Cerebral Glucose Concentration in Neonatal Hypoxic-Ischemic Encephalopathy during Therapeutic Hypothermia

To determine cerebral glucose concentration and its relationship with glucose infusion rate (GIR) and blood glucose concentration in neonatal encephalopathy during therapeutic hypothermia (TH).

This was an observational study in which cerebral glucose during TH was quantified by magnetic resonance (MR) spectroscopy and compared with mean blood glucose at the time of scan. Clinical data (gestational age, birth weight, GIR, sedative use) that could affect glucose use were collected. The severity and pattern of brain injury on MR imaging were scored by a neuroradiologist. Student t test, Pearson correlation, repeated measures ANOVA, and multiple regression analysis were performed.

Three-hundred-sixty blood glucose values and 402 MR spectra from 54 infants (30 female infants; mean gestational age 38.6 ± 1.9 weeks) were analyzed. In total, 41 infants had normal-mild and 13 had moderate-severe injury. Median GIR and blood glucose during TH were 6.0 mg/kg/min (IQR 5-7) and 90 mg/dL (IQR 80-102), respectively. GIR did not correlate with blood or cerebral glucose. Cerebral glucose was significantly greater during than after TH (65.9 ± 22.9 vs 60.0 ± 25.2 mg/dL, P < .01), and there was a significant correlation between blood glucose and cerebral glucose during TH (basal ganglia: r = 0.42, thalamus: r = 0.42, cortical gray matter: r = 0.39, white matter: r = 0.39, all P < .01). There was no significant difference in cerebral glucose concentration in relation to injury severity or pattern.

During TH, cerebral glucose concentration is partly dependent on blood glucose concentration. Further studies to understand brain glucose use and optimal glucose concentrations during hypothermic neuroprotection are needed.