Near-Infrared Spectroscopy and Continuous Glucose Monitoring During Therapeutic Hypothermia

Abstract

The relation between glucose homeostasis and cerebral blood flow (CBF) and their correlation to outcome in neonatal hypoxic-ischemic encephalopathy are unclear. In this short communication, we tried to determine whether changes in regional oxygen saturation (rSO2), as measured by near-infrared spectroscopy (NIRS), in asphyxiated neonates during therapeutic hypothermia correlate with the glycemic profile and whether NIRS and continuous glucose monitoring are useful in identifying cooled asphyxiated neonates at high risk of brain injury. Although there was no correlation between blood glucose and CBF in this small cohort of asphyxiated neonates (13 neonates admitted to the IRCCS Giannina Gaslini NICU in Genoa between March and September 2021), after 24 h of life, increased rSO₂ and glucose variability with a tendency toward hyperglycemia distinguished neonates who subsequently acquired brain injury from those who did not. As a result of this, it may be possible to monitor cerebral perfusion and metabolic changes as soon as possible after delivery in order to prevent poorer outcomes.

Keywords: continuous glucose monitoring; hypoxic-ischemic encephalopathy; near-infrared spectroscopy; therapeutic hypothermia.

FIG. 1.

Line charts comparing post-natal rSO₂ and CGM patterns of the two groups of neonates. There is no correlation between the two variables, but the increasing rSO₂ in neonates developing HI injury after 24 h of life, as well as the glucose variability and tendency to remain near high values, are clearly shown in comparison to the group of neonates not developing HI injury. rSO₂, regional oxygen saturation; CGM, continuous glucose monitoring; HI, hypoxic-ischemia.

FIG. 2.

Evolution of regional cerebral oxygenation saturation over the first days of life in asphyxiated neonates treated with hypothermia and 12 h after rewarming comparison based on the development of subsequent brain HI injury using box-and-whisker plots showing median, minimum, and maximum values for each group. Asphyxiated neonates who subsequently acquired brain injury after being treated with hypothermia are labeled as the “developing HI injury” group, whereas neonates who did not acquire such an injury are labeled as the “Not developing HI injury” group. rSO₂, regional oxygen saturation; HI, hypoxic-ischemia.