Early hypothermia shows long-term benefits in children starved of oxygen at birth

By Gene Emery

NEW YORK (Reuters Health) - The benefits of hypothermia treatment for newborns deprived of oxygen at birth persist at age six and seven, according to an updated evaluation of the TOBY trial published in the July 10 New England Journal of Medicine.

Babies whose perinatal asphyxial encephalopathy was treated with hypothermia were 31% more likely to have an IQ above 84 and 60% more likely to be free of neurologic problems.

"The fact that the benefits persisted to six or seven years of age is very reassuring. It means they're likely to persist throughout life," Dr. Denis Azzopardi of King's College London, the chief author, told Reuters Health by phone. "It's important to get long-term outcomes on these children."

"If there are any places where cooling is not yet the standard of care, this is the straw that should break that back," said Dr. Edward Shepherd, section chief for neonatology at Nationwide Children's Hospital in Ohio, who was not connected with the research.

"This is pretty convincing evidence that these babies should be cooled," he told Reuters Health in a telephone interview.

About 1700 full-term infants born in the U.S. each year face death, blindness, and other disabilities because their brains were temporarily cut off from blood or oxygen. Generally, as many as one in five die soon after delivery and one in four end up disabled.

Years ago, preliminary reports suggested that cooling might reduce the risk of damage. That research showed that the treatment lowered the risk of death or disability among toddlers age 18 to 24 months. The new study was designed to see if those benefits persisted.

Initially, 325 newborns with asphyxial encephalopathy, all of a gestational age over 35 weeks, were given standard care or 72 hours of hypothermia, where their rectal temperature was kept at 33 to 34 degrees using a cooling blanket. Treatment was initiated within six hours of birth.

The children were enrolled from 2002 to 2006. The vast majority were from the UK. The study was not blinded; parents and teachers knew if the child had received hypothermia therapy.

By age six or seven, 30% in the treatment group and 29% in the control group had died.

Yet the researchers found that 52% of the 145 children who were fully evaluated and who were treated with hypothermia had an IQ higher than 84, compared to 39% of the 132 in the control group (p=0.04).

In addition, while only 28% of the children in the control group survived without neurologic abnormalities, the rate was 45% in the treatment group (p=0.004). Hypothermia patients also scored better on a test of gross motor function and manual dexterity.

"We're talking about an additional 10 or 15 percent more babies who might come out of this unscathed," Dr. Shepherd said. "It tells us we're absolutely doing the right thing to cool these babies."

However, the mean IQ score was not significantly different - 103.6 with hypothermia therapy and 98.5 without (p=0.07). But the lack of significance may reflect the fact that the handicaps in many children meant that they could not be tested by that measure, Dr. Azzopardi said.

The same was true for verbal IQ, nonverbal performance, processing speed, memory and learning, sensorimotor processing, digit recall, reverse digit recall, and other measures. "But the trend always favors cooling," he said.

Only attention and executive function showed a significant difference (p=0.03).

SOURCE: http://bit.ly/1qwGhWg

N Engl J Med 2014.

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