Therapeutic hypothermia not effective for younger newborns, study finds

Key takeaways:

• Therapeutic hypothermia is frequently recommended for infants but mostly ineffective in premature newborns.
• “We still have much data to analyze,” researcher says.

WASHINGTON — The only evidence-based therapy for neonatal encephalopathy is not effective for younger newborns, researchers reported at the Pediatric Academic Societies Meeting.

Studies demonstrating the efficacy and safety of therapeutic hypothermia (TH) for hypoxic-ischemic encephalopathy (HIE) around birth in high income countries “have largely been limited to infants aged 36 weeks’ gestation or greater,” Roger G. Faix, MD, professor emeritus of pediatrics and neonatology at the University of Utah, told Healio.

“Many clinicians have opted to generalize the findings and have treated infants less than 36 weeks with TH, even though such infants may be at greater risk for life-threatening or quality-of-life-threatening issues that TH might make worse,” Faix said. “Our study was designed to assess safety and efficacy of TH for HIE in less mature infants, or 33 to 35 weeks’ gestation.”

The 5-year study, conducted in 16 NICUs between 2015 and 2020, enrolled 168 newborns born between 33 and 35 weeks, 6 days’ gestation who had neonatal encephalopathy. Half of the newborns received TH, and a normal temperature was kept for the other half for 72 hours. Researchers performed a brain MRI on infants at 7 to 21 days and neurodevelopmental testing with hearing and vision assessment at 18 to 22 months. In all, 27 infants died before follow-up.

The researchers found that TH was not effective at reducing death or moderate to severe disability among younger newborns. In fact, it was associated with a 77% probability of increased death compared with infants kept at a normal temperature.

“We were a bit surprised that there was no apparent benefit with TH and a suggestion — although within the bounds of statistical error — of some harm attributable to TH in this less mature population,” Faix said.

While noting it was “premature to speculate about next steps,” Faix said, “We still have much data to analyze that may identify particular subgroups of qualifying infants that have special risks for harm or benefit with TH.”

References:

Study: Common treatment for brain injury not effective for some newborns. https://medicalxpress.com/news/2023-04-common-treatment-brain-injury-effective.html. Published April 28, 2023. Accessed May 1, 2023.