What are the long-term outcomes of hypothermia therapy for hypoxic-ischemic encephalopathy (HIE)?

Updated: Jul 18, 2018
  • Author: Santina A Zanelli, MD; Chief Editor: Dharmendra J Nimavat, MD, FAAP  more...
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School-age outcomes of infants in the NICHD trial were published in 2012. [93] At age of follow-up (6-7 years, 91% follow-up), the combined outcome of death or IQ score below 70 occurred in 62% of infants in the control group versus 47% of infants in the hypothermia group (P = 0.06). More infants in the control group died (44%) compared to 28% in the hypothermia group (P = 0.04). Reassuringly, this finding was not associated to increased risk of neurodevelopmental disability in survivors with a risk of death or severe disability in 60% of controls versus 41% in the hypothermia group (P = 0.03). [93]

In 2014, more follow-up results from the TOBY trial were published of children aged 6-7 years who had asphyxia encephalopathy as infants and were treated with hypothermia. [94] There were 75 of 145 survivors (52%) in the hypothermia group relative to 52 of 132 children (39%) in the control group. Children who received hypothermia shortly after birth were significantly more likely to have an IQ of 85 or higher at age 6-7 years, and they were less likely to moderate-to-severe disability compared to the control group. The study was insufficiently powered to determine whether hypothermia treatment led to positive neurocognitive effects at older ages, although the investigators were able to establish that early assessment at ages 18-21 months reliably predicted good functional outcomes at school age. [94]

Therapeutic hypothermia when applied within 6 hours of birth and maintained for 72 hours is the only therapy currently available that improves the outcomes of infants with moderate-to-severe HIE. [95, 96]

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