Temporal Trends in the Severity and Mortality of Neonatal Hypoxic-Ischemic Encephalopathy in the Era of Hypothermia

Retrospective study on neonatal seizures in a tertiary center of northern Italy after ILAE classification: Incidence, seizure type, EEG and etiology

OBJECTIVE

We aimed to evaluate epidemiology, seizure type, EEG, and etiology of neonatal seizures (NS) in a tertiary neonatal intensive care unit.

METHODS

Data on infants with a neurophysiological confirmation of NS were collected between 2009 and 2022. Seizure types and epileptic syndromes were classified by the ILAE classification and EEG by the Italian Neonatal Seizure Collaborative Network (INNESCO) score.

RESULTS

Out of 91,253 neonates, 145 presented with NS; 69.7 % were born at term and 30.3 % were preterm infants. The incidence of NS in neonates born at our center was 1.2 per 1,000 live newborns (96/80697 neonates) while in the entire neonatal population admitted to our center it was 1.6 per 1,000 live births, increasing with lower preterm age. Compared to previous studies, we found a lower proportion of hypoxic-ischemic encephalopathy (HIE) (23.4 %) and a higher rate of genetic contribution (26.2 %). The infection rate was higher in preterm (31.8 %) than in full term (9.9 %) infants. Electrographic seizures were associated with acute provoked seizures (35.9 %), preterm age (52.3 %), and HIE (52.9 %). Vascular etiology was associated with focal clonic seizures (56.8 %). Non-structural neonatal genetic epilepsy was associated with sequential seizures (68.2 %), particularly KCNQ2 and SCN2A epilepsy. Background EEG was abnormal in all HIE, infections (85.7 %) and metabolic NS (83.3 %). In genetic epilepsy, background EEG depended on the epileptic syndrome: normal in 80 % of self-limited neonatal epilepsy and abnormal in 77.8 % of developmental and epileptic encephalopathy. Electroclinical seizures were associated with focal onset, while electrographic seizures correlated with a multifocal onset.

CONCLUSIONS

A low incidence of HIE and a high incidence of genetic etiology were observed in our cohort of NS. Seizure type and EEG features are fundamental to address etiology.

Magnesium sulfate and risk of hypoxic-ischemic encephalopathy in a high-risk cohort

BACKGROUND

Hypoxic-ischemic encephalopathy contributes to morbidity and mortality among neonates ≥36 weeks of gestation. Evidence of preventative antenatal treatment is limited. Magnesium sulfate has neuroprotective properties among preterm fetuses. Hypertensive disorders of pregnancy are a risk factor for hypoxic-ischemic encephalopathy, and magnesium sulfate is recommended for maternal seizure prophylaxis among patients with preeclampsia with severe features.

OBJECTIVE

(1) Determine trends in the incidence of hypertensive disorders of pregnancy, antenatal magnesium sulfate, and hypoxic-ischemic encephalopathy; (2) evaluate the association between hypertensive disorders of pregnancy and hypoxic-ischemic encephalopathy; and (3) evaluate if, among patients with hypertensive disorders of pregnancy, the odds of hypoxic-ischemic encephalopathy is mitigated by receipt of antenatal magnesium sulfate.

STUDY DESIGN

We analyzed a prospective cohort of live births ≥36 weeks of gestation between 2012 and 2018 within the California Perinatal Quality Care Collaborative registry, linked with the California Department of Health Care Access and Information files. We used Cochran-Armitage tests to assess trends in hypertensive disorders, encephalopathy diagnoses, and magnesium sulfate utilization and compared demographic factors between patients with or without hypertensive disorders of pregnancy or treatment with magnesium sulfate. Hierarchical logistic regression models were built to explore if hypertensive disorders of pregnancy were associated with any severity and moderate/severe hypoxic-ischemic encephalopathy. Separate hierarchical logistic regression models were built among those with hypertensive disorders of pregnancy to evaluate the association of magnesium sulfate with hypoxic-ischemic encephalopathy.

RESULTS

Among 44,314 unique infants, the diagnosis of hypoxic-ischemic encephalopathy, maternal hypertensive disorders of pregnancy, and the use of magnesium sulfate increased over time. Compared with patients with hypertensive disorders of pregnancy alone, patients with hypertensive disorders treated with magnesium sulfate represented a high-risk population. They were more likely to be publicly insured, born between 36 and 38 weeks of gestation, be small for gestational age, have lower Apgar scores, require a higher level of resuscitation at delivery, have prolonged rupture of membranes, experience preterm labor and fetal distress, and undergo operative delivery (all P<.002). Hypertensive disorders of pregnancy were associated with hypoxic-ischemic encephalopathy (adjusted odds ratio, 1.26 [95% confidence interval, 1.13-1.40]; P<.001) and specifically moderate/severe hypoxic-ischemic encephalopathy (adjusted odds ratio, 1.26 [95% confidence interval, 1.11-1.42]; P<.001). Among patients with hypertensive disorders of pregnancy, treatment with magnesium sulfate was associated with 29% reduction in the odds of neonatal hypoxic-ischemic encephalopathy (adjusted odds ratio, 0.71 [95% confidence interval, 0.52-0.97]; P=.03) and a 37% reduction in the odds of moderate/severe neonatal hypoxic-ischemic encephalopathy (adjusted odds ratio, 0.63 [95% confidence interval, 0.42-0.94]; P=.03).

CONCLUSION

Hypertensive disorders of pregnancy are associated with hypoxic-ischemic encephalopathy and, specifically, moderate/severe disease. Among people with hypertensive disorders, receipt of antenatal magnesium sulfate is associated with a significant reduction in the odds of hypoxic-ischemic encephalopathy and moderate/severe disease in a neonatal cohort admitted to neonatal intensive care unit at ≥36 weeks of gestation. The findings of this observational study cannot prove causality and are intended to generate hypotheses for future clinical trials on magnesium sulfate in term infants.

Incidence of encephalopathy and comorbidity in infants with perinatal asphyxia: a comparative prospective cohort study

Background

Programs that aim to improve the detection hypoxic-ischemic encephalopathy (HIE) should establish which neonates suffering from perinatal asphyxia need to be monitored within the first 6 h of life.

Method

An observational prospective cohort study of infants with gestational age ≥35 weeks, and above 1,800g, were included according to their arterial cord pH value (ApH): ≤7.00 vs. 7.01-7.10. Data was collected including obstetrical history, as well as neonatal comorbidities, including the presence of HIE, that happened within 6 h of life. A standardized neurological exam was performed at discharge.

Results

There were 9,537 births; 176 infants with ApH 7.01-7.10 and 117 infants with ApH ≤7.00. All 9 cases with moderate-to-severe HIE occurred among infants with ApH ≤7.00. The incidence of global and moderate-severe HIE was 3/1,000 and 1/1,000 births, respectively. Outcome at discharge (abnormal exam or death) showed an OR 12.03 (95% CI 1.53, 94.96) in infants with ApH ≤7.00 compared to ApH 7.01-7.10 cohort. Ventilation support was 5.1 times (95% CI 2.87, 9.03) more likely to be needed by those with cord ApH ≤7.00 compared to those with ApH 7.01-7.10, as well as hypoglycemia (37% vs. 25%; p = 0.026). In 55%, hypoglycemia occurred despite oral and/or intravenous glucose administration had been already initiated.

Conclusions

Cord pH 7.00 might be a safe pH cut-off point when developing protocols to monitor infants born with acidemia in order to identify infants with moderate or severe HIE early on. There is non-negligible comorbidity in the ApH ≤7.00 cohort, but also in the 7.01-7.10 cohort.

Growth and developmental outcomes of infants with hypoxic ischemic encephalopathy

Despite advances in obstetric care, hypoxic ischemic encephalopathy (HIE) remains a significant disease burden. We determined the national trends of HIE prevalence, therapeutic hypothermia (TH) use, mortality, and outcomes from 2012 to 2019. This study included term infants diagnosed with HIE between 2012 and 2019 from the National Health Insurance Service database. The prevalence of HIE was 2.4 per 1000 births without significant change during the period. TH was performed in approximately 6.7% of infants with HIE, and the annual variation ranged from 2.4 to 12.5%. The mortality among all term infants with HIE was 4.6%. The mortality rate among infants with HIE and TH significantly declined from 40 to 16.9% during the eight years. Infants with TH had higher mortality, increased use of inhaled nitric oxide, and more invasive ventilator use, indicating greater disease severity in the TH group. Infants with TH also showed significantly poorer outcomes, including delayed development, cerebral palsy, sensorineural hearing loss, and seizure, compared to infants without TH (p < 0.0001). With the increasing application of TH, mortality and developmental outcomes among infants with HIE have been improving in the past eight years in Korea. Further efforts to improve outcomes should be needed.

An observational, multicenter, registry-based cohort study of Turkish Neonatal Society in neonates with Hypoxic ischemic encephalopathy

BACKGROUND

Hypoxic ischemic encephalopathy (HIE) is a significant cause of mortality and short- and long-term morbidities. Therapeutic hypothermia (TH) has been shown to be the standard care for HIE of infants ≥36 weeks gestational age (GA), as it has been demonstrated to reduce the rates of mortality, and adverse neurodevelopmental outcomes. This study aims to determine the incidence of HIE in our country, to assess the TH management in infants with HIE, and present short-term outcomes of these infants.

METHODS

The Turkish Hypoxic Ischemic Encephalopathy Online Registry database was established for this multicenter, prospective, observational, nationally-based cohort study to evaluate the data of infants born at ≥34 weeks GA who displayed evidence of neonatal encephalopathy (NE) between March, 2020 and April 2022.

RESULTS

The incidence of HIE among infants born at ≥36 weeks GA (n = 965) was 2.13 per 1000 live births (517:242440), and accounting for 1.55% (965:62062) of all neonatal intensive care unit admissions. The rates of mild, moderate and severe HİE were 25.5% (n = 246), 58.9% (n = 568), and 15.6% (n = 151), respectively. Infants with severe HIE had higher rates of abnormal magnetic resonance imaging (MRI) findings, and mortality (p<0.001). No significant difference in mortality and abnormal MRI results was found according to the time of TH initiation (<3 h, 3-6 h and >6 h) (p>0.05). TH was administered to 85 (34.5%) infants with mild HIE, and of those born of 34-35 weeks of GA, 67.4% (n = 31) received TH. A total of 58 (6%) deaths were reported with a higher mortality rate in infants born at 34-35 weeks of GA (OR 3.941, 95% Cl 1.446-10.7422, p = 0.007).

CONCLUSION

The incidence of HIE remained similar over time with a reduction in mortality rate. The timing of TH initiation, whether <3 or 3-6 h, did not result in lower occurrences of brain lesions on MRI or mortality. An increasing number of infants with mild HIE and late preterm infants with HIE are receiving TH; however, the indications for TH require further clarification. Longer follow-up studies are necessary for this vulnerable population.

Perinatal Hypoxic-Ischemic Encephalopathy: Incidence Over Time Within a Modern US Birth Cohort

BACKGROUND

Recent studies suggest that the incidence of perinatal hypoxic-ischemic encephalopathy (HIE) may be increasing in developed countries. However, this observed increase may be due to increased ascertainment and increased treatment with therapeutic hypothermia rather than an increase in disease burden. In a US population-based cross-sectional study, we determined the incidence of perinatal HIE over time.

METHODS

The study population included all 289,793 live-born infants ≥35 weeks gestational age born at 15 Kaiser Permanente Northern California hospitals between 2012 and 2019. Perinatal HIE was defined as the presence of both neonatal acidosis (i.e., cord blood pH < 7 or base deficit ≥10, or base deficit ≥10 on first infant gas) and neonatal encephalopathy confirmed by medical record review. Hospital discharge diagnoses of HIE were determined by extracting International Classification of Disease diagnostic codes for HIE assigned upon hospital discharge.

RESULTS

The population incidence of perinatal HIE was 1.7 per 1000. Although the incidence of perinatal HIE did not change significantly, both hospital discharge diagnoses of HIE and treatment with therapeutic hypothermia increased significantly during the study period. The sensitivity and positive predictive value of a hospital discharge diagnosis of HIE for identifying perinatal HIE confirmed by chart review were 72% and 79%, respectively.

CONCLUSIONS

During the study years, the incidence of perinatal HIE remained stable despite increases in hospital discharge diagnoses of HIE and in the use of therapeutic hypothermia. Our findings underscore the importance of applying stringent diagnostic criteria when diagnosing this complex condition.

Value of brain injury-related indicators based on neural network in the diagnosis of neonatal hypoxic-ischemic encephalopathy

Neonatal hypoxic ischemic encephalopathy is a common disease, which is caused by fetal hypoxia, asphyxia, and other reasons. It may cause sequelae of the nervous system and even death in children. Computer tomography examination can clarify the scope and location of the disease and provide the basis for clinical treatment and prognosis. Relevant personnel analyzed the symptoms of ischemic hypoxia and found that ischemia and hypoxia were the main causes of encephalopathy. Neonatal ischemia and hypoxia are easy to cause serious damage. At present, with the development of medicine, the function of the human brain is the most important issue in natural science. The law of neural activity and the role of molecular cells, organs, and systems have fundamental construction significance for the prevention and treatment of nerve and mental diseases. By analyzing the value of the diagnosis of neonatal hypoxic-ischemic encephalopathy in the analysis of experimental data, by setting the newborns in the controlled group and the trial group as experimental subjects, this paper analyzed the situation of newborns in terms of body temperature, body weight, and respiratory rate, and used Apgar score to score these standards. It was found that the score of the controlled group was 7 and above, and the score of the trial group was below 7. It was found that the Apgar scoring method was more simple. Then, the newborns were analyzed by cord blood gas analysis. It was found that most of the data in the control group were between 7.8 and 8.4, and the data in the trial group were between 5.8 and 7.1. The umbilical blood gas analysis score of the experimental group was lower than that of the control group. By comparing the satisfaction of cord blood gas analysis and the Apgar score, it was found that the satisfaction of cord blood gas analysis was 24.06% higher than that of the Apgar score.

Correlation of Different MRI Scoring Systems with Long-Term Cognitive Outcome in Cooled Asphyxiated Newborns

(1) Background: Cerebral MRI plays a significant role in assessing the extent of brain injury in neonates with neonatal encephalopathy after perinatal asphyxia. Over the last decades, several MRI scoring systems were developed to enhance the predictive accuracy of MRI. The aim of this study was to validate the correlation of four established MRI scoring systems with cognitive long-term outcomes in cooled asphyxiated newborns. (2) Methods: Forty neonates with neonatal encephalopathy treated with therapeutic hypothermia were included in this retrospective study. The MRI scans from the second week of life were scored using four existing MRI scoring systems (Barkovich, NICHD, Rutherford, and Weeke). The patients' outcome was assessed with the Bayley Scales of Infant Development (BSID-III) at the age of 2 years. To evaluate the correlation between the MRI scoring system with the cognitive scores of BSID-III, the correlation coefficient was calculated for each scoring system. (3) Results: All four MRI scoring systems showed a significant correlation with the cognitive scores of BSID-III. The strongest correlation was found between the Weeke Score (r2 = 0.43), followed by the Rutherford score (r2 = 0.39), the NICHD score (r2 = 0.22), and the Barkovich score (r2 = 0.17). (4) Conclusion: Our study confirms previously published results in an independent cohort and indicates that the Weeke and Rutherford scores have the strongest correlation with the cognitive score of BSID-III in cooled asphyxiated newborns.

End-of-life care over four decades in a quaternary neonatal intensive care unit

AIM

Death in the neonatal intensive care unit (NICU) commonly follows a decision to withdraw or limit life-sustaining treatment. Advances in medicine have changed the nature of life-sustaining interventions available and the potential prognosis for many newborn conditions. We aimed to assess changes in causes of death and end-of-life care over nearly four decades.

METHODS

A retrospective review of infants dying in the NICU was performed (2017-2020) and compared with previous audits performed in the same centre (1985-1987 and 1999-2001). Diagnoses at death were recorded for each infant as well as their apparent prognosis and any withdrawal or limitations of medical treatment.

RESULTS

In the recent epoch, there were 88 deaths out of 2084 admissions (4.2%), a reduction from the previous epochs (132/1362 (9.7%) and 111/1776 (6.2%), respectively, for epochs 1 and 2). More than 90% of infants died after withdrawal of life-sustaining treatment, an increase from the previous two epochs (75%). There was a reduction in deaths from chromosomal abnormalities, complications related to prematurity and severe birth asphyxia.

CONCLUSIONS

There continue to be changes in both the diagnoses leading to death and approaches to withdrawal of treatment in the NICU. These may reflect ongoing changes in both prenatal and post-natal diagnostics as well as changing attitudes towards palliative care within the medical and wider community.

3D doppler ultrasound imaging of cerebral blood flow for assessment of neonatal hypoxic-ischemic brain injury in mice

Cerebral blood flow (CBF) acutely reduces in neonatal hypoxic-ischemic encephalopathy (HIE). Clinic studies have reported that severe CBF impairment can predict HIE outcomes in neonates. Herein, the present study uses a non-invasive 3D ultrasound imaging approach to evaluate the changes of CBF after HI insult, and explores the correlation between CBF alterations and HI-induced brain infarct in mouse pups. The neonatal HI brain injury was induced in postnatal day 7 mouse pups using the Rice-Vannucci model. Non-invasive 3D ultrasound imaging was conducted to image CBF changes with multiple frequencies on mouse pups before common carotid artery (CCA) ligation, immediately after ligation, and 0 or 24 hours after HI. Vascularity ratio of the ipsilateral hemisphere was acutely reduced after unilateral ligation of the CCA alone or in combination with hypoxia, and partially restored at 24 hours after HI. Moreover, regression analysis showed that the vascularity ratio of ipsilateral hemisphere was moderately correlated with brain infarct size 24 hours after HI, indicating that CBF reduction contributes to of HI brain injury. To further verify the association between CBF and HI-induced brain injury, a neuropeptide C-type natriuretic peptide (CNP) or PBS was intranasally administrated to the brain of mouse pups one hour after HI insult. Brain infarction, CBF imaging and long-term neurobehavioral tests were conducted. The result showed that intranasal administration of CNP preserved ipsilateral CBF, reduced the infarct size, and improved neurological function after HI brain injury. Our findings suggest that CBF alteration is an indicator for neonatal HI brain injury, and 3D ultrasound imaging is a useful non-invasive approach for assessment of HI brain injury in mouse model.

Trends of neonatal hypoxic-ischemic encephalopathy prevalence and associated risk factors in the United States, 2010 to 2018

BACKGROUND

Despite recent advances in perinatal care, neonatal hypoxic-ischemic encephalopathy remains one of the most common causes of neonatal morbidity and mortality. The trends for prevalence and mortality of neonatal hypoxic-ischemic encephalopathy have not been examined in the era of therapeutic hypothermia in the United States.

OBJECTIVE

This study aimed to determine (1) the overall and gestational age-specific (35-36, ≥37, and >42 weeks) trends of hypoxic-ischemic encephalopathy prevalence and use of therapeutic hypothermia, (2) the trends of mortality in association with hypoxic-ischemic encephalopathy, (3) the confounding variables associated with hypoxic-ischemic encephalopathy, and (4) the clinical outcomes of neonates with hypoxic-ischemic encephalopathy.

STUDY DESIGN

This study used National Inpatient Sample datasets from 2010 to 2018. Moreover, the study included infants with a gestational age of ≥35 weeks with a documented hypoxic-ischemic encephalopathy diagnosis (mild, moderate, severe, or unspecified). We calculated trends in hypoxic-ischemic encephalopathy prevalence and the use of therapeutic hypothermia using chi-squared testing. Furthermore, this study used logistic regression models to control for confounders.

RESULTS

A total of 32,180,617 infants were included, of which 31,249,100 were term (gestational age of ≥37 weeks) and 931,517 were late preterm (gestational age of 35-36 weeks). Hypoxic-ischemic encephalopathy prevalence slightly increased from 0.093% in 2010-2012 to 0.097% in 2016-2018 (P=.01) in term infants and did not significantly change in late preterm infants (P=.20). There were 6235 term infants (20.8%) and 449 late preterm infants (21.1%) with hypoxic-ischemic encephalopathy who were managed with therapeutic hypothermia. The use of therapeutic hypothermia in both term and late preterm infants has increased over the years (P<.01). The mortality rate with hypoxic-ischemic encephalopathy decreased over time from 11.5% to 12.3% between 2010 to 2012, and from 8.3% to 10.6% betweenn 2016 to 2018 (P<.01). The factors with the strongest association with hypoxic-ischemic encephalopathy were placental infarction or insufficiency (odds ratio, 144; 95% confidence interval, 134-157), placental abruption (odds ratio, 101; 95% confidence interval, 91-112), cord prolapse (odds ratio, 74; 95% confidence interval, 65-84), and maternal anemia (odds ratio, 26; 95% confidence interval, 20-37).

CONCLUSION

Hypoxic-ischemic encephalopathy prevalence in neonates essentially remained the same at 1 per 1000 live births. The use of therapeutic hypothermia increased, and the mortality rate decreased in infants with hypoxic-ischemic encephalopathy. The identification of hypoxic-ischemic encephalopathy-associated factors should promote increased vigilance to optimize newborn outcomes.

Research advances in the role of endogenous neurogenesis on neonatal hypoxic-ischemic brain damage

Hypoxic-ischemic brain damage (HIBD) is the main cause of perinatal mortality and neurologic complications in neonates, but it remains difficult to cure due to scarce treatments and complex molecular mechanisms remaining incompletely explained. Recent, mounting evidence shows that endogenous neurogenesis can improve neonatal neurological dysfunction post-HIBD. However, the capacity for spontaneous endogenous neurogenesis is limited and insufficient for replacing neurons lost to brain damage. Therefore, it is of great clinical value and social significance to seek therapeutic techniques that promote endogenous neurogenesis, to reduce neonatal neurological dysfunction from HIBD. This review summarizes the known neuroprotective effects of, and treatments targeting, endogenous neurogenesis following neonatal HIBD, to provide available targets and directions and a theoretical basis for the treatment of neonatal neurological dysfunction from HIBD.