Greater Cooling of Oxygen-Deprived Infants Fails to Improve Survival

Study was halted early because of disappointing results

By Robert Preidt

Tuesday, December 23, 2014

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TUESDAY, Dec. 23, 2014 (HealthDay News) -- Longer and colder body cooling does not reduce the risk of death in newborns who have brain damage from a lack of oxygen, a new study finds.

The risk of death and disability in newborns with this condition -- called hypoxic ischemic encephalopathy -- can be reduced by lowering their body temperature to 33.5 degrees Celsius (92.3 Fahrenheit) for 72 hours, experts say.

Research has shown that longer and deeper cooling protects the brains of animals, so this study examined if the same would be true in humans.

The study included 364 full-term newborns with moderate to severe hypoxic ischemic encephalopathy who received one of the following cooling treatments: 33.5 degrees C for 72 hours, 32 degrees C (89.6 F) for 72 hours, 33.5 degrees C for 120 hours, and 32 degrees C for 120 hours.

The researchers planned to assess the infants' outcomes when they were 18 to 22 months old, but the study was halted early because of discouraging results.

Death rates while the infants were in the neonatal intensive care unit (NICU) were 7 percent for the 33.5 degrees/72 hours group. Death rates were at least twice that for the other groups, peaking at 17 percent for babies cooled to 32 degrees for 120 hours.

"Among neonates of at least 36 weeks' gestational age with moderate or severe hypoxic ischemic encephalopathy, deeper cooling or longer duration of cooling compared with hypothermia at 33.5 degrees C for 72 hours did not reduce NICU death. These results have implications for patient care and the design of future trials," Dr. Seetha Shankaran, of Wayne State University in Indiana, and colleagues wrote in the Dec. 24 issue of the Journal of the American Medical Association.

Further research is needed to find ways to improve survival for newborns with hypoxic ischemic encephalopathy, Nicola Robertson and Neil Marlow, of University College London in England, wrote in an accompanying editorial.

SOURCE: Journal of the American Medical Association, news release, Dec. 23, 2014

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