Benefits of starting hypothermia treatment within 6h vs. 6-12h in newborns with moderate neonatal hypoxic-ischemic encephalopathy

Abstract

Background: It has been suggested that mild hypothermia treatment of hypoxia-ischemic encephalopathy (HIE) should start within 6h after HIE, but many children are admitted to the hospital >6h, particularly in developing areas. We aimed to determine whether hypothermia treatment could remain effective within 12h after birth. Methods: According to their admission, 152 newborns were enrolled in the <6h and 6-12h after HIE groups. All newborns received conventional treatment combined with mild head hypothermia therapy, according to our routine clinical practice. Some newborns only received conventional treatment (lacking informed consent). All newborns received amplitude-integrated electroencephalography (aEEG) monitoring for 4h and neuron-specific enolase (NSE) measurement before and after 3days of therapy. Results: Compared to the conventional treatment, hypothermia significantly improved the aEEG scores and NSE values in all newborns of the <6-h group. In the 6-12-h group, the aEEG scores (F=5.67, P<0.05) and NSE values (F=4.98, P<0.05) were only improved in newborns with moderate HIE. Hypothermia treatment seems to have no effect in newborns with severe HIE after 6h (P>0.05). Hypothermia improved the rates of neonatal death and 18-month disability (all P<0.01). Conclusions: In newborns with moderate HIE, starting hypothermia therapy <6h and 6-12h after HIE showed curative effects. In those with severe HIE, only starting hypothermia therapy within 6h showed curative effects.