By LEE BOWMAN
Scripps Howard News Service
October 12, 2005
The study, published Thursday in The New England Journal of Medicine, is the largest experiment using the chilling technique on newborns.
The treatment relies on the same physical reactions to cold that have been seen over the years in hypothermia and drowning victims who have survived long periods without oxygen while immersed in cold water.
The 205 babies in the three-year study all suffered from a lack of oxygen due to birth complications, ranging from compression of the umbilical cord or placenta, tearing of the placenta from the uterine wall before birth or rupture of the uterus.
Between 60,000 and 80,000 of the 4 million babies born in the United States each year are at risk of death or disability because of such complications that can occur shortly before or during labor and delivery.
Cooling the body to about 92 degrees and inducing mild hypothermia reduces the brain's need for oxygen and slows other processes that might otherwise lead to permanent brain damage.
Half of the newborns were randomly assigned within the first six hours of life to have the temperature lowered using a special chilled-water blanket and kept at that lower temperature for three days before being gradually warmed back to 98.6 degrees.
Infants in both the hypothermia group and the control group received standard intensive care, including monitoring of vital signs, and were watched for signs of organ dysfunction.
Each of the babies was evaluated 18 to 22 months later at one of the 15 children's hospitals around the country that took part in the study, headed by Dr. Seetha Shankaran, a neonatal specialist at Wayne State University School of Medicine in Detroit.
Death or significant disability, such as cerebral palsy, occurred in 45 of the 102 babies in the hypothermia group, or 44 percent, compared with 64 of 103 babies, or 62 percent, who received normal care. No significant side effects were reported from the treatment, aside from some dryness and hardening of the skin where it came into contact with the chilled blankets.
"The experimental cooling of newborns to prevent death and injury from oxygen deprivation during birth is extremely promising," said Dr. Duane Alexander, director of the National Institute of Child Health and Human Development, which sponsored the study through its Neonatal Research Network.
"Yet it would be premature to implement the study results under any but the most carefully controlled and monitored circumstances," Alexander added. "The potential for serious harm exists if the conditions followed in this protocol are not carried out precisely as they were during the study."
Dr. Rose Higgins, program officer for the network and a co-author of the study, cautioned that "most newborn intensive care units don't have the resources or experienced personnel to duplicate the carefully controlled conditions of the study."
Although animal studies of the hypothermia treatment had showed promise, a small pilot study in newborns done earlier had not shown any benefit. Higgins said three other studies of hypothermia treatment are now under way and should help determine the most effective way to use cooling for oxygen-deprived infants.
She said the NICHD is working with the American Academy of Pediatrics to develop practice guidelines for treating the infants, adding that the studies done so far have only involved full-term infants, so it's not known if the care would benefit or harm preterm babies.
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