OBJECTIVES: Amplitude-integrated electroencephalogram (aEEG) at <6 hours is the best single outcome predictor in term infants with perinatal asphyxia at normothermia. Hypothermia has been used to treat those infants and proved to improve their outcome. The objectives of this study were to compare the predictive value of aEEG at <6 hours on outcomes in normothermia- and hypothermia-treated infants and to investigate the best outcome predictor (time to normal trace or sleep–wake cycling [SWC]) in normothermia- and hypothermia-treated infants. METHODS: Seventy-four infants were recruited by using the CoolCap entry criteria, and their outcomes were assessed by using the Bayley Scales of Infant Development II at 18 months. The aEEG was recorded for 72 hours. Patterns and voltages of aEEG backgrounds were assessed. RESULTS: The positive predictive value of an abnormal aEEG pattern at the age of 3 to 6 hours was 84% for normothermia and 59% for hypothermia. Moderate abnormal voltage background at 3 to 6 hours of age did not predict outcome. The recovery time to normal background pattern was the best predictor of poor outcome (96.2% in hypothermia, 90.9% in normothermia). Never developing SWC always predicted poor outcome. Time to SWC was a better outcome predictor for infants who were treated with hypothermia (88.5%) than with normothermia (63.6%). CONCLUSIONS: Early aEEG patterns can be used to predict outcome for infants treated with normothermia but not hypothermia. Infants with good outcome had normalized background pattern by 24 hours when treated with normothermia and by 48 hours when treated with hypothermia.

A hypoxic-ischaemic insult occurring around the time of birth may result in an encephalopathic state characterised by the need for resuscitation at birth, neurological depression, seizures and electroencephalographic abnormalities. There is an increasing risk of death or neurodevelopmental abnormalities with more severe encephalopathy. Current management consists of maintaining physiological parameters within the normal range and treating seizures with anticonvulsants. Studies in adult and newborn animals have shown that a reduction of body temperature of 3–4°C after cerebral insults is associated with improved histological and behavioural outcome. Pilot studies in infants with encephalopathy of head cooling combined with mild whole body hypothermia and of moderate whole body cooling to 33.5°C have been reported. No complications were noted but the group sizes were too small to evaluate benefit. TOBY is a multi-centre, prospective, randomised study of term infants after perinatal asphyxia comparing those allocated to "intensive care plus total body cooling for 72 hours" with those allocated to "intensive care without cooling". Full-term infants will be randomised within 6 hours of birth to either a control group with the rectal temperature kept at 37 +/- 0.2°C or to whole body cooling, with rectal temperature kept at 33–34°C for 72 hours. Term infants showing signs of moderate or severe encephalopathy +/- seizures have their eligibility confirmed by cerebral function monitoring. Outcomes will be assessed at 18 months of age using neurological and neurodevelopmental testing methods. At least 236 infants would be needed to demonstrate a 30% reduction in the relative risk of mortality or serious disability at 18 months. Recruitment was ahead of target by seven months and approvals were obtained allowing recruitment to continue to the end of the planned recruitment phase. 325 infants were recruited. Combined rate of mortality and severe neurodevelopmental impairment in survivors at 18 months of age. Neurodevelopmental impairment will be defined as any of: • Bayley mental developmental scale score less than 70 • Gross Motor Function Classification System Levels III – V • Bilateral cortical visual impairments Current Controlled Trials ISRCTN89547571

Therapeutic hypothermia (HT) is standard care for moderate and severe neonatal hypoxic-ischaemic encephalopathy (HIE), the leading cause of permanent brain injury in term newborns. However, the optimal temperature for HT is still unknown, and few preclinical studies have compared multiple HT treatment temperatures. Additionally, HT may not benefit infants with severe encephalopathy. In a neonatal rat model of unilateral hypoxia-ischaemia (HI), the effect of five different HT temperatures was investigated after either moderate or severe injury. At postnatal-day seven, rat pups underwent moderate or severe HI followed by 5 h at normothermia (37 °C), or one of five HT temperatures: 33.5 °C, 32 °C, 30 °C, 26 °C, and 18 °C. One week after treatment, neuropathological analysis of hemispheric and hippocampal area loss, and CA1 hippocampal pyramidal neuron count, was performed. After moderate injury, a significant reduction in hemispheric and hippocampal loss on the injured side, and preservation of CA1 pyramidal neurons, was seen in the 33.5 °C, 32 °C, and 30 °C groups. Cooling below 33.5 °C did not provide additional neuroprotection. Regardless of treatment temperature, HT was not neuroprotective in the severe HI model. Based on these findings, and previous experience translating preclinical studies into clinical application, we propose that milder cooling should be considered for future clinical trials.

Aim: Neuroprotection trials for neonatal encephalopathy use moderate or severe disability as an outcome, with the Bayley Scales of Infant Development, Second Edition (Bayley‐2) Index scores of <70 as part of the criteria. The Bayley Scales of Infant and Toddler, 3rd Development, Third Edition (Bayley‐3) have superseded Bayley‐2 and yield higher than expected scores in typically developing and high‐risk infants. The aim of this study, therefore, was to compare Bayley‐2 scores and Bayley‐3 scores in term‐born infants surviving neonatal encephalopathy treated with hypothermia.Method: Sixty‐one term‐born infants (37 males, 24 females; median gestational age at birth 40wks, range 36–42wks; median birthweight 3280g, range 2295–5050) following neonatal encephalopathy and hypothermia had contemporaneous assessment at 18 months using the Bayley‐2 and Bayley‐3.Results: The median Bayley‐3 Cognitive Composite score was 7 points higher than the median Bayley‐2 Mental Developmental Index (MDI) score and the median Bayley‐3 Motor Composite score was 18 points higher than the median Bayley‐2 Psychomotor Developmental Index (PDI) score. Ten children had a Bayley‐2 MDI of <70; only three children had Bayley‐3 combined Cognitive/Language scores of <70. Eleven children had Bayley‐2 PDI scores of <70 and four had modified Bayley‐3 Motor Composite scores of <70. Applying regression equations to Bayley‐3 scores adjusted rates of severe delay to similar proportions found using Bayley‐2 scores.Interpretation: Fewer children were classified with severe delay using the Bayley‐3 than the Bayley‐2, which prohibits direct comparison of scores. Increased Bayley‐3 cut‐off thresholds for classifying severe disability are recommended when comparing studies in this clinical group using Bayley‐2 scores.