Therapeutic Hypothermia for Neonatal Hypoxic Ischemic Encephalopathy

Efficacy of Therapeutic Hypothermia

Therapeutic hypothermia reduces the risk of death or major neurodevelopmental disability by approximately 22-33% in infants with moderate-to-severe HIE 1, 2
For every 5-7 infants treated with therapeutic hypothermia, one fewer infant will die or have significant neurodevelopmental disability 2
The absolute risk reduction for death or neurodevelopmental impairment at 18-24 months is approximately 151 fewer cases per 1000 infants treated 2

Cerebral palsy risk is reduced by approximately 48% with therapeutic hypothermia (RR 0.52; 95% CI 0.37-0.72) 2
Risk of blindness is reduced by approximately 52% (RR 0.48; 95% CI 0.22-1.03) 2
Risk of deafness is reduced by approximately 58% (RR 0.42; 95% CI 0.21-0.82) 2
The number needed to treat to prevent one case of cerebral palsy is approximately 12 infants 2

In moderate HIE, therapeutic hypothermia reduces the risk of death or major neurodevelopmental disability by approximately 33% (RR 0.67; 95% CI 0.56-0.81) 3
In severe HIE, the reduction is approximately 17% (RR 0.83; 95% CI 0.74-0.92) 3

Therapeutic hypothermia must be initiated within 6 hours of birth to be effective 1, 2, 3
Treatment should maintain strict temperature control at 33-34°C for 72 hours 2, 3
Rewarming should occur over at least 4 hours 2, 3
Cooling should only be conducted in neonatal care facilities with capabilities for multidisciplinary care 2, 3
Required resources include: intravenous therapy, respiratory support, pulse oximetry, antibiotics, anticonvulsants, and pathology testing 2, 3

Quality of evidence varies, with some studies showing risk of bias 2
There is a potential risk of persistent pulmonary hypertension with therapeutic hypothermia, though evidence is inconsistent 2
Implementation without proper protocols and monitoring may lead to harm, including risk of extreme hypothermia 2, 3

Further research is needed on optimal rewarming rates after hypothermia 4
Additional adequately powered randomized controlled trials are needed, particularly in resource-limited settings 2, 3