Cerebral Glucose Metabolism and Early EEG/aEEG in Term Newborn Infants with Hypoxic-Ischemic Encephalopathy

Abstract

The objective was to investigate how early electrocortical background pattern, as recorded with amplitude integrated EEG (aEEG), correlates with global and regional cerebral glucose metabolism (CMRgl) measured by positron emission tomography during the subacute phase after birth asphyxia. Nineteen term infants with hypoxic-ischemic encephalopathy were investigated. The aEEG background was evaluated at 0 -6, 6 -12, 12-24, 24 -48, and 48 -72 h postnatal age, and classified into four categories according to increasing degree of abnormality. The aEEG were also evaluated for sleep-wake cycling and epileptic seizure activity. CMRgl was measured by positron emission tomography with 2-( 18 F) fluoro-2-deoxy-D-glucose at a median (range) postnatal age 10 (4 -24) d. Increasing degree of abnormality in aEEG correlated significantly with decreasing CMRgl: at 6 -12 h (Ϫ0.593; 0.012) (r value; p value), 12-24 h (Ϫ0.669; 0.003), and 24 -48 h (Ϫ0.569; 0.014) postnatal age. Presence of sleep-wake cycling at 0 -6 h (0.697; 0.012), 6 -12 h (0.668; 0.003), and 12-24 h (0.612; 0.009) of age correlated with increased CMRgl. Delayed seizure activity at 12-24 h correlated with decreased CMRgl (Ϫ0.661; 0.004). Infants with abnormal aEEG at 6 -12 h had lower CMRgl in all regions of the brain compared with infants with normal aEEG. CMRgl of any specific region of the brain was not significantly more correlated to aEEG than CMRgl of other regions. Early electrocortical background patterns, early presence of sleep-wake cycling, and delayed seizure activity were highly correlated with global CMRgl measured during the subacute phase after asphyxia, but did not correlate with any specific pattern of regional uptake. Abbreviations aEEG, amplitude integrated EEG BS, burst-suppression aEEG CMRgl, cerebral metabolic rate of glucose CP, cerebral palsy FDG, fluoro-deoxyglucose HIE, hypoxic-ischemic encephalopathy OM, orbito-meatal PET, positron emission tomography rCMRgl, regional cerebral metabolic rate of glucose ROI, region of interest SWC, sleep-wake cycling in aEEG SZA, epileptic seizure activity in aEEG Birth asphyxia in term newborn infants remains a considerable problem in perinatal medicine, with high risk of mortality and disability (1-3). To predict outcome, the clinical neurologic assessment in grading HIE has proved to be of great value during the first days of life (4 -6). We have recently shown that CMRgl is significantly lower in asphyxiated full-term infants who die or develop CP than in asphyxiated infants with no signs of impairment at follow up (7). To select infants for early cerebroprotective treatment, which is a likely option in the near future (8), specific methods are required for very early identification of the infants who are at the highest risk of becoming disabled. aEEG has been used for very early prediction of outcome in full-term infants after birth asphyxia. There is a high risk for neurologic injury when the background aEEG is abnormal during the first hours of life (9, 10).On postmortem examinations of newborn in...

Effects of Morphine and Midazolam on Sleep-Wake Cycling in Amplitude-Integrated Electroencephalography in Post-Surgical Neonates ≥32 Weeks of Gestational Age

“…The internal trigger for SWC is located in the brainstem and the presence of SWC in healthy term newborns is considered a sign of brain stem integrity [17,18] . In newborns with hypoxic-ischaemic encephalopathy, sleep organization can be altered and the presence of SWC on aEEG is considered to be a good prognostic sign [19] . Timing of onset of SWC has been shown to predict neurodevelopmental outcome [20] .…”

Tc-99m-HL91 imaging in the early detection of neuronal injury in a neonatal rat model of hypoxic ischemia*

“…Functional imaging, which assesses the biochemical alterations in neonatal hypoxic-ischemia, has been reported (10)(11)(12). These studies showed that hypoperfusion changes in specific areas correlated with the perirolandic lesions in children with neonatal asphyxia (10) and that cerebral glucose metabolism measured 8-12 days after asphyxia was highly correlated with the severity of hypoxic-ischemia (12).…”

“…Although conventional MRI is accurate and reproducible to show brain lesions in the first 3-4 days after birth, T1-and T2-weighted MRI may appear normal during the first 24 hrs after hypoxic-ischemia (1,8). Functional imaging, such as cerebral perfusion (10,11) and cerebral glucose metabolism (12), has been used to assess biochemical alterations in neonatal brain during the subacute and chronic stages after hypoxic-ischemia. An imaging agent that demonstrates increased uptake and retention in the damaged areas early after hypoxic-ischemia would be very valuable to identify the high-risk newborns for neuroprotective treatment.…”

Monitoring the Neonate: Basic Science

“…Abnormal aEEG is also associated with reduced oxygen consumption in the presence of high cerebral oxygen saturations (e.g., low fractional oxygen extraction) in afterbirth asphyxia [ 45 ]. Thorngren-Jerneck et al showed that abnormal aEEG patterns after neonatal H-I were associated with decreased glucose utilization as measured by positron emission tomography, while normal aEEG patterns were associated with normal glucose utilization [ 54 ]. Cooling is frequently instituted as a means of reducing the likelihood of long-term injury in infants who experience hypoxia-ischemia.…”