Impact of hypothermia on predictors of poor outcome: how do we decide to redirect care?

Abstract

Therapeutic hypothermia is now considered the standard of care for neonates with neonatal encephalopathy due to perinatal asphyxia. Outcomes following hypothermia treatment are favorable, as demonstrated in recent meta-analyses, but 45-50% of these neonates still suffer major disability or die due to global multi-organ injury or after redirection of care from life support due to severe brain injury. The ability to determine which patients are at highest risk of severe neurologic impairment and death and those in whom redirection of care should be considered is limited. This is especially true in the first few days after birth and in situations where the brain might be more significantly affected than other organ systems, making it difficult to discuss redirection of care. Clinical history, neurologic examination, serum biomarkers, neurophysiology [amplitude-integrated electroencephalography (aEEG) or EEG], near-infrared spectroscopy, and magnetic resonance imaging have all been studied as predictors of severe neurologic injury and poor outcome, although none is 100% predictive. Serial evaluation over time seems to be an important element to facilitate discussion regarding anticipated poor prognosis and decision-making for transition to comfort care. Thus far, brain monitoring in the form of aEEG and conventional EEG seem to be the best objective tools to identify the highest-risk patients. A delay or lack of recovery of the aEEG background during hypothermia treatment is an established important predictor of poor outcome (death or disability). This paper highlights the prognostic indicators that have been considered and focuses on aEEG as an important predictor of death or severe disability, which may facilitate conversations regarding redirection of care.

Keywords: Amplitude-integrated EEG; Magnetic resonance imaging; Neonatal encephalopathy; Redirection of care; Therapeutic hypothermia.