Comparison of Passive and Servo-Controlled Active Cooling for Infants with Hypoxic-Ischemic Encephalopathy during Neonatal Transfers.

The recent availability of servo-controlled cooling equipment on transport makes it possible to commence active cooling at the referral unit for infants with hypoxic-ischemic encephalopathy. This study aimed to compare the temperature and transfer variables in passively and actively cooled babies.  This is a retrospective cohort study comparing two groups-passively cooled (July 2011 to August 2012) versus actively cooled group (September 2012 to June 2013), following introduction of active hypothermia using servo-controlled cooling mattress by the London Neonatal Transfer Service (NTS).  Seventy-six infants were passively cooled and 69 were actively cooled. There was a significant difference between the temperatures of the two groups at each point in the transfer episode: on arrival of NTS, during stabilization, during transfer, and at the receiving hospital. Median time to achieve target temperature was 30 (95% confidence interval [CI]: 23-37) minutes in actively cooled, significantly shorter in comparison to 130 (95% CI: 83-177) minutes in passively cooled babies. Of the 69 newborns, 62 (90%) had temperature within target range at receiving center in actively cooled group as compared with 30/76 (40%) in passively cooled group.  The use of active cooling during neonatal transfer achieves target temperature in a shorter period and maintains better temperature stability.