Cold Treatment Protects Against Infant Disability and Death From Oxygen Loss
Infant Cold Treatment
Lowering infants' body temperature to about 92 degrees Fahrenheit within the first 6 hours of life reduces the chances of disability and death among full term infants who failed to receive enough oxygen or blood to the brain during birth. This finding was reported by researchers in the Neonatal Research Network of the National Institute of Child Health and Human Development, one of the National Institutes of Health.
The study appears in the October 13, 2005 New England Journal of Medicine.
"The experimental cooling of newborns to prevent death and injury from oxygen deprivation during birth is extremely promising," said NICHD Director Duane Alexander, M.D. "Yet it would be premature to implement the study results under any but the most carefully controlled and monitored circumstances. The potential for serious harm exists if the conditions followed in this protocol are not carried out precisely as they were during the study, by personnel skilled in their use."
The study was led by Seetha Shankaran, M.D., of the Division of Neonatal-Perinatal Medicine, at Wayne State University School of Medicine in Detroit, one of the participating NICHD Neonatal Research Network study sites.
Hypoxic ischemic encephalopathy (HIE) occurs when an infant's brain fails to receive sufficient oxygen or sufficient blood before birth. HIE may occur hours before birth, or, in some cases, during labor and delivery. The condition may result from a variety of causes. These include compression of the placenta, tearing of the placenta from the uterine wall before birth, compression of the umbilical cord, and rupture of the uterus. Dr. Shankaran explained that HIE is estimated to occur from 0.5 to 1 times per every thousand births.
The study authors wrote that 10 percent of infants with moderate HIE die, as do 60 percent of infants with severe HIE. "Many, if not all," survivors of severe HIE experience major disability, they added.
Previous studies, conducted in laboratory animals, suggested that cooling the brain from 2 to 5 degrees Celsius after HIE could reduce the chances for the death and disability that often result from HIE, the authors wrote.
To conduct the study, researchers enrolled infants from the 15 centers making up the NICHD neonatal network. All the infants had experienced oxygen deprivation during the birth process. A total of 208 infants took part in the study. They were assigned at random to 1 of 2 groups, with 102 infants undergoing the experimental cooling (hypothermia) treatment and 106 receiving standard care. Standard care for HIE may involve placing the infant on a ventilator to assist breathing monitoring blood pressure, and providing fluids intravenously, and other newborn intensive care supportive therapies.
The infants were cooled by placing them on a soft plastic blanket through which water circulates. The blanket's temperature is regulated by computer. For the study, the blankets were set at 5 degrees Celsius (41 degrees Fahrenheit). The infant's temperatures were lowered to 33.5 degrees Celsius (92.3 degrees Fahrenheit), as measured by a temperature probe placed in an infant's esophagus. The infants in the hypothermia group were enrolled within the first 6 hours of birth, and remained on the cooled blanket for 72 hours. After 72 hours had passed, they were gradually warmed to a normal body temperature.
Infants in both the hypothermia group and the control group received standard newborn intensive care including monitoring of vital signs and were watched carefully for signs of organ dysfunction.
When the infants were examined at 18 to 22 months of age, 44 percent of those in the hypothermia group developed a moderate to severe disability or had died, as compared to 62 percent in the control group.
Dr. Shankaran explained that when the study's three principal outcomes