Therapeutic hypothermia (TH) is now the gold standard treatment for infants with moderate to severe hypoxic ischemic encephalopathy, whereby the infant’s core body temperature is decreased within 6 hours after birth followed by slow rewarming for neuroprotection. This treatment slows the metabolic rate so cells can recover and prevent further damage. Neonatal encephalopathy can be due to different causes; care providers should take careful assessment of possible etiologies because this could lead to specific therapy that may improve prognosis. When a clear diagnosis of hypoxia-ischemia is known to be the reason for moderate to severe encephalopathy, TH is implemented if the infant meets the criteria. It has been shown to improve survival and outcome and reduce the risk of death or major neurodevelopmental disability at 18 months of age with data suggesting that the long term benefits resulted in improved neurocognitive outcomes persisting into middle childhood. The benefits of cooling outweigh the short-term risks related to hypothermia. Published hypothermia protocols have consistently used gestational age of at least ≥36 weeks at birth to qualify for TH and starting treatment within the first 6 hours after birth with systemic temperatures between 33°C and 35°C and continuing treatment for a total of 72 hours. Deviating from this protocol is not recommended as it may result in an increase in adverse outcomes; longer or deeper hypothermia showed an increase in mortality. Cooling infants who are <36 weeks’ gestation is not recommended because of insufficient evidence to evaluate risks and benefit in this patient population. The best benefit of TH is when it is started before 6 hours of life, but there may be a small benefit and low risk for infants with moderate HIE who have it started between 6 and 24 hours of life. A Cochrane review provided evidence from 11 randomized controlled trials (n = 1505 infants) that TH is beneficial in term and late preterm newborns with moderate to severe HIE.
There are 2 types of cooling, selective head cooling (SHC) and whole-body cooling (WBC), which is more common. Selective head cooling is done by using a cooling cap that circulates cold water that is placed on the infant’s head to lower the core temperature. Whole body cooling is done by using a cooling blanket or different types of wraps or mattresses that circulate cold water that is placed under the baby to lower the total body temperature. Both methods have been shown to be effective, and several recent studies showed no significant differences in adverse effects, neuromotor development at 12 months, or mortality rate between SHC and WBC when treating HIE. Further trials to determine the appropriate cooling technique are necessary to better understand the advantage of WBC versus SHC. Some neonatal intensive care units (NICUs) prefer using WBC because it is easier to administer and allows one to perform electroencephalogram monitoring on the infant. It is recommended that application of TH should only be done ...