Adherence to hypothermia guidelines: a French multicenter study of fullterm neonates

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.

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.

Glycemia and Neonatal Encephalopathy: Outcomes in the LyTONEPAL (Long-Term Outcome of Neonatal Hypoxic EncePhALopathy in the Era of Neuroprotective Treatment With Hypothermia) Cohort

OBJECTIVES

To assess in newborns with neonatal encephalopathy (NE), presumptively related to a peripartum hypoxic-ischemic event, the frequency of dysglycemia and its association with neonatal adverse outcomes.

STUDY DESIGN

We conducted a secondary analysis of LyTONEPAL (Long-Term Outcome of Neonatal hypoxic EncePhALopathy in the era of neuroprotective treatment with hypothermia), a population-based cohort study including 545 patients with moderate-to-severe NE. Newborns were categorized by the glycemia values assessed by routine clinical care during the first 3 days of life: normoglycemic (all glycemia measurements ranged from 2.2 to 8.3 mmol/L), hyperglycemic (at least 1 measurement >8.3 mmol/L), hypoglycemic (at least 1 measurement <2.2 mmol/L), or with glycemic lability (measurements included at least 1 episode of hypoglycemia and 1 episode of hyperglycemia). The primary adverse outcome was a composite outcome defined by death and/or brain lesions on magnetic resonance imaging, regardless of severity or location.

RESULTS

In total, 199 newborns were categorized as normoglycemic (36.5%), 74 hypoglycemic (13.6%), 213 hyperglycemic (39.1%), and 59 (10.8%) with glycemic lability, based on the 2593 glycemia measurements collected. The primary adverse outcome was observed in 77 (45.8%) normoglycemic newborns, 37 (59.7%) with hypoglycemia, 137 (67.5%) with hyperglycemia, and 40 (70.2%) with glycemic lability (P < .01). With the normoglycemic group as the reference, the aORs and 95% 95% CIs for the adverse outcome were significantly greater for the group with hyperglycemia (aOR 1.81; 95% CI 1.06-3.11).

CONCLUSIONS

Dysglycemia affects nearly two-thirds of newborns with NE and is independently associated with a greater risk of mortality and/or brain lesions on magnetic resonance imaging.

TRIAL REGISTRATION

NCT02676063.

Healthcare organizational factors associated with delayed therapeutic hypothermia in neonatal hypoxic-ischemic encephalopathy: the LyTONEPAL cohort

Initiation of therapeutic hypothermia (TH) within 6 h of life is a major concern for treating neonatal hypoxic ischemic encephalopathy (HIE). We aimed to determine clinical and healthcare organizational factors associated with delayed TH in a French population-based cohort of neonates with moderate/severe HIE. Time to reach a rectal temperature of 34 °C defines optimal and delayed (within and over 6 h, respectively) TH. Clinical and healthcare organizational factors associated with delayed TH were analysed among neonates born in cooling centres (CCs) and non-cooling centres (non-CCs). Among 629 neonates eligible for TH, 574 received treatment (91.3%). TH was delayed in 29.8% neonates and in 20.3% and 36.2% of those born in CCs and non-CCs, respectively. Neonates with moderate HIE were more exposed to delayed TH in both CCs and non-CCs. After adjustment for HIE severity, maternal and neonatal characteristics and circumstances of birth were not associated with increased risk of delayed TH. However, this risk was 2 to 5 times higher in maternities with < 1999 annual births, when the delay between birth and call for transfer (adjusted odds ratio [aOR] 2.47, 95% confidence interval [CI] [1.03 to 5.96]) or between call for transfer and admission (aOR 6.06, 95%CI [2.60 to 14.12]) was > 3 h and when an undesirable event occurred during transfer (aOR 2.66, 95%CI [1.11 to 6.37].  Conclusion: Increasing early identification of neonates who could benefit from TH and access to TH in non-CCs before transfer are modifiable factors that could improve care of neonates with HIE.  Trial registration: The trial was registered at ClinicalTrials.gov (NCT02676063). What is Known: • International recommendations are to initiate therapeutic hypothermia before 6 h of life in neonates with moderate or severe hypoxic ischemic encephalopathy. What is New: •In this French population-based cohort of infants with hypoxic ischemic encephalopathy, nearly one-third of neonates eligible for treatment did not have access to hypothermia in the therapeutic window of 6 h of life. . • Among infants born in non-cooling centres, healthcare organizational factors involved in delayed care were the small size of maternities (1999 annual births), a time interval of more than 3 h between birth and call for transfer and between call for transfer and admission in neonatology, and the occurrence of an undesirable event during transfer.

Adequacy of sedation analgesia to support the comfort of neonates undergoing therapeutic hypothermia and its impact on short-term neonatal outcomes

Objectives

We aimed to evaluate (1) whether sedation analgesia (SA) used during therapeutic hypothermia (TH) was efficient to support the wellbeing of neonates with hypoxic-ischemic encephalopathy, (2) the SA level and its adjustment to clinical pain scores, and (3) the impact of inadequate SA on short-term neonatal outcomes evaluated at discharge.

Methods

This was an observational retrospective study performed between 2011 and 2018 in two level III centers in Alsace, France. We analyzed the wellbeing of infants by using the COMFORT-Behavior (COMFORT-B) clinical score and SA level during TH, according to which we classified infants into four groups: those with excess SA, adequate SA, lack of SA, and variability of SA. We analyzed the variations in doses of SA and their justification. We also determined the impact of inadequate SA on neonatal outcomes at discharge by multivariate analyses with multinomial regression, with adequate SA as the reference.

Results

A total of 110 patients were included, 89 from Strasbourg university hospital and 21 from Mulhouse hospital. The COMFORT-B score was assessed 95.5% of the time. Lack of SA was mainly found on the first day of TH (15/110, 14%). In all, 62 of 110 (57%) infants were in excess of SA over the entire duration of TH. Most dose variations were related to clinical pain scores. Inadequate SA was associated with negative short-term consequences. Infants with excess of SA had a longer duration of mechanical ventilation [mean ratio 1.46, 95% confidence interval (CI), 1.13-1.89, p = 0.005] and higher incidence of abnormal neurological examination at discharge (odds ratio 2.61, 95% CI, 1.10-6.18, p = 0.029) than infants with adequate SA.

Discussion

Adequate SA was not easy to achieve during TH. Close and regular monitoring of SA level may help achieve adequate SA. Excess of SA can be harmful for newborns with hypoxic-ischemic encephalopathy who are undergoing TH.

Adherence to hypothermia guidelines in newborns with hypoxic-ischemic encephalopathy

INTRODUCTION

We do not have population data in Spain on the application of therapeutic hypothermia (TH). The objective was to examine adherence to management standards during TH of infants with hypoxic-ischemic encephalopathy (HIE).

METHOD

Multicenter observational cohort study from the beginning of TH (year 2010) in 5 hospitals in a Spanish region, until year 2019.

RESULTS

133 patients were recruited, 72% diagnosed with moderate HIE and the rest of them with severe HIE. In 84% of infants, passive hypothermia was started at birth. Active TH was started at a median age of 5 h of life (IQR 3.3; 6.3), although the central targeted temperature (33-34 °C) was reached at a median age of 3.5 h (IQR 1; 6). Those born extramural, initiated active TH 3.3 h on average later than those born intramural, but without differences in the age at which the targeted temperature was reached. Sedoanalgesia was used in 97%. 100% were monitored with amplitude-integrated EEG and 59% with cerebral oxymetry. MRI was performed in 94% with moderate HIE vs. 65% with severe; P < .001. Neuron-specific enolase in cerebrospinal fluid was determined in 42%. The average duration of rewarming was median 10 h (IQR 8; 12), with no differences depending on the degree of HIE (P = .57).

CONCLUSIONS

The implementation of TH successfully met the standards. However, aspects of care that could be improved were detected. Auditing newborn care with HIE is crucial to achieving programs with a high quality of care in each region.

Utilization of Therapeutic Hypothermia and Neurological Injury in Neonates with Mild Hypoxic-Ischemic Encephalopathy: A Report from Children's Hospital Neonatal Consortium

OBJECTIVE

This study was aimed to describe utilization of therapeutic hypothermia (TH) in neonates presenting with mild hypoxic-ischemic encephalopathy (HIE) and associated neurological injury on magnetic resonance imaging (MRI) scans in these infants.

STUDY DESIGN

Neonates ≥ 36 weeks' gestation with mild HIE and available MRI scans were identified. Mild HIE status was assigned to hyper alert infants with an exaggerated response to arousal and mild HIE as the highest grade of encephalopathy recorded. MRI scans were dichotomized as "injury" versus "no injury."

RESULTS

A total of 94.5% (257/272) neonates with mild HIE, referred for evaluation, received TH. MRI injury occurred in 38.2% (104/272) neonates and affected predominantly the white matter (49.0%, n = 51). Injury to the deep nuclear gray matter was identified in (10.1%) 20 infants, and to the cortex in 13.4% (n = 14 infants). In regression analyses (odds ratio [OR]; 95% confidence interval [CI]), history of fetal distress (OR = 0.52; 95% CI: 0.28-0.99) and delivery by caesarian section (OR = 0.54; 95% CI: 0.31-0.92) were associated with lower odds, whereas medical comorbidities during and after cooling were associated with higher odds of brain injury (OR = 2.31; 95% CI: 1.37-3.89).

CONCLUSION

Majority of neonates with mild HIE referred for evaluation are being treated with TH. Odds of neurological injury are over two-fold higher in those with comorbidities during and after cooling. Brain injury predominantly involved the white matter.

KEY POINTS

· Increasingly, neonates with mild HIE are being referred for consideration for hypothermia therapy.. · Drift in clinical practice shows growing number of neonates treated with hypothermia as having mild HIE.. · MRI data show that 38% of neonates with mild HIE have brain injury, predominantly in the white matter..

[Adherence to hypothermia guidelines in newborns with hypoxic-ischemic encephalopathy]

INTRODUCTION

We do not have population data in Spain on the application of therapeutic hypothermia (TH). The objective was to examine adherence to management standards during TH of infants with hypoxic-ischemic encephalopathy (HIE).

METHOD

Multicenter observational cohort study from the beginning of TH (year 2010) in 5 hospitals in a Spanish region, until year 2019.

RESULTS

133 patients were recruited, 72% diagnosed with moderate HIE and the rest of them with severe HIE. In 84% of infants, passive hypothermia was started at birth. Active TH was started at a median age of 5hours of life (IQR: 3.3-6.3), although the central targeted temperature (33-34°C) was reached at a median age of 3.5hours (IQR: 1-6). Those born extramural, initiated active TH 3.3hours on average later than those born intramural, but without differences in the age at which the targeted temperature was reached. Sedoanalgesia was used in 97%. The 100% were monitored with amplitude-integrated EEG and 59% with cerebral oxymetry. MRI was performed in 94% with moderate HIE vs. 65% with severe; P<.001. Neuron-specific enolase in cerebrospinal fluid was determined in 42%. The average duration of rewarming was median 10hours (IQR: 8-12), with no differences depending on the degree of HIE (P=.57).

CONCLUSIONS

The implementation of TH successfully met the standards. However, aspects of care that could be improved were detected. Auditing newborn care with HIE is crucial to achieving programs with a high quality of care in each region.

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

INTRODUCTION

There is a paucity of studies examining temporal trends in the incidence and mortality of moderate-to-severe hypoxic-ischemic encephalopathy (HIE) during the last decade of therapeutic hypothermia (TH).

METHODS

Multicenter cross-sectional study of all infants ≥35 weeks gestational age diagnosed with moderate-to-severe HIE within 6 h of birth in an extensive region of Spain between 2011 and 2019, in order to detect trend changes over time in the (1) annual incidence, (2) severity of neurological and systemic organ involvement, and (3) neonatal death from HIE.

RESULTS

Annual incidence rate of moderate-to-severe HIE was 0.84 (95% confidence interval [CI] 0.7-0.97) per 1,000 births, without trend changes over time (p = 0.8), although the proportion of severe HIE infants showed an average annual decline of 0.86 points (95% CI 0.75-0.98). There were 102 (70%) infants diagnosed with moderate HIE and 44 (30%) with severe HIE. TH was offered to 139/146 (95%) infants. Infants with clinical and/or electrical seizures showed a decreasing trend from 56 to 28% (p = 0.006). Mortality showed a nonstatistically significant decline (p = 0.4), and the severity of systemic damage showed no changes (p = 0.3). Obstetric characteristics remained unchanged, while higher perinatal pH values (p = 0.03) and Apgar scores (p = 0.05), and less need for resuscitation (p = 0.07), were found over time.

CONCLUSION

The annual incidence of moderate-to-severe HIE has stabilized at around 1 per 1,000 births, with a temporal trend toward a decrease in severe HIE infants and a slight decline of mortality. No association was found between temporal trends and changes in perinatal/obstetric characteristics over time.

LyTONEPAL: long term outcome of neonatal hypoxic encephalopathy in the era of neuroprotective treatment with hypothermia: a French population-based cohort

Background

Hypoxic-ischemic encephalopathy (HIE) is a rare neonatal condition affecting about 1‰ births. Despite a significant improvement in the management of this condition in the last ten years, HIE remains associated with high rates of death and severe neurological disability. From September 2015 to March 2017, a French national cohort of HIE cases was conducted to estimate the extent of long-term moderate and severe neurodevelopmental disability at 3 years and its determinants.

Methods

This prospective population-based cohort includes all moderate or severe cases of HIE, occurring in newborns delivered between 34 and 42 completed weeks of gestation and admitted to a neonatal intensive care unit. Detailed data on the pregnancy, delivery, and newborn until hospital discharge was collected from the medical records in maternity and neonatology units. All clinical examinations including biomarkers, EEG, and imaging were recorded. To ensure the completeness of HIE registration, a registry of non-included eligible neonates was organized, and the exhaustiveness of the cohort is currently checked using the national hospital discharge database. Follow-up is organized by the regional perinatal network, and 3 medical visits are planned at 18, 24 and 36 months. One additional project focused on early predictors, in particular early biomarkers, involves a quarter of the cohort.

Discussion

This cohort study aims to improve and update our knowledge about the incidence, the prognosis and the etiology of HIE, and to assess medical care. Its final objective is to improve the definition of this condition and develop prevention and management strategies for high-risk infants.

Trial registration

NCT02676063. Date of registration (Retrospectively Registered): February 8, 2016.

Population-Based Study of the National Implementation of Therapeutic Hypothermia in Infants with Hypoxic-Ischemic Encephalopathy

Data on the incidence of hypoxic-ischemic encephalopathy (HIE) in the first 6 hours of life together with the implementation of therapeutic hypothermia (TH) are relevant to delineate actions to achieve the lowest rates of neonatal mortality, morbidity, and long-term impact on health associated with HIE. This is population-based national survey study, including newborns ≥35 weeks of gestation with moderate-to-severe HIE from all level III neonatal care units, to provide the incidence of HIE for the period 2012-2013, and the implementation of TH up to June 2015 in Spain. Incidence rate was 0.77 per 1000 live births (95% confidence interval 0.72-0.83). By June 2015, 63% (57/90) of the units had implemented TH; 95% of them performed servo-controlled whole-body TH. For the 2-year period, 86% of the newborns diagnosed with moderate-to-severe HIE received TH. Active TH increased in use from 78% in 2012 to 85% in 2013 (p = 0.01). The main reasons for not cooling were a delay in the diagnosis (31/682) and the fact that the treatment was not offered (20/682). Interhospital patient transfer was performed using passive hypothermia, by appropriately trained personnel in 61% of centers. Eighteen percent of newborns with moderate or severe HIE died, without significant differences between the 2 years. Up-to-date knowledge of the national coverage of neonatal care of infants with HIE in developed countries is a prerequisite to reducing the load of HIE in this area and to facilitating coordinated, eliminate investigation.

The Frequency and Severity of Magnetic Resonance Imaging Abnormalities in Infants with Mild Neonatal Encephalopathy

OBJECTIVE

To assess and contrast the incidence and severity of abnormalities on cerebral magnetic resonance imaging (MRI) between infants with mild, moderate, and severe neonatal encephalopathy who received therapeutic hypothermia.

STUDY DESIGN

This retrospective cohort studied infants with mild, moderate, and severe neonatal encephalopathy who received therapeutic hypothermia at a single tertiary neonatal intensive care unit between 2013 and 2015. Two neuroradiologists masked to the clinical condition evaluated brain MRIs for cerebral injury after therapeutic hypothermia using the Barkovich classification system. Additional abnormalities not included in this classification system were also noted. The rate, pattern, and severity of abnormalities/injury were compared across the grades of neonatal encephalopathy.

RESULTS

Eighty-nine infants received therapeutic hypothermia and met study criteria, 48 with mild neonatal encephalopathy, 35 with moderate neonatal encephalopathy, and 6 with severe neonatal encephalopathy. Forty-eight infants (54%) had an abnormality on MRI. There was no difference in the rate of overall MRI abnormalities by grade of neonatal encephalopathy (mild neonatal encephalopathy 54%, moderate neonatal encephalopathy 54%, and severe neonatal encephalopathy 50%; P= .89). Basal ganglia/thalamic injury was more common in those with severe neonatal encephalopathy (mild neonatal encephalopathy 4%, moderate neonatal encephalopathy 9%, severe neonatal encephalopathy 34%; P = .03). In contrast, watershed injury did not differ between neonatal encephalopathy grades (mild neonatal encephalopathy 36%, moderate neonatal encephalopathy 32%, severe neonatal encephalopathy 50%; P = .3).

CONCLUSION

Mild neonatal encephalopathy is commonly associated with MRI abnormalities after therapeutic hypothermia. The grade of neonatal encephalopathy during the first hours of life may not discriminate adequately between infants with and without cerebral injury noted on MRI after therapeutic hypothermia.

[Incidence of hypoxic-ischaemic encephalopathy and use of therapeutic hypothermia in Spain]

INTRODUCTION

There are no data on the incidence of hypoxic-ischaemic encephalopathy (HIE) and the implementation of therapeutic hypothermia (TH) in Spain.

METHODS

This is a cross-sectional, national study, performed using an on-line questionnaire targeting level III neonatal care units in Spain. Participants were requested to provide data of all newborns ≥ 35 weeks of gestational age diagnosed with moderate-severe HIE over a two year-period (2012-2013), and of the implementation of TH up to June 2015.

RESULTS

All (90) contacted hospitals participated. HIE incidence rate was 0.77/1000 live newborns (95% CI 0.72 - 0.83). During 2012-2013, 86% of the newborns diagnosed with moderate-severe HIE received TH (active or passive). Active TH was increasingly used, from 78% in 2012 to 85% in 2013 (P=.01). Of the 14% that did not receive TH, it was mainly due to a delay in the diagnosis or inter-hospital transfer, and to the fact that the treatment was not offered. More than half (57%) were born in hospitals where TH was not provided, and passive hypothermia was used for inter-hospital patient transfer, and in 39% of the cases by inappropriately trained personnel. By June 2015, 57 out of 90 centres had implemented TH, of which 54 performed whole-body TH (using servo-controlled devices). The geographical distribution of centres with active TH, and the number of newborn that received TH, was heterogeneous.

CONCLUSIONS

The incidence of moderate-severe HIE is homogeneous across Spanish territory. Significant progress is being made in the implementation of TH, however it is necessary to increase the availability of active TH between Autonomous Communities, to improve early diagnosis, and to guarantee high quality patient transfer to referral centres.

MRI and spectroscopy in (near) term neonates with perinatal asphyxia and therapeutic hypothermia

BACKGROUND

Previous studies have demonstrated the association of abnormalities on diffusion-weighted MRI (DW-MRI) and proton magnetic resonance spectroscopy (¹H-MRS) in infants with perinatal asphyxia. The use of therapeutic hypothermia might change this association.

AIM

To study the association between DW-MRI and ¹H-MRS and outcome after perinatal asphyxia and therapeutic hypothermia in infants with a gestational age of ≥36 weeks.

PATIENTS AND METHODS

Infants with perinatal asphyxia and therapeutic hypothermia (n=88) were included when an MR examination was performed within 7 days after birth. Apparent diffusion coefficient (ADC) values of the basal ganglia and thalamus were calculated, as were lactate/N-acetylaspartate (LAC/NAA) and N-acetylaspartate/choline (NAA/Cho) ratios. Death or an abnormal neurodevelopment at ≥24 months was considered an adverse outcome. Receiver operating characteristic analysis was performed to determine cut-off levels.

RESULTS

Of the 88 infants, 22 died and 7 had an adverse neurodevelopmental outcome. In infants with an adverse outcome, ADC values of the basal ganglia and thalamus were significantly lower, and Lac/NAA ratios were significantly higher than in infants with a normal outcome. Areas under the curve of ADC of the basal ganglia, thalami and Lac/NAA ratio were 0.89, 0.88 and 0.87, respectively. NAA/Cho ratios were in this cohort not associated with outcome.

CONCLUSIONS

During and after therapeutic hypothermia, low ADC values and high Lac/NAA ratios of the basal ganglia and thalamus are associated with an adverse outcome in infants with perinatal asphyxia.

Pharmacological models and approaches for pathophysiological conditions associated with hypoxia and oxidative stress

Hypoxia is the failure of oxygenation at the tissue level, where the reduced oxygen delivered is not enough to satisfy tissue demands. Metabolic depression is the physiological adaptation associated with reduced oxygen consumption, which evidently does not cause any harm to organs that are exposed to acute and short hypoxic insults. Oxidative stress (OS) refers to the imbalance between the generation of reactive oxygen species (ROS) and the ability of endogenous antioxidant systems to scavenge ROS, where ROS overwhelms the antioxidant capacity. Oxidative stress plays a crucial role in the pathogenesis of diseases related to hypoxia during intrauterine development and postnatal life. Thus, excessive ROS are implicated in the irreversible damage to cell membranes, DNA, and other cellular structures by oxidizing lipids, proteins, and nucleic acids. Here, we describe several pathophysiological conditions and in vivo and ex vivo models developed for the study of hypoxic and oxidative stress injury. We reviewed existing literature on the responses to hypoxia and oxidative stress of the cardiovascular, renal, reproductive, and central nervous systems, and discussed paradigms of chronic and intermittent hypobaric hypoxia. This systematic review is a critical analysis of the advantages in the application of some experimental strategies and their contributions leading to novel pharmacological therapies.

Establishing a hypothermia service for infants with suspected hypoxic-ischemic encephalopathy

The translation of new treatments based upon established evidence into clinical practice is often difficult. The establishment of a therapeutic hypothermia (TH) service and a related cooling register would provide the opportunity to examine how a new therapy becomes implemented in a country or region. The objectives of a TH program should be: to provide guidance to clinicians who are considering the introduction of this new therapy; to ensure standardized clinical practices; to audit the implementation and conduct of TH; to provide surveillance for cooling-related adverse effects; and to evaluate the subsequent neurodevelopmental outcome. Prior to the use of TH, the most important practices to prioritize during its implementation should be identified and include the following: ensure timely identification of infants with neonatal encephalopathy; develop a coordinated system with the local or regional referral cooling center; develop a transport team capable of performing cooling during transport; ensure that each participating unit has access to a national encephalopathy register, and have developmental follow-up arrangements in place that are appropriate and uniform for the region/country.

Early identification of brain injury in infants with hypoxic ischemic encephalopathy at high risk for severe impairments: accuracy of MRI performed in the first days of life

Background

Despite therapeutic hypothermia 30-70% of newborns with moderate or severe hypoxic ischemic encephalopathy will die or survive with significant long-term impairments. Magnetic resonance imaging (MRI) in the first days of life is being used for early identification of these infants and end of life decisions are relying more and more on it. The purpose of this study was to evaluate how MRI performed around day 4 of life correlates with the ones obtained in the second week of life in infants with hypoxic-ischemic encephalopathy (HIE) treated with hypothermia.

Methods

Prospective observational cohort study between April 2009 and July 2011. Consecutive newborns with HIE evaluated for therapeutic hypothermia were included. Two sequential MR studies were performed: an •early’ study around the 4th day of life and a •late’ study during the second week of life. MRI were assessed and scored by two neuroradiologists who were blinded to the clinical condition of the infants.

Results

Forty-eight MRI scans were obtained in the 40 newborns. Fifteen infants underwent two sequential MR scans. The localization, extension and severity of hypoxic-ischemic injury in early and late scans were highly correlated. Hypoxic-ischemic injury scores from conventional sequences (T1/T2) in the early MRI correlated with the scores of the late MRI (Spearman ρ = 0.940; p < .001) as did the scores between diffusion-weighted images in early scans and conventional images in late MR studies (Spearman ρ = 0.866; p < .001). There were no significant differences in MR images between the two sequential scans.

Conclusions

MRI in the first days of life may be a useful prognostic tool for clinicians and can help parents and neonatologist in medical decisions, as it highly depicts hypoxic-ischemic brain injury seen in scans performed around the second week of life.