Servo-controlled active cooling during transport of full-term infants with HIE improved their temperature stability and reduced their transfer time in comparison to passive cooling, researchers said October 21 in Pediatrics.
All babies cooled using the active approach were within the target temperature range when they arrived at the regional unit for treatment, versus 39% of the passively controlled infants, Dr. Topun Austin of Rosie Hospital in Cambridge, UK, and his colleagues found.
HIE occurs in two of every 1,000 newborns in developed countries, and in 10-20 per 1,000 babies in the developing world, Dr. Austin explained in an interview with Reuters Health. Therapeutic hypothermia, which involves cooling babies from their normal temperature of 37 degrees C to 33.5 degrees C, has been shown to help prevent brain damage in these infants.
“If you cool them by just a few degrees, a lot of these babies will have a normal neurological outcome at 18 months,” the investigator said. “It’s quite a dramatic improvement with quite an inexpensive treatment.”
One approach to cooling babies with HIE is to simply remove their clothes, Dr. Austin added, but this “passive cooling” approach can lead to overcooling. With active cooling, the baby is placed on a fluid-filled mattress. A rectal probe monitors the infant’s temperature, and the mattress is automatically heated or cooled to ensure that the target temperature is maintained.
Until now, no studies have compared outcomes with passive vs active cooling. To do so, Dr. Austin and his team reviewed data from a regional neonatal transfer team for 134 infants. The first 64 were treated with passive cooling; the other 70 infants were treated with active cooling after the purchase of a servo-controlled mattress.
Cooling started at an average of 46 minutes of age for the active group, vs 120 minutes for the control group. Median stabilization time was 153 minutes for the control group versus 133 minutes for the active group, while age at arrival was 504 minutes for the control group and 452 for the active group.
Dr. Austin and his colleagues are now investigating strategies for identifying infants with HIE as early as possible.
“It is important for the policy maker to make active cooling available during transport and maybe in the areas at medium and far distance from the referral centers,” said Dr. Mohamed Tagin, a neonatal fellow at the Hospital for Sick Children in Toronto, in email to Reuters Health. Dr. Tagin did not participate in the new study.
“I do agree that the active cooling process should be monitored at a tertiary care facility where appropriate monitoring and expertise are available for such complicated management,” Dr. Tagin added. “It is however very important to commence cooling as soon as the criteria for moderate to severe HIE have been fulfilled, given the available evidence about the improvement of the long-term outcome for those newborns.”
Dr. Tagin continued, “It is important when we discuss the issue of cooling to highlight that patient identification and early management is the most important step and often times it is done by a midwife or a family physician far away from further support. As the situation is stressful enough to those individuals, I believe there should be a system in place to give clear advice over the phone and maybe this already should be preceded with some training to different scenarios.”
But while active cooling should be the standard of care, he said, in the meantime “cooling should not be delayed, and passive cooling with frequent / continuous monitoring should be commenced once the patient has been identified.”