Efficacy of refrigerated gel packs for therapeutic hypothermia in neonatal retrieval: a retrospective cohort study.

Objective: To determine the efficacy of refrigerated gel packs in achieving and maintaining target temperature in neonates receiving therapeutic hypothermia (TH) for hypoxic ischaemic encephalopathy during neonatal retrieval.

Design: Retrospective cohort study.

Setting: Paediatric Infant Perinatal Emergency Retrieval, Victoria, Australia.

Patients: 200 neonates treated with TH during retrieval between 1 January 2015 and 31 December 2020.

Interventions: Active cooling with refrigerated gel packs or passive cooling.

Main outcome measures: The primary outcomes were the proportion of neonates who achieved therapeutic cooling rectal temperature (33-34°C) within 6 hours of birth and maintained target temperature range once TH was achieved. Secondary outcomes included need for respiratory support, inotropes, anticonvulsant therapy, sedation and survival at 7 days of life.

Results: 200 neonates received TH. Median gestational age was 39 weeks and median birth weight 3300 g. 120 (60%) were actively cooled with refrigerated gel packs and the remainder passively cooled. 121 neonates (61%) reached target temperature within 6 hours and 14 (7%) after 6 hours of birth. Of those who achieved target temperature, 38% were maintained in therapeutic cooling range for the remainder of the retrieval.

Conclusions: Achieving and maintaining TH during neonatal retrieval with gel packs is challenging. Target temperature was not maintained in most neonates in this study. These findings support existing evidence favouring the use of servo-controlled cooling devices to optimise TH in the retrieval setting.