relationship between electrographic seizures and developmental outcome at 18 and 24 months in neonates with moderate and severe hypoxic-ischemic encephalopathy [HIE] treated with therapeutic hypothermia [TH].

STUDY DESIGN

30 term infants with moderate-severe HIE treated with TH were enrolled prospectively from June 2012 to May 2018. All had continuous single channel amplitude integrated EEG (aEEG) monitoring for a minimum of 72 h and brain MR within 4 weeks. The aEEG was classified by severity of background and seizure burden. MR images were graded by the severity of injury. Outcome (defined abnormal in case of death, dyskinetic or spastic quadriplegic cerebral palsy, epilepsy, or Bayley III score < 85 in all three subscales or < 70 in any individual subscale) was assessed at 18 and 24 months.

RESULTS

Seizures were recorded in 24 out of 30 [80 %] neonates and an abnormal outcome was observed in 7 [23 %] of infants. Patients with poor outcome had a statistically significant correlation with: high seizure burden (p = 0.0004), need for more than one antiepileptic drugs (p = 0.006), a persistent abnormal aEEG trace at 48 h (p = 0.0001) and moderate-severe brain injury at MRI (p = 0.0001). Moreover, infants with status epilepticus or frequent seizures reported a significantly association with abnormal MR imaging and poor outcome than patients with sporadic seizures (p = 0.0009).

CONCLUSION

The role of seizures in the pathogenesis of brain injury remains controversial. In our cohort the presence of seizures, per se, was not associated with abnormal outcome; however a high seizure burden as well as a persistent abnormal aEEG background pattern and MR lesions resulted significantly associated with poor prognosis.

Therapeutic hypothermia for pediatric refractory status epilepticus May Ameliorate post-status epilepticus epilepsy

BACKGROUND

To compare the clinical characteristics and outcomes of pediatric patients with refractory status epilepticus (RSE) and super-refractory status epilepticus (SRSE) who received therapeutic hypothermia (TH) plus anticonvulsants or anticonvulsants alone.

METHODS

Two-medical referral centers, retrospective cohort study. Pediatric Intensive Care Unit (PICU) at Taoyuan Chang Gung Children's hospital and Kaohsiung Chang Gung Memorial Hospital. We reviewed the medical records of 23 patients with RSE/SRSE who were admitted to PICU from January 2014 to December 2017. Of these, 11 patients received TH (TH group) and 12 patients did not (control group).

RESULTS

The selective endpoints were RSE/SRSE duration, length of PICU stay, and Glasgow Outcome Scale (GOS) score. We applied TH using the Artic Sun® temperature management system (target temperature, 34-35 °C; duration, 48-72 h). Of the 11 patients who received TH, 7 had febrile infection-related epilepsy syndrome (FIRSE), one had Dravet syndrome, and three had traumatic brain injury. The TH group had significantly shortern seizure durations than did the control group (hrs; median (IQR) 24(40) vs. 96(90), p < 0.05). Two patients in the TH group died of pulmonary embolism and extreme brain edema. The length of PICU stay was similar between the groups (days; median (IQR) 30(42) v.s 30.5(30.25)). The TH group had significantly better long-term outcomes than did the control group (GOS score, median (IQR) 4(2) v.s 3 (0.75), p = 0.01∗). The TH group had a significantly lower incidence of later chronic refractory epilepsy than did the control group (TH v.s non-TH, 5/11 (45%) v.s. 12/12(100%), p < 0.01).

CONCLUSIONS

TH effectively reduced the seizure burden in patients with RSE/SRSE. Our findings support that for patients with RSE/SRSE, TH shortens the seizure duration, ultimately reducing the occurrence of post-status epilepticus epilepsy and improving patients' long-term survival.

Pseudo-sawtooth pattern on amplitude-integrated electroencephalography in neonatal hypoxic-ischemic encephalopathy

OBJECTIVE

The objective of this study was to describe a novel amplitude-integrated electroencephalography (aEEG) pattern in infants with hypoxic-ischemic encephalopathy (HIE) and to assess the clinical significance.

METHODS

The aEEG traces of infants with HIE who were treated with therapeutic hypothermia (TH) from 2012 to 2017 were analyzed. A pseudo-sawtooth (PST) pattern was defined as a periodic increase of the upper and/or lower margin of the trace on aEEG without showing seizure activities on conventional EEG (CEEG).

RESULTS

Of the 46 infants, 6 (13%) had the PST pattern. The PST pattern appeared following a flat trace or a continuous low-voltage pattern and was followed by a burst-suppression pattern. On CEEG, the PST pattern consists of alternating cycles of low-voltage irregular activities and almost flat tracing. The PST pattern was associated with neuroimaging abnormalities and with various degrees of neurodevelopmental outcomes. Positive predictive values of the PST or worse pattern for adverse outcomes were high at 12 h after birth.

CONCLUSION

A novel aEEG background pattern in infants with HIE was reported. The PST pattern likely indicates a suppressed background pattern and may be linked to unfavorable outcomes. Further multicenter validation study is needed to clarify its clinical significance.

What is new: Talk about status epilepticus in the neonatal period

Nowadays, no general consensus was achieved regarding neonatal status epilepticus and its definition. Indeed, different criteria (mainly based on seizure duration) were used. Whereas a recent proposal has been developed to define status epilepticus in older ages, it seems that the peculiar characteristics of neonatal seizures and of the immature brain make difficult to find a tailored definition for this period of life. Achieving a consensus on this entity would mean to make the first step toward a targeted therapeutic strategy of intervention.

Predictive value of early EEG for seizures in neonates with hypoxic-ischemic encephalopathy undergoing therapeutic hypothermia

OBJECTIVES

To assess the prognostic significance of an early normal/mildly abnormal conventional EEG (cEEG) on seizure risk in neonates undergoing therapeutic hypothermia.

METHODS

We reviewed the video-EEG recordings from a large cohort of neonates treated with therapeutic hypothermia for hypoxic-ischemic encephalopathy from 2008 to 2017 in a single tertiary center. Continuous video-EEG was started as soon as possible (median 8.2 h) and continued throughout hypothermia and rewarming. We studied those neonates with a normal/mildly abnormal EEG during the first 24 h of monitoring.

RESULTS

A total of 331 neonates were treated with hypothermia and 323 had cEEG recordings available for review; 99 were excluded because of a moderately/severely abnormal cEEG background and/or seizure during the first 24 h of recording, and an additional eight because of early rewarming. The remaining 216 had a normal/mildly abnormal cEEG in the first 24 h. None of these patients subsequently developed seizures.

CONCLUSION

A normal/mildly abnormal cEEG during the first 24 h indicates a very low risk of subsequent seizures. This suggests that cEEG monitoring can be safely discontinued after 24 h if it has remained normal or excessively discontinuous and no seizures are detected, limiting the need for this resource-intensive and expensive tool.

Brain cooling reduces the risk of postneonatal epilepsy in newborns affected by moderate to severe hypoxic-ischemic encephalopathy

BACKGROUND

Neonatal hypoxic-ischemic encephalopathy is still a significant cause of neonatal death and neurodevelopmental disabilities, such as cerebral palsy, mental delay, and epilepsy. After the introduction of therapeutic hypothermia, the prognosis of hypoxic-ischemic encephalopathy has improved, with reduction of death and disabilities. However, few studies evaluated whether hypothermia affects rate and severity of postneonatal epilepsy. We evaluated rates, characteristics and prognostic markers of postneonatal epilepsy in infants with moderate to severe hypoxic-ischemic encephalopathy treated or not with therapeutic hypothermia.

METHODS

We analyzed clinical data, EEG recordings, cerebral Magnetic Resonance Imaging (MRI) and outcome in 23 cooled and 26 non-cooled asphyxiated neonates (≥36 weeks' gestation), admitted from 2004 to 2012.

RESULTS

Among 49 neonates 11 (22%) had postneonatal epilepsy, of which 9 (18%) were non-cooled and 2 (4%) were cooled (P=0.05). Six of 11 infants (55%) had West syndrome, 4 (36%) had focal epilepsy and 1 (9%) had Lennox-Gastaut Syndrome. At multiple logistic regression analysis MRI pattern significantly correlated with postneonatal epilepsy (OR 0.19, 95% CI 0.04-0.88, P=0.03). Extensive lesions in basal ganglia and thalami plus cortical and white matter were associated with postneonatal epilepsy.

CONCLUSIONS

Only perinatal asphyxia with extensive lesions in basal ganglia and thalami plus cortical and white matter lesion conveys a high risk for early and severe postneonatal epilepsy. Moreover, therapeutic hypothermia is associated with a decrease of the risk of developing postneonatal epilepsy.

Bazedoxifene and raloxifene protect neocortical neurons undergoing hypoxia via targeting ERα and PPAR-γ

Selective estrogen receptor modulators (SERMs) such as bazedoxifene and raloxifene are recognized to mainly act via estrogen receptors (ERs), but there is no study examining the involvement of PPAR-γ in their actions, especially in neurons undergoing hypoxia. Little is also known about age-dependent actions of the SERMs on neuronal tissue challenged with hypoxia. In this study, bazedoxifene and raloxifene protected neocortical cells against hypoxia at early and later developmental stages. Both SERMs evoked caspase-3-independent neuroprotection and increased protein levels of ERα (66 and 46 kDa isoforms) and PPAR-γ. In addition, bazedoxifene enhanced expression of ERα-regulated Cyp19a1 mRNA. Using double siRNA silencing, for the first time we demonstrated a key role of ERα and PPAR-γ in the neuroprotective action of the SERMs in neocortical neurons undergoing hypoxia. This study provides prospects for the development of a new therapeutic strategies against hypoxic brain injury that selectively target ERα and/or PPAR-γ.

Autophagy activation involved in hypoxic-ischemic brain injury induces cognitive and memory impairment in neonatal rats

Hypoxic-ischemic brain injury (HIBI) in neonates can lead to lifelong cognitive and memory impairment, but protective strategies are lacking at present. It has been demonstrated that autophagy plays a critical role in HIBI, while the function of autophagy in cognitive and memory impairment induced by HIBI in neonates has not been tested. In this study, we tested the impact of autophagy on the impairment of cognitive function and memory in HIBI neonatal rats by using a Morris water maze and investigated its possible mechanisms, which were established as HIBI model by ligating the left common carotid artery in neonatal rats, followed by 2-h hypoxia. The expression of microtubule-associated protein 1 light chain 3 (LC3)-II increased in HI group 24 h after HI in neonatal rats, while Sequestosome 1 (P62/SQSTM1), phosphorylated cAMP-response element-binding protein (p-CREB) decreased (compared with the sham group, p < 0.05), which were shown in the same left hippocampus CA3 region by immunofluorescence analysis. Brain injury of neonatal rats was aggravated significantly at 7 day after HI, coinciding with the results of Morris water maze. An autophagy inhibitor, 3-methyladenine (3-MA) pretreatment significantly attenuated the increase of LC3II and the loss of P62/SQSTM1 and p-CREB, ameliorated neuronal death, and improved the results of Morris water maze. Our results demonstrate that HIBI in neonatal rats induced excessive autophagy flux, which aggravated brain injury and induced cognitive and memory impairment during adolescence. Inhibition of autophagy reversed the results partly and improved the function of spatial learning and memory by attenuating the reduction of p-CREB. The use of autophagy modulators in the immature brain would create new opportunities for protective strategies clinically in the future.