Does amplitude-integrated electroencephalogram background pattern correlate with cerebral injury in neonates with hypoxic-ischaemic encephalopathy?

How do we reach the goal of personalized medicine for neuroprotection in neonatal hypoxic-ischemic encephalopathy?

Therapeutic hypothermia is now standard of care for neonates with hypoxic-ischemic encephalopathy (HIE) in high income countries (HIC). Conversely, compelling trial evidence suggests that hypothermia is ineffective, and may be deleterious, in low- and middle-income countries (LMIC), likely reflecting the lower proportion of infants who had sentinel events at birth, suggesting that injury had advanced to a stage when hypothermia is no longer effective. Although hypothermia significantly reduced the risk of death and disability in HICs, many infants survived with disability and in principle may benefit from targeted add-on neuroprotective or neurorestorative therapies. The present review will assess biomarkers that could be used to personalize treatment for babies with HIE - to determine first whether an individual infant is likely to respond to hypothermia, and second, whether additional treatments may be beneficial.

Fully automated simultaneous peripheral arteriovenous exchange transfusion not seen to aggravate brain function and the disorder of the internal environment in neonates with severe hyperbilirubinemia

BACKGROUND

The acute changes in brain function in newborn infants undergoing ET remain unclear. This study aimed to determine whether fully automated simultaneous peripheral arteriovenous ET would influence the brain function.

METHODS

A retrospective analysis was conducted on the clinical data of 39 neonates with hyperbilirubinemia who received ET. Seventeen patients were in the encephalopathy group, and the other 22 patients were in the non-encephalopathy group. Changes in amplitude-integrated electroencephalogram (aEEG) during ETs were analyzed, including background activities, sleep-wake cycling (SWC), and seizures. Before and after the ET, routine blood test parameters, electrolytes, blood glucose, and blood gas parameters were measured.

RESULTS

After ETs, there were no significant changes in the levels of pH, PaO₂, PaCO₂, lactate, and red blood cells, while the levels of total bilirubin, indirect bilirubin, blood potassium, blood sodium, serum calcium, while blood cells, and platelets were significantly lower and the level of blood glucose was significantly higher compared to those before therapy. There was no significant difference in the changes of electroencephalographic activities during ETs, including background activities, SWC, and seizures. However, there were significant differences in suppressions on background activities, while there were no significant statistical differences in SWC or seizures between the 2 groups.

CONCLUSION

Fully automated simultaneous peripheral arteriovenous ET is safe and efficient without significant influence on the disorder of the internal environment and electroencephalographic activities after ET in neonates. However, background activities are more significantly depressed in infants of bilirubin encephalopathy than infants of non-encephalopathy during ET.

Clinical, Neuroimaging, and Electrographic Predictors of Phenobarbital Failure in Newborns With Hypoxic Ischemic Encephalopathy and Seizures

BACKGROUND

Many neonates with hypoxic ischemic encephalopathy and seizures do not respond to the first line antiepileptic drug, phenobarbital. Little is known about what factors are associated with its failure.

OBJECTIVE

To examine factors associated with failure of phenobarbital therapy in neonates with hypoxic ischemic encephalopathy and seizures.

DESIGN/METHODS

A single-center retrospective review of 50 term (>35 weeks) neonates with hypoxic ischemic encephalopathy and seizures treated with phenobarbital as the first-line antiepileptic. Neonates were classified into either responders (n = 30) or nonresponders (n = 20). Nonresponse was defined as continued seizures after maximum dosing of phenobarbital or an additional antiepileptic. Subjects with acceptable magnetic resonance imaging (MRI) scans obtained within 2 weeks of birth were included in the study and rated using an MRI injury scoring system. Charts were reviewed for demographic, clinical, and laboratory variables. Resuscitation and seizure scores were also calculated. Electroencephalographic (EEG) background activity was reviewed in 2 different time epochs (12-24 hours and 24-36 hours of life) and graded as per ACNS guidelines.

RESULTS

There were no significant group differences in demographic, clinical, and laboratory variables except nonresponders, who had higher mean seizure score (P = .01) and significantly more injury on MRI scan for white matter (P = .004), parenchymal cortex (P = .027), and watershed (P = .009) regions. Neonates with moderately abnormal or severely abnormal background EEG responded poorly to phenobarbital.

CONCLUSION

In the presence of above factors, one can anticipate that additional antiepileptic medication may be needed. These data also support that larger studies should be done to look prospectively at using alternative agents first line in patients with severe injury.

Association of cerebral activity with MRI scans in infants with neonatal encephalopathy undergoing therapeutic hypothermia

We aimed to correlate amplitude-integrated EEG (aEEG) in neonatal hypoxic ischemic encephalopathy (HIE) with early magnetic resonance imaging (MRI). In this retrospective study, 32 neonates over 35 weeks' gestation with moderate/severe HIE who were treated with hypothermia were included. Early MRI scans and daily aEEG background were categorized to mild/normal, moderate, and severely abnormal. Time to sleep cycling was noted on aEEG. Mantel-Haenszel test for trends was used to explore associations between aEEG and MRI and outcome. LOESS regression was used for exploring the association of cycling with MRI scores. MRI was normal/mildly abnormal in 20 (63%) infants; in 9 (28%), moderately abnormal; and in 3 (9%), severely abnormal. Twenty-seven (84%) infants s urvived. MRI severity score was significantly associated with aEEG background score on the third and fourth days of life (p < 0.01). An increase in the MRI severity score was noted if sleep cycling appeared after the fifth day of life.Conclusions: Depressed aEEG at the third and fourth days of life and appearance of cycling beyond the fifth day of life are associated with cerebral MRI abnormalities and may be associated with increased risk of abnormal outcome. What is known: • Since therapeutic hypothermia has been shown to change long-term outcome, amplitude-integrated EEG in infants with hypoxic ischemic neonatal encephalopathy soon after birth have a limited predictive power for long-term outcome in treated infants. • Brain MRI after therapeutic hypothermia in the above infants has a significant predictive value for long-term outcome What is new: • Background amplitude-integrated EEG activity depression at the age of 3 and 4 days and delay of appearance of cycling activity are associated with worse MRI scores and may be predictive of worse long-term outcome.

Prognostic Value of Electroencephalography in Hypothermia-Treated Neonates With Hypoxic-Ischemic Encephalopathy: A Meta-Analysis

BACKGROUND

Electroencephalography (EEG) background activity is associated with neurological outcome in neonates with hypoxic-ischemic encephalopathy. There is uncertainty about the prognostic value of EEG background activity after hypothermia was introduced.

METHODS

Searches were made on Pubmed, Embase, and the Cochrane Library, from inception to March 1, 2018. Pooled sensitivities and specificities were calculated to assess the diagnostic power of burst suppression, low voltage, and flat trace background activities in the prediction of an adverse neurological outcome in the follow-up period in hypothermia-treated neonates with hypoxic-ischemic encephalopathy. I² was used to assess heterogeneity, and meta-regression was done to explore the source of heterogeneity.

RESULTS

Eighteen studies with 940 neonates were included. Pooled sensitivities and specificities in predicting the combination of death and neurodevelopmental impairment were burst suppression (sensitivity 0.87 [95% confidence interval (CI) 0.79 to 0.93], specificity 0.60 [95% CI 0.44 to 0.74]), low voltage (sensitivity 0.84 [0.75 to 0.90], specificity 0.80 [0.58 to 0.92]), and flat trace (sensitivity 0.85 [0.75 to 0.92], specificity 0.94 [0.77 to 0.99]). Subgroup analysis revealed the sensitivities of background patterns obtained after 24 hours of life were higher than those within age 24 hours, whereas the specificities were just the reverse. Flat trace performed best on sensitivity 0.93 (0.60 to 0.99) and specificity 0.90 (0.64 to 0.98) in predicting death. Burst suppression demonstrated the highest sensitivity 0.87 (0.58 to 0.97) and flat trace performed best on specificity 0.85 (0.60 to 0.96) in predicting neurodevelopmental impairment.

CONCLUSIONS

EEG background activity is predictive of long-term neurological outcome in hypothermia-treated neonates with hypoxic-ischemic encephalopathy. Burst suppression, low voltage, and flat trace are potential predictors of death or neurodevelopmental impairment.

Electroencephalography and brain magnetic resonance imaging in asphyxia comparing cooled and non-cooled infants

OBJECTIVE

The aim was to establish any differences in the predictive value of EEG and MRI for outcome in infants treated and not-treated with therapeutic hypothermia (HT) for perinatal asphyxia. We hypothesize that they are equally predictive and that combining both has the highest predictive value.

STUDY DESIGN

We retrospectively compared data of infants with hypoxic-ischemic encephalopathy (HIE) who received HT (n = 45) between September 2009 and December 2013 with those of infants with HIE born between January 2004 and August 2009, before HT was available (NT, n = 37). All received conventional and/or amplitude-integrated EEG during the first days and early MRI (day 4-5). Associations of EEG, MRI and severe neurodevelopmental outcome (death or Bayley's -2SD below mean), were tested with a multivariable logistic regression analysis, corrected for HT.

RESULTS

Forty-eight hours' EEG background pattern had a PPV of 92% and a NPV of 81% in HT, versus 100% and 58% in NT. MRI had a PPV of 71% and a NPV of 93% in HT, versus 82% and 75% in NT. The adjusted OR for adverse outcome was 0.013 (95% CI 0.002-0.154, p < 0.001) for EEG background normalization within 48 h and 32.19 (95% CI 4.84-214.25, p < 0.001) for abnormal MRI.

CONCLUSION

The predictive value of EEG and MRI is equal in cooled and non-cooled infants with HIE. Our data show a higher predictive value (death and severe outcome) for EEG compared to MRI. In HIE, persistent abnormal EEG background pattern until 48 h, combined with abnormal early MRI is strongly predictive for poor neurodevelopment.

Early Amplitude-Integrated Electroencephalogram as a Predictor of Brain Injury in Newborns With Very Low Birth Weight: A Cohort Study

PURPOSE

To evaluate the relationship between abnormal early amplitude integrated electroencephalography (EEG) and severe lesions in imaging tests performed during the neonatal period in very low birth weight infants.

METHODS

An amplitude-integrated EEG was performed in 70 patients with a mean birth weight of 1226 g during the first 48 hours of life. Severe lesions on magnetic resonance imaging (MRI) or ultrasonography (US) during the neonatal period were considered as adverse conditions. Variables were compared using the χ² test or analysis of variance. Sensitivity, specificity, and positive likelihood ratio were calculated.

RESULTS

Adverse outcomes were observed in 6 patients. There was a significant relationship ( P < .001) between abnormal amplitude-integrated EEG background and severe lesions on MRI and US. Sensitivity and specificity were 100% and 89%, respectively.

CONCLUSION

Early amplitude-integrated EEG with moderate/severe abnormalities in the background is associated with severe structural lesions detected in imaging studies and should be considered as an auxiliary screening tool for the detection of neonatal brain lesions in very low birth weight infants.

Benefits of starting hypothermia treatment within 6 h vs. 6-12 h in newborns with moderate neonatal hypoxic-ischemic encephalopathy

BACKGROUND

It has been suggested that mild hypothermia treatment of hypoxia-ischemic encephalopathy (HIE) should start within 6 h after HIE, but many children are admitted to the hospital > 6 h, particularly in developing areas. We aimed to determine whether hypothermia treatment could remain effective within 12 h after birth.

METHODS

According to their admission, 152 newborns were enrolled in the < 6 h and 6-12 h after HIE groups. All newborns received conventional treatment combined with mild head hypothermia therapy, according to our routine clinical practice. Some newborns only received conventional treatment (lacking informed consent). All newborns received amplitude-integrated electroencephalography (aEEG) monitoring for 4 h and neuron-specific enolase (NSE) measurement before and after 3 days of therapy.

RESULTS

Compared to the conventional treatment, hypothermia significantly improved the aEEG scores and NSE values in all newborns of the < 6-h group. In the 6-12-h group, the aEEG scores (F = 5.67, P < 0.05) and NSE values (F = 4.98, P < 0.05) were only improved in newborns with moderate HIE. Hypothermia treatment seems to have no effect in newborns with severe HIE after 6 h (P > 0.05). Hypothermia improved the rates of neonatal death and 18-month disability (all P < 0.01).

CONCLUSIONS

In newborns with moderate HIE, starting hypothermia therapy < 6 h and 6-12 h after HIE showed curative effects. In those with severe HIE, only starting hypothermia therapy within 6 h showed curative effects.

Predictive value of amplitude-integrated EEG (aEEG) after rescue hypothermic neuroprotection for hypoxic ischemic encephalopathy: a meta-analysis

OBJECTIVE

Amplitude-integrated electroencephalography (aEEG) is a useful bedside tool in predicting the neurodevelopmental outcome after neonatal encephalopathy; however, the prognostic accuracy may be altered by rescue hypothermic neuroprotection. The objective of this study is to examine the prognostic accuracy of aEEG for predicting long-term neurodevelopmental outcomes in term newborn infants undergoing therapeutic hypothermia for neonatal encephalopathy.

STUDY DESIGN

We examined all studies (Medline, Cumulative Index to Nursing and Allied Health Literature and the Cochrane Library; 2000 to 2014) comparing aEEG (6, 24, 48 or 72 h) in term encephalopathic babies undergoing therapeutic hypothermia, with neurodevelopmental outcome at 1 year or more. We extracted individual patient data from the eligible studies to calculate prognostic indices with exact confidence intervals (CIs). We considered continuous normal voltage as normal aEEG pattern and discontinuous normal voltage, burst suppression, flat trace and persistently low voltage as abnormal, and defined adverse outcome as death or moderate/severe disability at 1 year.

RESULTS

We reviewed a total of 70 articles, 17 of which met the inclusion criteria. Eight studies were excluded and 9 studies (N=520) were included in the meta-analysis. The pooled sensitivity and specificity for an abnormal trace at 6 h of age to predict adverse outcome were 96% (95% CI 91 to 98%) and 39% (95% CI 32 to 46%). The diagnostic odds ratio of an abnormal trace was highest at 48 h (66.9 (95% CI 19.7, 227.2)).

CONCLUSIONS

A persistantly abnormal aEEG at 48 h or more is associated with an adverse neurodevelopmal outcome. The positive prognostic value of 6 h aEEG is poor and good outcome may occur despite abnormal aEEG. Conversely, a normal 6 h aEEG has a good negative predictive value although do not exclude adverse outcomes.

ERP evidence of preserved early memory function in term infants with neonatal encephalopathy following therapeutic hypothermia

BACKGROUND

Neonatal encephalopathy (NE) carries high risk for neurodevelopmental impairments. Therapeutic hypothermia (TH) reduces this risk, particularly for moderate encephalopathy (ME). Nevertheless, these infants often have subtle functional deficits, including abnormal memory function. Detection of deficits at the earliest possible time-point would allow for intervention during a period of maximal brain plasticity.

METHODS

Recognition memory function in 22 infants with NE treated with TH was compared to 23 healthy controls using event-related potentials (ERPs) at 2 wk of age. ERPs were recorded to mother's voice alternating with a stranger's voice to assess attentional responses (P2), novelty detection (slow wave), and discrimination between familiar and novel (difference wave). Development was tested at 12 mo using the Bayley Scales of Infant Development, Third Edition (BSID-III).

RESULTS

The NE group showed similar ERP components and BSID-III scores to controls. However, infants with NE showed discrimination at midline leads (P = 0.01), whereas controls showed discrimination in the left hemisphere (P = 0.05). Normal MRI (P = 0.05) and seizure-free electroencephalogram (EEG) (P = 0.04) correlated positively with outcomes.

CONCLUSION

Infants with NE have preserved recognition memory function after TH. The spatially different recognition memory processing after early brain injury may represent compensatory changes in the brain circuitry and reflect a benefit of TH.

Postoperative Amplitude-Integrated Electroencephalography Predicts Four-Year Neurodevelopmental Outcome in Children with Complex Congenital Heart Disease

OBJECTIVES

To evaluate the predictive value of pre- and postoperative amplitude-integrated electroencephalography (aEEG) on neurodevelopmental outcomes in children operated for congenital heart disease (CHD).

STUDY DESIGN

Prospectively enrolled cohort of 60 infants with CHD who underwent cardiac surgery with cardiopulmonary bypass in the first 3 months of life. Infants with a genetic comorbidity were excluded. aEEG was assessed for 12 hours pre- and 48 hours postoperatively. Background pattern was classified by the use of standard categories, and the presence of seizures and sleep-wake cycles (SWCs) was noted. Outcome at 1 and 4 years of age was assessed with standardized developmental tests.

RESULTS

Preoperatively, infants either showed continuous normal voltage (n = 56) or discontinuous normal voltage (n = 4). Postoperatively, abnormal background pattern (flat trace, burst suppression, or continuous low voltage) was detected in 7 (12%), discontinuous normal voltage in 37 (61%), and continuous normal voltage in 16 (27%) infants. Nineteen infants (32%) did not return to normal SWCs within the recording period. Seizures were detected in 4 infants preoperatively and in another 4 postoperatively. After we controlled for surgical and postoperative risk factors, abnormal postoperative background pattern and lack of return to SWCs independently predicted poorer intelligence quotient at 4 years (P = .03 and P = .04 respectively) but was not related to motor outcome.

CONCLUSION

aEEG is a useful bedside tool that helps to predict outcome in infants undergoing open-heart surgery for CHD. Abnormal postoperative background pattern and lack of return to SWCs are markers for subsequent impaired cognitive development.

Sleep-wake cycle on amplitude-integrated EEG and neuroimage outcomes in newborns

BACKGROUND

The aim of this study was to evaluate the results of sleep-wake cycle monitoring using amplitude-integrated EEG (aEEG) and neuroimaging in newborn infants with a possible perinatal hypoxic insult, investigate the correlation between the findings, and determine the relevance of the findings to reasonably predict neurological outcome.

METHODS

aEEG was recorded among newborn infants suspected of perinatal asphyxia between November, 2014 and June, 2015 in one neonatal intensive care unit facility. Brain imaging with serial ultrasonography and MRI when available were performed, and the infants were divided into two groups according to findings and potential neurological outcome: Group I (favorable findings) and Group II (severe findings such as high grade intraventricular hemorrhage, cerebral infarction or white matter injury). Established sleep-wake cycle times after birth was compared between the two groups.

RESULTS

Among 107 newborn infants, 85 subjects were classified as Group I and the remaining 22 subjects as Group II. The total number of aEEG sessions was 207 and recording time was 2,796 h with a mean of 14.43 ± 13.40 h per study. Estimated times of cyclicity were earlier in Group I (113.34 h, 95 % CI 82.31-144.37) as compared to Group II (504.39 h, 95 % CI 319.91-688.88; p < 0.001).

CONCLUSIONS

Delayed cyclicity on aEEG has a strong correlation with unfavorable brain neuroimages in newborns with possible perinatal asphyxia. If sleep-wake cycles do not appear during initial period after birth, follow-up aEEG studies are recommended.

TRIAL REGISTRATION

Retrospectively registered Registration number: BD 2015-148 Name of registry: amplitude integrated EEG in neonate Date of registration: September 9, 2015.