Hyperglycaemia in infants with hypoxic-ischaemic encephalopathy is associated with improved outcomes after therapeutic hypothermia: a post hoc analysis of the CoolCap Study

Neonatal encephalopathy multiorgan scoring systems: systematic review

Introduction

Neonatal encephalopathy (NE) is a condition with multifactorial etiology that causes multiorgan injury to neonates. The severity of multiorgan dysfunction (MOD) in NE varies, with therapeutic hypothermia (TH) as the standard of care. The aim is to identify current approaches used to assess and determine an optimum scoring system for MOD in NE.

Methods

The systematic review conformed to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. An electronic search was conducted using PubMed, EMBASE, MEDLINE, Cochrane Central Register of Controlled Trials, Scopus, and CINAHL for studies of scoring systems for MOD in NE.

Results

The search yielded 628 articles of which 12 studies were included for data extraction and analysis. Five studies found a positive correlation between the severity of NE and MOD. There was significant heterogeneity across the scoring systems, including the eligibility criteria for participants, the methods assessing specific organ systems, the length of follow-up, and adverse outcomes. The neurological, hepatic, cardiovascular, respiratory, hematological, and renal systems were included in most studies while the gastrointestinal system was only in three studies. The definitions for hepatic, renal, and respiratory systems dysfunction were most consistent while the cardiovascular system varied the most.

Discussion

A NE multiorgan scoring system should ideally include the renal, hepatic, respiratory, neurological, hematological, and cardiovascular systems. Despite the heterogeneity between the studies, these provide potential candidates for the standardization of MOD scoring systems in NE. Validation is needed for the parameters with adequate length of follow-up beyond the neonatal period. Additionally, the evaluation of MOD may be affected by TH considering its multiorgan effects.

Glucose instability and outcomes of neonates with hypoxic ischemic encephalopathy undergoing therapeutic hypothermia

BACKGROUND

To investigate the prevalence and associated outcomes of glucose abnormalities in infants with hypoxic ischemic encephalopathy (HIE) undergoing therapeutic hypothermia (TH).

METHODS

Glucose values were reviewed in all HIE infants. Pearson's correlation was used to assess the association of hypo- and hyperglycemic episodes with neonatal brain MRI and neurodevelopmental outcomes (NDO) at 12 & 24 months.

RESULTS

Of 153 infants included, 31, 56 and 43 had episodes of hypo-, hyperglycemia and combined, respectively. Hyperglycemia and combined hypo/hyper had higher mortality (p = 0.035), seizures (p = 0.009), and longer hospitalization (p = 0.023). Hypo- and hyperglycemia were associated with parenchymal hemorrhages (p = 0.028 & p = 0.027, respectively). Hypoglycemia was associated with restricted diffusion (p = 0.014), while hyperglycemia was associated with cortical injuries (p = 0.045). Each hour of hyper- or hypoglycemia was associated with 5.2-5.8 times unfavorable outcomes (p < 0.001).

CONCLUSION

Blood glucose aberrations were detrimental in HIE infants treated with TH. Optimizing glucose management is crucial in this setting.

Hypoglycaemia and hyperglycaemia in neonatal encephalopathy: a systematic review and meta-analysis

IMPORTANCE

Although hypoglycaemia and hyperglycaemia represent the most common metabolic problem in neonates, there is still uncertainty regarding the effects of glucose homoeostasis on the neurological outcomes of infants with neonatal encephalopathy (NE).

OBJECTIVE

To systematically investigate the association between neonatal hypoglycaemia and hyperglycaemia with adverse outcome in children who suffered from NE.

STUDY SELECTION

We searched Pubmed, Embase and Web of Science databases to identify studies which reported prespecified outcomes and compared infants with NE who had been exposed to neonatal hypoglycaemia or hyperglycaemia with infants not exposed.

DATA ANALYSIS

We assessed the risk of bias (ROBINS-I), quality of evidence (Grading of Recommendations, Assessment, Development and Evaluation (GRADE)) for each of the studies. RevMan was used for meta-analysis (inverse variance, fixed effects).

MAIN OUTCOME

Death or neurodevelopmental outcomes at 18 months of age or later.

RESULTS

82 studies were screened, 28 reviewed in full and 12 included. Children who were exposed to neonatal hypoglycaemia had higher odds of neurodevelopmental impairment or death (6 studies, 685 infants; 40.6% vs 25.4%; OR=2.17, 95% CI 1.46 to 3.25; p=0.0001). Neonatal exposure to hyperglycaemia was associated with death or neurodisability at 18 months or later (7 studies, 807 infants; 46.1% vs 28.0%; OR=3.07, 95% CI 2.17 to 4.35; p<0.00001). These findings were confirmed in the subgroup analysis, which included only the infants who underwent therapeutic hypothermia.

CONCLUSIONS

These data suggest that neonatal hypoglycaemia and hyperglycaemia may be associated with the neurodevelopmental outcome later on in infants with NE. Further studies with long-term follow-up are needed to optimise the metabolic management of these high-risk infants.

PROSPERO REGISTRATION NUMBER

CRD42022368870.

Early Glycemic State and Outcomes of Neonates With Hypoxic-Ischemic Encephalopathy

OBJECTIVES

In infants with hypoxic-ischemic encephalopathy (HIE), conflicting information on the association between early glucose homeostasis and outcome exists. We characterized glycemic profiles in the first 12 hours after birth and their association with death and neurodevelopmental impairment (NDI) in neonates with moderate or severe HIE undergoing therapeutic hypothermia.

METHODS

This post hoc analysis of the High-dose Erythropoietin for Asphyxia and Encephalopathy trial included n = 491 neonates who had blood glucose (BG) values recorded within 12 hours of birth. Newborns were categorized based on their most extreme BG value. BG >200 mg/dL was defined as hyperglycemia, BG <50 mg/dL as hypoglycemia, and 50 to 200 mg/dL as euglycemia. Primary outcome was defined as death or any NDI at 22 to 36 months. We calculated odds ratios for death or NDI adjusted for factors influencing glycemic state (aOR).

RESULTS

Euglycemia was more common in neonates with moderate compared with severe HIE (63.6% vs 36.6%; P < .001). Although hypoglycemia occurred at similar rates in severe and moderate HIE (21.4% vs 19.5%; P = .67), hyperglycemia was more common in severe HIE (42.3% vs 16.9%; P < .001). Compared with euglycemic neonates, both, hypo- and hyperglycemic neonates had an increased aOR (95% confidence interval) for death or NDI (2.62; 1.47-4.67 and 1.77; 1.03-3.03) compared to those with euglycemia. Hypoglycemic neonates had an increased aOR for both death (2.85; 1.09-7.43) and NDI (2.50; 1.09-7.43), whereas hyperglycemic neonates had increased aOR of 2.52 (1.10-5.77) for death, but not NDI.

CONCLUSIONS

Glycemic profile differs between neonates with moderate and severe HIE, and initial glycemic state is associated death or NDI at 22 to 36 months.

Severity and duration of dysglycemia and brain injury among patients with neonatal encephalopathy

Background

Evidence is needed to inform thresholds for glycemic management in neonatal encephalopathy (NE). We investigated how severity and duration of dysglycemia relate to brain injury after NE.

Methods

A prospective cohort of 108 neonates ≥36 weeks gestational age with NE were enrolled between August 2014 and November 2019 at the Hospital for Sick Children, in Toronto, Canada. Participants underwent continuous glucose monitoring for 72 h, MRI at day 4 of life, and follow-up at 18 months. Receiver operating characteristic curves were used to assess the predictive value of glucose measures (minimum and maximum glucose, sequential 1 mmol/L glucose thresholds) during the first 72 h of life (HOL) for each brain injury pattern (basal ganglia, watershed, focal infarct, posterior-predominant). Linear and logistic regression analyses were used to assess the relationship between abnormal glycemia and 18-month outcomes (Bayley-III composite scores, Child Behavior Checklist [CBCL] T-scores, neuromotor score, cerebral palsy [CP], death), adjusting for brain injury severity.

Findings

Of 108 neonates enrolled, 102 (94%) had an MRI. Maximum glucose during the first 48 HOL best predicted basal ganglia (AUC = 0.811) and watershed (AUC = 0.858) injury. Minimum glucose was not predictive of brain injury (AUC <0.509). Ninety-one (89%) infants underwent follow-up assessments at 19.0 ± 1.7 months. A glucose threshold of >10.1 mmol/L during the first 48 HOL was associated with 5.8-point higher CBCL Internalizing Composite T-score (P = 0.029), 0.3-point worse neuromotor score (P = 0.035), 8.6-fold higher odds for CP diagnosis (P = 0.014). While the glucose threshold of >10.1 mmol/L during the first 48 HOL was associated with higher odds of the composite outcome of severe disability or death (OR 3.0, 95% CI 1.0-8.4, P = 0.042), it was not associated with the composite outcome of moderate-to-severe disability or death (OR 0.9, 95% CI 0.4-2.2, P = 0.801). All associations with outcome lost significance after adjusting for brain injury severity.

Interpretation

Maximum glucose concentration in the first 48 HOL is predictive of brain injury after NE. Further trials are needed to assess if protocols to control maximum glucose concentrations improve outcomes after NE.

Funding

Canadian Institutes for Health Research, National Institutes of Health, and SickKids Foundation.

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.

Glucose-to-lactate ratio and neurodevelopment in infants with hypoxic-ischemic encephalopathy: an observational study

We aimed to assess the glucose and lactate kinetics during therapeutic hypothermia (TH) in infants with hypoxic-ischemic encephalopathy and its relationship with longitudinal neurodevelopment. We measured glucose and lactate concentrations before TH and on days 2 and 3 in infants with mild, moderate, and severe hypoxic-ischemic encephalopathy (HIE). Neurodevelopment was assessed at 2 years. Participants were grouped according to the neurodevelopmental outcome into favorable (FO) or unfavorable (UFO). Eighty-eight infants were evaluated at follow-up, 34 for the FO and 54 for the UFO group. Severe hypo- (< 2.6 mmol/L) and hyperglycemia (> 10 mmol/L) occurred in 18% and 36% from the FO and UFO groups, respectively. Glucose-to-lactate ratio on day 1 was the strongest predictor of unfavorable metabolic outcome (OR 3.27 [Formula: see text] 1.81, p = 0.032) when adjusted for other clinical and metabolic variables, including Sarnat score.

CONCLUSION

Glucose-to-lactate ratio on day 1 may represent a new risk marker for infants with HIE undergoing TH.

WHAT IS KNOWN

• Glucose and lactate are key metabolic fuels during neonatal hypoglycemia. This suggests that their concentrations may influence the neurodevelopmental outcome of neonates experiencing hypoxic-hischemic encephalopathy (HIE).

WHAT IS NEW

• We describe the relative availbility of glucose and lactate before and during theraputic hypothermia in neonates with HIE.

Risk factors for unfavorable outcome at discharge of newborns with hypoxic-ischemic encephalopathy in the era of hypothermia

OBJECTIVE

To re-visit short-term outcomes and associated risk factors of newborns with hypoxic-ischemic encephalopathy (HIE) in an era where hypothermia treatment (HT) is widespread.

METHODS

This is a prospective population-based cohort in French neonatal intensive care units (NICU). Neonates born at or after 34 weeks of gestational age with HIE were included; main outcomes were in-hospital death and discharge with abnormal or normal MRI. Associations of early perinatal risk factors, present at birth or at admission to NICU, with these outcomes were studied.

RESULTS

A total of 794 newborns were included and HT was administered to 670 (84.4%); 18.3% died and 28.5% and 53.2% survived with abnormal and normal MRI, respectively. Severe neurological status, Apgar score at 5 mn ≤5, lactate at birth ≥11 mMoles/l, and glycemia ≥100 mg/dL at admission were associated with an increased risk of death (relative risk ratios (aRRR) (95% CI) 19.93 (10.00-39.70), 2.89 (1.22-1.62), 3.06 (1.60-5.83), and 2.55 (1.38-4.71), respectively). Neurological status only was associated with survival with abnormal MRI (aRRR (95% CI) 1.76 (1.15-2.68)).

CONCLUSION

Despite high use of HT in this cohort, 46.8% died or presented brain lesions. Early neurological and biological examinations were associated with unfavorable outcomes and these criteria could be used to target children who warrant further neuroprotective treatment.

TRIAL REGISTRATION

Clinical trial registry, NCT02676063, ClinicalTrials.gov.

IMPACT

In this population-based cohort of newborns with HIE where 84% received hypothermia, 46.8% still had an unfavorable evolution (death or survival with abnormal MRI). Risk factors for death were high lactate, low Apgar score, severe early neurological examination, and high glycaemia. While studies have established risk factors for HIE, few have focused on early perinatal factors associated with short-term prognosis. This French population-based cohort updates knowledge about early risk factors for adverse outcomes in the era of widespread cooling. In the future, criteria associated with an unfavorable evolution could be used to target children who would benefit from another neuroprotective strategy with hypothermia.

Cerebral Effects of Neonatal Dysglycemia

This article summarizes the available evidence reporting the relationship between perinatal dysglycemia and long-term neurodevelopment. We review the physiology of perinatal glucose metabolism and discuss the controversies surrounding definitions of perinatal dysglycemia. We briefly review the epidemiology of hypoglycemia and hyperglycemia in fetal, preterm, and term infants. We discuss potential pathophysiologic mechanisms contributing to dysglycemia and its effect on neurodevelopment. We highlight current strategies to prevent and treat dysglycemia in the context of neurodevelopmental outcomes. Finally, we discuss areas of future research and the potential role of continuous glucose monitoring.

Therapeutic hypothermia in neonatal hypoxic encephalopathy: A systematic review and meta-analysis

Background

Therapeutic hypothermia (TH) is regarded as the most efficacious therapy for neonatal hypoxic encephalopathy. However, limitations in previous systematic reviews and the publication of new data necessitate updating the evidence. We conducted this up-to-date systematic review to evaluate the effects of TH in neonatal encephalopathy on clinical outcomes.

Methods

In this systematic review and meta-analysis, we searched Medline, Cochrane Library, Embase, LIVIVO, Web of Science, Scopus, CINAHL, major trial registries, and grey literature (from inception to October 31, 2021), for randomized controlled trials (RCT) comparing TH vs normothermia in neonatal encephalopathy. We included RCTs enrolling neonates (gestation ≥35 weeks) with perinatal asphyxia and encephalopathy, who received either TH (temperature ≤34°C) initiated within 6 hours of birth for ≥48 hours, vs no cooling. We excluded non-RCTs, those with delayed cooling, or cooling to >34°C. Two authors independently appraised risk-of-bias and extracted data on mortality and neurologic disability at four time points: neonatal (from randomization to discharge/death), infancy (18-24 months), childhood (5-10 years), and long-term (>10 years). Other outcomes included seizures, EEG abnormalities, and MRI findings. Summary data from published RCTs were pooled through fixed-effect meta-analysis.

Results

We identified 36 863 citations and included 39 publications representing 29 RCTs with 2926 participants. Thirteen studies each had low, moderate, and high risk-of-bias. The pooled risk ratios (95% confidence interval, CI) were as follows: neonatal mortality: 0.87 (95% CI = 0.75, 1.00), n = 2434, I² = 38%; mortality at 18-24 months: 0.88 (95% CI = 0.78, 1.01), n = 2042, I² = 51%; mortality at 5-10 years: 0.81 (95% CI = 0.62, 1.04), n = 515, I² = 59%; disability at 18-24 months: 0.62 (95% CI = 0.52, 0.75), n = 1440, I² = 26%; disability at 5-10 years: 0.68 (95% CI = 0.52, 0.90), n = 442, I² = 3%; mortality or disability at 18-24 months: 0.78 (95% CI = 0.72, 0.86), n = 1914, I² = 54%; cerebral palsy at 18-24 months: 0.63 (95% CI = 0.50, 0.78), n = 1136, I² = 39%; and childhood cerebral palsy: 0.63 (95% CI = 0.46, 0.85), n = 449, I² = 0%. Some outcomes showed significant differences by study-setting; the risk ratio (95% CI) for mortality at 18-24 months was 0.79 (95% CI = 0.66,0.93), n = 1212, I² = 7% in high-income countries, 0.67 (95% CI = 0.41, 1.09), n = 276, I² = 0% in upper-middle-income countries, and 1.18 (95% CI = 0.94, 1.47), n = 554, I² = 75% in lower-middle-income countries. The corresponding pooled risk ratios for ‘mortality or disability at 18-24 months’ were 0.77 (95% CI = 0.69, 0.86), n = 1089, I² = 0%; 0.56 (95% CI = 0.41, 0.78), n = 276, I² = 30%; and 0.92 (95% CI = 0.77, 1.09), n = 549, I² = 86% respectively. Trials with low risk of bias showed risk ratio of 0.97 (95% CI = 0.80, 1.16, n = 1475, I² = 62%) for neonatal mortality, whereas trials with higher risk of bias showed 0.71 (95% CI = 0.55, 0.91), n = 959, I² = 0%. Likewise, risk ratio for mortality at 18-24 months was 0.96 (95% CI = 0.83, 1.13), n = 1336, I² = 58% among low risk-of-bias trials, but 0.72 (95% CI = 0.56, 0.92), n = 706, I² = 0%, among higher risk of bias trials.

Conclusions

Therapeutic hypothermia for neonatal encephalopathy reduces neurologic disability and cerebral palsy, but its effect on neonatal, infantile and childhood mortality is uncertain. The setting where it is implemented affects the outcomes. Low(er) quality trials overestimated the potential benefit of TH.

Nutrition and management of glycemia in neonates with neonatal encephalopathy treated with hypothermia

Adequate nutrition and glycemic homeostasis are increasingly recognized as potentially neuroprotective for the developing brain. In the context of hypoxia-ischemia, evidence is scarce regarding optimal nutritional support and administration route, as well as the short- and long-term consequences of such interventions. In this review, we summarize current knowledge on disturbances of brain metabolism of glucose and substrates by hypoxia-ischemia, and compound effects of these mechanisms on brain injury characterized by specific patterns on EEG and MRI. Risks and benefits of nutrition delivery via parenteral or enteral routes are examined. Nutrition could mitigate adverse neurodevelopmental outcomes, and the impact of nutritional strategies and specific nutritional interventions are reviewed. Limited literature highlights the need for further studies to understand the changes in energy metabolism during and after hypoxic-ischemic injury, to optimize nutritional regimens and glucose management, and to inform the neuroprotective role of nutrition.

Hyperglycaemia in the Newborn Infant. Physiology Verses Pathology

Hyperglycemia is common in newborns requiring intensive care, particularly in preterm infants, in sepsis and following perinatal hypoxia. The clinical significance, and optimal intervention strategy varies with context, but hyperglycaemia is associated with increased mortality and morbidity. The limited evidence for optimal clinical targets mean controversy remains regarding thresholds for intervention, and management strategies. The first consideration in the management of hyperglycaemia must be to ascertain potentially treatable causes. Calculation of the glucose infusion rate (GIR) to insure this is not excessive, is critical but the use of insulin is often helpful in the extremely preterm infant, but is associated with an increased risk of hypoglycaemia. The use of continuous glucose monitoring (CGM) has recently been demonstrated to be helpful in targeting glucose control, and reducing the risk from hypoglycaemia in the preterm infant. Its use in other at risk infants remains to be explored, and further studies are needed to provide a better understanding of the optimal glucose targets for different clinical conditions. In the future the combination of CGM and advances in computer algorithms, to provide intelligent closed loop systems, could allow a safer and more personalized approached to management.

Abnormalities in evoked potentials associated with abnormal glycemia and brain injury in neonatal hypoxic-ischemic encephalopathy

OBJECTIVE

To investigate how functional integrity of ascending sensory pathways measured by visual and somatosensory evoked potentials (VEP & SEP) is associated with abnormal glycemia and brain injury in newborns treated with hypothermia for hypoxic-ischemic encephalopathy (HIE).

METHODS

Fifty-four neonates ≥ 36 weeks gestational age with HIE underwent glucose testing, VEPs, SEPs, and magnetic resonance imaging (MRI) the first week of life. Minimum and maximum glucose values recorded prior to evoked potential (EP) testing were compared with VEP and SEP measures using generalized estimating equations. Relationships between VEP and SEP measures and brain injury on MRI were assessed.

RESULTS

Maximum glucose is associated with decreased P200 amplitude, and increased odds that N300 peak will be delayed/absent. Minimum glucose is associated with decreased P22 amplitude. Presence of P200 and N300 peaks is associated with decreased odds of brain injury in the visual processing pathway, with delayed/absent N300 peak associated with increased odds of brain injury in posterior white matter.

CONCLUSIONS

Deviations from normoglycemia are associated with abnormal EPs, and abnormal VEPs are associated with brain injury on MRI in cooled neonates with HIE.

SIGNIFICANCE

Glucose is a modifiable risk factor associated with atypical brain function in neonates with HIE despite hypothermia treatment.

Effects of antenatal dexamethasone and hyperglycemia on cardiovascular adaptation to asphyxia in preterm fetal sheep

Antenatal glucocorticoids improve outcomes among premature infants but are associated with hyperglycemia, which can exacerbate hypoxic-ischemic injury. It is still unclear how antenatal glucocorticoids or hyperglycemia modulate fetal cardiovascular adaptations to severe asphyxia. In this study, preterm fetal sheep received either saline or 12 mg im maternal dexamethasone, followed 4 h later by complete umbilical cord occlusion (UCO) for 25 min. An additional cohort of fetuses received titrated glucose infusions followed 4 h later by UCO to control for the possibility that hyperglycemia contributed to the cardiovascular effects of dexamethasone. Fetuses were studied for 7 days after UCO. Maternal dexamethasone was associated with fetal hyperglycemia (P < 0.001), increased arterial pressure (P < 0.001), and reduced femoral (P < 0.005) and carotid (P < 0.05) vascular conductance before UCO. UCO was associated with bradycardia, femoral vasoconstriction, and transient hypertension. For the first 5 min of UCO, fetal blood pressure in the dexamethasone-asphyxia group was greater than saline-asphyxia (P < 0.001). However, the relative increase in arterial pressure was not different from saline-asphyxia. Fetal heart rate and femoral vascular conductance fell to similar nadirs in both saline and dexamethasone-asphyxia groups. Dexamethasone did not affect the progressive decline in femoral vascular tone or arterial pressure during continuing UCO. By contrast, there were no effects of glucose infusions on the response to UCO. In summary, maternal dexamethasone but not fetal hyperglycemia increased fetal arterial pressure before and for the first 5 min of prolonged UCO but did not augment the cardiovascular adaptations to acute asphyxia.

Continuous glucose monitoring profile during therapeutic hypothermia in encephalopathic infants with unfavorable outcome

BACKGROUND

The relation between glucose homeostasis and outcome in hypoxic-ischemic encephalopathy (HIE) is unclear. To investigate whether glucose abnormalities assessed by using continuous interstitial glucose monitoring (CGM) correlate with later neurological outcomes in HIE.

METHODS

Prospective cohort study recruiting full-term neonates who received therapeutic hypothermia for HIE. CGM devices were placed soon after birth and recorded glucose profile for 3 days. The association between hypoglycemia (≤50 mg/dL), hyperglycemia (>144 mg/dL) and primary outcome defined as death or moderate or severe disability was examined with generalized estimating equations adjusted for Apgar scores, umbilical artery pH and base deficit. Neurodevelopmental outcome was assessed between 18 and 24 months.

RESULTS

Fifty-four neonates had outcome data available for the analysis; 19 of them (35%) had adverse outcome. Longer duration of hypoglycemia (OR 7.1, 95% CI 1.8-20.3, P < 0.001) and hyperglycemia (OR 5.4, 95% CI 1.6-15.7, P < 0.001), a greater area under the hypoglycemic (OR 2.6, 95% CI 1.4-4.6, P = 0.04) and hyperglycemic (OR 6.4, 95% CI 1.9-16.3, P < 0.001) curve were significantly associated with adverse outcomes.

CONCLUSION

Both hyper and hypoglycemia may be associated with adverse outcome in neonates with HIE. Future studies are needed to assess their prognostic association with neurological outcome.

IMPACT

Glucose abnormalities during therapeutic hypothermia are associated with later neurological outcomes.Increased glucose variability correlates to the neurological outcome between 18 and 24 months.This study provides the first data on the continuous glucose profile in a group of HIE infants followed up to 2 years of age.Glucose homeostasis represents a key point in the management of HIE patients.Further research is needed to find the appropriate glycemic target in this population.

Real time continuous glucose monitoring in neonatal intensive care

Hypoglycaemia and hyperglycaemia are common in infants requiring intensive care and are associated with worse clinical outcomes. However, glucose levels are taken infrequently, and there remains controversy regarding optimal management. In adults and children continuous glucose monitoring (CGM) is now established as an important adjunct to caring for patients at risk from dysglycaemia. This technology is also increasingly providing insights into glucose regulation in the newborn, demonstrating significant periods of clinically silent hypoglycaemia and hyperglycaemia. This baseline data will be important to allow the significance of glucose dysregulation on long-term outcomes to be assessed. Small studies have also shown the potential for CGM to safely support targeting of glucose control in preterm infants, and a large multicentre trial is ongoing. Current technology is not specifically designed for use in NICU, but with rapid technological developments, CGM holds promise for the future care of babies in NICU.

Early Glycemic Profile Is Associated with Brain Injury Patterns on Magnetic Resonance Imaging in Hypoxic Ischemic Encephalopathy

OBJECTIVE

To investigate whether the early glycemic profile in infants with hypoxic ischemic encephalopathy is associated with distinct patterns of brain injury on magnetic resonance imaging (MRI).

STUDY DESIGN

We performed a secondary analysis of 178 prospectively enrolled infants who received therapeutic hypothermia for hypoxic ischemic encephalopathy. Glycemic profiles were identified by glucose concentrations within 24 hours after birth: normoglycemia (all glucose concentrations of >47 to ≤150 mg/dL; n = 62); hypoglycemia (≥1 concentration ≤47 mg/dL; n = 17); hyperglycemia (≥1 concentration >150 mg/dL; n = 76); and labile glucose (both hypoglycemia and hyperglycemia; n = 23). Patterns of brain injury were identified for 151 infants based on Barkovich scores from the postrewarming brain MRIs at a median age of 9 days.

RESULTS

A normal brain MRI was reported in 37 of 62 infants (60%) with normal blood glucose values compared with 37 of 116 infants (32%) with an abnormal glucose profile (adjusted for Sarnat stage of encephalopathy and Apgar score at 5 minutes; P = .02). The distribution of MRI patterns of brain injury differed among the glycemic groups (P = .03). The odds of predominant watershed or focal-multifocal injury was higher in infants with hypoglycemia (aOR, 6; 95% CI, 1.5-24.2) and labile glucose (6.6; 95% CI, 1.6-27) compared with infants with normoglycemia. Infants with labile glucose had higher odds (5.6; 95% CI, 1.1-29.3) of predominant basal ganglia or global injury compared with infants with normal blood glucose values.

CONCLUSIONS

The early glycemic profile in infants with hypoxic ischemic encephalopathy is associated with specific patterns of brain injury on MRI. Further investigation is needed to explore its prognostic significance and role as a phenotype biomarker.

Body Temperature, Heart Rate, and Short-Term Outcome of Cooled Infants

Therapeutic hypothermia following neonatal encephalopathy is neuroprotective. However, approximately one in two cooled infants still die or develop permanent neurological impairments. Further understanding of variables associated with the effectiveness of cooling is important to improve the therapeutic regimen. To identify clinical factors associated with short-term outcomes of cooled infants, clinical data of 509 cooled infants registered to the Baby Cooling Registry of Japan between 2012 and 2014 were evaluated. Independent variables of death during the initial hospitalization and survival discharge from the cooling hospital at ≤28 days of life were assessed. Death was associated with higher Thompson scores at admission (p < 0.001); higher heart rates after 3-72 hours of cooling (p < 0.001); and higher body temperature after 24 hours of cooling (p = 0.002). Survival discharge was associated with higher 10 minutes Apgar scores (p < 0.001); higher blood pH and base excess (both p < 0.001); lower Thompson scores (at admission and after 24 hours of cooling; both p < 0.001); lower heart rates at initiating cooling (p = 0.003) and after 24 hours of cooling (p < 0.001) and lower average values after 3-72 hours of cooling (p < 0.001); higher body temperature at admission (p < 0.001); and lower body temperature after 24 hours and lower mean values after 3-72 hours of cooling (both p < 0.001). Survival discharge was best explained by higher blood pH (p < 0.05), higher body temperature at admission (p < 0.01), and lower body temperature and heart rate after 24 hours of cooling (p < 0.01 and <0.001, respectively). Lower heart rate, higher body temperature at admission, and lower body temperature during cooling were associated with favorable short-term outcomes.

The fetus at the tipping point: modifying the outcome of fetal asphyxia

Brain injury around birth is associated with nearly half of all cases of cerebral palsy. Although brain injury is multifactorial, particularly after preterm birth, acute hypoxia-ischaemia is a major contributor to injury. It is now well established that the severity of injury after hypoxia-ischaemia is determined by a dynamic balance between injurious and protective processes. In addition, mothers who are at risk of premature delivery have high rates of diabetes and antepartum infection/inflammation and are almost universally given treatments such as antenatal glucocorticoids and magnesium sulphate to reduce the risk of death and complications after preterm birth. We review evidence that these common factors affect responses to fetal asphyxia, often in unexpected ways. For example, glucocorticoid exposure dramatically increases delayed cell loss after acute hypoxia-ischaemia, largely through secondary hyperglycaemia. This critical new information is important to understand the effects of clinical treatments of women whose fetuses are at risk of perinatal asphyxia.

Antenatal dexamethasone before asphyxia promotes cystic neural injury in preterm fetal sheep by inducing hyperglycemia

Antenatal glucocorticoid therapy significantly improves the short-term systemic outcomes of prematurely born infants, but there is limited information available on their impact on neurodevelopmental outcomes in at-risk preterm babies exposed to perinatal asphyxia. Preterm fetal sheep (0.7 of gestation) were exposed to a maternal injection of 12 mg dexamethasone or saline followed 4 h later by asphyxia induced by 25 min of complete umbilical cord occlusion. In a subsequent study, fetuses received titrated glucose infusions followed 4 h later by asphyxia to examine the hypothesis that hyperglycemia mediated the effects of dexamethasone. Post-mortems were performed 7 days after asphyxia for cerebral histology. Maternal dexamethasone before asphyxia was associated with severe, cystic brain injury compared to diffuse injury after saline injection, with increased numbers of seizures, worse recovery of brain activity, and increased arterial glucose levels before, during, and after asphyxia. Glucose infusions before asphyxia replicated these adverse outcomes, with a strong correlation between greater increases in glucose before asphyxia and greater neural injury. These findings strongly suggest that dexamethasone exposure and hyperglycemia can transform diffuse injury into cystic brain injury after asphyxia in preterm fetal sheep.

Cardiovascular Supportive Therapies for Neonates With Asphyxia - A Literature Review of Pre-clinical and Clinical Studies

Asphyxiated neonates often have hypotension, shock, and poor tissue perfusion. Various "inotropic" medications are used to provide cardiovascular support to improve the blood pressure and to treat shock. However, there is incomplete literature on the examination of hemodynamic effects of these medications in asphyxiated neonates, especially in the realm of clinical studies (mostly in late preterm or term populations). Although the extrapolation of findings from animal studies and other clinical populations such as children and adults require caution, it seems appropriate that findings from carefully conducted pre-clinical studies are important in answering some of the fundamental knowledge gaps. Based on a literature search, this review discusses the current available information, from both clinical studies and animal models of neonatal asphyxia, on common medications used to provide hemodynamic support including dopamine, dobutamine, epinephrine, milrinone, norepinephrine, vasopressin, levosimendan, and hydrocortisone.

Continuous glucose monitoring in neonates: a review

Continuous glucose monitoring (CGM) is well established in the management of diabetes mellitus, but its role in neonatal glycaemic control is less clear. CGM has provided important insights about neonatal glucose metabolism, and there is increasing interest in its clinical use, particularly in preterm neonates and in those in whom glucose control is difficult. Neonatal glucose instability, including hypoglycaemia and hyperglycaemia, has been associated with poorer neurodevelopment, and CGM offers the possibility of adjusting treatment in real time to account for individual metabolic requirements while reducing the number of blood tests required, potentially improving long-term outcomes. However, current devices are optimised for use at relatively high glucose concentrations, and several technical issues need to be resolved before real-time CGM can be recommended for routine neonatal care. These include: 1) limited point accuracy, especially at low or rapidly changing glucose concentrations; 2) calibration methods that are designed for higher glucose concentrations of children and adults, and not for neonates; 3) sensor drift, which is under-recognised; and 4) the need for dynamic and integrated metrics that can be related to long-term neurodevelopmental outcomes. CGM remains an important tool for retrospective investigation of neonatal glycaemia and the effect of different treatments on glucose metabolism. However, at present CGM should be limited to research studies, and should only be introduced into routine clinical care once benefit is demonstrated in randomised trials.