Cerebral regional oxygen saturation trends in infants with hypoxic-ischemic encephalopathy

Neurological outcomes in neonatal hypoxic-ischemic encephalopathy (HIE) continue to be sub-optimal despite therapeutic hypothermia (TH). Cerebral near-infrared spectroscopy provides real-time regional oxygen saturation (CrSO₂) that may be a marker of adverse MRI findings and neurodevelopmental outcomes.

The aim of this study was to examine the value of CrSO₂ monitoring in infants with HIE undergoing TH.

In this prospective study, CrSO₂ was continuously recorded in 21 infants with HIE admitted for TH.

Brain MRI signal abnormalities at 2weeks were scored in individual brain region and classified as none/mild, moderate and severe. 13 infants completed Bayley Scales of Infant Development (BSID) testing at 18-24months.

Between 24 and 36h of life, there was a significant increase in odds of having moderate-severe brain MRI abnormalities with higher absolute CrSO₂ values. Per 10% increase in absolute CrSO₂, the odds ratio for moderate-severe brain MRI abnormalities was greatest at 30h (OR 3.78; confidence intervals (CI): 1.23-11.6, p=0.011). CrSO₂ increased more rapidly in infants with greater injury seen on MRI (0.20/h for MRI scores 0/1, by 0.48/h for MRI score 2, and by 0.68/h for MRI score 3, p=0.05). At 30h, absolute CrSO₂ correlated significantly with abnormal MRI findings in basal ganglia (92% vs. 78%, p=0.001), white matter (88% vs. 76%, p=0.01), posterior limb of internal capsule (92% vs. 78%, p=0.001), and brain stem (94% vs. 80%, p=0.03) but not with cortical injury (86% vs. 80%, p=0.17). Higher CrSO₂ beyond 24h correlated with greater odds of worse BSID scores.

Increasing CrSO₂ is associated with moderate-severe brain injury as assessed by MRI. Higher absolute CrSO2 values during TH correlates with subcortical injury on MRI and poor neurodevelopmental outcomes in infants with HIE undergoing TH. CrSO₂ can inform providers seeking early identification of patients at risk of worse injury who may benefit from further intervention.