the prognostic value of amplitude integrated EEG (aEEG) 3 and 6 hours
term, asphyxiated infants were studied (from two different centres),
using the Cerebral Function Monitor (CFM Lectromed). The different aEEG
tracings were compared using pattern recognition (flat tracing mainly
isoelectric (FT); continuous extremely low voltage (CLV);
burst-suppression (BS); discontinuous normal voltage (DNV); continuous
normal voltage (CNV)) with subsequent outcome.
eight infants were followed up for more than 12 months (range 12 months
to 6 years).Twenty one out of 68 infants (31%) showed a change in
pattern from 3 to 6 hours, but this was only significant in five cases
(24%). In three this changed from BS to CNV with a normal outcome. One
infant showed a change in pattern from CNV to FT and had a major
handicap at follow up. Another infant showed a change in pattern from
DNV to BS, and developed a major handicap at follow up. The other 16 infants did not have any significant changes in pattern: 11 infants had
CLV, BS, or FT at 3 and 6 hours and died (n = 9) in the neonatal period
or developed a major handicap (n = 2). Five infants had a CNV or DNV
pattern at 3 and 6 hours, with a normal outcome. The sensitivity and
specificity of BS, together with FT and CLV, for poor outcome at 3 hours was 0.85 and 0.77, respectively; at 6 hours 0.91 and 0.86, respectively. The positive predictive value (PPV) was 78% and the
negative predictive value (NPV) 84% 3 hours after birth. At 6 hours
the PPV was 86% and the NPV was 91%.
could be very useful for selecting those infants who might benefit from
intervention after birth asphyxia.
The background pattern in single channel amplitude integrated EEG recordings (aEEG) was recorded in 47 infants within the first six hours after birth to see if this could predict outcome after birth asphyxia. The aEEG background pattern during the first six hours of life was continuous and of normal voltage in 26 infants. All these infants survived; 25 were healthy, one had delayed psychomotor development. A continuous but extremely low voltage pattern was present in two infants, both of whom survived with severe handicap. Five infants had flat (mainly isoelectric) tracings during the first six hours of life; four died in the neonatal period, and one survived with severe neurological handicap. Burst-suppression pattern was identified in 14 infants, of whom five died, six survived with severe handicap, and three were healthy at follow up. The type of background pattern recorded within the first six postnatal hours in the aEEG tracings predicted outcome correctly in 43 of 47 (91.5%) infants. Use of aEEG monitoring can predict outcome, with a high degree of accuracy, after birth asphyxia, within the first six hours after birth. The predictive value of a suppression-burst pattern was, however, somewhat lower than the other background patterns. The aEEG seems to be a feasible technique for identifying infants at high risk of subsequent brain damage who might benefit from interventionist treatment after asphyxia.
Objective: To assess the time course of recovery of severely abnormal initial amplitude integrated electroencephalographic (aEEG) patterns (flat trace (FT), continuous low voltage (CLV), or burst suppression (BS)) in full term asphyxiated neonates, in relation to other neurophysiological and neuroimaging findings and neurodevelopmental outcome.
Methods: A total of 190 aEEGs of full term infants were reviewed. The neonates were admitted within 6 hours of birth to the neonatal intensive care unit because of perinatal asphyxia, and aEEG recording was started immediately. In all, 160 infants were included; 65 of these had an initial FT or CLV pattern and 25 an initial BS pattern. Neurodevelopmental outcome was assessed using a full neurological examination and the Griffiths' mental developmental scale.
Results: In the FT/CLV group, the background pattern recovered to continuous normal voltage within 24 hours in six of the 65 infants (9%). All six infants survived the neonatal period; one had a severe disability, and five were normal at follow up. In the BS group, the background pattern improved to normal voltage in 12 of the 25 infants (48%) within 24 hours. Of these infants, one died, five survived with moderate to severe disability, two with mild disability, and four were normal. The patients who did not recover within 24 hours either died in the neonatal period or survived with a severe disability.
Conclusion: In this study there was a small group of infants who presented with a severely abnormal aEEG background pattern within six hours of birth, but who achieved recovery to a continuous normal background pattern within the first 24 hours. Sixty one percent of these infants survived without, or with a mild, disability.
The objectives of this prospective cohort study were to identify amplitude-integrated electroencephalography (aEEG) background patterns predictive of severe intracranial hemorrhage. Thirty ventilated preterm newborns <1000 grams were assessed using an aEEG cerebral function monitor and ultrasound measurement of cerebral blood flow (CBF) velocity at time of surfactant administration and tracheal suctioning simultaneously during first 48 hours of life. Birth weight was 624 ± 200 g (mean ± SD) and gestational age was 25 ± 2 weeks. Background electrical activity was predominantly discontinuous in 72% of infants. A sharp increase in electrical activity/burst density was observed during surfactant administration and tracheal suctioning in most infants with a 33.5 % increase in mean CBF velocity. Burst suppression with low voltage was identified in 57% infants with grade 3-4 Intracranial hemorrhage, while no infant without hemorrhage exhibited this pattern (P = .014). We conclude that aEEG low voltage burst suppression might have useful clinical applications with 100% positive vale for severe intracranial hemorrhage.
Therapeutic hypothermia (TH) is becoming standard of care in newborns with hypoxic-ischemic encephalopathy (HIE). The prognostic value of the EEG and the incidence of seizures during TH are uncertain.
To describe evolution of EEG background and incidence of seizures during TH, and to identify EEG patterns predictive for MRI brain injury.
A total of 41 newborns with HIE underwent TH. Continuous video-EEG was performed during hypothermia and rewarming. EEG background and seizures were reported in a standardized manner. Newborns underwent MRI after rewarming. Sensitivity and specificity of EEG background for moderate to severe MRI brain injury was assessed at 6-hour intervals during TH and rewarming.
EEG background improved in 49%, remained the same in 38%, and worsened in 13%. A normal EEG had a specificity of 100% upon initiation of monitoring and 93% at later time points. Burst suppression and extremely low voltage patterns held the greatest prognostic value only after 24 hours of monitoring, with a specificity of 81% at the beginning of cooling and 100% at later time points. A discontinuous pattern was not associated with adverse outcome in most patients (73%). Electrographic seizures occurred in 34% (14/41), and 10% (4/41) developed status epilepticus. Seizures had a clinical correlate in 57% (8/14) and were subclinical in 43% (6/14).
Continuous video-EEG monitoring in newborns with HIE undergoing TH provides prognostic information about early MRI outcome and accurately identifies electrographic seizures, nearly half of which are subclinical.
To characterize early amplitude-integrated electroencephalogram (aEEG) and single-channel EEG (aEEG/EEG) in very preterm (VPT) infants for prediction of long-term outcome.
Forty-nine infants with median (range) gestational age of 25 (22–30) weeks.
Amplitude-integrated electroencephalogram/EEG recorded during the first 72 h and analysed over 0–12, 12–24, 24–48 and 48–72 h, for background pattern, sleep–wake cycling, seizures, interburst intervals (IBI) and interburst percentage (IB%). In total, 2614 h of single-channel EEG examined for seizures. Survivors were assessed at 2 years corrected age with a neurological examination and Bayley Scales of Infant Development-II. Poor outcome was defined as death or survival with neurodevelopmental impairment. Good outcome was defined as survival without impairment.
Thirty infants had good outcome. Poor outcome (n = 19) was associated with depressed aEEG/EEG already during the first 12 h (p = 0.023), and with prolonged IBI and higher IB% at 24 h. Seizures were present in 43% of the infants and associated with intraventricular haemorrhages but not with outcome. Best predictors of poor outcome were burst-suppression pattern [76% correctly predicted; positive predictive value (PPV) 63%, negative predictive value (NPV) 91%], IBI > 6 sec (74% correctly predicted; PPV 67%, NPV 79%) and IB% > 55% at 24 h age (79% correctly predicted; PPV 72%, NPV 80%). In 35 infants with normal cerebral ultrasound during the first 3 days, outcome was correctly predicted in 82% by IB% (PPV 82%, NPV 83%).
Long-term outcome can be predicted by aEEG/EEG with 75–80% accuracy already at 24 postnatal hours in VPT infants, also in infants with no early indication of brain injury.
Burst suppression; Cranial ultrasound; Interburst interval; Neurodevelopmental impairment; Seizure
To evaluate their prognostic value, five different non-invasive techniques were used on 34 full term infants with hypoxic-ischaemic encephalopathy (HIE) within six hours of delivery. Cranial ultrasonography, the resistance index (RI) of the middle cerebral artery obtained with Doppler ultrasonography, somatosensory evoked potentials (SEPs), visual evoked potentials (VEPs) and the cerebral function monitor (CFM) were used. According to the criteria of Sarnat, 11 infants developed mild, seven moderate, and 16 severe encephalopathy. The CFM had the highest positive (PPV 84.2%) and negative predictive value (NPV 91.7%). All but one of the infants with a continuous pattern had a good outcome. The CFM of 11 cases with a suppression-burst pattern changed to a continuous pattern over 24 to 48 hours in four infants, and was associated with a normal outcome in three. All five cases with an isoelectric CFM died. The SEPs also provided useful information (PPV 81.8%; NPV 91.7%). VEPs were often delayed during the first hours or life and did not carry a poor prognosis in five of 14 cases (PPV 77.3%). Both ultrasonography and Doppler RI were of little value, as they were almost always normal at this early stage. In 34 full term infants with HIE, studied within 6 hours of life, the CFM and SEPs provided the most useful information about the expected course of encephalopathy and subsequent neurodevelopmental outcome.
Hypoxic ischaemic encephalopathy (HIE) in newborns can cause significant long-term neurological disability. The insult is a complex injury characterised by energy failure and disruption of cellular homeostasis, leading to mitochondrial damage. The importance of individual metabolic pathways, and their interaction in the disease process is not fully understood. The aim of this study was to describe and quantify the metabolomic profile of umbilical cord blood samples in a carefully defined population of full-term infants with HIE.
Methods and Findings
The injury severity was defined using both the modified Sarnat score and continuous multichannel electroencephalogram. Using these classification systems, our population was divided into those with confirmed HIE (n = 31), asphyxiated infants without encephalopathy (n = 40) and matched controls (n = 71). All had umbilical cord blood drawn and biobanked at −80°C within 3 hours of delivery. A combined direct injection and LC-MS/MS assay (AbsolutIDQ p180 kit, Biocrates Life Sciences AG, Innsbruck, Austria) was used for the metabolomic analyses of the samples. Targeted metabolomic analysis showed a significant alteration between study groups in 29 metabolites from 3 distinct classes (Amino Acids, Acylcarnitines, and Glycerophospholipids). 9 of these metabolites were only significantly altered between neonates with Hypoxic ischaemic encephalopathy and matched controls, while 14 were significantly altered in both study groups. Multivariate Discriminant Analysis models developed showed clear multifactorial metabolite associations with both asphyxia and HIE. A logistic regression model using 5 metabolites clearly delineates severity of asphyxia and classifies HIE infants with AUC = 0.92. These data describe wide-spread disruption to not only energy pathways, but also nitrogen and lipid metabolism in both asphyxia and HIE.
This study shows that a multi-platform targeted approach to metabolomic analyses using accurately phenotyped and meticulously biobanked samples provides insight into the pathogenesis of perinatal asphyxia. It highlights the potential for metabolomic technology to develop a diagnostic test for HIE.
To evaluate the diagnostic accuracy of 2 quantitative EEG display tools, color density spectral array (CDSA) and amplitude-integrated EEG (aEEG), for seizure identification in the intensive care unit (ICU).
A set of 27 continuous EEG recordings performed in pediatric ICU patients was transformed into 8-channel CDSA and aEEG displays. Three neurophysiologists underwent 2 hours of training to identify seizures using these techniques. They were then individually presented with a series of CDSA and aEEG displays, blinded to the raw EEG, and asked to mark any events suspected to be seizures. Their performance was compared to seizures identified on the underlying conventional EEG.
The 27 EEG recordings contained 553 discrete seizures over 487 hours. The median sensitivity for seizure identification across all recordings was 83.3% using CDSA and 81.5% using aEEG. However, among individual recordings, the sensitivity ranged from 0% to 100%. Factors reducing the sensitivity included low-amplitude, short, and focal seizures. False-positive rates were generally very low, with misidentified seizures occurring once every 17–20 hours.
Both CDSA and aEEG demonstrate acceptable sensitivity and false-positive rates for seizure identification among critically ill children. Accuracy of these tools would likely improve during clinical use, when findings can be correlated in real-time with the underlying raw EEG. In the hands of neurophysiologists, CDSA and aEEG displays represent useful screening tools for seizures during continuous EEG monitoring in the ICU. The suitability of these tools for bedside use by ICU nurses and physicians requires further study.
= amplitude-integrated EEG;
= color density spectral array;
= fast-Fourier transformation;
= intensive care unit.
AIM—To determine the predictive value of plasma
and cerebrospinal fluid (CSF) tumour necrosis factor-α (TNF-α) and
interleukin-1β (IL-1β) concentrations on the outcome of
hypoxic-ischaemic encephalopathy (HIE) in full term infants.
METHODS—Thirty term infants with HIE were included
in the study. HIE was classified according to the criteria of Sarnat
and Sarnat. Blood and CSF were obtained within the first 24 hours of
life and stored until assay. Five infants died soon after hypoxic
insult. Neurological examinations and Denver Developmental Screening
Test (DDST) were performed at 12 months in the survivors.
RESULTS—At the age of 12 months neurological
examination and DDST showed that 11 infants were normal; 14 had
abnormal neurological findings and/or an abnormal DDST result. Eleven
normal infants were classified as group 1 and 19 infants (14 with
abnormal neurological findings and/or an abnormal DDST and five who
died) as group 2.CSF IL-1β and TNF-α concentrations in group 2 were significantly higher than those in group 1. Plasma IL-1β and
TNF-α concentrations were not significantly different between the two
groups. IL-1β, but not TNF-α concentrations, in group 2 were even
higher than those in group 1, although non-survivors were excluded from
group 2. When the patients were evaluated according to the stages of Sarnat, the difference in the three groups was again significant. Patients whose CSF samples were taken within 6 hours of the hypoxic insult had higher IL-1β and TNF-α concentrations than the patients whose samples were taken after 6hours.
CONCLUSIONS—Both cytokines probably contribute to
the damage sustained by the central nervous system after hypoxic
insult. IL-1β seems to be a better predictor of HIE than TNF-α.
Amplitude-integrated EEG (aEEG) was introduced relatively recently into neonatal intensive care in the U.S.A. We aimed to evaluate whether aEEG has changed clinical care for neonates with seizures. All 202 neonates treated for seizures at our hospital from 2002 to 2007 were included in this study. Neonates monitored with aEEG (n=67) were compared to a contemporary control group of neonates who were not monitored, despite aEEG availability (n=57), and a historical control group of neonates treated for seizures before aEEG was introduced in our NICU (n=78). 82% of those treated with phenobarbital (137/167) continued treatment after discharge, with no difference among the groups. Adjusted for gestational age and length of stay, there was also no difference among groups in the number of neuroimaging studies or number of anticonvulsants per patient. Fewer patients in the aEEG group, compared to contemporary controls (n=16/67 vs. 29/57, p=0.001) or historical controls (n=38/78, p=0.002), were diagnosed clinically with seizures without electrographic confirmation. We conclude that introducing aEEG did not increase neuroimaging tests, nor did it alter anticonvulsant use. However, diagnostic precision for neonatal seizures improved after aEEG introduction, as fewer neonates were treated for seizures based solely on clinical findings, without electrographic confirmation.
neonatal seizures; electroencephalography; amplitude-integrated EEG; aEEG; EEG; hypoxic ischemic encephalopathy; phenobarbital
Neonatal seizures are common clinical conditions in both term and preterm neonates, yet there are no clinical management guidelines to direct care. We surveyed 193 international neurologists and neonatologists to assess management practices seizures in preterm and term neonates among neurologists, neonatologists, and specialists in neonatal neurology or neonatal neurocritical care. We found high reported rates of electroencephalogram (EEG) and amplitude-integrated EEG (aEEG) monitoring for detection of neonatal seizures, prevalent use of older anticonvulsant agents, and high rates of neuroimaging. Overall, responses were similar for term and preterm neonates, however term neonates were more likely to be more heavily investigated, with higher use of EEG and aEEG monitoring of at-risk neonates and higher use of MRI. Continuous monitoring and brain imaging in the setting of neonatal seizures are now standard of care in many centers, though management practices vary widely. Early recognition and management of neonatal seizures and possible underlying injury may lead to increased opportunities for stopping seizures, protecting the brain, and improving developmental outcomes in at risk neonates. There is urgent need for collaboration among neonatologists and neurologists to address the gaps in knowledge regarding management of neonatal seizures in term and preterm neonates.
Infant; neonate; Seizures; Electroencephalography; Magnetic resonance imaging
Hypoxic ischemic encephalopathy is a serious condition affecting infants which can result in death and disability. This is a summary of pathogenesis of HIE, animal studies of cooling for hypoxic and ischemic models, human hypothermia trials, and the American Academy of Pediatrics publication on hypothermia for HIE. Hypothermia for neonatal HIE is continuing to evolve as a therapy. Studies, gaps in knowledge and opportunities for research are presented herein.
Death or severe disability is so common following an Apgar score of 0 at 10 minutes in observational studies that the Neonatal Resuscitation Program suggests considering discontinuation of resuscitation after 10 minutes of effective CPR.
To determine if Apgar scores at 10 minutes are associated with death or disability in early childhood following perinatal hypoxic-ischemic encephalopathy (HIE).
Design, Setting, and Patients
This is a secondary analysis of infants enrolled in the NICHD Neonatal Research Network hypothermia trial. Infants ≥ 36 weeks gestation had clinical and/or biochemical abnormalities at birth, and encephalopathy at < 6 hours. Logistic regression and classification and regression tree (CART) analysis was used to determine associations between Apgar scores at 10 minutes and neurodevelopmental outcome adjusting for covariates. Associations are expressed as odds ratios (OR) and 95% confidence interval (CI).
Main Outcome Measure
Death or disability (moderate or severe) at 18–22 months of age.
Twenty of 208 infants were excluded (missing data). More than 90% of infants had Apgar scores of 0–2 at 1 minute and Apgars at 5 and 10 minutes shifted to progressively higher values; at 10 minutes 27% of infants had Apgar scores of 0–2. After adjustment each point decrease in Apgar score at 10 minutes was associated with a 45% increase in the odds of death or disability (OR 1.45, CI 1.22–1.72). Death or disability occurred in 76, 82 and 80% of infants with Apgar scores at 10 minutes of 0, 1 and 2, respectively. CART analysis indicated that Apgar scores at 10 minutes were discriminators of outcome.
Apgar scores at 10 minutes provide useful prognostic data before other evaluations are available for infants with HIE. Death or moderate/severe disability is common but not uniform with Apgar scores < 3; caution is needed before adopting a specific time interval to guide duration of resuscitation.
Apgar scores; Hypoxic-Ischemic Encephalopathy; cardiopulmonary resuscitation
Inflammatory cytokines may mediate hypoxic-ischemic (HI) injury and offer insights into the severity of injury and the timing of recovery. In our randomized, multicenter trial of hypothermia, we analyzed the temporal relationship of serum cytokine levels in neonates with hypoxic-ischemic encephalopathy (HIE) with neurodevelopmental outcome at 12 months. Serum cytokines were measured every 12 hours for 4 days in 28 hypothermic (H) and 22 normothermic (N) neonates with HIE. Monocyte chemotactic protein-1 (MCP-1) and interleukins (IL)-6, IL-8, and IL-10 were significantly higher in the H group. Elevated IL-6 and MCP-1 within 9 hours after birth and low macrophage inflammatory protein 1a (MIP-1a) at 60 to 70 hours of age were associated with death or severely abnormal neurodevelopment at 12 months of age. However, IL-6, IL-8, and MCP-1 showed a biphasic pattern in the H group, with early and delayed peaks. In H neonates with better outcomes, uniform down modulation of IL-6, IL-8, and IL-10 from their peak levels at 24 hours to their nadir at 36 hours was observed. Modulation of serum cytokines after HI injury may be another mechanism of improved outcomes in neonates treated with induced hypothermia.
chemokines; cytokines; hypoxic-ischemic brain injury; induced hypothermia
Hypoxic ischemic encephalopathy (HIE) remains a significant cause of mortality and long-term disability in late preterm and term infants. Mild therapeutic hypothermia to a rectal temperature of 34±0.5°C initiated as soon as possible within the first 6 h of life decreases mortality and severe long-term neurodevelopmental disabilities in infants with moderate HIE who are ≥36 weeks’ gestational age. There are minimal side effects, and the incidence of disability in survivors is not increased. Infants with severe encephalopathy are less likely to benefit from treatment. Cooling may be achieved by either total body or selective head cooling. As cooling is now considered a standard of care, infants ≥36 weeks’ gestational age who are depressed at birth should be assessed to determine whether they meet the criteria for cooling. There is currently no evidence that therapeutic hypothermia offers any benefit to infants <36 weeks’ gestational age.
Asphyxia; Cooling; Hypothermia; Hypoxic ischemic encephalopathy; Outcome
Therapeutic hypothermia instituted within 6 h of birth has been shown to improve neurodevelopmental outcomes in term newborns with moderate–to–severe hypoxic–ischemic encephalopathy (HIE). The majority of infants who would benefit from cooling are born at centers that do not offer the therapy, and adding the time for transport will result in delays in therapy, that may lead to suboptimal or no neuroprotection for some patients. Our objective was to evaluate the effect of our center's experience with therapeutic hypothermia on neonatal transport.
Retrospective review of all cases of therapeutic hypothermia at a single neonatal intensive care unit from 2005 to 2009.
Of 50 infants with HIE treated with hypothermia, 40 were outborn and 35 were cooled on transport. The majority of patients were passively cooled by the referring clinicians, then actively cooled by our transport team. Overcooling to <32 °C occurred in 34% of patients, but there were no significant differences in admission vital signs or laboratory values between overcooled and appropriately cooled infants. The average time after birth of initiation of passive cooling was 1.4 h and active cooling was 2.7 h compared with the time of admission to our unit of 5.9 h.
We discuss the important aspects of our program, including the education of referring and receiving clinicians and avoidance of overcooling.
hypothermia; hypoxic-ischemic encephalopathy; neontal transport; neuroprotection; birth asphyxia
We assessed the effects of hypoxic-ischemic encephalopathy (HIE) and whole-body hypothermia therapy on auditory brain stem evoked responses (ABRs) and distortion product otoacoustic emissions (DPOAEs). We performed serial assessments of ABRs and DPOAEs in newborns with moderate or severe HIE, randomized to hypothermia (n = 4) or usual care (n = 5). Participants were five boys and four girls with mean gestational age (standard deviation) of 38.9 (1.8) weeks. During the first week of life, peripheral auditory function, as measured by the DPOAEs, was disrupted in all nine subjects. ABRs were delayed but central transmission was intact, suggesting a peripheral rather than a central neural insult. By 3 weeks of age, peripheral auditory function normalized. Hypothermia temporarily prolonged the ABR, more so for waves generated higher in the brain stem but the effects reversed quickly on rewarming. Neonatal audiometric testing is feasible, noninvasive, and capable of enhancing our understanding of the effects of HIE and hypothermia on auditory function.
Hypoxia-ischemia; hypothermia; auditory evoked potentials; otoacoustic emissions
To evaluate the association between early hypocarbia and 18-22 month outcome among neonates with hypoxic-ischemic encephalopathy (HIE).
Data from the NICHD NRN randomized controlled trial of whole body hypothermia for neonatal HIE were used for this secondary observational study. Infants (n=204) had multiple blood gases recorded from birth-12h of study intervention (hypothermia vs. intensive care alone). The relationship between hypocarbia and outcome (death/disability at 18-22 months) was evaluated by unadjusted and adjusted analyses examining minimum PCO2 and cumulative exposure to PCO2 <35 mmHg. The relationship between cumulative PCO2 <35 mmHg (calculated as the difference between 35mmHg and the sampled PCO2 multiplied by the duration of time spent <35 mmHg) and outcome was evaluated by level of exposure (none-high) using a multiple logistic regression analysis with adjustments for pH, level of encephalopathy, treatment group (± hypothermia), time to spontaneous respiration and ventilator days; results were expressed as OR and 95% confidence intervals. Alternative models of CO2 concentration were explored to account for fluctuations in CO2.
Both minimum PCO2 and cumulative PCO2 <35mmHg were associated with poor outcome (P<0.05). Moreover, death/disability increased with greater cumulative exposure to PCO2 <35mmHg.
Hypocarbia is associated with poor outcome following HIE.
hypocarbia; hypoxic ischemic encephalopathy; whole body hypothermia; outcome; neurodevelopmental impairment
Background: Multiorgan dysfunction (MOD) is one of four consensus based criteria for the diagnosis of intrapartum asphyxia. The theoretical concept behind MOD is the diving reflex (conservation of blood flow to vital organs at the cost of non-vital organs).
Objectives: To assess the patterns of involvement of each major organ/system and combinations of involvement in infants with post-asphyxial hypoxic-ischaemic encephalopathy (HIE), and to describe this in relation to long term outcome.
Design: Retrospective cohort study.
Setting: Regional tertiary neonatal intensive care unit at the Hospital for Sick Children, Toronto, Canada.
Patients: Term neonates with post-intrapartal asphyxial HIE assessed for kidney, cardiovascular system, lung, and liver function.
Outcome: Death and presence or absence of severe neurodevelopmental disability.
Results: Out of 130 of 144 eligible infants with outcome data, 80 (62%) had severe adverse outcome and 50 (38%) had good outcome. All infants had evidence of MOD (at least one organ dysfunction in addition to HIE). Renal, cardiovascular, pulmonary, and hepatic dysfunction was present in 58–88% of infants with good outcome and 64–86% of infants with adverse outcome.
Conclusions: MOD was present in all the infants with severe post-asphyxial HIE. However, there was no association between MOD and outcome in these infants. No relation between individual or combinations of organ involvements and long term outcomes was observed.
Central gray matter damage, the hallmark of term acute perinatal hypoxia-ischemia, frequently leads to severe cerebral palsy and sometimes death. The precision with which these outcomes can be determined from neonatal imaging has not been fully explored. We evaluated the accuracy of early brain MRI for predicting death, the presence and severity of motor impairment, and ability to walk at 2 years in term infants with hypoxic-ischemic encephalopathy (HIE) and basal ganglia–thalamic (BGT) lesions.
From 1993 to 2007, 175 term infants with evidence of perinatal asphyxia, HIE, and BGT injury seen on early MRI scans were studied. BGT, white matter, posterior limb of the internal capsule (PLIC), and cortex and brainstem abnormality were classified by severity. Motor impairment was staged using the Gross Motor Function Classification System.
The severity of BGT lesions was strongly associated with the severity of motor impairment (Spearman rank correlation 0.77; p < 0.001). The association between white matter, cortical, and brainstem injury and motor impairment was less strong and only BGT injury correlated significantly in a logistic regression model. The predictive accuracy of severe BGT lesions for severe motor impairment was 0.89 (95% confidence interval 0.83–0.96). Abnormal PLIC signal intensity predicted the inability to walk independently by 2 years (sensitivity 0.92, specificity 0.77, positive predictive value 0.88, negative predictive value 0.85). Brainstem injury was the only factor with an independent association with death.
We have shown that in term newborns with HIE and BGT injury, early MRI can be used to predict death and specific motor outcomes.
Little is known about the effects of hypothermia therapy and subsequent rewarming on the PQRST intervals and heart rate variability (HRV) in term newborns with hypoxic-ischemic encephalopathy (HIE).
This study describes the changes in the PQRST intervals and HRV during rewarming to normal core body temperature of 2 newborns with HIE after hypothermia therapy.
Within 6 h after birth, 2 newborns with HIE were cooled to a core body temperature of 33.5°C for 72 h using a cooling blanket, followed by gradual rewarming (0.5°C per hour) until the body temperature reached 36.5°C. Custom instrumentation recorded the electrocardiogram from the leads used for clinical monitoring of vital signs. Generalized linear mixed models were calculated to estimate temperature-related changes in PQRST intervals and HRV.
For every 1°C increase in body temperature, the heart rate increased by 9.2 bpm (95% CI 6.8–11.6), the QTc interval decreased by 21.6 ms (95% CI 17.3–25.9), and low and high frequency HRV decreased by 0.480 dB (95% CI 0.052–0.907) and 0.938 dB (95% CI 0.460–1.416), respectively.
Hypothermia-induced changes in the electrocardiogram should be monitored carefully in future studies.
Hypoxic-ischemic encephalopathy; Hypothermia therapy; Electrocardiogram; QT interval; Heart rate variability
Moderate hypothermia in neonates with hypoxic–ischaemic encephalopathy might improve survival and neurological outcomes at up to 18 months of age, although complete neurological assessment at this age is difficult. To ascertain more precisely the effect of therapeutic hypothermia on neonatal cerebral injury, we assessed cerebral lesions on MRI scans of infants who participated in the Total Body Hypothermia for Neonatal Encephalopathy (TOBY) trial.
In the TOBY trial hypoxic–ischaemic encephalopathy was graded clinically according to the changes seen on amplitude integrated EEG, and infants were randomly assigned to intensive care with or without cooling by central telephone randomisation. The relation between allocation to hypothermia or normothermia and cerebral lesions was assessed by logistic regression with perinatal factors as covariates, and adjusted odds ratios (ORs) were calculated. The TOBY trial is registered, number ISRCTN 89547571.
325 infants were recruited in the TOBY trial between 2002 and 2006. Images were available for analysis from 131 infants. Therapeutic hypothermia was associated with a reduction in lesions in the basal ganglia or thalamus (OR 0·36, 95% CI 0·15–0·84; p=0·02), white matter (0·30, 0·12–0·77; p=0·01), and abnormal posterior limb of the internal capsule (0·38, 0·17–0·85; p=0·02). Compared with non-cooled infants, cooled infants had fewer scans that were predictive of later neuromotor abnormalities (0·41, 0·18–0·91; p=0·03) and were more likely to have normal scans (2·81, 1·13–6·93; p=0·03). The accuracy of prediction by MRI of death or disability to 18 months of age was 0·84 (0·74–0·94) in the cooled group and 0·81 (0·71–0·91) in the non-cooled group.
Therapeutic hypothermia decreases brain tissue injury in infants with hypoxic–ischaemic encephalopathy. The predictive value of MRI for subsequent neurological impairment is not affected by therapeutic hypothermia.
UK Medical Research Council; UK Department of Health.
The prognostic value of early neonatal continuous electroencephalographic recordings in hypoxic ischaemic encephalopathy was evaluated. Thirty seven full term infants with hypoxic ischaemic encephalopathy were studied. The electroencephalogram (EEG) was recorded using four or eight channel Oxford Medilog recorders and was started as soon as possible after birth. The recordings were initially visually analysed and divided into four categories: three in relation to the grade of discontinuity of the background activity (continuous, discontinuous, and maximum depression) and an additional fourth category to include status epilepticus.
The EEGs with discontinuous activity were then analysed by computer to obtain a more objective assessment of discontinuity. The results were related to neurological outcome. Continuous background activity was associated with a normal outcome in all but the three infants who had continuous, but asymmetrical EEGs and who developed contralateral hemiplegia. In the eight infants with discontinuous activity, the outcome appeared to be related to the grade of continuity and the presence of clear convulsions on the EEG. The 10 infants with maximum depression and status epilepticus had severe impairment.
These preliminary results suggest that continuous recording of EEGs could be used routinely in term infants with hypoxic ischaemic encephalopathy. Computer analysis can improve the value of this technique, allowing the identification of infants who might benefit from early therapeutic intervention.
While the number of survivors of term hypoxic-ischemic encephalopathy (HIE) is lower than the number of survivors of extreme prematurity, the proportion of neonates with long-term sequelae is higher. All neonates with Sarnat stages 2 (moderate) and 3 (severe) should be enrolled in follow-up programs. The present paper discusses the clinical and imaging diagnostic criteria for HIE, which are essential to decisions about follow-up. Prognostic indicators are also summarized. The recommendations for follow-up and intervention are based on the clinical condition of the baby at the time of discharge from intensive care, including an assessment of feeding, vision, hearing and whether seizures continue to be present. Early assessments (at four to eight months) focus on head growth, general health and motor neurodevelopment. Assessments at 12 to 24 months focus on cognitive skills and language development. Preschool assessments are also strongly recommended to provide for the identification of children requiring early education programs. Knowledge of long-term outcome and its secular changes enhance prognostication, and the evaluation of new preventive and therapeutic approaches.
Asphyxia; Follow-up; Outcome; Term infant