Cooling the body temperature of infants born with oxygen deficiencies improves their chances of surviving into early childhood compared with such children treated with usual care. The finding, by researchers affiliated with the Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) Neonatal Research Network, appears today in the New England Journal of Medicine.
Oxygen deprivation during the birth process, called hypoxic-ischemic encephalopathy (HIE), occurs because of complications during delivery. The condition is fairly rare, affecting about 1 of every 1000 births. In severe cases, death rates can reach 50%, and newborns who survive often sustain brain damage that can result in cerebral palsy, cognitive impairment, or hearing or vision loss. In an earlier study of 208 infants diagnosed with HIE within 6 hours of birth, the researchers found that inducing hypothermia and reducing an infant’s temperature to as low as 91.4°F for 72 hours improved survival at 18 to 22 months of age while maintaining an equivalent risk for disability, compared with those treated with usual care.
In the latest study, the researchers were able to follow up 190 of the original 208 infants to age 6 or 7 years and assess survival and cognitive deficits (as measured by IQ scores below 70). Of the 97 children in the hypothermia group, 27 died (28%) compared with 41 deaths among 93 children (44%) in the usual care group. About 30% of all children were found to have an IQ score below 70, but the 2 groups did not differ significantly in this regard.
“Our study provides strong evidence of long-term safety, given the lower death rate, and without an increase in disability in infants who underwent the cooling therapy and who have now reached school age,” said senior author Rosemary D. Higgins, MD, of the NICHD in a press briefing. “We are pleased that there is continued sustained benefit from cooling therapy.”