The Impact of Body Temperature on Neurologic Outcomes in Neonatal Aortic Arch Surgery Using Antegrade Cerebral Perfusion: A Scoping Review

Antegrade cerebral perfusion (ACP) and hypothermia are widely used neuroprotective strategies during neonatal aortic arch repairs. Still, over 50% of neonates exhibit new or worsened white matter injury in neuroimaging studies. Currently, clinical practices differ markedly, and we lack consensus about optimal ACP perfusion and temperature strategies. This review was designed to objectively identify the knowledge gap concerning the association between target body temperature and neurologic outcomes in neonatal aortic arch surgery and identify leads for future research. A literature search was done for articles on uni- and biventricular neonatal aortic arch surgery using ACP, with reporting on cooling temperatures and neurologic outcomes based on clinical evaluation or neuroimaging. Thirty-two studies were included, reporting temperatures ranging from 17°C to 32°C. Comparative studies did not demonstrate a neurologic difference between target body temperatures. The incidence of new neurologic injury based on neuroimaging was 58.1% (95% confidence interval: 45.8-70.3%) in the deep hypothermia group and 26.6% (95% confidence interval: 16.8-36.3%) in the moderate hypothermia group, but there was substantial heterogeneity in cardiac diagnoses between groups. The incidences of new neurological injury based on clinical examination and/or cerebral ultrasound were similar between mild (5.5%), moderate (4.0%), and deep hypothermia (5.0%). This literature search does not demonstrate a clear neurologic advantage or disadvantage of one target temperature over another. However, it does showcase practice diversity and current equipoise. Experimental studies are needed to gain an understanding of the effect of temperature changes on cerebral perfusion and autoregulation, and on neuroimaging and neurodevelopmental findings.