Hypoglycaemia in cooled HIE infants ups risk of brain injury, poor neurocognitive development

Hypoglycaemia appears to be common among infants who receive therapeutic hypothermia (TH) for hypoxic-ischaemic encephalopathy (HIE), a new study reveals. Moreover, these infants also tend to show higher degrees of brain injury and lower cognitive function at school age.

Researchers conducted a single-centre, retrospective cohort analysis of 223 infants cooled for HIE. Hypoglycaemia, the study outcome, was defined as blood glucose <36.0 mg/dL at <2 hours after birth, and <46.8 mg/dL ≥2 hours after birth.

Infants also underwent brain magnetic resonance imaging (MRI) for the diagnosis of brain injuries. Motor and neurocognitive function were assessed at 2 and 5.5 years for all survivors using the Bayley Scales of Infant and Toddler Development–Third Edition and the Dutch version of the Wechsler Preschool and Primary Scale of Intelligence–Third edition (WPPSI-III-NL), respectively.

Seventy-nine cooled infants developed hypoglycaemia, yielding an incidence rate of 35.4 percent. Fifty cases were deemed to be severe, and 33 patients had hypoglycaemia within 6 hours of birth. Majority of episodes occurred within the first 24 hours after birth.

Multivariable analysis further showed that hypoglycaemia was a significant correlate of total MRI injury score (B, 3.6, 95 percent confidence interval [CI], 0.8–6.4; p=0.011) and lower WPPSI-III-NL total IQ scores at preschool age (B, –9.2, 95 percent CI, –17.1 to –1.3; p=0.023).

Moreover, hypoglycaemia significantly increased the odds of adverse outcomes among survivors at 5.5 years of age (adjusted odds ratio, 3.5, 95 percent CI, 1.3–9.2; p=0.011).

“Although it is not possible to conclude from this exploratory analysis whether the association between hypoglycaemia and brain injury is causal, our results suggest that hypoglycaemia might aggravate the effects of perinatal asphyxia,” the researchers said.

“Adequate anticipation and treatment to avoid large swings in glucose levels in asphyxiated infants receiving TH is crucial to minimize brain injury and neurodevelopmental sequelae,” they added. “Additional studies to investigate the association of hyperglycaemia with and without hypoglycaemia on brain injury and long-term outcome, and the optimal glucose levels in these newborns are warranted.”