Hypothermia: A Neuroprotective Therapy for Neonatal Hypoxic-Ischemic Encephalopathy

In May, 2005, the National Institute of Child Health and Human Development (NICHD) convened a workshop to evaluate the status of knowledge regarding the safety and efficacy of hypothermia as a neuroprotective therapy for neonatal hypoxic-ischemic encephalopathy (HIE). 1 Participants, including the current and past chairs of the American Academy of Pediatrics Committee on Fetus and Newborn, reviewed current evidence and identified gaps in knowledge and clinical implications. They agreed that current evidence supports the conclusion that mild to moderate hypothermia holds promise for the amelioration of neural injury after a perinatal hypoxic-ischemic insult. The objectives of this commentary are to review briefly the background and current knowledge regarding the therapeutic efficacy and safety of sustained mild to moderate hypothermia to prevent death and severe disability in neonates who have experienced a significant hypoxic-ischemic insult and to urge caution and restraint in the immediate implementation of this therapy before more corroborating evidence has been published. The lack of a definitive therapeutic approach for HIE remains one of the unresolved clinical frustrations of contemporary neonatal medicine. The dismal prognosis for infants who sustain a severe asphyxial insult in the perinatal period has altered little despite advances in the application of diagnostic and multiorgan life-support techniques to newborns. 2–5 In part because the principal etiologies differ, therapeutic advances in the management of encephalopathy in older children and adults have not proved to be applicable to neonates. 6 In addition, unlike older patients, the etiology, onset, and duration of perinatal hypoxic-ischemic injury are varied and often unknown. ### Early Studies In the 1950s and 1960s, Miller and Westin7, 8 studied the physiologic basis for the neuroprotective role of hypothermia in the treatment of “asphyxia neonatorum, ” first in newborn animals and then in human newborns. They and others demonstrated improved survival without cerebral … Address correspondence to Lillian R. Blackmon, MD, University of Maryland School of Medicine, Room N5W68, 22 S Greene St, Baltimore, MD 21201. E-mail: lblackmonatpeds. umaryland. edu