Lowering the body temperature of preterm infants (born at 33 to 35 weeks of pregnancy) with hypoxic ischemic encephalopathy (HIE) — a type of brain damage caused by oxygen loss — offers no benefits over standard care, according to a study funded by the National Institutes of Health (NIH). Previous studies of near-term and term infants (born after 36 weeks) with HIE found that this cooling treatment, which lowers body temperature to about 92 degrees Fahrenheit, significantly reduced the risk of death or disability by age 18 months (corrected for prematurity). However, the current findings show that such benefits are not observed for preterm infants with HIE. The authors noted that use of the cooling treatment in preterm infants has increased, despite little research on its effectiveness in this age group.
The study was conducted by Roger G. Faix, M.D., of the University of Utah, and colleagues at 19 newborn research centers. It appears in JAMA Pediatrics. Funding was provided by NIH’s Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD).
HIE-associated oxygen loss can result from compression of the umbilical cord, a tear in the uterus, or other complications at birth. Of 188 preterm infants with HIE born from 2015 to 2020, 88 infants were assigned at random to the cooling treatment and 80 were maintained at normal temperature. Researchers evaluated occurrences such as death and moderate to severe disability when the infants were 18 to 22 months old. They found that 35% of those receiving the cooling treatment and 29% kept at normal temperature had died or had a disability. More specifically, deaths occurred in 20% of those receiving cooling treatment and 12% of those receiving standard care. Overall, preterm infants who received the cooling therapy had a 74% higher risk of death or disability and an 87% higher risk of death.